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Sample records for ocean climate model

  1. Climate Ocean Modeling on Parallel Computers

    NASA Technical Reports Server (NTRS)

    Wang, P.; Cheng, B. N.; Chao, Y.

    1998-01-01

    Ocean modeling plays an important role in both understanding the current climatic conditions and predicting future climate change. However, modeling the ocean circulation at various spatial and temporal scales is a very challenging computational task.

  2. Climate Modeling: Ocean Cavities below Ice Shelves

    SciTech Connect

    Petersen, Mark Roger

    The Accelerated Climate Model for Energy (ACME), a new initiative by the U.S. Department of Energy, includes unstructured-mesh ocean, land-ice, and sea-ice components using the Model for Prediction Across Scales (MPAS) framework. The ability to run coupled high-resolution global simulations efficiently on large, high-performance computers is a priority for ACME. Sub-ice shelf ocean cavities are a significant new capability in ACME, and will be used to better understand how changing ocean temperature and currents influence glacial melting and retreat. These simulations take advantage of the horizontal variable-resolution mesh and adaptive vertical coordinate in MPAS-Ocean, in order to place high resolutionmore » below ice shelves and near grounding lines.« less

  3. Mixing parametrizations for ocean climate modelling

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Moshonkin, Sergey; Diansky, Nikolay; Zalesny, Vladimir

    2016-04-01

    The algorithm is presented of splitting the total evolutionary equations for the turbulence kinetic energy (TKE) and turbulence dissipation frequency (TDF), which is used to parameterize the viscosity and diffusion coefficients in ocean circulation models. The turbulence model equations are split into the stages of transport-diffusion and generation-dissipation. For the generation-dissipation stage, the following schemes are implemented: the explicit-implicit numerical scheme, analytical solution and the asymptotic behavior of the analytical solutions. The experiments were performed with different mixing parameterizations for the modelling of Arctic and the Atlantic climate decadal variability with the eddy-permitting circulation model INMOM (Institute of Numerical Mathematics Ocean Model) using vertical grid refinement in the zone of fully developed turbulence. The proposed model with the split equations for turbulence characteristics is similar to the contemporary differential turbulence models, concerning the physical formulations. At the same time, its algorithm has high enough computational efficiency. Parameterizations with using the split turbulence model make it possible to obtain more adequate structure of temperature and salinity at decadal timescales, compared to the simpler Pacanowski-Philander (PP) turbulence parameterization. Parameterizations with using analytical solution or numerical scheme at the generation-dissipation step of the turbulence model leads to better representation of ocean climate than the faster parameterization using the asymptotic behavior of the analytical solution. At the same time, the computational efficiency left almost unchanged relative to the simple PP parameterization. Usage of PP parametrization in the circulation model leads to realistic simulation of density and circulation with violation of T,S-relationships. This error is majorly avoided with using the proposed parameterizations containing the split turbulence model

  4. Quantifying Key Climate Parameter Uncertainties Using an Earth System Model with a Dynamic 3D Ocean

    NASA Astrophysics Data System (ADS)

    Olson, R.; Sriver, R. L.; Goes, M. P.; Urban, N.; Matthews, D.; Haran, M.; Keller, K.

    2011-12-01

    Climate projections hinge critically on uncertain climate model parameters such as climate sensitivity, vertical ocean diffusivity and anthropogenic sulfate aerosol forcings. Climate sensitivity is defined as the equilibrium global mean temperature response to a doubling of atmospheric CO2 concentrations. Vertical ocean diffusivity parameterizes sub-grid scale ocean vertical mixing processes. These parameters are typically estimated using Intermediate Complexity Earth System Models (EMICs) that lack a full 3D representation of the oceans, thereby neglecting the effects of mixing on ocean dynamics and meridional overturning. We improve on these studies by employing an EMIC with a dynamic 3D ocean model to estimate these parameters. We carry out historical climate simulations with the University of Victoria Earth System Climate Model (UVic ESCM) varying parameters that affect climate sensitivity, vertical ocean mixing, and effects of anthropogenic sulfate aerosols. We use a Bayesian approach whereby the likelihood of each parameter combination depends on how well the model simulates surface air temperature and upper ocean heat content. We use a Gaussian process emulator to interpolate the model output to an arbitrary parameter setting. We use Markov Chain Monte Carlo method to estimate the posterior probability distribution function (pdf) of these parameters. We explore the sensitivity of the results to prior assumptions about the parameters. In addition, we estimate the relative skill of different observations to constrain the parameters. We quantify the uncertainty in parameter estimates stemming from climate variability, model and observational errors. We explore the sensitivity of key decision-relevant climate projections to these parameters. We find that climate sensitivity and vertical ocean diffusivity estimates are consistent with previously published results. The climate sensitivity pdf is strongly affected by the prior assumptions, and by the scaling

  5. Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the Goddard Institute for Space Studies (GISS) 8 deg x lO deg atmospheric General Circulation Model (GCM) to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

  6. Predicting Coupled Ocean-Atmosphere Modes with a Climate Modeling Hierarchy -- Final Report

    SciTech Connect

    Michael Ghil, UCLA; Andrew W. Robertson, IRI, Columbia Univ.; Sergey Kravtsov, U. of Wisconsin, Milwaukee

    The goal of the project was to determine midlatitude climate predictability associated with tropical-extratropical interactions on interannual-to-interdecadal time scales. Our strategy was to develop and test a hierarchy of climate models, bringing together large GCM-based climate models with simple fluid-dynamical coupled ocean-ice-atmosphere models, through the use of advanced probabilistic network (PN) models. PN models were used to develop a new diagnostic methodology for analyzing coupled ocean-atmosphere interactions in large climate simulations made with the NCAR Parallel Climate Model (PCM), and to make these tools user-friendly and available to other researchers. We focused on interactions between the tropics and extratropics throughmore » atmospheric teleconnections (the Hadley cell, Rossby waves and nonlinear circulation regimes) over both the North Atlantic and North Pacific, and the ocean’s thermohaline circulation (THC) in the Atlantic. We tested the hypothesis that variations in the strength of the THC alter sea surface temperatures in the tropical Atlantic, and that the latter influence the atmosphere in high latitudes through an atmospheric teleconnection, feeding back onto the THC. The PN model framework was used to mediate between the understanding gained with simplified primitive equations models and multi-century simulations made with the PCM. The project team is interdisciplinary and built on an existing synergy between atmospheric and ocean scientists at UCLA, computer scientists at UCI, and climate researchers at the IRI.« less

  7. Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the GISS 8 deg x lO deg atmospheric GCM to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

  8. Understanding and Improving Ocean Mixing Parameterizations for modeling Climate Change

    NASA Astrophysics Data System (ADS)

    Howard, A. M.; Fells, J.; Clarke, J.; Cheng, Y.; Canuto, V.; Dubovikov, M. S.

    2017-12-01

    Climate is vital. Earth is only habitable due to the atmosphere&oceans' distribution of energy. Our Greenhouse Gas emissions shift overall the balance between absorbed and emitted radiation causing Global Warming. How much of these emissions are stored in the ocean vs. entering the atmosphere to cause warming and how the extra heat is distributed depends on atmosphere&ocean dynamics, which we must understand to know risks of both progressive Climate Change and Climate Variability which affect us all in many ways including extreme weather, floods, droughts, sea-level rise and ecosystem disruption. Citizens must be informed to make decisions such as "business as usual" vs. mitigating emissions to avert catastrophe. Simulations of Climate Change provide needed knowledge but in turn need reliable parameterizations of key physical processes, including ocean mixing, which greatly impacts transport&storage of heat and dissolved CO2. The turbulence group at NASA-GISS seeks to use physical theory to improve parameterizations of ocean mixing, including smallscale convective, shear driven, double diffusive, internal wave and tidal driven vertical mixing, as well as mixing by submesoscale eddies, and lateral mixing along isopycnals by mesoscale eddies. Medgar Evers undergraduates aid NASA research while learning climate science and developing computer&math skills. We write our own programs in MATLAB and FORTRAN to visualize and process output of ocean simulations including producing statistics to help judge impacts of different parameterizations on fidelity in reproducing realistic temperatures&salinities, diffusivities and turbulent power. The results can help upgrade the parameterizations. Students are introduced to complex system modeling and gain deeper appreciation of climate science and programming skills, while furthering climate science. We are incorporating climate projects into the Medgar Evers college curriculum. The PI is both a member of the turbulence group at

  9. New Observationally-Based Metrics for the Analysis of Coupled Climate Model and Earth System Model Simulations of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Russell, J. L.

    2014-12-01

    The exchange of heat and carbon dioxide between the atmosphere and ocean are major controls on Earth's climate under conditions of anthropogenic forcing. The Southern Ocean south of 30°S, occupying just over ¼ of the surface ocean area, accounts for a disproportionate share of the vertical exchange of properties between the deep and surface waters of the ocean and between the surface ocean and the atmosphere; thus this region can be disproportionately influential on the climate system. Despite the crucial role of the Southern Ocean in the climate system, understanding of the particular mechanisms involved remains inadequate, and the model studies underlying many of these results are highly controversial. As part of the overall goal of working toward reducing uncertainties in climate projections, we present an analysis using new data/model metrics based on a unified framework of theory, quantitative datasets, and numerical modeling. These new metrics quantify the mechanisms, processes, and tendencies relevant to the role of the Southern Ocean in climate.

  10. Climate Ocean Modeling on a Beowulf Class System

    NASA Technical Reports Server (NTRS)

    Cheng, B. N.; Chao, Y.; Wang, P.; Bondarenko, M.

    2000-01-01

    With the growing power and shrinking cost of personal computers. the availability of fast ethernet interconnections, and public domain software packages, it is now possible to combine them to build desktop parallel computers (named Beowulf or PC clusters) at a fraction of what it would cost to buy systems of comparable power front supercomputer companies. This led as to build and assemble our own sys tem. specifically for climate ocean modeling. In this article, we present our experience with such a system, discuss its network performance, and provide some performance comparison data with both HP SPP2000 and Cray T3E for an ocean Model used in present-day oceanographic research.

  11. Ocean Heat and Carbon Uptake in Transient Climate Change: Identifying Model Uncertainty

    NASA Technical Reports Server (NTRS)

    Romanou, Anastasia; Marshall, John

    2015-01-01

    Global warming on decadal and centennial timescales is mediated and ameliorated by the oceansequestering heat and carbon into its interior. Transient climate change is a function of the efficiency by whichanthropogenic heat and carbon are transported away from the surface into the ocean interior (Hansen et al. 1985).Gregory and Mitchell (1997) and Raper et al. (2002) were the first to identify the importance of the ocean heat uptakeefficiency in transient climate change. Observational estimates (Schwartz 2012) and inferences from coupledatmosphere-ocean general circulation models (AOGCMs; Gregory and Forster 2008; Marotzke et al. 2015), suggest thatocean heat uptake efficiency on decadal timescales lies in the range 0.5-1.5 W/sq m/K and is thus comparable to theclimate feedback parameter (Murphy et al. 2009). Moreover, the ocean not only plays a key role in setting the timing ofwarming but also its regional patterns (Marshall et al. 2014), which is crucial to our understanding of regional climate,carbon and heat uptake, and sea-level change. This short communication is based on a presentation given by A.Romanou at a recent workshop, Oceans Carbon and Heat Uptake: Uncertainties and Metrics, co-hosted by US CLIVARand OCB. As briefly reviewed below, we have incomplete but growing knowledge of how ocean models used in climatechange projections sequester heat and carbon into the interior. To understand and thence reduce errors and biases inthe ocean component of coupled models, as well as elucidate the key mechanisms at work, in the final section we outlinea proposed model intercomparison project named FAFMIP. In FAFMIP, coupled integrations would be carried out withprescribed overrides of wind stress and freshwater and heat fluxes acting at the sea surface.

  12. Secular trends and climate drift in coupled ocean-atmosphere general circulation models

    NASA Astrophysics Data System (ADS)

    Covey, Curt; Gleckler, Peter J.; Phillips, Thomas J.; Bader, David C.

    2006-02-01

    Coupled ocean-atmosphere general circulation models (coupled GCMs) with interactive sea ice are the primary tool for investigating possible future global warming and numerous other issues in climate science. A long-standing problem with such models is that when different components of the physical climate system are linked together, the simulated climate can drift away from observation unless constrained by ad hoc adjustments to interface fluxes. However, 11 modern coupled GCMs, including three that do not employ flux adjustments, behave much better in this respect than the older generation of models. Surface temperature trends in control run simulations (with external climate forcing such as solar brightness and atmospheric carbon dioxide held constant) are small compared with observed trends, which include 20th century climate change due to both anthropogenic and natural factors. Sea ice changes in the models are dominated by interannual variations. Deep ocean temperature and salinity trends are small enough for model control runs to extend over 1000 simulated years or more, but trends in some regions, most notably the Arctic, differ substantially among the models and may be problematic. Methods used to initialize coupled GCMs can mitigate climate drift but cannot eliminate it. Lengthy "spin-ups" of models, made possible by increasing computer power, are one reason for the improvements this paper documents.

  13. Forcing, feedbacks and climate sensitivity in CMIP5 coupled atmosphere-ocean climate models

    DOE PAGES

    Andrews, Timothy; Gregory, Jonathan M.; Webb, Mark J.; ...

    2012-05-15

    We quantify forcing and feedbacks across available CMIP5 coupled atmosphere-ocean general circulation models (AOGCMs) by analysing simulations forced by an abrupt quadrupling of atmospheric carbon dioxide concentration. This is the first application of the linear forcing-feedback regression analysis of Gregory et al. (2004) to an ensemble of AOGCMs. The range of equilibrium climate sensitivity is 2.1–4.7 K. Differences in cloud feedbacks continue to be important contributors to this range. Some models show small deviations from a linear dependence of top-of-atmosphere radiative fluxes on global surface temperature change. We show that this phenomenon largely arises from shortwave cloud radiative effects overmore » the ocean and is consistent with independent estimates of forcing using fixed sea-surface temperature methods. Moreover, we suggest that future research should focus more on understanding transient climate change, including any time-scale dependence of the forcing and/or feedback, rather than on the equilibrium response to large instantaneous forcing.« less

  14. How ocean lateral mixing changes Southern Ocean variability in coupled climate models

    NASA Astrophysics Data System (ADS)

    Pradal, M. A. S.; Gnanadesikan, A.; Thomas, J. L.

    2016-02-01

    The lateral mixing of tracers represents a major uncertainty in the formulation of coupled climate models. The mixing of tracers along density surfaces in the interior and horizontally within the mixed layer is often parameterized using a mixing coefficient ARedi. The models used in the Coupled Model Intercomparison Project 5 exhibit more than an order of magnitude range in the values of this coefficient used within the Southern Ocean. The impacts of such uncertainty on Southern Ocean variability have remained unclear, even as recent work has shown that this variability differs between different models. In this poster, we change the lateral mixing coefficient within GFDL ESM2Mc, a coarse-resolution Earth System model that nonetheless has a reasonable circulation within the Southern Ocean. As the coefficient varies from 400 to 2400 m2/s the amplitude of the variability varies significantly. The low-mixing case shows strong decadal variability with an annual mean RMS temperature variability exceeding 1C in the Circumpolar Current. The highest-mixing case shows a very similar spatial pattern of variability, but with amplitudes only about 60% as large. The suppression of mixing is larger in the Atlantic Sector of the Southern Ocean relatively to the Pacific sector. We examine the salinity budgets of convective regions, paying particular attention to the extent to which high mixing prevents the buildup of low-saline waters that are capable of shutting off deep convection entirely.

  15. Projections of Ocean Acidification Under the U.N. Framework Convention of Climate Change Using a Reduced-Form Climate Carbon-Cycle Model

    NASA Astrophysics Data System (ADS)

    Hartin, C.

    2016-02-01

    Ocean chemistry is quickly changing in response to continued anthropogenic emissions of carbon to the atmosphere. Mean surface ocean pH has already decreased by 0.1 units relative to the preindustrial era. We use an open-source, simple climate and carbon cycle model ("Hector") to investigate future changes in ocean acidification (pH and calcium carbonate saturations) under the climate agreement from the United Nations Convention on Climate Change Conference (UNFCCC) of Parties in Paris 2015 (COP 21). Hector is a reduced-form, very fast-executing model that can emulate the global mean climate of the CMIP5 models, as well as the inorganic carbon cycle in the upper ocean, allowing us to investigate future changes in ocean acidification. We ran Hector under three different emissions trajectories, using a sensitivity analysis approach to quantify model uncertainty and capture a range of possible ocean acidification changes. The first trajectory is a business-as-usual scenario comparable to a Representative Concentration Pathway (RCP) 8.5, the second a scenario with the COP 21 commitments enacted, and the third an idealized scenario keeping global temperature change to 2°C, comparable to a RCP 2.6. Preliminary results suggest that under the COP 21 agreements ocean pH at 2100 will decrease by 0.2 units and surface saturations of aragonite (calcite) will decrease by 0.9 (1.4) units relative to 1850. Under the COP 21 agreement the world's oceans will be committed to a degree of ocean acidification, however, these changes may be within the range of natural variability evident in some paleo records.

  16. Importance of ocean salinity for climate and habitability.

    PubMed

    Cullum, Jodie; Stevens, David P; Joshi, Manoj M

    2016-04-19

    Modeling studies of terrestrial extrasolar planetary climates are now including the effects of ocean circulation due to a recognition of the importance of oceans for climate; indeed, the peak equator-pole ocean heat transport on Earth peaks at almost half that of the atmosphere. However, such studies have made the assumption that fundamental oceanic properties, such as salinity, temperature, and depth, are similar to Earth. This assumption results in Earth-like circulations: a meridional overturning with warm water moving poleward at the surface, being cooled, sinking at high latitudes, and traveling equatorward at depth. Here it is shown that an exoplanetary ocean with a different salinity can circulate in the opposite direction: an equatorward flow of polar water at the surface, sinking in the tropics, and filling the deep ocean with warm water. This alternative flow regime results in a dramatic warming in the polar regions, demonstrated here using both a conceptual model and an ocean general circulation model. These results highlight the importance of ocean salinity for exoplanetary climate and consequent habitability and the need for its consideration in future studies.

  17. Atmospheric and Oceanic Response to Southern Ocean Deep Convection Oscillations on Decadal to Centennial Time Scales in Climate Models

    NASA Astrophysics Data System (ADS)

    Martin, T.; Reintges, A.; Park, W.; Latif, M.

    2014-12-01

    Many current coupled global climate models simulate open ocean deep convection in the Southern Ocean as a recurring event with time scales ranging from a few years to centennial (de Lavergne et al., 2014, Nat. Clim. Ch.). The only observation of such event, however, was the occurrence of the Weddell Polynya in the mid-1970s, an open water area of 350 000 km2 within the Antarctic sea ice in three consecutive winters. Both the wide range of modeled frequency of occurrence and the absence of deep convection in the Weddell Sea highlights the lack of understanding concerning the phenomenon. Nevertheless, simulations indicate that atmospheric and oceanic responses to the cessation of deep convection in the Southern Ocean include a strengthening of the low-level atmospheric circulation over the Southern Ocean (increasing SAM index) and a reduction in the export of Antarctic Bottom Water (AABW), potentially masking the regional effects of global warming (Latif et al., 2013, J. Clim.; Martin et al., 2014, Deep Sea Res. II). It is thus of great importance to enhance our understanding of Southern Ocean deep convection and clarify the associated time scales. In two multi-millennial simulations with the Kiel Climate Model (KCM, ECHAM5 T31 atmosphere & NEMO-LIM2 ~2˚ ocean) we showed that the deep convection is driven by strong oceanic warming at mid-depth periodically overriding the stabilizing effects of precipitation and ice melt (Martin et al., 2013, Clim. Dyn.). Sea ice thickness also affects location and duration of the deep convection. A new control simulation, in which, amongst others, the atmosphere grid resolution is changed to T42 (~2.8˚), yields a faster deep convection flip-flop with a period of 80-100 years and a weaker but still significant global climate response similar to CMIP5 simulations. While model physics seem to affect the time scale and intensity of the phenomenon, the driving mechanism is a rather robust feature. Finally, we compare the atmospheric and

  18. Ocean eddies and climate predictability

    NASA Astrophysics Data System (ADS)

    Kirtman, Ben P.; Perlin, Natalie; Siqueira, Leo

    2017-12-01

    A suite of coupled climate model simulations and experiments are used to examine how resolved mesoscale ocean features affect aspects of climate variability, air-sea interactions, and predictability. In combination with control simulations, experiments with the interactive ensemble coupling strategy are used to further amplify the role of the oceanic mesoscale field and the associated air-sea feedbacks and predictability. The basic intent of the interactive ensemble coupling strategy is to reduce the atmospheric noise at the air-sea interface, allowing an assessment of how noise affects the variability, and in this case, it is also used to diagnose predictability from the perspective of signal-to-noise ratios. The climate variability is assessed from the perspective of sea surface temperature (SST) variance ratios, and it is shown that, unsurprisingly, mesoscale variability significantly increases SST variance. Perhaps surprising is the fact that the presence of mesoscale ocean features even further enhances the SST variance in the interactive ensemble simulation beyond what would be expected from simple linear arguments. Changes in the air-sea coupling between simulations are assessed using pointwise convective rainfall-SST and convective rainfall-SST tendency correlations and again emphasize how the oceanic mesoscale alters the local association between convective rainfall and SST. Understanding the possible relationships between the SST-forced signal and the weather noise is critically important in climate predictability. We use the interactive ensemble simulations to diagnose this relationship, and we find that the presence of mesoscale ocean features significantly enhances this link particularly in ocean eddy rich regions. Finally, we use signal-to-noise ratios to show that the ocean mesoscale activity increases model estimated predictability in terms of convective precipitation and atmospheric upper tropospheric circulation.

  19. Ocean eddies and climate predictability.

    PubMed

    Kirtman, Ben P; Perlin, Natalie; Siqueira, Leo

    2017-12-01

    A suite of coupled climate model simulations and experiments are used to examine how resolved mesoscale ocean features affect aspects of climate variability, air-sea interactions, and predictability. In combination with control simulations, experiments with the interactive ensemble coupling strategy are used to further amplify the role of the oceanic mesoscale field and the associated air-sea feedbacks and predictability. The basic intent of the interactive ensemble coupling strategy is to reduce the atmospheric noise at the air-sea interface, allowing an assessment of how noise affects the variability, and in this case, it is also used to diagnose predictability from the perspective of signal-to-noise ratios. The climate variability is assessed from the perspective of sea surface temperature (SST) variance ratios, and it is shown that, unsurprisingly, mesoscale variability significantly increases SST variance. Perhaps surprising is the fact that the presence of mesoscale ocean features even further enhances the SST variance in the interactive ensemble simulation beyond what would be expected from simple linear arguments. Changes in the air-sea coupling between simulations are assessed using pointwise convective rainfall-SST and convective rainfall-SST tendency correlations and again emphasize how the oceanic mesoscale alters the local association between convective rainfall and SST. Understanding the possible relationships between the SST-forced signal and the weather noise is critically important in climate predictability. We use the interactive ensemble simulations to diagnose this relationship, and we find that the presence of mesoscale ocean features significantly enhances this link particularly in ocean eddy rich regions. Finally, we use signal-to-noise ratios to show that the ocean mesoscale activity increases model estimated predictability in terms of convective precipitation and atmospheric upper tropospheric circulation.

  20. The Impact of Ocean Observations in Seasonal Climate Prediction

    NASA Technical Reports Server (NTRS)

    Rienecker, Michele; Keppenne, Christian; Kovach, Robin; Marshak, Jelena

    2010-01-01

    The ocean provides the most significant memory for the climate system. Hence, a critical element in climate forecasting with coupled models is the initialization of the ocean with states from an ocean data assimilation system. Remotely-sensed ocean surface fields (e.g., sea surface topography, SST, winds) are now available for extensive periods and have been used to constrain ocean models to provide a record of climate variations. Since the ocean is virtually opaque to electromagnetic radiation, the assimilation of these satellite data is essential to extracting the maximum information content. More recently, the Argo drifters have provided unprecedented sampling of the subsurface temperature and salinity. Although the duration of this observation set has been too short to provide solid statistical evidence of its impact, there are indications that Argo improves the forecast skill of coupled systems. This presentation will address the impact these different observations have had on seasonal climate predictions with the GMAO's coupled model.

  1. Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

    NASA Astrophysics Data System (ADS)

    Williams, Paul; Howe, Nicola; Gregory, Jonathan; Smith, Robin; Joshi, Manoj

    2017-04-01

    In climate simulations, the impacts of the subgrid scales on the resolved scales are conventionally represented using deterministic closure schemes, which assume that the impacts are uniquely determined by the resolved scales. Stochastic parameterization relaxes this assumption, by sampling the subgrid variability in a computationally inexpensive manner. This study shows that the simulated climatological state of the ocean is improved in many respects by implementing a simple stochastic parameterization of ocean eddies into a coupled atmosphere-ocean general circulation model. Simulations from a high-resolution, eddy-permitting ocean model are used to calculate the eddy statistics needed to inject realistic stochastic noise into a low-resolution, non-eddy-permitting version of the same model. A suite of four stochastic experiments is then run to test the sensitivity of the simulated climate to the noise definition by varying the noise amplitude and decorrelation time within reasonable limits. The addition of zero-mean noise to the ocean temperature tendency is found to have a nonzero effect on the mean climate. Specifically, in terms of the ocean temperature and salinity fields both at the surface and at depth, the noise reduces many of the biases in the low-resolution model and causes it to more closely resemble the high-resolution model. The variability of the strength of the global ocean thermohaline circulation is also improved. It is concluded that stochastic ocean perturbations can yield reductions in climate model error that are comparable to those obtained by refining the resolution, but without the increased computational cost. Therefore, stochastic parameterizations of ocean eddies have the potential to significantly improve climate simulations. Reference Williams PD, Howe NJ, Gregory JM, Smith RS, and Joshi MM (2016) Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies. Journal of Climate, 29, 8763-8781. http://dx.doi.org/10

  2. Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

    NASA Astrophysics Data System (ADS)

    Williams, Paul; Howe, Nicola; Gregory, Jonathan; Smith, Robin; Joshi, Manoj

    2016-04-01

    In climate simulations, the impacts of the sub-grid scales on the resolved scales are conventionally represented using deterministic closure schemes, which assume that the impacts are uniquely determined by the resolved scales. Stochastic parameterization relaxes this assumption, by sampling the sub-grid variability in a computationally inexpensive manner. This presentation shows that the simulated climatological state of the ocean is improved in many respects by implementing a simple stochastic parameterization of ocean eddies into a coupled atmosphere-ocean general circulation model. Simulations from a high-resolution, eddy-permitting ocean model are used to calculate the eddy statistics needed to inject realistic stochastic noise into a low-resolution, non-eddy-permitting version of the same model. A suite of four stochastic experiments is then run to test the sensitivity of the simulated climate to the noise definition, by varying the noise amplitude and decorrelation time within reasonable limits. The addition of zero-mean noise to the ocean temperature tendency is found to have a non-zero effect on the mean climate. Specifically, in terms of the ocean temperature and salinity fields both at the surface and at depth, the noise reduces many of the biases in the low-resolution model and causes it to more closely resemble the high-resolution model. The variability of the strength of the global ocean thermohaline circulation is also improved. It is concluded that stochastic ocean perturbations can yield reductions in climate model error that are comparable to those obtained by refining the resolution, but without the increased computational cost. Therefore, stochastic parameterizations of ocean eddies have the potential to significantly improve climate simulations. Reference PD Williams, NJ Howe, JM Gregory, RS Smith, and MM Joshi (2016) Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies. Journal of Climate, under revision.

  3. Ocean-Atmosphere Interactions Modulate Irrigation's Climate Impacts

    NASA Technical Reports Server (NTRS)

    Krakauer, Nir Y.; Puma, Michael J.; Cook, Benjamin I.; Gentine, Pierre; Nazarenko, Larissa

    2016-01-01

    Numerous studies have focused on the local and regional climate effects of irrigated agriculture and other land cover and land use change (LCLUC) phenomena, but there are few studies on the role of ocean- atmosphere interaction in modulating irrigation climate impacts. Here, we compare simulations with and without interactive sea surface temperatures of the equilibrium effect on climate of contemporary (year 2000) irrigation geographic extent and intensity. We find that ocean-atmosphere interaction does impact the magnitude of global-mean and spatially varying climate impacts, greatly increasing their global reach. Local climate effects in the irrigated regions remain broadly similar, while non-local effects, particularly over the oceans, tend to be larger. The interaction amplifies irrigation-driven standing wave patterns in the tropics and mid-latitudes in our simulations, approximately doubling the global-mean amplitude of surface temperature changes due to irrigation. The fractions of global area experiencing significant annual-mean surface air temperature and precipitation change also approximately double with ocean-atmosphere interaction. Subject to confirmation with other models, these findings imply that LCLUC is an important contributor to climate change even in remote areas such as the Southern Ocean, and that attribution studies should include interactive oceans and need to consider LCLUC, including irrigation, as a truly global forcing that affects climate and the water cycle over ocean as well as land areas.

  4. Importance of ocean salinity for climate and habitability

    PubMed Central

    Cullum, Jodie; Stevens, David P.; Joshi, Manoj M.

    2016-01-01

    Modeling studies of terrestrial extrasolar planetary climates are now including the effects of ocean circulation due to a recognition of the importance of oceans for climate; indeed, the peak equator-pole ocean heat transport on Earth peaks at almost half that of the atmosphere. However, such studies have made the assumption that fundamental oceanic properties, such as salinity, temperature, and depth, are similar to Earth. This assumption results in Earth-like circulations: a meridional overturning with warm water moving poleward at the surface, being cooled, sinking at high latitudes, and traveling equatorward at depth. Here it is shown that an exoplanetary ocean with a different salinity can circulate in the opposite direction: an equatorward flow of polar water at the surface, sinking in the tropics, and filling the deep ocean with warm water. This alternative flow regime results in a dramatic warming in the polar regions, demonstrated here using both a conceptual model and an ocean general circulation model. These results highlight the importance of ocean salinity for exoplanetary climate and consequent habitability and the need for its consideration in future studies. PMID:27044090

  5. Understanding Climate Uncertainty with an Ocean Focus

    NASA Astrophysics Data System (ADS)

    Tokmakian, R. T.

    2009-12-01

    Uncertainty in climate simulations arises from various aspects of the end-to-end process of modeling the Earth’s climate. First, there is uncertainty from the structure of the climate model components (e.g. ocean/ice/atmosphere). Even the most complex models are deficient, not only in the complexity of the processes they represent, but in which processes are included in a particular model. Next, uncertainties arise from the inherent error in the initial and boundary conditions of a simulation. Initial conditions are the state of the weather or climate at the beginning of the simulation and other such things, and typically come from observations. Finally, there is the uncertainty associated with the values of parameters in the model. These parameters may represent physical constants or effects, such as ocean mixing, or non-physical aspects of modeling and computation. The uncertainty in these input parameters propagates through the non-linear model to give uncertainty in the outputs. The models in 2020 will no doubt be better than today’s models, but they will still be imperfect, and development of uncertainty analysis technology is a critical aspect of understanding model realism and prediction capability. Smith [2002] and Cox and Stephenson [2007] discuss the need for methods to quantify the uncertainties within complicated systems so that limitations or weaknesses of the climate model can be understood. In making climate predictions, we need to have available both the most reliable model or simulation and a methods to quantify the reliability of a simulation. If quantitative uncertainty questions of the internal model dynamics are to be answered with complex simulations such as AOGCMs, then the only known path forward is based on model ensembles that characterize behavior with alternative parameter settings [e.g. Rougier, 2007]. The relevance and feasibility of using "Statistical Analysis of Computer Code Output" (SACCO) methods for examining uncertainty in

  6. The seasonal response of the Held-Suarez climate model to prescribed ocean temperature anomalies. I - Results of decadal integrations

    NASA Technical Reports Server (NTRS)

    Phillips, T. J.; Semtner, A. J., Jr.

    1984-01-01

    Anomalies in ocean surface temperature have been identified as possible causes of variations in the climate of particular seasons or as a source of interannual climatic variability, and attempts have been made to forecast seasonal climate by using ocean temperatures as predictor variables. However, the seasonal atmospheric response to ocean temperature anomalies has not yet been systematically investigated with nonlinear models. The present investigation is concerned with ten-year integrations involving a model of intermediate complexity, the Held-Suarez climate model. The calculations have been performed to investigate the changes in seasonal climate which result from a fixed anomaly imposed on a seasonally varying, global ocean temperature field. Part I of the paper provides a report on the results of these decadal integrations. Attention is given to model properties, the experimental design, and the anomaly experiments.

  7. Chapter 1. Impacts of the oceans on climate change.

    PubMed

    Reid, Philip C; Fischer, Astrid C; Lewis-Brown, Emily; Meredith, Michael P; Sparrow, Mike; Andersson, Andreas J; Antia, Avan; Bates, Nicholas R; Bathmann, Ulrich; Beaugrand, Gregory; Brix, Holger; Dye, Stephen; Edwards, Martin; Furevik, Tore; Gangstø, Reidun; Hátún, Hjálmar; Hopcroft, Russell R; Kendall, Mike; Kasten, Sabine; Keeling, Ralph; Le Quéré, Corinne; Mackenzie, Fred T; Malin, Gill; Mauritzen, Cecilie; Olafsson, Jón; Paull, Charlie; Rignot, Eric; Shimada, Koji; Vogt, Meike; Wallace, Craig; Wang, Zhaomin; Washington, Richard

    2009-01-01

    further releases of the potent greenhouse gas methane from hydrates and permafrost. The Southern Ocean plays a critical role in driving, modifying and regulating global climate change via the carbon cycle and through its impact on adjacent Antarctica. The Antarctic Peninsula has shown some of the most rapid rises in atmospheric and oceanic temperature in the world, with an associated retreat of the majority of glaciers. Parts of the West Antarctic ice sheet are deflating rapidly, very likely due to a change in the flux of oceanic heat to the undersides of the floating ice shelves. The final section on modelling feedbacks from the ocean to climate change identifies limitations and priorities for model development and associated observations. Considering the importance of the oceans to climate change and our limited understanding of climate-related ocean processes, our ability to measure the changes that are taking place are conspicuously inadequate. The chapter highlights the need for a comprehensive, adequately funded and globally extensive ocean observing system to be implemented and sustained as a high priority. Unless feedbacks from the oceans to climate change are adequately included in climate change models, it is possible that the mitigation actions needed to stabilise CO2 and limit temperature rise over the next century will be underestimated.

  8. Wave–turbulence interaction-induced vertical mixing and its effects in ocean and climate models

    PubMed Central

    Qiao, Fangli; Yuan, Yeli; Deng, Jia; Dai, Dejun; Song, Zhenya

    2016-01-01

    Heated from above, the oceans are stably stratified. Therefore, the performance of general ocean circulation models and climate studies through coupled atmosphere–ocean models depends critically on vertical mixing of energy and momentum in the water column. Many of the traditional general circulation models are based on total kinetic energy (TKE), in which the roles of waves are averaged out. Although theoretical calculations suggest that waves could greatly enhance coexisting turbulence, no field measurements on turbulence have ever validated this mechanism directly. To address this problem, a specially designed field experiment has been conducted. The experimental results indicate that the wave–turbulence interaction-induced enhancement of the background turbulence is indeed the predominant mechanism for turbulence generation and enhancement. Based on this understanding, we propose a new parametrization for vertical mixing as an additive part to the traditional TKE approach. This new result reconfirmed the past theoretical model that had been tested and validated in numerical model experiments and field observations. It firmly establishes the critical role of wave–turbulence interaction effects in both general ocean circulation models and atmosphere–ocean coupled models, which could greatly improve the understanding of the sea surface temperature and water column properties distributions, and hence model-based climate forecasting capability. PMID:26953182

  9. The Coordinated Ocean Wave Climate Project

    NASA Astrophysics Data System (ADS)

    Hemer, Mark; Dobrynin, Mikhail; Erikson, Li; Lionello, Piero; Mori, Nobuhito; Semedo, Alvaro; Wang, Xiaolan

    2016-04-01

    Future 21st Century changes in wind-wave climate have broad implications for marine and coastal infrastructure and ecosystems. Atmosphere-ocean general circulation models (GCM) are now routinely used for assessing and providing future projections of climatological parameters such as temperature and precipitation, but generally these provide no information on ocean wind-waves. To fill this information gap a growing number of studies are using GCM outputs and independently producing global and regional scale wind-wave climate projections. Furthermore, additional studies are actively coupling wind-wave dependent atmosphere-ocean exchanges into GCMs, to improve physical representation and quantify the impact of waves in the coupled climate system, and can also deliver wave characteristics as another variable in the climate system. To consolidate these efforts, understand the sources of variance between projections generated by different methodologies and International groups, and ultimately provide a robust picture of the role of wind-waves in the climate system and their projected changes, we present outcomes of the JCOMM supported Coordinated Ocean Wave Climate Project (COWCLIP). The objective of COWCLIP is twofold: to make community based ensembles of wave climate projections openly accessible, to provide the necessary information to support diligent marine and coastal impacts of climate change studies; and to understand the effects and feedback influences of wind-waves in the coupled ocean-atmosphere climate system. We will present the current status of COWCLIP, providing an overview of the objectives, analysis and results of the initial phase - now complete - and the progress of ongoing phases of the project.

  10. Tropical Atlantic climate response to different freshwater input in high latitudes with an ocean-only general circulation model

    NASA Astrophysics Data System (ADS)

    Men, Guang; Wan, Xiuquan; Liu, Zedong

    2016-10-01

    Tropical Atlantic climate change is relevant to the variation of Atlantic meridional overturning circulation (AMOC) through different physical processes. Previous coupled climate model simulation suggested a dipole-like SST structure cooling over the North Atlantic and warming over the South Tropical Atlantic in response to the slowdown of the AMOC. Using an ocean-only global ocean model here, an attempt was made to separate the total influence of various AMOC change scenarios into an oceanic-induced component and an atmospheric-induced component. In contrast with previous freshwater-hosing experiments with coupled climate models, the ocean-only modeling presented here shows a surface warming in the whole tropical Atlantic region and the oceanic-induced processes may play an important role in the SST change in the equatorial south Atlantic. Our result shows that the warming is partly governed by oceanic process through the mechanism of oceanic gateway change, which operates in the regime where freshwater forcing is strong, exceeding 0.3 Sv. Strong AMOC change is required for the gateway mechanism to work in our model because only when the AMOC is sufficiently weak, the North Brazil Undercurrent can flow equatorward, carrying warm and salty north Atlantic subtropical gyre water into the equatorial zone. This threshold is likely to be model-dependent. An improved understanding of these issues may have help with abrupt climate change prediction later.

  11. Integrating Climate and Ocean Change Vulnerability into Conservation Planning

    NASA Astrophysics Data System (ADS)

    Mcleod, E.; Green, A.; Game, E.; Anthony, K.; Cinner, J.; Heron, S. F.; Kleypas, J. A.; Lovelock, C.; Pandolfi, J.; Pressey, B.; Salm, R.; Schill, S.; Woodroffe, C. D.

    2013-05-01

    Tropical coastal and marine ecosystems are particularly vulnerable to ocean warming, ocean acidification, and sea-level rise. Yet these projected climate and ocean change impacts are rarely considered in conservation planning due to the lack of guidance on how existing climate and ocean change models, tools, and data can be applied. We address this gap by describing how conservation planning can use available tools and data for assessing the vulnerability of tropical marine ecosystems to key climate threats. Additionally, we identify limitations of existing tools and provide recommendations for future research to improve integration of climate and ocean change information and conservation planning. Such information is critical for developing a conservation response that adequately protects these ecosystems and dependent coastal communities in the face of climate and ocean change.

  12. Ocean state estimation for climate studies

    NASA Technical Reports Server (NTRS)

    Lee, T.

    2002-01-01

    Climate variabilities, which are of interest to CLIVAR, involve a broad range of spatial and temporal scales. Ocean state estimation (often referred to as ocean data assimilation), by optimally combining observations and models, becomes an important element of CLIVAR.

  13. An ocean dynamical thermostat—dominant in observations, absent in climate models

    NASA Astrophysics Data System (ADS)

    Coats, S.; Karnauskas, K. B.

    2016-12-01

    The pattern of sea surface temperature (SST) in the tropical Pacific Ocean is coupled to the Walker circulation, necessitating an understanding of how this pattern will change in response to anthropogenic radiative forcing. State-of-the-art climate models from the Coupled Model Intercomparison Project phase 5 (CMIP5) overwhelmingly project a decrease in the tropical Pacific zonal SST gradient over the coming century. This decrease in the zonal SST gradient is a response of the ocean to a weakening Walker circulation in the CMIP5 models, a consequence of the mass and energy balances of the hydrologic cycle identified by Held and Soden (2006). CMIP5 models, however, are not able to reproduce the observed increase in the zonal SST gradient between 1900-2013 C.E., which we argue to be robust using advanced statistical techniques and new observational datasets. While the observed increase in the zonal SST gradient is suggestive of the ocean dynamical thermostat mechanism of Clement et al. (1996), a strengthening Equatorial Undercurrent (EUC) also contributes to eastern equatorial Pacific cooling. Importantly, the strengthening EUC is a response of the ocean to a seasonal weakening of the Walker circulation and thus can reconcile disparate observations of changes to the atmosphere and ocean in the equatorial Pacific. CMIP5 models do not capture the magnitude of this response of the EUC to anthropogenic radiative forcing potentially because of biases in the sensitivity of the EUC to changes in zonal wind stress, like the weakening Walker circulation. Consequently, they project a continuation of the opposite to what has been observed in the real world, with potentially serious consequences for projected climate impacts that are influenced by the tropical Pacific.

  14. Carbon-climate feedbacks accelerate ocean acidification

    NASA Astrophysics Data System (ADS)

    Matear, Richard J.; Lenton, Andrew

    2018-03-01

    Carbon-climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO2 concentrations (Zaehle et al. 2010). By modifying the future atmospheric CO2 concentrations, the carbon-climate feedbacks will also influence the future ocean acidification trajectory. Here, we use the CO2 emissions scenarios from four representative concentration pathways (RCPs) with an Earth system model to project the future trajectories of ocean acidification with the inclusion of carbon-climate feedbacks. We show that simulated carbon-climate feedbacks can significantly impact the onset of undersaturated aragonite conditions in the Southern and Arctic oceans, the suitable habitat for tropical coral and the deepwater saturation states. Under the high-emissions scenarios (RCP8.5 and RCP6), the carbon-climate feedbacks advance the onset of surface water under saturation and the decline in suitable coral reef habitat by a decade or more. The impacts of the carbon-climate feedbacks are most significant for the medium- (RCP4.5) and low-emissions (RCP2.6) scenarios. For the RCP4.5 scenario, by 2100 the carbon-climate feedbacks nearly double the area of surface water undersaturated with respect to aragonite and reduce by 50 % the surface water suitable for coral reefs. For the RCP2.6 scenario, by 2100 the carbon-climate feedbacks reduce the area suitable for coral reefs by 40 % and increase the area of undersaturated surface water by 20 %. The sensitivity of ocean acidification to the carbon-climate feedbacks in the low to medium emission scenarios is important because recent CO2 emission reduction commitments are trying to transition emissions to such a scenario. Our study highlights the need to better characterise the carbon-climate feedbacks and ensure we do not underestimate the projected ocean acidification.

  15. Global Climate Impacts of Fixing the Southern Ocean Shortwave Radiation Bias in the Community Earth System Model (CESM)

    SciTech Connect

    Kay, Jennifer E.; Wall, Casey; Yettella, Vineel

    Here, a large, long-standing, and pervasive climate model bias is excessive absorbed shortwave radiation (ASR) over the midlatitude oceans, especially the Southern Ocean. This study investigates both the underlying mechanisms for and climate impacts of this bias within the Community Earth System Model, version 1, with the Community Atmosphere Model, version 5 [CESM1(CAM5)]. Excessive Southern Ocean ASR in CESM1(CAM5) results in part because low-level clouds contain insufficient amounts of supercooled liquid. In a present-day atmosphere-only run, an observationally motivated modification to the shallow convection detrainment increases supercooled cloud liquid, brightens low-level clouds, and substantially reduces the Southern Ocean ASR bias.more » Tuning to maintain global energy balance enables reduction of a compensating tropical ASR bias. In the resulting preindustrial fully coupled run with a brighter Southern Ocean and dimmer tropics, the Southern Ocean cools and the tropics warm. As a result of the enhanced meridional temperature gradient, poleward heat transport increases in both hemispheres (especially the Southern Hemisphere), and the Southern Hemisphere atmospheric jet strengthens. Because northward cross-equatorial heat transport reductions occur primarily in the ocean (80%), not the atmosphere (20%), a proposed atmospheric teleconnection linking Southern Ocean ASR bias reduction and cooling with northward shifts in tropical precipitation has little impact. In summary, observationally motivated supercooled liquid water increases in shallow convective clouds enable large reductions in long-standing climate model shortwave radiation biases. Of relevance to both model bias reduction and climate dynamics, quantifying the influence of Southern Ocean cooling on tropical precipitation requires a model with dynamic ocean heat transport.« less

  16. Global Climate Impacts of Fixing the Southern Ocean Shortwave Radiation Bias in the Community Earth System Model (CESM)

    DOE PAGES

    Kay, Jennifer E.; Wall, Casey; Yettella, Vineel; ...

    2016-06-10

    Here, a large, long-standing, and pervasive climate model bias is excessive absorbed shortwave radiation (ASR) over the midlatitude oceans, especially the Southern Ocean. This study investigates both the underlying mechanisms for and climate impacts of this bias within the Community Earth System Model, version 1, with the Community Atmosphere Model, version 5 [CESM1(CAM5)]. Excessive Southern Ocean ASR in CESM1(CAM5) results in part because low-level clouds contain insufficient amounts of supercooled liquid. In a present-day atmosphere-only run, an observationally motivated modification to the shallow convection detrainment increases supercooled cloud liquid, brightens low-level clouds, and substantially reduces the Southern Ocean ASR bias.more » Tuning to maintain global energy balance enables reduction of a compensating tropical ASR bias. In the resulting preindustrial fully coupled run with a brighter Southern Ocean and dimmer tropics, the Southern Ocean cools and the tropics warm. As a result of the enhanced meridional temperature gradient, poleward heat transport increases in both hemispheres (especially the Southern Hemisphere), and the Southern Hemisphere atmospheric jet strengthens. Because northward cross-equatorial heat transport reductions occur primarily in the ocean (80%), not the atmosphere (20%), a proposed atmospheric teleconnection linking Southern Ocean ASR bias reduction and cooling with northward shifts in tropical precipitation has little impact. In summary, observationally motivated supercooled liquid water increases in shallow convective clouds enable large reductions in long-standing climate model shortwave radiation biases. Of relevance to both model bias reduction and climate dynamics, quantifying the influence of Southern Ocean cooling on tropical precipitation requires a model with dynamic ocean heat transport.« less

  17. Collaborative Project. Understanding the effects of tides and eddies on the ocean dynamics, sea ice cover and decadal/centennial climate prediction using the Regional Arctic Climate Model (RACM)

    SciTech Connect

    Hutchings, Jennifer; Joseph, Renu

    2013-09-14

    The goal of this project is to develop an eddy resolving ocean model (POP) with tides coupled to a sea ice model (CICE) within the Regional Arctic System Model (RASM) to investigate the importance of ocean tides and mesoscale eddies in arctic climate simulations and quantify biases associated with these processes and how their relative contribution may improve decadal to centennial arctic climate predictions. Ocean, sea ice and coupled arctic climate response to these small scale processes will be evaluated with regard to their influence on mass, momentum and property exchange between oceans, shelf-basin, ice-ocean, and ocean-atmosphere. The project willmore » facilitate the future routine inclusion of polar tides and eddies in Earth System Models when computing power allows. As such, the proposed research addresses the science in support of the BER’s Climate and Environmental Sciences Division Long Term Measure as it will improve the ocean and sea ice model components as well as the fully coupled RASM and Community Earth System Model (CESM) and it will make them more accurate and computationally efficient.« less

  18. Biased thermohaline exchanges with the Arctic across the Iceland-Faroe Ridge in ocean climate models

    NASA Astrophysics Data System (ADS)

    Olsen, S. M.; Hansen, B.; Østerhus, S.; Quadfasel, D.; Valdimarsson, H.

    2016-04-01

    The northern limb of the Atlantic thermohaline circulation and its transport of heat and salt towards the Arctic strongly modulate the climate of the Northern Hemisphere. The presence of warm surface waters prevents ice formation in parts of the Arctic Mediterranean, and ocean heat is directly available for sea-ice melt, while salt transport may be critical for the stability of the exchanges. Through these mechanisms, ocean heat and salt transports play a disproportionally strong role in the climate system, and realistic simulation is a requisite for reliable climate projections. Across the Greenland-Scotland Ridge (GSR) this occurs in three well-defined branches where anomalies in the warm and saline Atlantic inflow across the shallow Iceland-Faroe Ridge (IFR) have been shown to be particularly difficult to simulate in global ocean models. This branch (IF-inflow) carries about 40 % of the total ocean heat transport into the Arctic Mediterranean and is well constrained by observation during the last 2 decades but associated with significant inter-annual fluctuations. The inconsistency between model results and observational data is here explained by the inability of coarse-resolution models to simulate the overflow across the IFR (IF-overflow), which feeds back onto the simulated IF-inflow. In effect, this is reduced in the model to reflect only the net exchange across the IFR. Observational evidence is presented for a substantial and persistent IF-overflow and mechanisms that qualitatively control its intensity. Through this, we explain the main discrepancies between observed and simulated exchange. Our findings rebuild confidence in modelled net exchange across the IFR, but reveal that compensation of model deficiencies here through other exchange branches is not effective. This implies that simulated ocean heat transport to the Arctic is biased low by more than 10 % and associated with a reduced level of variability, while the quality of the simulated salt

  19. Ocean angular momentum signals in a climate model and implications for Earth rotation

    NASA Astrophysics Data System (ADS)

    Ponte, R. M.; Rajamony, J.; Gregory, J. M.

    2002-03-01

    Estimates of ocean angular momentum (OAM) provide an integrated measure of variability in ocean circulation and mass fields and can be directly related to observed changes in Earth rotation. We use output from a climate model to calculate 240 years of 3-monthly OAM values (two equatorial terms L1 and L2, related to polar motion or wobble, and axial term L3, related to length of day variations) representing the period 1860-2100. Control and forced runs permit the study of the effects of natural and anthropogenically forced climate variability on OAM. All OAM components exhibit a clear annual cycle, with large decadal modulations in amplitude, and also longer period fluctuations, all associated with natural climate variability in the model. Anthropogenically induced signals, inferred from the differences between forced and control runs, include an upward trend in L3, related to inhomogeneous ocean warming and increases in the transport of the Antarctic Circumpolar Current, and a significantly weaker seasonal cycle in L2 in the second half of the record, related primarily to changes in seasonal bottom pressure variability in the Southern Ocean and North Pacific. Variability in mass fields is in general more important to OAM signals than changes in circulation at the seasonal and longer periods analyzed. Relation of OAM signals to changes in surface atmospheric forcing are discussed. The important role of the oceans as an excitation source for the annual, Chandler and Markowitz wobbles, is confirmed. Natural climate variability in OAM and related excitation is likely to measurably affect the Earth rotation, but anthropogenically induced effects are comparatively weak.

  20. Natural ocean carbon cycle sensitivity to parameterizations of the recycling in a climate model

    NASA Astrophysics Data System (ADS)

    Romanou, A.; Romanski, J.; Gregg, W. W.

    2014-02-01

    Sensitivities of the oceanic biological pump within the GISS (Goddard Institute for Space Studies ) climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM), which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. GISSEH(GISSER) is found to underestimate mixed layer depth compared to observations by about 55% (10%) in the Southern Ocean and overestimate it by about 17% (underestimate by 2%) in the northern high latitudes. Everywhere else in the global ocean, the two models underestimate the surface mixing by about 12-34%, which prevents deep nutrients from reaching the surface and promoting primary production there. Consequently, carbon export is reduced because of reduced production at the surface. Furthermore, carbon export is particularly sensitive to remineralization rate changes in the frontal regions of the subtropical gyres and at the Equator and this sensitivity in the model is much higher than the sensitivity to physical processes such as vertical mixing, vertical advection and mesoscale eddy transport. At depth, GISSER, which has a significant warm bias, remineralizes nutrients and carbon faster thereby producing more nutrients and carbon at depth, which

  1. Natural Ocean Carbon Cycle Sensitivity to Parameterizations of the Recycling in a Climate Model

    NASA Technical Reports Server (NTRS)

    Romanou, A.; Romanski, J.; Gregg, W. W.

    2014-01-01

    Sensitivities of the oceanic biological pump within the GISS (Goddard Institute for Space Studies ) climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM), which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. GISSEH(GISSER) is found to underestimate mixed layer depth compared to observations by about 55% (10 %) in the Southern Ocean and overestimate it by about 17% (underestimate by 2%) in the northern high latitudes. Everywhere else in the global ocean, the two models underestimate the surface mixing by about 12-34 %, which prevents deep nutrients from reaching the surface and promoting primary production there. Consequently, carbon export is reduced because of reduced production at the surface. Furthermore, carbon export is particularly sensitive to remineralization rate changes in the frontal regions of the subtropical gyres and at the Equator and this sensitivity in the model is much higher than the sensitivity to physical processes such as vertical mixing, vertical advection and mesoscale eddy transport. At depth, GISSER, which has a significant warm bias, remineralizes nutrients and carbon faster thereby producing more nutrients and carbon at depth, which

  2. Decadal climate predictions improved by ocean ensemble dispersion filtering

    NASA Astrophysics Data System (ADS)

    Kadow, C.; Illing, S.; Kröner, I.; Ulbrich, U.; Cubasch, U.

