Science.gov

Sample records for global ocean storage

  1. Global Ocean Storage of Anthropogenic Carbon (GOSAC)

    SciTech Connect

    Orr, J C

    2002-04-02

    GOSAC was an EC-funded project (1998-2001) focused on improving the predictive capacity and accelerating development of global-scale, three-dimensional, ocean carbon-cycle models by means of standardized model evaluation and model intercomparison. Through the EC Environment and Climate Programme, GOSAC supported the participation of seven European modeling groups in the second phase of the larger international effort OCMIP (the Ocean Carbon-Cycle Model Intercomparison Project). OCMIP included model comparison and validation for both CO{sub 2} and other ocean circulation and biogeochemical tracers. Beyond the international OCMIP effort, GOSAC also supported the same EC ocean carbon cycle modeling groups to make simulations to evaluate the efficiency of purposeful sequestration of CO{sub 2} in the ocean. Such sequestration, below the thermocline has been proposed as a strategy to help mitigate the increase of CO{sub 2} in the atmosphere. Some technical and scientific highlights of GOSAC are given.

  2. Global upper ocean heat storage response to radiative forcing from changing solar irradiance and increasing greenhouse gas/aerosol concentrations

    NASA Astrophysics Data System (ADS)

    White, Warren B.; Cayan, Daniel R.; Lean, Judith

    1998-09-01

    We constructed gridded fields of diabatic heat storage changes in the upper ocean from 20°S to 60°N from historical temperature profiles collected from 1955 to 1996. We filtered these 42 year records for periods of 8 to 15 years and 15 to 30 years, producing depth-weighted vertical average temperature (DVT) changes from the sea surface to the top of the main pycnocline. Basin and global averages of these DVT changes reveal decadal and interdecadal variability in phase across the Indian, Pacific, Atlantic, and Global Oceans, each significantly correlated with changing surface solar radiative forcing at a lag of 0+/-2 years. Decadal and interdecadal changes in global average DVT are 0.06°+/-0.01°K and 0.04°K+/-0.01°K, respectively, the same as those expected from consideration of the Stefan-Boltzmann radiation balance (i.e., 0.3°K per Wm-2) in response to 0.1% changes in surface solar radiative forcing of 0.2 Wm-2 and 0.15 Wm-2, respectively. Global spatial patterns of DVT changes are similar to temperature changes simulated in coupled ocean-atmosphere models, suggesting that natural modes of Earth's variability are phase-locked to the solar irradiance cycle. A trend in global average DVT of 0.15°K over this 42 year record cannot be explained by changing surface solar radiative forcing. But when we consider the 0.5 Wm-2 increase in surface radiative forcing estimated from the increase in atmospheric greenhouse gas and aerosol (GGA) concentrations over this period [Intergovernmental Panel on Climate Change, 1995], the Stefan-Boltzmann radiation balance yields this observed change. Moreover, the sum of solar and GGA surface radiative forcing can explain the relatively sharp increase in global and basin average DVT in the late 1970's.

  3. Microbial Carbon Pump ---A New Mechanism for Long-Term Carbon Storage in the Global Ocean (Invited)

    NASA Astrophysics Data System (ADS)

    Jiao, N.; Azam, F.; McP Working Group; Scor Wg134

    2010-12-01

    to a recalcitrant carbon reservoir, pumping organic carbon from low concentrations of labile DOM to high concentrations of recalcitrant DOM, building up a huge reservoir for carbon storage over time. Meanwhile the MCP transfers more carbon relative to nitrogen and phosphorus from the reactive organic matter pool into recalcitrant organic matter pool. Compared with the solubility pump, an abiotic mechanism for carbon storage in the ocean which has ocean acidification impacts on marine organisms and biogeochemical cycles, the MCP-driven recalcitrant DOM carbon storage does not appreciably alter the buffering capacity of seawater and has no known negative impact on marine organisms. Furthermore, in the ocean warming scenario, the partitioning of biogenic carbon flow will change, with the flow to POM diminishing and that to DOM increasing, and thus the role of the MCP in carbon storage will most likely enhanced. A working group joined by 26 scientists from 12 countries has been formed under the Scientific Committee for Oceanic Research (SCOR-WG134) to address this multi-faceted biogeochemical issue related to carbon cycling in the ocean and global climate changes.

  4. Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2013-01-01

    Phytoplankton are free-floating algae that grow in the euphotic zone of the upper ocean, converting carbon dioxide, sunlight, and available nutrients into organic carbon through photosynthesis. Despite their microscopic size, these photoautotrophs are responsible for roughly half the net primary production on Earth (NPP; gross primary production minus respiration), fixing atmospheric CO2 into food that fuels our global ocean ecosystems. Phytoplankton thus play a critical role in the global carbon cycle, and their growth patterns are highly sensitive to environmental changes such as increased ocean temperatures that stratify the water column and prohibit the transfer of cold, nutrient richwaters to the upper ocean euphotic zone.

  5. Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2014-01-01

    Marine phytoplankton are responsible for roughly half the net primary production (NPP) on Earth, fixing atmospheric CO2 into food that fuels global ocean ecosystems and drives the ocean's biogeochemical cycles. Phytoplankton growth is highly sensitive to variations in ocean physical properties, such as upper ocean stratification and light availability within this mixed layer. Satellite ocean color sensors, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; McClain 2009) and Moderate Resolution Imaging Spectroradiometer (MODIS; Esaias 1998), provide observations of sufficient frequency and geographic coverage to globally monitor physically-driven changes in phytoplankton distributions. In practice, ocean color sensors retrieve the spectral distribution of visible solar radiation reflected upward from beneath the ocean surface, which can then be related to changes in the photosynthetic phytoplankton pigment, chlorophyll- a (Chla; measured in mg m-3). Here, global Chla data for 2013 are evaluated within the context of the 16-year continuous record provided through the combined observations of SeaWiFS (1997-2010) and MODIS on Aqua (MODISA; 2002-present). Ocean color measurements from the recently launched Visible and Infrared Imaging Radiometer Suite (VIIRS; 2011-present) are also considered, but results suggest that the temporal calibration of the VIIRS sensor is not yet sufficiently stable for quantitative global change studies. All MODISA (version 2013.1), SeaWiFS (version 2010.0), and VIIRS (version 2013.1) data presented here were produced by NASA using consistent Chla algorithms.

  6. Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2014-01-01

    Marine phytoplankton are responsible for roughly half the net primary production (NPP) on Earth, fixing atmospheric CO2 into food that fuels global ocean ecosystems and drives the ocean's biogeochemical cycles. Phytoplankton growth is highly sensitive to variations in ocean physical properties, such as upper ocean stratification and light availability within this mixed layer. Satellite ocean color sensors, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; McClain 2009) and Moderate Resolution Imaging Spectroradiometer (MODIS; Esaias 1998), provide observations of sufficient frequency and geographic coverage to globally monitor physically-driven changes in phytoplankton distributions. In practice, ocean color sensors retrieve the spectral distribution of visible solar radiation reflected upward from beneath the ocean surface, which can then be related to changes in the photosynthetic phytoplankton pigment, chlorophyll- a (Chla; measured in mg m-3). Here, global Chla data for 2013 are evaluated within the context of the 16-year continuous record provided through the combined observations of SeaWiFS (1997-2010) and MODIS on Aqua (MODISA; 2002-present). Ocean color measurements from the recently launched Visible and Infrared Imaging Radiometer Suite (VIIRS; 2011-present) are also considered, but results suggest that the temporal calibration of the VIIRS sensor is not yet sufficiently stable for quantitative global change studies. All MODISA (version 2013.1), SeaWiFS (version 2010.0), and VIIRS (version 2013.1) data presented here were produced by NASA using consistent Chla algorithms.