    2017-06-01

    Decadal predictions by Earth system models aim to capture the state and phase of the climate several years in advance. Atmosphere-ocean interaction plays an important role for such climate forecasts. While short-term weather forecasts represent an initial value problem and long-term climate projections represent a boundary condition problem, the decadal climate prediction falls in-between these two time scales. In recent years, more precise initialization techniques of coupled Earth system models and increased ensemble sizes have improved decadal predictions. However, climate models in general start losing the initialized signal and its predictive skill from one forecast year to the next. Here we show that the climate prediction skill of an Earth system model can be improved by a shift of the ocean state toward the ensemble mean of its individual members at seasonal intervals. We found that this procedure, called ensemble dispersion filter, results in more accurate results than the standard decadal prediction. Global mean and regional temperature, precipitation, and winter cyclone predictions show an increased skill up to 5 years ahead. Furthermore, the novel technique outperforms predictions with larger ensembles and higher resolution. Our results demonstrate how decadal climate predictions benefit from ocean ensemble dispersion filtering toward the ensemble mean.Plain Language SummaryDecadal predictions aim to predict the <span class="hlt">climate</span> several years in advance. Atmosphere-<span class="hlt">ocean</span> interaction plays an important role for such <span class="hlt">climate</span> forecasts. The <span class="hlt">ocean</span> memory due to its heat capacity holds big potential skill. In recent years, more precise initialization techniques of coupled Earth system <span class="hlt">models</span> (incl. atmosphere and <span class="hlt">ocean</span>) have improved decadal predictions. Ensembles are another important aspect. Applying slightly perturbed predictions to trigger the famous butterfly effect results in an ensemble. Instead of evaluating one</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26473335','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26473335"><span><span class="hlt">Ocean</span> Data Assimilation in Support of <span class="hlt">Climate</span> Applications: Status and Perspectives.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stammer, D; Balmaseda, M; Heimbach, P; Köhl, A; Weaver, A</p> <p>2016-01-01</p> <p><span class="hlt">Ocean</span> data assimilation brings together observations with known dynamics encapsulated in a circulation <span class="hlt">model</span> to describe the time-varying <span class="hlt">ocean</span> circulation. Its applications are manifold, ranging from marine and ecosystem forecasting to <span class="hlt">climate</span> prediction and studies of the carbon cycle. Here, we address only <span class="hlt">climate</span> applications, which range from improving our understanding of <span class="hlt">ocean</span> circulation to estimating initial or boundary conditions and <span class="hlt">model</span> parameters for <span class="hlt">ocean</span> and <span class="hlt">climate</span> forecasts. Because of differences in underlying methodologies, data assimilation products must be used judiciously and selected according to the specific purpose, as not all related inferences would be equally reliable. Further advances are expected from improved <span class="hlt">models</span> and methods for estimating and representing error information in data assimilation systems. Ultimately, data assimilation into coupled <span class="hlt">climate</span> system components is needed to support <span class="hlt">ocean</span> and <span class="hlt">climate</span> services. However, maintaining the infrastructure and expertise for sustained data assimilation remains challenging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OcMod.120..120H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OcMod.120..120H"><span>Will high-resolution global <span class="hlt">ocean</span> <span class="hlt">models</span> benefit coupled predictions on short-range to <span class="hlt">climate</span> timescales?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hewitt, Helene T.; Bell, Michael J.; Chassignet, Eric P.; Czaja, Arnaud; Ferreira, David; Griffies, Stephen M.; Hyder, Pat; McClean, Julie L.; New, Adrian L.; Roberts, Malcolm J.</p> <p>2017-12-01</p> <p>As the importance of the <span class="hlt">ocean</span> in the weather and <span class="hlt">climate</span> system is increasingly recognised, operational systems are now moving towards coupled prediction not only for seasonal to <span class="hlt">climate</span> timescales but also for short-range forecasts. A three-way tension exists between the allocation of computing resources to refine <span class="hlt">model</span> resolution, the expansion of <span class="hlt">model</span> complexity/capability, and the increase of ensemble size. Here we review evidence for the benefits of increased <span class="hlt">ocean</span> resolution in global coupled <span class="hlt">models</span>, where the <span class="hlt">ocean</span> component explicitly represents transient mesoscale eddies and narrow boundary currents. We consider lessons learned from forced <span class="hlt">ocean</span>/sea-ice simulations; from studies concerning the SST resolution required to impact atmospheric simulations; and from coupled predictions. Impacts of the mesoscale <span class="hlt">ocean</span> in western boundary current regions on the large-scale atmospheric state have been identified. Understanding of air-sea feedback in western boundary currents is modifying our view of the dynamics in these key regions. It remains unclear whether variability associated with open <span class="hlt">ocean</span> mesoscale eddies is equally important to the large-scale atmospheric state. We include a discussion of what processes can presently be parameterised in coupled <span class="hlt">models</span> with coarse resolution non-eddying <span class="hlt">ocean</span> <span class="hlt">models</span>, and where parameterizations may fall short. We discuss the benefits of resolution and identify gaps in the current literature that leave important questions unanswered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22732501C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22732501C"><span><span class="hlt">Ocean</span> Observations of <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chambers, Don</p> <p>2016-01-01</p> <p>The <span class="hlt">ocean</span> influences <span class="hlt">climate</span> by storing and transporting large amounts of heat, freshwater, and carbon, and exchanging these properties with the atmosphere. About 93% of the excess heat energy stored by the earth over the last 50 years is found in the <span class="hlt">ocean</span>. More than three quarters of the total exchange of water between the atmosphere and the earth's surface through evaporation and precipitation takes place over the <span class="hlt">oceans</span>. The <span class="hlt">ocean</span> contains 50 times more carbon than the atmosphere and is at present acting to slow the rate of <span class="hlt">climate</span> change by absorbing one quarter of human emissions of carbon dioxide from fossil fuel burning, cement production, deforestation and other land use change.Here I summarize the observational evidence of change in the <span class="hlt">ocean</span>, with an emphasis on basin- and global-scale changes relevant to <span class="hlt">climate</span>. These include: changes in subsurface <span class="hlt">ocean</span> temperature and heat content, evidence for regional changes in <span class="hlt">ocean</span> salinity and their link to changes in evaporation and precipitation over the <span class="hlt">oceans</span>, evidence of variability and change of <span class="hlt">ocean</span> current patterns relevant to <span class="hlt">climate</span>, observations of sea level change and predictions over the next century, and biogeochemical changes in the <span class="hlt">ocean</span>, including <span class="hlt">ocean</span> acidification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1020H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1020H"><span>The biological carbon pump in the <span class="hlt">ocean</span>: Reviewing <span class="hlt">model</span> representations and its feedbacks on <span class="hlt">climate</span> perturbations.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hülse, Dominik; Arndt, Sandra; Ridgwell, Andy; Wilson, Jamie</p> <p>2016-04-01</p> <p>The <span class="hlt">ocean</span>-sediment system, as the biggest carbon reservoir in the Earth's carbon cycle, plays a crucial role in regulating atmospheric carbon dioxide concentrations and <span class="hlt">climate</span>. Therefore, it is essential to constrain the importance of marine carbon cycle feedbacks on global warming and <span class="hlt">ocean</span> acidification. Arguably, the most important single component of the <span class="hlt">ocean</span>'s carbon cycle is the so-called "biological carbon pump". It transports carbon that is fixed in the light-flooded surface layer of the <span class="hlt">ocean</span> to the deep <span class="hlt">ocean</span> and the surface sediment, where it is degraded/dissolved or finally buried in the deep sediments. Over the past decade, progress has been made in understanding different factors that control the efficiency of the biological carbon pump and their feedbacks on the global carbon cycle and <span class="hlt">climate</span> (i.e. ballasting = <span class="hlt">ocean</span> acidification feedback; temperature dependant organic matter degradation = global warming feedback; organic matter sulphurisation = anoxia/euxinia feedback). Nevertheless, many uncertainties concerning the interplay of these processes and/or their relative significance remain. In addition, current Earth System <span class="hlt">Models</span> tend to employ empirical and static parameterisations of the biological pump. As these parametric representations are derived from a limited set of present-day observations, their ability to represent carbon cycle feedbacks under changing <span class="hlt">climate</span> conditions is limited. The aim of my research is to combine past carbon cycling information with a spatially resolved global biogeochemical <span class="hlt">model</span> to constrain the functioning of the biological pump and to base its mathematical representation on a more mechanistic approach. Here, I will discuss important aspects that control the efficiency of the <span class="hlt">ocean</span>'s biological carbon pump, review how these processes of first order importance are mathematically represented in existing Earth system <span class="hlt">Models</span> of Intermediate Complexity (EMIC) and distinguish different approaches to approximate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040089728&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040089728&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Methyl bromide: <span class="hlt">ocean</span> sources, <span class="hlt">ocean</span> sinks, and <span class="hlt">climate</span> sensitivity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anbar, A. D.; Yung, Y. L.; Chavez, F. P.</p> <p>1996-01-01</p> <p>The <span class="hlt">oceans</span> play an important role in the geochemical cycle of methyl bromide (CH3Br), the major carrier of O3-destroying bromine to the stratosphere. The quantity of CH3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmosphere is poorly constrained; measurements in seawater and the atmosphere have been used to justify both a large <span class="hlt">oceanic</span> CH3Br flux to the atmosphere and a small net <span class="hlt">ocean</span> sink. Since the consumption reactions are extremely temperature-sensitive, small temperature variations have large effects on the CH3Br concentration in seawater, and therefore on the exchange between the atmosphere and the <span class="hlt">ocean</span>. The net CH3Br flux is also sensitive to variations in the rate of CH3Br production. We have quantified these effects using a simple steady state mass balance <span class="hlt">model</span>. When CH3Br production rates are linearly scaled with seawater chlorophyll content, this <span class="hlt">model</span> reproduces the latitudinal variations in marine CH3Br concentrations observed in the east Pacific <span class="hlt">Ocean</span> by Singh et al. [1983] and by Lobert et al. [1995]. The apparent correlation of CH3Br production with primary production explains the discrepancies between the two observational studies, strengthening recent suggestions that the open <span class="hlt">ocean</span> is a small net sink for atmospheric CH3Br, rather than a large net source. The Southern <span class="hlt">Ocean</span> is implicated as a possible large net source of CH3Br to the atmosphere. Since our <span class="hlt">model</span> indicates that both the direction and magnitude of CH3Br exchange between the atmosphere and <span class="hlt">ocean</span> are extremely sensitive to temperature and marine productivity, and since the rate of CH3Br production in the <span class="hlt">oceans</span> is comparable to the rate at which this compound is introduced to the atmosphere, even small</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11539402','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11539402"><span>Methyl bromide: <span class="hlt">ocean</span> sources, <span class="hlt">ocean</span> sinks, and <span class="hlt">climate</span> sensitivity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anbar, A D; Yung, Y L; Chavez, F P</p> <p>1996-03-01</p> <p>The <span class="hlt">oceans</span> play an important role in the geochemical cycle of methyl bromide (CH3Br), the major carrier of O3-destroying bromine to the stratosphere. The quantity of CH3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmosphere is poorly constrained; measurements in seawater and the atmosphere have been used to justify both a large <span class="hlt">oceanic</span> CH3Br flux to the atmosphere and a small net <span class="hlt">ocean</span> sink. Since the consumption reactions are extremely temperature-sensitive, small temperature variations have large effects on the CH3Br concentration in seawater, and therefore on the exchange between the atmosphere and the <span class="hlt">ocean</span>. The net CH3Br flux is also sensitive to variations in the rate of CH3Br production. We have quantified these effects using a simple steady state mass balance <span class="hlt">model</span>. When CH3Br production rates are linearly scaled with seawater chlorophyll content, this <span class="hlt">model</span> reproduces the latitudinal variations in marine CH3Br concentrations observed in the east Pacific <span class="hlt">Ocean</span> by Singh et al. [1983] and by Lobert et al. [1995]. The apparent correlation of CH3Br production with primary production explains the discrepancies between the two observational studies, strengthening recent suggestions that the open <span class="hlt">ocean</span> is a small net sink for atmospheric CH3Br, rather than a large net source. The Southern <span class="hlt">Ocean</span> is implicated as a possible large net source of CH3Br to the atmosphere. Since our <span class="hlt">model</span> indicates that both the direction and magnitude of CH3Br exchange between the atmosphere and <span class="hlt">ocean</span> are extremely sensitive to temperature and marine productivity, and since the rate of CH3Br production in the <span class="hlt">oceans</span> is comparable to the rate at which this compound is introduced to the atmosphere, even small</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/940218','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/940218"><span>Studies of regional-scale <span class="hlt">climate</span> variability and change. Hidden Markov <span class="hlt">models</span> and coupled <span class="hlt">ocean</span>-atmosphere modes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ghil, M.; Kravtsov, S.; Robertson, A. W.</p> <p>2008-10-14</p> <p>This project was a continuation of previous work under DOE CCPP funding, in which we had developed a twin approach of probabilistic network (PN) <span class="hlt">models</span> (sometimes called dynamic Bayesian networks) and intermediate-complexity coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">models</span> (ICMs) to identify the predictable modes of <span class="hlt">climate</span> variability and to investigate their impacts on the regional scale. We had developed a family of PNs (similar to Hidden Markov <span class="hlt">Models</span>) to simulate historical records of daily rainfall, and used them to downscale GCM seasonal predictions. Using an idealized atmospheric <span class="hlt">model</span>, we had established a novel mechanism through which <span class="hlt">ocean</span>-induced sea-surface temperature (SST) anomalies might influencemore » large-scale atmospheric circulation patterns on interannual and longer time scales; we had found similar patterns in a hybrid coupled <span class="hlt">ocean</span>-atmosphere-sea-ice <span class="hlt">model</span>. The goal of the this continuation project was to build on these ICM results and PN <span class="hlt">model</span> development to address prediction of rainfall and temperature statistics at the local scale, associated with global <span class="hlt">climate</span> variability and change, and to investigate the impact of the latter on coupled <span class="hlt">ocean</span>-atmosphere modes. Our main results from the grant consist of extensive further development of the hidden Markov <span class="hlt">models</span> for rainfall simulation and downscaling together with the development of associated software; new intermediate coupled <span class="hlt">models</span>; a new methodology of inverse <span class="hlt">modeling</span> for linking ICMs with observations and GCM results; and, observational studies of decadal and multi-decadal natural <span class="hlt">climate</span> results, informed by ICM results.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C12B..08T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C12B..08T"><span>The Southern <span class="hlt">Ocean</span>'s role in <span class="hlt">ocean</span> circulation and <span class="hlt">climate</span> transients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, A. F.; Stewart, A.; Hines, S.; Adkins, J. F.</p> <p>2017-12-01</p> <p>The ventilation of deep and intermediate density classes at the surface of the Southern <span class="hlt">Ocean</span> impacts water mass modification and the air-sea exchange of heat and trace gases, which in turn influences the global overturning circulation and Earth's <span class="hlt">climate</span>. Zonal variability occurs along the Antarctic Circumpolar Current and the Antarctic margins related to flow-topography interactions, variations in surface boundary conditions, and exchange with northern basins. Information about these zonal variations, and their impact on mass and tracer transport, are suppressed when the overturning is depicted as a two-dimensional (depth-latitude) streamfunction. Here we present an idealized, multi-basin, time-dependent circulation <span class="hlt">model</span> that applies residual circulation theory in the Southern <span class="hlt">Ocean</span> and allows for zonal water mass transfer between different <span class="hlt">ocean</span> basins. This <span class="hlt">model</span> efficiently determines the temporal evolution of the <span class="hlt">ocean</span>'s stratification, ventilation and overturning strength in response to perturbations in the external forcing. With this <span class="hlt">model</span> we explore the dynamics that lead to transitions in the circulation structure between multiple, isolated cells and a three-dimensional, "figure-of-eight," circulation in which traditional upper and lower cells are interleaved. The transient <span class="hlt">model</span> is also used to support a mechanistic explanation of the hemispheric asymmetry and phase lag associated with Dansgaard-Oeschger (DO) events during the last glacial period. In particular, the 200 year lag in southern hemisphere temperatures, following a perturbation in North Atlantic deep water formation, depends critically on the migration of Southern <span class="hlt">Ocean</span> isopycnal outcropping in response to low-latitude stratification changes. Our results provide a self-consistent dynamical framework to explain various <span class="hlt">ocean</span> overturning transitions that have occurred over the Earth's last 100,000 years, and motivate an exploration of these mechanisms in more sophisticated <span class="hlt">climate</span> <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP31E..05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP31E..05T"><span>Intensified Indian <span class="hlt">Ocean</span> <span class="hlt">climate</span> variability during the Last Glacial Maximum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thirumalai, K.; DiNezro, P.; Tierney, J. E.; Puy, M.; Mohtadi, M.</p> <p>2017-12-01</p> <p><span class="hlt">Climate</span> <span class="hlt">models</span> project increased year-to-year <span class="hlt">climate</span> variability in the equatorial Indian <span class="hlt">Ocean</span> in response to greenhouse gas warming. This response has been attributed to changes in the mean <span class="hlt">climate</span> of the Indian <span class="hlt">Ocean</span> associated with the zonal sea-surface temperature (SST) gradient. According to these studies, air-sea coupling is enhanced due to a stronger SST gradient driving anomalous easterlies that shoal the thermocline in the eastern Indian <span class="hlt">Ocean</span>. We propose that this relationship between the variability and the zonal SST gradient is consistent across different mean <span class="hlt">climate</span> states. We test this hypothesis using simulations of past and future <span class="hlt">climate</span> performed with the Community Earth System <span class="hlt">Model</span> Version 1 (CESM1). We constrain the realism of the <span class="hlt">model</span> for the Last Glacial Maximum (LGM) where CESM1 simulates a mean <span class="hlt">climate</span> consistent with a stronger SST gradient, agreeing with proxy reconstructions. CESM1 also simulates a pronounced increase in seasonal and interannual variability. We develop new estimates of <span class="hlt">climate</span> variability on these timescales during the LGM using δ18O analysis of individual foraminifera (IFA). IFA data generated from four different cores located in the eastern Indian <span class="hlt">Ocean</span> indicate a marked increase in δ18O-variance during the LGM as compared to the late Holocene. Such a significant increase in the IFA-δ18O variance strongly supports the <span class="hlt">modeling</span> simulations. This agreement further supports the dynamics linking year-to-year variability and an altered SST gradient, increasing our confidence in <span class="hlt">model</span> projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23112174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23112174"><span>Indian <span class="hlt">Ocean</span> warming modulates Pacific <span class="hlt">climate</span> change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Jing-Jia; Sasaki, Wataru; Masumoto, Yukio</p> <p>2012-11-13</p> <p>It has been widely believed that the tropical Pacific trade winds weakened in the last century and would further decrease under a warmer <span class="hlt">climate</span> in the 21st century. Recent high-quality observations, however, suggest that the tropical Pacific winds have actually strengthened in the past two decades. Precise causes of the recent Pacific <span class="hlt">climate</span> shift are uncertain. Here we explore how the enhanced tropical Indian <span class="hlt">Ocean</span> warming in recent decades favors stronger trade winds in the western Pacific via the atmosphere and hence is likely to have contributed to the La Niña-like state (with enhanced east-west Walker circulation) through the Pacific <span class="hlt">ocean</span>-atmosphere interactions. Further analysis, based on 163 <span class="hlt">climate</span> <span class="hlt">model</span> simulations with centennial historical and projected external radiative forcing, suggests that the Indian <span class="hlt">Ocean</span> warming relative to the Pacific's could play an important role in modulating the Pacific <span class="hlt">climate</span> changes in the 20th and 21st centuries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ChJOL..35...23Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ChJOL..35...23Y"><span><span class="hlt">Climate</span> variability and predictability associated with the Indo-Pacific <span class="hlt">Oceanic</span> Channel Dynamics in the CCSM4 Coupled System <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Dongliang; Xu, Peng; Xu, Tengfei</p> <p>2017-01-01</p> <p>An experiment using the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CCSM4), a participant of the Coupled <span class="hlt">Model</span> Intercomparison Project phase-5 (CMIP5), is analyzed to assess the skills of this <span class="hlt">model</span> in simulating and predicting the <span class="hlt">climate</span> variabilities associated with the <span class="hlt">oceanic</span> channel dynamics across the Indo-Pacific <span class="hlt">Oceans</span>. The results of these analyses suggest that the <span class="hlt">model</span> is able to reproduce the observed lag correlation between the <span class="hlt">oceanic</span> anomalies in the southeastern tropical Indian <span class="hlt">Ocean</span> and those in the cold tongue in the eastern equatorial Pacific <span class="hlt">Ocean</span> at a time lag of 1 year. This success may be largely attributed to the successful simulation of the interannual variations of the Indonesian Throughflow, which carries the anomalies of the Indian <span class="hlt">Ocean</span> Dipole (IOD) into the western equatorial Pacific <span class="hlt">Ocean</span> to produce subsurface temperature anomalies, which in turn propagate to the eastern equatorial Pacific to generate ENSO. This connection is termed the "<span class="hlt">oceanic</span> channel dynamics" and is shown to be consistent with the observational analyses. However, the <span class="hlt">model</span> simulates a weaker connection between the IOD and the interannual variability of the Indonesian Throughflow transport than found in the observations. In addition, the <span class="hlt">model</span> overestimates the westerly wind anomalies in the western-central equatorial Pacific in the year following the IOD, which forces unrealistic upwelling Rossby waves in the western equatorial Pacific and downwelling Kelvin waves in the east. This assessment suggests that the CCSM4 coupled <span class="hlt">climate</span> system has underestimated the <span class="hlt">oceanic</span> channel dynamics and overestimated the atmospheric bridge processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Sci...350..766L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Sci...350..766L"><span>The deep <span class="hlt">ocean</span> under <span class="hlt">climate</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levin, Lisa A.; Le Bris, Nadine</p> <p>2015-11-01</p> <p>The deep <span class="hlt">ocean</span> absorbs vast amounts of heat and carbon dioxide, providing a critical buffer to <span class="hlt">climate</span> change but exposing vulnerable ecosystems to combined stresses of warming, <span class="hlt">ocean</span> acidification, deoxygenation, and altered food inputs. Resulting changes may threaten biodiversity and compromise key <span class="hlt">ocean</span> services that maintain a healthy planet and human livelihoods. There exist large gaps in understanding of the physical and ecological feedbacks that will occur. Explicit recognition of deep-<span class="hlt">ocean</span> <span class="hlt">climate</span> mitigation and inclusion in adaptation planning by the United Nations Framework Convention on <span class="hlt">Climate</span> Change (UNFCCC) could help to expand deep-<span class="hlt">ocean</span> research and observation and to protect the integrity and functions of deep-<span class="hlt">ocean</span> ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B11B0482C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B11B0482C"><span>The Impact of the <span class="hlt">Ocean</span> Sulfur Cycle on <span class="hlt">Climate</span> using the Community Earth System <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cameron-Smith, P. J.; Elliott, S. M.; Bergmann, D. J.; Branstetter, M. L.; Chuang, C.; Erickson, D. J.; Jacob, R. L.; Maltrud, M. E.; Mirin, A. A.</p> <p>2011-12-01</p> <p>Chemical cycling between the various Earth system components (atmosphere, biosphere, land, <span class="hlt">ocean</span>, and sea-ice) can cause positive and negative feedbacks on the <span class="hlt">climate</span> system. The long-standing CLAW/GAIA hypothesis proposed that global warming might stimulate increased production of dimethyl sulfide (DMS) by plankton in the <span class="hlt">ocean</span>, which would then provide a negative <span class="hlt">climate</span> feedback through atmospheric oxidation of the DMS to sulfate aerosols that reflect sunlight directly, and indirectly by affecting clouds. Our state-of-the-art earth system <span class="hlt">model</span> (CESM with an <span class="hlt">ocean</span> sulfur cycle and atmospheric chemistry) shows increased production of DMS over the 20th century by plankton, particularly in the Southern <span class="hlt">Ocean</span> and Equatorial Pacific, which leads to modest cooling from direct reflection of sunlight in those regions. This suggests the possibility of local <span class="hlt">climate</span> change mitigation by the plankton species that produce DMS. Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910050237&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910050237&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Increased <span class="hlt">ocean</span> heat transports and warmer <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rind, D.; Chandler, M.</p> <p>1991-01-01</p> <p>The impact of an increased <span class="hlt">ocean</span> heat transport on <span class="hlt">climate</span> is investigated in the framework of the GISS GMC <span class="hlt">model</span> described by Hansen et al. (1983), using two scenarios: one starting from warmer polar temperatures/no sea ice and the other from the current <span class="hlt">ocean</span> conditions. A 20-percent increase in cross-equatorial heat transport was sufficient to melt all sea ice; it resulted in a <span class="hlt">climate</span> that was 2 C warmer for the global average, with values some 20-deg warmer at high altitudes and 1-deg warmer near the equator. It is suggested that the hydrological and dynamical changes associated with this different <span class="hlt">climate</span> regime may be self-sustaining and, as such, would account for the high-latitude warmth of <span class="hlt">climates</span> in the Mesozoic and Tertiary periods and the decadenal-scale <span class="hlt">climate</span> fluctuations during the Holocene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26564845','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26564845"><span>The deep <span class="hlt">ocean</span> under <span class="hlt">climate</span> change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Levin, Lisa A; Le Bris, Nadine</p> <p>2015-11-13</p> <p>The deep <span class="hlt">ocean</span> absorbs vast amounts of heat and carbon dioxide, providing a critical buffer to <span class="hlt">climate</span> change but exposing vulnerable ecosystems to combined stresses of warming, <span class="hlt">ocean</span> acidification, deoxygenation, and altered food inputs. Resulting changes may threaten biodiversity and compromise key <span class="hlt">ocean</span> services that maintain a healthy planet and human livelihoods. There exist large gaps in understanding of the physical and ecological feedbacks that will occur. Explicit recognition of deep-<span class="hlt">ocean</span> <span class="hlt">climate</span> mitigation and inclusion in adaptation planning by the United Nations Framework Convention on <span class="hlt">Climate</span> Change (UNFCCC) could help to expand deep-<span class="hlt">ocean</span> research and observation and to protect the integrity and functions of deep-<span class="hlt">ocean</span> ecosystems. Copyright © 2015, American Association for the Advancement of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C12B..07R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C12B..07R"><span><span class="hlt">Climate</span> in the absence of <span class="hlt">ocean</span> heat transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rose, B. E. J.</p> <p>2017-12-01</p> <p>The energy transported by the <span class="hlt">oceans</span> to mid- and high latitudes is small compared to the atmosphere, yet exerts an outsized influence on <span class="hlt">climate</span>. A key reason is the strong interaction between <span class="hlt">ocean</span> heat transport (OHT) and sea ice extent. I quantify the absolute <span class="hlt">climatic</span> impact of OHT using the state-of-the-art CESM simulations by comparing a realistic control <span class="hlt">climate</span> against a slab <span class="hlt">ocean</span> simulation in which OHT is disabled. The absence of OHT leads to a massive expansion of sea ice into the subtropics in both hemispheres, and a 24 K global cooling. Analysis of the transient simulation after setting the OHT to zero reveals a global cooling process fueled by a runaway sea ice albedo feedback. This process is eventually self-limiting in the cold <span class="hlt">climate</span> due to a combination of subtropical cloud feedbacks and surface wind effects that are both connected to a massive spin-up of the atmospheric Hadley circulation. A parameter sensitivity study shows that the simulated <span class="hlt">climate</span> is far more sensitive to small changes in ice surface albedo in the absence of OHT. I conclude that the <span class="hlt">oceans</span> are responsible for an enormous global warming by mitigating an otherwise very potent sea ice albedo feedback, but that the magnitude of this effect is rather uncertain. These simulations provide a graphic illustration of how the intimate coupling between sea ice and <span class="hlt">ocean</span> circulation governs the present-day <span class="hlt">climate</span>, and by extension, highlight the importance of <span class="hlt">modeling</span> <span class="hlt">ocean</span> - sea ice interaction with high fidelity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.noaa.gov/climate','SCIGOVWS'); return false;" href="http://www.noaa.gov/climate"><span><span class="hlt">Climate</span> | National <span class="hlt">Oceanic</span> and Atmospheric Administration</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>to help people understand and prepare for <em><span class="hlt">climate</span></em> variability and <em>change</em>. <em><span class="hlt">Climate</span></em>. NOAA From to help people understand and prepare for <em><span class="hlt">climate</span></em> variability and <em>change</em>. LATEST FEATURES // <span class="hlt">Ocean</span> Jump to Content Enter Search Terms Weather <em><span class="hlt">Climate</span></em> <span class="hlt">Oceans</span> & Coasts Fisheries Satellites</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P53E2669S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P53E2669S"><span>Tide, <span class="hlt">Ocean</span> and <span class="hlt">Climate</span> on Exoplanets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Si, Y.; Yang, J.</p> <p>2017-12-01</p> <p>On Earth, tide is a main part of the driving force for the deep <span class="hlt">ocean</span> overturning circulation. For habitable planets around low-mass stars, the tidal force is expected to be much stronger than that on Earth, due to the fact that the habitable zone is very close to the host stars and that tide force is inversely proportional to the orbital distance cubed. The deep <span class="hlt">ocean</span> overturning circulation on this type of planets is therefore expected to be much stronger than that on Earth, if all else being equal. We test this hypothesis using a fully coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span>, the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> version 3 (CCSM3). Our results show that the intensity of <span class="hlt">oceanic</span> meridional overturning circulation (MOC) is approximately proportional to κ1/3, where κ is the mixing coefficient across density interfaces and it is mainly determined by the strength of the tidal force. As a result of the enhanced MOC, more heat is transported to dark regions and sea ice melts completely there, and meanwhile more heat is mixed from the surface to the deep <span class="hlt">ocean</span> and thereby the entire <span class="hlt">ocean</span> becomes much warmer (Fig. 1). A positive cloud feedback further warms the global <span class="hlt">ocean</span> and atmosphere. These results imply that one planet with a stronger tidal force will likely enter a globally ice-covered snowball state at a lower stellar flux and enter a moist greenhouse or runaway greenhouse state at also a lower stellar flux, meaning that the tidal force acts to push the habitable zone outward. This study significantly improves our understanding of the possible coupling between planetary orbit, <span class="hlt">ocean</span>, <span class="hlt">climate</span>, and habitability on exoplanets.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51L..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51L..02D"><span>Role of the North Atlantic <span class="hlt">Ocean</span> in Low Frequency <span class="hlt">Climate</span> Variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Danabasoglu, G.; Yeager, S. G.; Kim, W. M.; Castruccio, F. S.</p> <p>2017-12-01</p> <p>The Atlantic <span class="hlt">Ocean</span> is a unique basin with its extensive, North - South overturning circulation, referred to as the Atlantic meridional overturning circulation (AMOC). AMOC is thought to represent the dynamical memory of the <span class="hlt">climate</span> system, playing an important role in decadal and longer time scale <span class="hlt">climate</span> variability as well as prediction of the earth's future <span class="hlt">climate</span> on these time scales via its large heat and salt transports. This <span class="hlt">oceanic</span> memory is communicated to the atmosphere primarily through the influence of persistent sea surface temperature (SST) variations. Indeed, many <span class="hlt">modeling</span> studies suggest that <span class="hlt">ocean</span> circulation, i.e., AMOC, is largely responsible for the creation of coherent SST variability in the North Atlantic, referred to as Atlantic Multidecadal Variability (AMV). AMV has been linked to many (multi)decadal <span class="hlt">climate</span> variations in, e.g., Sahel and Brazilian rainfall, Atlantic hurricane activity, and Arctic sea-ice extent. In the absence of long, continuous observations, much of the evidence for the <span class="hlt">ocean</span>'s role in (multi)decadal variability comes from <span class="hlt">model</span> simulations. Although <span class="hlt">models</span> tend to agree on the role of the North Atlantic Oscillation in creating the density anomalies that proceed the changes in <span class="hlt">ocean</span> circulation, <span class="hlt">model</span> fidelity in representing variability characteristics, mechanisms, and air-sea interactions remains a serious concern. In particular, there is increasing evidence that <span class="hlt">models</span> significantly underestimate low frequency variability in the North Atlantic compared to available observations. Such <span class="hlt">model</span> deficiencies can amplify the relative influence of external or stochastic atmospheric forcing in generating (multi)decadal variability, i.e., AMV, at the expense of <span class="hlt">ocean</span> dynamics. Here, a succinct overview of the current understanding of the (North) Atlantic <span class="hlt">Ocean</span>'s role on the regional and global <span class="hlt">climate</span>, including some outstanding questions, will be presented. In addition, a few examples of the <span class="hlt">climate</span> impacts of the AMV via</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JCli...18.1449C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JCli...18.1449C"><span>Indian <span class="hlt">Ocean</span> Dipolelike Variability in the CSIRO Mark 3 Coupled <span class="hlt">Climate</span> <span class="hlt">Model</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Wenju; Hendon, Harry H.; Meyers, Gary</p> <p>2005-05-01</p> <p>Coupled <span class="hlt">ocean</span>-atmosphere variability in the tropical Indian <span class="hlt">Ocean</span> is explored with a multicentury integration of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Mark 3 <span class="hlt">climate</span> <span class="hlt">model</span>, which runs without flux adjustment. Despite the presence of some common deficiencies in this type of coupled <span class="hlt">model</span>, zonal dipolelike variability is produced. During July through November, the dominant mode of variability of sea surface temperature resembles the observed zonal dipole and has out-of-phase rainfall variations across the Indian <span class="hlt">Ocean</span> basin, which are as large as those associated with the <span class="hlt">model</span> El Niño-Southern Oscillation (ENSO). In the positive dipole phase, cold SST anomaly and suppressed rainfall south of the equator on the Sumatra-Java coast drives an anticyclonic circulation anomaly that is consistent with the steady response (Gill <span class="hlt">model</span>) to a heat sink displaced south of the equator. The northwest-southeast tilting Sumatra-Java coast results in cold sea surface temperature (SST) centered south of the equator, which forces anticylonic winds that are southeasterly along the coast, which thus produces local upwelling, cool SSTs, and promotes more anticylonic winds; on the equator, the easterlies raise the thermocline to the east via upwelling Kelvin waves and deepen the off-equatorial thermocline to the west via off-equatorial downwelling Rossby waves. The <span class="hlt">model</span> dipole mode exhibits little contemporaneous relationship with the <span class="hlt">model</span> ENSO; however, this does not imply that it is independent of ENSO. The <span class="hlt">model</span> dipole often (but not always) develops in the year following El Niño. It is triggered by an unrealistic transmission of the <span class="hlt">model</span>'s ENSO discharge phase through the Indonesian passages. In the <span class="hlt">model</span>, the ENSO discharge Rossby waves arrive at the Sumatra-Java coast some 6 to 9 months after an El Niño peaks, causing the majority of <span class="hlt">model</span> dipole events to peak in the year after an ENSO warm event. In the observed ENSO discharge, Rossby waves</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMED11D..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMED11D..03S"><span>Global <span class="hlt">Climate</span> Change and <span class="hlt">Ocean</span> Education</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spitzer, W.; Anderson, J.</p> <p>2011-12-01</p> <p> the Earth's <span class="hlt">climate</span> system. The problem is not simply that the public lacks information. In fact, the problem is often that there is too much information available with much of it complicated and even contradictory. The news media, both print and electronic, tend to exacerbate this by aiming for "balance" even when there is an overwhelming scientific or policy consensus. An additional problem is "reinforcement bias," which tends to lead people to focus on information that supports what they already believe or think they know. Instead, we need an approach that facilitates "meaning-making." A "framing" approach to communication (Frameworks Institute, 2010) supports meaning-making by appealing to strongly held values, providing metaphoric language and <span class="hlt">models</span>, and illustrating specific applications to real world problems. This approach translates complex science in a way that allows people to examine evidence, make well-informed decisions, and embrace science-based solutions. However, interpreters need specialized training, resources, up-to-date information, and ongoing support to help understand a complex topic such as <span class="hlt">climate</span> change, its connections to the <span class="hlt">ocean</span>, and how to relate it to the live animals, habitats and exhibits they interpret.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMED23B0825W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMED23B0825W"><span>Explor<span class="hlt">Ocean</span> H2O SOS: Help Heal the <span class="hlt">Ocean</span>-Student Operated Solutions: Operation <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weiss, N.; Wood, J. H.</p> <p>2016-12-01</p> <p>The Explor<span class="hlt">Ocean</span> H2O SOS: Help Heal the Ocean—Student Operated Solutions: Operation <span class="hlt">Climate</span> Change, teaches middle and high school students about <span class="hlt">ocean</span> threats related to <span class="hlt">climate</span> change through hands-on activities and learning experiences in the field. During each session (in-class or after-school as a club), students build an understanding about how <span class="hlt">climate</span> change impacts our <span class="hlt">oceans</span> using resources provided by Explor<span class="hlt">Ocean</span> (hands-on activities, presentations, multi-media). Through a student leadership <span class="hlt">model</span>, students present lessons to each other, interweaving a deep learning of science, 21st century technology, communication skills, and leadership. After participating in learning experiences and activities related to 6 key <span class="hlt">climate</span> change concepts: 1) Introduction to <span class="hlt">climate</span> change, 2) Increased sea temperatures, 3) <span class="hlt">Ocean</span> acidification, 4) Sea level rise, 5) Feedback mechanisms, and 6) Innovative solutions. H2O SOS- Operation <span class="hlt">Climate</span> change participants select one focus issue and use it to design a multi-pronged campaign to increase awareness about this issue in their local community. The campaign includes social media, an interactive activity, and a visual component. All participating clubs that meet participation and action goals earn a field trip to Explor<span class="hlt">Ocean</span> where they dive deeper into their selected issue through hands-on activities, real-world investigations, and interviews or presentations with experts. In addition to self-selected opportunities to showcase their focus issue, teams will participate in one of several key events identified by Explor<span class="hlt">Ocean</span>, including Explor<span class="hlt">Ocean</span>'s annual World <span class="hlt">Oceans</span> Day Expo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5481837','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5481837"><span>Skillful prediction of northern <span class="hlt">climate</span> provided by the <span class="hlt">ocean</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Årthun, Marius; Eldevik, Tor; Viste, Ellen; Drange, Helge; Furevik, Tore; Johnson, Helen L.; Keenlyside, Noel S.</p> <p>2017-01-01</p> <p>It is commonly understood that a potential for skillful <span class="hlt">climate</span> prediction resides in the <span class="hlt">ocean</span>. It nevertheless remains unresolved to what extent variable <span class="hlt">ocean</span> heat is imprinted on the atmosphere to realize its predictive potential over land. Here we assess from observations whether anomalous heat in the Gulf Stream's northern extension provides predictability of northwestern European and Arctic <span class="hlt">climate</span>. We show that variations in <span class="hlt">ocean</span> temperature in the high latitude North Atlantic and Nordic Seas are reflected in the <span class="hlt">climate</span> of northwestern Europe and in winter Arctic sea ice extent. Statistical regression <span class="hlt">models</span> show that a significant part of northern <span class="hlt">climate</span> variability thus can be skillfully predicted up to a decade in advance based on the state of the <span class="hlt">ocean</span>. Particularly, we predict that Norwegian air temperature will decrease over the coming years, although staying above the long-term (1981–2010) average. Winter Arctic sea ice extent will remain low but with a general increase towards 2020. PMID:28631732</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatCo...815875A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatCo...815875A"><span>Skillful prediction of northern <span class="hlt">climate</span> provided by the <span class="hlt">ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Årthun, Marius; Eldevik, Tor; Viste, Ellen; Drange, Helge; Furevik, Tore; Johnson, Helen L.; Keenlyside, Noel S.</p> <p>2017-06-01</p> <p>It is commonly understood that a potential for skillful <span class="hlt">climate</span> prediction resides in the <span class="hlt">ocean</span>. It nevertheless remains unresolved to what extent variable <span class="hlt">ocean</span> heat is imprinted on the atmosphere to realize its predictive potential over land. Here we assess from observations whether anomalous heat in the Gulf Stream's northern extension provides predictability of northwestern European and Arctic <span class="hlt">climate</span>. We show that variations in <span class="hlt">ocean</span> temperature in the high latitude North Atlantic and Nordic Seas are reflected in the <span class="hlt">climate</span> of northwestern Europe and in winter Arctic sea ice extent. Statistical regression <span class="hlt">models</span> show that a significant part of northern <span class="hlt">climate</span> variability thus can be skillfully predicted up to a decade in advance based on the state of the <span class="hlt">ocean</span>. Particularly, we predict that Norwegian air temperature will decrease over the coming years, although staying above the long-term (1981-2010) average. Winter Arctic sea ice extent will remain low but with a general increase towards 2020.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1029980-climate-sensitivity-community-climate-system-model-version','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1029980-climate-sensitivity-community-climate-system-model-version"><span><span class="hlt">Climate</span> Sensitivity of the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span>, Version 4</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Bitz, Cecilia M.; Shell, K. M.; Gent, P. R.; ...</p> <p>2012-05-01</p> <p>Equilibrium <span class="hlt">climate</span> sensitivity of the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> Version 4 (CCSM4) is 3.20°C for 1° horizontal resolution in each component. This is about a half degree Celsius higher than in the previous version (CCSM3). The transient <span class="hlt">climate</span> sensitivity of CCSM4 at 1° resolution is 1.72°C, which is about 0.2°C higher than in CCSM3. These higher <span class="hlt">climate</span> sensitivities in CCSM4 cannot be explained by the change to a preindustrial baseline <span class="hlt">climate</span>. We use the radiative kernel technique to show that from CCSM3 to CCSM4, the global mean lapse-rate feedback declines in magnitude, and the shortwave cloud feedback increases. These twomore » warming effects are partially canceled by cooling due to slight decreases in the global mean water-vapor feedback and longwave cloud feedback from CCSM3 to CCSM4. A new formulation of the mixed-layer, slab <span class="hlt">ocean</span> <span class="hlt">model</span> in CCSM4 attempts to reproduce the SST and sea ice climatology from an integration with a full-depth <span class="hlt">ocean</span>, and it is integrated with a dynamic sea ice <span class="hlt">model</span>. These new features allow an isolation of the influence of <span class="hlt">ocean</span> dynamical changes on the <span class="hlt">climate</span> response when comparing integrations with the slab <span class="hlt">ocean</span> and full-depth <span class="hlt">ocean</span>. The transient <span class="hlt">climate</span> response of the full-depth <span class="hlt">ocean</span> version is 0.54 of the equilibrium <span class="hlt">climate</span> sensitivity when estimated with the new slab <span class="hlt">ocean</span> <span class="hlt">model</span> version for both CCSM3 and CCSM4. We argue the ratio is the same in both versions because they have about the same zonal mean pattern of change in <span class="hlt">ocean</span> surface heat flux, which broadly resembles the zonal mean pattern of net feedback strength.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ERL.....9f4005C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ERL.....9f4005C"><span>Sensitivity of <span class="hlt">ocean</span> acidification and oxygen to the uncertainty in <span class="hlt">climate</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Long; Wang, Shuangjing; Zheng, Meidi; Zhang, Han</p> <p>2014-05-01</p> <p>Due to increasing atmospheric CO2 concentrations and associated <span class="hlt">climate</span> change, the global <span class="hlt">ocean</span> is undergoing substantial physical and biogeochemical changes. Among these, changes in <span class="hlt">ocean</span> oxygen and carbonate chemistry have great implication for marine biota. There is considerable uncertainty in the projections of future <span class="hlt">climate</span> change, and it is unclear how the uncertainty in <span class="hlt">climate</span> change would also affect the projection of oxygen and carbonate chemistry. To investigate this issue, we use an Earth system <span class="hlt">model</span> of intermediate complexity to perform a set of simulations, including that which involves no radiative effect of atmospheric CO2 and those which involve CO2-induced <span class="hlt">climate</span> change with <span class="hlt">climate</span> sensitivity varying from 0.5 °C to 4.5 °C. Atmospheric CO2 concentration is prescribed to follow RCP 8.5 pathway and its extensions. <span class="hlt">Climate</span> change affects carbonate chemistry and oxygen mainly through its impact on <span class="hlt">ocean</span> temperature, <span class="hlt">ocean</span> ventilation, and concentration of dissolved inorganic carbon and alkalinity. It is found that <span class="hlt">climate</span> change mitigates the decrease of carbonate ions at the <span class="hlt">ocean</span> surface but has negligible effect on surface <span class="hlt">ocean</span> pH. Averaged over the whole <span class="hlt">ocean</span>, <span class="hlt">climate</span> change acts to decrease oxygen concentration but mitigates the CO2-induced reduction of carbonate ion and pH. In our simulations, by year 2500, every degree increase of <span class="hlt">climate</span> sensitivity warms the <span class="hlt">ocean</span> by 0.8 °C and reduces <span class="hlt">ocean</span>-mean dissolved oxygen concentration by 5.0%. Meanwhile, every degree increase of <span class="hlt">climate</span> sensitivity buffers CO2-induced reduction in <span class="hlt">ocean</span>-mean carbonate ion concentration and pH by 3.4% and 0.02 units, respectively. Our study demonstrates different sensitivities of <span class="hlt">ocean</span> temperature, carbonate chemistry, and oxygen, in terms of both the sign and magnitude to the amount of <span class="hlt">climate</span> change, which have great implications for understanding the response of <span class="hlt">ocean</span> biota to <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2383S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2383S"><span>Atmosphere surface storm track response to resolved <span class="hlt">ocean</span> mesoscale in two sets of global <span class="hlt">climate</span> <span class="hlt">model</span> experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Small, R. Justin; Msadek, Rym; Kwon, Young-Oh; Booth, James F.; Zarzycki, Colin</p> <p>2018-05-01</p> <p>It has been hypothesized that the <span class="hlt">ocean</span> mesoscale (particularly <span class="hlt">ocean</span> fronts) can affect the strength and location of the overlying extratropical atmospheric storm track. In this paper, we examine whether resolving <span class="hlt">ocean</span> fronts in global <span class="hlt">climate</span> <span class="hlt">models</span> indeed leads to significant improvement in the simulated storm track, defined using low level meridional wind. Two main sets of experiments are used: (i) global <span class="hlt">climate</span> <span class="hlt">model</span> Community Earth System <span class="hlt">Model</span> version 1 with non-eddy-resolving standard resolution or with <span class="hlt">ocean</span> eddy-resolving resolution, and (ii) the same but with the GFDL <span class="hlt">Climate</span> <span class="hlt">Model</span> version 2. In case (i), it is found that higher <span class="hlt">ocean</span> resolution leads to a reduction of a very warm sea surface temperature (SST) bias at the east coasts of the U.S. and Japan seen in standard resolution <span class="hlt">models</span>. This in turn leads to a reduction of storm track strength near the coastlines, by up to 20%, and a better location of the storm track maxima, over the western boundary currents as observed. In case (ii), the change in absolute SST bias in these regions is less notable, and there are modest (10% or less) increases in surface storm track, and smaller changes in the free troposphere. In contrast, in the southern Indian <span class="hlt">Ocean</span>, case (ii) shows most sensitivity to <span class="hlt">ocean</span> resolution, and this coincides with a larger change in mean SST as <span class="hlt">ocean</span> resolution is changed. Where the <span class="hlt">ocean</span> resolution does make a difference, it consistently brings the storm track closer in appearance to that seen in ERA-Interim Reanalysis data. Overall, for the range of <span class="hlt">ocean</span> <span class="hlt">model</span> resolutions used here (1° versus 0.1°) we find that the differences in SST gradient have a small effect on the storm track strength whilst changes in absolute SST between experiments can have a larger effect. The latter affects the land-sea contrast, air-sea stability, surface latent heat flux, and the boundary layer baroclinicity in such a way as to reduce storm track activity adjacent to the western boundary in the N</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.7168M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.7168M"><span>Interbasin effects of the Indian <span class="hlt">Ocean</span> on Pacific decadal <span class="hlt">climate</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mochizuki, Takashi; Kimoto, Masahide; Watanabe, Masahiro; Chikamoto, Yoshimitsu; Ishii, Masayoshi</p> <p>2016-07-01</p> <p>We demonstrate the significant impact of the Indian <span class="hlt">Ocean</span> on the Pacific <span class="hlt">climate</span> on decadal timescales by comparing two sets of data assimilation experiments (pacemaker experiments) conducted over recent decades. For the Indian <span class="hlt">Ocean</span> of an atmosphere-<span class="hlt">ocean</span> coupled global <span class="hlt">climate</span> <span class="hlt">model</span>, we assimilate <span class="hlt">ocean</span> temperature and salinity anomalies defined as deviations from climatology or as anomalies with the area-averaged changes for the Indian <span class="hlt">Ocean</span> subtracted. When decadal sea surface temperature (SST) trends are observed to be strong over the Indian <span class="hlt">Ocean</span>, the equatorial thermocline uniformly deepens, and the <span class="hlt">model</span> simulates the eastward tendencies of surface wind aloft. Surface winds strongly converge around the maritime continent, and the associated strengthening of the Walker circulation suppresses an increasing trend in the equatorial Pacific SST through <span class="hlt">ocean</span> thermocline shoaling, similar to common changes associated with seasonal Indian <span class="hlt">Ocean</span> warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920015950','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920015950"><span><span class="hlt">Climate</span> and atmospheric <span class="hlt">modeling</span> studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>The <span class="hlt">climate</span> and atmosphere <span class="hlt">modeling</span> research programs have concentrated on the development of appropriate atmospheric and upper <span class="hlt">ocean</span> <span class="hlt">models</span>, and preliminary applications of these <span class="hlt">models</span>. Principal <span class="hlt">models</span> are a one-dimensional radiative-convective <span class="hlt">model</span>, a three-dimensional global <span class="hlt">model</span>, and an upper <span class="hlt">ocean</span> <span class="hlt">model</span>. Principal applications were the study of the impact of CO2, aerosols, and the solar 'constant' on <span class="hlt">climate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790015713','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790015713"><span>Atmospheric and oceanographic research review, 1978. [global weather, <span class="hlt">ocean</span>/air interactions, and <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1978-01-01</p> <p>Research activities related to global weather, <span class="hlt">ocean</span>/air interactions, and <span class="hlt">climate</span> are reported. The global weather research is aimed at improving the assimilation of satellite-derived data in weather forecast <span class="hlt">models</span>, developing analysis/forecast <span class="hlt">models</span> that can more fully utilize satellite data, and developing new measures of forecast skill to properly assess the impact of satellite data on weather forecasting. The oceanographic research goal is to understand and <span class="hlt">model</span> the processes that determine the general circulation of the <span class="hlt">oceans</span>, focusing on those processes that affect sea surface temperature and <span class="hlt">oceanic</span> heat storage, which are the oceanographic variables with the greatest influence on <span class="hlt">climate</span>. The <span class="hlt">climate</span> research objective is to support the development and effective utilization of space-acquired data systems in <span class="hlt">climate</span> forecast <span class="hlt">models</span> and to conduct sensitivity studies to determine the affect of lower boundary conditions on <span class="hlt">climate</span> and predictability studies to determine which global <span class="hlt">climate</span> features can be <span class="hlt">modeled</span> either deterministically or statistically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMED31F3487H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMED31F3487H"><span>Assessing <span class="hlt">ocean</span> vertical mixing schemes for the study of <span class="hlt">climate</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howard, A. M.; Lindo, F.; Fells, J.; Tulsee, V.; Cheng, Y.; Canuto, V.</p> <p>2014-12-01</p> <p><span class="hlt">Climate</span> change is a burning issue of our time. It is critical to know the consequences of choosing "business as usual" vs. mitigating our emissions for impacts e.g. ecosystem disruption, sea-level rise, floods and droughts. To make predictions we must <span class="hlt">model</span> realistically each component of the <span class="hlt">climate</span> system. The <span class="hlt">ocean</span> must be <span class="hlt">modeled</span> carefully as it plays a critical role, including transporting heat and storing heat and dissolved carbon dioxide. <span class="hlt">Modeling</span> the <span class="hlt">ocean</span> realistically in turn requires physically based parameterizations of key processes in it that cannot be explicitly represented in a global <span class="hlt">climate</span> <span class="hlt">model</span>. One such process is vertical mixing. The turbulence group at NASA-GISS has developed a comprehensive new vertical mixing scheme (GISSVM) based on turbulence theory, including surface convection and wind shear, interior waves and double-diffusion, and bottom tides. The GISSVM is tested in stand-alone <span class="hlt">ocean</span> simulations before being used in coupled <span class="hlt">climate</span> <span class="hlt">models</span>. It is also being upgraded to more faithfully represent the physical processes. To help assess mixing schemes, students use data from NASA-GISS to create visualizations and calculate statistics including mean bias and rms differences and correlations of fields. These are created and programmed with MATLAB. Results with the commonly used KPP mixing scheme and the present GISSVM and candidate improved variants of GISSVM will be compared between stand-alone <span class="hlt">ocean</span> <span class="hlt">models</span> and coupled <span class="hlt">models</span> and observations. This project introduces students to <span class="hlt">modeling</span> of a complex system, an important theme in contemporary science and helps them gain a better appreciation of <span class="hlt">climate</span> science and a new perspective on it. They also gain familiarity with MATLAB, a widely used tool, and develop skills in writing and understanding programs. Moreover they contribute to the advancement of science by providing information that will help guide the improvement of the GISSVM and hence of <span class="hlt">ocean</span> and <span class="hlt">climate</span> <span class="hlt">models</span> and ultimately our</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000092882','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000092882"><span>Projected Impact of <span class="hlt">Climate</span> Change on the Water and Salt Budgets of the Arctic <span class="hlt">Ocean</span> by a Global <span class="hlt">Climate</span> <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, James R.; Russell, Gary L.</p> <p>1996-01-01</p> <p>The annual flux of freshwater into the Arctic <span class="hlt">Ocean</span> by the atmosphere and rivers is balanced by the export of sea ice and <span class="hlt">oceanic</span> freshwater. Two 150-year simulations of a global <span class="hlt">climate</span> <span class="hlt">model</span> are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. Relative to the control, the last 50-year period of the GHG experiment indicates that the total inflow of water from the atmosphere and rivers increases by 10% primarily due to an increase in river discharge, the annual sea-ice export decreases by about half, the <span class="hlt">oceanic</span> liquid water export increases, salinity decreases, sea-ice cover decreases, and the total mass and sea-surface height of the Arctic <span class="hlt">Ocean</span> increase. The closed, compact, and multi-phased nature of the hydrologic cycle in the Arctic <span class="hlt">Ocean</span> makes it an ideal test of water budgets that could be included in <span class="hlt">model</span> intercomparisons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSOD13A..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSOD13A..03S"><span>Producing a <span class="hlt">Climate</span>-Quality Database of Global Upper <span class="hlt">Ocean</span> Profile Temperatures - The IQuOD (International Quality-controlled <span class="hlt">Ocean</span> Database) Project.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sprintall, J.; Cowley, R.; Palmer, M. D.; Domingues, C. M.; Suzuki, T.; Ishii, M.; Boyer, T.; Goni, G. J.; Gouretski, V. V.; Macdonald, A. M.; Thresher, A.; Good, S. A.; Diggs, S. C.</p> <p>2016-02-01</p> <p>Historical <span class="hlt">ocean</span> temperature profile observations provide a critical element for a host of <span class="hlt">ocean</span> and <span class="hlt">climate</span> research activities. These include providing initial conditions for seasonal-to-decadal prediction systems, evaluating past variations in sea level and Earth's energy imbalance, <span class="hlt">ocean</span> state estimation for studying variability and change, and <span class="hlt">climate</span> <span class="hlt">model</span> evaluation and development. The International Quality controlled <span class="hlt">Ocean</span> Database (IQuOD) initiative represents a community effort to create the most globally complete temperature profile dataset, with (intelligent) metadata and assigned uncertainties. With an internationally coordinated effort organized by oceanographers, with data and <span class="hlt">ocean</span> instrumentation expertise, and in close consultation with end users (e.g., <span class="hlt">climate</span> <span class="hlt">modelers</span>), the IQuOD initiative will assess and maximize the potential of an irreplaceable collection of <span class="hlt">ocean</span> temperature observations (tens of millions of profiles collected at a cost of tens of billions of dollars, since 1772) to fulfil the demand for a <span class="hlt">climate</span>-quality global database that can be used with greater confidence in a vast range of <span class="hlt">climate</span> change related research and services of societal benefit. Progress towards version 1 of the IQuOD database, ongoing and future work will be presented. More information on IQuOD is available at www.iquod.org.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP41A2212R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP41A2212R"><span><span class="hlt">Climate</span> in the Absence of <span class="hlt">Ocean</span> Heat Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rose, B. E. J.</p> <p>2015-12-01</p> <p>The energy transported by the <span class="hlt">oceans</span> to mid- and high latitudes is small compared to the atmosphere, yet exerts an outsized influence on the <span class="hlt">climate</span>. A key reason is the strong interaction between <span class="hlt">ocean</span> heat transport (OHT) and sea ice extent. I quantify this by comparing a realistic control <span class="hlt">climate</span> simulation with a slab <span class="hlt">ocean</span> simulation in which OHT is disabled. Using the state-of-the-art CESM with a realistic present-day continental configuration, I show that the absence of OHT leads to a 23 K global cooling and massive expansion of sea ice to near 30º latitude in both hemisphere. The ice expansion is asymmetric, with greatest extent in the South Pacific and South Indian <span class="hlt">ocean</span> basins. I discuss implications of this enormous and asymmetric <span class="hlt">climate</span> change for atmospheric circulation, heat transport, and tropical precipitation. Parameter sensitivity studies show that the simulated <span class="hlt">climate</span> is far more sensitive to small changes in ice surface albedo in the absence of OHT, with some perturbations sufficient to cause a runaway Snowball Earth glaciation. I conclude that the <span class="hlt">oceans</span> are responsible for an enormous global warming by mitigating an otherwise very potent sea ice albedo feedback, but that the magnitude of this effect is still rather uncertain. I will also present some ideas on adapting the simple energy balance <span class="hlt">model</span> to account for the enhanced sensitivity of sea ice to heating from the <span class="hlt">ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC21C0548C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC21C0548C"><span>Sensitivity of <span class="hlt">Ocean</span> Chemistry and Oxygen Change to the Uncertainty in <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, L.; Wang, S.; Zheng, M.; Zhang, H.</p> <p>2014-12-01</p> <p>With increasing atmospheric CO2 and <span class="hlt">climate</span> change, global <span class="hlt">ocean</span> is undergoing substantial physical and biogeochemical changes. In particular, changes in <span class="hlt">ocean</span> oxygen and carbonate chemistry have great implication for marine biota. There is considerable uncertainty in the projections of future <span class="hlt">climate</span> change, and it is unclear how the uncertainty in <span class="hlt">climate</span> change would affect the projection of <span class="hlt">ocean</span> oxygen and carbonate chemistry. To examine the effect of <span class="hlt">climate</span> change on <span class="hlt">ocean</span> oxygen and carbonate chemistry, we used an Earth system <span class="hlt">model</span> of intermediate complexity to perform simulations that are driven by atmospheric CO2 concentration pathway of RCP 8.5 with <span class="hlt">climate</span> sensitivity varying from 0.0°C to 4.5 °C. <span class="hlt">Climate</span> change affects carbonate chemistry and oxygen mainly through its impact on <span class="hlt">ocean</span> temperature, <span class="hlt">ocean</span> ventilation, and concentration of dissolved inorganic carbon and alkalinity. Our simulations show that <span class="hlt">climate</span> change mitigates the decrease of carbonate ions at the <span class="hlt">ocean</span> surface but has negligible effect on surface <span class="hlt">ocean</span> pH. Averaged over the whole <span class="hlt">ocean</span>, <span class="hlt">climate</span> change acts to decrease oxygen concentration but mitigates the CO2-induced reduction of carbonate ion and pH. In our simulations, by year 2500, every degree increase of <span class="hlt">climate</span> sensitivity warms the <span class="hlt">ocean</span> by 0.8 °C and reduces <span class="hlt">ocean</span>-mean dissolved oxygen concentration by 5.0%. Meanwhile, every degree increase of <span class="hlt">climate</span> sensitivity buffers CO2-induced reduction in <span class="hlt">ocean</span>-mean carbonate ion concentration and pH by 3.4% and 0.02 units, respectively. Our study demonstrates different sensitivities of <span class="hlt">ocean</span> temperature, carbonate chemistry, and oxygen, in terms of both the sign and magnitude, to the amount of <span class="hlt">climate</span> change, which have great implications for understanding the response of <span class="hlt">ocean</span> biota to <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890042909&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890042909&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Sensitivity of <span class="hlt">climate</span> and atmospheric CO2 to deep-<span class="hlt">ocean</span> and shallow-<span class="hlt">ocean</span> carbonate burial</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Volk, Tyler</p> <p>1989-01-01</p> <p>A <span class="hlt">model</span> of the carbonate-silicate geochemical cycle is presented that distinguishes carbonate masses produced by shallow-<span class="hlt">ocean</span> and deep-<span class="hlt">ocean</span> carbonate burial and shows that reasonable increases in deep-<span class="hlt">ocean</span> burial could produce substantial warmings over a few hundred million years. The <span class="hlt">model</span> includes exchanges between crust and mantle; transients from burial shifts are found to be sensitive to the fraction of nondegassed carbonates subducted into the mantle. Without the habitation of the open <span class="hlt">ocean</span> by plankton such as foraminifera and coccolithophores, today's <span class="hlt">climate</span> would be substantially colder.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002122','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002122"><span>Natural Air-Sea Flux of CO2 in Simulations of the NASA-GISS <span class="hlt">Climate</span> <span class="hlt">Model</span>: Sensitivity to the Physical <span class="hlt">Ocean</span> <span class="hlt">Model</span> Formulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Romanou, A.; Gregg, Watson W.; Romanski, J.; Kelley, M.; Bleck, R.; Healy, R.; Nazarenko, L.; Russell, G.; Schmidt, G. A.; Sun, S.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150002122'); toggleEditAbsImage('author_20150002122_show'); toggleEditAbsImage('author_20150002122_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150002122_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150002122_hide"></p> <p>2013-01-01</p> <p>Results from twin control simulations of the preindustrial CO2 gas exchange (natural flux of CO2) between the <span class="hlt">ocean</span> and the atmosphere are presented here using the NASA-GISS <span class="hlt">climate</span> <span class="hlt">model</span>, in which the same atmospheric component (<span class="hlt">modelE</span>2) is coupled to two different <span class="hlt">ocean</span> <span class="hlt">models</span>, the Russell <span class="hlt">ocean</span> <span class="hlt">model</span> and HYCOM. Both incarnations of the GISS <span class="hlt">climate</span> <span class="hlt">model</span> are also coupled to the same <span class="hlt">ocean</span> biogeochemistry module (NOBM) which estimates prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2. <span class="hlt">Model</span> intercomparison is carried out at equilibrium conditions and <span class="hlt">model</span> differences are contrasted with biases from present day climatologies. Although the <span class="hlt">models</span> agree on the spatial patterns of the air-sea flux of CO2, they disagree on the strength of the North Atlantic and Southern <span class="hlt">Ocean</span> sinks mainly because of kinematic (winds) and chemistry (pCO2) differences rather than thermodynamic (SST) ones. Biology/chemistry dissimilarities in the <span class="hlt">models</span> stem from the different parameterizations of advective and diffusive processes, such as overturning, mixing and horizontal tracer advection and to a lesser degree from parameterizations of biogeochemical processes such as gravitational settling and sinking. The global meridional overturning circulation illustrates much of the different behavior of the biological pump in the two <span class="hlt">models</span>, together with differences in mixed layer depth which are responsible for different SST, DIC and nutrient distributions in the two <span class="hlt">models</span> and consequently different atmospheric feedbacks (in the wind, net heat and freshwater fluxes into the <span class="hlt">ocean</span>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24784218','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24784218"><span>North Atlantic forcing of tropical Indian <span class="hlt">Ocean</span> <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mohtadi, Mahyar; Prange, Matthias; Oppo, Delia W; De Pol-Holz, Ricardo; Merkel, Ute; Zhang, Xiao; Steinke, Stephan; Lückge, Andreas</p> <p>2014-05-01</p> <p>The response of the tropical <span class="hlt">climate</span> in the Indian <span class="hlt">Ocean</span> realm to abrupt <span class="hlt">climate</span> change events in the North Atlantic <span class="hlt">Ocean</span> is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells, but the dearth of high-resolution records outside the monsoon realm in the Indian <span class="hlt">Ocean</span> precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian <span class="hlt">Ocean</span> hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian <span class="hlt">Ocean</span>. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian <span class="hlt">Ocean</span> for the past 45,000 years, combined with <span class="hlt">climate</span> <span class="hlt">model</span> simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian <span class="hlt">Ocean</span> hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian <span class="hlt">Ocean</span> realm and wet and warm conditions in the southern realm during North Atlantic cold spells.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213972P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213972P"><span>Nudging atmosphere and <span class="hlt">ocean</span> reanalyses for seasonal <span class="hlt">climate</span> predictions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piontek, Robert; Baehr, Johanna; Kornblueh, Luis; Müller, Wolfgang Alexander; Haak, Helmuth; Botzet, Michael; Matei, Daniela</p> <p>2010-05-01</p> <p>Seasonal <span class="hlt">climate</span> forecasts based on state-of-the-art <span class="hlt">climate</span> <span class="hlt">models</span> have been developed recently. Here, we critically discuss the obstacles encountered in the setup of the ECHAM6/MPIOM global coupled <span class="hlt">climate</span> <span class="hlt">model</span> to perform <span class="hlt">climate</span> predictions on seasonal to decadal time scales. We particularly focus on the initialization procedure, especially on the implementation of the nudging scheme, in which different reanalysis products are used in the atmosphere (e.g.ERA40), and the <span class="hlt">ocean</span> (e.g., GECCO). Nudging in the atmosphere appears to be sensitive to the following choices: limiting the spectral range of nudging, whether or not temperature is nudged, the strength of the nudging coefficient for surface pressure, and the height at which the planetary boundary layer is excluded from nudging. We find that including nudging in both the atmosphere and the <span class="hlt">ocean</span> gives improved results over nudging only the <span class="hlt">ocean</span> or the atmosphere. For the implementation of the nudging in the atmosphere, we find the most significant improvements in the solution when either the planetary boundary layer is excluded, or if nudging of temperature is omitted. There are significant improvements in the solution when resolution is increased in both the atmosphere and in the <span class="hlt">ocean</span>. Our tests form the basis for the prediction system introduced in the abstract of Müller et al., where hindcasts are analysed as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS41B1711W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS41B1711W"><span>Realism of the Indian <span class="hlt">Ocean</span> Dipole in CMIP5 <span class="hlt">models</span>, and the Implication for <span class="hlt">Climate</span> Projections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weller, E.; Cai, W.; Cowan, T.</p> <p>2012-12-01</p> <p>An assessment of how well <span class="hlt">climate</span> <span class="hlt">models</span> simulate the Indian <span class="hlt">Ocean</span> Dipole (IOD) is undertaken using coupled <span class="hlt">models</span> that have partaken in the Coupled <span class="hlt">Model</span> Intercomparison Project Phase 5 (CMIP5). Compared to CMIP3 <span class="hlt">models</span>, no substantial improvement is evident in the simulation of the IOD pattern and/or amplitude during its peak season in austral spring (September-October-November, or SON). The majority of CMIP5 <span class="hlt">models</span> generate a larger variance of sea surface temperature (SST) in the Sumatra-Java upwelling region and an IOD amplitude that is far greater than what is observed. Although the relationship between precipitation and the tropical Indian <span class="hlt">Ocean</span> SST is well simulated, future projections of SON rainfall changes over IOD-influenced regions are intrinsically linked to the IOD-rainfall teleconnection and IOD amplitude in the <span class="hlt">model</span> present-day <span class="hlt">climate</span>. The diversity of the simulated IOD amplitudes in CMIP5 (and CMIP3) <span class="hlt">models</span> which tend to be overly large, results in a wide range of future <span class="hlt">modelled</span> SON rainfall trends over IOD-influenced regions. Our results highlight the importance of realistically simulating the present-day IOD properties and the caveat that needs to be exercised in interpreting <span class="hlt">climate</span> projections in the IOD-affected regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..4312543B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..4312543B"><span>Spread in the magnitude of <span class="hlt">climate</span> <span class="hlt">model</span> interdecadal global temperature variability traced to disagreements over high-latitude <span class="hlt">oceans</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Patrick T.; Li, Wenhong; Jiang, Jonathan H.; Su, Hui</p> <p>2016-12-01</p> <p>Unforced variability in global mean surface air temperature can obscure or exaggerate global warming on interdecadal time scales; thus, understanding both the magnitude and generating mechanisms of such variability is of critical importance for both attribution studies as well as decadal <span class="hlt">climate</span> prediction. Coupled atmosphere-<span class="hlt">ocean</span> general circulation <span class="hlt">models</span> (<span class="hlt">climate</span> <span class="hlt">models</span>) simulate a wide range of magnitudes of unforced interdecadal variability in global mean surface air temperature (UITglobal), hampering efforts to quantify the influence of UITglobal on contemporary global temperature trends. Recently, a preliminary consensus has emerged that unforced interdecadal variability in local surface temperatures (UITlocal) over the tropical Pacific <span class="hlt">Ocean</span> is particularly influential on UITglobal. Therefore, a reasonable hypothesis might be that the large spread in the magnitude of UITglobal across <span class="hlt">climate</span> <span class="hlt">models</span> can be explained by the spread in the magnitude of simulated tropical Pacific UITlocal. Here we show that this hypothesis is mostly false. Instead, the spread in the magnitude of UITglobal is linked much more strongly to the spread in the magnitude of UITlocal over high-latitude regions characterized by significant variability in <span class="hlt">oceanic</span> convection, sea ice concentration, and energy flux at both the surface and the top of the atmosphere. Thus, efforts to constrain the <span class="hlt">climate</span> <span class="hlt">model</span> produced range of UITglobal magnitude would be best served by focusing on the simulation of air-sea interaction at high latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24254799','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24254799"><span>Global <span class="hlt">ocean</span> monitoring for the World <span class="hlt">Climate</span> Research Programme.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Revelle, R; Bretherton, F</p> <p>1986-07-01</p> <p><span class="hlt">Oceanic</span> research and <span class="hlt">modelling</span> for the World <span class="hlt">Climate</span> Research Program will utilize several recently-developed instruments and measuring techniques as well as well-tested, long-used instruments. <span class="hlt">Ocean</span>-scanning satellites will map the component of the <span class="hlt">ocean</span>-surface topography related to <span class="hlt">ocean</span> currents and mesoscale eddies and to fluctuating water volumes caused by <span class="hlt">ocean</span> warming and cooling. Other satellite instruments will measure the direction and magnitude of wind stress on the sea surface, surface water temperatures, the distribution of chlorophyll and other photosynthetic pigments, the characteristics of internal waves, and possible precipitation over the <span class="hlt">ocean</span>. Networks of acoustic transponders will obtain a three-dimensional picture of the distribution of temperature from the surface down to mid-depth and of long-term changes in temperature at depth. <span class="hlt">Ocean</span> research vessels will determine the distribution and fate of geochemical tracers and will also make high-precision, deep hydrographic casts. Ships of opportunity, using expendable instruments, will measure temperature, salinity and currents in the upper water layers. Drifting and anchored buoys will also measure these properties as well as those of the air above the sea surface. Tide gauges installed on islands and exposed coastal locations will measure variations in monthly and shorter-period mean sea level. These tide gauges will provide 'ground truth' for the satellite maps of sea-surface topography, and will also determine variations in <span class="hlt">ocean</span> currents and temperature.All these instruments will be used in several major programs, the most ambitious of which is the World <span class="hlt">Ocean</span> Circulation Experiment (WOCE) designed to obtain global measurements of major currents throughout the world <span class="hlt">ocean</span>, greater understanding of the transformation of water masses, and the role of advective, convective, and turbulent processes in exchange of properties between surface and deep-<span class="hlt">ocean</span> layers.A five- to ten-year experiment</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40.1409H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40.1409H"><span>Southern <span class="hlt">Ocean</span> bottom water characteristics in CMIP5 <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heuzé, CéLine; Heywood, Karen J.; Stevens, David P.; Ridley, Jeff K.</p> <p>2013-04-01</p> <p>Southern <span class="hlt">Ocean</span> deep water properties and formation processes in <span class="hlt">climate</span> <span class="hlt">models</span> are indicative of their capability to simulate future <span class="hlt">climate</span>, heat and carbon uptake, and sea level rise. Southern <span class="hlt">Ocean</span> temperature and density averaged over 1986-2005 from 15 CMIP5 (Coupled <span class="hlt">Model</span> Intercomparison Project Phase 5) <span class="hlt">climate</span> <span class="hlt">models</span> are compared with an observed climatology, focusing on bottom water. Bottom properties are reasonably accurate for half the <span class="hlt">models</span>. Ten <span class="hlt">models</span> create dense water on the Antarctic shelf, but it mixes with lighter water and is not exported as bottom water as in reality. Instead, most <span class="hlt">models</span> create deep water by open <span class="hlt">ocean</span> deep convection, a process occurring rarely in reality. <span class="hlt">Models</span> with extensive deep convection are those with strong seasonality in sea ice. Optimum bottom properties occur in <span class="hlt">models</span> with deep convection in the Weddell and Ross Gyres. Bottom Water formation processes are poorly represented in <span class="hlt">ocean</span> <span class="hlt">models</span> and are a key challenge for improving <span class="hlt">climate</span> predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992JGR....97.9435H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992JGR....97.9435H"><span>A two-dimensional <span class="hlt">ocean</span> <span class="hlt">model</span> for long-term <span class="hlt">climatic</span> simulations: Stability and coupling to atmospheric and sea ice <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harvey, L. D. Danny</p> <p>1992-06-01</p> <p>A two-dimensional (latitude-depth) deep <span class="hlt">ocean</span> <span class="hlt">model</span> is presented which is coupled to a sea ice <span class="hlt">model</span> and an Energy Balance <span class="hlt">Climate</span> <span class="hlt">Model</span> (EBCM), the latter having land-sea and surface-air resolution. The processes which occur in the <span class="hlt">ocean</span> <span class="hlt">model</span> are thermohaline overturning driven by the horizontal density gradient, shallow wind-driven overturning cells, convective overturning, and vertical and horizontal diffusion of heat and salt. The density field is determined from the temperature and salinity fields using a nonlinear equation of state. Mixed layer salinity is affected by evaporation, precipitation, runoff from continents, and sea ice freezing and melting, as well as by advective, convective, and diffusive exchanges with the deep <span class="hlt">ocean</span>. The <span class="hlt">ocean</span> <span class="hlt">model</span> is first tested in an uncoupled mode, in which hemispherically symmetric mixed layer temperature and salinity, or salinity flux, are specified as upper boundary conditions. An experiment performed with previous <span class="hlt">models</span> is repeated in which a mixed layer salinity perturbation is introduced in the polar half of one hemisphere after switching from a fixed salinity to a fixed salinity flux boundary condition. For small values of the vertical diffusion coefficient KV, the <span class="hlt">model</span> undergoes self-sustained oscillations with a period of about 1500 years. With larger values of KV, the <span class="hlt">model</span> locks into either an asymmetric mode with a single overturning cell spanning both hemispheres, or a symmetric quiescent state with downwelling near the equator, upwelling at high latitudes, and a warm deep <span class="hlt">ocean</span> (depending on the value of KV). When the <span class="hlt">ocean</span> <span class="hlt">model</span> is forced with observed mixed layer temperature and salinity, no oscillations occur. The <span class="hlt">model</span> successfully simulates the very weak meridional overturning and strong Antarctic Circumpolar Current at the latitudes of the Drake Passage. The coupled EBCM-deep <span class="hlt">ocean</span> <span class="hlt">model</span> displays internal oscillations with a period of 3000 years if the <span class="hlt">ocean</span> fraction is uniform with latitude and KV</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010545','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010545"><span>Impacts of Atmosphere-<span class="hlt">Ocean</span> Coupling on Southern Hemisphere <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Feng; Newman, Paul; Pawson, Steven</p> <p>2013-01-01</p> <p><span class="hlt">Climate</span> in the Southern Hemisphere (SH) has undergone significant changes in recent decades. These changes are closely linked to the shift of the Southern Annular Mode (SAM) towards its positive polarity, which is driven primarily by Antarctic ozone depletion. There is growing evidence that Antarctic ozone depletion has significant impacts on Southern <span class="hlt">Ocean</span> circulation change. However, it is poorly understood whether and how <span class="hlt">ocean</span> feedback might impact the SAM and <span class="hlt">climate</span> change in the SH atmosphere. This outstanding science question is investigated using the Goddard Earth Observing System Coupled Atmosphere-<span class="hlt">Ocean</span>-Chemistry <span class="hlt">Climate</span> <span class="hlt">Model</span>(GEOS-AOCCM).We perform ensemble simulations of the recent past (1960-2010) with and without the interactive <span class="hlt">ocean</span>. For simulations without the interactive <span class="hlt">ocean</span>, we use sea surface temperatures and sea ice concentrations produced by the interactive <span class="hlt">ocean</span> simulations. The differences between these two ensemble simulations quantify the effects of atmosphere-<span class="hlt">ocean</span> coupling. We will investigate the impacts of atmosphere-<span class="hlt">ocean</span> coupling on stratospheric processes such as Antarctic ozone depletion and Antarctic polar vortex breakup. We will address whether <span class="hlt">ocean</span> feedback affects Rossby wave generation in the troposphere and wave propagation into the stratosphere. Another focuson this study is to assess how <span class="hlt">ocean</span> feedback might affect the tropospheric SAM response to Antarctic ozone depletion</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19901326','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19901326"><span><span class="hlt">Climate</span>, carbon cycling, and deep-<span class="hlt">ocean</span> ecosystems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smith, K L; Ruhl, H A; Bett, B J; Billett, D S M; Lampitt, R S; Kaufmann, R S</p> <p>2009-11-17</p> <p><span class="hlt">Climate</span> variation affects surface <span class="hlt">ocean</span> processes and the production of organic carbon, which ultimately comprises the primary food supply to the deep-sea ecosystems that occupy approximately 60% of the Earth's surface. Warming trends in atmospheric and upper <span class="hlt">ocean</span> temperatures, attributed to anthropogenic influence, have occurred over the past four decades. Changes in upper <span class="hlt">ocean</span> temperature influence stratification and can affect the availability of nutrients for phytoplankton production. Global warming has been predicted to intensify stratification and reduce vertical mixing. Research also suggests that such reduced mixing will enhance variability in primary production and carbon export flux to the deep sea. The dependence of deep-sea communities on surface water production has raised important questions about how <span class="hlt">climate</span> change will affect carbon cycling and deep-<span class="hlt">ocean</span> ecosystem function. Recently, unprecedented time-series studies conducted over the past two decades in the North Pacific and the North Atlantic at >4,000-m depth have revealed unexpectedly large changes in deep-<span class="hlt">ocean</span> ecosystems significantly correlated to <span class="hlt">climate</span>-driven changes in the surface <span class="hlt">ocean</span> that can impact the global carbon cycle. <span class="hlt">Climate</span>-driven variation affects <span class="hlt">oceanic</span> communities from surface waters to the much-overlooked deep sea and will have impacts on the global carbon cycle. Data from these two widely separated areas of the deep <span class="hlt">ocean</span> provide compelling evidence that changes in <span class="hlt">climate</span> can readily influence deep-sea processes. However, the limited geographic coverage of these existing time-series studies stresses the importance of developing a more global effort to monitor deep-sea ecosystems under modern conditions of rapidly changing <span class="hlt">climate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20160006514&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dclimate%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20160006514&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dclimate%2Bchange"><span>Large-Scale <span class="hlt">Ocean</span> Circulation-Cloud Interactions Reduce the Pace of Transient <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Trossman, D. S.; Palter, J. B.; Merlis, T. M.; Huang, Y.; Xia, Y.</p> <p>2016-01-01</p> <p>Changes to the large scale <span class="hlt">oceanic</span> circulation are thought to slow the pace of transient <span class="hlt">climate</span> change due, in part, to their influence on radiative feedbacks. Here we evaluate the interactions between CO2-forced perturbations to the large-scale <span class="hlt">ocean</span> circulation and the radiative cloud feedback in a <span class="hlt">climate</span> <span class="hlt">model</span>. Both the change of the <span class="hlt">ocean</span> circulation and the radiative cloud feedback strongly influence the magnitude and spatial pattern of surface and <span class="hlt">ocean</span> warming. Changes in the <span class="hlt">ocean</span> circulation reduce the amount of transient global warming caused by the radiative cloud feedback by helping to maintain low cloud coverage in the face of global warming. The radiative cloud feedback is key in affecting atmospheric meridional heat transport changes and is the dominant radiative feedback mechanism that responds to <span class="hlt">ocean</span> circulation change. Uncertainty in the simulated <span class="hlt">ocean</span> circulation changes due to CO2 forcing may contribute a large share of the spread in the radiative cloud feedback among <span class="hlt">climate</span> <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A21F2211K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A21F2211K"><span>Can decadal <span class="hlt">climate</span> predictions be improved by <span class="hlt">ocean</span> ensemble dispersion filtering?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kadow, C.; Illing, S.; Kröner, I.; Ulbrich, U.; Cubasch, U.</p> <p>2017-12-01</p> <p>Decadal predictions by Earth system <span class="hlt">models</span> aim to capture the state and phase of the <span class="hlt">climate</span> several years inadvance. Atmosphere-<span class="hlt">ocean</span> interaction plays an important role for such <span class="hlt">climate</span> forecasts. While short-termweather forecasts represent an initial value problem and long-term <span class="hlt">climate</span> projections represent a boundarycondition problem, the decadal <span class="hlt">climate</span> prediction falls in-between these two time scales. The <span class="hlt">ocean</span> memorydue to its heat capacity holds big potential skill on the decadal scale. In recent years, more precise initializationtechniques of coupled Earth system <span class="hlt">models</span> (incl. atmosphere and <span class="hlt">ocean</span>) have improved decadal predictions.Ensembles are another important aspect. Applying slightly perturbed predictions results in an ensemble. Insteadof using and evaluating one prediction, but the whole ensemble or its ensemble average, improves a predictionsystem. However, <span class="hlt">climate</span> <span class="hlt">models</span> in general start losing the initialized signal and its predictive skill from oneforecast year to the next. Here we show that the <span class="hlt">climate</span> prediction skill of an Earth system <span class="hlt">model</span> can be improvedby a shift of the <span class="hlt">ocean</span> state toward the ensemble mean of its individual members at seasonal intervals. Wefound that this procedure, called ensemble dispersion filter, results in more accurate results than the standarddecadal prediction. Global mean and regional temperature, precipitation, and winter cyclone predictions showan increased skill up to 5 years ahead. Furthermore, the novel technique outperforms predictions with largerensembles and higher resolution. Our results demonstrate how decadal <span class="hlt">climate</span> predictions benefit from oceanensemble dispersion filtering toward the ensemble mean. This study is part of MiKlip (fona-miklip.de) - a major project on decadal <span class="hlt">climate</span> prediction in Germany.We focus on the Max-Planck-Institute Earth System <span class="hlt">Model</span> using the low-resolution version (MPI-ESM-LR) andMiKlip's basic initialization strategy as in 2017 published decadal <span class="hlt">climate</span> forecast: http</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29610313','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29610313"><span>Constraining the <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH of the early Earth with a geological carbon cycle <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Krissansen-Totton, Joshua; Arney, Giada N; Catling, David C</p> <p>2018-04-17</p> <p>The early Earth's environment is controversial. <span class="hlt">Climatic</span> estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early <span class="hlt">climate</span> and <span class="hlt">ocean</span> chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle <span class="hlt">model</span> with <span class="hlt">ocean</span> chemistry to calculate self-consistent histories of <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH. Our carbon cycle <span class="hlt">model</span> includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean <span class="hlt">climate</span> was likely temperate (0-50 °C) due to the combined negative feedbacks of continental and seafloor weathering. <span class="hlt">Ocean</span> pH evolves monotonically from [Formula: see text] (2σ) at 4.0 Ga to [Formula: see text] (2σ) at the Archean-Proterozoic boundary, and to [Formula: see text] (2σ) at the Proterozoic-Phanerozoic boundary. This evolution is driven by the secular decline of pCO 2 , which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. Copyright © 2018 the Author(s). Published by PNAS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060035754&hterms=Wang+Chao&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DWang%252C%2BChao','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060035754&hterms=Wang+Chao&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DWang%252C%2BChao"><span><span class="hlt">Ocean</span> <span class="hlt">Modeling</span> and Visualization on Massively Parallel Computer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chao, Yi; Li, P. Peggy; Wang, Ping; Katz, Daniel S.; Cheng, Benny N.</p> <p>1997-01-01</p> <p><span class="hlt">Climate</span> <span class="hlt">modeling</span> is one of the grand challenges of computational science, and <span class="hlt">ocean</span> <span class="hlt">modeling</span> plays an important role in both understanding the current <span class="hlt">climatic</span> conditions and predicting future <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950051814&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950051814&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Century/millennium internal <span class="hlt">climate</span> oscillations in an <span class="hlt">ocean</span>-atmosphere-continental ice sheet <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Birchfield, Edward G.; Wang, Huaxiao; Rich, Jonathan J.</p> <p>1994-01-01</p> <p>We demonstrate in a simple <span class="hlt">climate</span> <span class="hlt">model</span> that there exist nonlinear feedbacks between the atmosphere, <span class="hlt">ocean</span>, and ice sheets capable of producing century/millennium timescale internal oscillations resembling those seen in the paleoclimate record. Feedbacks involve meridional heat and salt transports in the North Atlantic, surface <span class="hlt">ocean</span> freshwater fluxes associated with melting and growing continental ice sheets in the northen hemisphere and with Atlantic to Pacific water vapor transport. The positive feedback between the production of North Atlantic Deep Water (NADW) and the meridional salt transport by the Atlantic thermohaline circulation tends to destabilize the <span class="hlt">climate</span> system, while the negative feedback between the freshwater flux, either to or from the continental ice sheets, and meridional heat flux to the high-latitude North Atlantic, accomplished by the thermohaline circulation, stabilizes the system. The thermohaline circulation plays a central role in both positive and negative feedbacks because of its transport of both heat and salt. Because of asymmetries between the growth and melt phases the oscillations are, in general, accompanied by a growing or decreasing ice volume over each cycle, which in the <span class="hlt">model</span> is reflected by increasing or decreasing mean salinity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A44D..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A44D..06G"><span>A Mixed Phase Tale: New Ways of using in-situ cloud observations to reduce <span class="hlt">climate</span> <span class="hlt">model</span> biases in Southern <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gettelman, A.; Stith, J. L.</p> <p>2014-12-01</p> <p>Southern <span class="hlt">ocean</span> clouds are a critical part of the earth's energy budget, and significant biases in the climatology of these clouds exist in <span class="hlt">models</span> used to predict <span class="hlt">climate</span> change. We compare in situ measurements of cloud microphysical properties of ice and liquid over the S. <span class="hlt">Ocean</span> with constrained output from the atmospheric component of an Earth System <span class="hlt">Model</span>. Observations taken during the HIAPER (the NSF/NCAR G-V aircraft) Pole-to-Pole Observations (HIPPO) multi-year field campaign are compared with simulations from the atmospheric component of the Community Earth System <span class="hlt">Model</span> (CESM). Remarkably, CESM is able to accurately simulate the locations of cloud formation, and even cloud microphysical properties are comparable between the <span class="hlt">model</span> and observations. Significantly, the simulations do not predict sufficient supercooled liquid. Altering the <span class="hlt">model</span> cloud and aerosol processes to better reproduce the observations of supercooled liquid acts to reduce long-standing biases in S. <span class="hlt">Ocean</span> clouds in CESM, which are typical of other <span class="hlt">models</span>. Furthermore, sensitivity tests show where better observational constraints on aerosols and cloud microphysics can reduce uncertainty and biases in global <span class="hlt">models</span>. These results are intended to show how we can connect large scale simulations with field observations in the S. <span class="hlt">Ocean</span> to better understand Southern <span class="hlt">Ocean</span> cloud processes and reduce biases in global <span class="hlt">climate</span> simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMOS24A..03P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMOS24A..03P"><span>An overview of the South Atlantic <span class="hlt">Ocean</span> <span class="hlt">climate</span> variability and air-sea interaction processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pezzi, L. P.; Parise, C. K.; Souza, R.; Gherardi, D. F.; Camargo, R.; Soares, H. C.; Silveira, I.</p> <p>2013-05-01</p> <p>The <span class="hlt">Ocean</span> <span class="hlt">Modeling</span> Group at the National Institute of Space Research (INPE) in Brazil has been developing several studies to understand the role of the Atlantic <span class="hlt">ocean</span> on the South America <span class="hlt">climate</span>. Studies include simulating the dynamics of the Tropical South-Atlantic <span class="hlt">Ocean</span> and Southern <span class="hlt">Ocean</span>. This is part of an ongoing international cooperation, in which Brazil participates with in situ observations, numerical <span class="hlt">modeling</span> and statistical analyses. We have focused on the understanding of the impacts of extreme weather events over the Tropical South Atlantic <span class="hlt">Ocean</span> and their prediction on different time-scales. One such study is aimed at analyzing the <span class="hlt">climate</span> signal generated by imposing an extreme condition on the Antarctic sea ice and considering different complexities of the sea ice <span class="hlt">model</span>. The influence of the Brazil-Malvinas Confluence (BMC) region on the marine atmospheric boundary layer (MABL) is also investigated through in situ data analysis of different cruises and numerical experiments with a regional numerical <span class="hlt">model</span>. There is also an ongoing investigation that revealed basin-scale interannual <span class="hlt">climate</span> variation with impacts on the Brazilian Large Marine Ecosystems (LMEs), which are strongly correlated with <span class="hlt">climate</span> indices such as ENSO, AAO and PDO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.1533W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.1533W"><span>The response of the southwest Western Australian wave <span class="hlt">climate</span> to Indian <span class="hlt">Ocean</span> <span class="hlt">climate</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wandres, Moritz; Pattiaratchi, Charitha; Hetzel, Yasha; Wijeratne, E. M. S.</p> <p>2018-03-01</p> <p>Knowledge of regional wave <span class="hlt">climates</span> is critical for coastal planning, management, and protection. In order to develop a regional wave <span class="hlt">climate</span>, it is important to understand the atmospheric systems responsible for wave generation. This study examines the variability of the southwest Western Australian (SWWA) shelf and nearshore wind wave <span class="hlt">climate</span> and its relationship to southern hemisphere <span class="hlt">climate</span> variability represented by various atmospheric indices: the southern oscillation index (SOI), the Southern Annular Mode (SAM), the Indian <span class="hlt">Ocean</span> Dipole Mode Index (DMI), the Indian <span class="hlt">Ocean</span> Subtropical Dipole (IOSD), the latitudinal position of the subtropical high-pressure ridge (STRP), and the corresponding intensity of the subtropical ridge (STRI). A 21-year wave hindcast (1994-2014) of the SWWA continental shelf was created using the third generation wave <span class="hlt">model</span> Simulating WAves Nearshore (SWAN), to analyse the seasonal and inter-annual wave <span class="hlt">climate</span> variability and its relationship to the atmospheric regime. Strong relationships between wave heights and the STRP and the STRI, a moderate correlation between the wave <span class="hlt">climate</span> and the SAM, and no significant correlation between SOI, DMI, and IOSD and the wave <span class="hlt">climate</span> were found. Strong spatial, seasonal, and inter-annual variability, as well as seasonal longer-term trends in the mean wave <span class="hlt">climate</span> were studied and linked to the latitudinal changes in the subtropical high-pressure ridge and the Southern <span class="hlt">Ocean</span> storm belt. As the Southern <span class="hlt">Ocean</span> storm belt and the subtropical high-pressure ridge shifted southward (northward) wave heights on the SWWA shelf region decreased (increased). The wave height anomalies appear to be driven by the same atmospheric conditions that influence rainfall variability in SWWA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.8198M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.8198M"><span>Change of <span class="hlt">ocean</span> circulation in the East Asian Marginal Seas under different <span class="hlt">climate</span> conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Min, Hong Sik; Kim, Cheol-Ho; Kim, Young Ho</p> <p>2010-05-01</p> <p>Global <span class="hlt">climate</span> <span class="hlt">models</span> do not properly resolve an <span class="hlt">ocean</span> environment in the East Asian Marginal Seas (EAMS), which is mainly due to a poor representation of the topography in continental shelf region and a coarse spatial resolution. To examine a possible change of <span class="hlt">ocean</span> environment under global warming in the EAMS, therefore we used North Pacific Regional <span class="hlt">Ocean</span> <span class="hlt">Model</span>. The regional <span class="hlt">model</span> was forced by atmospheric conditions extracted from the simulation results of the global <span class="hlt">climate</span> <span class="hlt">models</span> for the 21st century projected by the IPCC SRES A1B scenario as well as the 20th century. The North Pacific Regional <span class="hlt">Ocean</span> <span class="hlt">model</span> simulated a detailed pattern of temperature change in the EAMS showing locally different rising or falling trend under the future <span class="hlt">climate</span> condition, while the global <span class="hlt">climate</span> <span class="hlt">models</span> simulated a simple pattern like an overall increase. Changes of circulation pattern in the EAMS such as an intrusion of warm water into the Yellow Sea as well as the Kuroshio were also well resolved. Annual variations in volume transports through the Taiwan Strait and the Korea Strait under the future condition were simulated to be different from those under present condition. Relative ratio of volume transport through the Soya Strait to the Tsugaru Strait also responded to the <span class="hlt">climate</span> condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS41A1541G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS41A1541G"><span>Spice: Southwest Pacific <span class="hlt">Ocean</span> Circulation and <span class="hlt">Climate</span> Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganachaud, A. S.; Melet, A.; Maes, C.</p> <p>2010-12-01</p> <p>South Pacific <span class="hlt">oceanic</span> waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern <span class="hlt">Ocean</span>. The transit in the Coral Sea is potentially of great importance to tropical <span class="hlt">climate</span> prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale <span class="hlt">climate</span> feedbacks. The south branch is associated with comparable impacts in the Tasman Sea area. The Southwest Pacific is a region of complex circulation, with the SEC splitting in strong zonal jets upon encountering island archipelagos. Those jets partition on the Australian eastern boundary to feed the East Australian Current for the southern branch and the North Queensland Current and eventually the Equatorial Undercurrent for the northern branch. On average, the <span class="hlt">oceanic</span> circulation is driven by the Trade Winds, and subject to substantial variability, related with the South Pacific Convergence Zone (SPCZ) position and intensity. The circulation, and its influence on remote and regional <span class="hlt">climate</span>, is poorly understood due to the lack of appropriate measurements. <span class="hlt">Ocean</span> and atmosphere scientists from Australia, France, New Zealand, the United States and Pacific Island countries initiated an international research project under the auspices of CLIVAR to comprehend the southwest Pacific <span class="hlt">Ocean</span> circulation and its direct and indirect influence on the <span class="hlt">climate</span> and environment. SPICE is a regionally-coordinated experiment to measure, study and monitor the <span class="hlt">ocean</span> circulation and the SPCZ, to validate and improve numerical <span class="hlt">models</span>, and to integrate with assimilating systems. This ongoing project reflects a strong sense that substantial progress can be made through collaboration among South Pacific national research groups, coordinated with broader South Pacific projects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5910859','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5910859"><span>Constraining the <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH of the early Earth with a geological carbon cycle <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Krissansen-Totton, Joshua; Arney, Giada N.</p> <p>2018-01-01</p> <p>The early Earth’s environment is controversial. <span class="hlt">Climatic</span> estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early <span class="hlt">climate</span> and <span class="hlt">ocean</span> chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle <span class="hlt">model</span> with <span class="hlt">ocean</span> chemistry to calculate self-consistent histories of <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH. Our carbon cycle <span class="hlt">model</span> includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean <span class="hlt">climate</span> was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. <span class="hlt">Ocean</span> pH evolves monotonically from 6.6−0.4+0.6 (2σ) at 4.0 Ga to 7.0−0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9−0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. PMID:29610313</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PNAS..115.4105K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PNAS..115.4105K"><span>Constraining the <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH of the early Earth with a geological carbon cycle <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krissansen-Totton, Joshua; Arney, Giada N.; Catling, David C.</p> <p>2018-04-01</p> <p>The early Earth’s environment is controversial. <span class="hlt">Climatic</span> estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early <span class="hlt">climate</span> and <span class="hlt">ocean</span> chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle <span class="hlt">model</span> with <span class="hlt">ocean</span> chemistry to calculate self-consistent histories of <span class="hlt">climate</span> and <span class="hlt">ocean</span> pH. Our carbon cycle <span class="hlt">model</span> includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean <span class="hlt">climate</span> was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. <span class="hlt">Ocean</span> pH evolves monotonically from 6.6‑0.4+0.6 (2σ) at 4.0 Ga to 7.0‑0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9‑0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120012899&hterms=books&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbooks','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120012899&hterms=books&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbooks"><span>Intraseasonal Variability in the Atmosphere-<span class="hlt">Ocean</span> <span class="hlt">Climate</span> System. Second Edition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, William K. M.; Waliser, Duane E.</p> <p>2011-01-01</p> <p>Understanding and predicting the intraseasonal variability (ISV) of the <span class="hlt">ocean</span> and atmosphere is crucial to improving long-range environmental forecasts and the reliability of <span class="hlt">climate</span> change projections through <span class="hlt">climate</span> <span class="hlt">models</span>. This updated, comprehensive and authoritative second edition has a balance of observation, theory and <span class="hlt">modeling</span> and provides a single source of reference for all those interested in this important multi-faceted natural phenomenon and its relation to major short-term <span class="hlt">climatic</span> variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870026192&hterms=Parkinsons+circulation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DParkinsons%2Bcirculation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870026192&hterms=Parkinsons+circulation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DParkinsons%2Bcirculation"><span>An introduction to three-dimensional <span class="hlt">climate</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Washington, W. M.; Parkinson, C. L.</p> <p>1986-01-01</p> <p>The development and use of three-dimensional computer <span class="hlt">models</span> of the earth's <span class="hlt">climate</span> are discussed. The processes and interactions of the atmosphere, <span class="hlt">oceans</span>, and sea ice are examined. The basic theory of <span class="hlt">climate</span> simulation which includes the fundamental equations, <span class="hlt">models</span>, and numerical techniques for simulating the atmosphere, <span class="hlt">oceans</span>, and sea ice is described. Simulated wind, temperature, precipitation, <span class="hlt">ocean</span> current, and sea ice distribution data are presented and compared to observational data. The responses of the <span class="hlt">climate</span> to various environmental changes, such as variations in solar output or increases in atmospheric carbon dioxide, are <span class="hlt">modeled</span>. Future developments in <span class="hlt">climate</span> <span class="hlt">modeling</span> are considered. Information is also provided on the derivation of the energy equation, the finite difference barotropic forecast <span class="hlt">model</span>, the spectral transform technique, and the finite difference shallow water waved equation <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015726"><span>Proceedings of the <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Data Workshop</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Churgin, James (Compiler)</p> <p>1992-01-01</p> <p>The First Consultative Meeting on Responsible National Oceanographic Data Centres (RNODC's) and <span class="hlt">Climate</span> DataServices met in February 1988 and made a number of recommendations related to improving services to meet the needs of <span class="hlt">climate</span> programmes. Included in these discussions was a recommendation for a Workshop on <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Data Management. This workshop will be talking about ways to establish a Global <span class="hlt">Ocean</span> Observing System (GOOS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001BAMS...82.2357B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001BAMS...82.2357B"><span>The Community <span class="hlt">Climate</span> System <span class="hlt">Model</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blackmon, Maurice; Boville, Byron; Bryan, Frank; Dickinson, Robert; Gent, Peter; Kiehl, Jeffrey; Moritz, Richard; Randall, David; Shukla, Jagadish; Solomon, Susan; Bonan, Gordon; Doney, Scott; Fung, Inez; Hack, James; Hunke, Elizabeth; Hurrell, James; Kutzbach, John; Meehl, Jerry; Otto-Bliesner, Bette; Saravanan, R.; Schneider, Edwin K.; Sloan, Lisa; Spall, Michael; Taylor, Karl; Tribbia, Joseph; Washington, Warren</p> <p>2001-11-01</p> <p>The Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CCSM) has been created to represent the principal components of the <span class="hlt">climate</span> system and their interactions. Development and applications of the <span class="hlt">model</span> are carried out by the U.S. <span class="hlt">climate</span> research community, thus taking advantage of both wide intellectual participation and computing capabilities beyond those available to most individual U.S. institutions. This article outlines the history of the CCSM, its current capabilities, and plans for its future development and applications, with the goal of providing a summary useful to present and future users. The initial version of the CCSM included atmosphere and <span class="hlt">ocean</span> general circulation <span class="hlt">models</span>, a land surface <span class="hlt">model</span> that was grafted onto the atmosphere <span class="hlt">model</span>, a sea-ice <span class="hlt">model</span>, and a flux coupler that facilitates information exchanges among the component <span class="hlt">models</span> with their differing grids. This version of the <span class="hlt">model</span> produced a successful 300-yr simulation of the current <span class="hlt">climate</span> without artificial flux adjustments. The <span class="hlt">model</span> was then used to perform a coupled simulation in which the atmospheric CO2 concentration increased by 1% per year. In this version of the coupled <span class="hlt">model</span>, the <span class="hlt">ocean</span> salinity and deep-<span class="hlt">ocean</span> temperature slowly drifted away from observed values. A subsequent correction to the roughness length used for sea ice significantly reduced these errors. An updated version of the CCSM was used to perform three simulations of the twentieth century's <span class="hlt">climate</span>, and several pro-jections of the <span class="hlt">climate</span> of the twenty-first century. The CCSM's simulation of the tropical <span class="hlt">ocean</span> circulation has been significantly improved by reducing the background vertical diffusivity and incorporating an anisotropic horizontal viscosity tensor. The meridional resolution of the <span class="hlt">ocean</span> <span class="hlt">model</span> was also refined near the equator. These changes have resulted in a greatly improved simulation of both the Pacific equatorial undercurrent and the surface countercurrents. The interannual variability of the sea surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009046','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009046"><span><span class="hlt">Climate</span> Variability and Phytoplankton in the Pacific <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rousseaux, Cecile</p> <p>2012-01-01</p> <p>The effect of <span class="hlt">climate</span> variability on phytoplankton communities was assessed for the tropical and sub-tropical Pacific <span class="hlt">Ocean</span> between 1998 and 2005 using an established biogeochemical assimilation <span class="hlt">model</span>. The phytoplankton communities exhibited wide range of responses to <span class="hlt">climate</span> variability, from radical shifts in the Equatorial Pacific, to changes of only a couple of phytoplankton groups in the North Central Pacific, to no significant changes in the South Pacific. In the Equatorial Pacific, <span class="hlt">climate</span> variability dominated the variability of phytoplankton. Here, nitrate, chlorophyll and all but one of the 4 phytoplankton types (diatoms, cyanobacteria and coccolithophores) were strongly correlated (p<0.01) with the Multivariate El Nino Southern Oscillation Index (MEI). In the North Central Pacific, MEI and chlorophyll were significantly (p<0.01) correlated along with two of the phytoplankton groups (chlorophytes and coccolithophores). <span class="hlt">Ocean</span> biology in the South Pacific was not significantly correlated with MEI. During La Nina events, diatoms increased and expanded westward along the cold tongue (correlation with MEI, r=-0.81), while cyanobacteria concentrations decreased significantly (r=0.78). El Nino produced the reverse pattern, with cyanobacteria populations increasing while diatoms plummeted. The diverse response of phytoplankton in the different major basins of the Pacific suggests the different roles <span class="hlt">climate</span> variability can play in <span class="hlt">ocean</span> biology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020004188','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020004188"><span><span class="hlt">Modeling</span> South Pacific Ice-<span class="hlt">Ocean</span> Interactions in the Global <span class="hlt">Climate</span> System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Holland, David M.; Jenkins, Adrian; Jacobs, Stanley S.</p> <p>2001-01-01</p> <p>The objective of this project has been to improve the <span class="hlt">modeling</span> of interactions between large Antarctic ice shelves and adjacent regions of the Southern <span class="hlt">Ocean</span>. Our larger goal is to gain a better understanding of the extent to which the <span class="hlt">ocean</span> controls ice shelf attrition, thereby influencing the size and dynamics of the Antarctic Ice Sheet. Melting and freezing under ice shelves also impacts seawater properties, regional upwelling and sinking and the larger-scale <span class="hlt">ocean</span> circulation. Modifying an isopycnal coordinate general circulation <span class="hlt">model</span> for use in sub-ice shelf cavities, we found that the abrupt change in water column thickness at an ice shelf front does not form a strong barrier to buoyancy-driven circulation across the front. Outflow along the ice shelf base, driven by melting of the thickest ice, is balanced by deep inflow. Substantial effort was focused on the Filchner-Ronne cavity, where other <span class="hlt">models</span> have been applied and time-series records are available from instruments suspended beneath the ice. A <span class="hlt">model</span> comparison indicated that observed changes in the production of High Salinity Shelf Water could have a major impact on circulation within the cavity. This water propagates into the cavity with an asymmetric seasonal signal that has similar phasing and shape in the <span class="hlt">model</span> and observations, and can be related to winter production at the sea surface. Even remote parts of the sub-ice shelf cavity are impacted by external forcing on sub-annual time scales. This shows that cavity circulations and products, and therefore cavity shape, will respond to interannual variability in sea ice production and longer-term <span class="hlt">climate</span> change. The isopycnal <span class="hlt">model</span> gives generally lower net melt rates than have been obtained from other <span class="hlt">models</span> and oceanographic data, perhaps due to its boundary layer formulation, or the lack of tidal forcing. Work continues on a manuscript describing the Ross cavity results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.P51A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.P51A..08G"><span>Seeking a Role for the <span class="hlt">Ocean</span> and <span class="hlt">Ocean</span> Scientists in the Future of International <span class="hlt">Climate</span> Negotiations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallo, N.; Eddebbar, Y.; Le, J. T.; Netburn, A. N.; Niles, J. O.; Sato, K.; Wilson, S.; Levin, L. A.</p> <p>2016-02-01</p> <p>The <span class="hlt">oceans</span> cover 71% of the world and are essential to the <span class="hlt">climate</span> regulation of the planet, but they are severely underrepresented in international <span class="hlt">climate</span> negotiations. While marine ecosystems were mentioned in the preamble to the United Nations Framework Convention on <span class="hlt">Climate</span> Change (UNFCCC), they have since been left out of the text of the Kyoto Protocol and the Paris Treaty, and <span class="hlt">ocean</span>-focused events are lacking at UNFCCC meetings. However, marine ecosystems sustain severe impacts from <span class="hlt">climate</span> change including warming, acidification, and deoxygenation, and these changes have economic implications for <span class="hlt">ocean</span>-dependent nations including on tourism, fisheries sustainability, shoreline protection, and human livelihood. <span class="hlt">Ocean</span> scientists from the Scripps Institution of Oceanography and members of <span class="hlt">Ocean</span> Scientists for Informed Policy have partnered with the newly-formed <span class="hlt">Ocean</span> and <span class="hlt">Climate</span> Platform to raise <span class="hlt">ocean</span> issues at the UNFCCC meeting in Paris through both official side event presentations within the meeting venue and offsite events for the public. This study focuses on how the role and recognition of the <span class="hlt">ocean</span> in the UNFCCC negotiations has evolved from COP19 (2013) to COP21 (2015), what may be expected for the role of the <span class="hlt">ocean</span> in international <span class="hlt">climate</span> negotiations beyond the Paris Agreement, and addresses what role <span class="hlt">ocean</span> scientists can play in this conversation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P51A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P51A..08G"><span>Seeking a Role for the <span class="hlt">Ocean</span> and <span class="hlt">Ocean</span> Scientists in the Future of International <span class="hlt">Climate</span> Negotiations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallo, N.; Eddebbar, Y.; Le, J. T.; Netburn, A. N.; Niles, J. O.; Sato, K.; Wilson, S.; Levin, L. A.</p> <p>2016-12-01</p> <p>The <span class="hlt">oceans</span> cover 71% of the world and are essential to the <span class="hlt">climate</span> regulation of the planet, but they are severely underrepresented in international <span class="hlt">climate</span> negotiations. While marine ecosystems were mentioned in the preamble to the United Nations Framework Convention on <span class="hlt">Climate</span> Change (UNFCCC), they have since been left out of the text of the Kyoto Protocol and the Paris Treaty, and <span class="hlt">ocean</span>-focused events are lacking at UNFCCC meetings. However, marine ecosystems sustain severe impacts from <span class="hlt">climate</span> change including warming, acidification, and deoxygenation, and these changes have economic implications for <span class="hlt">ocean</span>-dependent nations including on tourism, fisheries sustainability, shoreline protection, and human livelihood. <span class="hlt">Ocean</span> scientists from the Scripps Institution of Oceanography and members of <span class="hlt">Ocean</span> Scientists for Informed Policy have partnered with the newly-formed <span class="hlt">Ocean</span> and <span class="hlt">Climate</span> Platform to raise <span class="hlt">ocean</span> issues at the UNFCCC meeting in Paris through both official side event presentations within the meeting venue and offsite events for the public. This study focuses on how the role and recognition of the <span class="hlt">ocean</span> in the UNFCCC negotiations has evolved from COP19 (2013) to COP21 (2015), what may be expected for the role of the <span class="hlt">ocean</span> in international <span class="hlt">climate</span> negotiations beyond the Paris Agreement, and addresses what role <span class="hlt">ocean</span> scientists can play in this conversation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://farallones.noaa.gov/manage/climate/pdf/GFNMS-Indicators-Monitoring-Plan-FINAL.pdf','USGSPUBS'); return false;" href="http://farallones.noaa.gov/manage/climate/pdf/GFNMS-Indicators-Monitoring-Plan-FINAL.pdf"><span><span class="hlt">Ocean</span> <span class="hlt">climate</span> indicators: A monitoring inventory and plan for tracking <span class="hlt">climate</span> change in the north-central California coast and <span class="hlt">ocean</span> region</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Duncan, Benet; Higgason, Kelley; Suchanek, Tom; Largier, John; Stachowicz, Jay; Allen, Sarah; Bograd, Steven; Breen, R.; Gellerman, Holly; Hill, Tessa; Jahncke, Jaime; Johnson, Rebecca L.; Lonhart, Steve I.; Morgan, Steven; Wilkerson, Frances; Roletto, Jan</p> <p>2013-01-01</p> <p>The impacts of <span class="hlt">climate</span> change, defined as increasing atmospheric and <span class="hlt">oceanic</span> carbon dioxide and associated increases in average global temperature and <span class="hlt">oceanic</span> acidity, have been observed both globally and on regional scales, such as in the North-central California coast and <span class="hlt">ocean</span>, a region that extends from Point Arena to Point Año Nuevo and includes the Pacific coastline of the San Francisco Bay Area. Because of the high economic and ecological value of the region’s marine environment, the Gulf of the Farallones National Marine Sanctuary (GFNMS) and other agencies and organizations have recognized the need to evaluate and plan for <span class="hlt">climate</span> change impacts. <span class="hlt">Climate</span> change indicators can be developed on global, regional, and site-specific spatial scales, and they provide information about the presence and potential impacts of <span class="hlt">climate</span> change. While indicators exist for the nation and for the state of California as a whole, no system of <span class="hlt">ocean</span> <span class="hlt">climate</span> indicators exist that specifically consider the unique characteristics of the California coast and <span class="hlt">ocean</span> region. To that end, GFNMS collaborated with over 50 regional, federal, and state natural resource managers, research scientists, and other partners to develop a set of 2 <span class="hlt">ocean</span> <span class="hlt">climate</span> indicators specific to this region. A smaller working group of 13 regional partners developed monitoring goals, objectives, strategies, and activities for the indicators and recommended selected species for biological indicators, resulting in the <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Indicators Monitoring Inventory and Plan. The working group considered current knowledge of ongoing monitoring, feasibility of monitoring, costs, and logistics in selecting monitoring activities and selected species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GBioC..29..744R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GBioC..29..744R"><span>Multicentury changes in <span class="hlt">ocean</span> and land contributions to the <span class="hlt">climate</span>-carbon feedback</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Randerson, J. T.; Lindsay, K.; Munoz, E.; Fu, W.; Moore, J. K.; Hoffman, F. M.; Mahowald, N. M.; Doney, S. C.</p> <p>2015-06-01</p> <p>Improved constraints on carbon cycle responses to <span class="hlt">climate</span> change are needed to inform mitigation policy, yet our understanding of how these responses may evolve after 2100 remains highly uncertain. Using the Community Earth System <span class="hlt">Model</span> (v1.0), we quantified <span class="hlt">climate</span>-carbon feedbacks from 1850 to 2300 for the Representative Concentration Pathway 8.5 and its extension. In three simulations, land and <span class="hlt">ocean</span> biogeochemical processes experienced the same trajectory of increasing atmospheric CO2. Each simulation had a different degree of radiative coupling for CO2 and other greenhouse gases and aerosols, enabling diagnosis of feedbacks. In a fully coupled simulation, global mean surface air temperature increased by 9.3 K from 1850 to 2300, with 4.4 K of this warming occurring after 2100. Excluding CO2, warming from other greenhouse gases and aerosols was 1.6 K by 2300, near a 2 K target needed to avoid dangerous anthropogenic interference with the <span class="hlt">climate</span> system. <span class="hlt">Ocean</span> contributions to the <span class="hlt">climate</span>-carbon feedback increased considerably over time and exceeded contributions from land after 2100. The sensitivity of <span class="hlt">ocean</span> carbon to <span class="hlt">climate</span> change was found to be proportional to changes in <span class="hlt">ocean</span> heat content, as a consequence of this heat modifying transport pathways for anthropogenic CO2 inflow and solubility of dissolved inorganic carbon. By 2300, <span class="hlt">climate</span> change reduced cumulative <span class="hlt">ocean</span> uptake by 330 Pg C, from 1410 Pg C to 1080 Pg C. Land fluxes similarly diverged over time, with <span class="hlt">climate</span> change reducing stocks by 232 Pg C. Regional influence of <span class="hlt">climate</span> change on carbon stocks was largest in the North Atlantic <span class="hlt">Ocean</span> and tropical forests of South America. Our analysis suggests that after 2100, <span class="hlt">oceans</span> may become as important as terrestrial ecosystems in regulating the magnitude of the <span class="hlt">climate</span>-carbon feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1265616-multicentury-changes-ocean-land-contributions-climate-carbon-feedback','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1265616-multicentury-changes-ocean-land-contributions-climate-carbon-feedback"><span>Multicentury changes in <span class="hlt">ocean</span> and land contributions to the <span class="hlt">climate</span>-carbon feedback</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Randerson, J. T.; Lindsay, K.; Munoz, E.</p> <p></p> <p>Improved constraints on carbon cycle responses to <span class="hlt">climate</span> change are needed to inform mitigation policy, yet our understanding of how these responses may evolve after 2100 remains highly uncertain. Using the Community Earth System <span class="hlt">Model</span> (v1.0), we quantified <span class="hlt">climate</span>-carbon feedbacks from 1850 to 2300 for the Representative Concentration Pathway 8.5 and its extension. In three simulations, land and <span class="hlt">ocean</span> biogeochemical processes experienced the same trajectory of increasing atmospheric CO 2. Each simulation had a different degree of radiative coupling for CO 2 and other greenhouse gases and aerosols, enabling diagnosis of feedbacks. In a fully coupled simulation, global mean surfacemore » air temperature increased by 9.3 K from 1850 to 2300, with 4.4 K of this warming occurring after 2100. Excluding CO 2, warming from other greenhouse gases and aerosols was 1.6 K by 2300, near a 2 K target needed to avoid dangerous anthropogenic interference with the <span class="hlt">climate</span> system. <span class="hlt">Ocean</span> contributions to the <span class="hlt">climate</span>-carbon feedback increased considerably over time and exceeded contributions from land after 2100. The sensitivity of <span class="hlt">ocean</span> carbon to <span class="hlt">climate</span> change was found to be proportional to changes in <span class="hlt">ocean</span> heat content, as a consequence of this heat modifying transport pathways for anthropogenic CO 2 inflow and solubility of dissolved inorganic carbon. By 2300, <span class="hlt">climate</span> change reduced cumulative <span class="hlt">ocean</span> uptake by 330 Pg C, from 1410 Pg C to 1080 Pg C. Land fluxes similarly diverged over time, with <span class="hlt">climate</span> change reducing stocks by 232 Pg C. Regional influence of <span class="hlt">climate</span> change on carbon stocks was largest in the North Atlantic <span class="hlt">Ocean</span> and tropical forests of South America. Our analysis suggests that after 2100, <span class="hlt">oceans</span> may become as important as terrestrial ecosystems in regulating the magnitude of the <span class="hlt">climate</span>-carbon feedback.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS52A..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS52A..01W"><span>Detecting anthropogenic <span class="hlt">climate</span> forcing in the <span class="hlt">ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wijffels, S. A.</p> <p>2016-12-01</p> <p>Owing to its immense heat capacity, the global <span class="hlt">ocean</span> is the fly-wheel of the <span class="hlt">climate</span> system, absorbing, redistributing and storing heat on long timescales and over great distances. Of the extra heat trapped in the Earth System due to rising greenhouse gases, over 90% is being stored in the global <span class="hlt">oceans</span>. Tracking this warming has been challenging due to past changes in the coverage and technology used in past <span class="hlt">ocean</span> observations. Here, I'll review progress in estimating past warming rates and patterns. The warming of Earth's surface is also driving changes in the global hydrological cycle, which also intimately involves the <span class="hlt">oceans</span>. Global <span class="hlt">ocean</span> salinity changes reveal another footprint of a warming Earth. Some simple <span class="hlt">model</span> runs that give insight into observed subsurface changes will also be described, along with an update on current warming rates and patterns as tracked by the global Argo programme. The prospects for the next advances in broadscale <span class="hlt">ocean</span> monitoring will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.A61C0088K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.A61C0088K"><span>Development of a High-Resolution <span class="hlt">Climate</span> <span class="hlt">Model</span> for Future <span class="hlt">Climate</span> Change Projection on the Earth Simulator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kanzawa, H.; Emori, S.; Nishimura, T.; Suzuki, T.; Inoue, T.; Hasumi, H.; Saito, F.; Abe-Ouchi, A.; Kimoto, M.; Sumi, A.</p> <p>2002-12-01</p> <p>The fastest supercomputer of the world, the Earth Simulator (total peak performance 40TFLOPS) has recently been available for <span class="hlt">climate</span> researches in Yokohama, Japan. We are planning to conduct a series of future <span class="hlt">climate</span> change projection experiments on the Earth Simulator with a high-resolution coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">climate</span> <span class="hlt">model</span>. The main scientific aims for the experiments are to investigate 1) the change in global <span class="hlt">ocean</span> circulation with an eddy-permitting <span class="hlt">ocean</span> <span class="hlt">model</span>, 2) the regional details of the <span class="hlt">climate</span> change including Asian monsoon rainfall pattern, tropical cyclones and so on, and 3) the change in natural <span class="hlt">climate</span> variability with a high-resolution <span class="hlt">model</span> of the coupled <span class="hlt">ocean</span>-atmosphere system. To meet these aims, an atmospheric GCM, CCSR/NIES AGCM, with T106(~1.1o) horizontal resolution and 56 vertical layers is to be coupled with an <span class="hlt">oceanic</span> GCM, COCO, with ~ 0.28ox 0.19o horizontal resolution and 48 vertical layers. This coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">climate</span> <span class="hlt">model</span>, named MIROC, also includes a land-surface <span class="hlt">model</span>, a dynamic-thermodynamic seaice <span class="hlt">model</span>, and a river routing <span class="hlt">model</span>. The poles of the <span class="hlt">oceanic</span> <span class="hlt">model</span> grid system are rotated from the geographic poles so that they are placed in Greenland and Antarctic land masses to avoild the singularity of the grid system. Each of the atmospheric and the <span class="hlt">oceanic</span> parts of the <span class="hlt">model</span> is parallelized with the Message Passing Interface (MPI) technique. The coupling of the two is to be done with a Multi Program Multi Data (MPMD) fashion. A 100-<span class="hlt">model</span>-year integration will be possible in one actual month with 720 vector processors (which is only 14% of the full resources of the Earth Simulator).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A33B0217T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A33B0217T"><span><span class="hlt">Ocean</span> Circulation-Cloud Interactions Reduce the Pace of Transient <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trossman, D.; Palter, J. B.; Merlis, T. M.; Huang, Y.; Xia, Y.</p> <p>2016-12-01</p> <p>We argue that a substantial fraction of the uncertainty in the cloud radiative feedback during transient <span class="hlt">climate</span> change may be due to uncertainty in the <span class="hlt">ocean</span> circulation perturbation. A suite of <span class="hlt">climate</span> <span class="hlt">model</span> simulations in which the <span class="hlt">ocean</span> circulation, the cloud radiative feedback, or a combination of both are held fixed while CO2 doubles, shows that changes in the <span class="hlt">ocean</span> circulation reduce the amount of transient global warming caused by the radiative cloud feedback. Specifically, a slowdown in the Atlantic Meridional Overturning Circulation (AMOC) helps to maintain low cloud cover in the Northern Hemisphere extratropics. We propose that the AMOC decline increases the meridional SST gradient, strengthening the storm track, its attendant clouds and the amount of shortwave radiation they reflect back to space. If the results of our <span class="hlt">model</span> were to scale proportionately in the CMIP5 <span class="hlt">models</span>, whose AMOC decline ranges from 15 to 60% under RCP8.5, then as much as 70% of the intermodel spread in the cloud radiative feedback and 35% of the spread in the transient <span class="hlt">climate</span> response could possibly stem from the <span class="hlt">model</span> representations of AMOC decline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014BGeo...11.7291K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014BGeo...11.7291K"><span>iMarNet: an <span class="hlt">ocean</span> biogeochemistry <span class="hlt">model</span> intercomparison project within a common physical <span class="hlt">ocean</span> <span class="hlt">modelling</span> framework</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwiatkowski, L.; Yool, A.; Allen, J. I.; Anderson, T. R.; Barciela, R.; Buitenhuis, E. T.; Butenschön, M.; Enright, C.; Halloran, P. R.; Le Quéré, C.; de Mora, L.; Racault, M.-F.; Sinha, B.; Totterdell, I. J.; Cox, P. M.</p> <p>2014-12-01</p> <p><span class="hlt">Ocean</span> biogeochemistry (OBGC) <span class="hlt">models</span> span a wide variety of complexities, including highly simplified nutrient-restoring schemes, nutrient-phytoplankton-zooplankton-detritus (NPZD) <span class="hlt">models</span> that crudely represent the marine biota, <span class="hlt">models</span> that represent a broader trophic structure by grouping organisms as plankton functional types (PFTs) based on their biogeochemical role (dynamic green <span class="hlt">ocean</span> <span class="hlt">models</span>) and ecosystem <span class="hlt">models</span> that group organisms by ecological function and trait. OBGC <span class="hlt">models</span> are now integral components of Earth system <span class="hlt">models</span> (ESMs), but they compete for computing resources with higher resolution dynamical setups and with other components such as atmospheric chemistry and terrestrial vegetation schemes. As such, the choice of OBGC in ESMs needs to balance <span class="hlt">model</span> complexity and realism alongside relative computing cost. Here we present an intercomparison of six OBGC <span class="hlt">models</span> that were candidates for implementation within the next UK Earth system <span class="hlt">model</span> (UKESM1). The <span class="hlt">models</span> cover a large range of biological complexity (from 7 to 57 tracers) but all include representations of at least the nitrogen, carbon, alkalinity and oxygen cycles. Each OBGC <span class="hlt">model</span> was coupled to the <span class="hlt">ocean</span> general circulation <span class="hlt">model</span> Nucleus for European <span class="hlt">Modelling</span> of the <span class="hlt">Ocean</span> (NEMO) and results from physically identical hindcast simulations were compared. <span class="hlt">Model</span> skill was evaluated for biogeochemical metrics of global-scale bulk properties using conventional statistical techniques. The computing cost of each <span class="hlt">model</span> was also measured in standardised tests run at two resource levels. No <span class="hlt">model</span> is shown to consistently outperform all other <span class="hlt">models</span> across all metrics. Nonetheless, the simpler <span class="hlt">models</span> are broadly closer to observations across a number of fields and thus offer a high-efficiency option for ESMs that prioritise high-resolution <span class="hlt">climate</span> dynamics. However, simpler <span class="hlt">models</span> provide limited insight into more complex marine biogeochemical processes and ecosystem pathways, and a parallel approach of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1166909','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1166909"><span>Improved atmosphere-<span class="hlt">ocean</span> coupled <span class="hlt">modeling</span> in the tropics for <span class="hlt">climate</span> prediction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Minghua</p> <p>2015-01-01</p> <p>We investigated the initial development of the double ITCZ in the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CCSM Version 3) in the central Pacific. Starting from a resting initial condition of the <span class="hlt">ocean</span> in January, the <span class="hlt">model</span> developed a warm bias of sea-surface temperature (SST) in the central Pacific from 5oS to 10oS in the first three months. We found this initial bias to be caused by excessive surface shortwave radiation that is also present in the standalone atmospheric <span class="hlt">model</span>. The initial bias is further amplified by biases in both surface latent heat flux and horizontal heat transport in the upper <span class="hlt">ocean</span>.more » These biases are caused by the responses of surface winds to SST bias and the thermocline structure to surface wind curls. We also showed that the warming biases in surface solar radiation and latent heat fluxes are seasonally offset by cooling biases from reduced solar radiation after the austral summer due to cloud responses and in the austral fall due to enhanced evaporation when the maximum SST is closest to the equator. The warming biases from the dynamic heat transport by <span class="hlt">ocean</span> currents however stay throughout all seasons once they are developed, which are eventually balanced by enhanced energy exchange and penetration of solar radiation below the mixed layer. Our results also showed that the equatorial cold tongue develops after the warm biases in the south central Pacific, and the overestimation of surface shortwave radiation recurs in the austral summer in each year.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16467829','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16467829"><span>Volcanoes and <span class="hlt">climate</span>: Krakatoa's signature persists in the <span class="hlt">ocean</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gleckler, P J; Wigley, T M L; Santer, B D; Gregory, J M; Achutarao, K; Taylor, K E</p> <p>2006-02-09</p> <p>We have analysed a suite of 12 state-of-the-art <span class="hlt">climate</span> <span class="hlt">models</span> and show that <span class="hlt">ocean</span> warming and sea-level rise in the twentieth century were substantially reduced by the colossal eruption in 1883 of the volcano Krakatoa in the Sunda strait, Indonesia. Volcanically induced cooling of the <span class="hlt">ocean</span> surface penetrated into deeper layers, where it persisted for decades after the event. This remarkable effect on <span class="hlt">oceanic</span> thermal structure is longer lasting than has previously been suspected and is sufficient to offset a large fraction of <span class="hlt">ocean</span> warming and sea-level rise caused by anthropogenic influences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020046681','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020046681"><span>Projected Impact of <span class="hlt">Climate</span> Change on the Energy Budget of the Arctic <span class="hlt">Ocean</span> by a Global <span class="hlt">Climate</span> <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, James R.; Russell, Gary L.; Hansen, James E. (Technical Monitor)</p> <p>2001-01-01</p> <p>The annual energy budget of the Arctic <span class="hlt">Ocean</span> is characterized by a net heat loss at the air-sea interface that is balanced by <span class="hlt">oceanic</span> heat transport into the Arctic. The energy loss at the air-sea interface is due to the combined effects of radiative, sensible, and latent heat fluxes. The inflow of heat by the <span class="hlt">ocean</span> can be divided into two components: the transport of water masses of different temperatures between the Arctic and the Atlantic and Pacific <span class="hlt">Oceans</span> and the export of sea ice, primarily through Fram Strait. Two 150-year simulations (1950-2099) of a global <span class="hlt">climate</span> <span class="hlt">model</span> are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. One is a control simulation for the present <span class="hlt">climate</span> with constant 1950 atmospheric composition, and the other is a transient experiment with observed GHGs from 1950 to 1990 and 0.5% annual compounded increases of CO2 after 1990. For the present <span class="hlt">climate</span> the <span class="hlt">model</span> agrees well with observations of radiative fluxes at the top of the atmosphere, atmospheric advective energy transport into the Arctic, and surface air temperature. It also simulates the seasonal cycle and summer increase of cloud cover and the seasonal cycle of sea-ice cover. In addition, the changes in high-latitude surface air temperature and sea-ice cover in the GHG experiment are consistent with observed changes during the last 40 and 20 years, respectively. Relative to the control, the last 50-year period of the GHG experiment indicates that even though the net annual incident solar radiation at the surface decreases by 4.6 W(per square meters) (because of greater cloud cover and increased cloud optical depth), the absorbed solar radiation increases by 2.8 W(per square meters) (because of less sea ice). Increased cloud cover and warmer air also cause increased downward thermal radiation at the surface so that the net radiation into the <span class="hlt">ocean</span> increases by 5.0 Wm-2. The annual increase in radiation into the <span class="hlt">ocean</span>, however, is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29867150','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29867150"><span>Role of subsurface <span class="hlt">ocean</span> in decadal <span class="hlt">climate</span> predictability over the South Atlantic.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morioka, Yushi; Doi, Takeshi; Storto, Andrea; Masina, Simona; Behera, Swadhin K</p> <p>2018-06-04</p> <p>Decadal <span class="hlt">climate</span> predictability in the South Atlantic is explored by performing reforecast experiments using a coupled general circulation <span class="hlt">model</span> with two initialization schemes; one is assimilated with observed sea surface temperature (SST) only, and the other is additionally assimilated with observed subsurface <span class="hlt">ocean</span> temperature and salinity. The South Atlantic is known to undergo decadal variability exhibiting a meridional dipole of SST anomalies through variations in the subtropical high and <span class="hlt">ocean</span> heat transport. Decadal reforecast experiments in which only the <span class="hlt">model</span> SST is initialized with the observation do not predict well the observed decadal SST variability in the South Atlantic, while the other experiments in which the <span class="hlt">model</span> SST and subsurface <span class="hlt">ocean</span> are initialized with the observation skillfully predict the observed decadal SST variability, particularly in the Southeast Atlantic. In-depth analysis of upper-<span class="hlt">ocean</span> heat content reveals that a significant improvement of zonal heat transport in the Southeast Atlantic leads to skillful prediction of decadal SST variability there. These results demonstrate potential roles of subsurface <span class="hlt">ocean</span> assimilation in the skillful prediction of decadal <span class="hlt">climate</span> variability over the South Atlantic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1394474-advancing-model-validated-statistical-method-decomposing-key-oceanic-drivers-regional-climate-focus-northern-tropical-african-climate-variability-community-earth-system-model-cesm','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1394474-advancing-model-validated-statistical-method-decomposing-key-oceanic-drivers-regional-climate-focus-northern-tropical-african-climate-variability-community-earth-system-model-cesm"><span>Advancing a <span class="hlt">Model</span>-Validated Statistical Method for Decomposing the Key <span class="hlt">Oceanic</span> Drivers of Regional <span class="hlt">Climate</span>: Focus on Northern and Tropical African <span class="hlt">Climate</span> Variability in the Community Earth System <span class="hlt">Model</span> (CESM)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Fuyao; Yu, Yan; Notaro, Michael</p> <p></p> <p>This study advances the practicality and stability of the traditional multivariate statistical method, generalized equilibrium feedback assessment (GEFA), for decomposing the key <span class="hlt">oceanic</span> drivers of regional atmospheric variability, especially when available data records are short. An advanced stepwise GEFA methodology is introduced, in which unimportant forcings within the forcing matrix are eliminated through stepwise selection. Method validation of stepwise GEFA is performed using the CESM, with a focused application to northern and tropical Africa (NTA). First, a statistical assessment of the atmospheric response to each primary <span class="hlt">oceanic</span> forcing is carried out by applying stepwise GEFA to a fully coupled controlmore » run. Then, a dynamical assessment of the atmospheric response to individual <span class="hlt">oceanic</span> forcings is performed through ensemble experiments by imposing sea surface temperature anomalies over focal <span class="hlt">ocean</span> basins. Finally, to quantify the reliability of stepwise GEFA, the statistical assessment is evaluated against the dynamical assessment in terms of four metrics: the percentage of grid cells with consistent response sign, the spatial correlation of atmospheric response patterns, the area-averaged seasonal cycle of response magnitude, and consistency in associated mechanisms between assessments. In CESM, tropical modes, namely El Niño–Southern Oscillation and the tropical Indian <span class="hlt">Ocean</span> Basin, tropical Indian <span class="hlt">Ocean</span> dipole, and tropical Atlantic Niño modes, are the dominant <span class="hlt">oceanic</span> controls of NTA <span class="hlt">climate</span>. In complementary studies, stepwise GEFA is validated in terms of isolating terrestrial forcings on the atmosphere, and observed <span class="hlt">oceanic</span> and terrestrial drivers of NTA <span class="hlt">climate</span> are extracted to establish an observational benchmark for subsequent coupled <span class="hlt">model</span> evaluation and development of process-based weights for regional <span class="hlt">climate</span> projections.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1394474-advancing-model-validated-statistical-method-decomposing-key-oceanic-drivers-regional-climate-focus-northern-tropical-african-climate-variability-community-earth-system-model-cesm','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1394474-advancing-model-validated-statistical-method-decomposing-key-oceanic-drivers-regional-climate-focus-northern-tropical-african-climate-variability-community-earth-system-model-cesm"><span>Advancing a <span class="hlt">Model</span>-Validated Statistical Method for Decomposing the Key <span class="hlt">Oceanic</span> Drivers of Regional <span class="hlt">Climate</span>: Focus on Northern and Tropical African <span class="hlt">Climate</span> Variability in the Community Earth System <span class="hlt">Model</span> (CESM)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Wang, Fuyao; Yu, Yan; Notaro, Michael; ...</p> <p>2017-09-27</p> <p>This study advances the practicality and stability of the traditional multivariate statistical method, generalized equilibrium feedback assessment (GEFA), for decomposing the key <span class="hlt">oceanic</span> drivers of regional atmospheric variability, especially when available data records are short. An advanced stepwise GEFA methodology is introduced, in which unimportant forcings within the forcing matrix are eliminated through stepwise selection. Method validation of stepwise GEFA is performed using the CESM, with a focused application to northern and tropical Africa (NTA). First, a statistical assessment of the atmospheric response to each primary <span class="hlt">oceanic</span> forcing is carried out by applying stepwise GEFA to a fully coupled controlmore » run. Then, a dynamical assessment of the atmospheric response to individual <span class="hlt">oceanic</span> forcings is performed through ensemble experiments by imposing sea surface temperature anomalies over focal <span class="hlt">ocean</span> basins. Finally, to quantify the reliability of stepwise GEFA, the statistical assessment is evaluated against the dynamical assessment in terms of four metrics: the percentage of grid cells with consistent response sign, the spatial correlation of atmospheric response patterns, the area-averaged seasonal cycle of response magnitude, and consistency in associated mechanisms between assessments. In CESM, tropical modes, namely El Niño–Southern Oscillation and the tropical Indian <span class="hlt">Ocean</span> Basin, tropical Indian <span class="hlt">Ocean</span> dipole, and tropical Atlantic Niño modes, are the dominant <span class="hlt">oceanic</span> controls of NTA <span class="hlt">climate</span>. In complementary studies, stepwise GEFA is validated in terms of isolating terrestrial forcings on the atmosphere, and observed <span class="hlt">oceanic</span> and terrestrial drivers of NTA <span class="hlt">climate</span> are extracted to establish an observational benchmark for subsequent coupled <span class="hlt">model</span> evaluation and development of process-based weights for regional <span class="hlt">climate</span> projections.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27396719','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27396719"><span>Solutions for ecosystem-level protection of <span class="hlt">ocean</span> systems under <span class="hlt">climate</span> change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Queirós, Ana M; Huebert, Klaus B; Keyl, Friedemann; Fernandes, Jose A; Stolte, Willem; Maar, Marie; Kay, Susan; Jones, Miranda C; Hamon, Katell G; Hendriksen, Gerrit; Vermard, Youen; Marchal, Paul; Teal, Lorna R; Somerfield, Paul J; Austen, Melanie C; Barange, Manuel; Sell, Anne F; Allen, Icarus; Peck, Myron A</p> <p>2016-12-01</p> <p>The Paris Conference of Parties (COP21) agreement renewed momentum for action against <span class="hlt">climate</span> change, creating the space for solutions for conservation of the <span class="hlt">ocean</span> addressing two of its largest threats: <span class="hlt">climate</span> change and <span class="hlt">ocean</span> acidification (CCOA). Recent arguments that <span class="hlt">ocean</span> policies disregard a mature conservation research field and that protected areas cannot address <span class="hlt">climate</span> change may be oversimplistic at this time when dynamic solutions for the management of changing <span class="hlt">oceans</span> are needed. We propose a novel approach, based on spatial meta-analysis of <span class="hlt">climate</span> impact <span class="hlt">models</span>, to improve the positioning of marine protected areas to limit CCOA impacts. We do this by estimating the vulnerability of <span class="hlt">ocean</span> ecosystems to CCOA in a spatially explicit manner and then co-mapping human activities such as the placement of renewable energy developments and the distribution of marine protected areas. We test this approach in the NE Atlantic considering also how CCOA impacts the base of the food web which supports protected species, an aspect often neglected in conservation studies. We found that, in this case, current regional conservation plans protect areas with low ecosystem-level vulnerability to CCOA, but disregard how species may redistribute to new, suitable and productive habitats. Under current plans, these areas remain open to commercial extraction and other uses. Here, and worldwide, <span class="hlt">ocean</span> conservation strategies under CCOA must recognize the long-term importance of these habitat refuges, and studies such as this one are needed to identify them. Protecting these areas creates adaptive, <span class="hlt">climate</span>-ready and ecosystem-level policy options for conservation, suitable for changing <span class="hlt">oceans</span>. © 2016 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMPP31C1759K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMPP31C1759K"><span>Mechanism of <span class="hlt">climate</span> change over South America during the LGM in coupled <span class="hlt">Ocean</span>- Atmosphere <span class="hlt">model</span> simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khodri, M.</p> <p>2006-12-01</p> <p>On a regional perspective the database of proxy information for South America during the Last Glacial Maximum (LGM) shows large and regionally extensive changes of the mean <span class="hlt">climate</span> and vegetation types over the Amazon basin. In some instances these changes were associated with decrease in the mean precipitation amount (and most probably in moist deep convection) over the Amazonian and South East Brazil monsoon regions and wetter mean conditions in present day drought-prone regions such as Northeast of Brazil (Nordeste). These changes have been interpreted as local responses to shift in the mean position and intensity of the Atlantic ITCZ due to glacial extratropical forcings or to changes in the South American Monsoons. However there are still two issues is the path to further understand the mechanism of <span class="hlt">climate</span> change over South America during the LGM. The first is incomplete knowledge in both the <span class="hlt">modeling</span> and observational communities of how the moist deep convection over the Amazonian region respond to glacial boundary condition and how this changes might interact with the meridional shift of rainfall over Nordeste and Atlantic <span class="hlt">Ocean</span>. The second is our understanding of how <span class="hlt">ocean</span>-atmosphere changes that do occur in the tropical Pacific region influence the <span class="hlt">climate</span> of the remainder of the planet and on a regional way over South America. Using PMIP-2 coupled <span class="hlt">Ocean</span>-Atmosphere simulations for LGM and comparison to paleodata we show that hydrological cycle changes over the Amazon basin might be independent of their Atlantic <span class="hlt">Ocean</span> counterpart, while teleconnections with Pacific <span class="hlt">Ocean</span> might have played a significant role in the observed changes over tropical South America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018OcMod.123...66C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018OcMod.123...66C"><span>CMIP5-based global wave <span class="hlt">climate</span> projections including the entire Arctic <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Casas-Prat, M.; Wang, X. L.; Swart, N.</p> <p>2018-03-01</p> <p>This study presents simulations of the global <span class="hlt">ocean</span> wave <span class="hlt">climate</span> corresponding to the surface winds and sea ice concentrations as simulated by five CMIP5 (Coupled <span class="hlt">Model</span> Intercomparison Project Phase 5) <span class="hlt">climate</span> <span class="hlt">models</span> for the historical (1979-2005) and RCP8.5 scenario future (2081-2100) periods. To tackle the numerical complexities associated with the inclusion of the North Pole, the WAVEWATCH III (WW3) wave <span class="hlt">model</span> was used with a customized unstructured Spherical Multi-Cell grid of ∼100 km offshore and ∼50 km along coastlines. The <span class="hlt">climate</span> <span class="hlt">model</span> simulated wind and sea ice data, and the corresponding WW3 simulated wave data, were evaluated against reanalysis and hindcast data. The results show that all the five sets of wave simulations projected lower waves in the North Atlantic, corresponding to decreased surface wind speeds there in the warmer <span class="hlt">climate</span>. The selected CMIP5 <span class="hlt">models</span> also consistently projected an increase in the surface wind speed in the Southern Hemisphere (SH) mid-high latitudes, which translates in an increase in the WW3 simulated significant wave height (Hs) there. The higher waves are accompanied with increased peak wave period and increased wave age in the East Pacific and Indian <span class="hlt">Oceans</span>, and a significant counterclockwise rotation in the mean wave direction in the Southern <span class="hlt">Oceans</span>. The latter is caused by more intense waves from the SH traveling equatorward and developing into swells. Future wave <span class="hlt">climate</span> in the Arctic <span class="hlt">Ocean</span> in summer is projected to be predominantly of mixed sea states, with the climatological mean of September maximum Hs ranging mostly 3-4 m. The new waves approaching Arctic coasts will be less fetch-limited as ice retreats since a predominantly southwards mean wave direction is projected in the surrounding seas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cpc.ncep.noaa.gov/products/GODAS/background.shtml','SCIGOVWS'); return false;" href="http://www.cpc.ncep.noaa.gov/products/GODAS/background.shtml"><span><span class="hlt">Climate</span> Prediction Center - NCEP Global <span class="hlt">Ocean</span> Data Assimilation System:</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>home page National Weather Service NWS logo - Click to go to the NWS home page <em><span class="hlt">Climate</span></em> Prediction Monthly in NetCDF Other formats Links NOAA <span class="hlt">Ocean</span> <em><span class="hlt">Climate</span></em> Observation Program (OCO) <em><span class="hlt">Climate</span></em> Test Bed About Prediction (NCEP) are a valuable community asset for monitoring different aspects of <span class="hlt">ocean</span> <em><span class="hlt">climate</span></em></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007nmoc.book.....M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007nmoc.book.....M"><span>Numerical <span class="hlt">Modeling</span> of <span class="hlt">Ocean</span> Circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Robert N.</p> <p>2007-01-01</p> <p>The <span class="hlt">modelling</span> of <span class="hlt">ocean</span> circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of <span class="hlt">climate</span> change. This book introduces the basic computational techniques necessary for all <span class="hlt">models</span> of the <span class="hlt">ocean</span> and atmosphere, and the conditions they must satisfy. It describes the workings of <span class="hlt">ocean</span> <span class="hlt">models</span>, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining <span class="hlt">ocean</span> <span class="hlt">models</span> critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of <span class="hlt">Oceanic</span> and Atmospheric Sciences at Oregon State University, this book is ideal for graduate students of oceanography, geophysics, climatology and atmospheric science, and researchers in oceanography and atmospheric science. Features examples and critical examination of <span class="hlt">ocean</span> <span class="hlt">modelling</span> and results Demonstrates the strengths and weaknesses of different approaches Includes exercises to illustrate major points and supplement mathematical and physical details</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ESD.....7..937C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ESD.....7..937C"><span>A conceptual <span class="hlt">model</span> of <span class="hlt">oceanic</span> heat transport in the Snowball Earth scenario</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Comeau, Darin; Kurtze, Douglas A.; Restrepo, Juan M.</p> <p>2016-12-01</p> <p>Geologic evidence suggests that the Earth may have been completely covered in ice in the distant past, a state known as Snowball Earth. This is still the subject of controversy, and has been the focus of <span class="hlt">modeling</span> work from low-dimensional <span class="hlt">models</span> up to state-of-the-art general circulation <span class="hlt">models</span>. In our present global <span class="hlt">climate</span>, the <span class="hlt">ocean</span> plays a large role in redistributing heat from the equatorial regions to high latitudes, and as an important part of the global heat budget, its role in the initiation a Snowball Earth, and the subsequent <span class="hlt">climate</span>, is of great interest. To better understand the role of <span class="hlt">oceanic</span> heat transport in the initiation of Snowball Earth, and the resulting global ice covered <span class="hlt">climate</span> state, the goal of this inquiry is twofold: we wish to propose the least complex <span class="hlt">model</span> that can capture the Snowball Earth scenario as well as the present-day <span class="hlt">climate</span> with partial ice cover, and we want to determine the relative importance of <span class="hlt">oceanic</span> heat transport. To do this, we develop a simple <span class="hlt">model</span>, incorporating thermohaline dynamics from traditional box <span class="hlt">ocean</span> <span class="hlt">models</span>, a radiative balance from energy balance <span class="hlt">models</span>, and the more contemporary "sea glacier" <span class="hlt">model</span> to account for viscous flow effects of extremely thick sea ice. The resulting <span class="hlt">model</span>, consisting of dynamic <span class="hlt">ocean</span> and ice components, is able to reproduce both Snowball Earth and present-day conditions through reasonable changes in forcing parameters. We find that including or neglecting <span class="hlt">oceanic</span> heat transport may lead to vastly different global <span class="hlt">climate</span> states, and also that the parameterization of under-ice heat transfer in the ice-<span class="hlt">ocean</span> coupling plays a key role in the resulting global <span class="hlt">climate</span> state, demonstrating the regulatory effect of dynamic <span class="hlt">ocean</span> heat transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.1404R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.1404R"><span>Stable "Waterbelt" <span class="hlt">climates</span> controlled by tropical <span class="hlt">ocean</span> heat transport: A nonlinear coupled <span class="hlt">climate</span> mechanism of relevance to Snowball Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rose, Brian E. J.</p> <p>2015-02-01</p> <p>Ongoing controversy about Neoproterozoic Snowball Earth events motivates a theoretical study of stability and hysteresis properties of very cold <span class="hlt">climates</span>. A coupled atmosphere-<span class="hlt">ocean</span>-sea ice general circulation <span class="hlt">model</span> (GCM) has four stable equilibria ranging from 0% to 100% ice cover, including a "Waterbelt" state with tropical sea ice. All four states are found at present-day insolation and greenhouse gas levels and with two idealized <span class="hlt">ocean</span> basin configurations. The Waterbelt is stabilized against albedo feedback by intense but narrow wind-driven <span class="hlt">ocean</span> overturning cells that deliver roughly 100 W m-2 heating to the ice edges. This requires three-way feedback between winds, <span class="hlt">ocean</span> circulation, and ice extent in which circulation is shifted equatorward, following the baroclinicity at the ice margins. The thermocline is much shallower and outcrops in the tropics. Sea ice is snow-covered everywhere and has a minuscule seasonal cycle. The Waterbelt state spans a 46 W m-2 range in solar constant, has a significant hysteresis, and permits near-freezing equatorial surface temperatures. Additional context is provided by a slab <span class="hlt">ocean</span> GCM and a diffusive energy balance <span class="hlt">model</span>, both with prescribed <span class="hlt">ocean</span> heat transport (OHT). Unlike the fully coupled <span class="hlt">model</span>, these support no more than one stable ice margin, the position of which is slaved to regions of rapid poleward decrease in OHT convergence. Wide ranges of different <span class="hlt">climates</span> (including the stable Waterbelt) are found by varying the magnitude and spatial structure of OHT in both <span class="hlt">models</span>. Some thermodynamic arguments for the sensitivity of <span class="hlt">climate</span>, and ice extent to OHT are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1816529B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1816529B"><span>Slab <span class="hlt">Ocean</span> El Niño atmospheric feedbacks in Coupled <span class="hlt">Climate</span> <span class="hlt">Models</span> and its relationship to the Recharge Oscillator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bayr, Tobias; Wengel, Christian; Latif, Mojib</p> <p>2016-04-01</p> <p>Dommenget (2010) found that El Niño-like variability, termed Slab <span class="hlt">Ocean</span> El Niño, can exist in the absence of <span class="hlt">ocean</span> dynamics and is driven by the interaction of the atmospheric surface heat fluxes and the heat content of the upper <span class="hlt">ocean</span>. Further, Dommenget et al. (2014) report the Slab <span class="hlt">Ocean</span> El Niño is not an artefact of the ECHAM5-AGCM coupled to a slab <span class="hlt">ocean</span> <span class="hlt">model</span>. In fact, atmospheric feedbacks crucial to the Slab <span class="hlt">Ocean</span> El Niño can also be found in many state-of-the-art coupled <span class="hlt">climate</span> <span class="hlt">models</span> participating in CMIP3 and CMIP5, so that ENSO in many CMIP <span class="hlt">models</span> can be understood as a mixed recharge oscillator/Slab <span class="hlt">Ocean</span> El Niño mode. Here we show further analysis of the Slab <span class="hlt">Ocean</span> El Niño atmospheric feedbacks in coupled <span class="hlt">models</span>. The BCCR_CM2.0 <span class="hlt">climate</span> <span class="hlt">model</span> from the CMIP3 data base, which has a very large equatorial cold bias, has an El Niño that is mostly driven by Slab <span class="hlt">Ocean</span> El Niño atmospheric feedbacks and is used as an example to describe Slab <span class="hlt">Ocean</span> El Niño atmospheric feedbacks in a coupled <span class="hlt">model</span>. In the BCCR_CM2.0, the ENSO-related variability in the 20°C isotherm (Z20), a measure of upper <span class="hlt">ocean</span> heat content, is decoupled from the first mode of the seasonal cycle-related variability, while the two are coupled in observations, with ENSO being phase-locked to the seasonal cycle. Further analysis of the seasonal cycle in Z20 using SODA <span class="hlt">Ocean</span> Reanalysis reveals two different regimes in the seasonal cycle along the equator: The first regime, to which ENSO is phase-locked, extends over the west and central equatorial Pacific and is driven by subsurface <span class="hlt">ocean</span> dynamics. The second regime, extending in observations only over the cold tongue region, is driven by the seasonal cycle at the sea surface and is shifted by roughly six months relative to the first regime. In a series of experiments with the Kiel <span class="hlt">Climate</span> <span class="hlt">Model</span> (KCM) with different mean states due to tuning in the convection parameters, we can show that the strength of the equatorial cold bias and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.2369R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.2369R"><span>Towards multi-resolution global <span class="hlt">climate</span> <span class="hlt">modeling</span> with ECHAM6-FESOM. Part II: <span class="hlt">climate</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rackow, T.; Goessling, H. F.; Jung, T.; Sidorenko, D.; Semmler, T.; Barbi, D.; Handorf, D.</p> <p>2018-04-01</p> <p>This study forms part II of two papers describing ECHAM6-FESOM, a newly established global <span class="hlt">climate</span> <span class="hlt">model</span> with a unique multi-resolution sea ice-<span class="hlt">ocean</span> component. While part I deals with the <span class="hlt">model</span> description and the mean <span class="hlt">climate</span> state, here we examine the internal <span class="hlt">climate</span> variability of the <span class="hlt">model</span> under constant present-day (1990) conditions. We (1) assess the internal variations in the <span class="hlt">model</span> in terms of objective variability performance indices, (2) analyze variations in global mean surface temperature and put them in context to variations in the observed record, with particular emphasis on the recent warming slowdown, (3) analyze and validate the most common atmospheric and <span class="hlt">oceanic</span> variability patterns, (4) diagnose the potential predictability of various <span class="hlt">climate</span> indices, and (5) put the multi-resolution approach to the test by comparing two setups that differ only in <span class="hlt">oceanic</span> resolution in the equatorial belt, where one <span class="hlt">ocean</span> mesh keeps the coarse 1° resolution applied in the adjacent open-<span class="hlt">ocean</span> regions and the other mesh is gradually refined to 0.25°. Objective variability performance indices show that, in the considered setups, ECHAM6-FESOM performs overall favourably compared to five well-established <span class="hlt">climate</span> <span class="hlt">models</span>. Internal variations of the global mean surface temperature in the <span class="hlt">model</span> are consistent with observed fluctuations and suggest that the recent warming slowdown can be explained as a once-in-one-hundred-years event caused by internal <span class="hlt">climate</span> variability; periods of strong cooling in the <span class="hlt">model</span> (`hiatus' analogs) are mainly associated with ENSO-related variability and to a lesser degree also to PDO shifts, with the AMO playing a minor role. Common atmospheric and <span class="hlt">oceanic</span> variability patterns are simulated largely consistent with their real counterparts. Typical deficits also found in other <span class="hlt">models</span> at similar resolutions remain, in particular too weak non-seasonal variability of SSTs over large parts of the <span class="hlt">ocean</span> and episodic periods of almost absent</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSHE44D1547S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSHE44D1547S"><span>Southern <span class="hlt">Ocean</span> vertical iron fluxes; the <span class="hlt">ocean</span> <span class="hlt">model</span> effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schourup-Kristensen, V.; Haucke, J.; Losch, M. J.; Wolf-Gladrow, D.; Voelker, C. D.</p> <p>2016-02-01</p> <p>The Southern <span class="hlt">Ocean</span> plays a key role in the <span class="hlt">climate</span> system, but commonly used large-scale <span class="hlt">ocean</span> general circulation biogeochemical <span class="hlt">models</span> give different estimates of current and future Southern <span class="hlt">Ocean</span> net primary and export production. The representation of the Southern <span class="hlt">Ocean</span> iron sources plays an important role for the <span class="hlt">modeled</span> biogeochemistry. Studies of the iron supply to the surface mixed layer have traditionally focused on the aeolian and sediment contributions, but recent work has highlighted the importance of the vertical supply from below. We have performed a <span class="hlt">model</span> study in which the biogeochemical <span class="hlt">model</span> REcoM2 was coupled to two different <span class="hlt">ocean</span> <span class="hlt">models</span>, the Finite Element Sea-ice <span class="hlt">Ocean</span> <span class="hlt">Model</span> (FESOM) and the MIT general circulation <span class="hlt">model</span> (MITgcm) and analyzed the magnitude of the iron sources to the surface mixed layer from below in the two <span class="hlt">models</span>. Our results revealed a remarkable difference in terms of mechanism and magnitude of transport. The mean iron supply from below in the Southern <span class="hlt">Ocean</span> was on average four times higher in MITgcm than in FESOM and the dominant pathway was entrainment in MITgcm, whereas diffusion dominated in FESOM. Differences in the depth and seasonal amplitude of the mixed layer between the <span class="hlt">models</span> affect on the vertical iron profile, the relative position of the base of the mixed layer and ferricline and thereby also on the iron fluxes. These differences contribute to differences in the phytoplankton composition in the two <span class="hlt">models</span>, as well as in the timing of the onset of the spring bloom. The study shows that the choice of <span class="hlt">ocean</span> <span class="hlt">model</span> has a significant impact on the iron supply to the Southern <span class="hlt">Ocean</span> mixed layer and thus on the <span class="hlt">modeled</span> carbon cycle, with possible implications for <span class="hlt">model</span> runs predicting the future carbon uptake in the region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15...64H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15...64H"><span>Southern <span class="hlt">Ocean</span> Bottom Water Characteristics in CMIP5 <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heuzé, Céline; Heywood, Karen; Stevens, David; Ridley, Jeff</p> <p>2013-04-01</p> <p>The depiction of Southern <span class="hlt">Ocean</span> deep water properties and formation processes in <span class="hlt">climate</span> <span class="hlt">models</span> is an indicator of their capability to simulate future <span class="hlt">climate</span>, heat and carbon uptake, and sea level rise. Southern <span class="hlt">Ocean</span> potential temperature and density averaged over 1986-2005 from fifteen CMIP5 <span class="hlt">climate</span> <span class="hlt">models</span> are compared with an observed climatology, focusing on bottom water properties. The mean bottom properties are reasonably accurate for half of the <span class="hlt">models</span>, but the other half may not yet have approached an equilibrium state. Eleven <span class="hlt">models</span> create dense water on the Antarctic shelf, but it does not spill off and propagate northwards, alternatively mixing rapidly with less dense water. Instead most <span class="hlt">models</span> create deep water by open <span class="hlt">ocean</span> deep convection. <span class="hlt">Models</span> with large deep convection areas are those with a strong seasonal cycle in sea ice. The most accurate bottom properties occur in <span class="hlt">models</span> hosting deep convection in the Weddell and Ross gyres.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMOS21A1361J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMOS21A1361J"><span>Isolating Tracers of Phytoplankton with Allometric Zooplankton (TOPAZ) from Modular <span class="hlt">Ocean</span> <span class="hlt">Model</span> (MOM5) to Couple it with a Global <span class="hlt">Ocean</span> <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, H. C.; Moon, B. K.; Wie, J.; Park, H. S.; Kim, K. Y.; Lee, J.; Byun, Y. H.</p> <p>2017-12-01</p> <p>This research is motivated by a need to develop a new coupled <span class="hlt">ocean</span>-biogeochemistry <span class="hlt">model</span>, a key tool for <span class="hlt">climate</span> projections. The Modular <span class="hlt">Ocean</span> <span class="hlt">Model</span> (MOM5) is a global <span class="hlt">ocean</span>/ice <span class="hlt">model</span> developed by the Geophysical Fluid Dynamics Laboratory (GFDL) in the US, and it incorporates Tracers of Phytoplankton with Allometric Zooplankton (TOPAZ), which simulates the marine biota associated with carbon cycles. We isolated TOPAZ from MOM5 into a stand-alone version (TOPAZ-SA), and had it receive initial data and <span class="hlt">ocean</span> physical fields required. Then, its reliability was verified by comparing the simulation results from the TOPAZ-SA with the MOM5/TOPAZ. This stand-alone version of TOPAZ is to be coupled to the Nucleus for European <span class="hlt">Modelling</span> of the <span class="hlt">Ocean</span> (NEMO). Here we present the preliminary results. Acknowledgements This research was supported by the project "Research and Development for KMA Weather, <span class="hlt">Climate</span>, and Earth system Services" (NIMS-2016-3100) of the National Institute of Meteorological Sciences/Korea Meteorological Administration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A43F3331F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A43F3331F"><span><span class="hlt">Climate</span> Change Response of <span class="hlt">Ocean</span> Net Primary Production (NPP) and Export Production (EP) Regulated by Stratification Increases in The CMIP5 <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, W.; Randerson, J. T.; Moore, J. K.</p> <p>2014-12-01</p> <p><span class="hlt">Ocean</span> warming due to rising atmospheric CO2 has increasing impacts on <span class="hlt">ocean</span> ecosystems by modifying the ecophysiology and distribution of marine organisms, and by altering <span class="hlt">ocean</span> circulation and stratification. We explore <span class="hlt">ocean</span> NPP and EP changes at the global scale with simulations performed in the framework of the fifth Coupled <span class="hlt">Model</span> Inter-comparison Project (CMIP5). Global NPP and EP are reduced considerably by the end of the century for the representative concentration pathway (RCP) 8.5 scenario, although <span class="hlt">models</span> differ in their significantly in their direct temperature impacts on production and remineralization. The Earth system <span class="hlt">models</span> used here project similar NPP trends albeit the magnitudes vary substantially. In general, projected changes in the 2090s for NPP range between -2.3 to -16.2% while export production reach -7 to -18% relative to 1990s. This is accompanied by increased stratification by 17-30%. Results indicate that globally reduced NPP is closely related to increased <span class="hlt">ocean</span> stratification (R2=0.78). This is especially the case for global export production, that seems to be mostly controlled by the increased stratification (R2=0.95). We also identify phytoplankton community impacts on these patterns, that vary across the <span class="hlt">models</span>. The negative response of NPP to <span class="hlt">climate</span> change may be through bottom-up control, leading to a reduced capacity of <span class="hlt">oceans</span> to regulate <span class="hlt">climate</span> through the biological carbon pump. There are large disagreements among the CMIP5 <span class="hlt">models</span> in terms of simulated nutrient and oxygen concentrations for the 1990s, and their trends over time with <span class="hlt">climate</span> change. In addition, potentially important marine biogeochemical feedbacks on the <span class="hlt">climate</span> system were not well represented in the CMIP5 <span class="hlt">models</span>, including important feedbacks with aerosol deposition and the marine iron cycle, and feedbacks involving the oxygen minimum zones and the marine nitrogen cycle. Thus, these substantial reductions in primary productivity and export production over</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24248352','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24248352"><span>Spontaneous abrupt <span class="hlt">climate</span> change due to an atmospheric blocking-sea-ice-<span class="hlt">ocean</span> feedback in an unforced <span class="hlt">climate</span> <span class="hlt">model</span> simulation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drijfhout, Sybren; Gleeson, Emily; Dijkstra, Henk A; Livina, Valerie</p> <p>2013-12-03</p> <p>Abrupt <span class="hlt">climate</span> change is abundant in geological records, but <span class="hlt">climate</span> <span class="hlt">models</span> rarely have been able to simulate such events in response to realistic forcing. Here we report on a spontaneous abrupt cooling event, lasting for more than a century, with a temperature anomaly similar to that of the Little Ice Age. The event was simulated in the preindustrial control run of a high-resolution <span class="hlt">climate</span> <span class="hlt">model</span>, without imposing external perturbations. Initial cooling started with a period of enhanced atmospheric blocking over the eastern subpolar gyre. In response, a southward progression of the sea-ice margin occurred, and the sea-level pressure anomaly was locked to the sea-ice margin through thermal forcing. The cold-core high steered more cold air to the area, reinforcing the sea-ice concentration anomaly east of Greenland. The sea-ice surplus was carried southward by <span class="hlt">ocean</span> currents around the tip of Greenland. South of 70 °N, sea ice already started melting and the associated freshwater anomaly was carried to the Labrador Sea, shutting off deep convection. There, surface waters were exposed longer to atmospheric cooling and sea surface temperature dropped, causing an even larger thermally forced high above the Labrador Sea. In consequence, east of Greenland, anomalous winds changed from north to south, terminating the event with similar abruptness to its onset. Our results imply that only <span class="hlt">climate</span> <span class="hlt">models</span> that possess sufficient resolution to correctly represent atmospheric blocking, in combination with a sensitive sea-ice <span class="hlt">model</span>, are able to simulate this kind of abrupt <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3856815','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3856815"><span>Spontaneous abrupt <span class="hlt">climate</span> change due to an atmospheric blocking–sea-ice–<span class="hlt">ocean</span> feedback in an unforced <span class="hlt">climate</span> <span class="hlt">model</span> simulation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Drijfhout, Sybren; Gleeson, Emily; Dijkstra, Henk A.; Livina, Valerie</p> <p>2013-01-01</p> <p>Abrupt <span class="hlt">climate</span> change is abundant in geological records, but <span class="hlt">climate</span> <span class="hlt">models</span> rarely have been able to simulate such events in response to realistic forcing. Here we report on a spontaneous abrupt cooling event, lasting for more than a century, with a temperature anomaly similar to that of the Little Ice Age. The event was simulated in the preindustrial control run of a high-resolution <span class="hlt">climate</span> <span class="hlt">model</span>, without imposing external perturbations. Initial cooling started with a period of enhanced atmospheric blocking over the eastern subpolar gyre. In response, a southward progression of the sea-ice margin occurred, and the sea-level pressure anomaly was locked to the sea-ice margin through thermal forcing. The cold-core high steered more cold air to the area, reinforcing the sea-ice concentration anomaly east of Greenland. The sea-ice surplus was carried southward by <span class="hlt">ocean</span> currents around the tip of Greenland. South of 70°N, sea ice already started melting and the associated freshwater anomaly was carried to the Labrador Sea, shutting off deep convection. There, surface waters were exposed longer to atmospheric cooling and sea surface temperature dropped, causing an even larger thermally forced high above the Labrador Sea. In consequence, east of Greenland, anomalous winds changed from north to south, terminating the event with similar abruptness to its onset. Our results imply that only <span class="hlt">climate</span> <span class="hlt">models</span> that possess sufficient resolution to correctly represent atmospheric blocking, in combination with a sensitive sea-ice <span class="hlt">model</span>, are able to simulate this kind of abrupt <span class="hlt">climate</span> change. PMID:24248352</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28978724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28978724"><span>The growth of finfish in global open-<span class="hlt">ocean</span> aquaculture under <span class="hlt">climate</span> change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klinger, Dane H; Levin, Simon A; Watson, James R</p> <p>2017-10-11</p> <p>Aquaculture production is projected to expand from land-based operations to the open <span class="hlt">ocean</span> as demand for seafood grows and competition increases for inputs to land-based aquaculture, such as freshwater and suitable land. In contrast to land-based production, open-<span class="hlt">ocean</span> aquaculture is constrained by oceanographic factors, such as current speeds and seawater temperature, which are dynamic in time and space, and cannot easily be controlled. As such, the potential for offshore aquaculture to increase seafood production is tied to the physical state of the <span class="hlt">oceans</span>. We employ a novel spatial <span class="hlt">model</span> to estimate the potential of open-<span class="hlt">ocean</span> finfish aquaculture globally, given physical, biological and technological constraints. Finfish growth potential for three common aquaculture species representing different thermal guilds-Atlantic salmon ( Salmo salar ), gilthead seabream ( Sparus aurata ) and cobia ( Rachycentron canadum )-is compared across species and regions and with <span class="hlt">climate</span> change, based on outputs of a high-resolution global <span class="hlt">climate</span> <span class="hlt">model</span>. Globally, there are ample areas that are physically suitable for fish growth and potential expansion of the nascent aquaculture industry. The effects of <span class="hlt">climate</span> change are heterogeneous across species and regions, but areas with existing aquaculture industries are likely to see increases in growth rates. In areas where <span class="hlt">climate</span> change results in reduced growth rates, adaptation measures, such as selective breeding, can probably offset potential production losses. © 2017 The Author(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.6106G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.6106G"><span><span class="hlt">Ocean</span> Hydrodynamics Numerical <span class="hlt">Model</span> in Curvilinear Coordinates for Simulating Circulation of the Global <span class="hlt">Ocean</span> and its Separate Basins.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gusev, Anatoly; Diansky, Nikolay; Zalesny, Vladimir</p> <p>2010-05-01</p> <p>The original program complex is proposed for the <span class="hlt">ocean</span> circulation sigma-<span class="hlt">model</span>, developed in the Institute of Numerical Mathematics (INM), Russian Academy of Sciences (RAS). The complex can be used in various curvilinear orthogonal coordinate systems. In addition to <span class="hlt">ocean</span> circulation <span class="hlt">model</span>, the complex contains a sea ice dynamics and thermodynamics <span class="hlt">model</span>, as well as the original system of the atmospheric forcing implementation on the basis of both prescribed meteodata and atmospheric <span class="hlt">model</span> results. This complex can be used as the <span class="hlt">oceanic</span> block of Earth <span class="hlt">climate</span> <span class="hlt">model</span> as well as for solving the scientific and practical problems concerning the World <span class="hlt">ocean</span> and its separate <span class="hlt">oceans</span> and seas. The developed program complex can be effectively used on parallel shared memory computational systems and on contemporary personal computers. On the base of the complex proposed the <span class="hlt">ocean</span> general circulation <span class="hlt">model</span> (OGCM) was developed. The <span class="hlt">model</span> is realized in the curvilinear orthogonal coordinate system obtained by the conformal transformation of the standard geographical grid that allowed us to locate the system singularities outside the integration domain. The horizontal resolution of the OGCM is 1 degree on longitude, 0.5 degree on latitude, and it has 40 non-uniform sigma-levels in depth. The <span class="hlt">model</span> was integrated for 100 years starting from the Levitus January climatology using the realistic atmospheric annual cycle calculated on the base of CORE datasets. The experimental results showed us that the <span class="hlt">model</span> adequately reproduces the basic characteristics of large-scale World <span class="hlt">Ocean</span> dynamics, that is in good agreement with both observational data and results of the best <span class="hlt">climatic</span> OGCMs. This OGCM is used as the <span class="hlt">oceanic</span> component of the new version of <span class="hlt">climatic</span> system <span class="hlt">model</span> (CSM) developed in INM RAS. The latter is now ready for carrying out the new numerical experiments on <span class="hlt">climate</span> and its change <span class="hlt">modelling</span> according to IPCC (Intergovernmental Panel on <span class="hlt">Climate</span> Change) scenarios in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070023935&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070023935&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges"><span>NASA Supercomputer Improves Prospects for <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Menemenlis, D.; Hill, C.; Adcroft, A.; Campin, J. -M.; Cheng, B.; Ciotti, B.; Fukumori, I.; Heimbach, P.; Henze, C.; Kohl, A.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20070023935'); toggleEditAbsImage('author_20070023935_show'); toggleEditAbsImage('author_20070023935_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20070023935_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20070023935_hide"></p> <p>2005-01-01</p> <p>Estimates of <span class="hlt">ocean</span> circulation constrained by in situ and remotely sensed observations have become routinely available during the past five years, and they are being applied to myriad scientific and operational problems [Stammer et al.,2002]. Under the Global <span class="hlt">Ocean</span> Data Assimilation Experiment (GODAE), several regional and global estimates have evolved for applications in <span class="hlt">climate</span> research, seasonal forecasting, naval operations, marine safety, fisheries,the offshore oil industry, coastal management, and other areas. This article reports on recent progress by one effort, the consortium for Estimating the Circulation and <span class="hlt">Climate</span> of the <span class="hlt">Ocean</span> (ECCO), toward a next-generation synthesis of <span class="hlt">ocean</span> and sea-ice data that is global, that covers the full <span class="hlt">ocean</span> depth, and that permits eddies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018OcMod.121...19M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018OcMod.121...19M"><span>Estimating the numerical diapycnal mixing in an eddy-permitting <span class="hlt">ocean</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Megann, Alex</p> <p>2018-01-01</p> <p>Constant-depth (or "z-coordinate") <span class="hlt">ocean</span> <span class="hlt">models</span> such as MOM4 and NEMO have become the de facto workhorse in <span class="hlt">climate</span> applications, having attained a mature stage in their development and are well understood. A generic shortcoming of this <span class="hlt">model</span> type, however, is a tendency for the advection scheme to produce unphysical numerical diapycnal mixing, which in some cases may exceed the explicitly parameterised mixing based on observed physical processes, and this is likely to have effects on the long-timescale evolution of the simulated <span class="hlt">climate</span> system. Despite this, few quantitative estimates have been made of the typical magnitude of the effective diapycnal diffusivity due to numerical mixing in these <span class="hlt">models</span>. GO5.0 is a recent <span class="hlt">ocean</span> <span class="hlt">model</span> configuration developed jointly by the UK Met Office and the National Oceanography Centre. It forms the <span class="hlt">ocean</span> component of the GC2 <span class="hlt">climate</span> <span class="hlt">model</span>, and is closely related to the <span class="hlt">ocean</span> component of the UKESM1 Earth System <span class="hlt">Model</span>, the UK's contribution to the CMIP6 <span class="hlt">model</span> intercomparison. GO5.0 uses version 3.4 of the NEMO <span class="hlt">model</span>, on the ORCA025 global tripolar grid. An approach to quantifying the numerical diapycnal mixing in this <span class="hlt">model</span>, based on the isopycnal watermass analysis of Lee et al. (2002), is described, and the estimates thereby obtained of the effective diapycnal diffusivity in GO5.0 are compared with the values of the explicit diffusivity used by the <span class="hlt">model</span>. It is shown that the effective mixing in this <span class="hlt">model</span> configuration is up to an order of magnitude higher than the explicit mixing in much of the <span class="hlt">ocean</span> interior, implying that mixing in the <span class="hlt">model</span> below the mixed layer is largely dominated by numerical mixing. This is likely to have adverse consequences for the representation of heat uptake in <span class="hlt">climate</span> <span class="hlt">models</span> intended for decadal <span class="hlt">climate</span> projections, and in particular is highly relevant to the interpretation of the CMIP6 class of <span class="hlt">climate</span> <span class="hlt">models</span>, many of which use constant-depth <span class="hlt">ocean</span> <span class="hlt">models</span> at ¼° resolution</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1420443-active-role-ocean-temporal-evolution-climate-sensitivity','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1420443-active-role-ocean-temporal-evolution-climate-sensitivity"><span>The Active Role of the <span class="hlt">Ocean</span> in the Temporal Evolution of <span class="hlt">Climate</span> Sensitivity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai; ...</p> <p>2017-11-30</p> <p>Here, the temporal evolution of the effective <span class="hlt">climate</span> sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and <span class="hlt">ocean</span> heat uptake (OHU), which in turn have been attributed to <span class="hlt">ocean</span> circulation changes. A set of novel experiments are performed to isolate the active role of the <span class="hlt">ocean</span> by comparing a fully coupled CO 2 quadrupling community Earth System <span class="hlt">Model</span> (CESM) simulation against a partially coupled one, where the effect of the <span class="hlt">ocean</span> circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective <span class="hlt">climate</span> sensitivity andmore » weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO 2 quadrupling in a slab <span class="hlt">ocean</span> <span class="hlt">model</span> configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45..306G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45..306G"><span>The Active Role of the <span class="hlt">Ocean</span> in the Temporal Evolution of <span class="hlt">Climate</span> Sensitivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai; Singh, Hansi A.</p> <p>2018-01-01</p> <p>The temporal evolution of the effective <span class="hlt">climate</span> sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and <span class="hlt">ocean</span> heat uptake (OHU), which in turn have been attributed to <span class="hlt">ocean</span> circulation changes. A set of novel experiments are performed to isolate the active role of the <span class="hlt">ocean</span> by comparing a fully coupled CO2 quadrupling community Earth System <span class="hlt">Model</span> (CESM) simulation against a partially coupled one, where the effect of the <span class="hlt">ocean</span> circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective <span class="hlt">climate</span> sensitivity and weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO2 quadrupling in a slab <span class="hlt">ocean</span> <span class="hlt">model</span> configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1420443','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1420443"><span>The Active Role of the <span class="hlt">Ocean</span> in the Temporal Evolution of <span class="hlt">Climate</span> Sensitivity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai</p> <p></p> <p>Here, the temporal evolution of the effective <span class="hlt">climate</span> sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and <span class="hlt">ocean</span> heat uptake (OHU), which in turn have been attributed to <span class="hlt">ocean</span> circulation changes. A set of novel experiments are performed to isolate the active role of the <span class="hlt">ocean</span> by comparing a fully coupled CO 2 quadrupling community Earth System <span class="hlt">Model</span> (CESM) simulation against a partially coupled one, where the effect of the <span class="hlt">ocean</span> circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective <span class="hlt">climate</span> sensitivity andmore » weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO 2 quadrupling in a slab <span class="hlt">ocean</span> <span class="hlt">model</span> configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1279014-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1279014-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities"><span><span class="hlt">Ocean</span> acidification over the next three centuries using a simple global <span class="hlt">climate</span> carbon-cycle <span class="hlt">model</span>: projections and sensitivities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Hartin, Corinne A.; Bond-Lamberty, Benjamin; Patel, Pralit; ...