  7. The effect of ocean acidification on carbon storage and sequestration in seagrass beds; a global and UK context.

    PubMed

    Garrard, Samantha L; Beaumont, Nicola J

    2014-09-15

    Ocean acidification will have many negative consequences for marine organisms and ecosystems, leading to a decline in many ecosystem services provided by the marine environment. This study reviews the effect of ocean acidification (OA) on seagrasses, assessing how this may affect their capacity to sequester carbon in the future and providing an economic valuation of these changes. If ocean acidification leads to a significant increase in above- and below-ground biomass, the capacity of seagrass to sequester carbon will be significantly increased. The associated value of this increase in sequestration capacity is approximately £500 and 600 billion globally between 2010 and 2100. A proportionally similar increase in carbon sequestration value was found for the UK. This study highlights one of the few positive stories for ocean acidification and underlines that sustainable management of seagrasses is critical to avoid their continued degradation and loss of carbon sequestration capacity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

    NASA Astrophysics Data System (ADS)

    Carmack, E. C.; Yamamoto-Kawai, M.; Haine, T. W. N.; Bacon, S.; Bluhm, B. A.; Lique, C.; Melling, H.; Polyakov, I. V.; Straneo, F.; Timmermans, M.-L.; Williams, W. J.

    2016-03-01

    The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean's thermohaline circulation. We here assess the system's key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and storage) of freshwater components within the Arctic Ocean; and (3) the release and export of freshwater components into the bordering convective domains of the North Atlantic. We then examine physical, chemical, or biological processes which are influenced or constrained by the local quantities and geochemical qualities of freshwater; these include stratification and vertical mixing, ocean heat flux, nutrient supply, primary production, ocean acidification, and biogeochemical cycling. Internal to the Arctic the joint effects of sea ice decline and hydrological cycle intensification have strengthened coupling between the ocean and the atmosphere (e.g., wind and ice drift stresses, solar radiation, and heat and moisture exchange), the bordering drainage basins (e.g., river discharge, sediment transport, and erosion), and terrestrial ecosystems (e.g., Arctic greening, dissolved and particulate carbon loading, and altered phenology of biotic components). External to the Arctic freshwater export acts as both a constraint to and a necessary ingredient for deep convection in the bordering subarctic gyres and thus affects the global thermohaline circulation. Geochemical fingerprints attained within the Arctic Ocean are likewise exported into the neighboring subarctic systems and beyond. Finally, we discuss observed and modeled functions and changes in this system on seasonal, annual, and decadal time scales and discuss mechanisms that link the marine system to atmospheric, terrestrial, and cryospheric systems.

  9. Global Ocean Currents Database

    NASA Astrophysics Data System (ADS)

    Boyer, T.; Sun, L.

    2016-02-01

    The NOAA's National Centers for Environmental Information has released an ocean currents database portal that aims 1) to integrate global ocean currents observations from a variety of instruments with different resolution, accuracy and response to spatial and temporal variability into a uniform network common data form (NetCDF) format and 2) to provide a dedicated online data discovery, access to NCEI-hosted and distributed data sources for ocean currents data. The portal provides a tailored web application that allows users to search for ocean currents data by platform types and spatial/temporal ranges of their interest. The dedicated web application is available at http://www.nodc.noaa.gov/gocd/index.html. The NetCDF format supports widely-used data access protocols and catalog services such as OPeNDAP (Open-source Project for a Network Data Access Protocol) and THREDDS (Thematic Real-time Environmental Distributed Data Services), which the GOCD users can use data files with their favorite analysis and visualization client software without downloading to their local machine. The potential users of the ocean currents database include, but are not limited to, 1) ocean modelers for their model skills assessments, 2) scientists and researchers for studying the impact of ocean circulations on the climate variability, 3) ocean shipping industry for safety navigation and finding optimal routes for ship fuel efficiency, 4) ocean resources managers while planning for the optimal sites for wastes and sewages dumping and for renewable hydro-kinematic energy, and 5) state and federal governments to provide historical (analyzed) ocean circulations as an aid for search and rescue

  10. Deepwater carbonate ion concentrations in the western tropical Pacific since 250 ka: Evidence for oceanic carbon storage and global climate influence

    NASA Astrophysics Data System (ADS)

    Qin, Bingbin; Li, Tiegang; Xiong, Zhifang; Algeo, Thomas J.; Chang, Fengming

    2017-04-01

    We present new "size-normalized weight" (SNW)-Δ[CO32-] core-top calibrations for three planktonic foraminiferal species and assess their reliability as a paleo-alkalinity proxy. SNWs of Globigerina sacculifer and Neogloboquadrina dutertrei can be used to reconstruct past deep Pacific [CO32-], whereas SNWs of Pulleniatina obliquiloculata are controlled by additional environmental factors. Based on this methodological advance, we reconstruct SNW-based deepwater [CO32-] for core WP7 from the western tropical Pacific since 250 ka. Secular variation in the SNW proxy documents little change in deep Pacific [CO32-] between the Last Glacial Maximum and the Holocene. Further back in time, deepwater [CO32-] shows long-term increases from marine isotope stage (MIS) 5e to MIS 3 and from early MIS 7 to late MIS 6, consistent with the "coral reef hypothesis" that the deep Pacific Ocean carbonate system responded to declining shelf carbonate production during these two intervals. During deglaciations, we have evidence of [CO32-] peaks coincident with Terminations 2 and 3, which suggests that a breakdown of oceanic vertical stratification drove a net transfer of CO2 from the ocean to the atmosphere, causing spikes in carbonate preservation (i.e., the "deglacial ventilation hypothesis"). During MIS 4, a transient decline in SNW-based [CO32-], along with other reported [CO32-] and/or dissolution records, implies that increased deep-ocean carbon storage resulted in a global carbonate dissolution event. These findings provide new insights into the role of the deep Pacific in the global carbon cycle during the late Quaternary.

  11. Two decades of Pacific anthropogenic carbon storage and ocean acidification along Global Ocean Ship-based Hydrographic Investigations Program sections P16 and P02

    NASA Astrophysics Data System (ADS)

    Carter, B. R.; Feely, R. A.; Mecking, S.; Cross, J. N.; Macdonald, A. M.; Siedlecki, S. A.; Talley, L. D.; Sabine, C. L.; Millero, F. J.; Swift, J. H.; Dickson, A. G.; Rodgers, K. B.

    2017-02-01

    A modified version of the extended multiple linear regression (eMLR) method is used to estimate anthropogenic carbon concentration (Canth) changes along the Pacific P02 and P16 hydrographic sections over the past two decades. P02 is a zonal section crossing the North Pacific at 30°N, and P16 is a meridional section crossing the North and South Pacific at 150°W. The eMLR modifications allow the uncertainties associated with choices of regression parameters to be both resolved and reduced. Canth is found to have increased throughout the water column from the surface to 1000 m depth along both lines in both decades. Mean column Canth inventory increased consistently during the earlier (1990s-2000s) and recent (2000s-2010s) decades along P02, at rates of 0.53 ± 0.11 and 0.46 ± 0.11 mol C m-2 a-1, respectively. By contrast, Canth storage accelerated from 0.29 ± 0.10 to 0.45 ± 0.11 mol C m-2 a-1 along P16. Shifts in water mass distributions are ruled out as a potential cause of this increase, which is instead attributed to recent increases in the ventilation of the South Pacific Subtropical Cell. Decadal changes along P16 are extrapolated across the gyre to estimate a Pacific Basin average storage between 60°S and 60°N of 6.1 ± 1.5 PgC decade-1 in the earlier decade and 8.8 ± 2.2 PgC decade-1 in the recent decade. This storage estimate is large despite the shallow Pacific Canth penetration due to the large volume of the Pacific Ocean. By 2014, Canth storage had changed Pacific surface seawater pH by -0.08 to -0.14 and aragonite saturation state by -0.57 to -0.82.

  12. Ensemble global ocean forecasting

    NASA Astrophysics Data System (ADS)

    Brassington, G. B.