</p> <p>2016-08-01</p> <p>Continued <span class="hlt">oceanic</span> uptake of anthropogenic CO 2 is projected to significantly alter the chemistry of the upper <span class="hlt">oceans</span> over the next three centuries, with potentially serious consequences for marine ecosystems. Relatively few <span class="hlt">models</span> have the capability to make projections of <span class="hlt">ocean</span> acidification, limiting our ability to assess the impacts and probabilities of <span class="hlt">ocean</span> changes. In this study we examine the ability of Hector v1.1, a reduced-form global <span class="hlt">model</span>, to project changes in the upper <span class="hlt">ocean</span> carbonate system over the next three centuries, and quantify the <span class="hlt">model</span>'s sensitivity to parametric inputs. Hector is run under prescribed emission pathways from the Representativemore » Concentration Pathways (RCPs) and compared to both observations and a suite of Coupled <span class="hlt">Model</span> Intercomparison (CMIP5) <span class="hlt">model</span> outputs. Current observations confirm that <span class="hlt">ocean</span> acidification is already taking place, and CMIP5 <span class="hlt">models</span> project significant changes occurring to 2300. Hector is consistent with the observational record within both the high- (> 55°) and low-latitude <span class="hlt">oceans</span> (< 55°). The <span class="hlt">model</span> projects low-latitude surface <span class="hlt">ocean</span> pH to decrease from preindustrial levels of 8.17 to 7.77 in 2100, and to 7.50 in 2300; aragonite saturation levels (Ω Ar) decrease from 4.1 units to 2.2 in 2100 and 1.4 in 2300 under RCP 8.5. These magnitudes and trends of <span class="hlt">ocean</span> acidification within Hector are largely consistent with the CMIP5 <span class="hlt">model</span> outputs, although we identify some small biases within Hector's carbonate system. Of the parameters tested, changes in [H +] are most sensitive to parameters that directly affect atmospheric CO 2 concentrations – Q 10 (terrestrial respiration temperature response) as well as changes in <span class="hlt">ocean</span> circulation, while changes in Ω Ar saturation levels are sensitive to changes in <span class="hlt">ocean</span> salinity and Q 10. We conclude that Hector is a robust tool well suited for rapid <span class="hlt">ocean</span> acidification projections and sensitivity analyses, and it is capable of emulating both current</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1279014-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1279014-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities"><span><span class="hlt">Ocean</span> acidification over the next three centuries using a simple global <span class="hlt">climate</span> carbon-cycle <span class="hlt">model</span>: projections and sensitivities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hartin, Corinne A.; Bond-Lamberty, Benjamin; Patel, Pralit</p> <p></p> <p>Continued <span class="hlt">oceanic</span> uptake of anthropogenic CO 2 is projected to significantly alter the chemistry of the upper <span class="hlt">oceans</span> over the next three centuries, with potentially serious consequences for marine ecosystems. Relatively few <span class="hlt">models</span> have the capability to make projections of <span class="hlt">ocean</span> acidification, limiting our ability to assess the impacts and probabilities of <span class="hlt">ocean</span> changes. In this study we examine the ability of Hector v1.1, a reduced-form global <span class="hlt">model</span>, to project changes in the upper <span class="hlt">ocean</span> carbonate system over the next three centuries, and quantify the <span class="hlt">model</span>'s sensitivity to parametric inputs. Hector is run under prescribed emission pathways from the Representativemore » Concentration Pathways (RCPs) and compared to both observations and a suite of Coupled <span class="hlt">Model</span> Intercomparison (CMIP5) <span class="hlt">model</span> outputs. Current observations confirm that <span class="hlt">ocean</span> acidification is already taking place, and CMIP5 <span class="hlt">models</span> project significant changes occurring to 2300. Hector is consistent with the observational record within both the high- (> 55°) and low-latitude <span class="hlt">oceans</span> (< 55°). The <span class="hlt">model</span> projects low-latitude surface <span class="hlt">ocean</span> pH to decrease from preindustrial levels of 8.17 to 7.77 in 2100, and to 7.50 in 2300; aragonite saturation levels (Ω Ar) decrease from 4.1 units to 2.2 in 2100 and 1.4 in 2300 under RCP 8.5. These magnitudes and trends of <span class="hlt">ocean</span> acidification within Hector are largely consistent with the CMIP5 <span class="hlt">model</span> outputs, although we identify some small biases within Hector's carbonate system. Of the parameters tested, changes in [H +] are most sensitive to parameters that directly affect atmospheric CO 2 concentrations – Q 10 (terrestrial respiration temperature response) as well as changes in <span class="hlt">ocean</span> circulation, while changes in Ω Ar saturation levels are sensitive to changes in <span class="hlt">ocean</span> salinity and Q 10. We conclude that Hector is a robust tool well suited for rapid <span class="hlt">ocean</span> acidification projections and sensitivity analyses, and it is capable of emulating both current</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1340795-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1340795-ocean-acidification-over-next-three-centuries-using-simple-global-climate-carbon-cycle-model-projections-sensitivities"><span><span class="hlt">Ocean</span> acidification over the next three centuries using a simple global <span class="hlt">climate</span> carbon-cycle <span class="hlt">model</span>: projections and sensitivities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hartin, Corinne A.; Bond-Lamberty, Benjamin; Patel, Pralit</p> <p></p> <p>Continued <span class="hlt">oceanic</span> uptake of anthropogenic CO 2 is projected to significantly alter the chemistry of the upper <span class="hlt">oceans</span> over the next three centuries, with potentially serious consequences for marine ecosystems. Relatively few <span class="hlt">models</span> have the capability to make projections of <span class="hlt">ocean</span> acidification, limiting our ability to assess the impacts and probabilities of <span class="hlt">ocean</span> changes. In this study we examine the ability of Hector v1.1, a reduced-form global <span class="hlt">model</span>, to project changes in the upper <span class="hlt">ocean</span> carbonate system over the next three centuries, and quantify the <span class="hlt">model</span>'s sensitivity to parametric inputs. Hector is run under prescribed emission pathways from the Representativemore » Concentration Pathways (RCPs) and compared to both observations and a suite of Coupled <span class="hlt">Model</span> Intercomparison (CMIP5) <span class="hlt">model</span> outputs. Current observations confirm that <span class="hlt">ocean</span> acidification is already taking place, and CMIP5 <span class="hlt">models</span> project significant changes occurring to 2300. Hector is consistent with the observational record within both the high- (> 55°) and low-latitude <span class="hlt">oceans</span> (< 55°). The <span class="hlt">model</span> projects low-latitude surface <span class="hlt">ocean</span> pH to decrease from preindustrial levels of 8.17 to 7.77 in 2100, and to 7.50 in 2300; aragonite saturation levels (Ω Ar) decrease from 4.1 units to 2.2 in 2100 and 1.4 in 2300 under RCP 8.5. These magnitudes and trends of <span class="hlt">ocean</span> acidification within Hector are largely consistent with the CMIP5 <span class="hlt">model</span> outputs, although we identify some small biases within Hector's carbonate system. Of the parameters tested, changes in [H +] are most sensitive to parameters that directly affect atmospheric CO 2 concentrations – Q 10 (terrestrial respiration temperature response) as well as changes in <span class="hlt">ocean</span> circulation, while changes in Ω Ar saturation levels are sensitive to changes in <span class="hlt">ocean</span> salinity and Q 10. We conclude that Hector is a robust tool well suited for rapid <span class="hlt">ocean</span> acidification projections and sensitivity analyses, and it is capable of emulating both current</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940006244','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940006244"><span>Topex/Poseidon: A United States/France mission. Oceanography from space: The <span class="hlt">oceans</span> and <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>The TOPEX/POSEIDON space mission, sponsored by NASA and France's space agency, the Centre National d'Etudes Spatiales (CNES), will give new observations of the Earth from space to gain a quantitative understanding of the role of <span class="hlt">ocean</span> currents in <span class="hlt">climate</span> change. Rising atmospheric concentrations of carbon dioxide and other 'greenhouse gases' produced as a result of human activities could generate a global warming, followed by an associated rise in sea level. The satellite will use radar altimetry to measure sea-surface height and will be tracked by three independent systems to yield accurate topographic maps over the dimensions of entire <span class="hlt">ocean</span> basins. The satellite data, together with the Tropical <span class="hlt">Ocean</span> and Global Atmosphere (TOGA) program and the World <span class="hlt">Ocean</span> Circulation Experiment (WOCE) measurements, will be analyzed by an international scientific team. By merging the satellite observations with TOGA and WOCE findings, the scientists will establish the extensive data base needed for the quantitative description and computer <span class="hlt">modeling</span> of <span class="hlt">ocean</span> circulation. The <span class="hlt">ocean</span> <span class="hlt">models</span> will eventually be coupled with atmospheric <span class="hlt">models</span> to lay the foundation for predictions of global <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850039007&hterms=oceans+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Doceans%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850039007&hterms=oceans+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Doceans%2Bclimate%2Bchanges"><span>The seasonal response of the Held-Suarez <span class="hlt">climate</span> <span class="hlt">model</span> to prescribed <span class="hlt">ocean</span> temperature anomalies. II - Dynamical analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Phillips, T. J.</p> <p>1984-01-01</p> <p>The heating associated with equatorial, subtropical, and midlatitude <span class="hlt">ocean</span> temperature anamolies in the Held-Suarez <span class="hlt">climate</span> <span class="hlt">model</span> is analyzed. The local and downstream response to the anomalies is analyzed, first by examining the seasonal variation in heating associated with each <span class="hlt">ocean</span> temperature anomaly, and then by combining knowledge of the heating with linear dynamical theory in order to develop a more comprehensive explanation of the seasonal variation in local and downstream atmospheric response to each anomaly. The extent to which the linear theory of propagating waves can assist the interpretation of the remote cross-latitudinal response of the <span class="hlt">model</span> to the <span class="hlt">ocean</span> temperature anomalies is considered. Alternative hypotheses that attempt to avoid the contradictions inherent in a strict application of linear theory are investigated, and the impact of sampling errors on the assessment of statistical significance is also examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6729T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6729T"><span>Emerging <span class="hlt">climate</span> change signals in the interior <span class="hlt">ocean</span> oxygen content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tjiputra, Jerry; Goris, Nadine; Schwinger, Jörg; Lauvset, Siv</p> <p>2017-04-01</p> <p>Earth System <span class="hlt">Models</span> (ESMs) indicate that human-induced <span class="hlt">climate</span> change will introduce spatially heterogeneous modifications of dissolved oxygen in the North Atlantic. In the upper <span class="hlt">ocean</span>, an increase (decrease) is predicted at low (high) latitude. Oxygen increase is driven by a reduction of the oxygen consumption for biological remineralization while warming-induced reduction in air-sea fluxes and increase in remineralization due to weaker overturning circulation lead to the projected decrease. In the interior <span class="hlt">ocean</span>, modifications in the apparent oxygen utilization (AOU) dominate the overall oxygen changes. Moreover, for the southern subpolar gyre, both observations and <span class="hlt">model</span> hindcast indicate a close relationship between interior <span class="hlt">ocean</span> oxygen and the subpolar gyre index. Over the 21st century, all ESMs consistently project a steady weakening of this index and consequently the oxygen. Our finding shows that <span class="hlt">climate</span> change-induced oxygen depletion in the interior has likely occurred and can already be detected. Nevertheless, considering the observational uncertainties, we show that in the proximity of southern subpolar gyre the projected interior trend is sufficiently large enough for early detection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014BGD....1110537K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014BGD....1110537K"><span>iMarNet: an <span class="hlt">ocean</span> biogeochemistry <span class="hlt">model</span> inter-comparison project within a common physical <span class="hlt">ocean</span> <span class="hlt">modelling</span> framework</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwiatkowski, L.; Yool, A.; Allen, J. I.; Anderson, T. R.; Barciela, R.; Buitenhuis, E. T.; Butenschön, M.; Enright, C.; Halloran, P. R.; Le Quéré, C.; de Mora, L.; Racault, M.-F.; Sinha, B.; Totterdell, I. J.; Cox, P. M.</p> <p>2014-07-01</p> <p><span class="hlt">Ocean</span> biogeochemistry (OBGC) <span class="hlt">models</span> span a wide range of complexities from highly simplified, nutrient-restoring schemes, through nutrient-phytoplankton-zooplankton-detritus (NPZD) <span class="hlt">models</span> that crudely represent the marine biota, through to <span class="hlt">models</span> that represent a broader trophic structure by grouping organisms as plankton functional types (PFT) based on their biogeochemical role (Dynamic Green <span class="hlt">Ocean</span> <span class="hlt">Models</span>; DGOM) and ecosystem <span class="hlt">models</span> which group organisms by ecological function and trait. OBGC <span class="hlt">models</span> are now integral components of Earth System <span class="hlt">Models</span> (ESMs), but they compete for computing resources with higher resolution dynamical setups and with other components such as atmospheric chemistry and terrestrial vegetation schemes. As such, the choice of OBGC in ESMs needs to balance <span class="hlt">model</span> complexity and realism alongside relative computing cost. Here, we present an inter-comparison of six OBGC <span class="hlt">models</span> that were candidates for implementation within the next UK Earth System <span class="hlt">Model</span> (UKESM1). The <span class="hlt">models</span> cover a large range of biological complexity (from 7 to 57 tracers) but all include representations of at least the nitrogen, carbon, alkalinity and oxygen cycles. Each OBGC <span class="hlt">model</span> was coupled to the Nucleus for the European <span class="hlt">Modelling</span> of the <span class="hlt">Ocean</span> (NEMO) <span class="hlt">ocean</span> general circulation <span class="hlt">model</span> (GCM), and results from physically identical hindcast simulations were compared. <span class="hlt">Model</span> skill was evaluated for biogeochemical metrics of global-scale bulk properties using conventional statistical techniques. The computing cost of each <span class="hlt">model</span> was also measured in standardised tests run at two resource levels. No <span class="hlt">model</span> is shown to consistently outperform or underperform all other <span class="hlt">models</span> across all metrics. Nonetheless, the simpler <span class="hlt">models</span> that are easier to tune are broadly closer to observations across a number of fields, and thus offer a high-efficiency option for ESMs that prioritise high resolution <span class="hlt">climate</span> dynamics. However, simpler <span class="hlt">models</span> provide limited insight into more complex marine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..379M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..379M"><span>Statistical link between external <span class="hlt">climate</span> forcings and modes of <span class="hlt">ocean</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Malik, Abdul; Brönnimann, Stefan; Perona, Paolo</p> <p>2017-07-01</p> <p>In this study we investigate statistical link between external <span class="hlt">climate</span> forcings and modes of <span class="hlt">ocean</span> variability on inter-annual (3-year) to centennial (100-year) timescales using de-trended semi-partial-cross-correlation analysis technique. To investigate this link we employ observations (AD 1854-1999), <span class="hlt">climate</span> proxies (AD 1600-1999), and coupled Atmosphere-<span class="hlt">Ocean</span>-Chemistry <span class="hlt">Climate</span> <span class="hlt">Model</span> simulations with SOCOL-MPIOM (AD 1600-1999). We find robust statistical evidence that Atlantic multi-decadal oscillation (AMO) has intrinsic positive correlation with solar activity in all datasets employed. The strength of the relationship between AMO and solar activity is modulated by volcanic eruptions and complex interaction among modes of <span class="hlt">ocean</span> variability. The observational dataset reveals that El Niño southern oscillation (ENSO) has statistically significant negative intrinsic correlation with solar activity on decadal to multi-decadal timescales (16-27-year) whereas there is no evidence of a link on a typical ENSO timescale (2-7-year). In the observational dataset, the volcanic eruptions do not have a link with AMO on a typical AMO timescale (55-80-year) however the long-term datasets (proxies and SOCOL-MPIOM output) show that volcanic eruptions have intrinsic negative correlation with AMO on inter-annual to multi-decadal timescales. The Pacific decadal oscillation has no link with solar activity, however, it has positive intrinsic correlation with volcanic eruptions on multi-decadal timescales (47-54-year) in reconstruction and decadal to multi-decadal timescales (16-32-year) in <span class="hlt">climate</span> <span class="hlt">model</span> simulations. We also find evidence of a link between volcanic eruptions and ENSO, however, the sign of relationship is not consistent between observations/proxies and <span class="hlt">climate</span> <span class="hlt">model</span> simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27935174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27935174"><span>Going with the flow: the role of <span class="hlt">ocean</span> circulation in global marine ecosystems under a changing <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Gennip, Simon J; Popova, Ekaterina E; Yool, Andrew; Pecl, Gretta T; Hobday, Alistair J; Sorte, Cascade J B</p> <p>2017-07-01</p> <p><span class="hlt">Ocean</span> warming, acidification, deoxygenation and reduced productivity are widely considered to be the major stressors to <span class="hlt">ocean</span> ecosystems induced by emissions of CO 2 . However, an overlooked stressor is the change in <span class="hlt">ocean</span> circulation in response to <span class="hlt">climate</span> change. Strong changes in the intensity and position of the western boundary currents have already been observed, and the consequences of such changes for ecosystems are beginning to emerge. In this study, we address <span class="hlt">climatically</span> induced changes in <span class="hlt">ocean</span> circulation on a global scale but relevant to propagule dispersal for species inhabiting global shelf ecosystems, using a high-resolution global <span class="hlt">ocean</span> <span class="hlt">model</span> run under the IPCC RCP 8.5 scenario. The ¼ degree <span class="hlt">model</span> resolution allows improved regional realism of the <span class="hlt">ocean</span> circulation beyond that of available CMIP5-class <span class="hlt">models</span>. We use a Lagrangian approach forced by <span class="hlt">modelled</span> <span class="hlt">ocean</span> circulation to simulate the circulation pathways that disperse planktonic life stages. Based on trajectory backtracking, we identify present-day coastal retention, dominant flow and dispersal range for coastal regions at the global scale. Projecting into the future, we identify areas of the strongest projected circulation change and present regional examples with the most significant modifications in their dominant pathways. <span class="hlt">Climatically</span> induced changes in <span class="hlt">ocean</span> circulation should be considered as an additional stressor of marine ecosystems in a similar way to <span class="hlt">ocean</span> warming or acidification. © 2017 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ClDy...10..313H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ClDy...10..313H"><span>A zonally averaged, three-basin <span class="hlt">ocean</span> circulation <span class="hlt">model</span> for <span class="hlt">climate</span> studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hovine, S.; Fichefet, T.</p> <p>1994-09-01</p> <p>A two-dimensional, three-basin <span class="hlt">ocean</span> <span class="hlt">model</span> suitable for long-term <span class="hlt">climate</span> studies is developed. The <span class="hlt">model</span> is based on the zonally averaged form of the primitive equations written in spherical coordinates. The east-west density difference which arises upon averaging the momentum equations is taken to be proportional to the meridional density gradient. Lateral exchanges of heat and salt between the basins are explicitly resolved. Moreover, the <span class="hlt">model</span> includes bottom topography and has representations of the Arctic <span class="hlt">Ocean</span> and of the Weddell and Ross seas. Under realistic restoring boundary conditions, the <span class="hlt">model</span> reproduces the global conveyor belt: deep water is formed in the Atlantic between 60 and 70°N at a rate of about 17 Sv (1 Sv=106 m3 s-1) and in the vicinity of the Antarctic continent, while the Indian and Pacific basins show broad upwelling. Superimposed on this thermohaline circulation are vigorous wind-driven cells in the upper thermocline. The simulated temperature and salinity fields and the computed meridional heat transport compare reasonably well with the observational estimates. When mixed boundary conditions (i.e., a restoring condition on sea-surface temperature and flux condition on sea-surface salinity) are applied, the <span class="hlt">model</span> exhibits an irregular behavior before reaching a steady state characterized by self-sustained oscillations of 8.5-y period. The conveyor-belt circulation always results at this stage. A series of perturbation experiments illustrates the ability of the <span class="hlt">model</span> to reproduce different steady-state circulations under mixed boundary conditions. Finally, the <span class="hlt">model</span> sensitivity to various factors is examined. This sensitivity study reveals that the bottom topography and the presence of a submarine meridional ridge in the zone of the Drake Passage play a crucial role in determining the properties of the <span class="hlt">model</span> bottom-water masses. The importance of the seasonality of the surface forcing is also stressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150295','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150295"><span>A perspective on sustained marine observations for <span class="hlt">climate</span> <span class="hlt">modelling</span> and prediction</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dunstone, Nick J.</p> <p>2014-01-01</p> <p>Here, I examine some of the many varied ways in which sustained global <span class="hlt">ocean</span> observations are used in numerical <span class="hlt">modelling</span> activities. In particular, I focus on the use of <span class="hlt">ocean</span> observations to initialize predictions in <span class="hlt">ocean</span> and <span class="hlt">climate</span> <span class="hlt">models</span>. Examples are also shown of how <span class="hlt">models</span> can be used to assess the impact of both current <span class="hlt">ocean</span> observations and to simulate that of potential new <span class="hlt">ocean</span> observing platforms. The <span class="hlt">ocean</span> has never been better observed than it is today and similarly <span class="hlt">ocean</span> <span class="hlt">models</span> have never been as capable at representing the real <span class="hlt">ocean</span> as they are now. However, there remain important unanswered questions that can likely only be addressed via future improvements in <span class="hlt">ocean</span> observations. In particular, <span class="hlt">ocean</span> observing systems need to respond to the needs of the burgeoning field of near-term <span class="hlt">climate</span> predictions. Although new <span class="hlt">ocean</span> observing platforms promise exciting new discoveries, there is a delicate balance to be made between their funding and that of the current <span class="hlt">ocean</span> observing system. Here, I identify the need to secure long-term funding for <span class="hlt">ocean</span> observing platforms as they mature, from a mainly research exercise to an operational system for sustained observation over <span class="hlt">climate</span> change time scales. At the same time, considerable progress continues to be made via ship-based observing campaigns and I highlight some that are dedicated to addressing uncertainties in key <span class="hlt">ocean</span> <span class="hlt">model</span> parametrizations. The use of <span class="hlt">ocean</span> observations to understand the prominent long time scale changes observed in the North Atlantic is another focus of this paper. The exciting first decade of monitoring of the Atlantic meridional overturning circulation by the RAPID-MOCHA array is highlighted. The use of <span class="hlt">ocean</span> and <span class="hlt">climate</span> <span class="hlt">models</span> as tools to further probe the drivers of variability seen in such time series is another exciting development. I also discuss the need for a concerted combined effort from <span class="hlt">climate</span> <span class="hlt">models</span> and <span class="hlt">ocean</span> observations in order to understand the current slow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25157195','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25157195"><span>A perspective on sustained marine observations for <span class="hlt">climate</span> <span class="hlt">modelling</span> and prediction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dunstone, Nick J</p> <p>2014-09-28</p> <p>Here, I examine some of the many varied ways in which sustained global <span class="hlt">ocean</span> observations are used in numerical <span class="hlt">modelling</span> activities. In particular, I focus on the use of <span class="hlt">ocean</span> observations to initialize predictions in <span class="hlt">ocean</span> and <span class="hlt">climate</span> <span class="hlt">models</span>. Examples are also shown of how <span class="hlt">models</span> can be used to assess the impact of both current <span class="hlt">ocean</span> observations and to simulate that of potential new <span class="hlt">ocean</span> observing platforms. The <span class="hlt">ocean</span> has never been better observed than it is today and similarly <span class="hlt">ocean</span> <span class="hlt">models</span> have never been as capable at representing the real <span class="hlt">ocean</span> as they are now. However, there remain important unanswered questions that can likely only be addressed via future improvements in <span class="hlt">ocean</span> observations. In particular, <span class="hlt">ocean</span> observing systems need to respond to the needs of the burgeoning field of near-term <span class="hlt">climate</span> predictions. Although new <span class="hlt">ocean</span> observing platforms promise exciting new discoveries, there is a delicate balance to be made between their funding and that of the current <span class="hlt">ocean</span> observing system. Here, I identify the need to secure long-term funding for <span class="hlt">ocean</span> observing platforms as they mature, from a mainly research exercise to an operational system for sustained observation over <span class="hlt">climate</span> change time scales. At the same time, considerable progress continues to be made via ship-based observing campaigns and I highlight some that are dedicated to addressing uncertainties in key <span class="hlt">ocean</span> <span class="hlt">model</span> parametrizations. The use of <span class="hlt">ocean</span> observations to understand the prominent long time scale changes observed in the North Atlantic is another focus of this paper. The exciting first decade of monitoring of the Atlantic meridional overturning circulation by the RAPID-MOCHA array is highlighted. The use of <span class="hlt">ocean</span> and <span class="hlt">climate</span> <span class="hlt">models</span> as tools to further probe the drivers of variability seen in such time series is another exciting development. I also discuss the need for a concerted combined effort from <span class="hlt">climate</span> <span class="hlt">models</span> and <span class="hlt">ocean</span> observations in order to understand the current slow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMED13B3457M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMED13B3457M"><span>SEA Semester Undergraduates Research the <span class="hlt">Ocean</span>'s Role in <span class="hlt">Climate</span> Systems in the Pacific <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, A. W.; Becker, M. K.; Grabb, K. C.</p> <p>2014-12-01</p> <p>Sea Education Association (SEA)'s fully accredited <span class="hlt">Oceans</span> & <span class="hlt">Climate</span> SEA Semester program provides upper-level science undergraduates a unique opportunity to explore the <span class="hlt">ocean</span>'s role in the global <span class="hlt">climate</span> system as they conduct real-world oceanographic research and gain first-hand understanding of and appreciation for the collaborative nature of the scientific research process. <span class="hlt">Oceans</span> & <span class="hlt">Climate</span> is an interdisciplinary science and policy semester in which students also explore public policy perspectives to learn how scientific knowledge is used in making <span class="hlt">climate</span>-related policy. Working first at SEA's shore campus, students collaborate with SEA faculty and other researchers in the local Woods Hole scientific community to design and develop an original research project to be completed at sea. Students then participate as full, working members of the scientific team and sailing crew aboard the 134-foot brigantine SSV Robert C. Seamans; they conduct extensive oceanographic sampling, manage shipboard operations, and complete and present the independent research project they designed onshore. <span class="hlt">Oceans</span> & <span class="hlt">Climate</span> SEA Semester Cruise S-250 sailed from San Diego to Tahiti on a 7-week, >4000nm voyage last fall (November-December 2013). This remote open-<span class="hlt">ocean</span> cruise track traversed subtropical and equatorial regions of the Pacific particularly well suited for a diverse range of <span class="hlt">climate</span>-focused studies. Furthermore, as SEA has regularly collected scientific data along similar Pacific cruise tracks for more than a decade, students often undertake projects that require time-series analyses. 18 undergraduates from 15 different colleges and universities participated in the S-250 program. Two examples of the many projects completed by S-250 students include a study of the possible relationship between tropical cyclone intensification, driven by warm sea surface temperatures, and the presence of barrier layers; and a study of nutrient cycling in the eastern Pacific, focusing on primary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.9449H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.9449H"><span>Connecting tropical <span class="hlt">climate</span> change with Southern <span class="hlt">Ocean</span> heat uptake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hwang, Yen-Ting; Xie, Shang-Ping; Deser, Clara; Kang, Sarah M.</p> <p>2017-09-01</p> <p>Under increasing greenhouse gas forcing, <span class="hlt">climate</span> <span class="hlt">models</span> project tropical warming that is greater in the Northern than the Southern Hemisphere, accompanied by a reduction in the northeast trade winds and a strengthening of the southeast trades. While the <span class="hlt">ocean</span>-atmosphere coupling indicates a positive feedback, what triggers the coupled asymmetry and favors greater warming in the northern tropics remains unclear. Far away from the tropics, the Southern <span class="hlt">Ocean</span> (SO) has been identified as the major region of <span class="hlt">ocean</span> heat uptake. Beyond its local effect on the magnitude of sea surface warming, we show by idealized <span class="hlt">modeling</span> experiments in a coupled slab <span class="hlt">ocean</span> configuration that enhanced SO heat uptake has a profound global impact. This SO-to-tropics connection is consistent with southward atmospheric energy transport across the equator. Enhanced SO heat uptake results in a zonally asymmetric La-Nina-like pattern of sea surface temperature change that not only affects tropical precipitation but also has influences on the Asian and North American monsoons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017694','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017694"><span><span class="hlt">Ocean</span> Biological Pump Sensitivities and Implications for <span class="hlt">Climate</span> Change Impacts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Romanou, Anastasia</p> <p>2013-01-01</p> <p>The <span class="hlt">ocean</span> is one of the principal reservoirs of CO2, a greenhouse gas, and therefore plays a crucial role in regulating Earth's <span class="hlt">climate</span>. Currently, the <span class="hlt">ocean</span> sequesters about a third of anthropogenic CO2 emissions, mitigating the human impact on <span class="hlt">climate</span>. At the same time, the deeper <span class="hlt">ocean</span> represents the largest carbon pool in the Earth System and processes that describe the transfer of carbon from the surface of the <span class="hlt">ocean</span> to depth are intimately linked to the effectiveness of carbon sequestration.The <span class="hlt">ocean</span> biological pump (OBP), which involves several biogeochemical processes, is a major pathway for transfer of carbon from the surface mixed layer into the <span class="hlt">ocean</span> interior. About 75 of the carbon vertical gradient is due to the carbon pump with only 25 attributed to the solubility pump. However, the relative importance and role of the two pumps is poorly constrained. OBP is further divided to the organic carbon pump (soft tissue pump) and the carbonate pump, with the former exporting about 10 times more carbon than the latter through processes like remineralization.Major uncertainties about OBP, and hence in the carbon uptake and sequestration, stem from uncertainties in processes involved in OBP such as particulate organicinorganic carbon sinkingsettling, remineralization, microbial degradation of DOC and uptakegrowth rate changes of the <span class="hlt">ocean</span> biology. The deep <span class="hlt">ocean</span> is a major sink of atmospheric CO2 in scales of hundreds to thousands of years, but how the export efficiency (i.e. the fraction of total carbon fixation at the surface that is transported at depth) is affected by <span class="hlt">climate</span> change remains largely undetermined. These processes affect the <span class="hlt">ocean</span> chemistry (alkalinity, pH, DIC, particulate and dissolved organic carbon) as well as the ecology (biodiversity, functional groups and their interactions) in the <span class="hlt">ocean</span>. It is important to have a rigorous, quantitative understanding of the uncertainties involved in the observational measurements, the <span class="hlt">models</span> and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150019892','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150019892"><span><span class="hlt">Ocean</span>-Atmosphere Coupled <span class="hlt">Model</span> Simulations of Precipitation in the Central Andes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nicholls, Stephen D.; Mohr, Karen I.</p> <p>2015-01-01</p> <p>The meridional extent and complex orography of the South American continent contributes to a wide diversity of <span class="hlt">climate</span> regimes ranging from hyper-arid deserts to tropical rainforests to sub-polar highland regions. In addition, South American meteorology and <span class="hlt">climate</span> are also made further complicated by ENSO, a powerful coupled <span class="hlt">ocean</span>-atmosphere phenomenon. <span class="hlt">Modelling</span> studies in this region have typically resorted to either atmospheric mesoscale or atmosphere-<span class="hlt">ocean</span> coupled global <span class="hlt">climate</span> <span class="hlt">models</span>. The latter offers full physics and high spatial resolution, but it is computationally inefficient typically lack an interactive <span class="hlt">ocean</span>, whereas the former offers high computational efficiency and <span class="hlt">ocean</span>-atmosphere coupling, but it lacks adequate spatial and temporal resolution to adequate resolve the complex orography and explicitly simulate precipitation. Explicit simulation of precipitation is vital in the Central Andes where rainfall rates are light (0.5-5 mm hr-1), there is strong seasonality, and most precipitation is associated with weak mesoscale-organized convection. Recent increases in both computational power and <span class="hlt">model</span> development have led to the advent of coupled <span class="hlt">ocean</span>-atmosphere mesoscale <span class="hlt">models</span> for both weather and <span class="hlt">climate</span> study applications. These <span class="hlt">modelling</span> systems, while computationally expensive, include two-way <span class="hlt">ocean</span>-atmosphere coupling, high resolution, and explicit simulation of precipitation. In this study, we use the Coupled <span class="hlt">Ocean</span>-Atmosphere-Wave-Sediment Transport (COAWST), a fully-coupled mesoscale atmosphere-<span class="hlt">ocean</span> <span class="hlt">modeling</span> system. Previous work has shown COAWST to reasonably simulate the entire 2003-2004 wet season (Dec-Feb) as validated against both satellite and <span class="hlt">model</span> analysis data when ECMWF interim analysis data were used for boundary conditions on a 27-9-km grid configuration (Outer grid extent: 60.4S to 17.7N and 118.6W to 17.4W).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRC..119.7660G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRC..119.7660G"><span>The Southwest Pacific <span class="hlt">Ocean</span> circulation and <span class="hlt">climate</span> experiment (SPICE)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganachaud, A.; Cravatte, S.; Melet, A.; Schiller, A.; Holbrook, N. J.; Sloyan, B. M.; Widlansky, M. J.; Bowen, M.; Verron, J.; Wiles, P.; Ridgway, K.; Sutton, P.; Sprintall, J.; Steinberg, C.; Brassington, G.; Cai, W.; Davis, R.; Gasparin, F.; Gourdeau, L.; Hasegawa, T.; Kessler, W.; Maes, C.; Takahashi, K.; Richards, K. J.; Send, U.</p> <p>2014-11-01</p> <p>The Southwest Pacific <span class="hlt">Ocean</span> Circulation and <span class="hlt">Climate</span> Experiment (SPICE) is an international research program under the auspices of CLIVAR. The key objectives are to understand the Southwest Pacific <span class="hlt">Ocean</span> circulation and the South Pacific Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale <span class="hlt">climate</span> patterns. South Pacific thermocline waters are transported in the westward flowing South Equatorial Current (SEC) toward Australia and Papua-New Guinea. On its way, the SEC encounters the numerous islands and straits of the Southwest Pacific and forms boundary currents and jets that eventually redistribute water to the equator and high latitudes. The transit in the Coral, Solomon, and Tasman Seas is of great importance to the <span class="hlt">climate</span> system because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate the El Niño-Southern Oscillation, while the southward transports influence the <span class="hlt">climate</span> and biodiversity in the Tasman Sea. After 7 years of substantial in situ <span class="hlt">oceanic</span> observational and <span class="hlt">modeling</span> efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. This paper provides a review of recent advancements and discusses our current knowledge gaps and important emerging research directions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013440','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013440"><span><span class="hlt">Climate</span> <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Druyan, Leonard M.</p> <p>2012-01-01</p> <p><span class="hlt">Climate</span> <span class="hlt">models</span> is a very broad topic, so a single volume can only offer a small sampling of relevant research activities. This volume of 14 chapters includes descriptions of a variety of <span class="hlt">modeling</span> studies for a variety of geographic regions by an international roster of authors. The <span class="hlt">climate</span> research community generally uses the rubric <span class="hlt">climate</span> <span class="hlt">models</span> to refer to organized sets of computer instructions that produce simulations of <span class="hlt">climate</span> evolution. The code is based on physical relationships that describe the shared variability of meteorological parameters such as temperature, humidity, precipitation rate, circulation, radiation fluxes, etc. Three-dimensional <span class="hlt">climate</span> <span class="hlt">models</span> are integrated over time in order to compute the temporal and spatial variations of these parameters. <span class="hlt">Model</span> domains can be global or regional and the horizontal and vertical resolutions of the computational grid vary from <span class="hlt">model</span> to <span class="hlt">model</span>. Considering the entire <span class="hlt">climate</span> system requires accounting for interactions between solar insolation, atmospheric, <span class="hlt">oceanic</span> and continental processes, the latter including land hydrology and vegetation. <span class="hlt">Model</span> simulations may concentrate on one or more of these components, but the most sophisticated <span class="hlt">models</span> will estimate the mutual interactions of all of these environments. Advances in computer technology have prompted investments in more complex <span class="hlt">model</span> configurations that consider more phenomena interactions than were possible with yesterday s computers. However, not every attempt to add to the computational layers is rewarded by better <span class="hlt">model</span> performance. Extensive research is required to test and document any advantages gained by greater sophistication in <span class="hlt">model</span> formulation. One purpose for publishing <span class="hlt">climate</span> <span class="hlt">model</span> research results is to present purported advances for evaluation by the scientific community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GBioC..18.3003S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GBioC..18.3003S"><span>Response of <span class="hlt">ocean</span> ecosystems to <span class="hlt">climate</span> warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarmiento, J. L.; Slater, R.; Barber, R.; Bopp, L.; Doney, S. C.; Hirst, A. C.; Kleypas, J.; Matear, R.; Mikolajewicz, U.; Monfray, P.; Soldatov, V.; Spall, S. A.; Stouffer, R.</p> <p>2004-09-01</p> <p>We examine six different coupled <span class="hlt">climate</span> <span class="hlt">model</span> simulations to determine the <span class="hlt">ocean</span> biological response to <span class="hlt">climate</span> warming between the beginning of the industrial revolution and 2050. We use vertical velocity, maximum winter mixed layer depth, and sea ice cover to define six biomes. <span class="hlt">Climate</span> warming leads to a contraction of the highly productive marginal sea ice biome by 42% in the Northern Hemisphere and 17% in the Southern Hemisphere, and leads to an expansion of the low productivity permanently stratified subtropical gyre biome by 4.0% in the Northern Hemisphere and 9.4% in the Southern Hemisphere. In between these, the subpolar gyre biome expands by 16% in the Northern Hemisphere and 7% in the Southern Hemisphere, and the seasonally stratified subtropical gyre contracts by 11% in both hemispheres. The low-latitude (mostly coastal) upwelling biome area changes only modestly. Vertical stratification increases, which would be expected to decrease nutrient supply everywhere, but increase the growing season length in high latitudes. We use satellite <span class="hlt">ocean</span> color and climatological observations to develop an empirical <span class="hlt">model</span> for predicting chlorophyll from the physical properties of the global warming simulations. Four features stand out in the response to global warming: (1) a drop in chlorophyll in the North Pacific due primarily to retreat of the marginal sea ice biome, (2) a tendency toward an increase in chlorophyll in the North Atlantic due to a complex combination of factors, (3) an increase in chlorophyll in the Southern <span class="hlt">Ocean</span> due primarily to the retreat of and changes at the northern boundary of the marginal sea ice zone, and (4) a tendency toward a decrease in chlorophyll adjacent to the Antarctic continent due primarily to freshening within the marginal sea ice zone. We use three different primary production algorithms to estimate the response of primary production to <span class="hlt">climate</span> warming based on our estimated chlorophyll concentrations. The three algorithms give</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ClDy...42..203D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ClDy...42..203D"><span>Indian <span class="hlt">Ocean</span> warming during 1958-2004 simulated by a <span class="hlt">climate</span> system <span class="hlt">model</span> and its mechanism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dong, Lu; Zhou, Tianjun; Wu, Bo</p> <p>2014-01-01</p> <p>The mechanism responsible for Indian <span class="hlt">Ocean</span> Sea surface temperature (SST) basin-wide warming trend during 1958-2004 is studied based on both observational data analysis and numerical experiments with a <span class="hlt">climate</span> system <span class="hlt">model</span> FGOALS-gl. To quantitatively estimate the relative contributions of external forcing (anthropogenic and natural forcing) and internal variability, three sets of numerical experiments are conducted, viz. an all forcing run forced by both anthropogenic forcing (greenhouse gases and sulfate aerosols) and natural forcing (solar constant and volcanic aerosols), a natural forcing run driven by only natural forcing, and a pre-industrial control run. The <span class="hlt">model</span> results are compared to the observations. The results show that the observed warming trend during 1958-2004 (0.5 K (47-year)-1) is largely attributed to the external forcing (more than 90 % of the total trend), while the residual is attributed to the internal variability. <span class="hlt">Model</span> results indicate that the anthropogenic forcing accounts for approximately 98.8 % contribution of the external forcing trend. Heat budget analysis shows that the surface latent heat flux due to atmosphere and surface longwave radiation, which are mainly associated with anthropogenic forcing, are in favor of the basin-wide warming trend. The basin-wide warming is not spatially uniform, but with an equatorial IOD-like pattern in <span class="hlt">climate</span> <span class="hlt">model</span>. The atmospheric processes, <span class="hlt">oceanic</span> processes and climatological latent heat flux together form an equatorial IOD-like warming pattern, and the <span class="hlt">oceanic</span> process is the most important in forming the zonal dipole pattern. Both the anthropogenic forcing and natural forcing result in easterly wind anomalies over the equator, which reduce the wind speed, thereby lead to less evaporation and warmer SST in the equatorial western basin. Based on Bjerknes feedback, the easterly wind anomalies uplift the thermocline, which is unfavorable to SST warming in the eastern basin, and contribute to SST</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5022A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5022A"><span>The effect of changing wind forcing on Antarctic ice shelf melting in high-resolution, global sea ice-<span class="hlt">ocean</span> simulations with the Accelerated <span class="hlt">Climate</span> <span class="hlt">Model</span> for Energy (ACME)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asay-Davis, Xylar; Price, Stephen; Petersen, Mark; Wolfe, Jonathan</p> <p>2017-04-01</p> <p>The capability for simulating sub-ice shelf circulation and submarine melting and freezing has recently been added to the U.S. Department of Energy's Accelerated <span class="hlt">Climate</span> <span class="hlt">Model</span> for Energy (ACME). With this new capability, we use an eddy permitting <span class="hlt">ocean</span> <span class="hlt">model</span> to conduct two sets of simulations in the spirit of Spence et al. (GRL, 41, 2014), who demonstrate increased warm water upwelling along the Antarctic coast in response to poleward shifting and strengthening of Southern <span class="hlt">Ocean</span> westerly winds. These characteristics, symptomatic of a positive Southern Annular Mode (SAM), are projected to continue into the 21st century under anthropogenic <span class="hlt">climate</span> change (Fyfe et al., J. Clim., 20, 2007). In our first simulation, we force the <span class="hlt">climate</span> <span class="hlt">model</span> using the standard CORE interannual forcing dataset (Large and Yeager; Clim. Dyn., 33, 2009). In our second simulation, we force our <span class="hlt">climate</span> <span class="hlt">model</span> using an altered version of CORE interannual forcing, based on the latter half of the full time series, which we take as a proxy for a future <span class="hlt">climate</span> state biased towards a positive SAM. We compare <span class="hlt">ocean</span> <span class="hlt">model</span> states and sub-ice shelf melt rates with observations, exploring sources of <span class="hlt">model</span> biases as well as the effects of the two forcing scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000070385&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000070385&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Docean%2Bclimate%2Bchanges"><span><span class="hlt">Ocean</span>-Atmosphere Interaction in <span class="hlt">Climate</span> Changes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, W. Timothy</p> <p>1999-01-01</p> <p>The diagram, which attests the El Nino teleconnection observed by the NASA Scatterometer (NSCAT) in 1997, is an example of the results of our research in air-sea interaction - the core component of our three-part contribution to the <span class="hlt">Climate</span> Variability Program. We have established an interplay among scientific research, which turns spacebased data into knowledge, a push in instrument technology, which improves observations of <span class="hlt">climate</span> variability, and an information system, which produces and disseminates new data to support our scientific research. Timothy Liu led the proposal for advanced technology, in response to the NASA Post-2002 Request for Information. The sensor was identified as a possible mission for continuous <span class="hlt">ocean</span> surface wind measurement at higher spatial resolution, and with the unique capability to measure <span class="hlt">ocean</span> surface salinity. He is participating in the Instrument Incubator Program to improve the antenna technology, and is initiating a study to integrate the concept on Japanese missions. He and his collaborators have set up a system to produce and disseminate high level (gridded) <span class="hlt">ocean</span> surface wind/stress data from NSCAT and European missions. The data system is being expanded to produce real-time gridded <span class="hlt">ocean</span> surface winds from Quikscat, and precipitation and evaporation from the Tropical Rain Measuring Mission. It will form the basis for a spacebased data analysis system which will include momentum, heat and water fluxes. The study on 1997 El Nino teleconnection illustrates our interdisciplinary and multisensor approach to study <span class="hlt">climate</span> variability. The diagram shows that the collapse of trade wind and the westerly wind anomalies in the central equatorial Pacific led to the equatorial <span class="hlt">ocean</span> warming. The equatorial wind anomalies are connected to the anomalous cyclonic wind pattern in the northeast Pacific. The anomalous warming along the west coast of the United States is the result of the movement of the pre-existing warm sea surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSHI14A1765G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSHI14A1765G"><span>Studying the impact of different <span class="hlt">climate</span> engineering techniques on <span class="hlt">ocean</span> acidification with the Max Planck Institute Earth System <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, M. F.; Ilyina, T.; Sonntag, S.</p> <p>2016-02-01</p> <p>In order to counterbalance the consequences of <span class="hlt">climate</span> change, different <span class="hlt">climate</span> engineering (CE) technologies have been suggested. Nonetheless, knowledge about their mitigation potential and side-effects remains sparse. <span class="hlt">Ocean</span> alkalinization (OA) is an <span class="hlt">ocean</span>-based carbon dioxide removal method, that aims at enhancing the natural process of weathering by which atmospheric CO2 is absorbed and stored in the <span class="hlt">ocean</span> via chemical sequestration. Large-scale afforestation can also boost the uptake of CO2 by terrestrial biological systems and it is commonly considered as CE method. Stratospheric sulfur injection is a solar radiation management technique that has been proposed in order to enhance the Earth's albedo, mimicking the release of sulfur particles into the atmosphere during volcanic eruptions and the subsequent decrease in surface atmospheric temperatures. We explore the mitigation potential and side-effects of these CE technologies using the Max Planck Institute Earth System <span class="hlt">Model</span>. Our scenarios are designed in order to test under what conditions it is possible to achieve a <span class="hlt">climate</span> state that resembles the one of the representative concentration pathway (RCP) 4.5 under RCP8.5 greenhouse gas emissions. Direct and indirect effects of the OA method on the <span class="hlt">oceanic</span> carbon cycle, differ strongly from those associated with afforestation and stratospheric sulfur injection. This is because they depend upon joint responses and synergies between different elements of the Earth system; thus, effects on the <span class="hlt">oceanic</span> carbon cycle are not intuitively understood. Changes in the strength of the marine carbon sink, seawater pH and saturation state of carbonate minerals will be discussed. Additionally, collateral changes in marine biota and <span class="hlt">ocean</span> biogeochemistry will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890009730','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890009730"><span>Multi-property <span class="hlt">modeling</span> of <span class="hlt">ocean</span> basin carbon fluxes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Volk, Tyler</p> <p>1988-01-01</p> <p>The objectives of this project were to elucidate the causal mechanisms in some of the most important features of the global <span class="hlt">ocean</span>/atomsphere carbon system. These included the interaction of physical and biological processes in the seasonal cycle of surface water pCo2, and links between productivity, surface chlorophyll, and the carbon cycle that would aid global <span class="hlt">modeling</span> efforts. In addition, several other areas of critical scientific interest involving links between the marine biosphere and the global carbon cycle were successfully pursued; specifically, a possible relation between phytoplankton emitted DMS and <span class="hlt">climate</span>, and a relation between the location of calcium carbonate burial in the <span class="hlt">ocean</span> and metamorphic source fluxes of CO2 to the atmosphere. Six published papers covering the following topics are summarized: (1) Mass extinctions, atmospheric sulphur and <span class="hlt">climatic</span> warming at the K/T boundary; (2) Sensitivity of <span class="hlt">climate</span> and atmospheric CO2 to deep-<span class="hlt">ocean</span> and shallow-<span class="hlt">ocean</span> carbonate burial; (3) Controls on CO2 sources and sinks in the earthscale surface <span class="hlt">ocean</span>; (4) pre-anthropogenic, earthscale patterns of delta pCO2 between <span class="hlt">ocean</span> and atmosphere; (5) Effect on atmospheric CO2 from seasonal variations in the high latitude <span class="hlt">ocean</span>; and (6) Limitations or relating <span class="hlt">ocean</span> surface chlorophyll to productivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPO33C..02G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPO33C..02G"><span>Southwest Pacific <span class="hlt">Ocean</span> Circulation and <span class="hlt">Climate</span> Experiment (SPICE) scientific advances and future west pacific coordination</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganachaud, A. S.; Sprintall, J.; Lin, X.; Ando, K.</p> <p>2016-02-01</p> <p>The Southwest Pacific <span class="hlt">Ocean</span> Circulation and <span class="hlt">Climate</span> Experiment (SPICE) is an international research program under the auspices of CLIVAR (<span class="hlt">Climate</span> Variability and Predictability). The key objectives are to understand the Southwest Pacific <span class="hlt">Ocean</span> circulation and Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale <span class="hlt">climate</span> patterns. It was designed to measure and monitor the <span class="hlt">ocean</span> circulation, and to validate and improve numerical <span class="hlt">models</span>. South Pacific <span class="hlt">oceanic</span> waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern <span class="hlt">Ocean</span>. Water transit through the Coral and Solomon Seas is potentially of great importance to tropical <span class="hlt">climate</span> prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale <span class="hlt">climate</span> feedbacks. On average, the <span class="hlt">oceanic</span> circulation is driven by the Trade Winds, and subject to substantial variability, related with the SPCZ position and intensity. The circulation is complex, with the SEC splitting into zonal jets upon encountering island archipelagos, before joining either the East Australian Current or the New Guinea Costal UnderCurrent towards the equator. SPICE included large, coordinated in situ measurement programs and high resolution numerical simulations of the area. After 8 years of substantial in situ <span class="hlt">oceanic</span> observational and <span class="hlt">modeling</span> efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. We will review the recent advancements and discuss</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P54A1740K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P54A1740K"><span>Toward Dynamic <span class="hlt">Ocean</span> Management: Fisheries assessment and <span class="hlt">climate</span> projections informed by community developed habitat <span class="hlt">models</span> based on dynamic coastal oceanography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohut, J. T.; Manderson, J.; Palamara, L. J.; Saba, V. S.; Saba, G.; Hare, J. A.; Curchitser, E. N.; Moore, P.; Seibel, B.; DiDomenico, G.</p> <p>2016-12-01</p> <p>Through a multidisciplinary study group of experts in marine ecology, physical oceanography and stock assessment from the fishing industry, government and academia we developed a method to explicitly account for shifting habitat distributions in fish population assessments. We used data from field surveys throughout the Northwest Atlantic <span class="hlt">Ocean</span> to develop a parametric thermal niche <span class="hlt">model</span> for an important short-lived pelagic forage fish, Atlantic Butterfish. This niche <span class="hlt">model</span> was coupled to a hindcast of daily bottom water temperature derived from a regional numerical <span class="hlt">ocean</span> <span class="hlt">model</span> in order to project daily thermal habitat suitability over the last 40 years. This ecological hindcast was used to estimate the proportion of thermal habitat suitability available on the U.S. Northeast Shelf that was sampled on fishery-independent surveys, accounting for the relative motions of thermal habitat and the trajectory of sampling on the survey. The method and habitat based estimates of availability was integrated into the catchability estimate used to scale population size in the butterfish stock assessment <span class="hlt">model</span> accepted by the reviewers of the 59th NEFSC stock assessment review, as well as the mid-Atlantic Council's Scientific and Statistical Committee. The contribution of the availability estimate (along with an estimate of detectability) allowed for the development of fishery reference points, a change in stock status from unknown to known, and the establishment of a directed fishery with an allocation of 20,000 metric tons of quota. This presentation will describe how a community based workgroup utilized <span class="hlt">ocean</span> observing technologies combined with <span class="hlt">ocean</span> <span class="hlt">models</span> to better understand the physical <span class="hlt">ocean</span> that structures marine ecosystems. Using these approaches we will discuss opportunities to inform ecological hindcasts and <span class="hlt">climate</span> projections with mechanistic <span class="hlt">models</span> that link species-specific physiology to <span class="hlt">climate</span>-based thermal scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.P54A1740K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.P54A1740K"><span>Toward Dynamic <span class="hlt">Ocean</span> Management: Fisheries assessment and <span class="hlt">climate</span> projections informed by community developed habitat <span class="hlt">models</span> based on dynamic coastal oceanography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohut, J. T.; Manderson, J.; Palamara, L. J.; Saba, V. S.; Saba, G.; Hare, J. A.; Curchitser, E. N.; Moore, P.; Seibel, B.; DiDomenico, G.</p> <p>2016-02-01</p> <p>Through a multidisciplinary study group of experts in marine ecology, physical oceanography and stock assessment from the fishing industry, government and academia we developed a method to explicitly account for shifting habitat distributions in fish population assessments. We used data from field surveys throughout the Northwest Atlantic <span class="hlt">Ocean</span> to develop a parametric thermal niche <span class="hlt">model</span> for an important short-lived pelagic forage fish, Atlantic Butterfish. This niche <span class="hlt">model</span> was coupled to a hindcast of daily bottom water temperature derived from a regional numerical <span class="hlt">ocean</span> <span class="hlt">model</span> in order to project daily thermal habitat suitability over the last 40 years. This ecological hindcast was used to estimate the proportion of thermal habitat suitability available on the U.S. Northeast Shelf that was sampled on fishery-independent surveys, accounting for the relative motions of thermal habitat and the trajectory of sampling on the survey. The method and habitat based estimates of availability was integrated into the catchability estimate used to scale population size in the butterfish stock assessment <span class="hlt">model</span> accepted by the reviewers of the 59th NEFSC stock assessment review, as well as the mid-Atlantic Council's Scientific and Statistical Committee. The contribution of the availability estimate (along with an estimate of detectability) allowed for the development of fishery reference points, a change in stock status from unknown to known, and the establishment of a directed fishery with an allocation of 20,000 metric tons of quota. This presentation will describe how a community based workgroup utilized <span class="hlt">ocean</span> observing technologies combined with <span class="hlt">ocean</span> <span class="hlt">models</span> to better understand the physical <span class="hlt">ocean</span> that structures marine ecosystems. Using these approaches we will discuss opportunities to inform ecological hindcasts and <span class="hlt">climate</span> projections with mechanistic <span class="hlt">models</span> that link species-specific physiology to <span class="hlt">climate</span>-based thermal scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC41B0560K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC41B0560K"><span>Mitigating <span class="hlt">Climate</span> Change with <span class="hlt">Ocean</span> Pipes: Influencing Land Temperature and Hydrology and Termination Overshoot Risk</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwiatkowski, L.; Caldeira, K.; Ricke, K.</p> <p>2014-12-01</p> <p>With increasing risk of dangerous <span class="hlt">climate</span> change geoengineering solutions to Earth's <span class="hlt">climate</span> problems have attracted much attention. One proposed geoengineering approach considers the use of <span class="hlt">ocean</span> pipes as a means to increase <span class="hlt">ocean</span> carbon uptake and the storage of thermal energy in the deep <span class="hlt">ocean</span>. We use a latest generation Earth System <span class="hlt">Model</span> (ESM) to perform simulations of idealised extreme implementations of <span class="hlt">ocean</span> pipes. In our simulations, downward transport of thermal energy by <span class="hlt">ocean</span> pipes strongly cools the near surface atmosphere - by up to 11°C on a global mean. The <span class="hlt">ocean</span> pipes cause net thermal energy to be transported from the terrestrial environment to the deep <span class="hlt">ocean</span> while increasing the global net transport of water to land. By cooling the <span class="hlt">ocean</span> surface more than the land, <span class="hlt">ocean</span> pipes tend to promote a monsoonal-type circulation, resulting in increased water vapour transport to land. Throughout their implementation, <span class="hlt">ocean</span> pipes prevent energy from escaping to space, increasing the amount of energy stored in Earth's <span class="hlt">climate</span> system despite reductions in surface temperature. As a consequence, our results indicate that an abrupt termination of <span class="hlt">ocean</span> pipes could cause dramatic increases in surface temperatures beyond that which would have been obtained had <span class="hlt">ocean</span> pipes not been implemented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9186V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9186V"><span>The impact of Southern <span class="hlt">Ocean</span> gateways on the Cenozoic <span class="hlt">climate</span> evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>von der Heydt, Anna; Viebahn, Jan; Dijkstra, Henk</p> <p>2016-04-01</p> <p>During the Cenozoic period, which covers the last 65 Million (Ma) years, Earth's <span class="hlt">climate</span> has undergone a major long-term transition from warm "greenhouse" to colder "icehouse" conditions with extensive ice sheets in the polar regions of both hemispheres. On the very long term the gradual cooling may be seen as response to the overall slowly decreasing atmospheric CO2-concentration due to weathering processes in the Earth System, however, continental geometry has changed considerably over this period and the long-term gradual trend was interrupted, by several rapid transitions as well as periods where temperature and greenhouse gas concentrations seem to be decoupled. The Eocene-Oligocene boundary (˜34 Ma, E/O) and mid-Miocene <span class="hlt">climatic</span> transition (˜13 Ma, MCT) reflect major phases of Antarctic ice sheet build-up and global <span class="hlt">climate</span> cooling, while Northern Hemisphere ice sheets developed much later, most likely at the Pliocene-Pleistocene transition (˜2.7Ma). Thresholds in atmospheric CO2-concentration together with feedback mechanisms related to land ice formation are now among the favoured mechanisms of these <span class="hlt">climatic</span> transitions, while the long-proposed <span class="hlt">ocean</span> circulation changes caused by opening of tectonic gateways seem to play a less direct role. The opening of the Southern <span class="hlt">Ocean</span> gateways, notably the Drake Passage and the Tasman Gateway as well as the northward movement of Australia over this long time period, however, has eventually led to the development of today's strongest <span class="hlt">ocean</span> current, the Antarctic Circumpolar Current (ACC), playing a major role in the transport properties of the global <span class="hlt">ocean</span> circulation. The overall state of the global <span class="hlt">ocean</span> circulation, therefore, preconditions the <span class="hlt">climate</span> system to dramatic events such as major ice sheet formation. Here, we present results of a state-of-the art global <span class="hlt">climate</span> <span class="hlt">model</span> (CESM) under various continental configurations: (i) present day geometry, (ii) present day geometry with a closed Drake Passage and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015729','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015729"><span>Role of the <span class="hlt">ocean</span> in <span class="hlt">climate</span> changes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gulev, Sergey K.</p> <p>1992-01-01</p> <p>The present program aimed at the study of <span class="hlt">ocean</span> <span class="hlt">climate</span> change is prepared by a group of scientists from State Oceanographic Institute, Academy of Science of Russia, Academy of Science of Ukraine and Moscow State University. It appears to be a natural evolution of ideas and achievements that have been developed under national and international <span class="hlt">ocean</span> research projects such as SECTIONS, WOCE, TOGA, JGOFS and others. The two primary goals are set in the program ROCC. (1) Quantitative description of the global interoceanic 'conveyor' and it's role in formation of the large scale anomalies in the North Atlantic. The objectives on the way to this goal are: to get the reliable estimates of year-to-year variations of heat and water exchange between the Atlantic <span class="hlt">Ocean</span> and the atmosphere; to establish and understand the physics of long period variations in meridianal heat and fresh water transport (MHT and MFWT) in the Atlantic <span class="hlt">Ocean</span>; to analyze the general mechanisms, that form the MHT and MFWT in low latitudes (Ekman flux), middle latitudes (western boundary currents) and high latitudes (deep convection) of the North Atlantic; to establish and to give quantitative description of the realization of global changes in SST, surface salinity, sea level and sea ice data. (2) Development of the observational system pointed at tracing the <span class="hlt">climate</span> changes in the North Atlantic. This goal merges the following objectives: to find the proper sites that form the inter annual variations of MHT; to study the deep circulation in the 'key' points; to develop the circulation <span class="hlt">models</span> reflecting the principle features of interoceanic circulation; and to define global and local response of the atmosphere circulation to large scale processes in the Atlantic <span class="hlt">Ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...46.2403P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...46.2403P"><span>Tropical Indian <span class="hlt">Ocean</span> surface salinity bias in <span class="hlt">Climate</span> Forecasting System coupled <span class="hlt">models</span> and the role of upper <span class="hlt">ocean</span> processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parekh, Anant; Chowdary, Jasti S.; Sayantani, Ojha; Fousiya, T. S.; Gnanaseelan, C.</p> <p>2016-04-01</p> <p>In the present study sea surface salinity (SSS) biases and seasonal tendency over the Tropical Indian <span class="hlt">Ocean</span> (TIO) in the coupled <span class="hlt">models</span> [<span class="hlt">Climate</span> Forecasting System version 1 (CFSv1) and version 2 (CFSv2)] are examined with respect to observations. Both CFSv1 and CFSv2 overestimate SSS over the TIO throughout the year. CFSv1 displays improper SSS seasonal cycle over the Bay of Bengal (BoB), which is due to weaker <span class="hlt">model</span> precipitation and improper river runoff especially during summer and fall. Over the southeastern Arabian Sea (AS) weak horizontal advection associated with East Indian coastal current during winter limits the formation of spring fresh water pool. On the other hand, weaker Somali jet during summer results for reduced positive salt tendency in the central and eastern AS. Strong positive precipitation bias in CFSv1 over the region off Somalia during winter, weaker vertical mixing and absence of horizontal salt advection lead to unrealistic barrier layer during winter and spring. The weaker stratification and improper spatial distribution of barrier layer thickness (BLT) in CFSv1 indicate that not only horizontal flux distribution but also vertical salt distribution displays large discrepancies. Absence of fall Wyrtki jet and winter equatorial currents in this <span class="hlt">model</span> limit the advection of horizontal salt flux to the eastern equatorial Indian <span class="hlt">Ocean</span>. The associated weaker stratification in eastern equatorial Indian <span class="hlt">Ocean</span> can lead to deeper mixed layer and negative Sea Surface Temperature (SST) bias, which in turn favor positive Indian <span class="hlt">Ocean</span> Dipole bias in CFSv1. It is important to note that improper spatial distribution of barrier layer and stratification can alter the air-sea interaction and precipitation in the <span class="hlt">models</span>. On the other hand CFSv2 could produce the seasonal evolution and spatial distribution of SSS, BLT and stratification better than CFSv1. However CFSv2 displays positive bias in evaporation over the whole domain and negative bias in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME13A..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME13A..04L"><span>Potential Impact of North Atlantic <span class="hlt">Climate</span> Variability on <span class="hlt">Ocean</span> Biogeochemical Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Y.; Muhling, B.; Lee, S. K.; Muller-Karger, F. E.; Enfield, D. B.; Lamkin, J. T.; Roffer, M. A.</p> <p>2016-02-01</p> <p>Previous studies have shown that upper <span class="hlt">ocean</span> circulations largely determine primary production in the euphotic layers, here the global <span class="hlt">ocean</span> <span class="hlt">model</span> with biogeochemistry (GFDL's Modular <span class="hlt">Ocean</span> <span class="hlt">Model</span> with TOPAZ biogeochemistry) forced with the ERA-Interim is used to simulate the natural variability of biogeochemical processes in global <span class="hlt">ocean</span> during 1979-present. Preliminary results show that the surface chlorophyll is overall underestimated in MOM-TOPAZ, but its spatial pattern is fairly realistic. Relatively high chlorophyll variability is shown in the subpolar North Atlantic, northeastern tropical Atlantic, and equatorial Atlantic. Further analysis suggests that the chlorophyll variability in the North Atlantic <span class="hlt">Ocean</span> is affected by long-term <span class="hlt">climate</span> variability. For the subpolar North Atlantic region, the chlorophyll variability is light-limited and is significantly correlated with North Atlantic Oscillation. A dipole pattern of chlorophyll variability is found between the northeastern tropical Atlantic and equatorial Atlantic. For the northeastern North Atlantic, the chlorophyll variability is significantly correlated with Atlantic Meridional Mode (AMM) and Atlantic Multidecadal Oscillation (AMO). During the negative phase of AMM and AMO, the increased trade wind in the northeast North Atlantic can lead to increased upwelling of nutrients. In the equatorial Atlantic region, the chlorophyll variability is largely link to Atlantic-Niño and associated equatorial upwelling of nutrients. The potential impact of <span class="hlt">climate</span> variability on the distribution of pelagic fishes (i.e. yellowfin tuna) are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040090095&hterms=Eocene&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEocene','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040090095&hterms=Eocene&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEocene"><span>Possible role of <span class="hlt">oceanic</span> heat transport in early Eocene <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sloan, L. C.; Walker, J. C.; Moore, T. C. Jr</p> <p>1995-01-01</p> <p>Increased <span class="hlt">oceanic</span> heat transport has often been cited as a means of maintaining warm high-latitude surface temperatures in many intervals of the geologic past, including the early Eocene. Although the excess amount of <span class="hlt">oceanic</span> heat transport required by warm high latitude sea surface temperatures can be calculated empirically, determining how additional <span class="hlt">oceanic</span> heat transport would take place has yet to be accomplished. That the mechanisms of enhanced poleward <span class="hlt">oceanic</span> heat transport remain undefined in paleoclimate reconstructions is an important point that is often overlooked. Using early Eocene <span class="hlt">climate</span> as an example, we consider various ways to produce enhanced poleward heat transport and latitudinal energy redistribution of the sign and magnitude required by interpreted early Eocene conditions. Our interpolation of early Eocene paleotemperature data indicate that an approximately 30% increase in poleward heat transport would be required to maintain Eocene high-latitude temperatures. This increased heat transport appears difficult to accomplish by any means of <span class="hlt">ocean</span> circulation if we use present <span class="hlt">ocean</span> circulation characteristics to evaluate early Eocene rates. Either <span class="hlt">oceanic</span> processes were very different from those of the present to produce the early Eocene <span class="hlt">climate</span> conditions or <span class="hlt">oceanic</span> heat transport was not the primary cause of that <span class="hlt">climate</span>. We believe that atmospheric processes, with contributions from other factors, such as clouds, were the most likely primary cause of early Eocene <span class="hlt">climate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9632385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9632385"><span>The influence of vegetation-atmosphere-<span class="hlt">ocean</span> interaction on <span class="hlt">climate</span> during the mid-holocene</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ganopolski; Kubatzki; Claussen; Brovkin; Petoukhov</p> <p>1998-06-19</p> <p>Simulations with a synchronously coupled atmosphere-<span class="hlt">ocean</span>-vegetation <span class="hlt">model</span> show that changes in vegetation cover during the mid-Holocene, some 6000 years ago, modify and amplify the <span class="hlt">climate</span> system response to an enhanced seasonal cycle of solar insolation in the Northern Hemisphere both directly (primarily through the changes in surface albedo) and indirectly (through changes in <span class="hlt">oceanic</span> temperature, sea-ice cover, and <span class="hlt">oceanic</span> circulation). The <span class="hlt">model</span> results indicate strong synergistic effects of changes in vegetation cover, <span class="hlt">ocean</span> temperature, and sea ice at boreal latitudes, but in the subtropics, the atmosphere-vegetation feedback is most important. Moreover, a reduction of the thermohaline circulation in the Atlantic <span class="hlt">Ocean</span> leads to a warming of the Southern Hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Chaos..27l6704S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Chaos..27l6704S"><span>Role of atmosphere-<span class="hlt">ocean</span> interactions in supermodeling the tropical Pacific <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Mao-Lin; Keenlyside, Noel; Bhatt, Bhuwan C.; Duane, Gregory S.</p> <p>2017-12-01</p> <p>The supermodel strategy interactively combines several <span class="hlt">models</span> to outperform the individual <span class="hlt">models</span> comprising it. A key advantage of the approach is that nonlinear improvements can be achieved, in contrast to the linear weighted combination of individual unconnected <span class="hlt">models</span>. This property is found in a <span class="hlt">climate</span> supermodel constructed by coupling two versions of an atmospheric <span class="hlt">model</span> differing only in their convection scheme to a single <span class="hlt">ocean</span> <span class="hlt">model</span>. The <span class="hlt">ocean</span> <span class="hlt">model</span> receives a weighted combination of the momentum and heat fluxes. Optimal weights can produce a supermodel with a basic state similar to observations: a single Intertropical Convergence zone (ITCZ), with a western Pacific warm pool and an equatorial cold tongue. This is in stark contrast to the erroneous double ITCZ pattern simulated by both of the two stand-alone coupled <span class="hlt">models</span>. By varying weights, we develop a conceptual scheme to explain how combining the momentum fluxes of the two different atmospheric <span class="hlt">models</span> affects equatorial upwelling and surface wind feedback so as to give a realistic basic state in the tropical Pacific. In particular, we propose a mechanism based on the competing influences of equatorial zonal wind and off-equatorial wind stress curl in driving equatorial upwelling in the coupled <span class="hlt">models</span>. Our results show how nonlinear <span class="hlt">ocean</span>-atmosphere interaction is essential in combining these two effects to build different sea surface temperature structures, some of which are realistic. They also provide some insight into observed and <span class="hlt">modelled</span> tropical Pacific <span class="hlt">climate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29289039','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29289039"><span>Role of atmosphere-<span class="hlt">ocean</span> interactions in supermodeling the tropical Pacific <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shen, Mao-Lin; Keenlyside, Noel; Bhatt, Bhuwan C; Duane, Gregory S</p> <p>2017-12-01</p> <p>The supermodel strategy interactively combines several <span class="hlt">models</span> to outperform the individual <span class="hlt">models</span> comprising it. A key advantage of the approach is that nonlinear improvements can be achieved, in contrast to the linear weighted combination of individual unconnected <span class="hlt">models</span>. This property is found in a <span class="hlt">climate</span> supermodel constructed by coupling two versions of an atmospheric <span class="hlt">model</span> differing only in their convection scheme to a single <span class="hlt">ocean</span> <span class="hlt">model</span>. The <span class="hlt">ocean</span> <span class="hlt">model</span> receives a weighted combination of the momentum and heat fluxes. Optimal weights can produce a supermodel with a basic state similar to observations: a single Intertropical Convergence zone (ITCZ), with a western Pacific warm pool and an equatorial cold tongue. This is in stark contrast to the erroneous double ITCZ pattern simulated by both of the two stand-alone coupled <span class="hlt">models</span>. By varying weights, we develop a conceptual scheme to explain how combining the momentum fluxes of the two different atmospheric <span class="hlt">models</span> affects equatorial upwelling and surface wind feedback so as to give a realistic basic state in the tropical Pacific. In particular, we propose a mechanism based on the competing influences of equatorial zonal wind and off-equatorial wind stress curl in driving equatorial upwelling in the coupled <span class="hlt">models</span>. Our results show how nonlinear <span class="hlt">ocean</span>-atmosphere interaction is essential in combining these two effects to build different sea surface temperature structures, some of which are realistic. They also provide some insight into observed and <span class="hlt">modelled</span> tropical Pacific <span class="hlt">climate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018OcMod.122...57G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018OcMod.122...57G"><span>A commentary on the Atlantic meridional overturning circulation stability in <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gent, Peter R.</p> <p>2018-02-01</p> <p>The stability of the Atlantic meridional overturning circulation (AMOC) in <span class="hlt">ocean</span> <span class="hlt">models</span> depends quite strongly on the <span class="hlt">model</span> formulation, especially the vertical mixing, and whether it is coupled to an atmosphere <span class="hlt">model</span>. A hysteresis loop in AMOC strength with respect to freshwater forcing has been found in several intermediate complexity <span class="hlt">climate</span> <span class="hlt">models</span> and in one fully coupled <span class="hlt">climate</span> <span class="hlt">model</span> that has very coarse resolution. Over 40% of modern <span class="hlt">climate</span> <span class="hlt">models</span> are in a bistable AMOC state according to the very frequently used simple stability criterion which is based solely on the sign of the AMOC freshwater transport across 33° S. In a recent freshwater hosing experiment in a <span class="hlt">climate</span> <span class="hlt">model</span> with an eddy-permitting <span class="hlt">ocean</span> component, the change in the gyre freshwater transport across 33° S is larger than the AMOC freshwater transport change. This casts very strong doubt on the usefulness of this simple AMOC stability criterion. If a <span class="hlt">climate</span> <span class="hlt">model</span> uses large surface flux adjustments, then these adjustments can interfere with the atmosphere-<span class="hlt">ocean</span> feedbacks, and strongly change the AMOC stability properties. AMOC can be shut off for many hundreds of years in modern fully coupled <span class="hlt">climate</span> <span class="hlt">models</span> if the hosing or carbon dioxide forcing is strong enough. However, in one <span class="hlt">climate</span> <span class="hlt">model</span> the AMOC recovers after between 1000 and 1400 years. Recent 1% increasing carbon dioxide runs and RCP8.5 future scenario runs have shown that the AMOC reduction is smaller using an eddy-resolving <span class="hlt">ocean</span> component than in the comparable standard 1° <span class="hlt">ocean</span> <span class="hlt">climate</span> <span class="hlt">models</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1418778','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1418778"><span>A simple <span class="hlt">model</span> of the effect of <span class="hlt">ocean</span> ventilation on <span class="hlt">ocean</span> heat uptake</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nadiga, Balasubramanya T.; Urban, Nathan Mark</p> <p></p> <p>Presentation includes slides on Earth System <span class="hlt">Models</span> vs. Simple <span class="hlt">Climate</span> <span class="hlt">Models</span>; A Popular SCM: Energy Balance <span class="hlt">Model</span> of Anomalies; On calibrating against one ESM experiment, the SCM correctly captures that ESM's surface warming response with other forcings; Multi-<span class="hlt">Model</span> Analysis: Multiple ESMs, Single SCM; Posterior Distributions of ECS; However In Excess of 90% of TOA Energy Imbalance is Sequestered in the World <span class="hlt">Oceans</span>; Heat Storage in the Two Layer <span class="hlt">Model</span>; Heat Storage in the Two Layer <span class="hlt">Model</span>; Including TOA Rad. Imbalance and <span class="hlt">Ocean</span> Heat in Calibration Improves Repr., but Significant Errors Persist; Improved Vertical Resolution Does Not Fix Problem; A Seriesmore » of Expts. Confirms That Anomaly-Diffusing <span class="hlt">Models</span> Cannot Properly Represent <span class="hlt">Ocean</span> Heat Uptake; Physics of the Thermocline; Outcropping Isopycnals and Horizontally-Averaged Layers; Local interactions between outcropping isopycnals leads to non-local interactions between horizontally-averaged layers; Both Surface Warming and <span class="hlt">Ocean</span> Heat are Well Represented With Just 4 Layers; A Series of Expts. Confirms That When Non-Local Interactions are Allowed, the SCMs Can Represent Both Surface Warming and <span class="hlt">Ocean</span> Heat Uptake; and Summary and Conclusions.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMIN41D..07A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMIN41D..07A"><span>A Virtual <span class="hlt">Ocean</span> Observatory for <span class="hlt">Climate</span> and <span class="hlt">Ocean</span> Science: Synergistic Applications for SWOT and XOVWM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arabshahi, P.; Howe, B. M.; Chao, Y.; Businger, S.; Chien, S.</p> <p>2010-12-01</p> <p>We present a virtual <span class="hlt">ocean</span> observatory (VOO) that supports <span class="hlt">climate</span> and <span class="hlt">ocean</span> science as addressed in the NRC decadal survey. The VOO is composed of an autonomous software system, in-situ and space-based sensing assets, data sets, and interfaces to <span class="hlt">ocean</span> and atmosphere <span class="hlt">models</span>. The purpose of this observatory and its output data products are: 1) to support SWOT mission planning, 2) to serve as a vanguard for fusing SWOT, XOVWM, and in-situ data sets through fusion of OSTM (SWOT proxy) and QuikSCAT (XOVWM proxy) data with in-situ data, and 3) to serve as a feed-forward platform for high-resolution measurements of <span class="hlt">ocean</span> surface topography (OST) in island and coastal environments utilizing space-based and in-situ adaptive sampling. The VOO will enable <span class="hlt">models</span> capable of simulating and estimating realistic <span class="hlt">oceanic</span> processes and atmospheric forcing of the <span class="hlt">ocean</span> in these environments. Such measurements are critical in understanding the <span class="hlt">oceans</span>' effects on global <span class="hlt">climate</span>. The information systems innovations of the VOO are: 1. Development of an autonomous software platform for automated mission planning and combining science data products of QuikSCAT and OSTM with complementary in-situ data sets to deliver new data products. This software will present first-step demonstrations of technology that, once matured, will offer increased operational capability to SWOT by providing automated planning, and new science data sets using automated workflows. The future data sets to be integrated include those from SWOT and XOVWM. 2. A capstone demonstration of the effort utilizes the elements developed in (1) above to achieve adaptive in-situ sampling through feedback from space-based-assets via the SWOT simulator. This effort will directly contribute to orbit design during the experimental phase (first 6-9 months) of the SWOT mission by high resolution regional atmospheric and <span class="hlt">ocean</span> <span class="hlt">modeling</span> and sampling. It will also contribute to SWOT science via integration of in-situ data, Quik</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20840607','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20840607"><span>Contrasted demographic responses facing future <span class="hlt">climate</span> change in Southern <span class="hlt">Ocean</span> seabirds.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barbraud, Christophe; Rivalan, Philippe; Inchausti, Pablo; Nevoux, Marie; Rolland, Virginie; Weimerskirch, Henri</p> <p>2011-01-01</p> <p>1. Recent <span class="hlt">climate</span> change has affected a wide range of species, but predicting population responses to projected <span class="hlt">climate</span> change using population dynamics theory and <span class="hlt">models</span> remains challenging, and very few attempts have been made. The Southern <span class="hlt">Ocean</span> sea surface temperature and sea ice extent are projected to warm and shrink as concentrations of atmospheric greenhouse gases increase, and several top predator species are affected by fluctuations in these oceanographic variables. 2. We compared and projected the population responses of three seabird species living in sub-tropical, sub-Antarctic and Antarctic biomes to predicted <span class="hlt">climate</span> change over the next 50 years. Using stochastic population <span class="hlt">models</span> we combined long-term demographic datasets and projections of sea surface temperature and sea ice extent for three different IPCC emission scenarios (from most to least severe: A1B, A2, B1) from general circulation <span class="hlt">models</span> of Earth's <span class="hlt">climate</span>. 3. We found that <span class="hlt">climate</span> mostly affected the probability to breed successfully, and in one case adult survival. Interestingly, frequent nonlinear relationships in demographic responses to <span class="hlt">climate</span> were detected. <span class="hlt">Models</span> forced by future predicted <span class="hlt">climatic</span> change provided contrasted population responses depending on the species considered. The northernmost distributed species was predicted to be little affected by a future warming of the Southern <span class="hlt">Ocean</span>, whereas steep declines were projected for the more southerly distributed species due to sea surface temperature warming and decrease in sea ice extent. For the most southerly distributed species, the A1B and B1 emission scenarios were respectively the most and less damaging. For the two other species, population responses were similar for all emission scenarios. 4. This is among the first attempts to study the demographic responses for several populations with contrasted environmental conditions, which illustrates that investigating the effects of <span class="hlt">climate</span> change on core population dynamics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP41B1296L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP41B1296L"><span><span class="hlt">Climate</span> and <span class="hlt">Ocean</span> Circulation During "The Boring Billion" Simulated by CCSM3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, P.; Hu, Y.; Liu, Y.</p> <p>2017-12-01</p> <p>The Boring Billion is referred to the era between approximately 1.8 and 0.8 billion years ago. Geological evidence suggests that no dramatic <span class="hlt">climate</span> changes in the billions of years, at least in terms of permanent glaciation. The atmospheric oxygen maintained at a relatively low level without significant perturbations. Life had a certain degree of evolution with a quite gentle pace. Relative to the Great Oxidation Event occurred previously, and the Snowball Earth Event and Cambrian Explosion occurred afterwards, this billion years was calm in all aspects so it's often referred to as "the Boring Billion". Why were both the <span class="hlt">climate</span> and oxygen concentration so stable, and how the anoxic condition in the deep <span class="hlt">ocean</span> maintained are the questions that motivated our research. We use the Atmosphere <span class="hlt">Ocean</span> General Circulation <span class="hlt">Model</span> CCSM3 in this study. The <span class="hlt">climate</span> of the Boring Billion is simulated for two distinct continental configurations reconstructed for 1540 Ma and 1420 Ma, with continental fragments concentrating towards the North Pole and equator, respectively. The solar constant is set to be 10% weaker than that of the present day. The results show that when the concentration of CO2 is 20 times the present atmospheric level (PAL), the global mean surface temperatures are 19 ° C and 20 ° C for the 1540 Ma and 1420 Ma continental configuration, respectively. Large scale permanent glaciers cannot develop in such a warm <span class="hlt">climate</span> even for the continents at the polar region. The largest mixed-layer depth in the high-latitude <span class="hlt">ocean</span> is approximately 1200 m and meridional overturning circulation can reach depth of 3000 m with strength of 40 Sv for both continental configuration. This implies that the material and energy exchange between shallow and deep <span class="hlt">ocean</span>, as well as atmosphere and <span class="hlt">ocean</span>, is efficient. When CO2 concentration is reduced to 10 PAL, 5 PAL or 2.5 PAL, global average temperature becomes 16 ° C, 13 ° C and 2 ° C respectively, and permanent glaciers start to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1690J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1690J"><span>Antarctic <span class="hlt">Climate</span> Variability: Covariance of Ozone and Sea Ice in Atmosphere - <span class="hlt">Ocean</span> Coupled <span class="hlt">Model</span> Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jrrar, Amna; Abraham, N. Luke; Pyle, John A.; Holland, David</p> <p>2014-05-01</p> <p>Changes in sea ice significantly modulate <span class="hlt">climate</span> change because of its high reflective and insulating nature. While Arctic Sea Ice Extent (SIE) shows a negative trend. Antarctic SIE shows a weak but positive trend, estimated at 0.127 x 106 km2 per decade. The trend results from large regional cancellations, more ice in the Weddell and the Ross seas, and less ice in the Amundsen - Bellingshausen seas. A number of studies had demonstrated that stratospheric ozone depletion has had a major impact on the atmospheric circulation, causing a positive trend in the Southern Annular Mode (SAM), which has been linked to the observed positive trend in autumn sea ice in the Ross Sea. However, other <span class="hlt">modelling</span> studies show that <span class="hlt">models</span> forced with prescribed ozone hole simulate decreased sea ice in all regions comparative to a control run. A recent study has also shown that stratospheric ozone recovery will mitigate Antarctic sea ice loss. To verify this assumed relationship, it is important first to investigate the covariance between ozone's natural (dynamical) variability and Antarctic sea ice distribution in pre-industrial <span class="hlt">climate</span>, to estimate the trend due to natural variability. We investigate the relationship between anomalous Antarctic ozone years and the subsequent changes in Antarctic sea ice distribution in a multidecadal control simulation using the AO-UMUKCA <span class="hlt">model</span>. The <span class="hlt">model</span> has a horizontal resolution of 3.75 X 2.5 degrees in longitude and latitude; and 60 hybrid height levels in the vertical, from the surface up to a height of 84 km. The <span class="hlt">ocean</span> component is the NEMO <span class="hlt">ocean</span> <span class="hlt">model</span> on the ORCA2 tripolar grid, and the sea ice <span class="hlt">model</span> is CICE. We evaluate the <span class="hlt">model</span>'s performance in terms of sea ice distribution, and we calculate sea ice extent trends for composites of anomalously low versus anomalously high SH polar ozone column. We apply EOF analysis to the seasonal anomalies of sea ice concentration, MSLP, and Z 500, and identify the leading <span class="hlt">climate</span> modes controlling the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28054561','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28054561"><span>Pliocene <span class="hlt">oceanic</span> seaways and global <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Karas, Cyrus; Nürnberg, Dirk; Bahr, André; Groeneveld, Jeroen; Herrle, Jens O; Tiedemann, Ralf; deMenocal, Peter B</p> <p>2017-01-05</p> <p>Tectonically induced changes in <span class="hlt">oceanic</span> seaways had profound effects on global and regional <span class="hlt">climate</span> during the Late Neogene. The constriction of the Central American Seaway reached a critical threshold during the early Pliocene ~4.8-4 million years (Ma) ago. <span class="hlt">Model</span> simulations indicate the strengthening of the Atlantic Meridional Overturning Circulation (AMOC) with a signature warming response in the Northern Hemisphere and cooling in the Southern Hemisphere. Subsequently, between ~4-3 Ma, the constriction of the Indonesian Seaway impacted regional <span class="hlt">climate</span> and might have accelerated the Northern Hemisphere Glaciation. We here present Pliocene Atlantic interhemispheric sea surface temperature and salinity gradients (deduced from foraminiferal Mg/Ca and stable oxygen isotopes, δ 18 O) in combination with a recently published benthic stable carbon isotope (δ 13 C) record from the southernmost extent of North Atlantic Deep Water to reconstruct gateway-related changes in the AMOC mode. After an early reduction of the AMOC at ~5.3 Ma, we show in agreement with <span class="hlt">model</span> simulations of the impacts of Central American Seaway closure a strengthened AMOC with a global <span class="hlt">climate</span> signature. During ~3.8-3 Ma, we suggest a weakening of the AMOC in line with the global cooling trend, with possible contributions from the constriction of the Indonesian Seaway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711176C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711176C"><span>A <span class="hlt">climate</span>-based multivariate extreme emulator of met-<span class="hlt">ocean</span>-hydrological events for coastal flooding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Camus, Paula; Rueda, Ana; Mendez, Fernando J.; Tomas, Antonio; Del Jesus, Manuel; Losada, Iñigo J.</p> <p>2015-04-01</p> <p>Atmosphere-<span class="hlt">ocean</span> general circulation <span class="hlt">models</span> (AOGCMs) are useful to analyze large-scale <span class="hlt">climate</span> variability (long-term historical periods, future <span class="hlt">climate</span> projections). However, applications such as coastal flood <span class="hlt">modeling</span> require <span class="hlt">climate</span> information at finer scale. Besides, flooding events depend on multiple <span class="hlt">climate</span> conditions: waves, surge levels from the open-<span class="hlt">ocean</span> and river discharge caused by precipitation. Therefore, a multivariate statistical downscaling approach is adopted to reproduce relationships between variables and due to its low computational cost. The proposed method can be considered as a hybrid approach which combines a probabilistic weather type downscaling <span class="hlt">model</span> with a stochastic weather generator component. Predictand distributions are reproduced <span class="hlt">modeling</span> the relationship with AOGCM predictors based on a physical division in weather types (Camus et al., 2012). The multivariate dependence structure of the predictand (extreme events) is introduced linking the independent marginal distributions of the variables by a probabilistic copula regression (Ben Ayala et al., 2014). This hybrid approach is applied for the downscaling of AOGCM data to daily precipitation and maximum significant wave height and storm-surge in different locations along the Spanish coast. Reanalysis data is used to assess the proposed method. A commonly predictor for the three variables involved is classified using a regression-guided clustering algorithm. The most appropriate statistical <span class="hlt">model</span> (general extreme value distribution, pareto distribution) for daily conditions is fitted. Stochastic simulation of the present <span class="hlt">climate</span> is performed obtaining the set of hydraulic boundary conditions needed for high resolution coastal flood <span class="hlt">modeling</span>. References: Camus, P., Menéndez, M., Méndez, F.J., Izaguirre, C., Espejo, A., Cánovas, V., Pérez, J., Rueda, A., Losada, I.J., Medina, R. (2014b). A weather-type statistical downscaling framework for <span class="hlt">ocean</span> wave <span class="hlt">climate</span>. Journal of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A14C..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A14C..05M"><span><span class="hlt">Ocean</span>-Atmosphere Coupling Processes Affecting Predictability in the <span class="hlt">Climate</span> System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, A. J.; Subramanian, A. C.; Seo, H.; Eliashiv, J. D.