    2016-02-01

    A novel time-lagged ensemble system based on multiple independent cycles has been performed in operations at the Australian Bureau of Meteorology for the past 3 years. Despite the use of only four cycles the ensemble mean provided robustly higher skill and the ensemble variance was a reliable predictor of forecast errors. A spectral analysis comparing the ensemble mean with the members demonstrated the gradual increase in power of random errors with wavenumber up to a saturation length scale imposed by the resolution of the observing system. This system has been upgraded to a near-global 0.1 degree system in a new hybrid six-member ensemble system configuration including a new data assimilation system, cycling pattern and initialisation. The hybrid system consists of two ensemble members per day each with a 3 day cycle. We will outline the performance of both the deterministic and ensemble ocean forecast system.

  13. The Global Ocean Observing System

    NASA Technical Reports Server (NTRS)

    Kester, Dana

    1992-01-01

    A Global Ocean Observing System (GOOS) should be established now with international coordination (1) to address issues of global change, (2) to implement operational ENSO forecasts, (3) to provide the data required to apply global ocean circulation models, and (4) to extract the greatest value from the one billion dollar investment over the next ten years in ocean remote sensing by the world's space agencies. The objectives of GOOS will focus on climatic and oceanic predictions, on assessing coastal pollution, and in determining the sustainability of living marine resources and ecosystems. GOOS will be a complete system including satellite observations, in situ observations, numerical modeling of ocean processes, and data exchange and management. A series of practical and economic benefits will be derived from the information generated by GOOS. In addition to the marine science community, these benefits will be realized by the energy industries of the world, and by the world's fisheries. The basic oceanic variables that are required to meet the oceanic and predictability objectives of GOOS include wind velocity over the ocean, sea surface temperature and salinity, oceanic profiles of temperature and salinity, surface current, sea level, the extent and thickness of sea ice, the partial pressure of CO2 in surface waters, and the chlorophyll concentration of surface waters. Ocean circulation models and coupled ocean-atmosphere models can be used to evaluate observing system design, to assimilate diverse data sets from in situ and remotely sensed observations, and ultimately to predict future states of the system. The volume of ocean data will increase enormously over the next decade as new satellite systems are launched and as complementary in situ measuring systems are deployed. These data must be transmitted, quality controlled, exchanged, analyzed, and archived with the best state-of-the-art computational methods.

  14. The Global Ocean Observing System

    NASA Technical Reports Server (NTRS)

    Kester, Dana

    1992-01-01

    A Global Ocean Observing System (GOOS) should be established now with international coordination (1) to address issues of global change, (2) to implement operational ENSO forecasts, (3) to provide the data required to apply global ocean circulation models, and (4) to extract the greatest value from the one billion dollar investment over the next ten years in ocean remote sensing by the world's space agencies. The objectives of GOOS will focus on climatic and oceanic predictions, on assessing coastal pollution, and in determining the sustainability of living marine resources and ecosystems. GOOS will be a complete system including satellite observations, in situ observations, numerical modeling of ocean processes, and data exchange and management. A series of practical and economic benefits will be derived from the information generated by GOOS. In addition to the marine science community, these benefits will be realized by the energy industries of the world, and by the world's fisheries. The basic oceanic variables that are required to meet the oceanic and predictability objectives of GOOS include wind velocity over the ocean, sea surface temperature and salinity, oceanic profiles of temperature and salinity, surface current, sea level, the extent and thickness of sea ice, the partial pressure of CO2 in surface waters, and the chlorophyll concentration of surface waters. Ocean circulation models and coupled ocean-atmosphere models can be used to evaluate observing system design, to assimilate diverse data sets from in situ and remotely sensed observations, and ultimately to predict future states of the system. The volume of ocean data will increase enormously over the next decade as new satellite systems are launched and as complementary in situ measuring systems are deployed. These data must be transmitted, quality controlled, exchanged, analyzed, and archived with the best state-of-the-art computational methods.

  15. Is Ocean Heat Storage Presently Knowable?

    NASA Astrophysics Data System (ADS)

    Rogers, N. L.

    2012-12-01

    Ocean heat storage plays a key role in predictions of global warming. The oceans' great thermal inertia moderates any radiative energy imbalance. A number of authors have suggested that most ocean heat storage takes place in the upper 700 meters. With the deployment of the Argo system in 2003 and the subsequent failure to detect the expected ocean warming investigators started to look deeper, down to 2000 meters. A mostly ignored problem with using ocean heat below the tropical/ temperate thermocline to measure current energy imbalances is that, as revealed by tracer studies, below thermocline water is old water that has not been in good thermal communication with the atmosphere for hundreds of years. The thermocline can be thought of as a collision between the mixed layer and very old and cold water that is rising from the abyss in an elevator-like fashion, at a rate that is uncertain but perhaps a few meters per year. The elevator is driven by dense water that, in the polar regions sinks into the abyss. A slow downward flow of heat from vertical mixing, driven by currents and tides, warms the bottom water, thus making room for new, denser, bottom water. It is helpful, as a thinking aid, to divide the Earth into the surface realm, consisting of the atmosphere and upper layer of the oceans and a second realm consisting of the deep ocean. The deep ocean may as well be in outer space since it is thermally isolated from the Earth's climate except for a very slow and presumed constant seepage of heat. Between the two realms are transition regions, the polar sinking regions and the thermocline upwelling regions. Cold water sinking warms the surface because we have removed water colder than the Earth's average temperature of 15 C from the surface realm. Upwelling cools the surface because we add water colder than the average temperature to the surface realm. The sinking and upwelling flows are equal but variable. If we draw a line at 2000 meters we can hope that the

  16. Ecosystem and Societal Consequences of Ocean versus Atmosphere Carbon Storage

    NASA Astrophysics Data System (ADS)

    Barry, J. P.; Adams, E. E.; Bleck, R.; Caldeira, K.; Carman, K.; Erickson, D.; Kennett, J. P.; Sarmiento, J. L.; Tsouris, C.

    2005-12-01

    Climate stabilization during the next 100 to 200 y will require significant reductions in atmospheric carbon dioxide emissions to avoid large increases in global temperature. While there is only mild disagreement concerning carbon management options such as energy efficiency, alternative energy sources, and even geologic C storage, ocean storage remains controversial, due to its potential impacts for deep-sea ecosystems. A cautionary approach to carbon management might avoid any ocean C storage. However, this approach does not consider the balance between ocean and terrestrial ecosystems, or societal concerns. Using a broader perspective, we might ask whether atmospheric CO2 storage (i.e. the status quo), or deep ocean sequestration is better for Earth's ecosystems and societies? We explored the potential storage capacity of the deep ocean for carbon dioxide, under scenarios producing a 0.2 pH unit reduction, a level similar to observed scale of pH variability in deep ocean basins, which may also represent coarse thresholds for deep-sea ecosystem impacts. Roughly 500 PgC could be stored in the deep ocean to lower pH by 0.2 units, yielding a long term (~250 y) ocean sequestration program of 2 PgCy-1. The mitigation value of such ocean C sequestration for upper ocean and terrestrial systems depends strongly on future emission scenarios. Under a low emission scenario (e.g. SRES scenario A1T, B1; atm CO2 ~575 ppm, global temperature change of ~+2 oC), a 2 PgCy-1 ocean CO2 injection program could mitigate global temperature by ~-0.4 oC (20%) by 2100. This could reduce significantly the number of people at risk of water shortage and tropical diseases, with lesser improvement expected for hunger or coastal flooding. Mitigation for terrestrial and shallow ocean ecosystems is difficult to predict. A 0.4 oC reduction in warming this century is expected to delay the progression of coral reef devastation by roughly 20 y. The mitigation potential of ocean storage under very

  17. The global ocean microbiome.

    PubMed

    Moran, Mary Ann

    2015-12-11

    The microbiome of the largest environment on Earth has been gradually revealing its secrets over four decades of study. Despite the dispersed nature of substrates and the transience of surfaces, marine microbes drive essential transformations in all global elemental cycles. Much has been learned about the microbes that carry out key biogeochemical processes, but there are still plenty of ambiguities about the factors important in regulating activity, including the role of microbial interactions. Identifying the molecular "currencies" exchanged within the microbial community will provide key information on microbiome function and its vulnerability to environmental change. Copyright © 2015, American Association for the Advancement of Science.

  18. Simulating PACE Global Ocean Radiances

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Rousseaux, Cecile S.

    2017-01-01

    The NASA PACE mission is a hyper-spectral radiometer planned for launch in the next decade. It is intended to provide new information on ocean biogeochemical constituents by parsing the details of high resolution spectral absorption and scattering. It is the first of its kind for global applications and as such, poses challenges for design and operation. To support pre-launch mission development and assess on-orbit capabilities, the NASA Global Modeling and Assimilation Office has developed a dynamic simulation of global water-leaving radiances, using an ocean model containing multiple ocean phytoplankton groups, particulate detritus, particulate inorganic carbon (PIC), and chromophoric dissolved organic carbon (CDOC) along with optical absorption and scattering processes at 1 nm spectral resolution. The purpose here is to assess the skill of the dynamic model and derived global radiances. Global bias, uncertainty, and correlation are derived using available modern satellite radiances at moderate spectral resolution. Total chlorophyll, PIC, and the absorption coefficient of CDOC (aCDOC), are simultaneously assimilated to improve the fidelity of the optical constituent fields. A 5-year simulation showed statistically significant (P < 0.05) comparisons of chlorophyll (r = 0.869), PIC (r = 0.868), and a CDOC (r =0.890) with satellite data. Additionally, diatoms (r = 0.890), cyanobacteria (r = 0.732), and coccolithophores (r = 0.716) were significantly correlated with in situ data. Global assimilated distributions of optical constituents were coupled with a radiative transfer model (Ocean-Atmosphere Spectral Irradiance Model, OASIM) to estimate normalized water-leaving radiances at 1 nm for the spectral range 250-800 nm. These unassimilated radiances were within 0.074 mW/sq cm/micron/sr of MODIS-Aqua radiances at 412, 443, 488, 531, 547, and 667 nm. This difference represented a bias of 10.4% (model low). A mean correlation of 0.706 (P < 0.05) was found with global

  19. Global Trends in Ocean Noise.

    PubMed

    Miksis-Olds, Jennifer L

    2016-01-01

    This ongoing work provides information about sound level trends from three ocean regions to compare with those of the North Pacific to determine whether increasing sound levels are a global phenomenon. Here the term soundscape is used to describe a measured physical property that can be selectively decomposed by frequency and sound level is used to provide insight relating to conditions ranging from the quietest conditions (sound floor) to the most extreme acoustic events. Acoustic time series from the Indian, South Atlantic, and Equatorial Pacific Oceans were used to quantify the rate and direction of low-frequency change over the past decade.

  20. Modelling the global coastal ocean.

    PubMed

    Holt, Jason; Harle, James; Proctor, Roger; Michel, Sylvain; Ashworth, Mike; Batstone, Crispian; Allen, Icarus; Holmes, Robert; Smyth, Tim; Haines, Keith; Bretherton, Dan; Smith, Gregory

    2009-03-13

    Shelf and coastal seas are regions of exceptionally high biological productivity, high rates of biogeochemical cycling and immense socio-economic importance. They are, however, poorly represented by the present generation of Earth system models, both in terms of resolution and process representation. Hence, these models cannot be used to elucidate the role of the coastal ocean in global biogeochemical cycles and the effects global change (both direct anthropogenic and climatic) are having on them. Here, we present a system for simulating all the coastal regions around the world (the Global Coastal Ocean Modelling System) in a systematic and practical fashion. It is based on automatically generating multiple nested model domains, using the Proudman Oceanographic Laboratory Coastal Ocean Modelling System coupled to the European Regional Seas Ecosystem Model. Preliminary results from the system are presented. These demonstrate the viability of the concept, and we discuss the prospects for using the system to explore key areas of global change in shelf seas, such as their role in the carbon cycle and climate change effects on fisheries.

  1. Global ocean circulation by altimetry

    NASA Technical Reports Server (NTRS)

    Wunsch, Carl; Haidvogel, D.

    1991-01-01

    The overall objectives of this project are to determine the general circulation of the oceans and many of its climate and biochemical consequences through the optimum use of altimetry data from TOPEX/POSEIDON and related missions. Emphasis is on the global-scale circulation, as opposed to the regional scale, but some more local studies will be carried out. Because of funding limitations, the primary initial focus will be on the time-dependent global-scale circulation rather than the mean; eventually, the mean circulation must be dealt with as well.

  2. A global distributed storage architecture

    NASA Technical Reports Server (NTRS)

    Lionikis, Nemo M.; Shields, Michael F.

    1996-01-01

    NSA architects and planners have come to realize that to gain the maximum benefit from, and keep pace with, emerging technologies, we must move to a radically different computing architecture. The compute complex of the future will be a distributed heterogeneous environment, where, to a much greater extent than today, network-based services are invoked to obtain resources. Among the rewards of implementing the services-based view are that it insulates the user from much of the complexity of our multi-platform, networked, computer and storage environment and hides its diverse underlying implementation details. In this paper, we will describe one of the fundamental services being built in our envisioned infrastructure; a global, distributed archive with near-real-time access characteristics. Our approach for adapting mass storage services to this infrastructure will become clear as the service is discussed.

  3. Enhanced deep ocean ventilation and oxygenation with global warming

    NASA Astrophysics Data System (ADS)

    Froelicher, T. L.; Jaccard, S.; Dunne, J. P.; Paynter, D.; Gruber, N.

    2014-12-01

    Twenty-first century coupled climate model simulations, observations from the recent past, and theoretical arguments suggest a consistent trend towards warmer ocean temperatures and fresher polar surface oceans in response to increased radiative forcing resulting in increased upper ocean stratification and reduced ventilation and oxygenation of the deep ocean. Paleo-proxy records of the warming at the end of the last ice age, however, suggests a different outcome, namely a better ventilated and oxygenated deep ocean with global warming. Here we use a four thousand year global warming simulation from a comprehensive Earth System Model (GFDL ESM2M) to show that this conundrum is a consequence of different rates of warming and that the deep ocean is actually better ventilated and oxygenated in a future warmer equilibrated climate consistent with paleo-proxy records. The enhanced deep ocean ventilation in the Southern Ocean occurs in spite of increased positive surface buoyancy fluxes and a constancy of the Southern Hemisphere westerly winds - circumstances that would otherwise be expected to lead to a reduction in deep ocean ventilation. This ventilation recovery occurs through a global scale interaction of the Atlantic Meridional Overturning Circulation undergoing a multi-centennial recovery after an initial century of transient decrease and transports salinity-rich waters inform the subtropical surface ocean to the Southern Ocean interior on multi-century timescales. The subsequent upwelling of salinity-rich waters in the Southern Ocean strips away the freshwater cap that maintains vertical stability and increases open ocean convection and the formation of Antarctic Bottom Waters. As a result, the global ocean oxygen content and the nutrient supply from the deep ocean to the surface are higher in a warmer ocean. The implications for past and future changes in ocean heat and carbon storage will be discussed.