</p> <p>2017-12-01</p> <p>Predictions of the <span class="hlt">ocean</span> and atmosphere are often sensitive to coupling at the air-sea interface in ways that depend on the temporal and spatial scales of the target fields. We will discuss several aspects of these types of coupled interactions including <span class="hlt">oceanic</span> and atmospheric forecast applications. For <span class="hlt">oceanic</span> mesoscale eddies, the coupling can influence the energetics of the <span class="hlt">oceanic</span> flow itself. For Madden-Julian Oscillation onset, the coupling timestep should resolve the diurnal cycle to properly raise time-mean SST and latent heat flux prior to deep convection. For Atmospheric River events, the evolving SST field can alter the trajectory and intensity of precipitation anomalies along the California coast. Improvements in predictions will also rely on identifying and alleviating sources of biases in the <span class="hlt">climate</span> states of the coupled system. Surprisingly, forecast skill can also be improved by enhancing stochastic variability in the atmospheric component of coupled <span class="hlt">models</span> as found in a multiscale ensemble <span class="hlt">modeling</span> approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..897G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..897G"><span>The impacts of <span class="hlt">oceanic</span> deep temperature perturbations in the North Atlantic on decadal <span class="hlt">climate</span> variability and predictability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Germe, Agathe; Sévellec, Florian; Mignot, Juliette; Fedorov, Alexey; Nguyen, Sébastien; Swingedouw, Didier</p> <p>2017-12-01</p> <p>Decadal <span class="hlt">climate</span> predictability in the North Atlantic is largely related to <span class="hlt">ocean</span> low frequency variability, whose sensitivity to initial conditions is not very well understood. Recently, three-dimensional <span class="hlt">oceanic</span> temperature anomalies optimally perturbing the North Atlantic Mean Temperature (NAMT) have been computed via an optimization procedure using a linear adjoint to a realistic <span class="hlt">ocean</span> general circulation <span class="hlt">model</span>. The spatial pattern of the identified perturbations, localized in the North Atlantic, has the largest magnitude between 1000 and 4000 m depth. In the present study, the impacts of these perturbations on NAMT, on the Atlantic meridional overturning circulation (AMOC), and on <span class="hlt">climate</span> in general are investigated in a global coupled <span class="hlt">model</span> that uses the same <span class="hlt">ocean</span> <span class="hlt">model</span> as was used to compute the three-dimensional optimal perturbations. In the coupled <span class="hlt">model</span>, these perturbations induce AMOC and NAMT anomalies peaking after 5 and 10 years, respectively, generally consistent with the <span class="hlt">ocean</span>-only linear predictions. To further understand their impact, their magnitude was varied in a broad range. For initial perturbations with a magnitude comparable to the internal variability of the coupled <span class="hlt">model</span>, the <span class="hlt">model</span> response exhibits a strong signature in sea surface temperature and precipitation over North America and the Sahel region. The existence and impacts of these <span class="hlt">ocean</span> perturbations have important implications for decadal prediction: they can be seen either as a source of predictability or uncertainty, depending on whether the current observing system can detect them or not. In fact, comparing the magnitude of the imposed perturbations with the uncertainty of available <span class="hlt">ocean</span> observations such as Argo data or <span class="hlt">ocean</span> state estimates suggests that only the largest perturbations used in this study could be detectable. This highlights the importance for decadal <span class="hlt">climate</span> prediction of accurate <span class="hlt">ocean</span> density initialisation in the North Atlantic at intermediate and greater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002Natur.419..207R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002Natur.419..207R"><span><span class="hlt">Ocean</span> circulation and <span class="hlt">climate</span> during the past 120,000 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rahmstorf, Stefan</p> <p>2002-09-01</p> <p><span class="hlt">Oceans</span> cover more than two-thirds of our blue planet. The waters move in a global circulation system, driven by subtle density differences and transporting huge amounts of heat. <span class="hlt">Ocean</span> circulation is thus an active and highly nonlinear player in the global <span class="hlt">climate</span> game. Increasingly clear evidence implicates <span class="hlt">ocean</span> circulation in abrupt and dramatic <span class="hlt">climate</span> shifts, such as sudden temperature changes in Greenland on the order of 5-10 °C and massive surges of icebergs into the North Atlantic <span class="hlt">Ocean</span> - events that have occurred repeatedly during the last glacial cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17151666','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17151666"><span><span class="hlt">Climate</span>-driven trends in contemporary <span class="hlt">ocean</span> productivity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Behrenfeld, Michael J; O'Malley, Robert T; Siegel, David A; McClain, Charles R; Sarmiento, Jorge L; Feldman, Gene C; Milligan, Allen J; Falkowski, Paul G; Letelier, Ricardo M; Boss, Emmanuel S</p> <p>2006-12-07</p> <p>Contributing roughly half of the biosphere's net primary production (NPP), photosynthesis by <span class="hlt">oceanic</span> phytoplankton is a vital link in the cycling of carbon between living and inorganic stocks. Each day, more than a hundred million tons of carbon in the form of CO2 are fixed into organic material by these ubiquitous, microscopic plants of the upper <span class="hlt">ocean</span>, and each day a similar amount of organic carbon is transferred into marine ecosystems by sinking and grazing. The distribution of phytoplankton biomass and NPP is defined by the availability of light and nutrients (nitrogen, phosphate, iron). These growth-limiting factors are in turn regulated by physical processes of <span class="hlt">ocean</span> circulation, mixed-layer dynamics, upwelling, atmospheric dust deposition, and the solar cycle. Satellite measurements of <span class="hlt">ocean</span> colour provide a means of quantifying <span class="hlt">ocean</span> productivity on a global scale and linking its variability to environmental factors. Here we describe global <span class="hlt">ocean</span> NPP changes detected from space over the past decade. The period is dominated by an initial increase in NPP of 1,930 teragrams of carbon a year (Tg C yr(-1)), followed by a prolonged decrease averaging 190 Tg C yr(-1). These trends are driven by changes occurring in the expansive stratified low-latitude <span class="hlt">oceans</span> and are tightly coupled to coincident <span class="hlt">climate</span> variability. This link between the physical environment and <span class="hlt">ocean</span> biology functions through changes in upper-<span class="hlt">ocean</span> temperature and stratification, which influence the availability of nutrients for phytoplankton growth. The observed reductions in <span class="hlt">ocean</span> productivity during the recent post-1999 warming period provide insight on how future <span class="hlt">climate</span> change can alter marine food webs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6369M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6369M"><span>Splitting turbulence algorithm for mixing parameterization embedded in the <span class="hlt">ocean</span> <span class="hlt">climate</span> <span class="hlt">model</span>. Examples of data assimilation and Prandtl number variations.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moshonkin, Sergey; Gusev, Anatoly; Zalesny, Vladimir; Diansky, Nikolay</p> <p>2017-04-01</p> <p>Series of experiments were performed with a three-dimensional, free surface, sigma coordinate eddy-permitting <span class="hlt">ocean</span> circulation <span class="hlt">model</span> for Atlantic (from 30°S) - Arctic and Bering sea domain (0.25 degrees resolution, Institute of Numerical Mathematics <span class="hlt">Ocean</span> <span class="hlt">Model</span> or INMOM) using vertical grid refinement in the zone of fully developed turbulence (40 sigma-levels). The <span class="hlt">model</span> variables are horizontal velocity components, potential temperature, and salinity as well as free surface height. For parameterization of viscosity and diffusivity, the original splitting turbulence algorithm (STA) is used when total evolutionary equations for the turbulence kinetic energy (TKE) and turbulence dissipation frequency (TDF) split into the stages of transport-diffusion and generation-dissipation. For the generation-dissipation stage the analytical solution was obtained for TKE and TDF as functions of the buoyancy and velocity shift frequencies (BF and VSF). The proposed <span class="hlt">model</span> with STA is similar to the contemporary differential turbulence <span class="hlt">models</span>, concerning the physical formulations. At the same time, its algorithm has high enough computational efficiency. For mixing simulation in the zone of turbulence decay, the two kind numerical experiments were carried out, as with assimilation of annual mean <span class="hlt">climatic</span> buoyancy frequency, as with variation of Prandtl number function dependence upon the BF, VSF, TKE and TDF. The CORE-II data for 1948-2009 were used for experiments. Quality of temperature T and salinity S structure simulation is estimated by the comparison of <span class="hlt">model</span> monthly profiles T and S averaged for 1980-2009, with T and S monthly data from the World <span class="hlt">Ocean</span> Atlas 2013. Form of coefficients in equations for TKE and TDF on the generation-dissipation stage makes it possible to assimilate annual mean <span class="hlt">climatic</span> buoyancy frequency in a varying degree that cardinally improves adequacy of <span class="hlt">model</span> results to <span class="hlt">climatic</span> data in all analyzed <span class="hlt">model</span> domain. The numerical experiments with modified</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC51C0823R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC51C0823R"><span>Observationally-based Metrics of <span class="hlt">Ocean</span> Carbon and Biogeochemical Variables are Essential for Evaluating Earth System <span class="hlt">Model</span> Projections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, J. L.; Sarmiento, J. L.</p> <p>2017-12-01</p> <p>The Southern <span class="hlt">Ocean</span> is central to the <span class="hlt">climate</span>'s response to increasing levels of atmospheric greenhouse gases as it ventilates a large fraction of the global <span class="hlt">ocean</span> volume. Global coupled <span class="hlt">climate</span> <span class="hlt">models</span> and earth system <span class="hlt">models</span>, however, vary widely in their simulations of the Southern <span class="hlt">Ocean</span> and its role in, and response to, the ongoing anthropogenic forcing. Due to its complex water-mass structure and dynamics, Southern <span class="hlt">Ocean</span> carbon and heat uptake depend on a combination of winds, eddies, mixing, buoyancy fluxes and topography. Understanding how the <span class="hlt">ocean</span> carries heat and carbon into its interior and how the observed wind changes are affecting this uptake is essential to accurately projecting transient <span class="hlt">climate</span> sensitivity. Observationally-based metrics are critical for discerning processes and mechanisms, and for validating and comparing <span class="hlt">climate</span> <span class="hlt">models</span>. As the community shifts toward Earth system <span class="hlt">models</span> with explicit carbon simulations, more direct observations of important biogeochemical parameters, like those obtained from the biogeochemically-sensored floats that are part of the Southern <span class="hlt">Ocean</span> Carbon and <span class="hlt">Climate</span> Observations and <span class="hlt">Modeling</span> project, are essential. One goal of future observing systems should be to create observationally-based benchmarks that will lead to reducing uncertainties in <span class="hlt">climate</span> projections, and especially uncertainties related to <span class="hlt">oceanic</span> heat and carbon uptake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999ClDy...15..895C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999ClDy...15..895C"><span>Unstable behaviour of an upper <span class="hlt">ocean</span>-atmosphere coupled <span class="hlt">model</span>: role of atmospheric radiative processes and <span class="hlt">oceanic</span> heat transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen-Solal, E.; Le Treut, H.</p> <p></p> <p>We describe the initial bias of the <span class="hlt">climate</span> simulated by a coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">model</span>. The atmospheric component is a state-of-the-art atmospheric general circulation <span class="hlt">model</span>, whereas the <span class="hlt">ocean</span> component is limited to the upper <span class="hlt">ocean</span> and includes a mixed layer whose depth is computed by the <span class="hlt">model</span>. As the full <span class="hlt">ocean</span> general circulation is not computed by the <span class="hlt">model</span>, the heat transport within the <span class="hlt">ocean</span> is prescribed. When modifying the prescribed heat transport we also affect the initial drift of the <span class="hlt">model</span>. We analyze here one of the experiments where this drift is very strong, in order to study the key processes relating the changes in the <span class="hlt">ocean</span> transport and the evolution of the <span class="hlt">model</span>'s <span class="hlt">climate</span>. In this simulation, the <span class="hlt">ocean</span> surface temperature cools by 1.5°C in 20 y. We can distinguish two different phases. During the first period of 5 y, the sea surface temperatures become cooler, particularly in the intertropical area, but the outgoing longwave radiation at the top-of-the-atmosphere increases very quickly, in particular at the end of the period. An off-line version of the <span class="hlt">model</span> radiative code enables us to decompose this behaviour into different contributions (cloudiness, specific humidity, air and surface temperatures, surface albedo). This partitioning shows that the longwave radiation evolution is due to a decrease of high level cirrus clouds in the intertropical troposphere. The decrease of the cloud cover also leads to a decrease of the planetary albedo and therefore an increase of the net short wave radiation absorbed by the system. But the dominant factor is the strong destabilization by the longwave cooling, which is able to throw the system out of equilibrium. During the remaining of the simulation (second phase), the cooling induced by the destabilization at the top-of-the-atmosphere is transmitted to the surface by various processes of the <span class="hlt">climate</span> system. Hence, we show that small variations of <span class="hlt">ocean</span> heat transport can force the <span class="hlt">model</span> from a stable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMED13B0942H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMED13B0942H"><span>Assessing and Upgrading <span class="hlt">Ocean</span> Mixing for the Study of <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howard, A. M.; Fells, J.; Lindo, F.; Tulsee, V.; Canuto, V.; Cheng, Y.; Dubovikov, M. S.; Leboissetier, A.</p> <p>2016-12-01</p> <p><span class="hlt">Climate</span> is critical. <span class="hlt">Climate</span> variability affects us all; <span class="hlt">Climate</span> Change is a burning issue. Droughts, floods, other extreme events, and Global Warming's effects on these and problems such as sea-level rise and ecosystem disruption threaten lives. Citizens must be informed to make decisions concerning <span class="hlt">climate</span> such as "business as usual" vs. mitigating emissions to keep warming within bounds. Medgar Evers undergraduates aid NASA research while learning <span class="hlt">climate</span> science and developing computer&math skills. To make useful predictions we must realistically <span class="hlt">model</span> each component of the <span class="hlt">climate</span> system, including the <span class="hlt">ocean</span>, whose critical role includes transporting&storing heat and dissolved CO2. We need physically based parameterizations of key <span class="hlt">ocean</span> processes that can't be put explicitly in a global <span class="hlt">climate</span> <span class="hlt">model</span>, e.g. vertical&lateral mixing. The NASA-GISS turbulence group uses theory to <span class="hlt">model</span> mixing including: 1) a comprehensive scheme for small scale vertical mixing, including convection&shear, internal waves & double-diffusion, and bottom tides 2) a new parameterization for the lateral&vertical mixing by mesoscale eddies. For better understanding we write our own programs. To assess the <span class="hlt">modelling</span> MATLAB programs visualize and calculate statistics, including means, standard deviations and correlations, on NASA-GISS OGCM output with different mixing schemes and help us study drift from observations. We also try to upgrade the schemes, e.g. the bottom tidal mixing parameterizations' roughness, calculated from high resolution topographic data using Gaussian weighting functions with cut-offs. We study the effects of their parameters to improve them. A FORTRAN program extracts topography data subsets of manageable size for a MATLAB program, tested on idealized cases, to visualize&calculate roughness on. Students are introduced to <span class="hlt">modeling</span> a complex system, gain a deeper appreciation of <span class="hlt">climate</span> science, programming skills and familiarity with MATLAB, while furthering <span class="hlt">climate</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.8927N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.8927N"><span>A regional <span class="hlt">ocean</span> <span class="hlt">model</span> for the Southwest Pacific <span class="hlt">Ocean</span> region to assess the risk of storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Natoo, N.; Paul, A.; Hadfield, M.; Jendersie, S.; Bornman, J.; de Lange, W.; Ye, W.; Schulz, M.</p> <p>2012-04-01</p> <p>New Zealand's coasts are not only affected by mid-latitude storms, but infrequently also by storms that originate from the tropics. Projections for the southern hemisphere's southwest Pacific island countries for the 21st century show a poleward shift of the mid-latitude storm tracks, which consequently might result in changes in wind, precipitation and temperature patterns. Furthermore, an increase in frequency of intense storms is expected for the New Zealand region, which will very likely increase the risk of storm surges and flooding of coastal and low-lying regions. We employ the Regional <span class="hlt">Ocean</span> <span class="hlt">Modeling</span> System (ROMS) to assess the changes in the storm <span class="hlt">climate</span> of the New Zealand region. The <span class="hlt">model</span> set-up uses a resolution of ~50 km for the Southwest Pacific <span class="hlt">Ocean</span> "parent domain" and ~10 km for the New Zealand "child domain", to well represent the major eddies that influence the <span class="hlt">climate</span> of North Island. With the aim to later utilize this nested <span class="hlt">ocean</span> <span class="hlt">model</span> set-up as part of a coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">modelling</span> system for the Southwest Pacific <span class="hlt">Ocean</span> region, results for the 20th century will be presented. The simulated circulation is shown to be largely consistent with the observed regional oceanography.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S44A..01A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S44A..01A"><span>numerical broadband <span class="hlt">modelling</span> of <span class="hlt">ocean</span> waves, from 1 to 300 s: implications for seismic wave sources and wave <span class="hlt">climate</span> studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ardhuin, F.; Stutzmann, E.; Gualtieri, L.</p> <p>2014-12-01</p> <p><span class="hlt">Ocean</span> waves provide most of the energy that feeds the continuous vertical oscillations of the solid Earth. Three period bands are usually identified. The hum contains periods longer than 30 s, and the primary and secondary peaks are usually centered around 15 and 5 s, respectively. Motions in all three bands are recorded everywhere on our planet and can provide information on both the solid Earth structure and the <span class="hlt">ocean</span> wave <span class="hlt">climate</span> over the past century. Here we describe recent efforts to extend the range of validity of <span class="hlt">ocean</span> wave <span class="hlt">models</span> to cover periods from 1 to 300 s (Ardhuin et al., <span class="hlt">Ocean</span> <span class="hlt">Modelling</span> 2014), and the resulting public database of <span class="hlt">ocean</span> wave spectra (http://tinyurl.com/iowagaftp/HINDCAST/ ). We particularly discuss the sources of uncertainty for building a numerical <span class="hlt">model</span> of acoustic and seismic noise on this knowledge of <span class="hlt">ocean</span> wave spectra. For acoustic periods shorter than 3 seconds, the main uncertainties are the directional distributions of wave energy (Ardhuin et al., J. Acoust. Soc. Amer. 2013). For intermediate periods (3 to 25 s), the propagation properties of seismic waves are probably the main source of error when producing synthetic spectra of Rayleigh waves (Ardhuin et al. JGR 2011, Stutzmann et al. GJI 2012). For the longer periods (25 to 300 s), the poor knowledge of the bottom topography details may be the limiting factor for estimating hum spectra or inverting hum measurements in properties of the infragravity wave field. All in all, the space and time variability of recorded seismic and acoustic spectra is generally well reproduced in the band 3 to 300 s, and work on shorter periods is under way. This direct <span class="hlt">model</span> can be used to search for missing noise sources, such as wave scattering in the marginal ice zone, find events relevant for solid earth studies (e.g. Obrebski et al. JGR 2013) or invert wave <span class="hlt">climate</span> properties from microseismic records. The figure shows measured spectra of the vertical ground acceleration, and <span class="hlt">modeled</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150019767&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150019767&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Strengthening of <span class="hlt">Ocean</span> Heat Uptake Efficiency Associated with the Recent <span class="hlt">Climate</span> Hiatus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Watanabe, Masahiro; Kamae, Youichi; Yoshimori, Masakazu; Oka, Akira; Sato, Makiko; Ishii, Masayoshi; Mochizuki, Takashi; Kimoto, Masahide</p> <p>2013-01-01</p> <p>The rate of increase of global-mean surface air temperature (SAT(sub g)) has apparently slowed during the last decade. We investigated the extent to which state-of-the-art general circulation <span class="hlt">models</span> (GCMs) can capture this hiatus period by using multimodel ensembles of historical <span class="hlt">climate</span> simulations. While the SAT(sub g) linear trend for the last decade is not captured by their ensemble means regardless of differences in <span class="hlt">model</span> generation and external forcing, it is barely represented by an 11-member ensemble of a GCM, suggesting an internal origin of the hiatus associated with active heat uptake by the <span class="hlt">oceans</span>. Besides, we found opposite changes in <span class="hlt">ocean</span> heat uptake efficiency (k), weakening in <span class="hlt">models</span> and strengthening in nature, which explain why the <span class="hlt">models</span> tend to overestimate the SAT(sub g) trend. The weakening of k commonly found in GCMs seems to be an inevitable response of the <span class="hlt">climate</span> system to global warming, suggesting the recovery from hiatus in coming decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48.1595K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48.1595K"><span>Fast and slow responses of Southern <span class="hlt">Ocean</span> sea surface temperature to SAM in coupled <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kostov, Yavor; Marshall, John; Hausmann, Ute; Armour, Kyle C.; Ferreira, David; Holland, Marika M.</p> <p>2017-03-01</p> <p>We investigate how sea surface temperatures (SSTs) around Antarctica respond to the Southern Annular Mode (SAM) on multiple timescales. To that end we examine the relationship between SAM and SST within unperturbed preindustrial control simulations of coupled general circulation <span class="hlt">models</span> (GCMs) included in the <span class="hlt">Climate</span> <span class="hlt">Modeling</span> Intercomparison Project phase 5 (CMIP5). We develop a technique to extract the response of the Southern <span class="hlt">Ocean</span> SST (55°S-70°S) to a hypothetical step increase in the SAM index. We demonstrate that in many GCMs, the expected SST step response function is nonmonotonic in time. Following a shift to a positive SAM anomaly, an initial cooling regime can transition into surface warming around Antarctica. However, there are large differences across the CMIP5 ensemble. In some <span class="hlt">models</span> the step response function never changes sign and cooling persists, while in other GCMs the SST anomaly crosses over from negative to positive values only 3 years after a step increase in the SAM. This intermodel diversity can be related to differences in the <span class="hlt">models</span>' climatological thermal <span class="hlt">ocean</span> stratification in the region of seasonal sea ice around Antarctica. Exploiting this relationship, we use observational data for the time-mean meridional and vertical temperature gradients to constrain the real Southern <span class="hlt">Ocean</span> response to SAM on fast and slow timescales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN13B1080C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN13B1080C"><span><span class="hlt">Ocean</span>NOMADS: A New Distribution Node for Operational <span class="hlt">Ocean</span> <span class="hlt">Model</span> Output</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cross, S.; Vance, T.; Breckenridge, T.</p> <p>2009-12-01</p> <p>The NOAA National Operational <span class="hlt">Model</span> Archive and Distribution System (NOMADS) is a distributed, web-services based project providing real-time and retrospective access to <span class="hlt">climate</span> and weather <span class="hlt">model</span> data and related datasets. <span class="hlt">Ocean</span>NOMADS is a new NOMADS node dedicated to <span class="hlt">ocean</span> <span class="hlt">model</span> and related data, with an initial focus on operational <span class="hlt">ocean</span> <span class="hlt">models</span> from NOAA and the U.S. Navy. The node offers data access through a Thematic Real-time Environmental Distributed Data Services (THREDDS) server via the commonly used OPeNDAP protocol. The primary server is operated by the National Coastal Data Development Center and hosted by the Northern Gulf Institute at Stennis Space Center, MS. In cooperation with the National Marine Fisheries Service and Mississippi State University (MSU), a duplicate server is being installed at MSU with a 1-gigabit connection to the National Lambda Rail. This setup will allow us to begin to quantify the benefit of high-speed data connections to scientists needing remote access to these large datasets. Work is also underway on the next generation of services from <span class="hlt">Ocean</span>NOMADS, including user-requested server-side data reformatting, regridding, and aggregation, as well as tools for <span class="hlt">model</span>-data comparison.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1378474','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1378474"><span>AMOC decadal variability in Earth system <span class="hlt">models</span>: Mechanisms and <span class="hlt">climate</span> impacts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fedorov, Alexey</p> <p></p> <p>This is the final report for the project titled "AMOC decadal variability in Earth system <span class="hlt">models</span>: Mechanisms and <span class="hlt">climate</span> impacts". The central goal of this one-year research project was to understand the mechanisms of decadal and multi-decadal variability of the Atlantic Meridional Overturning Circulation (AMOC) within a hierarchy of <span class="hlt">climate</span> <span class="hlt">models</span> ranging from realistic <span class="hlt">ocean</span> GCMs to Earth system <span class="hlt">models</span>. The AMOC is a key element of <span class="hlt">ocean</span> circulation responsible for <span class="hlt">oceanic</span> transport of heat from low to high latitudes and controlling, to a large extent, <span class="hlt">climate</span> variations in the North Atlantic. The questions of the AMOC stability, variability andmore » predictability, directly relevant to the questions of <span class="hlt">climate</span> predictability, were at the center of the research work.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPC12A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPC12A..07L"><span>Past <span class="hlt">climates</span> primary productivity changes in the Indian <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Le Mézo, P. K.; Kageyama, M.; Bopp, L.; Beaufort, L.; Braconnot, P.; Bassinot, F. C.</p> <p>2016-02-01</p> <p>Organic <span class="hlt">climate</span> recorders, e.g., coccolithophorids and foraminifera, are widely used to reconstruct past <span class="hlt">climate</span> conditions, such as the Indian monsoon intensity and variability, since they are sensitive to <span class="hlt">climate</span>-induced fluctuations of their environment. In the Indian <span class="hlt">Ocean</span>, it is commonly accepted that a stronger summer monsoon will enhance productivity in the Arabian Sea and therefore the amount of organisms in a sediment core should reflect monsoon intensity. In this study, we use the coupled Earth System <span class="hlt">Model</span> IPSLCM5A, which has a biogeochemical component PISCES that simulates primary production. We use 8 <span class="hlt">climate</span> simulations of the IPSL-CM5A <span class="hlt">model</span>, from -72kyr BP <span class="hlt">climate</span> conditions to a preindustrial state. Our simulations have different orbital forcing (precession, obliquity and eccentricity), greenhouse gas concentrations as well as different ice sheet covers. The objective of this work is to characterize the mechanisms behind the changes in primary productivity between the different time periods. Our <span class="hlt">model</span> shows that in <span class="hlt">climates</span> where monsoon is enhanced (due to changes in precession) we do not necessarily see an increase in summer productivity in the Arabian Sea, and inversely. It seems that the glacial-interglacial state of the simulation is important in driving productivity changes in this region of the world. We try to explain the changes in productivity in the Arabian Sea with the local <span class="hlt">climate</span> and then to link the changes in local <span class="hlt">climate</span> to large scale atmospheric forcing and commonly used Indian monsoon definitions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNG13A1700N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNG13A1700N"><span>Improved Analysis of Earth System <span class="hlt">Models</span> and Observations using Simple <span class="hlt">Climate</span> <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nadiga, B. T.; Urban, N. M.</p> <p>2016-12-01</p> <p>Earth system <span class="hlt">models</span> (ESM) are the most comprehensive tools we have to study <span class="hlt">climate</span> change and develop <span class="hlt">climate</span> projections. However, the computational infrastructure required and the cost incurred in running such ESMs precludes direct use of such <span class="hlt">models</span> in conjunction with a wide variety of tools that can further our understanding of <span class="hlt">climate</span>. Here we are referring to tools that range from dynamical systems tools that give insight into underlying flow structure and topology to tools that come from various applied mathematical and statistical techniques and are central to quantifying stability, sensitivity, uncertainty and predictability to machine learning tools that are now being rapidly developed or improved. Our approach to facilitate the use of such <span class="hlt">models</span> is to analyze output of ESM experiments (cf. CMIP) using a range of simpler <span class="hlt">models</span> that consider integral balances of important quantities such as mass and/or energy in a Bayesian framework.We highlight the use of this approach in the context of the uptake of heat by the world <span class="hlt">oceans</span> in the ongoing global warming. Indeed, since in excess of 90% of the anomalous radiative forcing due greenhouse gas emissions is sequestered in the world <span class="hlt">oceans</span>, the nature of <span class="hlt">ocean</span> heat uptake crucially determines the surface warming that is realized (cf. <span class="hlt">climate</span> sensitivity). Nevertheless, ESMs themselves are never run long enough to directly assess <span class="hlt">climate</span> sensitivity. So, we consider a range of <span class="hlt">models</span> based on integral balances--balances that have to be realized in all first-principles based <span class="hlt">models</span> of the <span class="hlt">climate</span> system including the most detailed state-of-the art <span class="hlt">climate</span> simulations. The <span class="hlt">models</span> range from simple <span class="hlt">models</span> of energy balance to those that consider dynamically important <span class="hlt">ocean</span> processes such as the conveyor-belt circulation (Meridional Overturning Circulation, MOC), North Atlantic Deep Water (NADW) formation, Antarctic Circumpolar Current (ACC) and eddy mixing. Results from Bayesian analysis of such <span class="hlt">models</span> using</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.4263B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.4263B"><span>Drivers of Arctic <span class="hlt">Ocean</span> warming in CMIP5 <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burgard, Clara; Notz, Dirk</p> <p>2017-05-01</p> <p>We investigate changes in the Arctic <span class="hlt">Ocean</span> energy budget simulated by 26 general circulation <span class="hlt">models</span> from the Coupled <span class="hlt">Model</span> Intercomparison Project Phase 5 framework. Our goal is to understand whether the Arctic <span class="hlt">Ocean</span> warming between 1961 and 2099 is primarily driven by changes in the net atmospheric surface flux or by changes in the meridional <span class="hlt">oceanic</span> heat flux. We find that the simulated Arctic <span class="hlt">Ocean</span> warming is driven by positive anomalies in the net atmospheric surface flux in 11 <span class="hlt">models</span>, by positive anomalies in the meridional <span class="hlt">oceanic</span> heat flux in 11 <span class="hlt">models</span>, and by positive anomalies in both energy fluxes in four <span class="hlt">models</span>. The different behaviors are mainly characterized by the different changes in meridional <span class="hlt">oceanic</span> heat flux that lead to different changes in the turbulent heat loss to the atmosphere. The multimodel ensemble mean is hence not representative of a consensus across the <span class="hlt">models</span> in Arctic <span class="hlt">climate</span> projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A32E..04Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A32E..04Y"><span>Observed <span class="hlt">Oceanic</span> and Terrestrial Drivers of North African <span class="hlt">Climate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Y.; Notaro, M.; Wang, F.; Mao, J.; Shi, X.; Wei, Y.</p> <p>2015-12-01</p> <p>Hydrologic variability can pose a serious threat to the poverty-stricken regions of North Africa. Yet, the current understanding of <span class="hlt">oceanic</span> versus terrestrial drivers of North African droughts/pluvials is largely <span class="hlt">model</span>-based, with vast disagreement among <span class="hlt">models</span>. In order to identify the observed drivers of North African <span class="hlt">climate</span> and develop a benchmark for <span class="hlt">model</span> evaluations, the multivariate Generalized Equilibrium Feedback Assessment (GEFA) is applied to observations, remotely sensed data, and reanalysis products. The identified primary <span class="hlt">oceanic</span> drivers of North African rainfall variability are the Atlantic, tropical Indian, and tropical Pacific <span class="hlt">Oceans</span> and Mediterranean Sea. During the summer monsoon, positive tropical eastern Atlantic sea-surface temperature (SST) anomalies are associated with a southward shift of the Inter-Tropical Convergence Zone, enhanced <span class="hlt">ocean</span> evaporation, and greater precipitable water across coastal West Africa, leading to increased West African monsoon (WAM) rainfall and decreased Sahel rainfall. During the short rains, positive SST anomalies in the western tropical Indian <span class="hlt">Ocean</span> and negative anomalies in the eastern tropical Indian <span class="hlt">Ocean</span> support greater easterly <span class="hlt">oceanic</span> flow, evaporation over the western <span class="hlt">ocean</span>, and moisture advection to East Africa, thereby enhancing rainfall. The sign, magnitude, and timing of observed vegetation forcing on rainfall vary across North Africa. The positive feedback of leaf area index (LAI) on rainfall is greatest during DJF for the Horn of Africa, while it peaks in autumn and is weakest during the summer monsoon for the Sahel. Across the WAM region, a positive LAI anomaly supports an earlier monsoon onset, increased rainfall during the pre-monsoon, and decreased rainfall during the wet season. Through unique mechanisms, positive LAI anomalies favor enhanced transpiration, precipitable water, and rainfall across the Sahel and Horn of Africa, and increased roughness, ascent, and rainfall across the WAM region</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C51A0254Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C51A0254Y"><span><span class="hlt">Modelling</span> the <span class="hlt">Climate</span> - Greenland Ice Sheet Interaction in the Coupled Ice-sheet/<span class="hlt">Climate</span> <span class="hlt">Model</span> EC-EARTH - PISM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, S.; Madsen, M. S.; Rodehacke, C. B.; Svendsen, S. H.; Adalgeirsdottir, G.</p> <p>2014-12-01</p> <p>Recent observations show that the Greenland ice sheet (GrIS) has been losing mass with an increasing speed during the past decades. Predicting the GrIS changes and their <span class="hlt">climate</span> consequences relies on the understanding of the interaction of the GrIS with the <span class="hlt">climate</span> system on both global and local scales, and requires <span class="hlt">climate</span> <span class="hlt">model</span> systems with an explicit and physically consistent ice sheet module. A fully coupled global <span class="hlt">climate</span> <span class="hlt">model</span> with a dynamical ice sheet <span class="hlt">model</span> for the GrIS has recently been developed. The <span class="hlt">model</span> system, EC-EARTH - PISM, consists of the EC-EARTH, an atmosphere, <span class="hlt">ocean</span> and sea ice <span class="hlt">model</span> system, and the Parallel Ice Sheet <span class="hlt">Model</span> (PISM). The coupling of PISM includes a modified surface physical parameterization in EC-EARTH adapted to the land ice surface over glaciated regions in Greenland. The PISM ice sheet <span class="hlt">model</span> is forced with the surface mass balance (SMB) directly computed inside the EC-EARTH atmospheric module and accounting for the precipitation, the surface evaporation, and the melting of snow and ice over land ice. PISM returns the simulated basal melt, ice discharge and ice cover (extent and thickness) as boundary conditions to EC-EARTH. This coupled system is mass and energy conserving without being constrained by any anomaly correction or flux adjustment, and hence is suitable for investigation of ice sheet - <span class="hlt">climate</span> feedbacks. Three multi-century experiments for warm <span class="hlt">climate</span> scenarios under (1) the RCP85 <span class="hlt">climate</span> forcing, (2) an abrupt 4xCO2 and (3) an idealized 1% per year CO2 increase are performed using the coupled <span class="hlt">model</span> system. The experiments are compared with their counterparts of the standard CMIP5 simulations (without the interactive ice sheet) to evaluate the performance of the coupled system and to quantify the GrIS feedbacks. In particular, the evolution of the Greenland ice sheet under the warm <span class="hlt">climate</span> and its impacts on the <span class="hlt">climate</span> system are investigated. Freshwater fluxes from the Greenland ice sheet melt to the Arctic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840012144','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840012144"><span><span class="hlt">Ocean</span> <span class="hlt">modelling</span> on the CYBER 205 at GFDL</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cox, M.</p> <p>1984-01-01</p> <p>At the Geophysical Fluid Dynamics Laboratory, research is carried out for the purpose of understanding various aspects of <span class="hlt">climate</span>, such as its variability, predictability, stability and sensitivity. The atmosphere and <span class="hlt">oceans</span> are <span class="hlt">modelled</span> mathematically and their phenomenology studied by computer simulation methods. The present state-of-the-art in the computer simulation of large scale <span class="hlt">oceans</span> on the CYBER 205 is discussed. While atmospheric <span class="hlt">modelling</span> differs in some aspects, the basic approach used is similar. The equations of the <span class="hlt">ocean</span> <span class="hlt">model</span> are presented along with a short description of the numerical techniques used to find their solution. Computational considerations and a typical solution are presented in section 4.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhDT.......266B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhDT.......266B"><span>On the physical air-sea fluxes for <span class="hlt">climate</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonekamp, J. G.</p> <p>2001-02-01</p> <p>At the sea surface, the atmosphere and the <span class="hlt">ocean</span> exchange momentum, heat and freshwater. Mechanisms for the exchange are wind stress, turbulent mixing, radiation, evaporation and precipitation. These surface fluxes are characterized by a large spatial and temporal variability and play an important role in not only the mean atmospheric and <span class="hlt">oceanic</span> circulation, but also in the generation and sustainment of coupled <span class="hlt">climate</span> fluctuations such as the El Niño/La Niña phenomenon. Therefore, a good knowledge of air-sea fluxes is required for the understanding and prediction of <span class="hlt">climate</span> changes. As part of long-term comprehensive atmospheric reanalyses with `Numerical Weather Prediction/Data assimilation' systems, data sets of global air-sea fluxes are generated. A good example is the 15-year atmospheric reanalysis of the European Centre for Medium--Range Weather Forecasts (ECMWF). Air-sea flux data sets from these reanalyses are very beneficial for <span class="hlt">climate</span> research, because they combine a good spatial and temporal coverage with a homogeneous and consistent method of calculation. However, atmospheric reanalyses are still imperfect sources of flux information due to shortcomings in <span class="hlt">model</span> variables, <span class="hlt">model</span> parameterizations, assimilation methods, sampling of observations, and quality of observations. Therefore, assessments of the errors and the usefulness of air-sea flux data sets from atmospheric (re-)analyses are relevant contributions to the quantitative study of <span class="hlt">climate</span> variability. Currently, much research is aimed at assessing the quality and usefulness of the reanalysed air-sea fluxes. Work in this thesis intends to contribute to this assessment. In particular, it attempts to answer three relevant questions. The first question is: What is the best parameterization of the momentum flux? A comparison is made of the wind stress parameterization of the ERA15 reanalysis, the currently generated ERA40 reanalysis and the wind stress measurements over the open <span class="hlt">ocean</span>. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26742651','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26742651"><span>Observing <span class="hlt">climate</span> change trends in <span class="hlt">ocean</span> biogeochemistry: when and where.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Henson, Stephanie A; Beaulieu, Claudie; Lampitt, Richard</p> <p>2016-04-01</p> <p>Understanding the influence of anthropogenic forcing on the marine biosphere is a high priority. <span class="hlt">Climate</span> change-driven trends need to be accurately assessed and detected in a timely manner. As part of the effort towards detection of long-term trends, a network of <span class="hlt">ocean</span> observatories and time series stations provide high quality data for a number of key parameters, such as pH, oxygen concentration or primary production (PP). Here, we use an ensemble of global coupled <span class="hlt">climate</span> <span class="hlt">models</span> to assess the temporal and spatial scales over which observations of eight biogeochemically relevant variables must be made to robustly detect a long-term trend. We find that, as a global average, continuous time series are required for between 14 (pH) and 32 (PP) years to distinguish a <span class="hlt">climate</span> change trend from natural variability. Regional differences are extensive, with low latitudes and the Arctic generally needing shorter time series (<~30 years) to detect trends than other areas. In addition, we quantify the 'footprint' of existing and planned time series stations, that is the area over which a station is representative of a broader region. Footprints are generally largest for pH and sea surface temperature, but nevertheless the existing network of observatories only represents 9-15% of the global <span class="hlt">ocean</span> surface. Our results present a quantitative framework for assessing the adequacy of current and future <span class="hlt">ocean</span> observing networks for detection and monitoring of <span class="hlt">climate</span> change-driven responses in the marine ecosystem. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPC54C2265P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPC54C2265P"><span>Alexander Polonsky Global warming hiatus, <span class="hlt">ocean</span> variability and regional <span class="hlt">climate</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polonsky, A.</p> <p>2016-02-01</p> <p>This presentation generalizes the results concerning <span class="hlt">ocean</span> variability, large-scale interdecadal <span class="hlt">ocean</span>-atmosphere interaction in the Atlantic and Pacific <span class="hlt">Oceans</span> and their impact on global and regional <span class="hlt">climate</span> change carried out by the author and his colleagues for about 20 years. It is demonstrated once more that Atlantic Multidecadal Oscillation (AMO, which was early referred by the author as "interdecadal mode of North Atlantic Oscillation") is the crucial natural interdecadal <span class="hlt">climatic</span> signal for the Atlantic-European and Mediterranean regions. It is characterized by amplitude which is the same order as human-induced centennial <span class="hlt">climate</span> change and exceeds trend-like anthropogenic change at the decadal scale. Fast increasing of the global and Northern Hemisphere air temperature in the last 30 yrs of XX century (especially pronounced in the North Atlantic region and surrounded areas) is due to coincidence of human-induced positive trend and transition from the negative to the positive phase of AMO. AMO accounts for about 50% (60%) of the global (Northern Hemisphere) temperature trend in that period. Recent global warming hiatus is mostly the result of switch off the AMO phase. Typical AMO temporal scale is dictated by meridional overturning variability in the Atlantic <span class="hlt">Ocean</span> and associated magnitude of meridional heat transport. Pacific Decadal Oscillation (PDO) is the other natural interdecadal signal which significantly impacts the global and regional <span class="hlt">climate</span> variability. The rate of the <span class="hlt">ocean</span> warming for different periods assessed separately for the upper mixed layer and deeper layers using data of <span class="hlt">oceanic</span> re-analysis since 1959 confirms the principal role of the natural interdecadal <span class="hlt">oceanic</span> modes (AMO and PDO) in observing <span class="hlt">climate</span> change. At the same time a lack of deep-<span class="hlt">ocean</span> long-term observing system restricts the accuracy of assessment of the heat redistribution in the World <span class="hlt">Ocean</span>. I thanks to Pavel Sukhonos for help in the presentation preparing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OcDyn..67..621G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OcDyn..67..621G"><span>Impacts of <span class="hlt">climate</span> changes on <span class="hlt">ocean</span> surface gravity waves over the eastern Canadian shelf</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Lanli; Sheng, Jinyu</p> <p>2017-05-01</p> <p>A numerical study is conducted to investigate the impact of <span class="hlt">climate</span> changes on <span class="hlt">ocean</span> surface gravity waves over the eastern Canadian shelf (ECS). The "business-as-usual" <span class="hlt">climate</span> scenario known as Representative Concentration Pathway RCP8.5 is considered in this study. Changes in the <span class="hlt">ocean</span> surface gravity waves over the study region for the period 1979-2100 are examined based on 3 hourly <span class="hlt">ocean</span> waves simulated by the third-generation <span class="hlt">ocean</span> wave <span class="hlt">model</span> known as WAVEWATCHIII. The wave <span class="hlt">model</span> is driven by surface winds and ice conditions produced by the Canadian Regional <span class="hlt">Climate</span> <span class="hlt">Model</span> (CanRCM4). The whole study period is divided into the present (1979-2008), near future (2021-2050) and far future (2071-2100) periods to quantify possible future changes of <span class="hlt">ocean</span> waves over the ECS. In comparison with the present <span class="hlt">ocean</span> wave conditions, the time-mean significant wave heights ( H s ) are expected to increase over most of the ECS in the near future and decrease over this region in the far future period. The time-means of the annual 5% largest H s are projected to increase over the ECS in both near and far future periods due mainly to the changes in surface winds. The future changes in the time-means of the annual 5% largest H s and 10-m wind speeds are projected to be twice as strong as the changes in annual means. An analysis of inverse wave ages suggests that the occurrence of wind seas is projected to increase over the southern Labrador and central Newfoundland Shelves in the near future period, and occurrence of swells is projected to increase over other areas of the ECS in both the near and far future periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150023406&hterms=Summer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSummer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150023406&hterms=Summer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSummer"><span>Downscaling GISS <span class="hlt">ModelE</span> Boreal Summer <span class="hlt">Climate</span> over Africa</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Druyan, Leonard M.; Fulakeza, Matthew</p> <p>2015-01-01</p> <p>The study examines the perceived added value of downscaling atmosphere-<span class="hlt">ocean</span> global <span class="hlt">climate</span> <span class="hlt">model</span> simulations over Africa and adjacent <span class="hlt">oceans</span> by a nested regional <span class="hlt">climate</span> <span class="hlt">model</span>. NASA/Goddard Institute for Space Studies (GISS) coupled <span class="hlt">ModelE</span> simulations for June- September 1998-2002 are used to form lateral boundary conditions for synchronous simulations by the GISS RM3 regional <span class="hlt">climate</span> <span class="hlt">model</span>. The <span class="hlt">ModelE</span> computational grid spacing is 2deg latitude by 2.5deg longitude and the RM3 grid spacing is 0.44deg. <span class="hlt">ModelE</span> precipitation climatology for June-September 1998-2002 is shown to be a good proxy for 30-year means so results based on the 5-year sample are presumed to be generally representative. Comparison with observational evidence shows several discrepancies in <span class="hlt">ModelE</span> configuration of the boreal summer inter-tropical convergence zone (ITCZ). One glaring shortcoming is that <span class="hlt">ModelE</span> simulations do not advance the West African rain band northward during the summer to represent monsoon precipitation onset over the Sahel. Results for 1998-2002 show that onset simulation is an important added value produced by downscaling with RM3. <span class="hlt">ModelE</span> Eastern South Atlantic <span class="hlt">Ocean</span> computed sea-surface temperatures (SST) are some 4 K warmer than reanalysis, contributing to large positive biases in overlying surface air temperatures (Tsfc). <span class="hlt">ModelE</span> Tsfc are also too warm over most of Africa. RM3 downscaling somewhat mitigates the magnitude of Tsfc biases over the African continent, it eliminates the <span class="hlt">ModelE</span> double ITCZ over the Atlantic and it produces more realistic orographic precipitation maxima. Parallel <span class="hlt">ModelE</span> and RM3 simulations with observed SST forcing (in place of the predicted <span class="hlt">ocean</span>) lower Tsfc errors but have mixed impacts on circulation and precipitation biases. Downscaling improvements of the meridional movement of the rain band over West Africa and the configuration of orographic precipitation maxima are realized irrespective of the SST biases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5562405','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5562405"><span>Evaluating and Extending the <span class="hlt">Ocean</span> Wind <span class="hlt">Climate</span> Data Record</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ricciardulli, Lucrezia; Rodriguez, Ernesto; Stiles, Bryan W.; Bourassa, Mark A.; Long, David G.; Hoffman, Ross N.; Stoffelen, Ad; Verhoef, Anton; O'Neill, Larry W.; Farrar, J. Tomas; Vandemark, Douglas; Fore, Alexander G.; Hristova-Veleva, Svetla M.; Turk, F. Joseph; Gaston, Robert; Tyler, Douglas</p> <p>2017-01-01</p> <p>Satellite microwave sensors, both active scatterometers and passive radiometers, have been systematically measuring near-surface <span class="hlt">ocean</span> winds for nearly 40 years, establishing an important legacy in studying and monitoring weather and <span class="hlt">climate</span> variability. As an aid to such activities, the various wind datasets are being intercalibrated and merged into consistent <span class="hlt">climate</span> data records (CDRs). The <span class="hlt">ocean</span> wind CDRs (OW-CDRs) are evaluated by comparisons with <span class="hlt">ocean</span> buoys and intercomparisons among the different satellite sensors and among the different data providers. Extending the OW-CDR into the future requires exploiting all available datasets, such as OSCAT-2 scheduled to launch in July 2016. Three planned methods of calibrating the OSCAT-2 σo measurements include 1) direct Ku-band σo intercalibration to QuikSCAT and RapidScat; 2) multisensor wind speed intercalibration; and 3) calibration to stable rainforest targets. Unfortunately, RapidScat failed in August 2016 and cannot be used to directly calibrate OSCAT-2. A particular future continuity concern is the absence of scheduled new or continuation radiometer missions capable of measuring wind speed. Specialized <span class="hlt">model</span> assimilations provide 30-year long high temporal/spatial resolution wind vector grids that composite the satellite wind information from OW-CDRs of multiple satellites viewing the Earth at different local times. PMID:28824741</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28824741','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28824741"><span>Evaluating and Extending the <span class="hlt">Ocean</span> Wind <span class="hlt">Climate</span> Data Record.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wentz, Frank J; Ricciardulli, Lucrezia; Rodriguez, Ernesto; Stiles, Bryan W; Bourassa, Mark A; Long, David G; Hoffman, Ross N; Stoffelen, Ad; Verhoef, Anton; O'Neill, Larry W; Farrar, J Tomas; Vandemark, Douglas; Fore, Alexander G; Hristova-Veleva, Svetla M; Turk, F Joseph; Gaston, Robert; Tyler, Douglas</p> <p>2017-05-01</p> <p>Satellite microwave sensors, both active scatterometers and passive radiometers, have been systematically measuring near-surface <span class="hlt">ocean</span> winds for nearly 40 years, establishing an important legacy in studying and monitoring weather and <span class="hlt">climate</span> variability. As an aid to such activities, the various wind datasets are being intercalibrated and merged into consistent <span class="hlt">climate</span> data records (CDRs). The <span class="hlt">ocean</span> wind CDRs (OW-CDRs) are evaluated by comparisons with <span class="hlt">ocean</span> buoys and intercomparisons among the different satellite sensors and among the different data providers. Extending the OW-CDR into the future requires exploiting all available datasets, such as OSCAT-2 scheduled to launch in July 2016. Three planned methods of calibrating the OSCAT-2 σ o measurements include 1) direct Ku-band σ o intercalibration to QuikSCAT and RapidScat; 2) multisensor wind speed intercalibration; and 3) calibration to stable rainforest targets. Unfortunately, RapidScat failed in August 2016 and cannot be used to directly calibrate OSCAT-2. A particular future continuity concern is the absence of scheduled new or continuation radiometer missions capable of measuring wind speed. Specialized <span class="hlt">model</span> assimilations provide 30-year long high temporal/spatial resolution wind vector grids that composite the satellite wind information from OW-CDRs of multiple satellites viewing the Earth at different local times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918814F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918814F"><span>Assessment of <span class="hlt">ocean</span> <span class="hlt">models</span> in Mediterranean Sea against altimetry and gravimetry measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fenoglio-Marc, Luciana; Uebbing, Bernd; Kusche, Jürgen</p> <p>2017-04-01</p> <p>This work aims at assessing in a regional study in the Mediterranean Sea the agreement between <span class="hlt">ocean</span> <span class="hlt">model</span> outputs and satellite altimetry and satellite gravity observations. Satellite sea level change are from altimeter data made available by the Sea Level <span class="hlt">Climate</span> Change Initiative (SLCCI) and from satellite gravity data made available by GRACE. We consider two <span class="hlt">ocean</span> simulations not assimilating satellite altimeter data and one <span class="hlt">ocean</span> <span class="hlt">model</span> reanalysis assimilating satellite altimetry. <span class="hlt">Ocean</span> <span class="hlt">model</span> simulations can provide some insight on the <span class="hlt">ocean</span> variability, but they are affected by biases due to errors in <span class="hlt">model</span> formulation, specification of initial states and forcing, and are not directly constrained by observations. Their trend can be quite different from the altimetric observations due to surface radiation biases, however they are physically consistent. <span class="hlt">Ocean</span> reanalyses are the combination of <span class="hlt">ocean</span> <span class="hlt">models</span>, atmospheric forcing fluxes and <span class="hlt">ocean</span> observations via data assimilation methods and have the potential to provide more accurate information than observation-only or <span class="hlt">model</span>-only based <span class="hlt">ocean</span> estimations. They will be closer to altimetry at long and short timescales, but assimilation may destroy mass consistency. We use two <span class="hlt">ocean</span> simulations which are part of the Med-CORDEX initiative (https://www.medcordex.eu). The first is the CNRM-RCM4 fully-coupled Regional <span class="hlt">Climate</span> System <span class="hlt">Model</span> (RCMS) simulation developed at METEOFRANCE for 1980-2012. The second is the PROTHEUS standalone hindcast simulation developed at ENEA and covers the interval 1960-2012. The third <span class="hlt">model</span> is the regional <span class="hlt">model</span> MEDSEA_REANALYSIS_PHIS_006_004 assimilating satellite altimeter data (http://marine.copernicus.eu/) and available over 1987-2014. Comparison at basin and regional scale are made. First the steric, thermo-steric, halosteric and dynamic components output of the <span class="hlt">models</span> are compared. Then the total sea level given by the <span class="hlt">models</span> is compared to the altimeter observations. Finally the mass</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19341144','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19341144"><span>Range-wide reproductive consequences of <span class="hlt">ocean</span> <span class="hlt">climate</span> variability for the seabird Cassin's Auklet.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wolf, Shaye G; Sydeman, William J; Hipfner, J Mark; Abraham, Christine L; Tershy, Bernie R; Croll, Donald A</p> <p>2009-03-01</p> <p>We examine how <span class="hlt">ocean</span> <span class="hlt">climate</span> variability influences the reproductive phenology and demography of the seabird Cassin's Auklet (Ptychoramphus aleuticus) across approximately 2500 km of its breeding range in the oceanographically dynamic California Current System along the west coast of North America. Specifically, we determine the extent to which <span class="hlt">ocean</span> <span class="hlt">climate</span> conditions and Cassin's Auklet timing of breeding and breeding success covary across populations in British Columbia, central California, and northern Mexico over six years (2000-2005) and test whether auklet timing of breeding and breeding success are similarly related to local and large-scale <span class="hlt">ocean</span> <span class="hlt">climate</span> indices across populations. Local <span class="hlt">ocean</span> foraging environments ranged from seasonally variable, high-productivity environments in the north to aseasonal, low-productivity environments to the south, but covaried similarly due to the synchronizing effects of large-scale <span class="hlt">climate</span> processes. Auklet timing of breeding in the southern population did not covary with populations to the north and was not significantly related to local oceanographic conditions, in contrast to northern populations, where timing of breeding appears to be influenced by oceanographic cues that signal peaks in prey availability. Annual breeding success covaried similarly across populations and was consistently related to local <span class="hlt">ocean</span> <span class="hlt">climate</span> conditions across this system. Overall, local <span class="hlt">ocean</span> <span class="hlt">climate</span> indices, particularly sea surface height, better explained timing of breeding and breeding success than a large-scale <span class="hlt">climate</span> index by better representing heterogeneity in physical processes important to auklets and their prey. The significant, consistent relationships we detected between Cassin's Auklet breeding success and <span class="hlt">ocean</span> <span class="hlt">climate</span> conditions across widely spaced populations indicate that Cassin's Auklets are susceptible to <span class="hlt">climate</span> change across the California Current System, especially by the strengthening of <span class="hlt">climate</span> processes that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70044659','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70044659"><span>Bioenergetic response by steelhead to variation in diet, thermal habitat, and <span class="hlt">climate</span> in the north Pacific <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Atcheson, Margaret E.; Myers, Katherine W.; Beauchamp, David A.; Mantua, Nathan J.</p> <p>2012-01-01</p> <p>Energetic responses of steelhead Oncorhynchus mykiss to <span class="hlt">climate</span>-driven changes in marine conditions are expected to affect the species’ <span class="hlt">ocean</span> distribution, feeding, growth, and survival. With a unique 18-year data series (1991–2008) for steelhead sampled in the open <span class="hlt">ocean</span>, we simulated interannual variation in prey consumption and growth efficiency of steelhead using a bioenergetics <span class="hlt">model</span> to evaluate the temperature-dependent growth response of steelhead to past <span class="hlt">climate</span> events and to estimate growth potential of steelhead under future <span class="hlt">climate</span> scenarios. Our results showed that annual <span class="hlt">ocean</span> growth of steelhead is highly variable depending on prey quality, consumption rates, total consumption, and thermal experience. At optimal growing temperatures, steelhead can compensate for a low-energy diet by increasing consumption rates and consuming more prey, if available. Our findings suggest that steelhead have a narrow temperature window in which to achieve optimal growth, which is strongly influenced by <span class="hlt">climate</span>-driven changes in <span class="hlt">ocean</span> temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1225814','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1225814"><span>Characterization of the Dynamics of <span class="hlt">Climate</span> Systems and Identification of Missing Mechanisms Impacting the Long Term Predictive Capabilities of Global <span class="hlt">Climate</span> <span class="hlt">Models</span> Utilizing Dynamical Systems Approaches to the Analysis of Observed and <span class="hlt">Modeled</span> <span class="hlt">Climate</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bhatt, Uma S.; Wackerbauer, Renate; Polyakov, Igor V.</p> <p></p> <p>The goal of this research was to apply fractional and non-linear analysis techniques in order to develop a more complete characterization of <span class="hlt">climate</span> change and variability for the <span class="hlt">oceanic</span>, sea ice and atmospheric components of the Earth System. This research applied two measures of dynamical characteristics of time series, the R/S method of calculating the Hurst exponent and Renyi entropy, to observational and <span class="hlt">modeled</span> <span class="hlt">climate</span> data in order to evaluate how well <span class="hlt">climate</span> <span class="hlt">models</span> capture the long-term dynamics evident in observations. Fractional diffusion analysis was applied to ARGO <span class="hlt">ocean</span> buoy data to quantify <span class="hlt">ocean</span> transport. Self organized maps were appliedmore » to North Pacific sea level pressure and analyzed in ways to improve seasonal predictability for Alaska fire weather. This body of research shows that these methods can be used to evaluate <span class="hlt">climate</span> <span class="hlt">models</span> and shed light on <span class="hlt">climate</span> mechanisms (i.e., understanding why something happens). With further research, these methods show promise for improving seasonal to longer time scale forecasts of <span class="hlt">climate</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011CliPD...7.1973H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011CliPD...7.1973H"><span>Tropical <span class="hlt">climate</span> and vegetation changes during Heinrich Event 1: comparing <span class="hlt">climate</span> <span class="hlt">model</span> output to pollen-based vegetation reconstructions with emphasis on the region around the tropical Atlantic <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Handiani, D.; Paul, A.; Dupont, L.</p> <p>2011-06-01</p> <p>Abrupt <span class="hlt">climate</span> changes associated with Heinrich Event 1 (HE1) about 18 to 15 thousand years before present (ka BP) strongly affected <span class="hlt">climate</span> and vegetation patterns not only in the Northern Hemisphere, but also in tropical regions in the South Atlantic <span class="hlt">Ocean</span>. We used the University of Victoria (UVic) Earth System-<span class="hlt">Climate</span> <span class="hlt">Model</span> (ESCM) with dynamical vegetation and land surface components to simulate four scenarios of <span class="hlt">climate</span>-vegetation interaction: the pre-industrial era (PI), the Last Glacial Maximum (LGM), and a Heinrich-like event with two different <span class="hlt">climate</span> backgrounds (interglacial and glacial). The HE1-like simulation with a glacial <span class="hlt">climate</span> background produced sea surface temperature patterns and enhanced interhemispheric thermal gradients in accordance with the "bipolar seesaw" hypothesis. It allowed us to investigate the vegetation changes that result from a transition to a drier <span class="hlt">climate</span> as predicted for northern tropical Africa due to a southward shift of the Intertropical Convergence Zone (ITCZ). We found that a cooling of the Northern Hemisphere caused a southward shift of those plant-functional types (PFTs) in Northern Tropical Africa that are indicative of an increased desertification, and a retreat of broadleaf forests in Western Africa and Northern South America. We used the PFTs generated by the <span class="hlt">model</span> to calculate mega-biomes to allow for a direct comparison between paleodata and palynological vegetation reconstructions. Our calculated mega-biomes for the pre-industrial period and the LGM corresponded well to the modern and LGM sites of the BIOME6000 (v.4.2) reconstruction, except that our present-day simulation predicted the dominance of grassland in Southern Europe and our LGM simulation simulated more forest cover in tropical and sub-tropical South America. The mega-biomes from the HE1 simulation with glacial background <span class="hlt">climate</span> were in agreement with paleovegetation data from land and <span class="hlt">ocean</span> proxies in West, Central, and Northern Tropical Africa as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911392T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911392T"><span>Mass and tracer transport within <span class="hlt">oceanic</span> Lagrangian coherent vortices as diagnosed in a global mesoscale eddying <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tarshish, Nathaniel; Abernathey, Ryan; Dufour, Carolina; Frenger, Ivy; Griffies, Stephen</p> <p>2017-04-01</p> <p>Transient <span class="hlt">ocean</span> mesoscale fluctuations play a central role in the global <span class="hlt">climate</span> system, transporting <span class="hlt">climate</span> relevant tracers such as heat and carbon. In satellite observations and numerical simulations, mesoscale vortices feature prominently as collectively rotating regions that remain visibly coherent. Prior studies on transport from <span class="hlt">ocean</span> vortices typically rely on Eulerian identification methods, in which vortices are identified by selecting closed contours of Eulerian fields (e.g. sea surface height, or the Okubo-Weiss parameter) that satisfy geometric criteria and anomaly thresholds. In contrast, recent studies employ Lagrangian analysis of virtual particle trajectories initialized within the selected Eulerian contours, revealing significant discrepancies between the advection of the contour's material interior and the evolution of the Eulerian field contour. This work investigates the global mass and tracer transport associated with materially coherent surface <span class="hlt">ocean</span> vortices. Further, it addresses differences between Eulerian and Lagrangian analyses for the detection of vortices. To do so, we use GFDL's CM2.6 coupled <span class="hlt">climate</span> <span class="hlt">model</span> with 5-10km horizontal grid spacing. We identify coherent vortices in CM2.6 by implementing the Rotationally Coherent Lagrangian Vortex (RCLV) framework, which recently emerged from dynamical systems theory. This approach involves the numerical advection of millions of Lagrangian particles and guarantees material coherence by construction. We compute the statistics, spatial distribution, and lifetimes of coherent vortices in addition to calculating the associated mass and tracer transports. We offer compelling evidence that Eulerian vortex methods are poorly suited to answer questions of mass and tracer transport.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6303M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6303M"><span>Baroclinic stabilization effect of the Atlantic-Arctic water exchange simulated by the eddy-permitting <span class="hlt">ocean</span> <span class="hlt">model</span> and global atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moshonkin, Sergey; Bagno, Alexey; Gritsun, Andrey; Gusev, Anatoly</p> <p>2017-04-01</p> <p>Numerical experiments were performed with the global atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span> INMCM5 (for version of the international project CMIP6, resolution for atmosphere is 2°x1.5°, 21 level) and with the three-dimensional, free surface, sigma coordinate eddy-permitting <span class="hlt">ocean</span> circulation <span class="hlt">model</span> for Atlantic (from 30°S) - Arctic and Bering sea domain (0.25 degrees resolution, Institute of Numerical Mathematics <span class="hlt">Ocean</span> <span class="hlt">Model</span> or INMOM). Spatial resolution of the INMCM5 <span class="hlt">oceanic</span> component is 0.5°x0.25°. Both <span class="hlt">models</span> have 40 s-levels in <span class="hlt">ocean</span>. Previously, the simulations were carried out for INMCM5 to generate <span class="hlt">climatic</span> system stable state. Then <span class="hlt">model</span> was run for 180 years. In the experiment with INMOM, CORE-II data for 1948-2009 were used. As the goal for comparing results of two these numerical <span class="hlt">models</span>, we selected evolution of the density and velocity anomalies in the 0-300m active <span class="hlt">ocean</span> layer near Fram Strait in the Greenland Sea, where <span class="hlt">oceanic</span> cyclonic circulation influences Atlantic-Arctic water exchange. Anomalies were count without <span class="hlt">climatic</span> seasonal cycle for time scales smaller than 30 years. We use Singular Value Decomposition analysis (SVD) for density-velocity anomalies with time lag from minus one to six months. Both <span class="hlt">models</span> perform identical stable physical result. They reveal that changes of heat and salt transports by West Spitsbergen and East Greenland currents, caused by atmospheric forcing, produce the baroclinic modes of velocity anomalies in 0-300m layer, thereby stabilizing <span class="hlt">ocean</span> response on the atmospheric forcing, which stimulates keeping water exchange between the North Atlantic and Arctic <span class="hlt">Ocean</span> at the certain climatological level. The first SVD-mode of density-velocity anomalies is responsible for the cyclonic circulation variability. The second and third SVD-modes stabilize existing <span class="hlt">ocean</span> circulation by the anticyclonic vorticity generation. The second and third SVD-modes give 35% of the input to the total dispersion of density anomalies and 16-18% of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53A1009H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53A1009H"><span>Stochastic <span class="hlt">Ocean</span> Eddy Perturbations in a Coupled General Circulation <span class="hlt">Model</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howe, N.; Williams, P. D.; Gregory, J. M.; Smith, R. S.</p> <p>2014-12-01</p> <p>High-resolution <span class="hlt">ocean</span> <span class="hlt">models</span>, which are eddy permitting and resolving, require large computing resources to produce centuries worth of data. Also, some previous studies have suggested that increasing resolution does not necessarily solve the problem of unresolved scales, because it simply introduces a new set of unresolved scales. Applying stochastic parameterisations to <span class="hlt">ocean</span> <span class="hlt">models</span> is one solution that is expected to improve the representation of small-scale (eddy) effects without increasing run-time. Stochastic parameterisation has been shown to have an impact in atmosphere-only <span class="hlt">models</span> and idealised <span class="hlt">ocean</span> <span class="hlt">models</span>, but has not previously been studied in <span class="hlt">ocean</span> general circulation <span class="hlt">models</span>. Here we apply simple stochastic perturbations to the <span class="hlt">ocean</span> temperature and salinity tendencies in the low-resolution coupled <span class="hlt">climate</span> <span class="hlt">model</span>, FAMOUS. The stochastic perturbations are implemented according to T(t) = T(t-1) + (ΔT(t) + ξ(t)), where T is temperature or salinity, ΔT is the corresponding deterministic increment in one time step, and ξ(t) is Gaussian noise. We use high-resolution HiGEM data coarse-grained to the FAMOUS grid to provide information about the magnitude and spatio-temporal correlation structure of the noise to be added to the lower resolution <span class="hlt">model</span>. Here we present results of adding white and red noise, showing the impacts of an additive stochastic perturbation on mean <span class="hlt">climate</span> state and variability in an AOGCM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.U12B..03R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.U12B..03R"><span><span class="hlt">Ocean</span> Drilling Program Records of the Last Five Million Years: A View of the <span class="hlt">Ocean</span> and <span class="hlt">Climate</span> System During a Warm Period and a Major <span class="hlt">Climate</span> Transition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ravelo, A. C.</p> <p>2003-12-01</p> <p>The warm Pliocene (4.7 to 3.0 Ma), the most recent period in Earth's history when global equilibrium <span class="hlt">climate</span> was warmer than today, provides the opportunity to understand what role the components of the <span class="hlt">climate</span> system that have a long timescale of response (cryosphere and <span class="hlt">ocean</span>) play in determining globally warm conditions, and in forcing the major global <span class="hlt">climate</span> cooling after 3.0 Ma. Because sediments of this age are well preserved in many locations in the world's <span class="hlt">oceans</span>, we can potentially study this warm period in detail. One major accomplishment of the <span class="hlt">Ocean</span> Drilling Program is the recovery of long continuous sediment sequences from all <span class="hlt">ocean</span> basins that span the last 5.0 Ma. Dozens of paleoceanographers have generated <span class="hlt">climate</span> records from these sediments. I will present a synthesis of these data to provide a global picture of the Pliocene warm period, the transition to the cold Pleistocene period, and changes in <span class="hlt">climate</span> sensitivity related to this transition. In the Pliocene warm period, tropical sea surface temperature (SST) and global <span class="hlt">climate</span> patterns suggest average conditions that resemble modern El Ni¤os, and deep <span class="hlt">ocean</span> reconstructions indicate enhanced thermohaline overturning and reduced density and nutrient stratification. The data indicate that the warm conditions were not related to tectonic changes in <span class="hlt">ocean</span> basin shape compared to today, rather they reflect the long term adjustment of the <span class="hlt">climate</span> system to stronger than modern radiative forcing. The warm Pliocene to cold Pleistocene transition provides an opportunity to study the feedbacks of various components of the <span class="hlt">climate</span> system. The marked onset of significant Northern hemisphere glaciation (NHG) at 2.75 Ma occurred in concert with a reduction in deep <span class="hlt">ocean</span> ventilation, but cooling in subtropical and tropical regions was more gradual until Walker circulation was established in a major step at 2.0 Ma. Thus, regional high latitude ice albedo feedbacks, rather than low latitude processes, must</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70099203','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70099203"><span>Advances in a distributed approach for <span class="hlt">ocean</span> <span class="hlt">model</span> data interoperability</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Signell, Richard P.; Snowden, Derrick P.</p> <p>2014-01-01</p> <p>An infrastructure for earth science data is emerging across the globe based on common data <span class="hlt">models</span> and web services. As we evolve from custom file formats and web sites to standards-based web services and tools, data is becoming easier to distribute, find and retrieve, leaving more time for science. We describe recent advances that make it easier for <span class="hlt">ocean</span> <span class="hlt">model</span> providers to share their data, and for users to search, access, analyze and visualize <span class="hlt">ocean</span> data using MATLAB® and Python®. These include a technique for <span class="hlt">modelers</span> to create aggregated, <span class="hlt">Climate</span> and Forecast (CF) metadata convention datasets from collections of non-standard Network Common Data Form (NetCDF) output files, the capability to remotely access data from CF-1.6-compliant NetCDF files using the Open Geospatial Consortium (OGC) Sensor Observation Service (SOS), a metadata standard for unstructured grid <span class="hlt">model</span> output (UGRID), and tools that utilize both CF and UGRID standards to allow interoperable data search, browse and access. We use examples from the U.S. Integrated <span class="hlt">Ocean</span> Observing System (IOOS®) Coastal and <span class="hlt">Ocean</span> <span class="hlt">Modeling</span> Testbed, a project in which <span class="hlt">modelers</span> using both structured and unstructured grid <span class="hlt">model</span> output needed to share their results, to compare their results with other <span class="hlt">models</span>, and to compare <span class="hlt">models</span> with observed data. The same techniques used here for <span class="hlt">ocean</span> <span class="hlt">modeling</span> output can be applied to atmospheric and <span class="hlt">climate</span> <span class="hlt">model</span> output, remote sensing data, digital terrain and bathymetric data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5559419','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5559419"><span>High-latitude <span class="hlt">ocean</span> ventilation and its role in Earth's <span class="hlt">climate</span> transitions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>MacGilchrist, Graeme A. ; Brown, Peter J.; Evans, D. Gwyn; Meijers, Andrew J. S.; Zika, Jan D.</p> <p>2017-01-01</p> <p>The processes regulating <span class="hlt">ocean</span> ventilation at high latitudes are re-examined based on a range of observations spanning all scales of <span class="hlt">ocean</span> circulation, from the centimetre scales of turbulence to the basin scales of gyres. It is argued that high-latitude <span class="hlt">ocean</span> ventilation is controlled by mechanisms that differ in fundamental ways from those that set the overturning circulation. This is contrary to the assumption of broad equivalence between the two that is commonly adopted in interpreting the role of the high-latitude <span class="hlt">oceans</span> in Earth's <span class="hlt">climate</span> transitions. Illustrations of how recognizing this distinction may change our view of the <span class="hlt">ocean</span>'s role in the <span class="hlt">climate</span> system are offered. This article is part of the themed issue ‘<span class="hlt">Ocean</span> ventilation and deoxygenation in a warming world’. PMID:28784714</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GPC....42..107G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GPC....42..107G"><span>The evolution of a coupled ice shelf-<span class="hlt">ocean</span> system under different <span class="hlt">climate</span> states</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grosfeld, Klaus; Sandhäger, Henner</p> <p>2004-07-01</p> <p>Based on a new approach for coupled applications of an ice shelf <span class="hlt">model</span> and an <span class="hlt">ocean</span> general circulation <span class="hlt">model</span>, we investigate the evolution of an ice shelf-<span class="hlt">ocean</span> system and its sensitivity to changed <span class="hlt">climatic</span> boundary conditions. Combining established 3D <span class="hlt">models</span> into a coupled <span class="hlt">model</span> system enabled us to study the reaction and feedbacks of each component to changes at their interface, the ice shelf base. After calculating the dynamics for prescribed initial ice shelf and bathymetric geometries, the basal mass balance determines the system evolution. In order to explore possible developments for given boundary conditions, an idealized geometry has been chosen, reflecting basic features of the Filchner-Ronne Ice Shelf, Antarctica. The <span class="hlt">model</span> system is found to be especially sensitive in regions where high ablation or accretion rates occur. Ice Shelf Water formation as well as the build up of a marine ice body, resulting from accretion of marine ice, is simulated, indicating strong interaction processes. To improve consistency between <span class="hlt">modeled</span> and observed ice shelf behavior, we incorporate the typical cycle of steady ice front advance and sudden retreat due to tabular iceberg calving in our time-dependent simulations. Our basic hypothesis is that iceberg break off is associated with abrupt crack propagation along elongated anomalies of the inherent stress field of the ice body. This new concept yields glaciologically plausible results and represents an auspicious basis for the development of a thorough calving criterion. Experiments under different <span class="hlt">climatic</span> conditions (<span class="hlt">ocean</span> warming of 0.2 and 0.5 °C and doubled surface accumulation rates) show the coupled <span class="hlt">model</span> system to be sensitive especially to <span class="hlt">ocean</span> warming. Increased basal melt rates of 100% for the 0.5 °C <span class="hlt">ocean</span> warming scenario and an asymmetric development of ice shelf thicknesses suggest a high vulnerability of ice shelf regions, which represent pivotal areas between the Antarctic Ice Sheet and the Southern</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1233519-collaborative-project-understanding-climate-model-biases-tropical-atlantic-impact-simulations-extreme-climate-events','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1233519-collaborative-project-understanding-climate-model-biases-tropical-atlantic-impact-simulations-extreme-climate-events"><span>Collaborative Project: Understanding <span class="hlt">Climate</span> <span class="hlt">Model</span> Biases in Tropical Atlantic and Their Impact on Simulations of Extreme <span class="hlt">Climate</span> Events</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang, Ping</p> <p></p> <p>Recent studies have revealed that among all the tropical <span class="hlt">oceans</span>, the tropical Atlantic has experienced the most pronounced warming trend over the 20th century. Many extreme <span class="hlt">climate</span> events affecting the U.S., such as hurricanes, severe precipitation and drought events, are influenced by conditions in the Gulf of Mexico and the Atlantic <span class="hlt">Ocean</span>. It is therefore imperative to have accurate simulations of the <span class="hlt">climatic</span> mean and variability in the Atlantic region to be able to make credible projections of future <span class="hlt">climate</span> change affecting the U.S. and other countries adjoining the Atlantic <span class="hlt">Ocean</span>. Unfortunately, almost all global <span class="hlt">climate</span> <span class="hlt">models</span> exhibit large biasesmore » in their simulations of tropical Atlantic <span class="hlt">climate</span>. The atmospheric convection simulation errors in the Amazon region and the associated errors in the trade wind simulations are hypothesized to be a leading cause of the tropical Atlantic biases in <span class="hlt">climate</span> <span class="hlt">models</span>. As global <span class="hlt">climate</span> <span class="hlt">models</span> have resolutions that are too coarse to resolve some of the atmospheric and <span class="hlt">oceanic</span> processes responsible for the <span class="hlt">model</span> biases, we propose to use a high-resolution coupled regional <span class="hlt">climate</span> <span class="hlt">model</span> (CRCM) framework to address the tropical bias issue. We propose to combine the expertise in tropical coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">modeling</span> at Texas A&M University (TAMU) and the coupled land-atmosphere <span class="hlt">modeling</span> expertise at Pacific Northwest National Laboratory (PNNL) to develop a comprehensive CRCM for the Atlantic sector within a general and flexible <span class="hlt">modeling</span> framework. The atmospheric component of the CRCM will be the NCAR WRF <span class="hlt">model</span> and the <span class="hlt">oceanic</span> component will be the Rutgers/UCLA ROMS. For the land component, we will use CLM modified at PNNL to include more detailed representations of vegetation and soil hydrology processes. The combined TAMU-PNNL CRCM <span class="hlt">model</span> will be used to simulate the Atlantic <span class="hlt">climate</span>, and the associated land-atmosphere-<span class="hlt">ocean</span> interactions at a horizontal resolution of 9 km or finer. A particular focus of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011961','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011961"><span>State of <span class="hlt">Climate</span> 2011 - Global <span class="hlt">Ocean</span> Phytoplankton</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Siegel, D. A.; Antoine, D.; Behrenfeld, M. J.; d'Andon, O. H. Fanton; Fields, E.; Franz, B. A.; Goryl, P.; Maritorena, S.; McClain, C. R.; Wang, M.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20120011961'); toggleEditAbsImage('author_20120011961_show'); toggleEditAbsImage('author_20120011961_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20120011961_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20120011961_hide"></p> <p>2012-01-01</p> <p>Phytoplankton photosynthesis in the sun lit upper layer of the global <span class="hlt">ocean</span> is the overwhelmingly dominant source of organic matter that fuels marine ecosystems. Phytoplankton contribute roughly half of the global (land and <span class="hlt">ocean</span>) net primary production (NPP; gross photosynthesis minus plant respiration) and phytoplankton carbon fixation is the primary conduit through which atmospheric CO2 concentrations interact with the <span class="hlt">ocean</span> s carbon cycle. Phytoplankton productivity depends on the availability of sunlight, macronutrients (e.g., nitrogen, phosphorous), and micronutrients (e.g., iron), and thus is sensitive to <span class="hlt">climate</span>-driven changes in the delivery of these resources to the euphotic zone</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015727','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015727"><span>The role of <span class="hlt">ocean</span> <span class="hlt">climate</span> data in operational Naval oceanography</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chesbrough, Radm G.</p> <p>1992-01-01</p> <p>Local application of global-scale <span class="hlt">models</span> describes the U.S. Navy's basic philosophy for operational oceanography in support of fleet operations. Real-time data, climatologies, coupled air/<span class="hlt">ocean</span> <span class="hlt">models</span>, and large scale computers are the essential components of the Navy's system for providing the war fighters with the performance predictions and tactical decision aids they need to operate safely and efficiently. In peacetime, these oceanographic predictions are important for safety of navigation and flight. The paucity and uneven distribution of real-time data mean we have to fall back on climatology to provide the basic data to operate our <span class="hlt">models</span>. The Navy is both a producer and user of climatologies; it provides observations to the national archives and in turn employs data from these archives to establish data bases. Suggestions for future improvements to <span class="hlt">ocean</span> <span class="hlt">climate</span> data are offered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A13L..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A13L..08S"><span><span class="hlt">Climate</span> Process Team "Representing calving and iceberg dynamics in global <span class="hlt">climate</span> <span class="hlt">models</span>"</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sergienko, O. V.; Adcroft, A.; Amundson, J. M.; Bassis, J. N.; Hallberg, R.; Pollard, D.; Stearns, L. A.; Stern, A. A.</p> <p>2016-12-01</p> <p>Iceberg calving accounts for approximately 50% of the ice mass loss from the Greenland and Antarctic ice sheets. By changing a glacier's geometry, calving can also significantly perturb the glacier's stress-regime far upstream of the grounding line. This process can enhance discharge of ice across the grounding line. Once calved, icebergs drift into the open <span class="hlt">ocean</span> where they melt, injecting freshwater to the <span class="hlt">ocean</span> and affecting the large-scale <span class="hlt">ocean</span> circulation. The spatial redistribution of the freshwater flux have strong impact on sea-ice formation and its spatial variability. A <span class="hlt">Climate</span> Process Team "Representing calving and iceberg dynamics in global <span class="hlt">climate</span> <span class="hlt">models</span>" was established in the fall 2014. The major objectives of the CPT are: (1) develop parameterizations of calving processes that are suitable for continental-scale ice-sheet <span class="hlt">models</span> that simulate the evolution of the Antarctic and Greenland ice sheets; (2) compile the data sets of the glaciological and oceanographic observations that are necessary to test, validate and constrain the developed parameterizations and <span class="hlt">models</span>; (3) develop a physically based iceberg component for inclusion in the large-scale <span class="hlt">ocean</span> circulation <span class="hlt">model</span>. Several calving parameterizations based suitable for various glaciological settings have been developed and implemented in a continental-scale ice sheet <span class="hlt">model</span>. Simulations of the present-day Antarctic and Greenland ice sheets show that the ice-sheet geometric configurations (thickness and extent) are sensitive to the calving process. In order to guide the development as well as to test calving parameterizations, available observations (of various kinds) have been compiled and organized into a database. Monthly estimates of iceberg distribution around the coast of Greenland have been produced with a goal of constructing iceberg size distribution and probability functions for iceberg occurrence in particular regions. A physically based iceberg <span class="hlt">model</span> component was used in a GFDL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.U54A..04R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.U54A..04R"><span>The Once and Future Battles of Thor and the Midgard Serpent (or the Southern <span class="hlt">Ocean</span>'s Role in <span class="hlt">Climate</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, J. L.</p> <p>2017-12-01</p> <p>Floats deployed by oceanographers are giving us all ringside seats to the epic battle between the wind and the deep <span class="hlt">ocean</span> around Antarctica which will determine the rate of global atmospheric warming over the next century. The poleward-shift and intensification of the Southern Hemisphere westerly winds has been shown to maintain the connection between the surface <span class="hlt">ocean</span> and the atmosphere with the deep <span class="hlt">ocean</span> even as the surface <span class="hlt">ocean</span> warms. This "doorway" allows the vast deep <span class="hlt">ocean</span> reservoir to play a significant role in the transient global <span class="hlt">climate</span> response to increasing atmospheric greenhouse gases. Coupled <span class="hlt">climate</span> and earth system <span class="hlt">models</span> at low and high resolution all simulate poleward-shifted and intensified Southern Hemisphere surface westerly winds when subjected to an atmospheric carbon dioxide doubling. Comparisons of these simulations reveal how stratification, resolution and eddies affect the transient global <span class="hlt">climate</span> response to increasing atmospheric greenhouse gases - and our collective fate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC21E0985O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC21E0985O"><span>Uncertainty in Earth System <span class="hlt">Models</span>: Benchmarks for <span class="hlt">Ocean</span> <span class="hlt">Model</span> Performance and Validation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ogunro, O. O.; Elliott, S.; Collier, N.; Wingenter, O. W.; Deal, C.; Fu, W.; Hoffman, F. M.</p> <p>2017-12-01</p> <p>The mean <span class="hlt">ocean</span> CO2 sink is a major component of the global carbon budget, with marine reservoirs holding about fifty times more carbon than the atmosphere. Phytoplankton play a significant role in the net carbon sink through photosynthesis and drawdown, such that about a quarter of anthropogenic CO2 emissions end up in the <span class="hlt">ocean</span>. Biology greatly increases the efficiency of marine environments in CO2 uptake and ultimately reduces the impact of the persistent rise in atmospheric concentrations. However, a number of challenges remain in appropriate representation of marine biogeochemical processes in Earth System <span class="hlt">Models</span> (ESM). These threaten to undermine the community effort to quantify seasonal to multidecadal variability in <span class="hlt">ocean</span> uptake of atmospheric CO2. In a bid to improve analyses of marine contributions to <span class="hlt">climate</span>-carbon cycle feedbacks, we have developed new analysis methods and biogeochemistry metrics as part of the International <span class="hlt">Ocean</span> <span class="hlt">Model</span> Benchmarking (IOMB) effort. Our intent is to meet the growing diagnostic and benchmarking needs of <span class="hlt">ocean</span> biogeochemistry <span class="hlt">models</span>. The resulting software package has been employed to validate DOE <span class="hlt">ocean</span> biogeochemistry results by comparison with observational datasets. Several other international <span class="hlt">ocean</span> <span class="hlt">models</span> contributing results to the fifth phase of the Coupled <span class="hlt">Model</span> Intercomparison Project (CMIP5) were analyzed simultaneously. Our comparisons suggest that the biogeochemical processes determining CO2 entry into the global <span class="hlt">ocean</span> are not well represented in most ESMs. Polar regions continue to show notable biases in many critical biogeochemical and physical oceanographic variables. Some of these disparities could have first order impacts on the conversion of atmospheric CO2 to organic carbon. In addition, single forcing simulations show that the current <span class="hlt">ocean</span> state can be partly explained by the uptake of anthropogenic emissions. Combined effects of two or more of these forcings on <span class="hlt">ocean</span> biogeochemical cycles and ecosystems</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870056085&hterms=oceans+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Doceans%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870056085&hterms=oceans+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Doceans%2Bclimate%2Bchanges"><span><span class="hlt">Climate</span> warming due to increasing atmospheric CO2 - Simulations with a multilayer coupled atmosphere-<span class="hlt">ocean</span> seasonal energy balance <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Peng; Chou, Ming-Dah; Arking, Albert</p> <p>1987-01-01</p> <p>The transient response of the <span class="hlt">climate</span> to increasing CO2 is studied using a modified version of the multilayer energy balance <span class="hlt">model</span> of Peng et al. (1982). The main characteristics of the <span class="hlt">model</span> are described. Latitudinal and seasonal distributions of planetary albedo, latitude-time distributions of zonal mean temperatures, and latitudinal distributions of evaporation, water vapor transport, and snow cover generated from the <span class="hlt">model</span> and derived from actual observations are analyzed and compared. It is observed that in response to an atmospheric doubling of CO2, the <span class="hlt">model</span> reaches within 1/e of the equilibrium response of global mean surface temperature in 9-35 years for the probable range of vertical heat diffusivity in the <span class="hlt">ocean</span>. For CO2 increases projected by the National Research Council (1983), the <span class="hlt">model</span>'s transient response in annually and globally averaged surface temperatures is 60-75 percent of the corresponding equilibrium response, and the disequilibrium increases with increasing heat diffusivity of the <span class="hlt">ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA482695','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA482695"><span>The ARGO Project: Global <span class="hlt">Ocean</span> Observations for Understanding and Prediction of <span class="hlt">Climate</span> Variability. Report for Calendar Year 2004</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2004-01-01</p> <p>international Argo practices. Data appropriate for research applications and for comparison with <span class="hlt">climate</span> change <span class="hlt">models</span> are not available for several...global <span class="hlt">ocean</span> heat and fresh water storage and the detection and attribution of <span class="hlt">climate</span> change . These presentations can be accessed at http...stresses on <span class="hlt">ocean</span> ecosystems have serious consequences, and sometimes dramatic ones, such as coral reef bleaching . In the future, the impacts of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUSMGC51A..04D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUSMGC51A..04D"><span>Arctic <span class="hlt">Ocean</span> <span class="hlt">Model</span> Intercomparison Using Sound Speed</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dukhovskoy, D. S.; Johnson, M. A.</p> <p>2002-05-01</p> <p>The monthly and annual means from three Arctic <span class="hlt">ocean</span> - sea ice <span class="hlt">climate</span> <span class="hlt">model</span> simulations are compared for the period 1979-1997. Sound speed is used to integrate <span class="hlt">model</span> outputs of temperature and salinity along a section between Barrow and Franz Josef Land. A statistical approach is used to test for differences among the three <span class="hlt">models</span> for two basic data subsets. We integrated and then analyzed an upper layer between 2 m - 50 m, and also a deep layer from 500 m to the bottom. The deep layer is characterized by low time-variability. No high-frequency signals appear in the deep layer having been filtered out in the upper layer. There is no seasonal signal in the deep layer and the monthly means insignificantly oscillate about the long-period mean. For the deep <span class="hlt">ocean</span> the long-period mean can be considered quasi-constant, at least within the 19 year period of our analysis. Thus we assumed that the deep <span class="hlt">ocean</span> would be the best choice for comparing the means of the <span class="hlt">model</span> outputs. The upper (mixed) layer was chosen to contrast the deep layer dynamics. There are distinct seasonal and interannual signals in the sound speed time series in this layer. The mixed layer is a major link in the <span class="hlt">ocean</span> - air interaction mechanism. Thus, different mean states of the upper layer in the <span class="hlt">models</span> might cause different responses in other components of the Arctic <span class="hlt">climate</span> system. The upper layer also strongly reflects any differences in atmosphere forcing. To compare data from the three <span class="hlt">models</span> we have used a one-way t-test for the population mean, the Wilcoxon one-sample signed-rank test (when the requirement of normality of tested data is violated), and one-way ANOVA method and F-test to verify our hypothesis that the <span class="hlt">model</span> outputs have the same mean sound speed. The different statistical approaches have shown that all <span class="hlt">models</span> have different mean characteristics of the deep and upper layers of the Arctic <span class="hlt">Ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28784714','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28784714"><span>High-latitude <span class="hlt">ocean</span> ventilation and its role in Earth's <span class="hlt">climate</span> transitions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Naveira Garabato, Alberto C; MacGilchrist, Graeme A; Brown, Peter J; Evans, D Gwyn; Meijers, Andrew J S; Zika, Jan D</p> <p>2017-09-13</p> <p>The processes regulating <span class="hlt">ocean</span> ventilation at high latitudes are re-examined based on a range of observations spanning all scales of <span class="hlt">ocean</span> circulation, from the centimetre scales of turbulence to the basin scales of gyres. It is argued that high-latitude <span class="hlt">ocean</span> ventilation is controlled by mechanisms that differ in fundamental ways from those that set the overturning circulation. This is contrary to the assumption of broad equivalence between the two that is commonly adopted in interpreting the role of the high-latitude <span class="hlt">oceans</span> in Earth's <span class="hlt">climate</span> transitions. Illustrations of how recognizing this distinction may change our view of the <span class="hlt">ocean</span>'s role in the <span class="hlt">climate</span> system are offered.This article is part of the themed issue '<span class="hlt">Ocean</span> ventilation and deoxygenation in a warming world'. © 2017 The Authors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRD..11220105M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRD..11220105M"><span>Manifestation of remote response over the equatorial Pacific in a <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Misra, Vasubandhu; Marx, L.</p> <p>2007-10-01</p> <p>In this paper we examine the simulations over the tropical Pacific <span class="hlt">Ocean</span> from long-term simulations of two different versions of the Center for <span class="hlt">Ocean</span>-Land-Atmosphere Studies (COLA) coupled <span class="hlt">climate</span> <span class="hlt">model</span> that have a different global distribution of the inversion clouds. We find that subtle changes made to the numerics of an empirical parameterization of the inversion clouds can result in a significant change in the coupled <span class="hlt">climate</span> of the equatorial Pacific <span class="hlt">Ocean</span>. In one coupled simulation of this study we enforce a simple linear spatial filtering of the diagnostic inversion clouds to ameliorate its spatial incoherency (as a result of the Gibbs effect) while in the other we conduct no such filtering. It is found from the comparison of these two simulations that changing the distribution of the shallow inversion clouds prevalent in the subsidence region of the subtropical high over the eastern <span class="hlt">oceans</span> in this manner has a direct bearing on the surface wind stress through surface pressure modifications. The SST in the warm pool region responds to this modulation of the wind stress, thus affecting the convective activity over the warm pool region and also the large-scale Walker and Hadley circulation. The interannual variability of SST in the eastern equatorial Pacific <span class="hlt">Ocean</span> is also modulated by this change to the inversion clouds. Consequently, this sensitivity has a bearing on the midlatitude height response. The same set of two experiments were conducted with the respective versions of the atmosphere general circulation <span class="hlt">model</span> uncoupled to the <span class="hlt">ocean</span> general circulation <span class="hlt">model</span> but forced with observed SST to demonstrate that this sensitivity of the mean <span class="hlt">climate</span> of the equatorial Pacific <span class="hlt">Ocean</span> is unique to the coupled <span class="hlt">climate</span> <span class="hlt">model</span> where atmosphere, <span class="hlt">ocean</span> and land interact. Therefore a strong case is made for adopting coupled <span class="hlt">ocean</span>-land-atmosphere framework to develop <span class="hlt">climate</span> <span class="hlt">models</span> as against the usual practice of developing component <span class="hlt">models</span> independent of each other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002118','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002118"><span>The Effects of Interactive Stratospheric Chemistry on Antarctic and Southern <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Change in an AOGCM</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Feng; Newman, Paul; Pawson, Steven; Waugh, Darryn</p> <p>2014-01-01</p> <p>Stratospheric ozone depletion has played a dominant role in driving Antarctic <span class="hlt">climate</span> change in the last decades. In order to capture the stratospheric ozone forcing, many coupled atmosphere-<span class="hlt">ocean</span> general circulation <span class="hlt">models</span> (AOGCMs) prescribe the Antarctic ozone hole using monthly and zonally averaged ozone field. However, the prescribed ozone hole has a high ozone bias and lacks zonal asymmetry. The impacts of these biases on <span class="hlt">model</span> simulations, particularly on Southern <span class="hlt">Ocean</span> and the Antarctic sea ice, are not well understood. The purpose of this study is to determine the effects of using interactive stratospheric chemistry instead of prescribed ozone on Antarctic and Southern <span class="hlt">Ocean</span> <span class="hlt">climate</span> change in an AOGCM. We compare two sets of ensemble simulations for the 1960-2010 period using different versions of the Goddard Earth Observing System 5 - AOGCM: one with interactive stratospheric chemistry, and the other with prescribed monthly and zonally averaged ozone and 6 other stratospheric radiative species calculated from the interactive chemistry simulations. Consistent with previous studies using prescribed sea surface temperatures and sea ice concentrations, the interactive chemistry runs simulate a deeper Antarctic ozone hole and consistently larger changes in surface pressure and winds than the prescribed ozone runs. The use of a coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span> in this study enables us to determine the impact of these surface changes on Southern <span class="hlt">Ocean</span> circulation and Antarctic sea ice. The larger surface wind trends in the interactive chemistry case lead to larger Southern <span class="hlt">Ocean</span> circulation trends with stronger changes in northerly and westerly surface flow near the Antarctica continent and stronger upwelling near 60S. Using interactive chemistry also simulates a larger decrease of sea ice concentrations. Our results highlight the importance of using interactive chemistry in order to correctly capture the influences of stratospheric ozone depletion on <span class="hlt">climate</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C23A1213G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C23A1213G"><span>The frequency response of a coupled ice sheet-ice shelf-<span class="hlt">ocean</span> system to <span class="hlt">climate</span> forcing variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goldberg, D.; Snow, K.; Jordan, J. R.; Holland, P.; Arthern, R. J.</p> <p>2017-12-01</p> <p>Changes at the West Antarctic ice-<span class="hlt">ocean</span> boundary in recent decades has triggered significant increases in the regions contribution to global sea-level rise, coincident with large scale, and in some cases potentially unstable, grounding line retreat. Much of the induced change is thought to be driven by fluctuations in the <span class="hlt">oceanic</span> heat available at the ice-<span class="hlt">ocean</span> boundary, transported on-shelf via warm Circumpolar Deep Water (CDW). However, the processes in which <span class="hlt">ocean</span> heat drives ice-sheet loss remains poorly understood, with observational studies routinely hindered by the extreme environment notorious to the Antarctic region. In this study we apply a novel synchronous coupled ice-<span class="hlt">ocean</span> <span class="hlt">model</span>, developed within the MITgcm, and are thus able to provide detailed insight into the impacts of short time scale (interannual to decadal) <span class="hlt">climate</span> variability and feedbacks within the ice-<span class="hlt">ocean</span> system. Feedbacks and response are assessed in an idealised ice-sheet/<span class="hlt">ocean</span>-cavity configuration in which the far field <span class="hlt">ocean</span> condition is adjusted to emulate periodic <span class="hlt">climate</span> variability patterns. We reveal a non-linear response of the ice-sheet to periodic variations in thermocline depth. These non-linearities illustrate the heightened sensitivity of fast flowing ice-shelves to periodic perturbations in heat fluxes occurring at interannual and decadal time scales. The results thus highlight how small perturbations in variable <span class="hlt">climate</span> forcing, like that of ENSO, may trigger large changes in ice-sheet response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A24E..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A24E..03S"><span>Comparison of MERRA-2 and ECCO-v4 <span class="hlt">ocean</span> surface heat fluxes: Consequences of different forcing feedbacks on <span class="hlt">ocean</span> circulation and implications for <span class="hlt">climate</span> data assimilation.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strobach, E.; Molod, A.; Menemenlis, D.; Forget, G.; Hill, C. N.; Campin, J. M.; Heimbach, P.</p> <p>2017-12-01</p> <p>Forcing <span class="hlt">ocean</span> <span class="hlt">models</span> with reanalysis data is a common practice in <span class="hlt">ocean</span> <span class="hlt">modeling</span>. As part of this practice, prescribed atmospheric state variables and interactive <span class="hlt">ocean</span> SST are used to calculate fluxes between the <span class="hlt">ocean</span> and the atmosphere. When forcing an <span class="hlt">ocean</span> <span class="hlt">model</span> with reanalysis fields, errors in the reanalysis data, errors in the <span class="hlt">ocean</span> <span class="hlt">model</span> and errors in the forcing formulation will generate a different solution compared to other <span class="hlt">ocean</span> reanalysis solutions (which also have their own errors). As a first step towards a consistent coupled <span class="hlt">ocean</span>-atmosphere reanalysis, we compare surface heat fluxes from a state-of-the-art atmospheric reanalysis, the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), to heat fluxes from a state-of-the-art <span class="hlt">oceanic</span> reanalysis, the Estimating the Circulation and <span class="hlt">Climate</span> of the <span class="hlt">Ocean</span> Version 4, Release 2 (ECCO-v4). Then, we investigate the errors associated with the MITgcm <span class="hlt">ocean</span> <span class="hlt">model</span> in its ECCO-v4 <span class="hlt">ocean</span> reanalysis configuration (1992-2011) when it is forced with MERRA-2 atmospheric reanalysis fields instead of with the ECCO-v4 adjoint optimized ERA-interim state variables. This is done by forcing ECCO-v4 <span class="hlt">ocean</span> with and without feedbacks from MERRA-2 related to turbulent fluxes of heat and moisture and the outgoing long wave radiation. In addition, we introduce an intermediate forcing method that includes only the feedback from the interactive outgoing long wave radiation. The resulting <span class="hlt">ocean</span> circulation is compared with ECCO-v4 reanalysis and in-situ observations. We show that, without feedbacks, imbalances in the energy and the hydrological cycles of MERRA-2 (which are directly related to the fact it was created without interactive <span class="hlt">ocean</span>) result in considerable SST drifts and a large reduction in sea level. The bulk formulae and interactive outgoing long wave radiation, although providing air-sea feedbacks and reducing <span class="hlt">model</span>-data misfit, strongly relax the <span class="hlt">ocean</span> to observed SST and may result in</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A14F..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A14F..04S"><span>Coupled Regional <span class="hlt">Ocean</span>-Atmosphere <span class="hlt">Modeling</span> of the Mount Pinatubo Impact on the Red Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stenchikov, G. L.; Osipov, S.</p> <p>2017-12-01</p> <p>The 1991 eruption of Mount Pinatubo had dramatic effects on the regional <span class="hlt">climate</span> in the Middle East. Though acknowledged, these effects have not been thoroughly studied. To fill this gap and to advance understanding of the mechanisms that control variability in the Middle East's regional <span class="hlt">climate</span>, we simulated the impact of the 1991 Pinatubo eruption using a regional coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">modeling</span> system set for the Middle East and North Africa (MENA) domain. We used the Coupled <span class="hlt">Ocean</span>-Atmosphere-Wave-Sediment Transport (COAWST) framework, which couples the Weather Research and Forecasting <span class="hlt">Model</span> (WRF) <span class="hlt">model</span> with the Regional <span class="hlt">Oceanic</span> <span class="hlt">Modeling</span> System (ROMS). We modified the WRF <span class="hlt">model</span> to account for the radiative effect of volcanic aerosols. Our coupled <span class="hlt">ocean</span>-atmosphere simulations verified by available observations revealed strong perturbations in the energy balance of the Red Sea, which drove thermal and circulation responses. Our <span class="hlt">modeling</span> approach allowed us to separate changes in the atmospheric circulation caused by the impact of the volcano from direct regional radiative cooling from volcanic aerosols. The atmospheric circulation effect was significantly stronger than the direct volcanic aerosols effect. We found that the Red Sea response to the Pinatubo eruption was stronger and qualitatively different from that of the global <span class="hlt">ocean</span> system. Our results suggest that major volcanic eruptions significantly affect the <span class="hlt">climate</span> in the Middle East and the Red Sea and should be carefully taken into account in assessments of long-term <span class="hlt">climate</span> variability and warming trends in MENA and the Red Sea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020090248','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020090248"><span>The Finer Details: <span class="hlt">Climate</span> <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>If you want to know whether you will need sunscreen or an umbrella for tomorrow's picnic, you can simply read the local weather report. However, if you are calculating the impact of gas combustion on global temperatures, or anticipating next year's rainfall levels to set water conservation policy, you must conduct a more comprehensive investigation. Such complex matters require long-range <span class="hlt">modeling</span> techniques that predict broad trends in <span class="hlt">climate</span> development rather than day-to-day details. <span class="hlt">Climate</span> <span class="hlt">models</span> are built from equations that calculate the progression of weather-related conditions over time. Based on the laws of physics, <span class="hlt">climate</span> <span class="hlt">model</span> equations have been developed to predict a number of environmental factors, for example: 1. Amount of solar radiation that hits the Earth. 2. Varying proportions of gases that make up the air. 3. Temperature at the Earth's surface. 4. Circulation of <span class="hlt">ocean</span> and wind currents. 5. Development of cloud cover. Numerical <span class="hlt">modeling</span> of the <span class="hlt">climate</span> can improve our understanding of both the past and, the future. A <span class="hlt">model</span> can confirm the accuracy of environmental measurements taken. in, the past and can even fill in gaps in those records. In addition, by quantifying the relationship between different aspects of <span class="hlt">climate</span>, scientists can estimate how a future change in one aspect may alter the rest of the world. For example, could an increase in the temperature of the Pacific <span class="hlt">Ocean</span> somehow set off a drought on the other side of the world? A computer simulation could lead to an answer for this and other questions. Quantifying the chaotic, nonlinear activities that shape our <span class="hlt">climate</span> is no easy matter. You cannot run these simulations on your desktop computer and expect results by the time you have finished checking your morning e-mail. Efficient and accurate <span class="hlt">climate</span> <span class="hlt">modeling</span> requires powerful computers that can process billions of mathematical calculations in a single second. The NCCS exists to provide this degree of vast computing capability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS23C2025A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS23C2025A"><span>Response of the pelagic system of the Pacific <span class="hlt">Ocean</span> off Baja California Peninsula to the projected effects of <span class="hlt">climate</span> change: insights from a numerical <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arellano, B.; Rivas, D.</p> <p>2015-12-01</p> <p>The response of the physical and biological dynamics of the Pacific <span class="hlt">Ocean</span> off Baja California to the projected effects of <span class="hlt">climate</span> change are studied using numerical simulations. This region is part of the California Current System, which is a highly productive ecosystem due to the seasonal upwelling, supporting all the trophic levels and important fisheries. The response of the ecosystem to the effects of <span class="hlt">climate</span> change is uncertain and the information generated by <span class="hlt">models</span> could be useful to predict future conditions. A three-dimensional hydrodinamical <span class="hlt">model</span> is coupled to a Nitrate-Phytoplankton-Zooplankton-Detritus (NPZD) trophic <span class="hlt">model</span>, and it is forced by the GFDL 3.0 <span class="hlt">model</span> outputs. Monthly climatologies of variables such as temperature, nutrients, wind, and <span class="hlt">ocean</span> circulation patterns during the historical period 1985-2005 are compared to the available observed data in order to assess the <span class="hlt">model</span>'s ability to reproduce the observed patterns. The system's response to a high-emission scenario proposed by the Intergovernmental Panel of <span class="hlt">Climate</span> Change (IPCC) is also studied. The experiments are carried out using data correspondig to the RCP 6.0 scenario during the period 2006-2050.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28465575','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28465575"><span><span class="hlt">Ocean</span> currents modify the coupling between <span class="hlt">climate</span> change and biogeographical shifts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>García Molinos, J; Burrows, M T; Poloczanska, E S</p> <p>2017-05-02</p> <p>Biogeographical shifts are a ubiquitous global response to <span class="hlt">climate</span> change. However, observed shifts across taxa and geographical locations are highly variable and only partially attributable to <span class="hlt">climatic</span> conditions. Such variable outcomes result from the interaction between local <span class="hlt">climatic</span> changes and other abiotic and biotic factors operating across species ranges. Among them, external directional forces such as <span class="hlt">ocean</span> and air currents influence the dispersal of nearly all marine and many terrestrial organisms. Here, using a global meta-dataset of observed range shifts of marine species, we show that incorporating directional agreement between flow and <span class="hlt">climate</span> significantly increases the proportion of explained variance. We propose a simple metric that measures the degrees of directional agreement of <span class="hlt">ocean</span> (or air) currents with thermal gradients and considers the effects of directional forces in predictions of <span class="hlt">climate</span>-driven range shifts. <span class="hlt">Ocean</span> flows are found to both facilitate and hinder shifts depending on their directional agreement with spatial gradients of temperature. Further, effects are shaped by the locations of shifts in the range (trailing, leading or centroid) and taxonomic identity of species. These results support the global effects of <span class="hlt">climatic</span> changes on distribution shifts and stress the importance of framing <span class="hlt">climate</span> expectations in reference to other non-<span class="hlt">climatic</span> interacting factors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5475Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5475Z"><span>Land - <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp</p> <p>2009-04-01</p> <p>, and Interocean Exchanges"; IODP ref. no. 702-full) aims at deciphering the late Neogene <span class="hlt">ocean</span> history of the SW Indian <span class="hlt">Ocean</span>. SAFARI specifically targets the Agulhas Current in the SW Indian <span class="hlt">Ocean</span> that constitutes the strongest western boundary current in the southern hemisphere <span class="hlt">oceans</span>. The Current transports warm and saline surface waters from the tropical Indian <span class="hlt">Ocean</span> to the southern tip of Africa. Exchanges with the atmosphere influence eastern and southern African <span class="hlt">climates</span> including individual weather systems such as extra-tropical cyclone formation in the region and rainfall patterns. <span class="hlt">Ocean</span> <span class="hlt">models</span> further suggest the "leakage" of Agulhas water around South Africa into the Atlantic potentially modulates the Atlantic meridional overturning circulation (MOC) with consequences for <span class="hlt">climate</span> globally. The SAFARI drilling initiative aims to retrieve a suite of long drill cores along the southeast African margin and in the Indian-Atlantic <span class="hlt">ocean</span> gateway. SAFARI will shed light on the history of Agulhas Current warm water transports along the southeast African margin during the late Neogene and its linking with <span class="hlt">ocean-climate</span> developments. Specific objectives of SAFARI are to test (1) the sensitivity of the Agulhas Current to changing <span class="hlt">climates</span> of the Plio/Pleistocene, including upstream forcing linked with equatorial Indian <span class="hlt">Ocean</span> changes and Indonesian Throughflow; (2) the Current's influence on eastern and southern Africa <span class="hlt">climates</span>, including rain fall patterns and vegetation changes; (3) buoyancy transfer to the Atlantic by Agulhas leakage around southern Africa, and (4) the contribution of variable Agulhas Leakage to shifts of the Atlantic MOC during episodes of major <span class="hlt">ocean</span> and <span class="hlt">climate</span> reorganizations of the past 5 Ma. These studies will provide insight into the Current's influence on eastern and southern African terrestrial <span class="hlt">climates</span>, including its possible impact on the late Neogene evolution of large mammals including hominids. The ICDP and IODP drilling campaigns will</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GMD.....9.3231G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GMD.....9.3231G"><span>OMIP contribution to CMIP6: experimental and diagnostic protocol for the physical component of the <span class="hlt">Ocean</span> <span class="hlt">Model</span> Intercomparison Project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Griffies, Stephen M.; Danabasoglu, Gokhan; Durack, Paul J.; Adcroft, Alistair J.; Balaji, V.; Böning, Claus W.; Chassignet, Eric P.; Curchitser, Enrique; Deshayes, Julie; Drange, Helge; Fox-Kemper, Baylor; Gleckler, Peter J.; Gregory, Jonathan M.; Haak, Helmuth; Hallberg, Robert W.; Heimbach, Patrick; Hewitt, Helene T.; Holland, David M.; Ilyina, Tatiana; Jungclaus, Johann H.; Komuro, Yoshiki; Krasting, John P.; Large, William G.; Marsland, Simon J.; Masina, Simona; McDougall, Trevor J.; Nurser, A. J. George; Orr, James C.; Pirani, Anna; Qiao, Fangli; Stouffer, Ronald J.; Taylor, Karl E.; Treguier, Anne Marie; Tsujino, Hiroyuki; Uotila, Petteri; Valdivieso, Maria; Wang, Qiang; Winton, Michael; Yeager, Stephen G.</p> <p>2016-09-01</p> <p>The <span class="hlt">Ocean</span> <span class="hlt">Model</span> Intercomparison Project (OMIP) is an endorsed project in the Coupled <span class="hlt">Model</span> Intercomparison Project Phase 6 (CMIP6). OMIP addresses CMIP6 science questions, investigating the origins and consequences of systematic <span class="hlt">model</span> biases. It does so by providing a framework for evaluating (including assessment of systematic biases), understanding, and improving <span class="hlt">ocean</span>, sea-ice, tracer, and biogeochemical components of <span class="hlt">climate</span> and earth system <span class="hlt">models</span> contributing to CMIP6. Among the WCRP Grand Challenges in <span class="hlt">climate</span> science (GCs), OMIP primarily contributes to the regional sea level change and near-term (<span class="hlt">climate</span>/decadal) prediction GCs.OMIP provides (a) an experimental protocol for global <span class="hlt">ocean</span>/sea-ice <span class="hlt">models</span> run with a prescribed atmospheric forcing; and (b) a protocol for <span class="hlt">ocean</span> diagnostics to be saved as part of CMIP6. We focus here on the physical component of OMIP, with a companion paper (Orr et al., 2016) detailing methods for the inert chemistry and interactive biogeochemistry. The physical portion of the OMIP experimental protocol follows the interannual Coordinated <span class="hlt">Ocean</span>-ice Reference Experiments (CORE-II). Since 2009, CORE-I (Normal Year Forcing) and CORE-II (Interannual Forcing) have become the standard methods to evaluate global <span class="hlt">ocean</span>/sea-ice simulations and to examine mechanisms for forced <span class="hlt">ocean</span> <span class="hlt">climate</span> variability. The OMIP diagnostic protocol is relevant for any <span class="hlt">ocean</span> <span class="hlt">model</span> component of CMIP6, including the DECK (Diagnostic, Evaluation and Characterization of Klima experiments), historical simulations, FAFMIP (Flux Anomaly Forced MIP), C4MIP (Coupled Carbon Cycle <span class="hlt">Climate</span> MIP), DAMIP (Detection and Attribution MIP), DCPP (Decadal <span class="hlt">Climate</span> Prediction Project), ScenarioMIP, HighResMIP (High Resolution MIP), as well as the <span class="hlt">ocean</span>/sea-ice OMIP simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.U33B..07V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.U33B..07V"><span><span class="hlt">Climate</span> <span class="hlt">Model</span> Tests of the Early Anthropogenic Hypothesis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vavrus, S.; Kutzbach, J.; Philippon, G.</p> <p>2008-12-01</p> <p>We test the hypothesis that greenhouse gas emissions produced by the combination of early and recent human activities, augmented by additional rises in greenhouse gases through <span class="hlt">ocean</span> feedbacks, have kept the <span class="hlt">climate</span> warmer than its natural level and offset an incipient glaciation. We use four different configurations of NCAR's Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> to investigate the natural <span class="hlt">climate</span> that should exist today if CO2 and CH4 concentrations had fallen to their average levels reached during previous interglaciations. The <span class="hlt">model</span> simulations consist of three using a coupled atmosphere-slab <span class="hlt">ocean</span> configuration---fixed land cover at moderate (T42) and high (T85) <span class="hlt">model</span> resolution and interactive vegetation composition at T42 resolution--and one employing a coupled atmosphere-dynamical <span class="hlt">ocean</span> configuration and fixed land cover at T42 resolution. With greenhouse gas concentrations lowered to their estimated natural levels, global mean temperature falls by 2.5-3.0 K in all four experiments. Of the total global cooling with fixed land cover and moderate <span class="hlt">model</span> resolution, 38% (62%) is attributable to early agricultural activities (industrialization), while early agriculture accounts for approximately half of the expanded permanent snow cover area. The greenhouse cooling triggers widespread glacial inception in the Northern Hemisphere, where permanent snow cover expands by at least 80% and even more with the addition of enhanced <span class="hlt">model</span> processes: 130% with the dynamical <span class="hlt">ocean</span>, 150% with high (T85) <span class="hlt">model</span> resolution, and 200% with vegetation feedbacks included. The regional pattern of incipient glaciation is strongly influenced by atmospheric and circulation changes, sea ice feedbacks, and <span class="hlt">model</span> resolution. The simulation with a dynamical <span class="hlt">ocean</span> produces a decrease in vertically integrated global <span class="hlt">ocean</span> temperature of 1.25 K, a 20% weakening of the Atlantic meridional overturning cell, and an expansion of sea ice and reduced upwelling in the Southern <span class="hlt">Ocean</span>. Viewed from the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23063067','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23063067"><span><span class="hlt">Climate</span> change and <span class="hlt">ocean</span> acidification-interactions with aquatic toxicology.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nikinmaa, Mikko</p> <p>2013-01-15</p> <p>The possibilities for interactions between toxicants and <span class="hlt">ocean</span> acidification are reviewed from two angles. First, it is considered how toxicant responses may affect <span class="hlt">ocean</span> acidification by influencing the carbon dioxide balance. Second, it is introduced, how the possible changes in environmental conditions (temperature, pH and oxygenation), expected to be associated with <span class="hlt">climate</span> change and <span class="hlt">ocean</span> acidification, may interact with the toxicant responses of organisms, especially fish. One significant weakness in available data is that toxicological research has seldom been connected with ecological and physiological/biochemical research evaluating the responses of organisms to temperature, pH or oxygenation changes occurring in the natural environment. As a result, although there are significant potential interactions between toxicants and natural environmental responses pertaining to <span class="hlt">climate</span> change and <span class="hlt">ocean</span> acidification, it is very poorly known if such interactions actually occur, and can be behind the observed disturbances in the function and distribution of organisms in our seas. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996PalOc..11..579S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996PalOc..11..579S"><span>Can increased poleward <span class="hlt">oceanic</span> heat flux explain the warm Cretaceous <span class="hlt">climate</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Gavin A.; Mysak, Lawrence A.</p> <p>1996-10-01</p> <p>The poleward transport of heat in the mid-Cretaceous (100 Ma) is examined using an idealized coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">model</span>. The <span class="hlt">oceanic</span> component consists of two zonally averaged basins representing the proto-Pacific and proto-Indian <span class="hlt">oceans</span> and <span class="hlt">models</span> the dynamics of the meridional thermohaline circulation. The atmospheric component is a simple energy and moisture balance <span class="hlt">model</span> which includes the diffusive meridional transport of sensible heat and moisture. The <span class="hlt">ocean</span> <span class="hlt">model</span> is spun up with a variety of plausible Cretaceous surface temperature and salinity profiles, and a consistent atmosphere is objectively derived based on the resultant sea surface temperature and the surface heat and freshwater fluxes. The coupled <span class="hlt">model</span> does not exhibit <span class="hlt">climate</span> drift. Multiple equilibria of the coupled <span class="hlt">model</span> are found that break the initial symmetry of the <span class="hlt">ocean</span> circulation; several of these equilibria have one-cell (northern or southern sinking) thermohaline circulation patterns. Two main classes of circulation are found: circulations where the densest water is relatively cool and is formed at the polar latitudes and circulations where the densest water is warm, but quite saline, and the strongest sinking occurs at the tropics. In all cases, significant amounts of warm, saline bottom water are formed in the proto-Indian basin which modify the deepwater characteristics in the larger (proto-Pacific) basin. Temperatures in the deep <span class="hlt">ocean</span> are warm, 10°-17°C, in agreement with benthic foraminiferal oxygen isotope data. The poleward transport of heat in the <span class="hlt">modeled</span> Cretaceous <span class="hlt">oceans</span> is larger than in some comparable <span class="hlt">models</span> of the present day thermohaline circulation and significantly larger than estimates of similar processes in the present-day <span class="hlt">ocean</span>. It is consistently larger in the polar sinking cases when compared with that seen in the tropical sinking cases, but this represents an increase of only 10%. The largest increase over present-day <span class="hlt">model</span> transports is in the atmospheric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037880','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037880"><span>GFDL's ESM2 global coupled <span class="hlt">climate</span>-carbon Earth System <span class="hlt">Models</span>. Part I: physical formulation and baseline simulation characteristics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dunne, John P.; John, Jasmin G.; Adcroft, Alistair J.; Griffies, Stephen M.; Hallberg, Robert W.; Shevalikova, Elena; Stouffer, Ronald J.; Cooke, William; Dunne, Krista A.; Harrison, Matthew J.; Krasting, John P.; Malyshev, Sergey L.; Milly, P.C.D.; Phillipps, Peter J.; Sentman, Lori A.; Samuels, Bonita L.; Spelman, Michael J.; Winton, Michael; Wittenberg, Andrew T.; Zadeh, Niki</p> <p>2012-01-01</p> <p>We describe the physical <span class="hlt">climate</span> formulation and simulation characteristics of two new global coupled carbon-<span class="hlt">climate</span> Earth System <span class="hlt">Models</span>, ESM2M and ESM2G. These <span class="hlt">models</span> demonstrate similar <span class="hlt">climate</span> fidelity as the Geophysical Fluid Dynamics Laboratory's previous CM2.1 <span class="hlt">climate</span> <span class="hlt">model</span> while incorporating explicit and consistent carbon dynamics. The two <span class="hlt">models</span> differ exclusively in the physical <span class="hlt">ocean</span> component; ESM2M uses Modular <span class="hlt">Ocean</span> <span class="hlt">Model</span> version 4.1 with vertical pressure layers while ESM2G uses Generalized <span class="hlt">Ocean</span> Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the <span class="hlt">ocean</span> mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of <span class="hlt">ocean</span> dynamics on <span class="hlt">climate</span> variability is highlighted in the El Niño-Southern Oscillation being overly strong in ESM2M and overly weak ESM2G relative to observations. Thus, while ESM2G might better represent <span class="hlt">climate</span> changes relating to: total heat content variability given its lack of long term drift, gyre circulation and ventilation in the North Pacific, tropical Atlantic and Indian <span class="hlt">Oceans</span>, and depth structure in the overturning and abyssal flows, ESM2M might better represent <span class="hlt">climate</span> changes relating to: surface circulation given its superior surface temperature, salinity and height patterns, tropical Pacific circulation and variability, and Southern <span class="hlt">Ocean</span> dynamics. Our overall assessment is that neither <span class="hlt">model</span> is fundamentally superior to the other, and that both <span class="hlt">models</span> achieve sufficient fidelity to allow meaningful <span class="hlt">climate</span> and earth system <span class="hlt">modeling</span> applications. This affords us the ability to assess the role of <span class="hlt">ocean</span> configuration on earth system interactions in the context of two state-of-the-art coupled carbon-<span class="hlt">climate</span> <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940038873&hterms=atmospheric+rivers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Datmospheric%2Brivers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940038873&hterms=atmospheric+rivers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Datmospheric%2Brivers"><span>Continental-scale river flow in <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, James R.; Russell, Gary L.; Caliri, Guilherme</p> <p>1994-01-01</p> <p>The hydrologic cycle is a major part of the global <span class="hlt">climate</span> system. There is an atmospheric flux of water from the <span class="hlt">ocean</span> surface to the continents. The cycle is closed by return flow in rivers. In this paper a river routing <span class="hlt">model</span> is developed to use with grid box <span class="hlt">climate</span> <span class="hlt">models</span> for the whole earth. The routing <span class="hlt">model</span> needs an algorithm for the river mass flow and a river direction file, which has been compiled for 4 deg x 5 deg and 2 deg x 2.5 deg resolutions. River basins are defined by the direction files. The river flow leaving each grid box depends on river and lake mass, downstream distance, and an effective flow speed that depends on topography. As input the routing <span class="hlt">model</span> uses monthly land source runoff from a 5-yr simulation of the NASA/GISS atmospheric <span class="hlt">climate</span> <span class="hlt">model</span> (Hansen et al.). The land source runoff from the 4 deg x 5 deg resolution <span class="hlt">model</span> is quartered onto a 2 deg x 2.5 deg grid, and the effect of grid resolution is examined. Monthly flow at the mouth of the world's major rivers is compared with observations, and a global error function for river flow is used to evaluate the routing <span class="hlt">model</span> and its sensitivity to physical parameters. Three basinwide parameters are introduced: the river length weighted by source runoff, the turnover rate, and the basinwide speed. Although the values of these parameters depend on the resolution at which the rivers are defined, the values should converge as the grid resolution becomes finer. When the routing scheme described here is coupled with a <span class="hlt">climate</span> <span class="hlt">model</span>'s source runoff, it provides the basis for closing the hydrologic cycle in coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">models</span> by realistically allowing water to return to the <span class="hlt">ocean</span> at the correct location and with the proper magnitude and timing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPC53A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPC53A..07L"><span>Atlantic Induced Pan-tropical <span class="hlt">Climate</span> Variability in the Upper-<span class="hlt">ocean</span> and Atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.</p> <p>2016-02-01</p> <p>During the last three decades, tropical sea surface temperature (SST) exhibited dipole-like trends, with warming over the tropical Atlantic and Indo-Western Pacific but cooling over the Eastern Pacific. The Eastern Pacific cooling has recently been identified as a driver of the global warming hiatus. Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian <span class="hlt">Ocean</span>, which could potentially contribute to this zonally asymmetric SST pattern. However, the mechanisms and the interactions between these teleconnections remain unclear. To investigate these questions, we performed a `pacemaker' simulation by restoring the tropical Atlantic SST changes in a state-of-the-art <span class="hlt">climate</span> <span class="hlt">model</span> - the CESM1. Results show that the Atlantic plays a key role in initiating the tropical-wide teleconnections, and the Atlantic-induced anomalies contribute 55%-75% of the total tropical SST and circulation changes during the satellite era. A hierarchy of <span class="hlt">oceanic</span> and atmospheric <span class="hlt">models</span> are then used to investigate the physical mechanisms of these teleconnections: the Atlantic warming enhances atmospheric deep convection, drives easterly wind anomalies over the Indo-Western Pacific through the Kelvin wave, and westerly anomalies over the eastern Pacific as Rossby waves, in line with Gill's solution (Fig1a). These wind changes induce an Indo-Western Pacific warming via the wind-evaporation-SST effect, and this warming intensifies the La Niña-type response in the upper Pacific <span class="hlt">Ocean</span> by enhancing the easterly trade winds and through the Bjerknes <span class="hlt">ocean</span>-dynamical processes (Fig1b). The teleconnection finally develops into a tropical-wide SST dipole pattern with an enhanced trade wind and Walker circulation, similar as the observed changes during the satellite era. This mechanism reveals that the tropical <span class="hlt">ocean</span> basins are more tightly connected than previously thought, and the Atlantic plays a key role in the tropical <span class="hlt">climate</span> pattern formation and further the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdSR...13...75G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSR...13...75G"><span>Twenty-first century wave <span class="hlt">climate</span> projections for Ireland and surface winds in the North Atlantic <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallagher, Sarah; Gleeson, Emily; Tiron, Roxana; McGrath, Ray; Dias, Frédéric</p> <p>2016-04-01</p> <p>Ireland has a highly energetic wave and wind <span class="hlt">climate</span>, and is therefore uniquely placed in terms of its <span class="hlt">ocean</span> renewable energy resource. The socio-economic importance of the marine resource to Ireland makes it critical to quantify how the wave and wind <span class="hlt">climate</span> may change in the future due to global <span class="hlt">climate</span> change. Projected changes in winds, <span class="hlt">ocean</span> waves and the frequency and severity of extreme weather events should be carefully assessed for long-term marine and coastal planning. We derived an ensemble of future wave <span class="hlt">climate</span> projections for Ireland using the EC-Earth global <span class="hlt">climate</span> <span class="hlt">model</span> and the WAVEWATCH III® wave <span class="hlt">model</span>, by comparing the future 30-year period 2070-2099 to the period 1980-2009 for the RCP4.5 and the RCP8.5 forcing scenarios. This dataset is currently the highest resolution wave projection dataset available for Ireland. The EC-Earth ensemble predicts decreases in mean (up to 2 % for RCP4.5 and up to 3.5 % for RCP8.5) 10 m wind speeds over the North Atlantic <span class="hlt">Ocean</span> (5-75° N, 0-80° W) by the end of the century, which will consequently affect swell generation for the Irish wave <span class="hlt">climate</span>. The WAVEWATCH III® <span class="hlt">model</span> predicts an overall decrease in annual and seasonal mean significant wave heights around Ireland, with the largest decreases in summer (up to 15 %) and winter (up to 10 %) for RCP8.5. Projected decreases in mean significant wave heights for spring and autumn were found to be small for both forcing scenarios (less than 5 %), with no significant decrease found for RCP4.5 off the west coast in those seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhRvE..70c7301F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhRvE..70c7301F"><span>1/f <span class="hlt">model</span> for long-time memory of the <span class="hlt">ocean</span> surface temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fraedrich, Klaus; Luksch, Ute; Blender, Richard</p> <p>2004-09-01</p> <p>The 1/f spectrum of the <span class="hlt">ocean</span> surface temperature in the Atlantic and Pacific midlatitudes is explained by a simple vertical diffusion <span class="hlt">model</span> with a shallow mixed layer on top of a deep <span class="hlt">ocean</span>. The <span class="hlt">model</span> is forced at the air-sea interface with the total surface heat flux from a 1000 year <span class="hlt">climate</span> simulation. The analysis reveals the role of <span class="hlt">ocean</span> advection and substantiates estimates of internal thermal diffusivities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1406778-pyhector-python-interface-simple-climate-model-hector','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1406778-pyhector-python-interface-simple-climate-model-hector"><span>pyhector: A Python interface for the simple <span class="hlt">climate</span> <span class="hlt">model</span> Hector</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Willner, Sven N.; Hartin, Corinne; Gieseke, Robert</p> <p>2017-04-01</p> <p>Here, pyhector is a Python interface for the simple <span class="hlt">climate</span> <span class="hlt">model</span> Hector (Hartin et al. 2015) developed in C++. Simple <span class="hlt">climate</span> <span class="hlt">models</span> like Hector can, for instance, be used in the analysis of scenarios within integrated assessment <span class="hlt">models</span> like GCAM1, in the emulation of complex <span class="hlt">climate</span> <span class="hlt">models</span>, and in uncertainty analyses. Hector is an open-source, object oriented, simple global <span class="hlt">climate</span> carbon cycle <span class="hlt">model</span>. Its carbon cycle consists of a one pool atmosphere, three terrestrial pools which can be broken down into finer biomes or regions, and four carbon pools in the <span class="hlt">ocean</span> component. The terrestrial carbon cycle includes primary productionmore » and respiration fluxes. The <span class="hlt">ocean</span> carbon cycle circulates carbon via a simplified thermohaline circulation, calculating air-sea fluxes as well as the marine carbonate system. The <span class="hlt">model</span> input is time series of greenhouse gas emissions; as example scenarios for these the Pyhector package contains the Representative Concentration Pathways (RCPs)2.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24752011','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24752011"><span>Projected range contractions of European protected <span class="hlt">oceanic</span> montane plant communities: focus on <span class="hlt">climate</span> change impacts is essential for their future conservation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hodd, Rory L; Bourke, David; Skeffington, Micheline Sheehy</p> <p>2014-01-01</p> <p>Global <span class="hlt">climate</span> is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with <span class="hlt">oceanic</span> montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the north-west hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of <span class="hlt">climate</span> change on the distribution of these species and assesses the implications for EU Habitats Directive-protected <span class="hlt">oceanic</span> montane plant communities. We applied an ensemble of species distribution <span class="hlt">modelling</span> techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future <span class="hlt">climate</span> change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable <span class="hlt">climate</span> space, primarily at lower altitudes, or that areas of suitable <span class="hlt">climate</span> will principally shift northwards. In particular, rare <span class="hlt">oceanic</span> montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current <span class="hlt">climate</span> space. Significantly different projected range change responses were found between 1) <span class="hlt">oceanic</span> montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to <span class="hlt">climate</span>, significantly improved the statistical and spatial performance of <span class="hlt">models</span>. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving <span class="hlt">oceanic</span> montane plant communities. Conservation management plans need significantly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3994024','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3994024"><span>Projected Range Contractions of European Protected <span class="hlt">Oceanic</span> Montane Plant Communities: Focus on <span class="hlt">Climate</span> Change Impacts Is Essential for Their Future Conservation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Skeffington, Micheline Sheehy</p> <p>2014-01-01</p> <p>Global <span class="hlt">climate</span> is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with <span class="hlt">oceanic</span> montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the north-west hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of <span class="hlt">climate</span> change on the distribution of these species and assesses the implications for EU Habitats Directive-protected <span class="hlt">oceanic</span> montane plant communities. We applied an ensemble of species distribution <span class="hlt">modelling</span> techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future <span class="hlt">climate</span> change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable <span class="hlt">climate</span> space, primarily at lower altitudes, or that areas of suitable <span class="hlt">climate</span> will principally shift northwards. In particular, rare <span class="hlt">oceanic</span> montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current <span class="hlt">climate</span> space. Significantly different projected range change responses were found between 1) <span class="hlt">oceanic</span> montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to <span class="hlt">climate</span>, significantly improved the statistical and spatial performance of <span class="hlt">models</span>. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving <span class="hlt">oceanic</span> montane plant communities. Conservation management plans need significantly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Sci...350..778A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Sci...350..778A"><span><span class="hlt">Climate</span> change in the <span class="hlt">oceans</span>: Human impacts and responses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allison, Edward H.; Bassett, Hannah R.</p> <p>2015-11-01</p> <p>Although it has far-reaching consequences for humanity, attention to <span class="hlt">climate</span> change impacts on the <span class="hlt">ocean</span> lags behind concern for impacts on the atmosphere and land. Understanding these impacts, as well as society’s diverse perspectives and multiscale responses to the changing <span class="hlt">oceans</span>, requires a correspondingly diverse body of scholarship in the physical, biological, and social sciences and humanities. This can ensure that a plurality of values and viewpoints is reflected in the research that informs <span class="hlt">climate</span> policy and may enable the concerns of maritime societies and economic sectors to be heard in key adaptation and mitigation discussions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170002562','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170002562"><span>Impacts of Interactive Stratospheric Chemistry on Antarctic and Southern <span class="hlt">Ocean</span> <span class="hlt">Climate</span> Change in the Goddard Earth Observing System Version 5 (GEOS-5)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Feng; Vikhliaev, Yury V.; Newman, Paul A.; Pawson, Steven; Perlwitz, Judith; Waugh, Darryn W.; Douglass, Anne R.</p> <p>2016-01-01</p> <p>Stratospheric ozone depletion plays a major role in driving <span class="hlt">climate</span> change in the Southern Hemisphere. To date, many <span class="hlt">climate</span> <span class="hlt">models</span> prescribe the stratospheric ozone layer's evolution using monthly and zonally averaged ozone fields. However, the prescribed ozone underestimates Antarctic ozone depletion and lacks zonal asymmetries. In this study we investigate the impact of using interactive stratospheric chemistry instead of prescribed ozone on <span class="hlt">climate</span> change simulations of the Antarctic and Southern <span class="hlt">Ocean</span>. Two sets of 1960-2010 ensemble transient simulations are conducted with the coupled <span class="hlt">ocean</span> version of the Goddard Earth Observing System <span class="hlt">Model</span>, version 5: one with interactive stratospheric chemistry and the other with prescribed ozone derived from the same interactive simulations. The <span class="hlt">model</span>'s climatology is evaluated using observations and reanalysis. Comparison of the 1979-2010 <span class="hlt">climate</span> trends between these two simulations reveals that interactive chemistry has important effects on <span class="hlt">climate</span> change not only in the Antarctic stratosphere, troposphere, and surface, but also in the Southern <span class="hlt">Ocean</span> and Antarctic sea ice. Interactive chemistry causes stronger Antarctic lower stratosphere cooling and circumpolar westerly acceleration during November-December-January. It enhances stratosphere-troposphere coupling and leads to significantly larger tropospheric and surface westerly changes. The significantly stronger surface wind stress trends cause larger increases of the Southern <span class="hlt">Ocean</span> Meridional Overturning Circulation, leading to year-round stronger <span class="hlt">ocean</span> warming near the surface and enhanced Antarctic sea ice decrease.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5017J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5017J"><span>Kawase & McDermott revisited with a proper <span class="hlt">ocean</span> <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jochum, Markus; Poulsen, Mads; Nuterman, Roman</p> <p>2017-04-01</p> <p>A suite of experiments with global <span class="hlt">ocean</span> <span class="hlt">models</span> is used to test the hypothesis that Southern <span class="hlt">Ocean</span> (SO) winds can modify the strength of the Atlantic Meridional Overturning Circulation (AMOC). It is found that for 3 and 1 degree resolution <span class="hlt">models</span> the results are consistent with Toggweiler & Samuels (1995): stronger SO winds lead to a slight increase of the AMOC. In the simulations with 1/10 degree resolution, however, stronger SO winds weaken the AMOC. We show that these different outcomes are determined by the <span class="hlt">models</span>' representation of topographic Rossby and Kelvin waves. Consistent with previous literature based on theory and idealized <span class="hlt">models</span>, first baroclinic waves are slower in the coarse resolution <span class="hlt">models</span>, but still manage to establish a pattern of global response that is similar to the one in the eddy-permitting <span class="hlt">model</span>. Because of its different stratification, however, the Atlantic signal is transmitted by higher baroclinic modes. In the coarse resolution <span class="hlt">model</span> these higher modes are dissipated before they reach 30N, whereas in the eddy-permitting <span class="hlt">model</span> they reach the subpolar gyre undiminished. This inability of non-eddy-permitting <span class="hlt">ocean</span> <span class="hlt">models</span> to represent planetary waves with higher baroclinic modes casts doubt on the ability of <span class="hlt">climate</span> <span class="hlt">models</span> to represent non-local effects of <span class="hlt">climate</span> change. Ideas on how to overcome these difficulties will be discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29374176','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29374176"><span>Decadal <span class="hlt">climate</span> predictability in the southern Indian <span class="hlt">Ocean</span> captured by SINTEX-F using a simple SST-nudging scheme.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morioka, Yushi; Doi, Takeshi; Behera, Swadhin K</p> <p>2018-01-26</p> <p>Decadal <span class="hlt">climate</span> variability in the southern Indian <span class="hlt">Ocean</span> has great influences on southern African <span class="hlt">climate</span> through modulation of atmospheric circulation. Although many efforts have been made to understanding physical mechanisms, predictability of the decadal <span class="hlt">climate</span> variability, in particular, the internally generated variability independent from external atmospheric forcing, remains poorly understood. This study investigates predictability of the decadal <span class="hlt">climate</span> variability in the southern Indian <span class="hlt">Ocean</span> using a coupled general circulation <span class="hlt">model</span>, called SINTEX-F. The ensemble members of the decadal reforecast experiments were initialized with a simple sea surface temperature (SST) nudging scheme. The observed positive and negative peaks during late 1990s and late 2000s are well reproduced in the reforecast experiments initiated from 1994 and 1999, respectively. The experiments initiated from 1994 successfully capture warm SST and high sea level pressure anomalies propagating from the South Atlantic to the southern Indian <span class="hlt">Ocean</span>. Also, the other experiments initiated from 1999 skillfully predict phase change from a positive to negative peak. These results suggest that the SST-nudging initialization has the essence to capture the predictability of the internally generated decadal <span class="hlt">climate</span> variability in the southern Indian <span class="hlt">Ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15794819','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15794819"><span><span class="hlt">Ocean</span> <span class="hlt">climate</span> and seal condition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Le Boeuf, Burney J; Crocker, Daniel E</p> <p>2005-03-28</p> <p>The condition of many marine mammals varies with fluctuations in productivity and food supply in the <span class="hlt">ocean</span> basin where they forage. Prey is impacted by physical environmental variables such as cyclic warming trends. The weaning weight of northern elephant seal pups, Mirounga angustirostris, being closely linked to maternal condition, indirectly reflects prey availability and foraging success of pregnant females in deep waters of the northeastern Pacific. The aim of this study was to examine the effect of <span class="hlt">ocean</span> <span class="hlt">climate</span> on foraging success in this deep-diving marine mammal over the course of three decades, using cohort weaning weight as the principal metric of successful resource accrual. The mean annual weaning weight of pups declined from 1975 to the late 1990s, a period characterized by a large-scale, basin-wide warm decadal regime that included multiple strong or long-duration El Niños; and increased with a return to a cool decadal regime from about 1999 to 2004. Increased foraging effort and decreased mass gain of adult females, indicative of reduced foraging success and nutritional stress, were associated with high <span class="hlt">ocean</span> temperatures. Despite ranging widely and foraging deeply in cold waters beyond coastal thermoclines in the northeastern Pacific, elephant seals are impacted significantly by <span class="hlt">ocean</span> thermal dynamics. <span class="hlt">Ocean</span> warming redistributes prey decreasing foraging success of females, which in turn leads to lower weaning mass of pups. Annual fluctuations in weaning mass, in turn, reflect the foraging success of females during the year prior to giving birth and signals changes in <span class="hlt">ocean</span> temperature cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NHESD...2.2117A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NHESD...2.2117A"><span>Medicanes in an <span class="hlt">ocean</span>-atmosphere coupled regional <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akhtar, N.; Brauch, J.; Dobler, A.; Béranger, K.; Ahrens, B.</p> <p>2014-03-01</p> <p>So-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and warm-core Mediterranean cyclones that exhibit some similarities to tropical cyclones. The strong cyclonic winds associated with medicanes threaten the highly populated coastal areas around the Mediterranean basin. To reduce the risk of casualties and overall negative impacts, it is important to improve the understanding of medicanes with the use of numerical <span class="hlt">models</span>. In this study, we employ an atmospheric limited-area <span class="hlt">model</span> (COSMO-CLM) coupled with a one-dimensional <span class="hlt">ocean</span> <span class="hlt">model</span> (1-D NEMO-MED12) to simulate medicanes. The aim of this study is to assess the robustness of the coupled <span class="hlt">model</span> in simulating these extreme events. For this purpose, 11 historical medicane events are simulated using the atmosphere-only <span class="hlt">model</span>, COSMO-CLM, and coupled <span class="hlt">model</span>, with different setups (horizontal atmospheric grid-spacings of 0.44°, 0.22°, and 0.08°; with/without spectral nudging, and an <span class="hlt">ocean</span> grid-spacing of 1/12°). The results show that at high-resolution, the coupled <span class="hlt">model</span> is able to not only simulate most of medicane events but also improve the track length, core temperature, and wind speed of simulated medicanes compared to the atmosphere-only simulations. The results suggest that the coupled <span class="hlt">model</span> is more proficient for systemic and detailed studies of historical medicane events, and that this <span class="hlt">model</span> can be an effective tool for future projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NHESS..14.2189A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NHESS..14.2189A"><span>Medicanes in an <span class="hlt">ocean</span>-atmosphere coupled regional <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akhtar, N.; Brauch, J.; Dobler, A.; Béranger, K.; Ahrens, B.</p> <p>2014-08-01</p> <p>So-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and warm-core Mediterranean cyclones that exhibit some similarities to tropical cyclones. The strong cyclonic winds associated with medicanes threaten the highly populated coastal areas around the Mediterranean basin. To reduce the risk of casualties and overall negative impacts, it is important to improve the understanding of medicanes with the use of numerical <span class="hlt">models</span>. In this study, we employ an atmospheric limited-area <span class="hlt">model</span> (COSMO-CLM) coupled with a one-dimensional <span class="hlt">ocean</span> <span class="hlt">model</span> (1-D NEMO-MED12) to simulate medicanes. The aim of this study is to assess the robustness of the coupled <span class="hlt">model</span> in simulating these extreme events. For this purpose, 11 historical medicane events are simulated using the atmosphere-only <span class="hlt">model</span>, COSMO-CLM, and coupled <span class="hlt">model</span>, with different setups (horizontal atmospheric grid spacings of 0.44, 0.22, and 0.08°; with/without spectral nudging, and an <span class="hlt">ocean</span> grid spacing of 1/12°). The results show that at high resolution, the coupled <span class="hlt">model</span> is able to not only simulate most of medicane events but also improve the track length, core temperature, and wind speed of simulated medicanes compared to the atmosphere-only simulations. The results suggest that the coupled <span class="hlt">model</span> is more proficient for systemic and detailed studies of historical medicane events, and that this <span class="hlt">model</span> can be an effective tool for future projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C12A..06A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C12A..06A"><span><span class="hlt">Modeling</span> dynamics of large tabular icebergs submerged in the <span class="hlt">ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adcroft, A.; Stern, A. A.; Sergienko, O. V.</p> <p>2017-12-01</p> <p>Large tabular icebergs account for a major fraction of the ice calved from the Antarctic ice shelves, and have long lifetimes due to their size. They drift for long distances, interacting with the local <span class="hlt">ocean</span> circulation, impacting bottom-water formation, sea-ice formation, and biological productivity in the vicinity of the icebergs. However, due to their large horizontal extent and mass, it is challenging to consistently represent large tabular icebergs in global <span class="hlt">ocean</span> circulation <span class="hlt">models</span> and so large tabular icebergs are not currently represented in <span class="hlt">climate</span> <span class="hlt">models</span>. In this study we develop a novel framework to <span class="hlt">model</span> large tabular icebergs submerged in the <span class="hlt">ocean</span>. In this framework, a tabular iceberg is represented by a collection of Lagrangian elements that are linked through rigid bonds. The Lagrangian elements are finite-area modifications of the point-particles used in previous studies to represent small icebergs. These elements interact with the <span class="hlt">ocean</span> by exerting pressure on the <span class="hlt">ocean</span> surface, and through melt water and momentum exchange. A breaking of the rigid bonds allows the <span class="hlt">model</span> to emulate calving events (i.e. detachment of a tabular iceberg from an ice shelf), and to emulate the breaking up of tabular icebergs into smaller pieces. Idealized simulations of the calving of a tabular iceberg, subsequent drift and breakup, demonstrate the capabilities of the new framework with a promise that <span class="hlt">climate</span> <span class="hlt">models</span> may soon be able to represent large tabular icebergs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15264594','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15264594"><span>The Swedish Regional <span class="hlt">Climate</span> <span class="hlt">Modelling</span> Programme, SWECLIM: a review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rummukainen, Markku; Bergström, Sten; Persson, Gunn; Rodhe, Johan; Tjernström, Michael</p> <p>2004-06-01</p> <p>The Swedish Regional <span class="hlt">Climate</span> <span class="hlt">Modelling</span> Programme, SWECLIM, was a 6.5-year national research network for regional <span class="hlt">climate</span> <span class="hlt">modeling</span>, regional <span class="hlt">climate</span> change projections and hydrological impact assessment and information to a wide range of stakeholders. Most of the program activities focussed on the regional <span class="hlt">climate</span> system of Northern Europe. This led to the establishment of an advanced, coupled atmosphere-<span class="hlt">ocean</span>-hydrology regional <span class="hlt">climate</span> <span class="hlt">model</span> system, a suite of regional <span class="hlt">climate</span> change projections and progress on relevant data and process studies. These were, in turn, used for information and educational purposes, as a starting point for impact analyses on different societal sectors and provided contributions also to international <span class="hlt">climate</span> research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1613216B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1613216B"><span>In-situ databases and comparison of ESA <span class="hlt">Ocean</span> Colour <span class="hlt">Climate</span> Change Initiative (OC-CCI) products with precursor data, towards an integrated approach for <span class="hlt">ocean</span> colour validation and <span class="hlt">climate</span> studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brotas, Vanda; Valente, André; Couto, André B.; Grant, Mike; Chuprin, Andrei; Jackson, Thomas; Groom, Steve; Sathyendranath, Shubha</p> <p>2014-05-01</p> <p><span class="hlt">Ocean</span> colour (OC) is an <span class="hlt">Oceanic</span> Essential <span class="hlt">Climate</span> Variable, which is used by <span class="hlt">climate</span> <span class="hlt">modellers</span> and researchers. The European Space Agency (ESA) <span class="hlt">Climate</span> Change Initiative project, is the ESA response for the need of <span class="hlt">climate</span>-quality satellite data, with the goal of providing stable, long-term, satellite-based ECV data products. The ESA <span class="hlt">Ocean</span> Colour CCI focuses on the production of <span class="hlt">Ocean</span> Colour ECV uses remote sensing reflectances to derive inherent optical properties and chlorophyll a concentration from ESA's MERIS (2002-2012) and NASA's SeaWiFS (1997 - 2010) and MODIS (2002-2012) sensor archives. This work presents an integrated approach by setting up a global database of in situ measurements and by inter-comparing OC-CCI products with pre-cursor datasets. The availability of in situ databases is fundamental for the validation of satellite derived <span class="hlt">ocean</span> colour products. A global distribution in situ database was assembled, from several pre-existing datasets, with data spanning between 1997 and 2012. It includes in-situ measurements of remote sensing reflectances, concentration of chlorophyll-a, inherent optical properties and diffuse attenuation coefficient. The database is composed from observations of the following datasets: NOMAD, SeaBASS, MERMAID, AERONET-OC, BOUSSOLE and HOTS. The result was a merged dataset tuned for the validation of satellite-derived <span class="hlt">ocean</span> colour products. This was an attempt to gather, homogenize and merge, a large high-quality bio-optical marine in situ data, as using all datasets in a single validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. An inter-comparison analysis between OC-CCI chlorophyll-a product and satellite pre-cursor datasets was done with single missions and merged single mission products. Single mission datasets considered were SeaWiFS, MODIS-Aqua and MERIS; merged mission datasets were obtained from the GlobColour (GC) as well as the Making Earth Science</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110007785&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110007785&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Interactions Between Mineral Dust, <span class="hlt">Climate</span>, and <span class="hlt">Ocean</span> Ecosystems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gasso, Santiago; Grassian, Vicki H.; Miller, Ron L.</p> <p>2010-01-01</p> <p>Over the past decade, technological improvements in the chemical and physical characterization of dust have provided insights into a number of phenomena that were previously unknown or poorly understood. In addition, <span class="hlt">models</span> are now incorporating a wider range of physical processes, which will allow us to better quantify the <span class="hlt">climatic</span> and ecological impacts of dust. For example, some <span class="hlt">models</span> include the effect of dust on <span class="hlt">oceanic</span> photosynthesis and thus on atmospheric CO 2 (Friedlingstein et al. 2006). The impact of long-range dust transport, with its multiple forcings and feedbacks, is a relatively new and complex area of research, where input from several disciplines is needed. So far, many of these effects have only been parameterized in <span class="hlt">models</span> in very simple terms. For example, the representation of dust sources remains a major uncertainty in dust <span class="hlt">modeling</span> and estimates of the global mass of airborne dust. This is a problem where Earth scientists could make an important contribution, by working with <span class="hlt">climate</span> scientists to determine the type of environments in which easily erodible soil particles might have accumulated over time. Geologists could also help to identify the predominant mineralogical composition of dust sources, which is crucial for calculating the radiative and chemical effects of dust but is currently known for only a few regions. Understanding how <span class="hlt">climate</span> and geological processes control source extent and characterizing the mineral content of airborne dust are two of the fascinating challenges in future dust research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC54A..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC54A..05K"><span>Geophysical Global <span class="hlt">Modeling</span> for Extreme Crop Production Using Photosynthesis <span class="hlt">Models</span> Coupled to <span class="hlt">Ocean</span> SST Dipoles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaneko, D.</p> <p>2016-12-01</p> <p><span class="hlt">Climate</span> change appears to have manifested itself along with abnormal meteorological disasters. Instability caused by drought and flood disasters is producing poor harvests because of poor photosynthesis and pollination. Fluctuations of extreme phenomena are increasing rapidly because amplitudes of change are much greater than average trends. A fundamental cause of these phenomena derives from increased stored energy inside <span class="hlt">ocean</span> waters. Geophysical and biochemical <span class="hlt">modeling</span> of crop production can elucidate complex mechanisms under seasonal <span class="hlt">climate</span> anomalies. The <span class="hlt">models</span> have progressed through their combination with global <span class="hlt">climate</span> reanalysis, environmental satellite data, and harvest data on the ground. This study examined adaptation of crop production to advancing abnormal phenomena related to global <span class="hlt">climate</span> change. Global environmental surface conditions, i.e., vegetation, surface air temperature, and sea surface temperature observed by satellites, enable global <span class="hlt">modeling</span> of crop production and monitoring. Basic streams of the concepts of <span class="hlt">modeling</span> rely upon continental energy flow and carbon circulation among crop vegetation, land surface atmosphere combining energy advection from <span class="hlt">ocean</span> surface anomalies. Global environmental surface conditions, e.g., vegetation, surface air temperature, and sea surface temperature observed by satellites, enable global <span class="hlt">modeling</span> of crop production and monitoring. The method of validating the <span class="hlt">modeling</span> relies upon carbon partitioning in biomass and grains through carbon flow by photosynthesis using carbon dioxide unit in photosynthesis. Results of computations done for this study show global distributions of actual evaporation, stomata opening, and photosynthesis, presenting mechanisms related to advection effects from SST anomalies in the Pacific, Atlantic, and Indian <span class="hlt">oceans</span> on global and continental croplands. For North America, <span class="hlt">climate</span> effects appear clearly in severe atmospheric phenomena, which have caused drought and forest fires</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3896211','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3896211"><span>Role of <span class="hlt">ocean</span> heat transport in <span class="hlt">climates</span> of tidally locked exoplanets around M dwarf stars</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Yongyun; Yang, Jun</p> <p>2014-01-01</p> <p>The distinctive feature of tidally locked exoplanets is the very uneven heating by stellar radiation between the dayside and nightside. Previous work has focused on the role of atmospheric heat transport in preventing atmospheric collapse on the nightside for terrestrial exoplanets in the habitable zone around M dwarfs. In the present paper, we carry out simulations with a fully coupled atmosphere–<span class="hlt">ocean</span> general circulation <span class="hlt">model</span> to investigate the role of <span class="hlt">ocean</span> heat transport in <span class="hlt">climate</span> states of tidally locked habitable exoplanets around M dwarfs. Our simulation results demonstrate that <span class="hlt">ocean</span> heat transport substantially extends the area of open water along the equator, showing a lobster-like spatial pattern of open water, instead of an “eyeball.” For sufficiently high-level greenhouse gases or strong stellar radiation, <span class="hlt">ocean</span> heat transport can even lead to complete deglaciation of the nightside. Our simulations also suggest that <span class="hlt">ocean</span> heat transport likely narrows the width of M dwarfs’ habitable zone. This study provides a demonstration of the importance of exooceanography in determining <span class="hlt">climate</span> states and habitability of exoplanets. PMID:24379386</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24379386','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24379386"><span>Role of <span class="hlt">ocean</span> heat transport in <span class="hlt">climates</span> of tidally locked exoplanets around M dwarf stars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Yongyun; Yang, Jun</p> <p>2014-01-14</p> <p>The distinctive feature of tidally locked exoplanets is the very uneven heating by stellar radiation between the dayside and nightside. Previous work has focused on the role of atmospheric heat transport in preventing atmospheric collapse on the nightside for terrestrial exoplanets in the habitable zone around M dwarfs. In the present paper, we carry out simulations with a fully coupled atmosphere-<span class="hlt">ocean</span> general circulation <span class="hlt">model</span> to investigate the role of <span class="hlt">ocean</span> heat transport in <span class="hlt">climate</span> states of tidally locked habitable exoplanets around M dwarfs. Our simulation results demonstrate that <span class="hlt">ocean</span> heat transport substantially extends the area of open water along the equator, showing a lobster-like spatial pattern of open water, instead of an "eyeball." For sufficiently high-level greenhouse gases or strong stellar radiation, <span class="hlt">ocean</span> heat transport can even lead to complete deglaciation of the nightside. Our simulations also suggest that <span class="hlt">ocean</span> heat transport likely narrows the width of M dwarfs' habitable zone. This study provides a demonstration of the importance of exooceanography in determining <span class="hlt">climate</span> states and habitability of exoplanets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A51H3126N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A51H3126N"><span>Simulations of the future precipitation <span class="hlt">climate</span> of the Central Andes using a coupled regional <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nicholls, S.; Mohr, K. I.</p> <p>2014-12-01</p> <p>The meridional extent and complex orography of the South American continent contributes to a wide diversity of <span class="hlt">climate</span> regimes ranging from hyper-arid deserts to tropical rainforests to sub-polar highland regions. Global <span class="hlt">climate</span> <span class="hlt">models</span>, although capable of resolving synoptic-scale South American <span class="hlt">climate</span> features, are inadequate for fully-resolving the strong gradients between <span class="hlt">climate</span> regimes and the complex orography which define the Tropical Andes given their low spatial and temporal resolution. Recent computational advances now make practical regional <span class="hlt">climate</span> <span class="hlt">modeling</span> with prognostic mesoscale atmosphere-<span class="hlt">ocean</span> coupled <span class="hlt">models</span>, such as the Coupled <span class="hlt">Ocean</span>-Atmosphere-Wave-Sediment Transport (COAWST) <span class="hlt">modeling</span> system, to <span class="hlt">climate</span> research. Previous work has shown COAWST to reasonably simulate the both the entire 2003-2004 wet season (Dec-Feb) as validated against both satellite and <span class="hlt">model</span> analysis data. More recently, COAWST simulations have also been shown to sensibly reproduce the entire annual cycle of rainfall (Oct 2003 - Oct 2004) with historical <span class="hlt">climate</span> <span class="hlt">model</span> input. Using future global <span class="hlt">climate</span> <span class="hlt">model</span> input for COAWST, the present work involves year-long cycle spanning October to October for the years 2031, 2059, and 2087 assuming the most likely regional <span class="hlt">climate</span> pathway (RCP): RCP 6.0. COAWST output is used to investigate how global <span class="hlt">climate</span> change impacts the spatial distribution, precipitation rates, and diurnal cycle of precipitation patterns in the Central Andes vary in these yearly "snapshots". Initial results show little change to precipitation coverage or its diurnal cycle, however precipitation amounts did tend drier over the Brazilian Plateau and wetter over the Western Amazon and Central Andes. These results suggest potential adjustments to large-scale <span class="hlt">climate</span> features (such as the Bolivian High).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27245575','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27245575"><span>Multi-<span class="hlt">model</span> attribution of upper-<span class="hlt">ocean</span> temperature changes using an isothermal approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weller, Evan; Min, Seung-Ki; Palmer, Matthew D; Lee, Donghyun; Yim, Bo Young; Yeh, Sang-Wook</p> <p>2016-06-01</p> <p>Both air-sea heat exchanges and changes in <span class="hlt">ocean</span> advection have contributed to observed upper-<span class="hlt">ocean</span> warming most evident in the late-twentieth century. However, it is predominantly via changes in air-sea heat fluxes that human-induced <span class="hlt">climate</span> forcings, such as increasing greenhouse gases, and other natural factors such as volcanic aerosols, have influenced global <span class="hlt">ocean</span> heat content. The present study builds on previous work using two different indicators of upper-<span class="hlt">ocean</span> temperature changes for the detection of both anthropogenic and natural external <span class="hlt">climate</span> forcings. Using simulations from phase 5 of the Coupled <span class="hlt">Model</span> Intercomparison Project, we compare mean temperatures above a fixed isotherm with the more widely adopted approach of using a fixed depth. We present the first multi-<span class="hlt">model</span> ensemble detection and attribution analysis using the fixed isotherm approach to robustly detect both anthropogenic and natural external influences on upper-<span class="hlt">ocean</span> temperatures. Although contributions from multidecadal natural variability cannot be fully removed, both the large multi-<span class="hlt">model</span> ensemble size and properties of the isotherm analysis reduce internal variability of the <span class="hlt">ocean</span>, resulting in better observation-<span class="hlt">model</span> comparison of temperature changes since the 1950s. We further show that the high temporal resolution afforded by the isotherm analysis is required to detect natural external influences such as volcanic cooling events in the upper-<span class="hlt">ocean</span> because the radiative effect of volcanic forcings is short-lived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...626926W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...626926W"><span>Multi-<span class="hlt">model</span> attribution of upper-<span class="hlt">ocean</span> temperature changes using an isothermal approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weller, Evan; Min, Seung-Ki; Palmer, Matthew D.; Lee, Donghyun; Yim, Bo Young; Yeh, Sang-Wook</p> <p>2016-06-01</p> <p>Both air-sea heat exchanges and changes in <span class="hlt">ocean</span> advection have contributed to observed upper-<span class="hlt">ocean</span> warming most evident in the late-twentieth century. However, it is predominantly via changes in air-sea heat fluxes that human-induced <span class="hlt">climate</span> forcings, such as increasing greenhouse gases, and other natural factors such as volcanic aerosols, have influenced global <span class="hlt">ocean</span> heat content. The present study builds on previous work using two different indicators of upper-<span class="hlt">ocean</span> temperature changes for the detection of both anthropogenic and natural external <span class="hlt">climate</span> forcings. Using simulations from phase 5 of the Coupled <span class="hlt">Model</span> Intercomparison Project, we compare mean temperatures above a fixed isotherm with the more widely adopted approach of using a fixed depth. We present the first multi-<span class="hlt">model</span> ensemble detection and attribution analysis using the fixed isotherm approach to robustly detect both anthropogenic and natural external influences on upper-<span class="hlt">ocean</span> temperatures. Although contributions from multidecadal natural variability cannot be fully removed, both the large multi-<span class="hlt">model</span> ensemble size and properties of the isotherm analysis reduce internal variability of the <span class="hlt">ocean</span>, resulting in better observation-<span class="hlt">model</span> comparison of temperature changes since the 1950s. We further show that the high temporal resolution afforded by the isotherm analysis is required to detect natural external influences such as volcanic cooling events in the upper-<span class="hlt">ocean</span> because the radiative effect of volcanic forcings is short-lived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006GeoRL..3319701F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006GeoRL..3319701F"><span>Southern <span class="hlt">Ocean</span> warming due to human influence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fyfe, John C.</p> <p>2006-10-01</p> <p>I show that the latest series of <span class="hlt">climate</span> <span class="hlt">models</span> reproduce the observed mid-depth Southern <span class="hlt">Ocean</span> warming since the 1950s if they include time-varying changes in anthropogenic greenhouse gases, sulphate aerosols and volcanic aerosols in the Earth's atmosphere. The remarkable agreement between observations and state-of-the art <span class="hlt">climate</span> <span class="hlt">models</span> suggests significant human influence on Southern <span class="hlt">Ocean</span> temperatures. I also show that <span class="hlt">climate</span> <span class="hlt">models</span> that do not include volcanic aerosols produce mid-depth Southern <span class="hlt">Ocean</span> warming that is nearly double that produced by <span class="hlt">climate</span> <span class="hlt">models</span> that do include volcanic aerosols. This implies that the full effect of human-induced warming of the Southern <span class="hlt">Ocean</span> may yet to be realized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JSCER..67..134T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JSCER..67..134T"><span>SEEPLUS: A SIMPLE ONLINE <span class="hlt">CLIMATE</span> <span class="hlt">MODEL</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsutsui, Junichi</p> <p></p> <p>A web application for a simple <span class="hlt">climate</span> <span class="hlt">model</span> - SEEPLUS (a Simple <span class="hlt">climate</span> <span class="hlt">model</span> to Examine Emission Pathways Leading to Updated Scenarios) - has been developed. SEEPLUS consists of carbon-cycle and <span class="hlt">climate</span>-change modules, through which it provides the information infrastructure required to perform <span class="hlt">climate</span>-change experiments, even on a millennial-timescale. The main objective of this application is to share the latest scientific knowledge acquired from <span class="hlt">climate</span> <span class="hlt">modeling</span> studies among the different stakeholders involved in <span class="hlt">climate</span>-change issues. Both the carbon-cycle and <span class="hlt">climate</span>-change modules employ impulse response functions (IRFs) for their key processes, thereby enabling the <span class="hlt">model</span> to integrate the outcome from an ensemble of complex <span class="hlt">climate</span> <span class="hlt">models</span>. The current IRF parameters and forcing manipulation are basically consistent with, or within an uncertainty range of, the understanding of certain key aspects such as the equivalent <span class="hlt">climate</span> sensitivity and <span class="hlt">ocean</span> CO2 uptake data documented in representative literature. The carbon-cycle module enables inverse calculation to determine the emission pathway required in order to attain a given concentration pathway, thereby providing a flexible way to compare the module with more advanced <span class="hlt">modeling</span> studies. The module also enables analytical evaluation of its equilibrium states, thereby facilitating the long-term planning of global warming mitigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013285','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013285"><span>Combining Satellite and in Situ Data with <span class="hlt">Models</span> to Support <span class="hlt">Climate</span> Data Records in <span class="hlt">Ocean</span> Biology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gregg, Watson</p> <p>2011-01-01</p> <p>The satellite <span class="hlt">ocean</span> color data record spans multiple decades and, like most long-term satellite observations of the Earth, comes from many sensors. Unfortunately, global and regional chlorophyll estimates from the overlapping missions show substantial biases, limiting their use in combination to construct consistent data records. SeaWiFS and MODIS-Aqua differed by 13% globally in overlapping time segments, 2003-2007. For perspective, the maximum change in annual means over the entire Sea WiFS mission era was about 3%, and this included an El NinoLa Nina transition. These discrepancies lead to different estimates of trends depending upon whether one uses SeaWiFS alone for the 1998-2007 (no significant change), or whether MODIS is substituted for the 2003-2007 period (18% decline, P less than 0.05). Understanding the effects of <span class="hlt">climate</span> change on the global <span class="hlt">oceans</span> is difficult if different satellite data sets cannot be brought into conformity. The differences arise from two causes: 1) different sensors see chlorophyll differently, and 2) different sensors see different chlorophyll. In the first case, differences in sensor band locations, bandwidths, sensitivity, and time of observation lead to different estimates of chlorophyll even from the same location and day. In the second, differences in orbit and sensitivities to aerosols lead to sampling differences. A new approach to <span class="hlt">ocean</span> color using in situ data from the public archives forces different satellite data to agree to within interannual variability. The global difference between Sea WiFS and MODIS is 0.6% for 2003-2007 using this approach. It also produces a trend using the combination of SeaWiFS and MODIS that agrees with SeaWiFS alone for 1998-2007. This is a major step to reducing errors produced by the first cause, sensor-related discrepancies. For differences that arise from sampling, data assimilation is applied. The underlying geographically complete fields derived from a free-running <span class="hlt">model</span> is unaffected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920016878','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920016878"><span>The future of spaceborne altimetry. <span class="hlt">Oceans</span> and <span class="hlt">climate</span> change: A long-term strategy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koblinsky, C. J. (Editor); Gaspar, P. (Editor); Lagerloef, G. (Editor)</p> <p>1992-01-01</p> <p>The <span class="hlt">ocean</span> circulation and polar ice sheet volumes provide important memory and control functions in the global <span class="hlt">climate</span>. Their long term variations are unknown and need to be understood before meaningful appraisals of <span class="hlt">climate</span> change can be made. Satellite altimetry is the only method for providing global information on the <span class="hlt">ocean</span> circulation and ice sheet volume. A robust altimeter measurement program is planned which will initiate global observations of the <span class="hlt">ocean</span> circulation and polar ice sheets. In order to provide useful data about the <span class="hlt">climate</span>, these measurements must be continued with unbroken coverage into the next century. Herein, past results of the role of the <span class="hlt">ocean</span> in the <span class="hlt">climate</span> system is summarized, near term goals are outlined, and requirements and options are presented for future altimeter missions. There are three basic scientific objectives for the program: <span class="hlt">ocean</span> circulation; polar ice sheets; and mean sea level change. The greatest scientific benefit will be achieved with a series of dedicated high precision altimeter spacecraft, for which the choice of orbit parameters and system accuracy are unencumbered by requirements of companion instruments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28586678','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28586678"><span>Polar <span class="hlt">oceans</span> in a changing <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barnes, David K A; Tarling, Geraint A</p> <p>2017-06-05</p> <p>Most of Earth's surface is blue or white, but how much of each would depend on the time of observation. Our planet has been through phases of snowball (all frozen), greenhouse (all liquid seas) and icehouse (frozen and liquid). Even during current icehouse conditions, the extent of ice versus water has changed considerably between ice ages and interglacial periods. Water has been vital for life on Earth and has driven and been influenced by transitions between greenhouse and icehouse. However, neither the possession of water nor having liquid and frozen seas are unique to Earth (Figure 1). Frozen water <span class="hlt">oceans</span> on the moons Enceladus and Europa (and possibly others) and the liquid and frozen hydrocarbon <span class="hlt">oceans</span> on Titan probably represent the most likely areas to find extraterrestrial life. We know very little about life in Earth's polar <span class="hlt">oceans</span>, yet they are the engine of the thermohaline 'conveyor-belt', driving global circulation of heat, oxygen, carbon and nutrients as well as setting sea level through change in ice-mass balance. In regions of polar seas, where surface water is particularly cold and dense, it sinks to generate a tropic-ward flow on the <span class="hlt">ocean</span> floor of the Pacific, Atlantic and Indian <span class="hlt">Oceans</span>. Cold water holds more gas, so this sinking water exports O 2 and nutrients, thereby supporting life in the deep sea, as well as soaking up CO 2 from the atmosphere. Water from mid-depths at lower latitudes flows in to replace the sinking polar surface water. This brings heat. The poles are cold because they receive the least energy from the sun, and this extreme light <span class="hlt">climate</span> varies on many different time scales. To us, the current warm, interglacial conditions seem normal, yet such phases have represented only ∼10% of Homo sapiens' existence. Variations in Earth's orbit (so called 'Milankovitch cycles') have driven cyclical alternation of glaciations (ice ages) and warmer interglacials. Despite this, Earth's polar regions have been our planet's most</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26081243','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26081243"><span>Disciplinary reporting affects the interpretation of <span class="hlt">climate</span> change impacts in global <span class="hlt">oceans</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hauser, Donna D W; Tobin, Elizabeth D; Feifel, Kirsten M; Shah, Vega; Pietri, Diana M</p> <p>2016-01-01</p> <p><span class="hlt">Climate</span> change is affecting marine ecosystems, but different investigative approaches in physical, chemical, and biological disciplines may influence interpretations of <span class="hlt">climate</span>-driven changes in the <span class="hlt">ocean</span>. Here, we review the <span class="hlt">ocean</span> change literature from 2007 to 2012 based on 461 of the most highly cited studies in physical and chemical oceanography and three biological subdisciplines. Using highly cited studies, we focus on research that has shaped recent discourse on <span class="hlt">climate</span>-driven <span class="hlt">ocean</span> change. Our review identified significant differences in spatial and temporal scales of investigation among disciplines. Physical/chemical studies had a median duration of 29 years (n = 150) and covered the greatest study areas (median 1.41 × 10(7) km(2) , n = 148). Few biological studies were conducted over similar spatial and temporal scales (median 8 years, n = 215; median 302 km(2) , n = 196), suggesting a more limited ability to separate <span class="hlt">climate</span>-related responses from natural variability. We linked physical/chemical and biological disciplines by tracking studies examining biological responses to changing <span class="hlt">ocean</span> conditions. Of the 545 biological responses recorded, a single physical or chemical stressor was usually implicated as the cause (59%), with temperature as the most common primary stressor (44%). The most frequently studied biological responses were changes in physiology (31%) and population abundance (30%). Differences in disciplinary studies, as identified in this review, can ultimately influence how researchers interpret <span class="hlt">climate</span>-related impacts in marine systems. We identified research gaps and the need for more discourse in (1) the Indian and other Southern Hemisphere <span class="hlt">ocean</span> basins; (2) research themes such as archaea, bacteria, viruses, mangroves, turtles, and <span class="hlt">ocean</span> acidification; (3) physical and chemical stressors such as dissolved oxygen, salinity, and upwelling; and (4) adaptive responses of marine organisms to <span class="hlt">climate</span>-driven <span class="hlt">ocean</span> change. Our findings reveal</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910005371','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910005371"><span><span class="hlt">Climate</span> and atmospheric <span class="hlt">modeling</span> studies. <span class="hlt">Climate</span> applications of Earth and planetary observations. Chemistry of Earth and environment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1990-01-01</p> <p>The research conducted during the past year in the <span class="hlt">climate</span> and atmospheric <span class="hlt">modeling</span> programs concentrated on the development of appropriate atmospheric and upper <span class="hlt">ocean</span> <span class="hlt">models</span>, and preliminary applications of these <span class="hlt">models</span>. Principal <span class="hlt">models</span> are a one-dimensional radiative-convective <span class="hlt">model</span>, a three-dimensional global <span class="hlt">climate</span> <span class="hlt">model</span>, and an upper <span class="hlt">ocean</span> <span class="hlt">model</span>. Principal applications have been the study of the impact of CO2, aerosols and the solar 'constant' on <span class="hlt">climate</span>. Progress was made in the 3-D <span class="hlt">model</span> development towards physically realistic treatment of these processes. In particular, a map of soil classifications on 1 degree x 1 degree resolution has been digitized, and soil properties have been assigned to each soil type. Using this information about soil properties, a method was developed to simulate the hydraulic behavior of soils of the world. This improved treatment of soil hydrology, together with the seasonally varying vegetation cover, will provide a more realistic study of the role of the terrestrial biota in <span class="hlt">climate</span> change. A new version of the <span class="hlt">climate</span> <span class="hlt">model</span> was created which follows the isotopes of water and sources of water (or colored water) throughout the planet. Each isotope or colored water source is a fraction of the <span class="hlt">climate</span> <span class="hlt">model</span>'s water. It participates in condensation and surface evaporation at different fractionation rates and is transported by the dynamics. A major benefit of this project has been to improve the programming techniques and physical simulation of the water vapor budget of the <span class="hlt">climate</span> <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1015083-desert-dust-anthropogenic-aerosol-interactions-community-climate-system-model-coupled-carbon-climate-model','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1015083-desert-dust-anthropogenic-aerosol-interactions-community-climate-system-model-coupled-carbon-climate-model"><span>Desert dust and anthropogenic aerosol interactions in the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> coupled-carbon-<span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mahowald, Natalie; Rothenberg, D.; Lindsay, Keith</p> <p>2011-02-01</p> <p>Coupled-carbon-<span class="hlt">climate</span> simulations are an essential tool for predicting the impact of human activity onto the <span class="hlt">climate</span> and biogeochemistry. Here we incorporate prognostic desert dust and anthropogenic aerosols into the CCSM3.1 coupled carbon-<span class="hlt">climate</span> <span class="hlt">model</span> and explore the resulting interactions with <span class="hlt">climate</span> and biogeochemical dynamics through a series of transient anthropogenic simulations (20th and 21st centuries) and sensitivity studies. The inclusion of prognostic aerosols into this <span class="hlt">model</span> has a small net global cooling effect on <span class="hlt">climate</span> but does not significantly impact the globally averaged carbon cycle; we argue that this is likely to be because the CCSM3.1 <span class="hlt">model</span> has a small climatemore » feedback onto the carbon cycle. We propose a mechanism for including desert dust and anthropogenic aerosols into a simple carbon-<span class="hlt">climate</span> feedback analysis to explain the results of our and previous studies. Inclusion of aerosols has statistically significant impacts on regional <span class="hlt">climate</span> and biogeochemistry, in particular through the effects on the <span class="hlt">ocean</span> nitrogen cycle and primary productivity of altered iron inputs from desert dust deposition.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27365315','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27365315"><span>North Atlantic <span class="hlt">ocean</span> circulation and abrupt <span class="hlt">climate</span> change during the last glaciation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Henry, L G; McManus, J F; Curry, W B; Roberts, N L; Piotrowski, A M; Keigwin, L D</p> <p>2016-07-29</p> <p>The most recent ice age was characterized by rapid and hemispherically asynchronous <span class="hlt">climate</span> oscillations, whose origin remains unresolved. Variations in <span class="hlt">oceanic</span> meridional heat transport may contribute to these repeated <span class="hlt">climate</span> changes, which were most pronounced during marine isotope stage 3, the glacial interval 25 thousand to 60 thousand years ago. We examined <span class="hlt">climate</span> and <span class="hlt">ocean</span> circulation proxies throughout this interval at high resolution in a deep North Atlantic sediment core, combining the kinematic tracer protactinium/thorium (Pa/Th) with the deep water-mass tracer, epibenthic δ(13)C. These indicators suggest reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning. These results provide direct evidence for the <span class="hlt">ocean</span>'s persistent, central role in abrupt glacial <span class="hlt">climate</span> change. Copyright © 2016, American Association for the Advancement of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1060008','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1060008"><span>Do Coupled <span class="hlt">Climate</span> <span class="hlt">Models</span> Correctly SImulate the Upward Branch of the Deept <span class="hlt">Ocean</span> Global Conveyor?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sarmiento, Jorge L; Downes, Stephanie; Bianchi, Daniele</p> <p></p> <p>The large-scale meridional overturning circulation (MOC) connects the deep <span class="hlt">ocean</span>, a major reservoir of carbon, to the other components of the <span class="hlt">climate</span> system and must therefore be accurately represented in Earth System <span class="hlt">Models</span>. Our project aims to address the specific question of the pathways and mechanisms controlling the upwelling branch of the MOC, a subject of significant disagreement between <span class="hlt">models</span> and observational syntheses, and among general circulation <span class="hlt">models</span>. Observations of these pathways are limited, particularly in regions of complex hydrography such as the Southern <span class="hlt">Ocean</span>. As such, we rely on <span class="hlt">models</span> to examine theories of the overturning circulation, both physicallymore » and biogeochemically. This grant focused on a particular aspect of the meridional overturning circulation (MOC) where there is currently significant disagreement between <span class="hlt">models</span> and observationally based analyses of the MOC, and amongst general circulation <span class="hlt">models</span>. In particular, the research focused on addressing the following questions: 1. Where does the deep water that sinks in the polar regions rise to the surface? 2. What processes are responsible for this rise? 3. Do state-of-the-art coupled GCMs capture these processes? Our research had three key components: observational synthesis, <span class="hlt">model</span> development and <span class="hlt">model</span> analysis. In this final report we outline the key results from these areas of research for the 2007 to 2012 grant period. The research described here was carried out primarily by graduate student, Daniele Bianchi (now a Postdoc at McGill University, Canada), and Postdoc Stephanie Downes (now a Research Fellow at The Australian national University, Australia). Additional support was provided for programmers Jennifer Simeon as well as Rick Slater.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080022184&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080022184&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Seasonal Correlations of SST, Water Vapor, and Convective Activity in Tropical <span class="hlt">Oceans</span>: A New Hyperspectral Data Set for <span class="hlt">Climate</span> <span class="hlt">Model</span> Testing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aumann, Hartmut H.; Gregorich, David T.; Broberg, Steven E.; Elliott, Denis A.</p> <p>2007-01-01</p> <p>The analysis of the response of the Earth <span class="hlt">Climate</span> System to the seasonal changes of solar forcing in the tropical <span class="hlt">oceans</span> using four years of the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) data between 2002 and 2006 gives new insight into amplitude and phase relationships between surface and tropospheric temperatures, humidity, and convective activity. The intensity of the convective activity is measured by counting deep convective clouds. The peaks of convective activity, temperature in the mid-troposphere, and water vapor in the 0 - 30 N and 0 - 30 S tropical <span class="hlt">ocean</span> zonal means occur about two months after solstice, all leading the peak of the sea surface temperature by several weeks. Phase is key to the evaluation of feedback. The evaluation of <span class="hlt">climate</span> <span class="hlt">models</span> in terms of zonal and annual means and annual mean deviations from zonal means can now be supplemented by evaluating the phase of key atmospheric and surface parameters relative to solstice. The ability of <span class="hlt">climate</span> <span class="hlt">models</span> to reproduce the statistical flavor of the observed amplitudes and relative phases for broad zonal means should lead to increased confidence in the realism of their water vapor and cloud feedback algorithms. AIRS and AMSU were launched into a 705 km altitude polar sun-synchronous orbit on the EOS Aqua spacecraft on May 4, 2002, and have been in routine data gathering mode since September 2002.