  4. Ocean storage of nuclear wastes? Experiences from the Russian Arctic.

    PubMed

    Champ, M A; Gomez, L S; Makeyev, V M; Brooks, J M; Palmer, H D; Betz, F

    2001-01-01

    An international demonstration (RD&D) project for ocean storage of radioactive wastes should be proposed, to study the feasibility of the concept of ocean storage of nuclear waste. This international project should utilize the scientific, engineering and technical capabilities of selected universities, oceanographic institutions, NGOs and industries. This project would need to be an independent (non-governmental) study, utilizing the capabilities of selected universities, oceanographic institutions, environmental NGOs (Non-Governmental Organizations) and industries. Scientists and engineers first need to conduct an engineering, environmental, and economic feasibility study of the concept. The goal of the project would be to determine if ocean-based storage reduced the risks to the environment and public health to a greater degree than land-based storage. This would require comparing the risks and factors involved and making the data and information available to anyone, anywhere, anytime on the internet. The mere presence of an investigation of the ocean storage option could facilitate scientific and engineering competition between the two options, could subsequently reduce environmental and public risks and provide better protection and cost benefits in the system utilized. One of the primary concerns of the scientific community would be related to the sensitivity and precision of the monitoring of individaul containers on the ocean bottom. An advantage of the land-based option is that if there is a release, its presence could be detected at very low levels and be contained in the storage facility. On the ocean bottom, a release from a container might not be easily detected due to dispersion. Therefore the containment system would have to be a system within a system with monitoring between the two providing greater protection. Ocean storage may have greater technical and political hurdles than land-based options, but it may provide greater protection over time

  5. DOE Global Energy Storage Database

    DOE Data Explorer

    The DOE International Energy Storage Database has more than 400 documented energy storage projects from 34 countries around the world. The database provides free, up-to-date information on grid-connected energy storage projects and relevant state and federal policies. More than 50 energy storage technologies are represented worldwide, including multiple battery technologies, compressed air energy storage, flywheels, gravel energy storage, hydrogen energy storage, pumped hydroelectric, superconducting magnetic energy storage, and thermal energy storage. The policy section of the database shows 18 federal and state policies addressing grid-connected energy storage, from rules and regulations to tariffs and other financial incentives. It is funded through DOE’s Sandia National Laboratories, and has been operating since January 2012.

  6. Building a Global Ocean Science Education Network

    NASA Astrophysics Data System (ADS)

    Scowcroft, G. A.; Tuddenham, P. T.; Pizziconi, R.

    2016-02-01

    It is imperative for ocean science education to be closely linked to ocean science research. This is especially important for research that addresses global concerns that cross national boundaries, including climate related issues. The results of research on these critical topics must find its way to the public, educators, and students of all ages around the globe. To facilitate this, opportunities are needed for ocean scientists and educators to convene and identify priorities and strategies for ocean science education. On June 26 and 27, 2015 the first Global Ocean Science Education (GOSE) Workshop was convened in the United States at the University of Rhode Island Graduate School of Oceanography. The workshop, sponsored by the Consortium for Ocean Science Exploration and Engagement (COSEE) and the College of Exploration, had over 75 participants representing 15 nations. The workshop addressed critical global ocean science topics, current ocean science research and education priorities, advanced communication technologies, and leveraging international ocean research technologies. In addition, panels discussed elementary, secondary, undergraduate, graduate, and public education across the ocean basins with emphasis on opportunities for international collaboration. Special presentation topics included advancements in tropical cyclone forecasting, collaborations among Pacific Islands, ocean science for coastal resiliency, and trans-Atlantic collaboration. This presentation will focus on workshop outcomes as well as activities for growing a global ocean science education network. A summary of the workshop report will also be provided. The dates and location for the 2016 GOES Workshop will be announced. See http://www.coexploration.net/gose/index.html

  7. Decadal Changes in Global Ocean Chlorophyll

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Conkright, Margarita E.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    The global ocean chlorophyll archive produced by the Coastal Zone Color Scanner (CZCS) was revised using compatible algorithms with the Sea-viewing Wide Field-of-view Sensor (SeaWIFS), and both were blended with in situ data. This methodology permitted a quantitative comparison of decadal changes in global ocean chlorophyll from the CZCS (1979-1986) and SeaWiFS (Sep. 1997-Dec. 2000) records. Global seasonal means of ocean chlorophyll decreased over the two observational segments, by 8% in winter to 16% in autumn. Chlorophyll in the high latitudes was responsible for most of the decadal change. Conversely, chlorophyll concentrations in the low latitudes increased. The differences and similarities of the two data records provide evidence of how the Earth's climate may be changing and how ocean biota respond. Furthermore, the results have implications for the ocean carbon cycle.

  8. Global relationship between oceanic geoid and topography

    NASA Technical Reports Server (NTRS)

    Cazenave, A.; Dominh, K.; Allegre, C. J.; Marsh, J. G.

    1986-01-01

    The transfer function of geoid over topography as a function of wavelength is derived. The relationship between oceanic geoid and seafloor depth is analyzed. The correction of the geoid and topological data for thermal cooling of the oceanic lithosphere, sediment loading, and crustal thickening induced by volcanism under large ocean plateaus is discussed. The global residual depth and geoid anomalies are computed. The admittance and correlation between residual depth and geoid anomalies as a function of wavelength are examined.

  9. Ocean U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM)

    DTIC Science & Technology

    2008-10-01

    Ocean U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM) By Eric P. Chassignet1 and Harley E. Hurlburt2 1 COAPS ...UAcademia:U Florida State University/Center for Ocean-Atmospheric Prediction Studies ( COAPS ); University of Miami/Rosenstiel School of Marine and

  10. Global warming and changes in ocean circulation

    SciTech Connect

    Duffy, P.B.; Caldeira, K.C.

    1998-02-01

    This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.

  11. Multivariate Global Ocean Assimilation Studies

    DTIC Science & Technology

    2002-09-30

    representations of the four dimensional circulation of the ocean using data assimilation methods . We intend these representations to be applied in a variety of military, academic, as well as commercial applications.

  12. State of Climate 2011 - Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    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.; Yoder, J. A.

    2012-01-01

    Phytoplankton photosynthesis in the sun lit upper layer of the global ocean is the overwhelmingly dominant source of organic matter that fuels marine ecosystems. Phytoplankton contribute roughly half of the global (land and ocean) 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 ocean 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 climate-driven changes in the delivery of these resources to the euphotic zone

  13. Southern Ocean biological impacts on global ocean oxygen

    NASA Astrophysics Data System (ADS)

    Keller, David P.; Kriest, Iris; Koeve, Wolfgang; Oschlies, Andreas

    2016-06-01

    Southern Ocean (SO) physical and biological processes are known to have a large impact on global biogeochemistry. However, the role that SO biology plays in determining ocean oxygen concentrations is not completely understood. These dynamics are investigated here by shutting off SO biology in two marine biogeochemical models. The results suggest that SO biological processes reduce the ocean's oxygen content, mainly in the deep ocean, by 14 to 19%. However, since these processes also trap nutrients that would otherwise be transported northward to fuel productivity and subsequent organic matter export, consumption, and the accompanying oxygen consumption in midlatitude to low-latitude waters, SO biology helps to maintain higher oxygen concentrations in these subsurface waters. Thereby, SO biology can influence the size of the tropical oxygen minimum zones. As a result of ocean circulation the link between SO biological processes and remote oxygen changes operates on decadal to centennial time scales.

  14. Toward Submesocale Ocean Modelling and Observations for Global Ocean Forecast.

    NASA Astrophysics Data System (ADS)

    Drillet, Y.

    2014-12-01

    Mercator Ocean is the French oceanographic operational center involved in the development an operation of global high resolution ocean forecasting systems; it is part of the European Copernicus Marine service initiated during MyOcean project. Mercator Ocean currently delivers daily 1/12° global ocean forecast based on the NEMO model which allows for a good representation of mesoscale structures in main areas of the global ocean. Data assimilation of altimetry provides a precise initialization of the mesoscale structures while in situ observations, mainly based on the ARGO network, and satellite Sea Surface Temperature constrain water mass properties from the surface to intermediate depths. One of the main improvements scheduled in the coming years is the transitioning towards submesoscale permitting horizontal resolution (1/36°). On the basis of numerical simulations in selected areas and standard diagnostics developed to validate operational systems, we will discuss : i) The impact of the resolution increase at the basin scale. ii) Adequacy of numerical schemes, vertical resolution and physical parameterization. iii) Adequacy of currently implemented data assimilation procedures in particular with respect to new high resolution data set such as SWOT.

  15. Measuring Global Oceans and Terrestrial Freshwater From Space

    NASA Astrophysics Data System (ADS)

    Alsdorf, Doug; Fu, Lee-Lueng; Mognard, Nelly; Cazenave, Anny; Rodriguez, Ernesto; Chelton, Dudley; Lettenmaier, Dennis

    2007-06-01

    Radar altimetry has revolutionized oceanography by providing global measurements of ocean surface topography (OST [e.g., Fu and Cazenave, 2001]). Long-term measurements of large-scale circulation and heat storage of the global oceans have led to discoveries such as the effects of changes in ocean circulation on climate (e.g., El Niño and La Niña). A critical limitation, however, is the 200- to 300-kilometer spacings between satellite orbital tracks, which are unable to resolve the currents and oceanic mesoscale processes that contain 90% of the kinetic energy of the oceans. In contrast to ocean observations, surface freshwater measurements are limited mostly to in situ networks of gauges that record water surface elevations at fixed points along river channels. Globally, the spatial and temporal distribution of water stored on the land surface and moving through river channels is known only crudely. Furthermore, water movement in wetlands and across floodplains throughout the world is essentially unmeasured, significantly limiting our understanding of flood processes.

  16. Sustained growth of the Southern Ocean carbon storage in a warming climate

    NASA Astrophysics Data System (ADS)

    Ito, Takamitsu; Bracco, Annalisa; Deutsch, Curtis; Frenzel, Hartmut; Long, Matthew; Takano, Yohei

    2015-06-01

    We investigate the mechanisms controlling the evolution of Southern Ocean carbon storage under a future climate warming scenario. A subset of Coupled Model Intercomparison Project Phase 5 models predicts that the inventory of biologically sequestered carbon south of 40°S increases about 18-34 Pg C by 2100 relative to the preindustrial condition. Sensitivity experiments with an ocean circulation and biogeochemistry model illustrates the impacts of the wind and buoyancy forcings under a warming climate. Intensified and poleward shifted westerly wind strengthens the upper overturning circulation, not only leading to an increased uptake of anthropogenic CO2 but also releasing biologically regenerated carbon to the atmosphere. Freshening of Antarctic Surface Water causes a slowdown of the lower overturning circulation, leading to an increased Southern Ocean biological carbon storage. The rectified effect of these processes operating together is the sustained growth of the carbon storage in the Southern Ocean, even under the warming climate with a weaker global ocean carbon uptake.

  17. Improved Global Ocean Color Using Polymer Algorithm

    NASA Astrophysics Data System (ADS)

    Steinmetz, Francois; Ramon, Didier; Deschamps, ierre-Yves; Stum, Jacques

    2010-12-01

    A global ocean color product has been developed based on the use of the POLYMER algorithm to correct atmospheric scattering and sun glint and to process the data to a Level 2 ocean color product. Thanks to the use of this algorithm, the coverage and accuracy of the MERIS ocean color product have been significantly improved when compared to the standard product, therefore increasing its usefulness for global ocean monitor- ing applications like GLOBCOLOUR. We will present the latest developments of the algorithm, its first application to MODIS data and its validation against in-situ data from the MERMAID database. Examples will be shown of global NRT chlorophyll maps produced by CLS with POLYMER for operational applications like fishing or oil and gas industry, as well as its use by Scripps for a NASA study of the Beaufort and Chukchi seas.

  18. Carbon Storage in Biologic and Oceanic Reservoirs: Issues and Opportunities

    NASA Astrophysics Data System (ADS)

    Caldeira, K.

    2007-12-01

    Most discussion of carbon capture and storage have focused on geologic reservoirs because these are the reservoirs most likely to provide for long-term storage with a minimum of adverse environmental consequences. Nevertheless, there is interest in storage in other reservoirs such as the biosphere or the oceans. Storage in biological reservoirs such as forests or agricultural soils may in many cases be relatively inexpensive. Because this biological storage involves carbon dioxide removal from the atmosphere, it can potentially offset emissions from the transportation sector. Biological storage can be politically popular because it can be deployed with simple technologies, can be deployed in developing countries, and in many cases involves other environmental co-benefits. However, total capacity is limited. Furthermore, biological storage is temporary unless the store is actively maintained forever. Such temporary storage can be valuable, although it is clearly not as valuable as the quasi-permanent storage offered by good geologic storage reservoirs Ocean storage options fall into two main classes. The first involves conventional separation and compression of carbon dioxide from large point sources which would then be piped into the deep ocean and released either into the water or as a lake on the sea floor. In either case, the carbon dioxide would eventually interact with the atmosphere and contribute to ocean acidification. However, there is potential for the development of long-term engineered containment of carbon dioxide on or in the sea floor. The second main ocean storage option involves increasing ocean alkalinity, probably by dissolving carbonate minerals. This approach may offer safe, quasi- permanent, and cost-effective storage in settings where coastal carbon dioxide point sources are co-located with carbonate mineral deposits. Not every location or carbon dioxide source is suitable for geologic storage of carbon dioxide. At this early stage, it is

  19. Global Education for Ocean County College.

    ERIC Educational Resources Information Center

    Rykiel, Joan Devlin

    This paper presents a rationale for establishing a global education curriculum at Ocean County College (OCC) (New Jersey) and proposes a workable curriculum, along with suggestions for implementation. The author distinguishes between multicultural and global education--both curricula address issues of cultural diversity, human rights, and…

  20. Global Ocean Carbon and Biogeochemistry Coordination

    NASA Astrophysics Data System (ADS)

    Telszewski, Maciej; Tanhua, Toste; Palacz, Artur

    2016-04-01

    The complexity of the marine carbon cycle and its numerous connections to carbon's atmospheric and terrestrial pathways means that a wide range of approaches have to be used in order to establish it's qualitative and quantitative role in the global climate system. Ocean carbon and biogeochemistry research, observations, and modelling are conducted at national, regional, and global levels to quantify the global ocean uptake of atmospheric CO2 and to understand controls of this process, the variability of uptake and vulnerability of carbon fluxes into the ocean. These science activities require support by a sustained, international effort that provides a central communication forum and coordination services to facilitate the compatibility and comparability of results from individual efforts and development of the ocean carbon data products that can be integrated with the terrestrial, atmospheric and human dimensions components of the global carbon cycle. The International Ocean Carbon Coordination Project (IOCCP) was created in 2005 by the IOC of UNESCO and the Scientific Committee on Oceanic Research. IOCCP provides an international, program-independent forum for global coordination of ocean carbon and biogeochemistry observations and integration with global carbon cycle science programs. The IOCCP coordinates an ever-increasing set of observations-related activities in the following domains: underway observations of biogeochemical water properties, ocean interior observations, ship-based time-series observations, large-scale ocean acidification monitoring, inorganic nutrients observations, biogeochemical instruments and autonomous sensors and data and information creation. Our contribution is through the facilitation of the development of globally acceptable strategies, methodologies, practices and standards homogenizing efforts of the research community and scientific advisory groups as well as integrating the ocean biogeochemistry observations with the

  1. Requirements to Sustain Global Ocean Color Observations

    NASA Astrophysics Data System (ADS)

    Mengelt, C.; Yoder, J. A.; Antoine, D.; Del Castillo, C. E.; Evans, R. H.; Mobley, C.; Sarmiento, J. L.; Sathyendranath, S.; Schueler, C. F.; Siegel, D. A.; Wilson, C.