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080044777&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080044777&hterms=ocean+climate+changes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Docean%2Bclimate%2Bchanges"><span>Seasonal Correlations of SST, Water Vapor, and Convective Activity in Tropical <span class="hlt">Oceans</span>: A New Hyperspectral Data Set for <span class="hlt">Climate</span> <span class="hlt">Model</span> Testing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aumann, Hartmut H.; Gregorich, David T.; Broberg, Steven E.; Elliott, Denis A.</p> <p>2007-01-01</p> <p>The analysis of the response of the Earth <span class="hlt">Climate</span> System to the seasonal changes of solar forcing in the tropical <span class="hlt">oceans</span> using four years of the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) data between 2002 and 2006 gives new insight into amplitude and phase relationships between surface and tropospheric temperatures, humidity, and convective activity. The intensity of the convective activity is measured by counting deep convective clouds. The peaks of convective activity, temperature in the mid-troposphere, and water vapor in the 0-30 N and 0-30 S tropical <span class="hlt">ocean</span> zonal means occur about two months after solstice, all leading the peak of the sea surface temperature by several weeks. Phase is key to the evaluation of feedback. The evaluation of <span class="hlt">climate</span> <span class="hlt">models</span> in terms of zonal and annual means and annual mean deviations from zonal means can now be supplemented by evaluating the phase of key atmospheric and surface parameters relative to solstice. The ability of <span class="hlt">climate</span> <span class="hlt">models</span> to reproduce the statistical flavor of the observed amplitudes and relative phases for broad zonal means should lead to increased confidence in the realism of their water vapor and cloud feedback algorithms. AIRS and AMSU were launched into a 705 km altitude polar sun-synchronous orbit on the EOS Aqua spacecraft on May 4, 2002, and have been in routine data gathering mode since September 2002.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70030709','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70030709"><span>GFDL's CM2 global coupled <span class="hlt">climate</span> <span class="hlt">models</span>. Part I: Formulation and simulation characteristics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Delworth, T.L.; Broccoli, A.J.; Rosati, A.; Stouffer, R.J.; Balaji, V.; Beesley, J.A.; Cooke, W.F.; Dixon, K.W.; Dunne, J.; Dunne, K.A.; Durachta, J.W.; Findell, K.L.; Ginoux, P.; Gnanadesikan, A.; Gordon, C.T.; Griffies, S.M.; Gudgel, R.; Harrison, M.J.; Held, I.M.; Hemler, R.S.; Horowitz, L.W.; Klein, S.A.; Knutson, T.R.; Kushner, P.J.; Langenhorst, A.R.; Lee, H.-C.; Lin, S.-J.; Lu, J.; Malyshev, S.L.; Milly, P.C.D.; Ramaswamy, V.; Russell, J.; Schwarzkopf, M.D.; Shevliakova, E.; Sirutis, J.J.; Spelman, M.J.; Stern, W.F.; Winton, M.; Wittenberg, A.T.; Wyman, B.; Zeng, F.; Zhang, R.</p> <p>2006-01-01</p> <p>The formulation and simulation characteristics of two new global coupled <span class="hlt">climate</span> <span class="hlt">models</span> developed at NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) are described. The <span class="hlt">models</span> were designed to simulate atmospheric and <span class="hlt">oceanic</span> <span class="hlt">climate</span> and variability from the diurnal time scale through multicentury <span class="hlt">climate</span> change, given our computational constraints. In particular, an important goal was to use the same <span class="hlt">model</span> for both experimental seasonal to interannual forecasting and the study of multicentury global <span class="hlt">climate</span> change, and this goal has been achieved. Tw o versions of the coupled <span class="hlt">model</span> are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and <span class="hlt">ocean</span> components. For both coupled <span class="hlt">models</span>, the resolution of the land and atmospheric components is 2?? latitude ?? 2.5?? longitude; the atmospheric <span class="hlt">model</span> has 24 vertical levels. The <span class="hlt">ocean</span> resolution is 1?? in latitude and longitude, with meridional resolution equatorward of 30?? becoming progressively finer, such that the meridional resolution is 1/3?? at the equator. There are 50 vertical levels in the <span class="hlt">ocean</span>, with 22 evenly spaced levels within the top 220 m. The <span class="hlt">ocean</span> component has poles over North America and Eurasia to avoid polar filtering. Neither coupled <span class="hlt">model</span> employs flux adjustments. The co ntrol simulations have stable, realistic <span class="hlt">climates</span> when integrated over multiple centuries. Both <span class="hlt">models</span> have simulations of ENSO that are substantially improved relative to previous GFDL coupled <span class="hlt">models</span>. The CM2.0 <span class="hlt">model</span> has been further evaluated as an ENSO forecast <span class="hlt">model</span> and has good skill (CM2.1 has not been evaluated as an ENSO forecast <span class="hlt">model</span>). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in <span class="hlt">oceanic</span> gyre circulations; 2) changes in cloud tuning and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14999278','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14999278"><span>Polar <span class="hlt">ocean</span> stratification in a cold <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sigman, Daniel M; Jaccard, Samuel L; Haug, Gerald H</p> <p>2004-03-04</p> <p>The low-latitude <span class="hlt">ocean</span> is strongly stratified by the warmth of its surface water. As a result, the great volume of the deep <span class="hlt">ocean</span> has easiest access to the atmosphere through the polar surface <span class="hlt">ocean</span>. In the modern polar <span class="hlt">ocean</span> during the winter, the vertical distribution of temperature promotes overturning, with colder water over warmer, while the salinity distribution typically promotes stratification, with fresher water over saltier. However, the sensitivity of seawater density to temperature is reduced as temperature approaches the freezing point, with potential consequences for global <span class="hlt">ocean</span> circulation under cold <span class="hlt">climates</span>. Here we present deep-sea records of biogenic opal accumulation and sedimentary nitrogen isotopic composition from the Subarctic North Pacific <span class="hlt">Ocean</span> and the Southern <span class="hlt">Ocean</span>. These records indicate that vertical stratification increased in both northern and southern high latitudes 2.7 million years ago, when Northern Hemisphere glaciation intensified in association with global cooling during the late Pliocene epoch. We propose that the cooling caused this increased stratification by weakening the role of temperature in polar <span class="hlt">ocean</span> density structure so as to reduce its opposition to the stratifying effect of the vertical salinity distribution. The shift towards stratification in the polar <span class="hlt">ocean</span> 2.7 million years ago may have increased the quantity of carbon dioxide trapped in the abyss, amplifying the global cooling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998ClDy...14..291S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998ClDy...14..291S"><span>A flexible <span class="hlt">climate</span> <span class="hlt">model</span> for use in integrated assessments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokolov, A. P.; Stone, P. H.</p> <p></p> <p>Because of significant uncertainty in the behavior of the <span class="hlt">climate</span> system, evaluations of the possible impact of an increase in greenhouse gas concentrations in the atmosphere require a large number of long-term <span class="hlt">climate</span> simulations. Studies of this kind are impossible to carry out with coupled atmosphere <span class="hlt">ocean</span> general circulation <span class="hlt">models</span> (AOGCMs) because of their tremendous computer resource requirements. Here we describe a two dimensional (zonally averaged) atmospheric <span class="hlt">model</span> coupled with a diffusive <span class="hlt">ocean</span> <span class="hlt">model</span> developed for use in the integrated framework of the Massachusetts Institute of Technology (MIT) Joint Program on the Science and Policy of Global Change. The 2-D <span class="hlt">model</span> has been developed from the Goddard Institute for Space Studies (GISS) GCM and includes parametrizations of all the main physical processes. This allows it to reproduce many of the nonlinear interactions occurring in simulations with GCMs. Comparisons of the results of present-day <span class="hlt">climate</span> simulations with observations show that the <span class="hlt">model</span> reasonably reproduces the main features of the zonally averaged atmospheric structure and circulation. The <span class="hlt">model</span>'s sensitivity can be varied by changing the magnitude of an inserted additional cloud feedback. Equilibrium responses of different versions of the 2-D <span class="hlt">model</span> to an instantaneous doubling of atmospheric CO2 are compared with results of similar simulations with different AGCMs. It is shown that the additional cloud feedback does not lead to any physically inconsistent results. On the contrary, changes in <span class="hlt">climate</span> variables such as precipitation and evaporation, and their dependencies on surface warming produced by different versions of the MIT 2-D <span class="hlt">model</span> are similar to those shown by GCMs. By choosing appropriate values of the deep <span class="hlt">ocean</span> diffusion coefficients, the transient behavior of different AOGCMs can be matched in simulations with the 2-D <span class="hlt">model</span>, with a unique choice of diffusion coefficients allowing one to match the performance of a given AOGCM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26564848','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26564848"><span><span class="hlt">Climate</span> change in the <span class="hlt">oceans</span>: Human impacts and responses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Allison, Edward H; Bassett, Hannah R</p> <p>2015-11-13</p> <p>Although it has far-reaching consequences for humanity, attention to <span class="hlt">climate</span> change impacts on the <span class="hlt">ocean</span> lags behind concern for impacts on the atmosphere and land. Understanding these impacts, as well as society's diverse perspectives and multiscale responses to the changing <span class="hlt">oceans</span>, requires a correspondingly diverse body of scholarship in the physical, biological, and social sciences and humanities. This can ensure that a plurality of values and viewpoints is reflected in the research that informs <span class="hlt">climate</span> policy and may enable the concerns of maritime societies and economic sectors to be heard in key adaptation and mitigation discussions. Copyright © 2015, American Association for the Advancement of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015733','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015733"><span>World <span class="hlt">Ocean</span> Circulation Experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clarke, R. Allyn</p> <p>1992-01-01</p> <p>The <span class="hlt">oceans</span> are an equal partner with the atmosphere in the global <span class="hlt">climate</span> system. The World <span class="hlt">Ocean</span> Circulation Experiment is presently being implemented to improve <span class="hlt">ocean</span> <span class="hlt">models</span> that are useful for <span class="hlt">climate</span> prediction both by encouraging more <span class="hlt">model</span> development but more importantly by providing quality data sets that can be used to force or to validate such <span class="hlt">models</span>. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global <span class="hlt">ocean</span> data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/442356-ncar-csm-ocean-model-ncar-oceanography-section-technical-note','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/442356-ncar-csm-ocean-model-ncar-oceanography-section-technical-note"><span>NCAR CSM <span class="hlt">ocean</span> <span class="hlt">model</span> by the NCAR oceanography section. Technical note</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>NONE</p> <p></p> <p>This technical note documents the <span class="hlt">ocean</span> component of the NCAR <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CSM). The <span class="hlt">ocean</span> code has been developed from the Modular <span class="hlt">Ocean</span> <span class="hlt">Model</span> (version 1.1) which was developed and maintained at the NOAA Geophysical Fluid Dynamics Laboratory in Princeton. As a tribute to Mike Cox, and because the material is still relevant, the first four sections of this technical note are a straight reproduction from the GFDL Technical Report that Mike wrote in 1984. The remaining sections document how the NCAR Oceanography Section members have developed the MOM 1.1 code, and how it is forced, in order tomore » produce the NCAR CSM <span class="hlt">Ocean</span> <span class="hlt">Model</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS23D..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS23D..01H"><span>Multi-decadal trend and space-time variability of sea level over the Indian <span class="hlt">Ocean</span> since the 1950s: impact of decadal <span class="hlt">climate</span> modes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, W.; Stammer, D.; Meehl, G. A.; Hu, A.; Sienz, F.</p> <p>2016-12-01</p> <p>Sea level varies on decadal and multi-decadal timescales over the Indian <span class="hlt">Ocean</span>. The variations are not spatially uniform, and can deviate considerably from the global mean sea level rise (SLR) due to various geophysical processes. One of these processes is the change of <span class="hlt">ocean</span> circulation, which can be partly attributed to natural internal modes of <span class="hlt">climate</span> variability. Over the Indian <span class="hlt">Ocean</span>, the most influential <span class="hlt">climate</span> modes on decadal and multi-decadal timescales are the Interdecadal Pacific Oscillation (IPO) and decadal variability of the Indian <span class="hlt">Ocean</span> dipole (IOD). Here, we first analyze observational datasets to investigate the impacts of IPO and IOD on spatial patterns of decadal and interdecadal (hereafter decal) sea level variability & multi-decadal trend over the Indian <span class="hlt">Ocean</span> since the 1950s, using a new statistical approach of Bayesian Dynamical Linear regression <span class="hlt">Model</span> (DLM). The Bayesian DLM overcomes the limitation of "time-constant (static)" regression coefficients in conventional multiple linear regression <span class="hlt">model</span>, by allowing the coefficients to vary with time and therefore measuring "time-evolving (dynamical)" relationship between <span class="hlt">climate</span> modes and sea level. For the multi-decadal sea level trend since the 1950s, our results show that <span class="hlt">climate</span> modes and non-<span class="hlt">climate</span> modes (the part that cannot be explained by <span class="hlt">climate</span> modes) have comparable contributions in magnitudes but with different spatial patterns, with each dominating different regions of the Indian <span class="hlt">Ocean</span>. For decadal variability, <span class="hlt">climate</span> modes are the major contributors for sea level variations over most region of the tropical Indian <span class="hlt">Ocean</span>. The relative importance of IPO and decadal variability of IOD, however, varies spatially. For example, while IOD decadal variability dominates IPO in the eastern equatorial basin (85E-100E, 5S-5N), IPO dominates IOD in causing sea level variations in the tropical southwest Indian <span class="hlt">Ocean</span> (45E-65E, 12S-2S). To help decipher the possible contribution of external</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020046683','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020046683"><span>Comparison of Mean <span class="hlt">Climate</span> Trends in the Northern Hemisphere Between N.C.E.P. and Two Atmosphere-<span class="hlt">Ocean</span> <span class="hlt">Model</span> Forced Runs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lucarini, Valerio; Russell, Gary L.; Hansen, James E. (Technical Monitor)</p> <p>2002-01-01</p> <p>Results are presented for two greenhouse gas experiments of the Goddard Institute for Space Studies Atmosphere-<span class="hlt">Ocean</span> <span class="hlt">Model</span> (AOM). The computed trends of surface pressure, surface temperature, 850, 500 and 200 mb geopotential heights and related temperatures of the <span class="hlt">model</span> for the time frame 1960-2000 are compared to those obtained from the National Centers for Environmental Prediction observations. A spatial correlation analysis and mean value comparison are performed, showing good agreement. A brief general discussion about the statistics of trend detection is presented. The domain of interest is the Northern Hemisphere (NH) because of the higher reliability of both the <span class="hlt">model</span> results and the observations. The accuracy that this AOM has in describing the observed regional and NH <span class="hlt">climate</span> trends makes it reliable in forecasting future <span class="hlt">climate</span> changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19965473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19965473"><span><span class="hlt">Climate</span>-driven basin-scale decadal oscillations of <span class="hlt">oceanic</span> phytoplankton.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martinez, Elodie; Antoine, David; D'Ortenzio, Fabrizio; Gentili, Bernard</p> <p>2009-11-27</p> <p>Phytoplankton--the microalgae that populate the upper lit layers of the <span class="hlt">ocean</span>--fuel the <span class="hlt">oceanic</span> food web and affect <span class="hlt">oceanic</span> and atmospheric carbon dioxide levels through photosynthetic carbon fixation. Here, we show that multidecadal changes in global phytoplankton abundances are related to basin-scale oscillations of the physical <span class="hlt">ocean</span>, specifically the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation. This relationship is revealed in approximately 20 years of satellite observations of chlorophyll and sea surface temperature. Interaction between the main pycnocline and the upper <span class="hlt">ocean</span> seasonal mixed layer is one mechanism behind this correlation. Our findings provide a context for the interpretation of contemporary changes in global phytoplankton and should improve predictions of their future evolution with <span class="hlt">climate</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918029H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918029H"><span>Using annually-resolved bivalve records and biogeochemical <span class="hlt">models</span> to understand and predict <span class="hlt">climate</span> impacts in coastal <span class="hlt">oceans</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holmes, Sarah</p> <p>2017-04-01</p> <p>It is more important than ever to study the <span class="hlt">oceans</span> and especially the shelf seas, which are disproportionately productive, sustaining over 90% of global fisheries . The economic and societal significance of these shallow <span class="hlt">oceans</span>, as the interface through which society interacts with the marine environment, makes them highly relevant to the decisions of policy-makers and stakeholders. These decision-makers rely upon empirical data informed by consistent and extensive monitoring and assessment from experts in the field, yet long-term, spatially-extensive datasets of the marine environment do not exist or are of poor quality. <span class="hlt">Modelling</span> the shelf seas with biogeochemical <span class="hlt">models</span> can provide valuable data, allowing scientists to look at both past and future scenarios to estimate ecosystem response to change. In particular, the European Regional Sea Ecosystem <span class="hlt">Model</span> or ERSEM combines not only the complex hydrographical aspects of the North West European shelf, but also vast numbers of biological and chemical parameters. Though huge efforts across the <span class="hlt">modelling</span> community are invested into developing and ultimately increasing the reliability of <span class="hlt">models</span> such as the ERSEM, this is typically achieved by looking at relationships with aforementioned observed datasets, restricting <span class="hlt">model</span> accuracy and our understanding of ecosystem processes. It is for this reason that proxy data of the marine environment is so valuable. Of all marine proxies available, sclerochronology, the study of the growth bands on long-lived marine molluscs, is the only proven to provide novel, high resolution, multi-centennial, annually-resolved, absolutely-dated archives of past <span class="hlt">ocean</span> environment, analogous to dendrochronology. For the first time, this PhD project will combine the proxy data of sclerochronology with <span class="hlt">model</span> hindcast data from the ERSEM with the aim to better understand the North West European shelf sea environment and potentially improve predictions of future <span class="hlt">climate</span> change in this region and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP42A..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP42A..08H"><span>South African <span class="hlt">Climates</span>: Highlights From International <span class="hlt">Ocean</span> Discovery Program Expedition 361</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hemming, S. R.; Hall, I. R.; LeVay, L.</p> <p>2016-12-01</p> <p>International <span class="hlt">Ocean</span> Discovery Program Expedition 361 drilled six sites on the southeast African margin and in the Indian-Atlantic <span class="hlt">ocean</span> gateway, southwest Indian <span class="hlt">Ocean</span>, from 30 January to 31 March 2016. In total, 5175 m of core was recovered, with an average recovery of 102%, during 29.7 days of on-site operations. The sites, situated in the Mozambique Channel, at locations directly influenced by discharge from the Zambezi and Limpopo River catchments, the Natal Valley, the Agulhas Plateau, and the Cape Basin were targeted to reconstruct the history of the Greater Agulhas Current System over the past 5 Ma. The Agulhas Current transports 70 Sv of warm and saline surface waters from the tropical Indian <span class="hlt">Ocean</span> along the East African margin to the tip of Africa. Exchanges of heat and moisture with the atmosphere influence southern African rainfall patterns. Recent <span class="hlt">ocean</span> <span class="hlt">model</span> and paleoceanographic data further point at a potential role of the Agulhas Current in controlling the strength and mode of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Pleistocene. The main objectives of the expedition were to document the oceanographic properties of the Agulhas Current through tectonic and <span class="hlt">climatic</span> changes during the Plio-Pleistocene, to determine the dynamics of the Indian-Atlantic gateway circulation during this time, to examine the connection of the Agulhas leakage and AMOC, to address the influence of the Agulhas Current on African terrestrial <span class="hlt">climates</span> and potential links to Human evolution. Additionally, the Expedition set out to fulfill the needs of the Ancillary Project Letter, consisting of high-resolution interstitial water samples that will, and to constrain the temperature and salinity profiles of the <span class="hlt">ocean</span> during the Last Glacial Maximum. Here we highlight some of the expedition successes and show how it has made major strides toward fulfilling each of these objectives. The recovered sequences allowed complete spliced stratigraphic sections</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B31G..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B31G..01B"><span>Carbon Burial at the Land <span class="hlt">Ocean</span> Interface: <span class="hlt">Climate</span> vs Human Drivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bianchi, T. S.; Smeaton, C.; Cui, X.; Howe, J. A.; Austin, W.</p> <p>2017-12-01</p> <p>Fjords are connectors between the terrestrial and marine systems and are known as globally significant hotspots for the burial (Smith et al., 2014) and long-term storage (Smeaton et al., 2016) of carbon (C). The glacial geomorphology of fjords and their catchment results in the terrestrial and marine environments being strongly coupled more so than other estuary types. The clearest example of this is the terrestrial C subsidy to these sediment, it is estimated that globally 55-62% of C held in fjord sediments are terrestrially derived (Cui et al., 2016). Yet it is largely unknown how <span class="hlt">climatic</span> and human forcing drives the transfer of terrestrial C to marine sediments. Here we, examine the role of late Holocene <span class="hlt">climate</span> and human activity on the transfer of C from the terrestrial to marine environment along the North Atlantic Margin. Loch Sunart a Scottish fjord sits at the land <span class="hlt">ocean</span> interface of the North Atlantic. The catchment of the fjord has been shown to be sensitive to local and regional <span class="hlt">climatic</span> change (Gillibrand et al., 2005) and the fjord sediments have been able to record these changes in <span class="hlt">Climate</span> (Cage and Austin, 2010). Using a long (22 m) sedimentary record we discuss our understanding of mid to late Holocene regional <span class="hlt">climate</span> and its impact on terrestrial C transfer to the coastal <span class="hlt">ocean</span>. Alongside this we examine the role of humans on the landscape and their impact on the transfer of terrestrial C on the coastal <span class="hlt">ocean</span>. The results from this study will further our understanding of the long-term drivers of terrestrial C transfer to the coastal <span class="hlt">ocean</span>. Potentially this research provides insights on future C transfers under a changing future <span class="hlt">climate</span> allowing the importance of fjords as a <span class="hlt">climate</span> regulation service to be reassessed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMED34B..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMED34B..07M"><span>A <span class="hlt">Model</span> for Local Experiential Learning: Workshop on Mangroves, <span class="hlt">Oceans</span> & <span class="hlt">Climate</span> in Kosrae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maloney, A. E.; Sachs, J. P.; Barros, C.; Low, M.</p> <p>2015-12-01</p> <p>A curriculum for an intensive one-day workshop about mangroves, <span class="hlt">oceans</span>, and <span class="hlt">climate</span> has been developed for schoolteachers in the Federated States of Micronesia. The goals of the workshop are for teachers/attendees to be able to (i) explain what salinity is and describe how it varies from the <span class="hlt">ocean</span> to the river, (ii) explain what a mangrove is and describe adaptations mangroves have developed that allow them to live in saline or brackish water, and adjust to changing sea level, and (iii) develop a grade-appropriate poster on mangroves or salinity and one interactive activity that uses the poster to engage students in learning. These objectives are accomplished by field trips to the <span class="hlt">ocean</span> and mangrove swamp, where each participant learns how to measure salinity and identify mangrove species. The hands-on field component is followed by a poster development session where participants design, present, and share feedback on their posters that they will bring back to their classrooms. This experience allows schoolteachers to intimately explore their coastal ecosystems and gain new perspectives about their environment that they can take back to their students. The workshop was designed through a collaborative effort between Pacific Resources for Education and Learning (PREL) NSF Pacific <span class="hlt">Climate</span> Education Partnership, University of Washington professors and graduate students and undergraduate students, Kosrae Department of Education, Kosrae Island Resource Management Authority (KIRMA), Kosrae Island Conservation and Safety Organization (KCSO), and local Kosraean schoolteachers and administrators. The workshop was offered to elementary school teachers from 4 of 5 school districts in 2013, 2014, and 2015, led by University of Washington scientists and PREL. Local education officials and PREL staff will lead future workshops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC53E0940H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC53E0940H"><span>Connecting <span class="hlt">Ocean</span> Heat Transport Changes from the Midlatitudes to the Arctic <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hezel, P.; Nummelin, A.; Li, C.</p> <p>2017-12-01</p> <p>Under greenhouse warming, <span class="hlt">climate</span> <span class="hlt">models</span> simulate a weakening of the Atlantic Meridional Overturning Circulation and the associated <span class="hlt">ocean</span> heat transport at midlatitudes but an increase in the <span class="hlt">ocean</span> heat transport to the Arctic <span class="hlt">Ocean</span>. These opposing trends lead to what could appear to be a discrepancy in the reported <span class="hlt">ocean</span> contribution to Arctic amplification. This study clarifies how <span class="hlt">ocean</span> heat transport affects Arctic <span class="hlt">climate</span> under strong greenhouse warming using a set of the 21st century simulations performed within the Coupled <span class="hlt">Model</span> Intercomparison Project. The results suggest that a future reduction in subpolar <span class="hlt">ocean</span> heat loss enhances <span class="hlt">ocean</span> heat transport to the Arctic <span class="hlt">Ocean</span>, driving an increase in Arctic <span class="hlt">Ocean</span> heat content and contributing to the intermodel spread in Arctic amplification. The results caution against extrapolating the forced <span class="hlt">oceanic</span> signal from the midlatitudes to the Arctic.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BGeo...14.5675L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BGeo...14.5675L"><span><span class="hlt">Climate</span> engineering and the <span class="hlt">ocean</span>: effects on biogeochemistry and primary production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lauvset, Siv K.; Tjiputra, Jerry; Muri, Helene</p> <p>2017-12-01</p> <p>Here we use an Earth system <span class="hlt">model</span> with interactive biogeochemistry to project future <span class="hlt">ocean</span> biogeochemistry impacts from the large-scale deployment of three different radiation management (RM) <span class="hlt">climate</span> engineering (also known as geoengineering) methods: stratospheric aerosol injection (SAI), marine sky brightening (MSB), and cirrus cloud thinning (CCT). We apply RM such that the change in radiative forcing in the RCP8.5 emission scenario is reduced to the change in radiative forcing in the RCP4.5 scenario. The resulting global mean sea surface temperatures in the RM experiments are comparable to those in RCP4.5, but there are regional differences. The forcing from MSB, for example, is applied over the <span class="hlt">oceans</span>, so the cooling of the <span class="hlt">ocean</span> is in some regions stronger for this method of RM than for the others. Changes in <span class="hlt">ocean</span> net primary production (NPP) are much more variable, but SAI and MSB give a global decrease comparable to RCP4.5 (˜ 6 % in 2100 relative to 1971-2000), while CCT gives a much smaller global decrease of ˜ 3 %. Depending on the RM methods, the spatially inhomogeneous changes in <span class="hlt">ocean</span> NPP are related to the simulated spatial change in the NPP drivers (incoming radiation, temperature, availability of nutrients, and phytoplankton biomass) but mostly dominated by the circulation changes. In general, the SAI- and MSB-induced changes are largest in the low latitudes, while the CCT-induced changes tend to be the weakest of the three. The results of this work underscore the complexity of <span class="hlt">climate</span> impacts on NPP and highlight the fact that changes are driven by an integrated effect of multiple environmental drivers, which all change in different ways. These results stress the uncertain changes to <span class="hlt">ocean</span> productivity in the future and advocate caution at any deliberate attempt at large-scale perturbation of the Earth system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC13E..07D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC13E..07D"><span>U.S. 2013 National <span class="hlt">Climate</span> Assessment of <span class="hlt">Oceans</span> and Marine Resources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doney, S. C.; Rosenberg, A.</p> <p>2012-12-01</p> <p>We will discuss the key findings from the <span class="hlt">Oceans</span> and Marine Resources chapter of the U.S. 2013 National <span class="hlt">Climate</span> Assessment. As a nation, we depend on the <span class="hlt">ocean</span> for seafood, recreation and tourism, cultural heritage, transportation of goods, and increasingly, energy and other critical resources. The U.S. <span class="hlt">ocean</span> Exclusive Economic Zone extends 200 nautical miles seaward from the coast, spanning an area about 1.7 times the land area of the continental United States and encompassing waters along the U.S. east, west and Gulf coasts, around Alaska and Hawaii, and including the U.S. territories in the Pacific and Caribbean. This vast region is host to a rich diversity of marine plants and animals and a wide range of ecosystems from tropical coral reefs to sea-ice covered, polar waters in the Arctic. We will highlight the current state of knowledge on changing <span class="hlt">ocean</span> <span class="hlt">climate</span> conditions, such as warming, sea-ice retreat and <span class="hlt">ocean</span> acidification, and how these may be impacting valuable marine ecosystems and the array of resources and services we derive from the sea now and into the future. We will also touch on the interaction of <span class="hlt">climate</span> change impacts with other human factors including pollution and over-fishing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NPGeo..22..275R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NPGeo..22..275R"><span>Oscillations in a simple <span class="hlt">climate</span>-vegetation <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rombouts, J.; Ghil, M.</p> <p>2015-05-01</p> <p>We formulate and analyze a simple dynamical systems <span class="hlt">model</span> for <span class="hlt">climate</span>-vegetation interaction. The planet we consider consists of a large <span class="hlt">ocean</span> and a land surface on which vegetation can grow. The temperature affects vegetation growth on land and the amount of sea ice on the <span class="hlt">ocean</span>. Conversely, vegetation and sea ice change the albedo of the planet, which in turn changes its energy balance and hence the temperature evolution. Our highly idealized, conceptual <span class="hlt">model</span> is governed by two nonlinear, coupled ordinary differential equations, one for global temperature, the other for vegetation cover. The <span class="hlt">model</span> exhibits either bistability between a vegetated and a desert state or oscillatory behavior. The oscillations arise through a Hopf bifurcation off the vegetated state, when the death rate of vegetation is low enough. These oscillations are anharmonic and exhibit a sawtooth shape that is characteristic of relaxation oscillations, as well as suggestive of the sharp deglaciations of the Quaternary. Our <span class="hlt">model</span>'s behavior can be compared, on the one hand, with the bistability of even simpler, Daisyworld-style <span class="hlt">climate</span>-vegetation <span class="hlt">models</span>. On the other hand, it can be integrated into the hierarchy of <span class="hlt">models</span> trying to simulate and explain oscillatory behavior in the <span class="hlt">climate</span> system. Rigorous mathematical results are obtained that link the nature of the feedbacks with the nature and the stability of the solutions. The relevance of <span class="hlt">model</span> results to <span class="hlt">climate</span> variability on various timescales is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NPGD....2..145R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NPGD....2..145R"><span>Oscillations in a simple <span class="hlt">climate</span>-vegetation <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rombouts, J.; Ghil, M.</p> <p>2015-02-01</p> <p>We formulate and analyze a simple dynamical systems <span class="hlt">model</span> for <span class="hlt">climate</span>-vegetation interaction. The planet we consider consists of a large <span class="hlt">ocean</span> and a land surface on which vegetation can grow. The temperature affects vegetation growth on land and the amount of sea ice on the <span class="hlt">ocean</span>. Conversely, vegetation and sea ice change the albedo of the planet, which in turn changes its energy balance and hence the temperature evolution. Our highly idealized, conceptual <span class="hlt">model</span> is governed by two nonlinear, coupled ordinary differential equations, one for global temperature, the other for vegetation cover. The <span class="hlt">model</span> exhibits either bistability between a vegetated and a desert state or oscillatory behavior. The oscillations arise through a Hopf bifurcation off the vegetated state, when the death rate of vegetation is low enough. These oscillations are anharmonic and exhibit a sawtooth shape that is characteristic of relaxation oscillations, as well as suggestive of the sharp deglaciations of the Quaternary. Our <span class="hlt">model</span>'s behavior can be compared, on the one hand, with the bistability of even simpler, Daisyworld-style <span class="hlt">climate</span>-vegetation <span class="hlt">models</span>. On the other hand, it can be integrated into the hierarchy of <span class="hlt">models</span> trying to simulate and explain oscillatory behavior in the <span class="hlt">climate</span> system. Rigorous mathematical results are obtained that link the nature of the feedbacks with the nature and the stability of the solutions. The relevance of <span class="hlt">model</span> results to <span class="hlt">climate</span> variability on various time scales is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ESD.....7..559L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ESD.....7..559L"><span><span class="hlt">Climate</span> change increases riverine carbon outgassing, while export to the <span class="hlt">ocean</span> remains uncertain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Langerwisch, F.; Walz, A.; Rammig, A.; Tietjen, B.; Thonicke, K.; Cramer, W.</p> <p>2016-07-01</p> <p>Any regular interaction of land and river during flooding affects carbon pools within the terrestrial system, riverine carbon and carbon exported from the system. In the Amazon basin carbon fluxes are considerably influenced by annual flooding, during which terrigenous organic material is imported to the river. The Amazon basin therefore represents an excellent example of a tightly coupled terrestrial-riverine system. The processes of generation, conversion and transport of organic carbon in such a coupled terrigenous-riverine system strongly interact and are <span class="hlt">climate</span>-sensitive, yet their functioning is rarely considered in Earth system <span class="hlt">models</span> and their response to <span class="hlt">climate</span> change is still largely unknown. To quantify regional and global carbon budgets and <span class="hlt">climate</span> change effects on carbon pools and carbon fluxes, it is important to account for the coupling between the land, the river, the <span class="hlt">ocean</span> and the atmosphere. We developed the RIVerine Carbon <span class="hlt">Model</span> (RivCM), which is directly coupled to the well-established dynamic vegetation and hydrology <span class="hlt">model</span> LPJmL, in order to account for this large-scale coupling. We evaluate RivCM with observational data and show that some of the values are reproduced quite well by the <span class="hlt">model</span>, while we see large deviations for other variables. This is mainly caused by some simplifications we assumed. Our evaluation shows that it is possible to reproduce large-scale carbon transport across a river system but that this involves large uncertainties. Acknowledging these uncertainties, we estimate the potential changes in riverine carbon by applying RivCM for <span class="hlt">climate</span> forcing from five <span class="hlt">climate</span> <span class="hlt">models</span> and three CO2 emission scenarios (Special Report on Emissions Scenarios, SRES). We find that <span class="hlt">climate</span> change causes a doubling of riverine organic carbon in the southern and western basin while reducing it by 20 % in the eastern and northern parts. In contrast, the amount of riverine inorganic carbon shows a 2- to 3-fold increase in the entire basin</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP31F..04G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP31F..04G"><span><span class="hlt">Ocean</span> acidification in the Meso- vs. Cenozoic: lessons from <span class="hlt">modeling</span> about the geological expression of paleo-<span class="hlt">ocean</span> acidification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Greene, S. E.; Ridgwell, A.; Kirtland Turner, S.</p> <p>2015-12-01</p> <p>Rapid <span class="hlt">climatic</span> and biotic events putatively associated with <span class="hlt">ocean</span> acidification are scattered throughout the Meso-Cenozoic. Many of these rapid perturbations, variably referred to as hyperthermals (Paleogene) and <span class="hlt">oceanic</span> anoxic events or mass extinction events (Mesozoic), share a number of characteristic features, including some combination of negative carbon isotopic excursion, global warming, and a rise in atmospheric CO2 concentration. Comparisons between <span class="hlt">ocean</span> acidification events over the last ~250 Ma are, however, problematic because the types of marine geological archives and carbon reservoirs that can be interrogated are fundamentally different for early Mesozoic vs. late Mesozoic-Cenozoic events. Many Mesozoic events are known primarily or exclusively from geological outcrops of relatively shallow water deposits, whereas the more recent Paleogene hyperthermal events have been chiefly identified from deep sea records. In addition, these earlier events are superimposed on an <span class="hlt">ocean</span> with a fundamentally different carbonate buffering capacity, as calcifying plankton (which created the deep-sea carbonate sink) originate in the mid-Mesozoic. Here, we use both Earth system <span class="hlt">modeling</span> and reaction transport sediment <span class="hlt">modeling</span> to explore the ways in which comparable <span class="hlt">ocean</span> acidification-inducing <span class="hlt">climate</span> perturbations might manifest in the Mesozoic vs. the Cenozoic geological record. We examine the role of the deep-sea carbonate sink in the expression of <span class="hlt">ocean</span> acidification, as well as the spatial heterogeneity of surface <span class="hlt">ocean</span> pH and carbonate saturation state. These results critically inform interpretations of <span class="hlt">ocean</span> acidification prior to the mid-Mesozoic advent of calcifying plankton and expectations about the recording of these events in geological outcrop.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS31C1011M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS31C1011M"><span>Estimating the Numerical Diapycnal Mixing in the GO5.0 <span class="hlt">Ocean</span> <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Megann, A.; Nurser, G.</p> <p>2014-12-01</p> <p>Constant-depth (or "z-coordinate") <span class="hlt">ocean</span> <span class="hlt">models</span> such as MOM4 and NEMO have become the de facto workhorse in <span class="hlt">climate</span> applications, and have attained a mature stage in their development and are well understood. A generic shortcoming of this <span class="hlt">model</span> type, however, is a tendency for the advection scheme to produce unphysical numerical diapycnal mixing, which in some cases may exceed the explicitly parameterised mixing based on observed physical processes, and this is likely to have effects on the long-timescale evolution of the simulated <span class="hlt">climate</span> system. Despite this, few quantitative estimations have been made of the magnitude of the effective diapycnal diffusivity due to numerical mixing in these <span class="hlt">models</span>. GO5.0 is the latest <span class="hlt">ocean</span> <span class="hlt">model</span> configuration developed jointly by the UK Met Office and the National Oceanography Centre (Megann et al, 2014), and forms part of the GC1 and GC2 <span class="hlt">climate</span> <span class="hlt">models</span>. It uses version 3.4 of the NEMO <span class="hlt">model</span>, on the ORCA025 ¼° global tripolar grid. We describe various approaches to quantifying the numerical diapycnal mixing in this <span class="hlt">model</span>, and present results from analysis of the GO5.0 <span class="hlt">model</span> based on the isopycnal watermass analysis of Lee et al (2002) that indicate that numerical mixing does indeed form a significant component of the watermass transformation in the <span class="hlt">ocean</span> interior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPC44B2208R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPC44B2208R"><span>Constraints on <span class="hlt">Oceanic</span> Meridional Transport of Heat and Carbon from Combined <span class="hlt">Oceanic</span> and Atmospheric Measurements.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Resplandy, L.; Keeling, R. F.; Stephens, B. B.; Bent, J. D.; Jacobson, A. R.; Rödenbeck, C.; Khatiwala, S.</p> <p>2016-02-01</p> <p>The global <span class="hlt">ocean</span> transports heat northward. The magnitude of this asymmetry between the two hemispheres is a key factor of the <span class="hlt">climate</span> system through the displacement of tropical precipitation north of the equator and its influence on Arctic temperature and sea-ice extent. These asymmetric influences on heat are however not well constrained by observations or <span class="hlt">models</span>. We identify a robust link between the <span class="hlt">ocean</span> heat asymmetry and the large-scale distribution in atmospheric oxygen, using both atmospheric and <span class="hlt">oceanic</span> observations and a suite of <span class="hlt">models</span> (<span class="hlt">oceanic</span>, <span class="hlt">climate</span> and inverse). Novel aircraft observations from the pole-to-pole HIPPO campaign reveal that the <span class="hlt">ocean</span> northward heat transport necessary to explain the atmospheric oxygen distribution is in the upper range of previous estimates from hydrographic sections and atmospheric reanalyses. Finally, we evidence a strong link between the <span class="hlt">oceanic</span> transports of heat and natural carbon. This supports the existence of a strong southward transport of natural carbon at the global scale, a feature present at pre-industrial times and still underlying the anthropogenic signal today. We find that current <span class="hlt">climate</span> <span class="hlt">models</span> systematically underestimate these natural large-scale <span class="hlt">ocean</span> meridional transports of heat and carbon, which bears on future <span class="hlt">climate</span> projections, in particular concerning Arctic <span class="hlt">climate</span>, possible shifts in rainfall and carbon sinks partition between the land and the <span class="hlt">ocean</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.1041G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.1041G"><span>The new version of the Institute of Numerical Mathematics Sigma <span class="hlt">Ocean</span> <span class="hlt">Model</span> (INMSOM) for simulation of Global <span class="hlt">Ocean</span> circulation and its variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gusev, Anatoly; Fomin, Vladimir; Diansky, Nikolay; Korshenko, Evgeniya</p> <p>2017-04-01</p> <p>In this paper, we present the improved version of the <span class="hlt">ocean</span> general circulation sigma-<span class="hlt">model</span> developed in the Institute of Numerical Mathematics of the Russian Academy of Sciences (INM RAS). The previous version referred to as INMOM (Institute of Numerical Mathematics <span class="hlt">Ocean</span> <span class="hlt">Model</span>) is used as the <span class="hlt">oceanic</span> component of the IPCC <span class="hlt">climate</span> system <span class="hlt">model</span> INMCM (Institute of Numerical Mathematics <span class="hlt">Climate</span> <span class="hlt">Model</span> (Volodin et al 2010,2013). Besides, INMOM as the only sigma-<span class="hlt">model</span> was used for simulations according to CORE-II scenario (Danabasoglu et al. 2014,2016; Downes et al. 2015; Farneti et al. 2015). In general, INMOM results are comparable to ones of other OGCMs and were used for investigation of <span class="hlt">climatic</span> variations in the North Atlantic (Gusev and Diansky 2014). However, detailed analysis of some CORE-II INMOM results revealed some disadvantages of the INMOM leading to considerable errors in reproducing some <span class="hlt">ocean</span> characteristics. So, the mass transport in the Antarctic Circumpolar Current (ACC) was overestimated. As well, there were noticeable errors in reproducing thermohaline structure of the <span class="hlt">ocean</span>. After analysing the previous results, the new version of the OGCM was developed. It was decided to entitle is INMSOM (Institute of Numerical Mathematics Sigma <span class="hlt">Ocean</span> <span class="hlt">Model</span>). The new title allows one to distingwish the new <span class="hlt">model</span>, first, from its older version, and second, from another z-<span class="hlt">model</span> developed in the INM RAS and referred to as INMIO (Institute of Numerical Mathematics and Institute of Oceanology <span class="hlt">ocean</span> <span class="hlt">model</span>) (Ushakov et al. 2016). There were numerous modifications in the <span class="hlt">model</span>, some of them are as follows. 1) Formulation of the <span class="hlt">ocean</span> circulation problem in terms of full free surface with taking into account water amount variation. 2) Using tensor form of lateral viscosity operator invariant to rotation. 3) Using isopycnal diffusion including Gent-McWilliams mixing. 4) Using atmospheric forcing computation according to NCAR methodology (Large and Yeager 2009). 5</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032513','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032513"><span>The Southern <span class="hlt">Ocean</span> in the Coupled <span class="hlt">Model</span> Intercomparison Project phase 5</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meijers, A. J. S.</p> <p>2014-01-01</p> <p>The Southern <span class="hlt">Ocean</span> is an important part of the global <span class="hlt">climate</span> system, but its complex coupled nature makes both its present state and its response to projected future <span class="hlt">climate</span> forcing difficult to <span class="hlt">model</span>. Clear trends in wind, sea-ice extent and <span class="hlt">ocean</span> properties emerged from multi-<span class="hlt">model</span> intercomparison in the Coupled <span class="hlt">Model</span> Intercomparison Project phase 3 (CMIP3). Here, we review recent analyses of the historical and projected wind, sea ice, circulation and bulk properties of the Southern <span class="hlt">Ocean</span> in the updated Coupled <span class="hlt">Model</span> Intercomparison Project phase 5 (CMIP5) ensemble. Improvements to the <span class="hlt">models</span> include higher resolutions, more complex and better-tuned parametrizations of <span class="hlt">ocean</span> mixing, and improved biogeochemical cycles and atmospheric chemistry. CMIP5 largely reproduces the findings of CMIP3, but with smaller inter-<span class="hlt">model</span> spreads and biases. By the end of the twenty-first century, mid-latitude wind stresses increase and shift polewards. All water masses warm, and intermediate waters freshen, while bottom waters increase in salinity. Surface mixed layers shallow, warm and freshen, whereas sea ice decreases. The upper overturning circulation intensifies, whereas bottom water formation is reduced. Significant disagreement exists between <span class="hlt">models</span> for the response of the Antarctic Circumpolar Current strength, for reasons that are as yet unclear. PMID:24891395</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013713','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013713"><span>Comparative Analysis of Upper <span class="hlt">Ocean</span> Heat Content Variability from Ensemble Operational <span class="hlt">Ocean</span> Analyses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Xue, Yan; Balmaseda, Magdalena A.; Boyer, Tim; Ferry, Nicolas; Good, Simon; Ishikawa, Ichiro; Rienecker, Michele; Rosati, Tony; Yin, Yonghong; Kumar, Arun</p> <p>2012-01-01</p> <p>Upper <span class="hlt">ocean</span> heat content (HC) is one of the key indicators of <span class="hlt">climate</span> variability on many time-scales extending from seasonal to interannual to long-term <span class="hlt">climate</span> trends. For example, HC in the tropical Pacific provides information on thermocline anomalies that is critical for the longlead forecast skill of ENSO. Since HC variability is also associated with SST variability, a better understanding and monitoring of HC variability can help us understand and forecast SST variability associated with ENSO and other modes such as Indian <span class="hlt">Ocean</span> Dipole (IOD), Pacific Decadal Oscillation (PDO), Tropical Atlantic Variability (TAV) and Atlantic Multidecadal Oscillation (AMO). An accurate <span class="hlt">ocean</span> initialization of HC anomalies in coupled <span class="hlt">climate</span> <span class="hlt">models</span> could also contribute to skill in decadal <span class="hlt">climate</span> prediction. Errors, and/or uncertainties, in the estimation of HC variability can be affected by many factors including uncertainties in surface forcings, <span class="hlt">ocean</span> <span class="hlt">model</span> biases, and deficiencies in data assimilation schemes. Changes in observing systems can also leave an imprint on the estimated variability. The availability of multiple operational <span class="hlt">ocean</span> analyses (ORA) that are routinely produced by operational and research centers around the world provides an opportunity to assess uncertainties in HC analyses, to help identify gaps in observing systems as they impact the quality of ORAs and therefore <span class="hlt">climate</span> <span class="hlt">model</span> forecasts. A comparison of ORAs also gives an opportunity to identify deficiencies in data assimilation schemes, and can be used as a basis for development of real-time multi-<span class="hlt">model</span> ensemble HC monitoring products. The <span class="hlt">Ocean</span>Obs09 Conference called for an intercomparison of ORAs and use of ORAs for global <span class="hlt">ocean</span> monitoring. As a follow up, we intercompared HC variations from ten ORAs -- two objective analyses based on in-situ data only and eight <span class="hlt">model</span> analyses based on <span class="hlt">ocean</span> data assimilation systems. The mean, annual cycle, interannual variability and longterm trend of HC have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.1573J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.1573J"><span>Coupled ice sheet-<span class="hlt">ocean</span> <span class="hlt">modelling</span> to investigate <span class="hlt">ocean</span> driven melting of marine ice sheets in Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jong, Lenneke; Gladstone, Rupert; Galton-Fenzi, Ben</p> <p>2017-04-01</p> <p><span class="hlt">Ocean</span> induced melting below the ice shelves of marine ice sheets is a major source of uncertainty for predictions of ice mass loss and Antarctica's resultant contribution to future sea level rise. The floating ice shelves provide a buttressing force against the flow of ice across the grounding line into the <span class="hlt">ocean</span>. Thinning of these ice shelves due to an increase in melting reduces this force and can lead to an increase in the discharge of grounded ice. Fully coupled <span class="hlt">modelling</span> of ice sheet-<span class="hlt">ocean</span> interactions is key to improving understanding the influence of the Southern <span class="hlt">ocean</span> on the evolution of the Antarctic ice sheet, and to predicting its future behaviour under changing <span class="hlt">climate</span> conditions. Coupling of <span class="hlt">ocean</span> and ice sheet <span class="hlt">models</span> is needed to provide more realistic melt rates at the base of ice shelves and hence make better predictions of the behaviour of the grounding line and the shape of the ice-shelf cavity as the ice sheet evolves. The Framework for Ice Sheet - <span class="hlt">Ocean</span> Coupling (FISOC) has been developed to provide a flexible platform for performing coupled ice sheet - <span class="hlt">ocean</span> <span class="hlt">modelling</span> experiments. We present preliminary results using FISOC to couple the Regional <span class="hlt">Ocean</span> <span class="hlt">Modelling</span> System (ROMS) with Elmer/Ice in idealised experiments Marine Ice Sheet-<span class="hlt">Ocean</span> <span class="hlt">Model</span> Intercomparison Project (MISOMIP). These experiments use an idealised geometry motivated by that of Pine Island glacier and the adjacent Amundsen Sea in West Antarctica, a region which has shown shown signs of thinning ice and grounding line retreat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130010098','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130010098"><span>Tropical <span class="hlt">Ocean</span> Surface Energy Balance Variability: Linking Weather to <span class="hlt">Climate</span> Scales</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, J. Brent; Clayson, Carol Anne</p> <p>2013-01-01</p> <p>Radiative and turbulent surface exchanges of heat and moisture across the atmosphere-<span class="hlt">ocean</span> interface are fundamental components of the Earth s energy and water balance. Characterizing the spatiotemporal variability of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-<span class="hlt">ocean</span> feedbacks, and improving <span class="hlt">model</span> predictability. These fluxes are integral components to tropical <span class="hlt">ocean</span>-atmosphere variability; they can drive <span class="hlt">ocean</span> mixed layer variations and modify the atmospheric boundary layer properties including moist static stability, thereby influencing larger-scale tropical dynamics. Non-parametric cluster-based classification of atmospheric and <span class="hlt">ocean</span> surface properties has shown an ability to identify coherent weather regimes, each typically associated with similar properties and processes. Using satellite-based observational radiative and turbulent energy flux products, this study investigates the relationship between these weather states and surface energy processes within the context of tropical <span class="hlt">climate</span> variability. Investigations of surface energy variations accompanying intraseasonal and interannual tropical variability often use composite-based analyses of the mean quantities of interest. Here, a similar compositing technique is employed, but the focus is on the distribution of the heat and moisture fluxes within their weather regimes. Are the observed changes in surface energy components dominated by changes in the frequency of the weather regimes or through changes in the associated fluxes within those regimes? It is this question that the presented work intends to address. The distribution of the surface heat and moisture fluxes is evaluated for both normal and non-normal states. By examining both phases of the <span class="hlt">climatic</span> oscillations, the symmetry of energy and water cycle responses are considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70180967','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70180967"><span>Biological response to <span class="hlt">climate</span> change in the Arctic <span class="hlt">Ocean</span>: The view from the past</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cronin, Thomas M.; Cronin, Matthew A.</p> <p>2017-01-01</p> <p>The Arctic <span class="hlt">Ocean</span> is undergoing rapid <span class="hlt">climatic</span> changes including higher <span class="hlt">ocean</span> temperatures, reduced sea ice, glacier and Greenland Ice Sheet melting, greater marine productivity, and altered carbon cycling. Until recently, the relationship between <span class="hlt">climate</span> and Arctic biological systems was poorly known, but this has changed substantially as advances in paleoclimatology, micropaleontology, vertebrate paleontology, and molecular genetics show that Arctic ecosystem history reflects global and regional <span class="hlt">climatic</span> changes over all timescales and <span class="hlt">climate</span> states (103–107 years). Arctic <span class="hlt">climatic</span> extremes include 25°C hyperthermal periods during the Paleocene-Eocene (56–46 million years ago, Ma), Quaternary glacial periods when thick ice shelves and sea ice cover rendered the Arctic <span class="hlt">Ocean</span> nearly uninhabitable, seasonally sea-ice-free interglacials and abrupt <span class="hlt">climate</span> reversals. <span class="hlt">Climate</span>-driven biological impacts included large changes in species diversity, primary productivity, species’ geographic range shifts into and out of the Arctic, community restructuring, and possible hybridization, but evidence is not sufficient to determine whether or when major episodes of extinction occurred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CliPD...8.2819H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CliPD...8.2819H"><span><span class="hlt">Climate</span> and vegetation changes around the Atlantic <span class="hlt">Ocean</span> resulting from changes in the meridional overturning circulation during deglaciation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Handiani, D.; Paul, A.; Dupont, L.</p> <p>2012-07-01</p> <p>The Bølling-Allerød (BA, starting ~ 14.5 ka BP) is one of the most pronounced abrupt warming periods recorded in ice and pollen proxies. The leading explanation of the cause of this warming is a sudden increase in the rate of deepwater formation in the North Atlantic <span class="hlt">Ocean</span> and the resulting effect on the heat transport by the Atlantic Meridional Overturning Circulation (AMOC). In this study, we used the University of Victoria (UVic) Earth System-<span class="hlt">Climate</span> <span class="hlt">Model</span> (ESCM) to run simulations, in which a freshwater perturbation initiated a BA-like warming period. We found that under present <span class="hlt">climate</span> conditions, the AMOC intensified when freshwater was added to the Southern <span class="hlt">Ocean</span>. However, under Heinrich event 1 (HE1, ~ 16 ka BP) <span class="hlt">climate</span> conditions, the AMOC only intensified when freshwater was extracted from the North Atlantic <span class="hlt">Ocean</span>, possibly corresponding to an increase in evaporation or a decrease in precipitation in this region. The intensified AMOC led to a warming in the North Atlantic <span class="hlt">Ocean</span> and a cooling in the South Atlantic <span class="hlt">Ocean</span>, resembling the bipolar seesaw pattern typical of the last glacial period. In addition to the physical response, we also studied the simulated vegetation response around the Atlantic <span class="hlt">Ocean</span> region. Corresponding with the bipolar seesaw hypothesis, the rainbelt associated with the Intertropical Convergence Zone (ITCZ) shifted northward and affected the vegetation pattern in the tropics. The most sensitive vegetation area was found in tropical Africa, where grass cover increased and tree cover decreased under dry <span class="hlt">climate</span> conditions. An equal but opposite response to the collapse and recovery of the AMOC implied that the change in vegetation cover was transient and robust to an abrupt <span class="hlt">climate</span> change such as during the BA period, which is also supported by paleovegetation data. The results are in agreement with paleovegetation records from Western tropical Africa, which also show a reduction in forest cover during this time period. Further</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMGC51F1081J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMGC51F1081J"><span><span class="hlt">Modeling</span> seasonality of ice and <span class="hlt">ocean</span> carbon production in the Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, M.; Deal, C. M.; Ji, R.</p> <p>2011-12-01</p> <p>In the Arctic <span class="hlt">Ocean</span>, both phytoplankton and sea ice algae are important contributors to the primary production and the arctic food web. Copepod in the arctic regions have developed their feeding habit depending on the timing between the ice algal bloom and the subsequent phytoplankton bloom. A mismatch of the timing due to <span class="hlt">climate</span> changes could have dramatic consequences on the food web as shown by some regional observations. In this study, a global coupled ice-<span class="hlt">ocean</span>-ecosystem <span class="hlt">model</span> was used to assess the seasonality of the ice algal and phytoplankton blooms in the arctic. The ice-<span class="hlt">ocean</span> ecosystem modules are fully coupled in the physical <span class="hlt">model</span> POP-CICE (Parallel <span class="hlt">Ocean</span> Program- Los Alamos Sea Ice <span class="hlt">Model</span>). The <span class="hlt">model</span> results are compared with various observations. The <span class="hlt">modeled</span> ice and <span class="hlt">ocean</span> carbon production were analyzed by regions and their linkage to the physical environment changes (such as changes of ice concentration and water temperature, and light intensity etc.) between low- and high-ice years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ClDy...37.1929V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ClDy...37.1929V"><span>Global and regional <span class="hlt">ocean</span> carbon uptake and <span class="hlt">climate</span> change: sensitivity to a substantial mitigation scenario</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vichi, Marcello; Manzini, Elisa; Fogli, Pier Giuseppe; Alessandri, Andrea; Patara, Lavinia; Scoccimarro, Enrico; Masina, Simona; Navarra, Antonio</p> <p>2011-11-01</p> <p>Under future scenarios of business-as-usual emissions, the <span class="hlt">ocean</span> storage of anthropogenic carbon is anticipated to decrease because of <span class="hlt">ocean</span> chemistry constraints and positive feedbacks in the carbon-<span class="hlt">climate</span> dynamics, whereas it is still unknown how the <span class="hlt">oceanic</span> carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric "target" concentrations and assess the response of the <span class="hlt">ocean</span> carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System <span class="hlt">Model</span> that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century <span class="hlt">ocean</span> uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific <span class="hlt">Ocean</span> and to lower values in the Atlantic. With A1B, the major <span class="hlt">ocean</span> basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle <span class="hlt">models</span>, while at the regional level the response is contrasting. The <span class="hlt">model</span> indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The <span class="hlt">model</span> results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic <span class="hlt">oceans</span> is projected to be halved with respect to the current <span class="hlt">climate</span> under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005NCimC..28..173B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005NCimC..28..173B"><span>Cryosphere-hydrosphere interactions: numerical <span class="hlt">modeling</span> using the Regional <span class="hlt">Ocean</span> <span class="hlt">Modeling</span> System (ROMS) at different scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergamasco, A.; Budgell, W. P.; Carniel, S.; Sclavo, M.</p> <p>2005-03-01</p> <p>Conveyor belt circulation controls global <span class="hlt">climate</span> through heat and water fluxes with atmosphere and from tropical to polar regions and vice versa. This circulation, commonly referred to as thermohaline circulation (THC), seems to have millennium time scale and nowadays--a non-glacial period--appears to be as rather stable. However, concern is raised by the buildup of CO2 and other greenhouse gases in the atmosphere (IPCC, Third assessment report: <span class="hlt">Climate</span> Change 2001. A contribution of working group I, II and III to the Third Assessment Report of the Intergovernmental Panel on <span class="hlt">Climate</span> Change (Cambridge Univ. Press, UK) 2001, http://www.ipcc.ch) as these may affect the THC conveyor paths. Since it is widely recognized that dense-water formation sites act as primary sources in strengthening quasi-stable THC paths (Stommel H., Tellus131961224), in order to simulate properly the consequences of such scenarios a better understanding of these <span class="hlt">oceanic</span> processes is needed. To successfully <span class="hlt">model</span> these processes, air-sea-ice-integrated <span class="hlt">modelling</span> approaches are often required. Here we focus on two polar regions using the Regional <span class="hlt">Ocean</span> <span class="hlt">Modeling</span> System (ROMS). In the first region investigated, the North Atlantic-Arctic, where open-<span class="hlt">ocean</span> deep convection and open-sea ice formation and dispersion under the intense air-sea interactions are the major engines, we use a new version of the coupled hydrodynamic-ice ROMS <span class="hlt">model</span>. The second area belongs to the Antarctica region inside the Southern <span class="hlt">Ocean</span>, where brine rejections during ice formation inside shelf seas origin dense water that, flowing along the continental slope, overflow becoming eventually abyssal waters. Results show how nowadays integrated-<span class="hlt">modelling</span> tasks have become more and more feasible and effective; numerical simulations dealing with large computational domains or challenging different <span class="hlt">climate</span> scenarios can be run on multi-processors platforms and on systems like LINUX clusters, made of the same hardware as PCs, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1212924B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1212924B"><span>Spatial and temporal Teleconnections of Sea Surface Temperature and <span class="hlt">Ocean</span> Indices to regional <span class="hlt">Climate</span> Variations across Thailand - a Pathway to understanding the Impact of <span class="hlt">Climate</span> Change on Water Resources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bejranonda, Werapol; Koch, Manfred</p> <p>2010-05-01</p> <p>Thailand has a long coastline with the Pacific <span class="hlt">Ocean</span>, as part of the Gulf of Thailand, as well as with the Indian <span class="hlt">Ocean</span>, as part of the Andaman Sea. Because of this peculiar location, Thailand's local <span class="hlt">climate</span> and, in particular, its water resources are strongly influenced by the mix of tropical wet, tropical dry and tropical monsoon seasons. Because of the large seasonal and interannual variations and irregularities of these, mainly <span class="hlt">ocean</span>-driven weather patterns, particularly in recent times, large-scale water storage in huge river-fed reservoirs has a long tradition in Thailand, providing water for urban, industrial and agricultural use during long dry seasonal periods. These reservoirs which are located all over Thailand gather water primarily from monsoon-driven rainfall during the wet season which, usually, lasts from May to October. During the dry season, November to April, when the monsoon winds move northward, the air masses are drier in central and northern Thailand, with rain falling here only a few days in a month. Southern Thailand, on the other hand, which is constituted mostly by the isthmus between the two <span class="hlt">oceans</span>, stays even hot and humid during that time period. Because of this tropical <span class="hlt">climate</span> pattern, the surface water resources in most of Thailand strongly hinge on the monsoon movements which, in turn, depend themselves upon the thermal states of the Pacific and Indian <span class="hlt">Oceans</span>. Therefore, the understanding of the recent strong seasonal and interannual <span class="hlt">climate</span> variations with their detrimental effects on the availability of hydrological water resources in most parts of Thailand, must include the analysis of changes of various sea-state indices in the adjacent <span class="hlt">oceans</span> and of their possible teleconnections with regional <span class="hlt">climate</span> indices across this country. With the modern coupled atmospheric-<span class="hlt">ocean</span> <span class="hlt">models</span> being able to predict the variations of many <span class="hlt">ocean</span> indices over a period of several months, namely, those driven by El Nino- Southern Oscillations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911799N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911799N"><span>Sensitivity of the <span class="hlt">ocean</span> overturning circulation to wind and mixing: theoretical scalings and global <span class="hlt">ocean</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nikurashin, Maxim; Gunn, Andrew</p> <p>2017-04-01</p> <p>The meridional overturning circulation (MOC) is a planetary-scale <span class="hlt">oceanic</span> flow which is of direct importance to the <span class="hlt">climate</span> system: it transports heat meridionally and regulates the exchange of CO2 with the atmosphere. The MOC is forced by wind and heat and freshwater fluxes at the surface and turbulent mixing in the <span class="hlt">ocean</span> interior. A number of conceptual theories for the sensitivity of the MOC to changes in forcing have recently been developed and tested with idealized numerical <span class="hlt">models</span>. However, the skill of the simple conceptual theories to describe the MOC simulated with higher complexity global <span class="hlt">models</span> remains largely unknown. In this study, we present a systematic comparison of theoretical and <span class="hlt">modelled</span> sensitivity of the MOC and associated deep <span class="hlt">ocean</span> stratification to vertical mixing and southern hemisphere westerlies. The results show that theories that simplify the <span class="hlt">ocean</span> into a single-basin, zonally-symmetric box are generally in a good agreement with a realistic, global <span class="hlt">ocean</span> circulation <span class="hlt">model</span>. Some disagreement occurs in the abyssal <span class="hlt">ocean</span>, where complex bottom topography is not taken into account by simple theories. Distinct regimes, where the MOC has a different sensitivity to wind or mixing, as predicted by simple theories, are also clearly shown by the global <span class="hlt">ocean</span> <span class="hlt">model</span>. The sensitivity of the Indo-Pacific, Atlantic, and global basins is analysed separately to validate the conceptual understanding of the upper and lower overturning cells in the theory.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.1442Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.1442Z"><span>Dynamical downscaling of historical <span class="hlt">climate</span> over CORDEX East Asia domain: A comparison of regional <span class="hlt">ocean</span>-atmosphere coupled <span class="hlt">model</span> to stand-alone RCM simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zou, Liwei; Zhou, Tianjun; Peng, Dongdong</p> <p>2016-02-01</p> <p>The FROALS (flexible regional <span class="hlt">ocean</span>-atmosphere-land system) <span class="hlt">model</span>, a regional <span class="hlt">ocean</span>-atmosphere coupled <span class="hlt">model</span>, has been applied to the Coordinated Regional Downscaling Experiment (CORDEX) East Asia domain. Driven by historical simulations from a global <span class="hlt">climate</span> system <span class="hlt">model</span>, dynamical downscaling for the period from 1980 to 2005 has been conducted at a uniform horizontal resolution of 50 km. The impacts of regional air-sea couplings on the simulations of East Asian summer monsoon rainfall have been investigated, and comparisons have been made to corresponding simulations performed using a stand-alone regional <span class="hlt">climate</span> <span class="hlt">model</span> (RCM). The added value of the FROALS <span class="hlt">model</span> with respect to the driving global <span class="hlt">climate</span> <span class="hlt">model</span> was evident in terms of both climatology and the interannual variability of summer rainfall over East China by the contributions of both the high horizontal resolution and the reasonably simulated convergence of the moisture fluxes. Compared with the stand-alone RCM simulations, the spatial pattern of the simulated low-level monsoon flow over East Asia and the western North Pacific was improved in the FROALS <span class="hlt">model</span> due to its inclusion of regional air-sea coupling. The results indicated that the simulated sea surface temperature (SSTs) resulting from the regional air-sea coupling were lower than those derived directly from the driving global <span class="hlt">model</span> over the western North Pacific north of 15°N. These colder SSTs had both positive and negative effects. On the one hand, they strengthened the western Pacific subtropical high, which improved the simulation of the summer monsoon circulation over East Asia. On the other hand, the colder SSTs suppressed surface evaporation and favored weaker local interannual variability in the SST, which led to less summer rainfall and weaker interannual rainfall variability over the Korean Peninsula and Japan. Overall, the reference simulation performed using the FROALS <span class="hlt">model</span> is reasonable in terms of rainfall over the land area of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GMD.....6.1157L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GMD.....6.1157L"><span>Failure analysis of parameter-induced simulation crashes in <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lucas, D. D.; Klein, R.; Tannahill, J.; Ivanova, D.; Brandon, S.; Domyancic, D.; Zhang, Y.</p> <p>2013-08-01</p> <p>Simulations using IPCC (Intergovernmental Panel on <span class="hlt">Climate</span> Change)-class <span class="hlt">climate</span> <span class="hlt">models</span> are subject to fail or crash for a variety of reasons. Quantitative analysis of the failures can yield useful insights to better understand and improve the <span class="hlt">models</span>. During the course of uncertainty quantification (UQ) ensemble simulations to assess the effects of <span class="hlt">ocean</span> <span class="hlt">model</span> parameter uncertainties on <span class="hlt">climate</span> simulations, we experienced a series of simulation crashes within the Parallel <span class="hlt">Ocean</span> Program (POP2) component of the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CCSM4). About 8.5% of our CCSM4 simulations failed for numerical reasons at combinations of POP2 parameter values. We applied support vector machine (SVM) classification from machine learning to quantify and predict the probability of failure as a function of the values of 18 POP2 parameters. A committee of SVM classifiers readily predicted <span class="hlt">model</span> failures in an independent validation ensemble, as assessed by the area under the receiver operating characteristic (ROC) curve metric (AUC > 0.96). The causes of the simulation failures were determined through a global sensitivity analysis. Combinations of 8 parameters related to <span class="hlt">ocean</span> mixing and viscosity from three different POP2 parameterizations were the major sources of the failures. This information can be used to improve POP2 and CCSM4 by incorporating correlations across the relevant parameters. Our method can also be used to quantify, predict, and understand simulation crashes in other complex geoscientific <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70010244','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70010244"><span>Tertiary <span class="hlt">climatic</span> change in the marginal northeastern Pacific <span class="hlt">Ocean</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Addicott, W.O.</p> <p>1969-01-01</p> <p>Analysis of distributional patterns of shallow-water molluscan faunas of the middle latitudes of the marginal northeastern Pacific <span class="hlt">Ocean</span> discloses a sharp reversal during the Miocene of the progressive <span class="hlt">climatic</span> deterioration. A low point in the Tertiary cooling trend during the Oligocene was followed by <span class="hlt">climatic</span> warming that culminated during the middle Miocene, as illustrated by a series of zoogeographic profiles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17770857','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17770857"><span>Tertiary <span class="hlt">climatic</span> change in the marginal northeastern pacific <span class="hlt">ocean</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Addicott, W O</p> <p>1969-08-08</p> <p>Analysis of distributional patterns of shallow-water molluscan faunas of the middle latitudes of the marginal northeastern Pacific <span class="hlt">Ocean</span> discloses a sharp reversal during the Miocene of the progressive <span class="hlt">climatic</span> deterioration. A low point in the Tertiary cooling trend during the Oligocene was followed by <span class="hlt">climatic</span> warming that culminated during the middle Miocene, as illustrated by a series of zoogeographic profiles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMOS22A..08P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMOS22A..08P"><span>Revealing <span class="hlt">climate</span> modes in steric sea levels: lessons learned from satellite geodesy, objective analyses and <span class="hlt">ocean</span> reanalyses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pfeffer, J.; Tregoning, P.; Purcell, A. P.</p> <p>2017-12-01</p> <p>Due to increased greenhouse gases emissions, the <span class="hlt">oceans</span> are accumulating heat. In response to the <span class="hlt">ocean</span> circulation and atmospheric forcing, the heat is irregularly redistributed within the <span class="hlt">oceans</span>, causing sea level to rise at variable rates in space and time. These rates of steric expansion are extremely difficult to assess because of the sparsity of in-situ hydrographic observations available within the course of the 20th century. We compare here three methods to reconstruct the steric sea levels over the past 13, 25 and 58 years based on satellite geodesy, objective analyses and <span class="hlt">ocean</span> reanalyses. The interannual to decadal variability of each dataset is explored with a <span class="hlt">model</span> merging six <span class="hlt">climate</span> indices representative of the natural variability of the <span class="hlt">ocean</span> and <span class="hlt">climate</span> system. Consistent regional patterns are identified for the Pacific Decadal Oscillation (PDO) and El Niño Southern Oscillation (ENSO) in all datasets at all timescales. Despite the short time coverage (13 years), the combination of satellite geodetic data (altimetry and GRACE) also reveals significant steric responses to the North Pacific Gyre Oscillation (NPGO), Indian Dipole (IOD) and Indian <span class="hlt">ocean</span> basinwide (IOBM) mode. The richer information content in the <span class="hlt">ocean</span> reanalyses allows us to recover the regional fingerprints of the PDO, ENSO, NPGO, IOD and IOBM, but also of the Atlantic Multidecadal Oscillation (AMO) acting over longer time scales (40 to 60 years). Therefore, <span class="hlt">ocean</span> reanalyses, coupled with <span class="hlt">climate</span> mode analyses, constitute innovative and promising tools to investigate the mechanisms triggering the variability of sea level rise over the past decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1433384','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1433384"><span>Final Technical Report for Collaborative Research: Developing and Implementing <span class="hlt">Ocean</span>-Atmosphere Reanalyses for <span class="hlt">Climate</span> Applications (OARCA)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Compo, Gilbert P</p> <p></p> <p>As an important step toward a coupled data assimilation system for generating reanalysis fields needed to assess <span class="hlt">climate</span> <span class="hlt">model</span> projections, the <span class="hlt">Ocean</span> Atmosphere Coupled Reanalysis for <span class="hlt">Climate</span> Applications (OARCA) project assesses and improves the longest reanalyses currently available of the atmosphere and <span class="hlt">ocean</span>: the 20th Century Reanalysis Project (20CR) and the Simple <span class="hlt">Ocean</span> Data Assimilation with sparse observational input (SODAsi) system, respectively. In this project, we make off-line but coordinated improvements in the 20CR and SODAsi datasets, with improvements in one feeding into improvements of the other through an iterative generation of new versions. These datasets now span from themore » 19th to 21st centuries. We then study the extreme weather and variability from days to decades of the resulting datasets. A total of 24 publications have been produced in this project.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70180165','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70180165"><span>Surface temperatures of the Mid-Pliocene North Atlantic <span class="hlt">Ocean</span>: Implications for future <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dowsett, Harry J.; Chandler, Mark A.; Robinson, Marci M.</p> <p>2009-01-01</p> <p>The Mid-Pliocene is the most recent interval in the Earth's history to have experienced warming of the magnitude predicted for the second half of the twenty-first century and is, therefore, a possible analogue for future <span class="hlt">climate</span> conditions. With continents basically in their current positions and atmospheric CO2 similar to early twenty-first century values, the cause of Mid-Pliocene warmth remains elusive. Understanding the behaviour of the North Atlantic <span class="hlt">Ocean</span> during the Mid-Pliocene is integral to evaluating future <span class="hlt">climate</span> scenarios owing to its role in deep water formation and its sensitivity to <span class="hlt">climate</span> change. Under the framework of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) sea surface reconstruction, we synthesize Mid-Pliocene North Atlantic studies by PRISM members and others, describing each region of the North Atlantic in terms of palaeoceanography. We then relate Mid-Pliocene sea surface conditions to expectations of future warming. The results of the data and <span class="hlt">climate</span> <span class="hlt">model</span> comparisons suggest that the North Atlantic is more sensitive to <span class="hlt">climate</span> change than is suggested by <span class="hlt">climate</span> <span class="hlt">model</span> simulations, raising the concern that estimates of future <span class="hlt">climate</span> change are conservative.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22493225','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22493225"><span>Role of the Bering Strait on the hysteresis of the <span class="hlt">ocean</span> conveyor belt circulation and glacial <span class="hlt">climate</span> stability.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Aixue; Meehl, Gerald A; Han, Weiqing; Timmermann, Axel; Otto-Bliesner, Bette; Liu, Zhengyu; Washington, Warren M; Large, William; Abe-Ouchi, Ayako; Kimoto, Masahide; Lambeck, Kurt; Wu, Bingyi</p> <p>2012-04-24</p> <p>Abrupt <span class="hlt">climate</span> transitions, known as Dansgaard-Oeschger and Heinrich events, occurred frequently during the last glacial period, specifically from 80-11 thousand years before present, but were nearly absent during interglacial periods and the early stages of glacial periods, when major ice-sheets were still forming. Here we show, with a fully coupled state-of-the-art <span class="hlt">climate</span> <span class="hlt">model</span>, that closing the Bering Strait and preventing its throughflow between the Pacific and Arctic <span class="hlt">Oceans</span> during the glacial period can lead to the emergence of stronger hysteresis behavior of the <span class="hlt">ocean</span> conveyor belt circulation to create conditions that are conducive to triggering abrupt <span class="hlt">climate</span> transitions. Hence, it is argued that even for greenhouse warming, abrupt <span class="hlt">climate</span> transitions similar to those in the last glacial time are unlikely to occur as the Bering Strait remains open.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP43B1571R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP43B1571R"><span>Eocene <span class="hlt">climate</span> and Arctic paleobathymetry: A tectonic sensitivity study using GISS <span class="hlt">ModelE-R</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberts, C. D.; Legrande, A. N.; Tripati, A. K.</p> <p>2009-12-01</p> <p>The early Paleogene (65-45 million years ago, Ma) was a ‘greenhouse’ interval with global temperatures warmer than any other time in the last 65 Ma. This period was characterized by high levels of CO2, warm high-latitudes, warm surface-and-deep <span class="hlt">oceans</span>, and an intensified hydrological cycle. Sediments from the Arctic suggest that the Eocene surface Arctic <span class="hlt">Ocean</span> was warm, brackish, and episodically enabled the freshwater fern Azolla to bloom. The precise mechanisms responsible for the development of these conditions remain uncertain. We present equilibrium <span class="hlt">climate</span> conditions derived from a fully-coupled, water-isotope enabled, general circulation <span class="hlt">model</span> (GISS <span class="hlt">ModelE-R</span>) configured for the early Eocene. We also present <span class="hlt">model</span>-data comparison plots for key <span class="hlt">climatic</span> variables (SST and δ18O) and analyses of the leading modes of variability in the tropical Pacific and North Atlantic regions. Our tectonic sensitivity study indicates that Northern Hemisphere <span class="hlt">climate</span> would have been very sensitive to the degree of <span class="hlt">oceanic</span> exchange through the seaways connecting the Arctic to the Atlantic and Tethys. By restricting these seaways, we simulate freshening of the surface Arctic <span class="hlt">Ocean</span> to ~6 psu and warming of sea-surface temperatures by 2°C in the North Atlantic and 5-10°C in the Labrador Sea. Our results may help explain the occurrence of low-salinity tolerant taxa in the Arctic <span class="hlt">Ocean</span> during the Eocene and provide a mechanism for enhanced warmth in the north western Atlantic. We also suggest that the formation of a volcanic land-bridge between Greenland and Europe could have caused increased <span class="hlt">ocean</span> convection and warming of intermediate waters in the Atlantic. If true, this result is consistent with the theory that bathymetry changes may have caused thermal destabilisation of methane clathrates in the Atlantic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010319','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010319"><span>Fast Atmosphere-<span class="hlt">Ocean</span> <span class="hlt">Model</span> Runs with Large Changes in CO2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, Gary L.; Lacis, Andrew A.; Rind, David H.; Colose, Christopher; Opstbaum, Roger F.</p> <p>2013-01-01</p> <p>How does <span class="hlt">climate</span> sensitivity vary with the magnitude of <span class="hlt">climate</span> forcing? This question was investigated with the use of a modified coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span>, whose stability was improved so that the <span class="hlt">model</span> would accommodate large radiative forcings yet be fast enough to reach rapid equilibrium. Experiments were performed in which atmospheric CO2 was multiplied by powers of 2, from 1/64 to 256 times the 1950 value. From 8 to 32 times, the 1950 CO2, <span class="hlt">climate</span> sensitivity for doubling CO2 reaches 8 C due to increases in water vapor absorption and cloud top height and to reductions in low level cloud cover. As CO2 amount increases further, sensitivity drops as cloud cover and planetary albedo stabilize. No water vapor-induced runaway greenhouse caused by increased CO2 was found for the range of CO2 examined. With CO2 at or below 1/8 of the 1950 value, runaway sea ice does occur as the planet cascades to a snowball Earth <span class="hlt">climate</span> with fully ice covered <span class="hlt">oceans</span> and global mean surface temperatures near 30 C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29211734','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29211734"><span>Seafarer citizen scientist <span class="hlt">ocean</span> transparency data as a resource for phytoplankton and <span class="hlt">climate</span> research.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seafarers, Secchi Disk; Lavender, Samantha; Beaugrand, Gregory; Outram, Nicholas; Barlow, Nigel; Crotty, David; Evans, Jake; Kirby, Richard</p> <p>2017-01-01</p> <p>The <span class="hlt">oceans</span>' phytoplankton that underpin the marine food chain appear to be changing in abundance due to global <span class="hlt">climate</span> change. Here, we compare the first four years of data from a citizen science <span class="hlt">ocean</span> transparency study, conducted by seafarers using home-made Secchi Disks and a free Smartphone application called Secchi, with contemporaneous satellite <span class="hlt">ocean</span> colour measurements. Our results show seafarers collect useful Secchi Disk measurements of <span class="hlt">ocean</span> transparency that could help future assessments of <span class="hlt">climate</span>-induced changes in the phytoplankton when used to extend historical Secchi Disk data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24006803','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24006803"><span>Effect of <span class="hlt">climate-ocean</span> changes on the abundance of Pacific saury.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gong, Yeong; Suh, Young Sang</p> <p>2013-01-01</p> <p>Effects of <span class="hlt">ocean</span> <span class="hlt">climate</span> changes on the population structure and abundance of Pacific saury (Cololabis sira) were investigated on the basis of <span class="hlt">climate</span> indices, sea surface temperature (SST) anomalies, catch and body size information from the Tsushima Warm Current (TWC) region (Yellow Sea, East China Sea and East/Japan Sea) during the period 1950-2010. It is suggested that <span class="hlt">oceanic</span> regime shifts in the early 1970s, late 1980s and late 1990s occurred in the TWC region in winter, but the regime shifts in the mid-1970s and in the late 1980s were not evident in the spring SST anomaly series. The abundance and body size of Pacific saury fluctuated in association with the winter <span class="hlt">oceanic</span> changes in the TWC region. The catch rates and abundance of large size saury were far bellow average during their northward migrations in the TWC region in the years with abnormally cool winters (e.g., 1963, 1970, 1977, 1981-1989 and 2006) and above average in the years with warm winters. These patterns demonstrate decadal-scale variations together with large inter-annual fluctuations in the structure and abundance of Pacific saury in association with the <span class="hlt">climatic-oceanic</span> changes. These results, along with an alternation of dominant pelagic fish species, indicate the status of the saury population in the TWC region is in good condition, similar to that in the Kuroshio-Oyashio Current (KOC) region during the warm regime after the late 1980s <span class="hlt">climate</span> regime shift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......347M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......347M"><span>Investigations of the <span class="hlt">Climate</span> System Response to <span class="hlt">Climate</span> Engineering in a Hierarchy of <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCusker, Kelly E.</p> <p></p> <p>Global warming due to anthropogenic emissions of greenhouse gases is causing negative impacts on diverse ecological and human systems around the globe, and these impacts are projected to worsen as <span class="hlt">climate</span> continues to warm. In the absence of meaningful greenhouse gas emissions reductions, new strategies have been proposed to engineer the <span class="hlt">climate</span>, with the aim of preventing further warming and avoiding associated <span class="hlt">climate</span> impacts. We investigate one such strategy here, falling under the umbrella of `solar radiation management', in which sulfate aerosols are injected into the stratosphere. We use a global <span class="hlt">climate</span> <span class="hlt">model</span> with a coupled mixed-layer depth <span class="hlt">ocean</span> and with a fully-coupled <span class="hlt">ocean</span> general circulation <span class="hlt">model</span> to simulate the stabilization of <span class="hlt">climate</span> by balancing increasing carbon dioxide with increasing stratospheric sulfate concentrations. We evaluate whether or not severe <span class="hlt">climate</span> impacts, such as melting Arctic sea ice, tropical crop failure, or destabilization of the West Antarctic ice sheet, could be avoided. We find that while tropical <span class="hlt">climate</span> emergencies might be avoided by use of stratospheric aerosol injections, avoiding polar emergencies cannot be guaranteed due to large residual <span class="hlt">climate</span> changes in those regions, which are in part due to residual atmospheric circulation anomalies. We also find that the inclusion of a fully-coupled <span class="hlt">ocean</span> is important for determining the regional <span class="hlt">climate</span> response because of its dynamical feedbacks. The efficacy of stratospheric sulfate aerosol injections, and solar radiation management more generally, depends on its ability to be maintained indefinitely, without interruption from a variety of possible sources, such as technological failure, a breakdown in global cooperation, lack of funding, or negative unintended consequences. We next consider the scenario in which stratospheric sulfate injections are abruptly terminated after a multi- decadal period of implementation while greenhouse gas emissions have continued unabated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19980032172&hterms=climate+change+evidence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dclimate%2Bchange%2Bevidence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19980032172&hterms=climate+change+evidence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dclimate%2Bchange%2Bevidence"><span>The Status of Mars <span class="hlt">Climate</span> Change <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Haberle, Robert M.</p> <p>1997-01-01</p> <p>Researchers have reviewed the evidence that the <span class="hlt">climate</span> of Mars has changed throughout its history. In this paper, the discussion focuses on where we stand in terms of <span class="hlt">modeling</span> these <span class="hlt">climate</span> changes. For convenience, three distinct types of <span class="hlt">climate</span> regimes are considered: very early in the planet's history (more than 3.5 Ga), when warm wet conditions are thought to have prevailed; the bulk of the planet's history (3.5-1 Ga), during which episodic <span class="hlt">ocean</span> formation has been suggested; and relatively recently in the planet's history (less than 1 Ga), when orbitally induced <span class="hlt">climate</span> change is thought to have occurred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/381000-climatic-impact-amazon-deforestation-mechanistic-model-study','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/381000-climatic-impact-amazon-deforestation-mechanistic-model-study"><span><span class="hlt">Climatic</span> impact of Amazon deforestation - a mechanistic <span class="hlt">model</span> study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ning Zeng; Dickinson, R.E.; Xubin Zeng</p> <p>1996-04-01</p> <p>Recent general circulation <span class="hlt">model</span> (GCM) experiments suggest a drastic change in the regional <span class="hlt">climate</span>, especially the hydrological cycle, after hypothesized Amazon basinwide deforestation. To facilitate the theoretical understanding os such a change, we develop an intermediate-level <span class="hlt">model</span> for tropical climatology, including atmosphere-land-<span class="hlt">ocean</span> interaction. The <span class="hlt">model</span> consists of linearized steady-state primitive equations with simplified thermodynamics. A simple hydrological cycle is also included. Special attention has been paid to land-surface processes. It generally better simulates tropical climatology and the ENSO anomaly than do many of the previous simple <span class="hlt">models</span>. The <span class="hlt">climatic</span> impact of Amazon deforestation is studied in the context of thismore » <span class="hlt">model</span>. <span class="hlt">Model</span> results show a much weakened Atlantic Walker-Hadley circulation as a result of the existence of a strong positive feedback loop in the atmospheric circulation system and the hydrological cycle. The regional <span class="hlt">climate</span> is highly sensitive to albedo change and sensitive to evapotranspiration change. The pure dynamical effect of surface roughness length on convergence is small, but the surface flow anomaly displays intriguing features. Analysis of the thermodynamic equation reveals that the balance between convective heating, adiabatic cooling, and radiation largely determines the deforestation response. Studies of the consequences of hypothetical continuous deforestation suggest that the replacement of forest by desert may be able to sustain a dry <span class="hlt">climate</span>. Scaling analysis motivated by our <span class="hlt">modeling</span> efforts also helps to interpret the common results of many GCM simulations. When a simple mixed-layer <span class="hlt">ocean</span> <span class="hlt">model</span> is coupled with the atmospheric <span class="hlt">model</span>, the results suggest a 1{degrees}C decrease in SST gradient across the equatorial Atlantic <span class="hlt">Ocean</span> in response to Amazon deforestation. The magnitude depends on the coupling strength. 66 refs., 16 figs., 4 tabs.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611457M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611457M"><span>Estimating the numerical diapycnal mixing in the GO5.0 <span class="hlt">ocean</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Megann, Alex; Nurser, George</p> <p>2014-05-01</p> <p>Constant-depth (or "z-coordinate") <span class="hlt">ocean</span> <span class="hlt">models</span> such as MOM and NEMO have become the de facto workhorse in <span class="hlt">climate</span> applications, and have attained a mature stage in their development and are well understood. A generic shortcoming of this <span class="hlt">model</span> type, however, is a tendency for the advection scheme to produce unphysical numerical diapycnal mixing, which in some cases may exceed the explicitly parameterised mixing based on observed physical processes (e.g. Hofmann and Maqueda, 2006), and this is likely to have effects on the long-timescale evolution of the simulated <span class="hlt">climate</span> system. Despite this, few quantitative estimations have been made of the typical magnitude of the effective diapycnal diffusivity due to numerical mixing in these <span class="hlt">models</span>. GO5.0 is the latest <span class="hlt">ocean</span> <span class="hlt">model</span> configuration developed jointly by the UK Met Office and the National Oceanography Centre (Megann et al, 2013). It uses version 3.4 of the NEMO <span class="hlt">model</span>, on the ORCA025 global tripolar grid. Two approaches to quantifying the numerical diapycnal mixing in this <span class="hlt">model</span> are described: the first is based on the isopycnal watermass analysis of Lee et al (2002), while the second uses a passive tracer to diagnose mixing across density surfaces. Results from these two methods will be compared and contrasted. Hofmann, M. and Maqueda, M. A. M., 2006. Performance of a second-order moments advection scheme in an <span class="hlt">ocean</span> general circulation <span class="hlt">model</span>. JGR-<span class="hlt">Oceans</span>, 111(C5). Lee, M.-M., Coward, A.C., Nurser, A.G., 2002. Spurious diapycnal mixing of deep waters in an eddy-permitting global <span class="hlt">ocean</span> <span class="hlt">model</span>. JPO 32, 1522-1535 Megann, A., Storkey, D., Aksenov, Y., Alderson, S., Calvert, D., Graham, T., Hyder, P., Siddorn, J., and Sinha, B., 2013: GO5.0: The joint NERC-Met Office NEMO global <span class="hlt">ocean</span> <span class="hlt">model</span> for use in coupled and forced applications, Geosci. <span class="hlt">Model</span> Dev. Discuss., 6, 5747-5799,.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP23E..08I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP23E..08I"><span>The effect of sudden ice sheet melt on <span class="hlt">ocean</span> circulation and surface <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivanovic, R. F.; Gregoire, L. J.; Wickert, A. D.; Valdes, P. J.; Burke, A.</p> <p>2017-12-01</p> <p>Collapse of ice sheets can cause significant sea-level rise and widespread <span class="hlt">climate</span> change. Around 14.6 thousand years ago, global mean sea level rose by 15 m in less than 350 years during an event known as Meltwater Pulse 1a. Ice sheet <span class="hlt">modelling</span> and sea-level fingerprinting has suggested that approximately half of this 50 mm yr-1 sea level rise may have come from a North American ice Saddle Collapse that drained into the Arctic and Atlantic <span class="hlt">Oceans</span>. However, dating uncertainties make it difficult to determine the sequence of events and their drivers, leaving many fundamental questions. For example, was melting from the northern ice sheets responsible for the Older-Dryas or other global-scale cooling events, or did a contribution from Antarctica counteract the <span class="hlt">climatic</span> effects? What was the role of the abrupt Bølling Warming? And how were all these signals linked to changes in Atlantic <span class="hlt">Ocean</span> overturning circulation?To address these questions, we examined the effect of the North American ice Saddle Collapse using a high resolution network drainage <span class="hlt">model</span> coupled to an atmosphere-<span class="hlt">ocean</span>-vegetation General Circulation <span class="hlt">Model</span>. Here, we present the quantitative routing estimates of the consequent meltwater discharge and its impact on <span class="hlt">climate</span>. We also tested a suite of more idealised meltwater forcing scenarios to examine the global influence of Arctic versus Antarctic ice melt. The results show that 50% of the Saddle Collapse meltwater pulse was routed via the Mackenzie River into the Arctic <span class="hlt">Ocean</span>, and 50% was discharged directly into the Atlantic/Gulf of Mexico. This meltwater flux, equivalent to a total of 7.3 m of sea-level rise, caused a strong (6 Sv) weakening of Atlantic Meridional Overturning Circulation (AMOC) and widespread Northern Hemisphere cooling of 1-5 °C. The greatest cooling is in the Arctic (5-10 °C in the winter), but there is also significant winter warming over eastern North America (1-3 °C). We propose that this robust submillennial mechanism was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JAMES..10..165L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JAMES..10..165L"><span>Tropical Cyclone Activity in the High-Resolution Community Earth System <span class="hlt">Model</span> and the Impact of <span class="hlt">Ocean</span> Coupling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Hui; Sriver, Ryan L.</p> <p>2018-01-01</p> <p>High-resolution Atmosphere General Circulation <span class="hlt">Models</span> (AGCMs) are capable of directly simulating realistic tropical cyclone (TC) statistics, providing a promising approach for TC-<span class="hlt">climate</span> studies. Active air-sea coupling in a coupled <span class="hlt">model</span> framework is essential to capturing TC-<span class="hlt">ocean</span> interactions, which can influence TC-<span class="hlt">climate</span> connections on interannual to decadal time scales. Here we investigate how the choices of <span class="hlt">ocean</span> coupling can affect the directly simulated TCs using high-resolution configurations of the Community Earth System <span class="hlt">Model</span> (CESM). We performed a suite of high-resolution, multidecadal, global-scale CESM simulations in which the atmosphere (˜0.25° grid spacing) is configured with three different levels of <span class="hlt">ocean</span> coupling: prescribed climatological sea surface temperature (SST) (ATM), mixed layer <span class="hlt">ocean</span> (SLAB), and dynamic <span class="hlt">ocean</span> (CPL). We find that different levels of <span class="hlt">ocean</span> coupling can influence simulated TC frequency, geographical distributions, and storm intensity. ATM simulates more storms and higher overall storm intensity than the coupled simulations. It also simulates higher TC track density over the eastern Pacific and the North Atlantic, while TC tracks are relatively sparse within CPL and SLAB for these regions. Storm intensification and the maximum wind speed are sensitive to the representations of local surface flux feedbacks in different coupling configurations. Key differences in storm number and distribution can be attributed to variations in the <span class="hlt">modeled</span> large-scale <span class="hlt">climate</span> mean state and variability that arise from the combined effect of intrinsic <span class="hlt">model</span> biases and air-sea interactions. Results help to improve our understanding about the representation of TCs in high-resolution coupled Earth system <span class="hlt">models</span>, with important implications for TC-<span class="hlt">climate</span> applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4299185','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4299185"><span><span class="hlt">Climate</span> change decouples <span class="hlt">oceanic</span> primary and export productivity and organic carbon burial</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lopes, Cristina; Kucera, Michal; Mix, Alan C.</p> <p>2015-01-01</p> <p>Understanding responses of <span class="hlt">oceanic</span> primary productivity, carbon export, and burial to <span class="hlt">climate</span> change is essential for <span class="hlt">model</span>-based projection of biological feedbacks in a high-CO2 world. Here we compare estimates of productivity based on the composition of fossil diatom floras with organic carbon burial off Oregon in the Northeast Pacific across a large <span class="hlt">climatic</span> transition at the last glacial termination. Although estimated primary productivity was highest during the Last Glacial Maximum, carbon burial was lowest, reflecting reduced preservation linked to low sedimentation rates. A diatom size index further points to a glacial decrease (and deglacial increase) in the fraction of fixed carbon that was exported, inferred to reflect expansion, and contraction, of subpolar ecosystems that today favor smaller plankton. Thus, in contrast to <span class="hlt">models</span> that link remineralization of carbon to temperature, in the Northeast Pacific, we find dominant ecosystem and sea floor control such that intervals of warming <span class="hlt">climate</span> had more efficient carbon export and higher carbon burial despite falling primary productivity. PMID:25453073</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22270708','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22270708"><span>Integrated <span class="hlt">ocean</span> management as a strategy to meet rapid <span class="hlt">climate</span> change: the Norwegian case.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hoel, Alf Håkon; Olsen, Erik</p> <p>2012-02-01</p> <p>The prospects of rapid <span class="hlt">climate</span> change and the potential existence of tipping points in marine ecosystems where nonlinear change may result from them being overstepped, raises the question of strategies for coping with ecosystem change. There is broad agreement that the combined forces of <span class="hlt">climate</span> change, pollution and increasing economic activities necessitates more comprehensive approaches to <span class="hlt">oceans</span> management, centering on the concept of ecosystem-based <span class="hlt">oceans</span> management. This article addresses the Norwegian experience in introducing integrated, ecosystem-based <span class="hlt">oceans</span> management, emphasizing how <span class="hlt">climate</span> change, seen as a major long-term driver of change in ecosystems, is addressed in management plans. Understanding the direct effects of <span class="hlt">climate</span> variability and change on ecosystems and indirect effects on human activities is essential for adaptive planning to be useful in the long-term management of the marine environment.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSED24B1670M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSED24B1670M"><span>A <span class="hlt">Model</span> for Local Experiential Learning: Teacher Workshop on Mangroves, <span class="hlt">Oceans</span> & <span class="hlt">Climate</span> in Kosrae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maloney, A. E.; Sachs, J. P.; Barros, C.; Low, M.</p> <p>2016-02-01</p> <p>A curriculum for an intensive one-day workshop about mangroves, <span class="hlt">oceans</span>, and <span class="hlt">climate</span> has been developed for school teachers in the Federated States of Micronesia. The goals of the workshop are for teachers/attendees to be able to (i) explain what salinity is and describe how it varies from the <span class="hlt">ocean</span> to the river, (ii) explain what a mangrove is and describe adaptations mangroves have developed that allow them to live in saline or brackish water and adjust to changing sea level, and (iii) develop a grade-appropriate poster on mangroves or salinity and one interactive activity that uses the poster to engage students in learning. These objectives are accomplished by field trips to the <span class="hlt">ocean</span> and mangrove swamp, where each participant learns how to measure salinity and identify mangrove species. The hands-on field component is followed by a poster development session where participants design, present, and share feedback on their posters that they will bring back to their classrooms. This experience allows schoolteachers to intimately explore their coastal ecosystems and gain new perspectives about their environment that they can take back to their students. The workshop was designed through a collaborative effort between Pacific Resources for Education and Learning (PREL) NSF Pacific <span class="hlt">Climate</span> Education Partnership, University of Washington professors, graduate students and undergraduate students, Kosrae Department of Education, Kosrae Island Resource Management Authority (KIRMA), Kosrae Island Conservation and Safety Organization (KCSO), and local Kosraean schoolteachers and administrators. The workshop was offered to elementary school teachers from 4 of 5 school districts in 2013, 2014, and 2015, led by University of Washington scientists and PREL. Local education officials and PREL staff will lead future workshops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ClDy...39.1021P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ClDy...39.1021P"><span>Decadal-timescale changes of the Atlantic overturning circulation and <span class="hlt">climate</span> in a coupled <span class="hlt">climate</span> <span class="hlt">model</span> with a hybrid-coordinate <span class="hlt">ocean</span> component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Persechino, A.; Marsh, R.; Sinha, B.; Megann, A. P.; Blaker, A. T.; New, A. L.</p> <p>2012-08-01</p> <p>A wide range of statistical tools is used to investigate the decadal variability of the Atlantic Meridional Overturning Circulation (AMOC) and associated key variables in a <span class="hlt">climate</span> <span class="hlt">model</span> (CHIME, Coupled Hadley-Isopycnic <span class="hlt">Model</span> Experiment), which features a novel <span class="hlt">ocean</span> component. CHIME is as similar as possible to the 3rd Hadley Centre Coupled <span class="hlt">Model</span> (HadCM3) with the important exception that its <span class="hlt">ocean</span> component is based on a hybrid vertical coordinate. Power spectral analysis reveals enhanced AMOC variability for periods in the range 15-30 years. Strong AMOC conditions are associated with: (1) a Sea Surface Temperature (SST) anomaly pattern reminiscent of the Atlantic Multi-decadal Oscillation (AMO) response, but associated with variations in a northern tropical-subtropical gradient; (2) a Surface Air Temperature anomaly pattern closely linked to SST; (3) a positive North Atlantic Oscillation (NAO)-like pattern; (4) a northward shift of the Intertropical Convergence Zone. The primary mode of AMOC variability is associated with decadal changes in the Labrador Sea and the Greenland Iceland Norwegian (GIN) Seas, in both cases linked to the tropical activity about 15 years earlier. These decadal changes are controlled by the low-frequency NAO that may be associated with a rapid atmospheric teleconnection from the tropics to the extratropics. Poleward advection of salinity anomalies in the mixed layer also leads to AMOC changes that are linked to processes in the Labrador Sea. A secondary mode of AMOC variability is associated with interannual changes in the Labrador and GIN Seas, through the impact of the NAO on local surface density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712219S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712219S"><span><span class="hlt">Oceanic</span> an <span class="hlt">climatic</span> consequences of a sudden large-scale West Antarctic Ice Sheet collapse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scarff, Katie; Green, Mattias; Schmittner, Andreas</p> <p>2015-04-01</p> <p>Atmospheric warming is progressing to the point where the West Antarctic Ice Sheet (WAIS) will experience an elevated rate of discharge. The current discharge rate of WAIS is around 0.005Sv, but this rate will most likely accelerate over this century. The input of freshwater, in the form of ice, may have a profound effect on <span class="hlt">oceanic</span> circulation systems, including potentially reducing the formation of deep water in the Southern <span class="hlt">Ocean</span> and thus triggering or enhancing the bipolar seesaw. Using UVic - an intermediate complexity <span class="hlt">ocean-climate</span> <span class="hlt">model</span> - we investigate how various hosing rates from the WAIS will impact of the present and future <span class="hlt">ocean</span> circulation and <span class="hlt">climate</span>. These scenarios range from observed hosing rates (~0.005Sv) being applied for 100 years, to a total collapse of the WAIS over the next 100 years (the equivalent to a0.7Sv hosing). We show that even the present day observed rates can have a significant impact on the <span class="hlt">ocean</span> and atmospheric temperatures, and that the bipolar seesaw may indeed be enhanced by the Southern <span class="hlt">Ocean</span> hosing. Consequently, there is a speed-up of the Meridional Overturning Circulation (MOC) early on during the hosing, which leads to a warming over the North Atlantic, and a subsequent reduction in the MOC on centennial scales. The larger hosing cases show more dramatic effects with near-complete shutdowns of the MOC during the hosing. Furthermore, global warming scenarios based on the IPCC "business as usual" scenario show that the atmospheric warming will change the response of the <span class="hlt">ocean</span> to Southern <span class="hlt">Ocean</span> hosing and that the warming will dominate the perturbation. The potential feedback between changes in the <span class="hlt">ocean</span> stratification in the scenarios and tidally driven abyssal mixing via tidal conversion is also explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GMDD....6..585L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GMDD....6..585L"><span>Failure analysis of parameter-induced simulation crashes in <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lucas, D. D.; Klein, R.; Tannahill, J.; Ivanova, D.; Brandon, S.; Domyancic, D.; Zhang, Y.</p> <p>2013-01-01</p> <p>Simulations using IPCC-class <span class="hlt">climate</span> <span class="hlt">models</span> are subject to fail or crash for a variety of reasons. Quantitative analysis of the failures can yield useful insights to better understand and improve the <span class="hlt">models</span>. During the course of uncertainty quantification (UQ) ensemble simulations to assess the effects of <span class="hlt">ocean</span> <span class="hlt">model</span> parameter uncertainties on <span class="hlt">climate</span> simulations, we experienced a series of simulation crashes within the Parallel <span class="hlt">Ocean</span> Program (POP2) component of the Community <span class="hlt">Climate</span> System <span class="hlt">Model</span> (CCSM4). About 8.5% of our CCSM4 simulations failed for numerical reasons at combinations of POP2 parameter values. We apply support vector machine (SVM) classification from machine learning to quantify and predict the probability of failure as a function of the values of 18 POP2 parameters. A committee of SVM classifiers readily predicts <span class="hlt">model</span> failures in an independent validation ensemble, as assessed by the area under the receiver operating characteristic (ROC) curve metric (AUC > 0.96). The causes of the simulation failures are determined through a global sensitivity analysis. Combinations of 8 parameters related to <span class="hlt">ocean</span> mixing and viscosity from three different POP2 parameterizations are the major sources of the failures. This information can be used to improve POP2 and CCSM4 by incorporating correlations across the relevant parameters. Our method can also be used to quantify, predict, and understand simulation crashes in other complex geoscientific <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20861445','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20861445"><span>Perspectives on empirical approaches for <span class="hlt">ocean</span> color remote sensing of chlorophyll in a changing <span class="hlt">climate</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dierssen, Heidi M</p> <p>2010-10-05</p> <p>Phytoplankton biomass and productivity have been continuously monitored from <span class="hlt">ocean</span> color satellites for over a decade. Yet, the most widely used empirical approach for estimating chlorophyll a (Chl) from satellites can be in error by a factor of 5 or more. Such variability is due to differences in absorption and backscattering properties of phytoplankton and related concentrations of colored-dissolved organic matter (CDOM) and minerals. The empirical algorithms have built-in assumptions that follow the basic precept of biological oceanography--namely, oligotrophic regions with low phytoplankton biomass are populated with small phytoplankton, whereas more productive regions contain larger bloom-forming phytoplankton. With a changing world <span class="hlt">ocean</span>, phytoplankton composition may shift in response to altered environmental forcing, and CDOM and mineral concentrations may become uncoupled from phytoplankton stocks, creating further uncertainty and error in the empirical approaches. Hence, caution is warranted when using empirically derived Chl to infer <span class="hlt">climate</span>-related changes in <span class="hlt">ocean</span> biology. The Southern <span class="hlt">Ocean</span> is already experiencing <span class="hlt">climatic</span> shifts and shows substantial errors in satellite-derived Chl for different phytoplankton assemblages. Accurate global assessments of phytoplankton will require improved technology and <span class="hlt">modeling</span>, enhanced field observations, and ongoing validation of our "eyes in space."</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP41C1406G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP41C1406G"><span>Global <span class="hlt">Ocean</span> Sedimentation Patterns: Plate Tectonic History Versus <span class="hlt">Climate</span> Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goswami, A.; Reynolds, E.; Olson, P.; Hinnov, L. A.; Gnanadesikan, A.</p> <p>2014-12-01</p> <p>Global sediment data (Whittaker et al., 2013) and carbonate content data (Archer, 1996) allows examination of <span class="hlt">ocean</span> sedimentation evolution with respect to age of the underlying <span class="hlt">ocean</span> crust (Müller et al., 2008). From these data, we construct time series of <span class="hlt">ocean</span> sediment thickness and carbonate deposition rate for the Atlantic, Pacific, and Indian <span class="hlt">ocean</span> basins for the past 120 Ma. These time series are unique to each basin and reflect an integrated response to plate tectonics and <span class="hlt">climate</span> change. The goal is to parameterize <span class="hlt">ocean</span> sedimentation tied to crustal age for paleoclimate studies. For each basin, total sediment thickness and carbonate deposition rate from 0.1 x 0.1 degree cells are binned according to basement crustal age; area-corrected moments (mean, variance, etc.) are calculated for each bin. Segmented linear fits identify trends in present-day carbonate deposition rates and changes in <span class="hlt">ocean</span> sedimentation from 0 to 120 Ma. In the North and South Atlantic and Indian <span class="hlt">oceans</span>, mean sediment thickness versus crustal age is well represented by three linear segments, with the slope of each segment increasing with increasing crustal age. However, the transition age between linear segments varies among the three basins. In contrast, mean sediment thickness in the North and South Pacific <span class="hlt">oceans</span> are numerically smaller and well represented by two linear segments with slopes that decrease with increasing crustal age. These opposing trends are more consistent with the plate tectonic history of each basin being the controlling factor in sedimentation rates, rather than <span class="hlt">climate</span> change. Unlike total sediment thickness, carbonate deposition rates decrease smoothly with crustal age in all basins, with the primary controls being <span class="hlt">ocean</span> chemistry and water column depth.References: Archer, D., 1996, Global Biogeochem. Cycles 10, 159-174.Müller, R.D., et al., 2008, Science, 319, 1357-1362.Whittaker, J., et al., 2013, Geochem., Geophys., Geosyst. DOI: 10.1002/ggge.20181</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040081225&hterms=chlorophyll&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchlorophyll','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040081225&hterms=chlorophyll&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchlorophyll"><span>Patterns and Variability in Global <span class="hlt">Ocean</span> Chlorophyll: Satellite Observations and <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gregg, Watson</p> <p>2004-01-01</p> <p>Recent analyses of SeaWiFS data have shown that global <span class="hlt">ocean</span> chlorophyll has increased more than 4% since 1998. The North Pacific <span class="hlt">ocean</span> basin has increased nearly 19%. These trend analyses follow earlier results showing decadal declines in global <span class="hlt">ocean</span> chlorophyll and primary production. To understand the causes of these changes and trends we have applied the newly developed NASA <span class="hlt">Ocean</span> Biogeochemical Assimilation <span class="hlt">Model</span> (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The <span class="hlt">model</span> utilizes chlorophyll from SeaWiFS in a daily assimilation. The <span class="hlt">model</span> has in place many of the <span class="hlt">climatic</span> variables that can be expected to produce the changes observed in SeaWiFS data. This enables us to diagnose the <span class="hlt">model</span> performance, the assimilation performance, and possible causes for the increase in chlorophyll. A full discussion of the changes and trends, possible causes, <span class="hlt">modeling</span> approaches, and data assimilation will be the focus of the seminar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMNH52A..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMNH52A..08S"><span>Quantifying the role of <span class="hlt">climate</span> variability on extreme total water level impacts: An application of a full simulation <span class="hlt">model</span> to <span class="hlt">Ocean</span> Beach, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serafin, K.; Ruggiero, P.; Stockdon, H. F.; Barnard, P.; Long, J.</p> <p>2014-12-01</p> <p>Many coastal communities worldwide are vulnerable to flooding and erosion driven by extreme total water levels (TWL), potentially dangerous events produced by the combination of large waves, high tides, and high non-tidal residuals. The West coast of the United States provides an especially challenging environment to <span class="hlt">model</span> these processes due to its complex geological setting combined with uncertain forecasts for sea level rise (SLR), changes in storminess, and possible changes in the frequency of major El Niños. Our research therefore aims to develop an appropriate methodology to assess present-day and future storm-induced coastal hazards along the entire U.S. West coast, filling this information gap. We present the application of this framework in a pilot study at <span class="hlt">Ocean</span> Beach, California, a National Park site within the Golden Gate National Recreation Area where existing event-scale coastal change data can be used for <span class="hlt">model</span> calibration and verification. We use a probabilistic, full simulation TWL <span class="hlt">model</span> (TWL-FSM; Serafin and Ruggiero, in press) that captures the seasonal and interannual <span class="hlt">climatic</span> variability in extremes using functions of regional <span class="hlt">climate</span> indices, such as the Multivariate ENSO index (MEI), to represent atmospheric patterns related to the El Niño-Southern Oscillation (ENSO). In order to characterize the effect of <span class="hlt">climate</span> variability on TWL components, we refine the TWL-FSM by splitting non-tidal residuals into low (monthly mean sea level anomalies) and high frequency (storm surge) components. We also develop synthetic <span class="hlt">climate</span> indices using Markov sequences to reproduce the autocorrelated nature of ENSO behavior. With the refined TWL-FSM, we simulate each TWL component, resulting in synthetic TWL records providing robust estimates of extreme return level events (e.g., the 100-yr event) and the ability to examine the relative contribution of each TWL component to these extreme events. Extreme return levels are then used to drive storm impact <span class="hlt">models</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.U23A..04K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.U23A..04K"><span>The <span class="hlt">Climate</span> Science Special Report: Rising Seas and Changing <span class="hlt">Oceans</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kopp, R. E.</p> <p>2017-12-01</p> <p>GMSL has risen by about 16-21 cm since 1900. <span class="hlt">Ocean</span> heat content has increased at all depths since the 1960s, and global mean sea-surface temperature increased 0.7°C/century between 1900 to 2016. Human activity contributed substantially to generating a rate of GMSL rise since 1900 faster than during any preceding century in at least 2800 years. A new set of six sea-level rise scenarios, spanning a range from 30 cm to 250 cm of 21st century GMSL rise, were developed for the CSSR. The lower scenario is based on linearly extrapolating the past two decades' rate of rise. The upper scenario is informed by literature estimates of maximum physically plausible values, observations indicating the onset of marine ice sheet instability in parts of West Antarctica, and <span class="hlt">modeling</span> of ice-cliff and ice-shelf instability mechanisms. The new scenarios include localized projections along US coastlines. There is significant variability around the US, with rates of rise likely greater than GMSL rise in the US Northeast and the western Gulf of Mexico. Under scenarios involving extreme Antarctic contributions, regional rise would be greater than GMSL rise along almost all US coastlines. Historical sea-level rise has already driven a 5- to 10-fold increase in minor tidal flooding in several US coastal cities since the 1960s. Under the CSSR's Intermediate sea-level rise scenario (1.0 m of GMSL rise in 2100) , a majority of NOAA tide gauge locations will by 2040 experience the historical 5-year coastal flood about 5 times per year. <span class="hlt">Ocean</span> changes are not limited to rising sea levels. <span class="hlt">Ocean</span> pH is decreasing at a rate that may be unparalleled in the last 66 million years. Along coastlines, <span class="hlt">ocean</span> acidification can be enhanced by changes in the upwelling (particularly along the US Pacific Coast); by episodic, <span class="hlt">climate</span> change-enhanced increases in freshwater input (particularly along the US Atlantic Coast); and by the enhancement of biological respiration by nutrient runoff. <span class="hlt">Climate</span> <span class="hlt">models</span> project</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GMD....10.4723G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GMD....10.4723G"><span>231Pa and 230Th in the <span class="hlt">ocean</span> <span class="hlt">model</span> of the Community Earth System <span class="hlt">Model</span> (CESM1.3)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gu, Sifan; Liu, Zhengyu</p> <p>2017-12-01</p> <p>The sediment 231Pa / 230Th activity ratio is emerging as an important proxy for deep <span class="hlt">ocean</span> circulation in the past. In order to allow for a direct <span class="hlt">model</span>-data comparison and to improve our understanding of the sediment 231Pa / 230Th activity ratio, we implement 231Pa and 230Th in the <span class="hlt">ocean</span> component of the Community Earth System <span class="hlt">Model</span> (CESM). In addition to the fully coupled implementation of the scavenging behavior of 231Pa and 230Th with the active marine ecosystem module (particle-coupled: hereafter p-coupled), another form of 231Pa and 230Th have also been implemented with prescribed particle flux fields of the present <span class="hlt">climate</span> (particle-fixed: hereafter p-fixed). The comparison of the two forms of 231Pa and 230Th helps to isolate the influence of the particle fluxes from that of <span class="hlt">ocean</span> circulation. Under present-day <span class="hlt">climate</span> forcing, our <span class="hlt">model</span> is able to simulate water column 231Pa and 230Th activity and the sediment 231Pa / 230Th activity ratio in good agreement with available observations. In addition, in response to freshwater forcing, the p-coupled and p-fixed sediment 231Pa / 230Th activity ratios behave similarly over large areas of low productivity on long timescales, but can differ substantially in some regions of high productivity and on short timescales, indicating the importance of biological productivity in addition to <span class="hlt">ocean</span> transport. Therefore, our <span class="hlt">model</span> provides a potentially powerful tool to help the interpretation of sediment 231Pa / 230Th reconstructions and to improve our understanding of past <span class="hlt">ocean</span> circulation and <span class="hlt">climate</span> changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSED44B1718M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSED44B1718M"><span>EarthLabs Modules: Engaging Students In Extended, Rigorous Investigations Of The <span class="hlt">Ocean</span>, <span class="hlt">Climate</span> and Weather</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manley, J.; Chegwidden, D.; Mote, A. S.; Ledley, T. S.; Lynds, S. E.; Haddad, N.; Ellins, K.</p> <p>2016-02-01</p> <p>EarthLabs, envisioned as a national <span class="hlt">model</span> for high school Earth or Environmental Science lab courses, is adaptable for both undergraduate middle school students. The collection includes ten online modules that combine to feature a global view of our planet as a dynamic, interconnected system, by engaging learners in extended investigations. EarthLabs support state and national guidelines, including the NGSS, for science content. Four modules directly guide students to discover vital aspects of the <span class="hlt">oceans</span> while five other modules incorporate <span class="hlt">ocean</span> sciences in order to complete an understanding of Earth's <span class="hlt">climate</span> system. Students gain a broad perspective on the key role <span class="hlt">oceans</span> play in fishing industry, droughts, coral reefs, hurricanes, the carbon cycle, as well as life on land and in the seas to drive our changing <span class="hlt">climate</span> by interacting with scientific research data, manipulating satellite imagery, numerical data, computer visualizations, experiments, and video tutorials. Students explore Earth system processes and build quantitative skills that enable them to objectively evaluate scientific findings for themselves as they move through ordered sequences that guide the learning. As a robust collection, EarthLabs modules engage students in extended, rigorous investigations allowing a deeper understanding of the <span class="hlt">ocean</span>, <span class="hlt">climate</span> and weather. This presentation provides an overview of the ten curriculum modules that comprise the EarthLabs collection developed by TERC and found at http://serc.carleton.edu/earthlabs/index.html. Evaluation data on the effectiveness and use in secondary education classrooms will be summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JCli...12.1892J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JCli...12.1892J"><span>Exploratory Long-Range <span class="hlt">Models</span> to Estimate Summer <span class="hlt">Climate</span> Variability over Southern Africa.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jury, Mark R.; Mulenga, Henry M.; Mason, Simon J.</p> <p>1999-07-01</p> <p>Teleconnection predictors are explored using multivariate regression <span class="hlt">models</span> in an effort to estimate southern African summer rainfall and <span class="hlt">climate</span> impacts one season in advance. The preliminary statistical formulations include many variables influenced by the El Niño-Southern Oscillation (ENSO) such as tropical sea surface temperatures (SST) in the Indian and Atlantic <span class="hlt">Oceans</span>. Atmospheric circulation responses to ENSO include the alternation of tropical zonal winds over Africa and changes in convective activity within <span class="hlt">oceanic</span> monsoon troughs. Numerous hemispheric-scale datasets are employed to extract predictors and include global indexes (Southern Oscillation index and quasi-biennial oscillation), SST principal component scores for the global <span class="hlt">oceans</span>, indexes of tropical convection (outgoing longwave radiation), air pressure, and surface and upper winds over the Indian and Atlantic <span class="hlt">Oceans</span>. <span class="hlt">Climatic</span> targets include subseasonal, area-averaged rainfall over South Africa and the Zambezi river basin, and South Africa's annual maize yield. Predictors and targets overlap in the years 1971-93, the defined training period. Each target time series is fitted by an optimum group of predictors from the preceding spring, in a linear multivariate formulation. To limit artificial skill, predictors are restricted to three, providing 17 degrees of freedom. <span class="hlt">Models</span> with colinear predictors are screened out, and persistence of the target time series is considered. The late summer rainfall <span class="hlt">models</span> achieve a mean r2 fit of 72%, contributed largely through ENSO modulation. Early summer rainfall cross validation correlations are lower (61%). A conceptual understanding of the <span class="hlt">climate</span> dynamics and <span class="hlt">ocean</span>-atmosphere coupling processes inherent in the exploratory <span class="hlt">models</span> is outlined.Seasonal outlooks based on the exploratory <span class="hlt">models</span> could help mitigate the impacts of southern Africa's fluctuating <span class="hlt">climate</span>. It is believed that an advance warning of drought risk and seasonal rainfall prospects will</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913002F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913002F"><span>Description and evaluation of the Earth System Regional <span class="hlt">Climate</span> <span class="hlt">Model</span> (RegCM-ES)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farneti, Riccardo; Sitz, Lina; Di Sante, Fabio; Fuentes-Franco, Ramon; Coppola, Erika; Mariotti, Laura; Reale, Marco; Sannino, Gianmaria; Barreiro, Marcelo; Nogherotto, Rita; Giuliani, Graziano; Graffino, Giorgio; Solidoro, Cosimo; Giorgi, Filippo</p> <p>2017-04-01</p> <p>The increasing availability of satellite remote sensing data, of high temporal frequency and spatial resolution, has provided a new and enhanced view of the global <span class="hlt">ocean</span> and atmosphere, revealing strong air-sea coupling processes throughout the <span class="hlt">ocean</span> basins. In order to obtain an accurate representation and better understanding of the <span class="hlt">climate</span> system, its variability and change, the inclusion of all mechanisms of interaction among the different sub-components, at high temporal and spatial resolution, becomes ever more desirable. Recently, global coupled <span class="hlt">models</span> have been able to progressively refine their horizontal resolution to attempt to resolve smaller-scale processes. However, regional coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">models</span> can achieve even finer resolutions and provide additional information on the mechanisms of air-sea interactions and feedbacks. Here we describe a new, state-of-the-art, Earth System Regional <span class="hlt">Climate</span> <span class="hlt">Model</span> (RegCM-ES). RegCM-ES presently includes the coupling between atmosphere, <span class="hlt">ocean</span>, land surface and sea-ice components, as well as an hydrological and <span class="hlt">ocean</span> biogeochemistry <span class="hlt">model</span>. The regional coupled <span class="hlt">model</span> has been implemented and tested over some of the COordinated Regional <span class="hlt">climate</span> Downscaling Experiment (CORDEX) domains. RegCM-ES has shown improvements in the representation of precipitation and SST fields over the tested domains, as well as realistic representations of coupled air-sea processes and interactions. The RegCM-ES <span class="hlt">model</span>, which can be easily implemented over any regional domain of interest, is open source making it suitable for usage by the large scientific community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSED34A1685H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSED34A1685H"><span><span class="hlt">Ocean</span> Sciences Sequence for Grades 6-8: <span class="hlt">Climate</span> Change Curriculum Developed Through a Collaboration Between Scientists and Educators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Halversen, C.; Weiss, E. L.; Pedemonte, S.</p> <p>2016-02-01</p> <p>Today's youth have been tasked with the overwhelming job of addressing the world's <span class="hlt">climate</span> future. The students who will become the scientists, policy makers, and citizens of tomorrow must gain a robust understanding of the causes and effects of <span class="hlt">climate</span> change, as well as possible adaptation strategies. Currently, few high quality curriculum materials exist that address <span class="hlt">climate</span> change in a developmentally appropriate manner. The NOAA-funded <span class="hlt">Ocean</span> Sciences Sequence for Grades 6-8: The <span class="hlt">Ocean</span>-Atmosphere Connection and <span class="hlt">Climate</span> Change (OSS) addresses this gap by providing teachers with scientifically accurate <span class="hlt">climate</span> change curriculum that hits on some of the most salient points in <span class="hlt">climate</span> science, while simultaneously developing students' science process skills. OSS was developed through a collaboration between some of the nation's leading <span class="hlt">ocean</span> and <span class="hlt">climate</span> scientists and the Lawrence Hall of Science's highly qualified curriculum development team. Scientists were active partners throughout the entire development process, from initial brainstorming of key concepts and creating the conceptual storyline for the curriculum to final review of the content and activities. The goal was to focus strategically and effectively on core concepts within <span class="hlt">ocean</span> and <span class="hlt">climate</span> sciences that students should understand. OSS was designed in accordance with the latest research from the learning sciences and provides numerous opportunities for students to develop facility with science practices by "doing" science.Through hands-on activities, technology, informational readings, and embedded assessments, OSS deeply addresses a significant number of standards from the Next Generation Science Standards and is being used by many teachers as they explore the shifts required by NGSS. It also aligns with the <span class="hlt">Ocean</span> Literacy and <span class="hlt">Climate</span> Literacy Frameworks. OSS comprises 33 45-minute sessions organized into three thematic units, each driven by an exploratory question: (1) How do the <span class="hlt">ocean</span> and atmosphere</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.4873C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.4873C"><span>Reconstructing the <span class="hlt">climate</span> states of the Late Pleistocene with the MIROC <span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, Wing-Le; Abe-Ouchi, Ayako; O'ishi, Ryouta; Takahashi, Kunio</p> <p>2014-05-01</p> <p>The Late Pleistocene was a period which lasted from the Eemian interglacial period to the start of the warm Holocene and was characterized mostly by widespread glacial ice. It was also a period which saw modern humans spread throughout the world and other species of the same genus, like the Neanderthals, become extinct. Various hypotheses have been put forward to explain the extinction of Neanderthals, about 30,000 years ago. Among these is one which involves changes in past <span class="hlt">climate</span> and the inability of Neanderthals to adapt to such changes. The last traces of Neanderthals coincide with the end of Marine Isotope Stage 3 (MIS3) which was marked by large fluctuations in temperature and so-called Heinrich events, as suggested by geochemical records from ice cores. It is thought that melting sea ice or icebergs originating from the Laurentide ice sheet led to a large discharge of freshwater into the North Atlantic <span class="hlt">Ocean</span> during the Heinrich events and severely weakened the Atlantic meridional overturning circulation, with important environmental ramifications across parts of Europe such as sharp decreases in temperature and reduction in forest cover. In order to assess the effects of past <span class="hlt">climate</span> change on past hominin migration and on the extinction of certain species, it is first important to have a good understanding of the past <span class="hlt">climate</span> itself. In this study, we have used three variants of MIROC (The <span class="hlt">Model</span> for Interdisciplinary Research on <span class="hlt">Climate</span>), a global <span class="hlt">climate</span> <span class="hlt">model</span>, for a time slice experiment within the Late Pleistocene: two mid-resolution <span class="hlt">models</span> (an atmosphere <span class="hlt">model</span> and a coupled atmosphere-<span class="hlt">ocean</span> <span class="hlt">model</span>) and a high-resolution atmosphere <span class="hlt">model</span>. To obtain a fuller picture, we also look at a cool stadial state as obtained from a 'freshwater hosing' coupled-<span class="hlt">model</span> experiment, designed to mimic the effects of freshwater discharge in the North Atlantic. We next use the sea surface temperature response from this experiment to drive the atmosphere <span class="hlt">models</span>. We discuss</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14...79K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14...79K"><span><span class="hlt">Climate</span> extremes in the Pacific: improving seasonal prediction of tropical cyclones and extreme <span class="hlt">ocean</span> temperatures to improve resilience</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuleshov, Y.; Jones, D.; Spillman, C. M.</p> <p>2012-04-01</p> <p><span class="hlt">Climate</span> change and <span class="hlt">climate</span> extremes have a major impact on Australia and Pacific Island countries. Of particular concern are tropical cyclones and extreme <span class="hlt">ocean</span> temperatures, the first being the most destructive events for terrestrial systems, while the latter has the potential to devastate <span class="hlt">ocean</span> ecosystems through coral bleaching. As a practical response to <span class="hlt">climate</span> change, under the Pacific-Australia <span class="hlt">Climate</span> Change Science and Adaptation Planning program (PACCSAP), we are developing enhanced web-based information tools for providing seasonal forecasts for <span class="hlt">climatic</span> extremes in the Western Pacific. Tropical cyclones are the most destructive weather systems that impact on coastal areas. Interannual variability in the intensity and distribution of tropical cyclones is large, and presently greater than any trends that are ascribable to <span class="hlt">climate</span> change. In the warming environment, predicting tropical cyclone occurrence based on historical relationships, with predictors such as sea surface temperatures (SSTs) now frequently lying outside of the range of past variability meaning that it is not possible to find historical analogues for the seasonal conditions often faced by Pacific countries. Elevated SSTs are the primary trigger for mass coral bleaching events, which can lead to widespread damage and mortality on reef systems. Degraded coral reefs present many problems, including long-term loss of tourism and potential loss or degradation of fisheries. The monitoring and prediction of thermal stress events enables the support of a range of adaptive and management activities that could improve reef resilience to extreme conditions. Using the <span class="hlt">climate</span> <span class="hlt">model</span> POAMA (Predictive <span class="hlt">Ocean</span>-Atmosphere <span class="hlt">Model</span> for Australia), we aim to improve accuracy of seasonal forecasts of tropical cyclone activity and extreme SSTs for the regions of Western Pacific. Improved knowledge of extreme <span class="hlt">climatic</span> events, with the assistance of tailored forecast tools, will help enhance the resilience and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.9058H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.9058H"><span>Reconstructing Holocene <span class="hlt">climate</span> using a <span class="hlt">climate</span> <span class="hlt">model</span>: <span class="hlt">Model</span> strategy and preliminary results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haberkorn, K.; Blender, R.; Lunkeit, F.; Fraedrich, K.</p> <p>2009-04-01</p> <p>An Earth system <span class="hlt">model</span> of intermediate complexity (Planet Simulator; PlaSim) is used to reconstruct Holocene <span class="hlt">climate</span> based on proxy data. The Planet Simulator is a user friendly general circulation <span class="hlt">model</span> (GCM) suitable for palaeoclimate research. Its easy handling and the modular structure allow for fast and problem dependent simulations. The spectral <span class="hlt">model</span> is based on the moist primitive equations conserving momentum, mass, energy and moisture. Besides the atmospheric part, a mixed layer-<span class="hlt">ocean</span> with sea ice and a land surface with biosphere are included. The present-day <span class="hlt">climate</span> of PlaSim, based on an AMIP II control-run (T21/10L resolution), shows reasonable agreement with ERA-40 reanalysis data. Combining PlaSim with a socio-technological <span class="hlt">model</span> (GLUES; DFG priority project INTERDYNAMIK) provides improved knowledge on the shift from hunting-gathering to agropastoral subsistence societies. This is achieved by a data assimilation approach, incorporating proxy time series into PlaSim to initialize palaeoclimate simulations during the Holocene. For this, the following strategy is applied: The sensitivities of the terrestrial PlaSim <span class="hlt">climate</span> are determined with respect to sea surface temperature (SST) anomalies. Here, the focus is the impact of regionally varying SST both in the tropics and the Northern Hemisphere mid-latitudes. The inverse of these sensitivities is used to determine the SST conditions necessary for the nudging of land and coastal proxy <span class="hlt">climates</span>. Preliminary results indicate the potential, the uncertainty and the limitations of the method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2387D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2387D"><span><span class="hlt">Ocean</span> circulation drifts in multi-millennial <span class="hlt">climate</span> simulations: the role of salinity corrections and <span class="hlt">climate</span> feedbacks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dentith, Jennifer E.; Ivanovic, Ruza F.; Gregoire, Lauren J.; Tindall, Julia C.; Smith, Robin S.</p> <p>2018-05-01</p> <p>Low-resolution, complex general circulation <span class="hlt">models</span> (GCMs) are valuable tools for studying the Earth system on multi-millennial timescales. However, slowly evolving salinity drifts can cause large shifts in <span class="hlt">climatic</span> and <span class="hlt">oceanic</span> regimes over thousands of years. We test two different schemes for neutralising unforced salinity drifts in the FAMOUS GCM: surface flux correction and volumetric flux correction. Although both methods successfully maintain a steady global mean salinity, local drifts and subsequent feedbacks promote cooling (≈ 4 °C over 6000 years) and freshening (≈ 2 psu over 6000 years) in the North Atlantic <span class="hlt">Ocean</span>, and gradual warming (≈ 0.2 °C per millennium) and salinification (≈ 0.15 psu per millennium) in the North Pacific <span class="hlt">Ocean</span>. Changes in the surface density in these regions affect the meridional overturning circulation (MOC), such that, after several millennia, the Atlantic MOC (AMOC) is in a collapsed state, and there is a strong, deep Pacific MOC (PMOC). Furthermore, the AMOC exhibits a period of metastability, which is only identifiable with run lengths in excess of 1500 years. We also compare simulations with two different land surface schemes, demonstrating that small biases in the surface <span class="hlt">climate</span> may cause regional salinity drifts and significant shifts in the MOC (weakening of the AMOC and the initiation then invigoration of PMOC), even when the global hydrological cycle has been forcibly closed. Although there is no specific precursor to the simulated AMOC collapse, the northwest North Pacific and northeast North Atlantic are important areas that should be closely monitored for trends arising from such biases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23932473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23932473"><span><span class="hlt">Climate</span> change and the <span class="hlt">oceans</span>--what does the future hold?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bijma, Jelle; Pörtner, Hans-O; Yesson, Chris; Rogers, Alex D</p> <p>2013-09-30</p> <p>The <span class="hlt">ocean</span> has been shielding the earth from the worst effects of rapid <span class="hlt">climate</span> change by absorbing excess carbon dioxide from the atmosphere. This absorption of CO2 is driving the <span class="hlt">ocean</span> along the pH gradient towards more acidic conditions. At the same time <span class="hlt">ocean</span> warming is having pronounced impacts on the composition, structure and functions of marine ecosystems. Warming, freshening (in some areas) and associated stratification are driving a trend in <span class="hlt">ocean</span> deoxygenation, which is being enhanced in parts of the coastal zone by upwelling of hypoxic deep water. The combined impact of warming, acidification and deoxygenation are already having a dramatic effect on the flora and fauna of the <span class="hlt">oceans</span> with significant changes in distribution of populations, and decline of sensitive species. In many cases, the impacts of warming, acidification and deoxygenation are increased by the effects of other human impacts, such as pollution, eutrophication and overfishing. The interactive effects of this deadly trio mirrors similar events in the Earth's past, which were often coupled with extinctions of major species' groups. Here we review the observed impacts and, using past episodes in the Earth's history, set out what the future may hold if carbon emissions and <span class="hlt">climate</span> change are not significantly reduced with more or less immediate effect. Copyright © 2013. Published by Elsevier Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26163010','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26163010"><span>Effects of Southern Hemisphere Wind Changes on the Meridional Overturning Circulation in <span class="hlt">Ocean</span> <span class="hlt">Models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gent, Peter R</p> <p>2016-01-01</p> <p>Observations show that the Southern Hemisphere zonal wind stress maximum has increased significantly over the past 30 years. Eddy-resolving <span class="hlt">ocean</span> <span class="hlt">models</span> show that the resulting increase in the Southern <span class="hlt">Ocean</span> mean flow meridional overturning circulation (MOC) is partially compensated by an increase in the eddy MOC. This effect can be reproduced in the non-eddy-resolving <span class="hlt">ocean</span> component of a <span class="hlt">climate</span> <span class="hlt">model</span>, providing the eddy parameterization coefficient is variable and not a constant. If the coefficient is a constant, then the Southern <span class="hlt">Ocean</span> mean MOC change is balanced by an unrealistically large change in the Atlantic <span class="hlt">Ocean</span> MOC. Southern <span class="hlt">Ocean</span> eddy compensation means that Southern Hemisphere winds cannot be the dominant mechanism driving midlatitude North Atlantic MOC variability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3974B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3974B"><span>Impact of opening of the Central America Seaway on <span class="hlt">climate</span> in a coupled atmosphere-<span class="hlt">ocean</span>-sea-ice <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barrier, N.; Ferreira, D.; Marshall, J.</p> <p>2012-04-01</p> <p>We investigate the <span class="hlt">climatic</span> impact of opening the Central America Seaway (CAS) in a coupled atmosphere-<span class="hlt">ocean</span>-sea-ice <span class="hlt">model</span>. A highly idealized land distribution is employed in which two meridional barriers extend from the North Pole in to the southern hemisphere, thus dividing the <span class="hlt">ocean</span> in to a large basin, a small basin and a circumpolar flow around the South Pole. Such a configuration captures the essential zonal and inter-hemispheric asymmetries of the current <span class="hlt">climate</span>. These simple geometrical constraints are sufficient to localize the deep-reaching meridional overturning circulation (MOC) to the northern extremity of the small basin. Given this reference experiment, we open up an analogue of the Central America Seaway on the western margin of the small basin north of the equator. Both deep and shallow passageways are considered. We find that although a major reorganization of <span class="hlt">ocean</span> circulation occurs, along with significant local water-mass changes, global heat and freshwater meridional transports are largely unchanged, as are temperatures over the North Pole. In particular we do not observe a weakening of the MOC in the small basin, with salinity exchange between the large basin playing only a minor role. The simplicity of the geometrical configuration used in our experiments enables us to tease apart exactly what is going on. Experiments in which the salinity and temperature states of the small and large basins are interchanged, for example, show that our solutions are robust, with deep convection returning to the small basin after 800 years or so. Our experiments suggest to us that the closing of the CAS alone is not sufficient to lead to the onset of northern hemisphere glaciations 2 Ma years or so ago.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970003259','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970003259"><span><span class="hlt">Modeling</span> <span class="hlt">Climate</span> Change in the Absence of <span class="hlt">Climate</span> Change Data. Editorial Comment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Skiles, J. W.</p> <p>1995-01-01</p> <p>Practitioners of <span class="hlt">climate</span> change prediction base many of their future <span class="hlt">climate</span> scenarios on General Circulation <span class="hlt">Models</span> (GCM's), each <span class="hlt">model</span> with differing assumptions and parameter requirements. For representing the atmosphere, GCM's typically contain equations for calculating motion of particles, thermodynamics and radiation, and continuity of water vapor. Hydrology and heat balance are usually included for continents, and sea ice and heat balance are included for <span class="hlt">oceans</span>. The current issue of this journal contains a paper by Van Blarcum et al. (1995) that predicts runoff from nine high-latitude rivers under a doubled CO2 atmosphere. The paper is important since river flow is an indicator variable for <span class="hlt">climate</span> change. The authors show that precipitation will increase under the imposed perturbations and that owing to higher temperatures earlier in the year that cause the snow pack to melt sooner, runoff will also increase. They base their simulations on output from a GCM coupled with an interesting water routing scheme they have devised. <span class="hlt">Climate</span> change <span class="hlt">models</span> have been linked to other <span class="hlt">models</span> to predict deforestation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PNAS..112E5777D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PNAS..112E5777D"><span>Catalogue of abrupt shifts in Intergovernmental Panel on <span class="hlt">Climate</span> Change <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drijfhout, Sybren; Bathiany, Sebastian; Beaulieu, Claudie; Brovkin, Victor; Claussen, Martin; Huntingford, Chris; Scheffer, Marten; Sgubin, Giovanni; Swingedouw, Didier</p> <p>2015-10-01</p> <p>Abrupt transitions of regional <span class="hlt">climate</span> in response to the gradual rise in atmospheric greenhouse gas concentrations are notoriously difficult to foresee. However, such events could be particularly challenging in view of the capacity required for society and ecosystems to adapt to them. We present, to our knowledge, the first systematic screening of the massive <span class="hlt">climate</span> <span class="hlt">model</span> ensemble informing the recent Intergovernmental Panel on <span class="hlt">Climate</span> Change report, and reveal evidence of 37 forced regional abrupt changes in the <span class="hlt">ocean</span>, sea ice, snow cover, permafrost, and terrestrial biosphere that arise after a certain global temperature increase. Eighteen out of 37 events occur for global warming levels of less than 2°, a threshold sometimes presented as a safe limit. Although most <span class="hlt">models</span> predict one or more such events, any specific occurrence typically appears in only a few <span class="hlt">models</span>. We find no compelling evidence for a general relation between the overall number of abrupt shifts and the level of global warming. However, we do note that abrupt changes in <span class="hlt">ocean</span> circulation occur more often for moderate warming (less than 2°), whereas over land they occur more often for warming larger than 2°. Using a basic proportion test, however, we find that the number of abrupt shifts identified in Representative Concentration Pathway (RCP) 8.5 scenarios is significantly larger than in other scenarios of lower radiative forcing. This suggests the potential for a gradual trend of destabilization of the <span class="hlt">climate</span> with respect to such shifts, due to increasing global mean temperature change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4629371','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4629371"><span>Catalogue of abrupt shifts in Intergovernmental Panel on <span class="hlt">Climate</span> Change <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Drijfhout, Sybren; Bathiany, Sebastian; Beaulieu, Claudie; Brovkin, Victor; Claussen, Martin; Huntingford, Chris; Scheffer, Marten; Sgubin, Giovanni; Swingedouw, Didier</p> <p>2015-01-01</p> <p>Abrupt transitions of regional <span class="hlt">climate</span> in response to the gradual rise in atmospheric greenhouse gas concentrations are notoriously difficult to foresee. However, such events could be particularly challenging in view of the capacity required for society and ecosystems to adapt to them. We present, to our knowledge, the first systematic screening of the massive <span class="hlt">climate</span> <span class="hlt">model</span> ensemble informing the recent Intergovernmental Panel on <span class="hlt">Climate</span> Change report, and reveal evidence of 37 forced regional abrupt changes in the <span class="hlt">ocean</span>, sea ice, snow cover, permafrost, and terrestrial biosphere that arise after a certain global temperature increase. Eighteen out of 37 events occur for global warming levels of less than 2°, a threshold sometimes presented as a safe limit. Although most <span class="hlt">models</span> predict one or more such events, any specific occurrence typically appears in only a few <span class="hlt">models</span>. We find no compelling evidence for a general relation between the overall number of abrupt shifts and the level of global warming. However, we do note that abrupt changes in <span class="hlt">ocean</span> circulation occur more often for moderate warming (less than 2°), whereas over land they occur more often for warming larger than 2°. Using a basic proportion test, however, we find that the number of abrupt shifts identified in Representative Concentration Pathway (RCP) 8.5 scenarios is significantly larger than in other scenarios of lower radiative forcing. This suggests the potential for a gradual trend of destabilization of the <span class="hlt">climate</span> with respect to such shifts, due to increasing global mean temperature change. PMID:26460042</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26460042','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26460042"><span>Catalogue of abrupt shifts in Intergovernmental Panel on <span class="hlt">Climate</span> Change <span class="hlt">climate</span> <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drijfhout, Sybren; Bathiany, Sebastian; Beaulieu, Claudie; Brovkin, Victor; Claussen, Martin; Huntingford, Chris; Scheffer, Marten; Sgubin, Giovanni; Swingedouw, Didier</p> <p>2015-10-27</p> <p>Abrupt transitions of regional <span class="hlt">climate</span> in response to the gradual rise in atmospheric greenhouse gas concentrations are notoriously difficult to foresee. However, such events could be particularly challenging in view of the capacity required for society and ecosystems to adapt to them. We present, to our knowledge, the first systematic screening of the massive <span class="hlt">climate</span> <span class="hlt">model</span> ensemble informing the recent Intergovernmental Panel on <span class="hlt">Climate</span> Change report, and reveal evidence of 37 forced regional abrupt changes in the <span class="hlt">ocean</span>, sea ice, snow cover, permafrost, and terrestrial biosphere that arise after a certain global temperature increase. Eighteen out of 37 events occur for global warming levels of less than 2°, a threshold sometimes presented as a safe limit. Although most <span class="hlt">models</span> predict one or more such events, any specific occurrence typically appears in only a few <span class="hlt">models</span>. We find no compelling evidence for a general relation between the overall number of abrupt shifts and the level of global warming. However, we do note that abrupt changes in <span class="hlt">ocean</span> circulation occur more often for moderate warming (less than 2°), whereas over land they occur more often for warming larger than 2°. Using a basic proportion test, however, we find that the number of abrupt shifts identified in Representative Concentration Pathway (RCP) 8.5 scenarios is significantly larger than in other scenarios of lower radiative forcing. This suggests the potential for a gradual trend of destabilization of the <span class="hlt">climate</span> with respect to such shifts, due to increasing global mean temperature change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-12-13/pdf/2012-30152.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-12-13/pdf/2012-30152.pdf"><span>77 FR 74174 - National <span class="hlt">Oceanic</span> and Atmospheric Administration (NOAA) National <span class="hlt">Climate</span> Assessment and...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-12-13</p> <p>... DEPARTMENT OF COMMERCE National <span class="hlt">Oceanic</span> and Atmospheric Administration (NOAA) National <span class="hlt">Climate</span>... NOAA National <span class="hlt">Climate</span> Assessment and Development Advisory Committee (NCADAC). Time and Date: The..., DC 20006. The public will not be able to dial into the call. Please check the National <span class="hlt">Climate</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A51G3118I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A51G3118I"><span>Regional <span class="hlt">climate</span> projection of the Maritime Continent using the MIT Regional <span class="hlt">Climate</span> <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>IM, E. S.; Eltahir, E. A. B.</p> <p>2014-12-01</p> <p>Given that warming of the <span class="hlt">climate</span> system is unequivocal (IPCC AR5), accurate assessment of future <span class="hlt">climate</span> is essential to understand the impact of <span class="hlt">climate</span> change due to global warming. <span class="hlt">Modelling</span> the <span class="hlt">climate</span> change of the Maritime Continent is particularly challenge, showing a high degree of uncertainty. Compared to other regions, <span class="hlt">model</span> agreement of future projections in response to anthropogenic emission forcings is much less. Furthermore, the spatial and temporal behaviors of <span class="hlt">climate</span> projections seem to vary significantly due to a complex geographical condition and a wide range of scale interactions. For the fine-scale <span class="hlt">climate</span> information (27 km) suitable for representing the complexity of <span class="hlt">climate</span> change over the Maritime Continent, dynamical downscaling is performed using the MIT regional <span class="hlt">climate</span> <span class="hlt">model</span> (MRCM) during two thirty-year period for reference (1970-1999) and future (2070-2099) <span class="hlt">climate</span>. Initial and boundary conditions are provided by Community Earth System <span class="hlt">Model</span> (CESM) simulations under the emission scenarios projected by MIT Integrated Global System <span class="hlt">Model</span> (IGSM). Changes in mean <span class="hlt">climate</span> as well as the frequency and intensity of extreme <span class="hlt">climate</span> events are investigated at various temporal and spatial scales. Our analysis is primarily centered on the different behavior of changes in convective and large-scale precipitation over land vs. <span class="hlt">ocean</span> during dry vs. wet season. In addition, we attempt to find the added value to downscaled results over the Maritime Continent through the comparison between MRCM and CESM projection. Acknowledgements.This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's Center for Environmental Sensing and <span class="hlt">Modeling</span> interdisciplinary research program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5718423','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5718423"><span>Seafarer citizen scientist <span class="hlt">ocean</span> transparency data as a resource for phytoplankton and <span class="hlt">climate</span> research</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Seafarers, Secchi Disk; Lavender, Samantha; Beaugrand, Gregory; Crotty, David; Evans, Jake</p> <p>2017-01-01</p> <p>The oceans’ phytoplankton that underpin the marine food chain appear to be changing in abundance due to global <span class="hlt">climate</span> change. Here, we compare the first four years of data from a citizen science <span class="hlt">ocean</span> transparency study, conducted by seafarers using home-made Secchi Disks and a free Smartphone application called Secchi, with contemporaneous satellite <span class="hlt">ocean</span> colour measurements. Our results show seafarers collect useful Secchi Disk measurements of <span class="hlt">ocean</span> transparency that could help future assessments of <span class="hlt">climate</span>-induced changes in the phytoplankton when used to extend historical Secchi Disk data. PMID:29211734</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009468','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009468"><span>Using the NASA Giovanni DICCE Portal to Investigate Land-<span class="hlt">Ocean</span> Linkages with Satellite and <span class="hlt">Model</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Acker, James G.; Zalles, Daniel; Krumhansl, Ruth</p> <p>2012-01-01</p> <p>Data-enhanced Investigations for <span class="hlt">Climate</span> Change Education (DICCE), a NASA <span class="hlt">climate</span> change education project, employs the NASA Giovanni data system to enable teachers to create <span class="hlt">climate</span>-related classroom projects using selected satellite and assimilated <span class="hlt">model</span> data. The easy-to-use DICCE Giovanni portal (DICCE-G) provides data parameters relevant to <span class="hlt">oceanic</span>, terrestrial, and atmospheric processes. Participants will explore land-<span class="hlt">ocean</span> linkages using the available data in the DICCE-G portal, in particular focusing on temperature, <span class="hlt">ocean</span> biology, and precipitation variability related to El Ni?o and La Ni?a events. The demonstration includes the enhanced information for educators developed for the DICCE-G portal. The prototype DICCE Learning Environment (DICCE-LE) for classroom project development will also be demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1410025-mixed-phase-cloud-physics-southern-ocean-cloud-feedback-climate-models','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1410025-mixed-phase-cloud-physics-southern-ocean-cloud-feedback-climate-models"><span>Mixed-phase cloud physics and Southern <span class="hlt">Ocean</span> cloud feedback in <span class="hlt">climate</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>McCoy, Daniel T.; Hartmann, Dennis L.; Zelinka, Mark D.; ...</p> <p>2015-08-21</p> <p>Increasing optical depth poleward of 45° is a robust response to warming in global <span class="hlt">climate</span> <span class="hlt">models</span>. Much of this cloud optical depth increase has been hypothesized to be due to transitions from ice-dominated to liquid-dominated mixed-phase cloud. In this study, the importance of liquid-ice partitioning for the optical depth feedback is quantified for 19 Coupled <span class="hlt">Model</span> Intercomparison Project Phase 5 <span class="hlt">models</span>. All <span class="hlt">models</span> show a monotonic partitioning of ice and liquid as a function of temperature, but the temperature at which ice and liquid are equally mixed (the glaciation temperature) varies by as much as 40 K across <span class="hlt">models</span>. Modelsmore » that have a higher glaciation temperature are found to have a smaller climatological liquid water path (LWP) and condensed water path and experience a larger increase in LWP as the <span class="hlt">climate</span> warms. The ice-liquid partitioning curve of each <span class="hlt">model</span> may be used to calculate the response of LWP to warming. It is found that the repartitioning between ice and liquid in a warming <span class="hlt">climate</span> contributes at least 20% to 80% of the increase in LWP as the <span class="hlt">climate</span> warms, depending on <span class="hlt">model</span>. Intermodel differences in the climatological partitioning between ice and liquid are estimated to contribute at least 20% to the intermodel spread in the high-latitude LWP response in the mixed-phase region poleward of 45°S. As a result, it is hypothesized that a more thorough evaluation and constraint of global <span class="hlt">climate</span> <span class="hlt">model</span> mixed-phase cloud parameterizations and validation of the total condensate and ice-liquid apportionment against observations will yield a substantial reduction in <span class="hlt">model</span> uncertainty in the high-latitude cloud response to warming.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS51A1975L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS51A1975L"><span>Tropical Atlantic Impacts on the Decadal <span class="hlt">Climate</span> Variability of the Tropical <span class="hlt">Ocean</span> and Atmosphere.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.</p> <p>2015-12-01</p> <p>Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian <span class="hlt">Ocean</span>. In particular, several recent works indicate that the Atlantic sea surface temperature (SST) may contribute to the <span class="hlt">climate</span> variability over the equatorial Pacific. Inspired by these studies, our work aims at investigating the impact of the tropical Atlantic on the entire tropical <span class="hlt">climate</span> system, and uncovering the physical dynamics under these tropical teleconnections. We first performed a 'pacemaker' simulation by restoring the satellite era tropical Atlantic SST changes in a fully coupled <span class="hlt">model</span> - the CESM1. Results reveal that the Atlantic warming heats the Indo-Western Pacific and cools the Eastern Pacific, enhances the Walker circulation and drives the subsurface Pacific to a La Niña mode, contributing to 60-70% of the above tropical changes in the past 30 years. The same pan-tropical teleconnections have been validated by the statistics of observations and 106 CMIP5 control simulations. We then used a hierarchy of atmospheric and <span class="hlt">oceanic</span> <span class="hlt">models</span> with different complexities, to single out the roles of atmospheric dynamics, atmosphere-<span class="hlt">ocean</span> fluxes, and <span class="hlt">oceanic</span> dynamics in these teleconnections. With these simulations we established a two-step mechanism as shown in the schematic figure: 1) Atlantic warming generates an atmospheric deep convection and induces easterly wind anomalies over the Indo-Western Pacific in the form of Kelvin waves, and westerly wind anomalies over the eastern equatorial Pacific as Rossby waves, in line with Gill's solution. This circulation changes warms the Indo-Western Pacific and cools the Eastern Pacific with the wind-evaporation-SST effect, forming a temperature gradient over the Indo-Pacific basins. 2) The temperature gradient further generates a secondary atmospheric deep convection, which reinforces the easterly wind anomalies over the equatorial Pacific and enhances the Walker circulation, triggering the Pacific to a La Ni</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.U35A..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.U35A..01C"><span>Atlantic <span class="hlt">Ocean</span> Circulation and <span class="hlt">Climate</span>: The Current View From the Geological Record</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Curry, W.</p> <p>2006-12-01</p> <p> <span class="hlt">climate</span> <span class="hlt">models</span>: variations in the temperature gradients in the Atlantic basin affect the position of the Intertropical Convergence Zone and alter evaporation and precipitation patterns in the tropics. The salinity anomalies caused by these atmospheric shifts eventually are transported back to high latitudes by <span class="hlt">ocean</span> circulation (Vellinga and Wu, 2004). Several recent geological reconstructions appear to observe such a coupling on centennial and millennial time scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GMD....10.3207S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GMD....10.3207S"><span>Practice and philosophy of <span class="hlt">climate</span> <span class="hlt">model</span> tuning across six US <span class="hlt">modeling</span> centers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Gavin A.; Bader, David; Donner, Leo J.; Elsaesser, Gregory S.; Golaz, Jean-Christophe; Hannay, Cecile; Molod, Andrea; Neale, Richard B.; Saha, Suranjana</p> <p>2017-09-01</p> <p><span class="hlt">Model</span> calibration (or <q>tuning</q>) is a necessary part of developing and testing coupled <span class="hlt">ocean</span>-atmosphere <span class="hlt">climate</span> <span class="hlt">models</span> regardless of their main scientific purpose. There is an increasing recognition that this process needs to become more transparent for both users of <span class="hlt">climate</span> <span class="hlt">model</span> output and other developers. Knowing how and why <span class="hlt">climate</span> <span class="hlt">models</span> are tuned and which targets are used is essential to avoiding possible misattributions of skillful predictions to data accommodation and vice versa. This paper describes the approach and practice of <span class="hlt">model</span> tuning for the six major US <span class="hlt">climate</span> <span class="hlt">modeling</span> centers. While details differ among groups in terms of scientific missions, tuning targets, and tunable parameters, there is a core commonality of approaches. However, practices differ significantly on some key aspects, in particular, in the use of initialized forecast analyses as a tool, the explicit use of the historical transient record, and the use of the present-day radiative imbalance vs. the implied balance in the preindustrial era as a target.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CliPa..12.2195G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CliPa..12.2195G"><span>Last Interglacial <span class="hlt">climate</span> and sea-level evolution from a coupled ice sheet-<span class="hlt">climate</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goelzer, Heiko; Huybrechts, Philippe; Loutre, Marie-France; Fichefet, Thierry</p> <p>2016-12-01</p> <p>As the most recent warm period in Earth's history with a sea-level stand higher than present, the Last Interglacial (LIG, ˜ 130 to 115 kyr BP) is often considered a prime example to study the impact of a warmer <span class="hlt">climate</span> on the two polar ice sheets remaining today. Here we simulate the Last Interglacial <span class="hlt">climate</span>, ice sheet, and sea-level evolution with the Earth system <span class="hlt">model</span> of intermediate complexity LOVECLIM v.1.3, which includes dynamic and fully coupled components representing the atmosphere, the <span class="hlt">ocean</span> and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. In this setup, sea-level evolution and <span class="hlt">climate</span>-ice sheet interactions are <span class="hlt">modelled</span> in a consistent framework.Surface mass balance change governed by changes in surface meltwater runoff is the dominant forcing for the Greenland ice sheet, which shows a peak sea-level contribution of 1.4 m at 123 kyr BP in the reference experiment. Our results indicate that ice sheet-<span class="hlt">climate</span> feedbacks play an important role to amplify <span class="hlt">climate</span> and sea-level changes in the Northern Hemisphere. The sensitivity of the Greenland ice sheet to surface temperature changes considerably increases when interactive albedo changes are considered. Southern Hemisphere polar and sub-polar <span class="hlt">ocean</span> warming is limited throughout the Last Interglacial, and surface and sub-shelf melting exerts only a minor control on the Antarctic sea-level contribution with a peak of 4.4 m at 125 kyr BP. Retreat of the Antarctic ice sheet at the onset of the LIG is mainly forced by rising sea level and to a lesser extent by reduced ice shelf viscosity as the surface temperature increases. Global sea level shows a peak of 5.3 m at 124.5 kyr BP, which includes a minor contribution of 0.35 m from <span class="hlt">oceanic</span> thermal expansion. Neither the individual contributions nor the total <span class="hlt">modelled</span> sea-level stand show fast multi-millennial timescale variations as indicated by some reconstructions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMPP33B1554R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMPP33B1554R"><span>An atmosphere-<span class="hlt">ocean</span> GCM <span class="hlt">modelling</span> study of the <span class="hlt">climate</span> response to changing Arctic seaways in the early Cenozoic.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberts, C. D.; Legrande, A. N.; Tripati, A. K.</p> <p>2008-12-01</p> <p>The report of fossil Azolla (a freshwater aquatic fern) in sediments from the Lomonosov Ridge suggests low salinity conditions occurred in the Arctic <span class="hlt">Ocean</span> in the early Eocene. Restricted passages between the Arctic <span class="hlt">Ocean</span> and the surrounding <span class="hlt">oceans</span> are hypothesized to have caused this Arctic freshening. We investigate this scenario using a water-isotope enabled atmosphere-<span class="hlt">ocean</span> general circulation <span class="hlt">model</span> with Eocene boundary conditions including 4xCO2, 7xCH4, altered bathymetry and topography, and an estimated distribution of Eocene vegetational types. In one experiment, <span class="hlt">oceanic</span> exchange between the Arctic <span class="hlt">Ocean</span> and other <span class="hlt">ocean</span> basins was restricted to two shallow (~250 m) seaways, one in the North Atlantic, the Greenland-Norwegian seaway, and the second connecting the Arctic <span class="hlt">Ocean</span> with the Tethys <span class="hlt">Ocean</span>, the Turgai Straits. In the restricted configuration, the Greenland-Norwegian seaway was closed and exchange through the Turgai Straits was limited to a depth of ~60 m. The simulations suggest that the severe restriction of Arctic seaways in the early Eocene may have been sufficient to freshen Arctic <span class="hlt">Ocean</span> surface waters, conducive to Azolla blooms. When exchange with the Arctic <span class="hlt">Ocean</span> is limited, salinities in the upper several hundred meters of the water column decrease by ~10 psu. In some regions, surface salinity is within 2-3 psu of the reported maximum modern conditions tolerated by Azolla (~5 psu). In the restricted scenario, salt is stored preferentially in the North Atlantic and Tethys <span class="hlt">oceans</span>, resulting in enhanced meridional overturning, increased poleward heat transport in the North Atlantic western boundary current, and warming of surface and intermediate waters in the North Atlantic by several degrees. Increased sensible and latent heat fluxes from the North Atlantic <span class="hlt">Ocean</span>, combined with a reduction in cloud albedo, also lead to an increase in surface air temperature of over much of North America, Greenland and Eurasia. Our work is consistent with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5474808','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5474808"><span>Postglacial response of Arctic <span class="hlt">Ocean</span> gas hydrates to <span class="hlt">climatic</span> amelioration</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Serov, Pavel; Mienert, Jürgen; Patton, Henry; Portnov, Alexey; Silyakova, Anna; Panieri, Giuliana; Carroll, Michael L.; Carroll, JoLynn; Andreassen, Karin; Hubbard, Alun</p> <p>2017-01-01</p> <p>Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic <span class="hlt">Ocean</span>. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic <span class="hlt">Ocean</span> bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt <span class="hlt">climate</span> change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate <span class="hlt">model</span>, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural <span class="hlt">climate</span> variability well before recent anthropogenic warming. PMID:28584081</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130001826','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130001826"><span>Upper-<span class="hlt">Ocean</span> Heat Balance Processes and the Walker Circulation in CMIP5 <span class="hlt">Model</span> Projections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robertson, F. R.; Roberts, J. B.; Funk, C.; Lyon, B.; Ricciardulli, L.</p> <p>2012-01-01</p> <p>Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical <span class="hlt">climate</span> system, and prospects for tropical <span class="hlt">climate</span> change in the face of anthropogenic forcing. Most contemporary <span class="hlt">climate</span> <span class="hlt">models</span> suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an <span class="hlt">ocean</span> dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a <span class="hlt">modeling</span> perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper <span class="hlt">ocean</span> heat content evolution in the WCRP CMIP5 <span class="hlt">model</span> projections. There is some diversity among <span class="hlt">model</span> simulations; for example, the CCSM4 indicates net <span class="hlt">ocean</span> warming over the IndoPacific region while the CSIRO <span class="hlt">model</span> concentrates separate warming responses over the central Pacific and Indian <span class="hlt">Ocean</span> regions. The <span class="hlt">models</span>, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among <span class="hlt">models</span> and, for <span class="hlt">models</span> as a whole, with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1200907','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1200907"><span>Impacts of <span class="hlt">ocean</span> albedo alteration on Arctic sea ice restoration and Northern Hemisphere <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.</p> <p></p> <p>The Arctic <span class="hlt">Ocean</span> is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude <span class="hlt">ocean</span> albedo could restore sea ice, but the <span class="hlt">climate</span> impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude <span class="hlt">ocean</span> albedo changes on Arctic sea ice restoration and <span class="hlt">climate</span>. In our simulated 4xCO₂ <span class="hlt">climate</span>, imposing surface albedo alterations over the Arctic <span class="hlt">Ocean</span> leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme <span class="hlt">ocean</span> albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter <span class="hlt">climate</span> outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although <span class="hlt">ocean</span> albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1200907-impacts-ocean-albedo-alteration-arctic-sea-ice-restoration-northern-hemisphere-climate','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1200907-impacts-ocean-albedo-alteration-arctic-sea-ice-restoration-northern-hemisphere-climate"><span>Impacts of <span class="hlt">ocean</span> albedo alteration on Arctic sea ice restoration and Northern Hemisphere <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.</p> <p>2015-04-01</p> <p>The Arctic <span class="hlt">Ocean</span> is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude <span class="hlt">ocean</span> albedo could restore sea ice, but the <span class="hlt">climate</span> impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude <span class="hlt">ocean</span> albedo changes on Arctic sea ice restoration and <span class="hlt">climate</span>. In our simulated 4xCO₂ <span class="hlt">climate</span>, imposing surface albedo alterations over the Arctic <span class="hlt">Ocean</span> leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme <span class="hlt">ocean</span> albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter <span class="hlt">climate</span> outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although <span class="hlt">ocean</span> albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ACP....17..595G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ACP....17..595G"><span>The G4Foam Experiment: global <span class="hlt">climate</span> impacts of regional <span class="hlt">ocean</span> albedo modification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gabriel, Corey J.; Robock, Alan; Xia, Lili; Zambri, Brian; Kravitz, Ben</p> <p>2017-01-01</p> <p>Reducing insolation has been proposed as a geoengineering response to global warming. Here we present the results of <span class="hlt">climate</span> <span class="hlt">model</span> simulations of a unique Geoengineering <span class="hlt">Model</span> Intercomparison Project Testbed experiment to investigate the benefits and risks of a scheme that would brighten certain <span class="hlt">oceanic</span> regions. The National Center for Atmospheric Research CESM CAM4-Chem global <span class="hlt">climate</span> <span class="hlt">model</span> was modified to simulate a scheme in which the albedo of the <span class="hlt">ocean</span> surface is increased over the subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere. In theory, this could be accomplished using a stable, nondispersive foam, comprised of tiny, highly reflective microbubbles. Such a foam has been developed under idealized conditions, although deployment at a large scale is presently infeasible. We conducted three ensemble members of a simulation (G4Foam) from 2020 through to 2069 in which the albedo of the <span class="hlt">ocean</span> surface is set to 0.15 (an increase of 150 %) over the three subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere, against a background of the RCP6.0 (representative concentration pathway resulting in +6 W m-2 radiative forcing by 2100) scenario. After 2069, geoengineering is ceased, and the simulation is run for an additional 20 years. Global mean surface temperature in G4Foam is 0.6 K lower than RCP6.0, with statistically significant cooling relative to RCP6.0 south of 30° N. There is an increase in rainfall over land, most pronouncedly in the tropics during the June-July-August season, relative to both G4SSA (specified stratospheric aerosols) and RCP6.0. Heavily populated and highly cultivated regions throughout the tropics, including the Sahel, southern Asia, the Maritime Continent, Central America, and much of the Amazon experience a statistically significant increase in precipitation minus evaporation. The temperature response to the relatively modest global average forcing of -1.5 W m-2 is amplified through a series of positive cloud feedbacks, in which more</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1349159','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1349159"><span>The G4Foam Experiment: Global <span class="hlt">climate</span> impacts of regional <span class="hlt">ocean</span> albedo modification</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gabriel, Corey J.; Robock, Alan; Xia, Lili</p> <p></p> <p>Reducing insolation has been proposed as a geoengineering response to global warming. Here we present the results of <span class="hlt">climate</span> <span class="hlt">model</span> simulations of a unique Geoengineering <span class="hlt">Model</span> Intercomparison Project Testbed experiment to investigate the benefits and risks of a scheme that would brighten certain <span class="hlt">oceanic</span> regions. The National Center for Atmospheric Research CESM CAM4-Chem global <span class="hlt">climate</span> <span class="hlt">model</span> was modified to simulate a scheme in which the albedo of the <span class="hlt">ocean</span> surface is increased over the subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere. In theory, this could be accomplished using a stable, nondispersive foam, comprised of tiny, highly reflective microbubbles. Such amore » foam has been developed under idealized conditions, although deployment at a large scale is presently infeasible. We conducted three ensemble members of a simulation (G4Foam) from 2020 through to 2069 in which the albedo of the <span class="hlt">ocean</span> surface is set to 0.15 (an increase of 150%) over the three subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere, against a background of the RCP6.0 (representative concentration pathway resulting in +6Wm -2 radiative forcing by 2100) scenario. After 2069, geoengineering is ceased, and the simulation is run for an additional 20 years. Global mean surface temperature in G4Foam is 0.6 K lower than RCP6.0, with statistically significant cooling relative to RCP6.0 south of 30°N. There is an increase in rainfall over land, most pronouncedly in the tropics during the June–July–August season, relative to both G4SSA (specified stratospheric aerosols) and RCP6.0. Heavily populated and highly cultivated regions throughout the tropics, including the Sahel, southern Asia, the Maritime Continent, Central America, and much of the Amazon experience a statistically significant increase in precipitation minus evaporation. The temperature response to the relatively modest global average forcing of -1.5 W m -2 is amplified through a series of positive cloud feedbacks, in which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1349159-g4foam-experiment-global-climate-impacts-regional-ocean-albedo-modification','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1349159-g4foam-experiment-global-climate-impacts-regional-ocean-albedo-modification"><span>The G4Foam Experiment: Global <span class="hlt">climate</span> impacts of regional <span class="hlt">ocean</span> albedo modification</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Gabriel, Corey J.; Robock, Alan; Xia, Lili; ...</p> <p>2017-01-12</p> <p>Reducing insolation has been proposed as a geoengineering response to global warming. Here we present the results of <span class="hlt">climate</span> <span class="hlt">model</span> simulations of a unique Geoengineering <span class="hlt">Model</span> Intercomparison Project Testbed experiment to investigate the benefits and risks of a scheme that would brighten certain <span class="hlt">oceanic</span> regions. The National Center for Atmospheric Research CESM CAM4-Chem global <span class="hlt">climate</span> <span class="hlt">model</span> was modified to simulate a scheme in which the albedo of the <span class="hlt">ocean</span> surface is increased over the subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere. In theory, this could be accomplished using a stable, nondispersive foam, comprised of tiny, highly reflective microbubbles. Such amore » foam has been developed under idealized conditions, although deployment at a large scale is presently infeasible. We conducted three ensemble members of a simulation (G4Foam) from 2020 through to 2069 in which the albedo of the <span class="hlt">ocean</span> surface is set to 0.15 (an increase of 150%) over the three subtropical <span class="hlt">ocean</span> gyres in the Southern Hemisphere, against a background of the RCP6.0 (representative concentration pathway resulting in +6Wm -2 radiative forcing by 2100) scenario. After 2069, geoengineering is ceased, and the simulation is run for an additional 20 years. Global mean surface temperature in G4Foam is 0.6 K lower than RCP6.0, with statistically significant cooling relative to RCP6.0 south of 30°N. There is an increase in rainfall over land, most pronouncedly in the tropics during the June–July–August season, relative to both G4SSA (specified stratospheric aerosols) and RCP6.0. Heavily populated and highly cultivated regions throughout the tropics, including the Sahel, southern Asia, the Maritime Continent, Central America, and much of the Amazon experience a statistically significant increase in precipitation minus evaporation. The temperature response to the relatively modest global average forcing of -1.5 W m -2 is amplified through a series of positive cloud feedbacks, in which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ESD.....9..285T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ESD.....9..285T"><span>Sensitivity of the tropical <span class="hlt">climate</span> to an interhemispheric thermal gradient: the role of tropical <span class="hlt">ocean</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Talento, Stefanie; Barreiro, Marcelo</p> <p>2018-03-01</p> <p>This study aims to determine the role of the tropical <span class="hlt">ocean</span> dynamics in the response of the <span class="hlt">climate</span> to extratropical thermal forcing. We analyse and compare the outcomes of coupling an atmospheric general circulation <span class="hlt">model</span> (AGCM) with two <span class="hlt">ocean</span> <span class="hlt">models</span> of different complexity. In the first configuration the AGCM is coupled with a slab <span class="hlt">ocean</span> <span class="hlt">model</span> while in the second a reduced gravity <span class="hlt">ocean</span> (RGO) <span class="hlt">model</span> is additionally coupled in the tropical region. We find that the imposition of extratropical thermal forcing (warming in the Northern Hemisphere and cooling in the Southern Hemisphere with zero global mean) produces, in terms of annual means, a weaker response when the RGO is coupled, thus indicating that the tropical <span class="hlt">ocean</span> dynamics oppose the incoming remote signal. On the other hand, while the slab <span class="hlt">ocean</span> coupling does not produce significant changes to the equatorial Pacific sea surface temperature (SST) seasonal cycle, the RGO configuration generates strong warming in the central-eastern basin from April to August balanced by cooling during the rest of the year, strengthening the seasonal cycle in the eastern portion of the basin. We hypothesize that such changes are possible via the dynamical effect that zonal wind stress has on the thermocline depth. We also find that the imposed extratropical pattern affects El Niño-Southern Oscillation, weakening its amplitude and low-frequency behaviour.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP41E..08T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP41E..08T"><span>140-year subantarctic tree-ring temperature reconstruction reveals tropical forcing of increased Southern <span class="hlt">Ocean</span> <span class="hlt">climate</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turney, C. S.; Fogwill, C. J.; Palmer, J. G.; VanSebille, E.; Thomas, Z.; McGlone, M.; Richardson, S.; Wilmshurst, J.; Fenwick, P.; Zunz, V.; Goosse, H.; Wilson, K. J.; Carter, L.; Lipson, M.; Jones, R. T.; Harsch, M.; Clark, G.; Marzinelli, E.; Rogers, T.; Rainsley, E.; Ciasto, L.; Waterman, S.; Thomas, E. R.; Visbeck, M.</p> <p>2017-12-01</p> <p>Occupying about 14 % of the world's surface, the Southern <span class="hlt">Ocean</span> plays a fundamental role in <span class="hlt">ocean</span> and atmosphere circulation, carbon cycling and Antarctic ice-sheet dynamics. Unfortunately, high interannual variability and a dearth of instrumental observations before the 1950s limits our understanding of how marine-atmosphere-ice domains interact on multi-decadal timescales and the impact of anthropogenic forcing. Here we integrate <span class="hlt">climate</span>-sensitive tree growth with <span class="hlt">ocean</span> and atmospheric observations on south-west Pacific subantarctic islands that lie at the boundary of polar and subtropical <span class="hlt">climates</span> (52-54˚S). Our annually resolved temperature reconstruction captures regional change since the 1870s and demonstrates a significant increase in variability from the 1940s, a phenomenon predating the observational record, and coincident with major changes in mammalian and bird populations. <span class="hlt">Climate</span> reanalysis and <span class="hlt">modelling</span> show a parallel change in tropical Pacific sea surface temperatures that generate an atmospheric Rossby wave train which propagates across a large part of the Southern Hemisphere during the austral spring and summer. Our results suggest that modern observed high interannual variability was established across the mid-twentieth century, and that the influence of contemporary equatorial Pacific temperatures may now be a permanent feature across the mid- to high latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...47..211T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...47..211T"><span><span class="hlt">Oceanic</span> influence on the precipitation in Venezuela under current and future <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tim, Nele; Bravo de Guenni, Lelys</p> <p>2016-07-01</p> <p>The Pacific and Atlantic <span class="hlt">oceanic</span> influences on observational rainfall data from weather stations over Venezuela are analyzed using Canonical Correlation Analysis (CCA) executed in the <span class="hlt">Climate</span> Predictability Tool. CCA is further conducted on rainfall and sea surface temperature data obtained from the Max Planck Institute for Meteorology Earth System <span class="hlt">Model</span> (MPI-ESM) for historical (1951-2010) and future (2041-2100) periods. Four <span class="hlt">oceanic</span> regions (North Tropical Atlantic, Niño3, Niño3.4 and an area which includes all previous three) are used for the CCA using data from the Extended Reconstructed Sea Surface Temperature (ERSST) data set, while precipitation data from two regions: a coastal region and an inland region are used in the analysis. Venezuelan seasons (dry and wet) were separated into an early and a late period. The <span class="hlt">oceanic</span> impact on the precipitation of the station data is, in the majority of the cases, higher in the inland than at the coast. The Pacific's influence is stronger in the early dry season than in the wet season, whereas the Atlantic's influence is stronger in the wet season (inland). In contrast, CCA applied to the <span class="hlt">model</span> data provides highest correlation coefficients in the late wet season for all <span class="hlt">oceanic</span> regions. In most cases the North Tropical Atlantic has a stronger influence than the Niño regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1010911','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1010911"><span>Final Technical Report for "Collaborative Research: Regional <span class="hlt">climate</span>-change projections through next-generation empirical and dynamical <span class="hlt">models</span>"</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robertson, A.W.; Ghil, M.; Kravtsov, K.</p> <p>2011-04-08</p> <p>This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov <span class="hlt">models</span> (NHMMs) and coupled <span class="hlt">ocean</span>-atmosphere (O-A) intermediate-complexity <span class="hlt">models</span> (ICMs) to identify the potentially predictable modes of <span class="hlt">climate</span> variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) <span class="hlt">models</span> for gaining insight into the underlying dynamics in observational data and general circulation <span class="hlt">model</span> (GCM) simulations. Using coupled O-A ICMs,more » we have identified a new mechanism of interdecadal <span class="hlt">climate</span> variability, involving the midlatitude <span class="hlt">oceans</span> mesoscale eddy field and nonlinear, persistent atmospheric response to the <span class="hlt">oceanic</span> anomalies. A related decadal mode is also identified, associated with the <span class="hlt">oceans</span> thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR <span class="hlt">model</span> developments and software to strengthen two key pillars of support for the development and application of <span class="hlt">climate</span> <span class="hlt">models</span> for <span class="hlt">climate</span> change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from <span class="hlt">climate</span> <span class="hlt">models</span> to applications, in order to inform societal adaptation strategies to <span class="hlt">climate</span> change at the regional scale, including <span class="hlt">model</span> calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-<span class="hlt">model</span> ensembles. Our main results from the grant consist of extensive further development of the hidden Markov <span class="hlt">models</span> for rainfall simulation and downscaling specifically within the non-stationary <span class="hlt">climate</span> change context together with the development of parallelized software; application of NHMMs to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1010914','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1010914"><span>Final Technical Report for "Collaborative Research. Regional <span class="hlt">climate</span>-change projections through next-generation empirical and dynamical <span class="hlt">models</span>"</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kravtsov, S.; Robertson, Andrew W.; Ghil, Michael</p> <p>2011-04-08</p> <p>This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov <span class="hlt">models</span> (NHMMs) and coupled <span class="hlt">ocean</span>-atmosphere (O-A) intermediate-complexity <span class="hlt">models</span> (ICMs) to identify the potentially predictable modes of <span class="hlt">climate</span> variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) <span class="hlt">models</span> for gaining insight into the underlying dynamics in observational data and general circulation <span class="hlt">model</span> (GCM) simulations. Using coupled O-A ICMs,more » we have identified a new mechanism of interdecadal <span class="hlt">climate</span> variability, involving the midlatitude <span class="hlt">oceans</span> mesoscale eddy field and nonlinear, persistent atmospheric response to the <span class="hlt">oceanic</span> anomalies. A related decadal mode is also identified, associated with the <span class="hlt">oceans</span> thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR <span class="hlt">model</span> developments and software to strengthen two key pillars of support for the development and application of <span class="hlt">climate</span> <span class="hlt">models</span> for <span class="hlt">climate</span> change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from <span class="hlt">climate</span> <span class="hlt">models</span> to applications, in order to inform societal adaptation strategies to <span class="hlt">climate</span> change at the regional scale, including <span class="hlt">model</span> calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-<span class="hlt">model</span> ensembles. Our main results from the grant consist of extensive further development of the hidden Markov <span class="hlt">models</span> for rainfall simulation and downscaling specifically within the non-stationary <span class="hlt">climate</span> change context together with the development of parallelized software; application of NHMMs to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9681S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9681S"><span>Seasonal re-emergence of North Atlantic subsurface <span class="hlt">ocean</span> temperature anomalies and Northern hemisphere <span class="hlt">climate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sinha, Bablu; Blaker, Adam; Duchez, Aurelie; Grist, Jeremy; Hewitt, Helene; Hirschi, Joel; Hyder, Patrick; Josey, Simon; Maclachlan, Craig; New, Adrian</p> <p>2017-04-01</p> <p>A high-resolution coupled <span class="hlt">ocean</span> atmosphere <span class="hlt">model</span> is used to study the effects of seasonal re-emergence of North Atlantic subsurface <span class="hlt">ocean</span> temperature anomalies on northern hemisphere winter <span class="hlt">climate</spa