    2011-12-01

    Satellite measurements of ocean color provide a unique vantage point to measure global phytoplankton abundance and their contribution to the health of marine ecosystems, the global cycle of nutrients, oxygen, and carbon, and their response to long-term climate change. However, the United States is at risk of losing access to ocean color data because the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) has ceased operation, Moderate Resolution Imaging Spectroradiometer (MODIS) is aging and planned new satellite missions might not be able to acquire data at the accuracy levels required for climate research. Given the importance of maintaining the ocean color time-series, the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration, the National Science Foundation, and the Office of Naval Research requested the National Research Council (NRC) convene a committee of experts to review the minimum requirements to sustain global ocean color measurements for research and operational applications, and identify options to minimize the risk of a data gap. This poster summarizes the NRC report's findings. In particular, it reviews the minimum mission requirements to sustain at least the current capabilities for measuring ocean color at a global scale such as the need for post-launch vicarious calibration and monitoring of the sensor's stability. The poster will also summarize the report's recommendations regarding the options to improve the VIIRS/NPP mission. Moreover, it details how a data-centric planning effort could ensure that ocean color research can be advanced and maintained over the long term. The poster concludes that the ever broadening user community that depends on accurate and timely ocean color data highlights the urgency for fixing the VIIRS sensor and developing the next generation capability. In particular, NASA's climate continuity and decadal survey missions PACE/ACE, GEOCAPE and HyspIRI are required to advance ocean

  2. How Uncultivated Ocean Viruses Impact Global Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Sullivan, M. B.

    2016-12-01

    Ocean microbes drive local- and planetary-scale biogeochemical cycling, but do so under constraints imposed by viruses. Viruses can lyse microbes, which is thought to keep organic matter "small" and rapidly recycled (the `viral shunt'), but they can also metabolically reprogram their host cells by stealing "auxiliary metabolic genes" genes, or AMGs (e.g., photosynthesis genes for cyanobacterial viruses), from their hosts and using them to make more viruses during infection. Here I will present global-scale analyses that alter both of these paradigms. First, observations from viral metagenomic signatures suggest that viruses `sink' in the oceans, while network and modeling analyses revealed that a handful of viruses, rather than prokaryotes or eukaryotes, best predict carbon flux in the open oceans. These observations call into question the fundamental tenant of the viral shunt, and suggest that ocean viruses may aid sinking of carbon to the deep sea rather than constrain it to rapidly recycle in surface waters. Second, analyses from systematically collected and processed ocean viral metagenomic datasets (the Pacific Ocean Viromes and Global Ocean Viromes datasets) reveal that AMG-mediated viral metabolic reprogramming extends far beyond photosynthesis to also include nearly all of central carbon metabolism, as well as key genes in nitrogen and sulfur cycling. Together these findings suggest that viral roles in ocean biogeochemistry are extensive and provide a new baseline for future work designed to quantitatively evaluate the marine viral shunt.

  3. Ocean modeling in a global ocean observing system

    NASA Astrophysics Data System (ADS)

    Smith, Neville R.

    1993-08-01

    The oceanographic community is currently contemplating the design of a global ocean climate observing system to help monitor, describe, and understand the seasonal to decadal climate changes of the ocean and to provide the observations needed for climate prediction. This review attempts to define a role for modeling within that system, the central theme being that the observational and modeling elements must be developed in concert, with the presence of one enhancing the value of the other. Three distinct categories of model-to-data interface are identified. In the first class, models and data collection develop separately, being joined only by intermittent validation steps. In the second, and by far most important, class the model and data collection evolve together, either in a time-space data assimilation and prediction system, or through the application of inverse methods. In the final category, model information feeds back to the observing system design, and vice versa, and the model assimilation system provides quality control on the data. The key role of (atmospheric) models in the determination of surface fluxes to drive ocean models is discussed. A nontrivial role is proposed for ocean models whereby they provide additional, and largely independent, constraints on atmospheric forecast system estimates. The role of ocean models in the analysis of surface and upper ocean fields needs to be developed, particularly with respect to salinity and nonphysical fields. The use of models in rationalizing the choice of observation platforms is discussed, together with some of the difficulties in interpreting such studies. The state of tropical ocean prediction is reviewed with particular emphasis on systems that assimilate subsurface temperature data. A range of thermocline models are also reviewed with the emphasis on subduction and the problem of initializing and constraining models that resolve mesoscale eddies. Some of the issues involved in matching the models to

  4. Revaluating ocean warming impacts on global phytoplankton

    NASA Astrophysics Data System (ADS)

    Behrenfeld, Michael J.; O'Malley, Robert T.; Boss, Emmanuel S.; Westberry, Toby K.; Graff, Jason R.; Halsey, Kimberly H.; Milligan, Allen J.; Siegel, David A.; Brown, Matthew B.

    2016-03-01

    Global satellite observations document expansions of the low-chlorophyll central ocean gyres and an overall inverse relationship between anomalies in sea surface temperature and phytoplankton chlorophyll concentrations. These findings can provide an invaluable glimpse into potential future ocean changes, but only if the story they tell is accurately interpreted. Chlorophyll is not simply a measure of phytoplankton biomass, but also registers changes in intracellular pigmentation arising from light-driven (photoacclimation) and nutrient-driven physiological responses. Here, we show that the photoacclimation response is an important component of temporal chlorophyll variability across the global ocean. This attribution implies that contemporary relationships between chlorophyll changes and ocean warming are not indicative of proportional changes in productivity, as light-driven decreases in chlorophyll can be associated with constant or even increased photosynthesis. Extension of these results to future change, however, requires further evaluation of how the multifaceted stressors of a warmer, higher-CO2 world will impact plankton communities.

  5. Southern Ocean: Its involvement in global change

    SciTech Connect

    Gordon, A.L.

    1992-03-01

    Southern Ocean is the site of considerable water mass formation which cools and ventilates the modern world ocean. At the polar front zone, formation of cool, low salinity water sinks and spreads northward at intermediate depths limiting the downward penetration of the thermocline. Within the seasonal sea ice zone and along the margins of Antarctica, convection injects very cold oxygenated water into the deep and bottom ocean. These conditions developed as Antarctica shifted into its present configuration and grew a persistent glacial ice sheet, about 14 million years ago. The potential of the Southern Ocean to ventilate the deep and bottom ocean layers is related to occurrence of polynyas that form within the winter sea ice cover. Global climate changes would be expected to alter the polynya size and frequency. Under greenhouse-induced warming offshore polynyas may become less common as the static stability of the Southern Ocean mixed layer increases. This would diminish the Southern Ocean's cooling influence on the deep layers of the world ocean, resulting in a warmer deep ocean. The fate of coastal polynyas is less clear.

  6. Eddy Resolving Global Ocean Prediction including Tides

    DTIC Science & Technology

    2011-09-30

    for the global ocean. Isopycnal (density tracking) layers are best in the deep stratified ocean, pressure levels (nearly fixed depths) provide high...Adams, D. K., D. J. McGillicuddy Jr., L. Zamudio , A. M. Thurnherr, X. Liang, O. Rouxel, C. R. German, L. S. Mullineaux (2011), Surface-generated...Gaxiola-Castro, G., Zamudio , L., and Cervantes-Duarte, R. Net primary productivity, upwelling and coastal currents in the Gulf of Ulloa, Baja

  7. Including eddies in global ocean models

    NASA Astrophysics Data System (ADS)

    Semtner, Albert J.; Chervin, Robert M.

    The ocean is a turbulent fluid that is driven by winds and by surface exchanges of heat and moisture. It is as important as the atmosphere in governing climate through heat distribution, but so little is known about the ocean that it remains a “final frontier” on the face of the Earth. Many ocean currents are truly global in extent, such as the Antarctic Circumpolar Current and the “conveyor belt” that connects the North Atlantic and North Pacific oceans by flows around the southern tips of Africa and South America. It has long been a dream of some oceanographers to supplement the very limited observational knowledge by reconstructing the currents of the world ocean from the first principles of physics on a computer. However, until very recently, the prospect of doing this was thwarted by the fact that fluctuating currents known as “mesoscale eddies” could not be explicitly included in the calculation.

  8. Ocean plankton. Structure and function of the global ocean microbiome.

    PubMed

    Sunagawa, Shinichi; Coelho, Luis Pedro; Chaffron, Samuel; Kultima, Jens Roat; Labadie, Karine; Salazar, Guillem; Djahanschiri, Bardya; Zeller, Georg; Mende, Daniel R; Alberti, Adriana; Cornejo-Castillo, Francisco M; Costea, Paul I; Cruaud, Corinne; d'Ovidio, Francesco; Engelen, Stefan; Ferrera, Isabel; Gasol, Josep M; Guidi, Lionel; Hildebrand, Falk; Kokoszka, Florian; Lepoivre, Cyrille; Lima-Mendez, Gipsi; Poulain, Julie; Poulos, Bonnie T; Royo-Llonch, Marta; Sarmento, Hugo; Vieira-Silva, Sara; Dimier, Céline; Picheral, Marc; Searson, Sarah; Kandels-Lewis, Stefanie; Bowler, Chris; de Vargas, Colomban; Gorsky, Gabriel; Grimsley, Nigel; Hingamp, Pascal; Iudicone, Daniele; Jaillon, Olivier; Not, Fabrice; Ogata, Hiroyuki; Pesant, Stephane; Speich, Sabrina; Stemmann, Lars; Sullivan, Matthew B; Weissenbach, Jean; Wincker, Patrick; Karsenti, Eric; Raes, Jeroen; Acinas, Silvia G; Bork, Peer

    2015-05-22

    Microbes are dominant drivers of biogeochemical processes, yet drawing a global picture of functional diversity, microbial community structure, and their ecological determinants remains a grand challenge. We analyzed 7.2 terabases of metagenomic data from 243 Tara Oceans samples from 68 locations in epipelagic and mesopelagic waters across the globe to generate an ocean microbial reference gene catalog with >40 million nonredundant, mostly novel sequences from viruses, prokaryotes, and picoeukaryotes. Using 139 prokaryote-enriched samples, containing >35,000 species, we show vertical stratification with epipelagic community composition mostly driven by temperature rather than other environmental factors or geography. We identify ocean microbial core functionality and reveal that >73% of its abundance is shared with the human gut microbiome despite the physicochemical differences between these two ecosystems.

  9. Map of moisture over global oceans

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This map shows the presence of water vapor over global oceans. The imagery was produced by combining Special Sensor Microwave Imager measurements and computer models. This data will help scientists better understand how weather systems move water vapor from the tropics toward the poles producing precipitation.

  10. Global oceanic production of nitrous oxide

    PubMed Central

    Freing, Alina; Wallace, Douglas W. R.; Bange, Hermann W.

    2012-01-01

    We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N2O) to estimate the concentration of biologically produced N2O and N2O production rates in the ocean on a global scale. Our approach to estimate the N2O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N2O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N2O are not taken into account in our study. The largest amount of subsurface N2O is produced in the upper 500 m of the water column. The estimated global annual subsurface N2O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr−1. This is in agreement with estimates of the global N2O emissions to the atmosphere and indicates that a N2O source in the mixed layer is unlikely. The potential future development of the oceanic N2O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed. PMID:22451110

  11. Global oceanic production of nitrous oxide.

    PubMed

    Freing, Alina; Wallace, Douglas W R; Bange, Hermann W

    2012-05-05

    We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N(2)O) to estimate the concentration of biologically produced N(2)O and N(2)O production rates in the ocean on a global scale. Our approach to estimate the N(2)O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N(2)O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N(2)O are not taken into account in our study. The largest amount of subsurface N(2)O is produced in the upper 500 m of the water column. The estimated global annual subsurface N(2)O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr(-1). This is in agreement with estimates of the global N(2)O emissions to the atmosphere and indicates that a N(2)O source in the mixed layer is unlikely. The potential future development of the oceanic N(2)O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed.

  12. Achieving Global Ocean Color Climate Data Records

    NASA Technical Reports Server (NTRS)

    Franz, Bryan

    2010-01-01

    Ocean color, or the spectral distribution of visible light upwelling from beneath the ocean surface, carries information on the composition and concentration of biological constituents within the water column. The CZCS mission in 1978 demonstrated that quantitative ocean color measurements could be. made from spaceborne sensors, given sufficient corrections for atmospheric effects and a rigorous calibration and validation program. The launch of SeaWiFS in 1997 represents the beginning of NASA's ongoing efforts to develop a continuous ocean color data record with sufficient coverage and fidelity for global change research. Achievements in establishing and maintaining the consistency of the time-series through multiple missions and varying instrument designs will be highlighted in this talk, including measurements from NASA'S MODIS instruments currently flying on the Terra and Aqua platforms, as well as the MERIS sensor flown by ESA and the OCM-2 sensor recently launched by ISRO.

  13. The Global Ocean Observing System: One perspective

    NASA Technical Reports Server (NTRS)

    Wilson, J. Ron

    1992-01-01

    This document presents a possible organization for a Global Ocean Observing System (GOOS) within the Intergovernmental Oceanographic Commission and the joint ocean programs with the World Meteorological Organization. The document and the organization presented here is not intended to be definitive, complete or the best possible organization for such an observation program. It is presented at this time to demonstrate three points. The first point to be made is that an international program office for GOOS along the lines of the WOCE and TOGA IPOs is essential. The second point is that national programs will have to continue to collect data at the scale of WOCE plus TOGA and more. The third point is that there are many existing groups and committees within the IOC and joint IOC/WMO ocean programs that can contribute essential experience to and form part of the basis of a Global Ocean Observing System. It is particularly important to learn from what has worked and what has not worked in the past if a successful ocean observing system is to result.

  14. Characterizing global infrasonic ocean ambient noise

    NASA Astrophysics Data System (ADS)

    Le Pichon, Alexis; Stutzman, Eleonore; Arduin, Fabrice; Sylvain, Leon

    2017-04-01

    The ability of the International Monitoring System (IMS) global infrasound network to detect atmospheric explosions and events of interest strongly depends on station specific ambient noise which includes both incoherent wind noise and real coherent infrasonic waves. To characterize the coherent ambient noise, a broadband array processing was performed on 10 years of continuous recordings at IMS stations. Multi-year comparisons between the observed and modeled directional microbarom amplitude variations at several IMS stations using two-dimensional wave energy spectrum ocean wave products are performed to build of a reference database of infrasound oceanic sources. Microseisms are attributed the same source processes as microbaroms, involving the interaction of standing ocean waves. To further evaluate oceanic wave action models, the infrasound analysis will be supplemented with several other approaches including microseisms collected at seismic instrumentation (single stations and arrays). The expected benefits of such studies concern the use of multi-year complementary data to finely characterize coupling mechanisms at the ocean-atmosphere interface. In return, a better knowledge of the source of the ambient ocean noise opens new perspectives by providing additional integrated constraints on the dynamics of the middle atmosphere and its disturbances where data coverage is sparse.

  15. III: OCEAN CIRCULATION: Global Ocean Data Assimilation and Geoid Measurements

    NASA Astrophysics Data System (ADS)

    Wunsch, C.; Stammer, D.

    2003-07-01

    Parts of geodesy and physical oceanography are about to mature into a single modeling problem involving the simultaneous estimation of the marine geoid and the general circulation. Both fields will benefit. To this end, we present an ocean state estimation (data assimilation) framework which is designed to obtain a dynamically consistent picture of the changing ocean circulation by combining global ocean data sets of arbitrary type with a general circulation model (GCM). The impact of geoid measurements on such estimates of the ocean circulation are numerous. For the mean circulation, a precise geoid describes the reference frame for dynamical signals in altimetric sea surface height observations. For the time-varying ocean signal, changing geoid information might be a valuable new information about correcting the changing flow field on time scales from a few month to a year, but the quantitative utility of such information has not yet been demonstrated. For a consistent estimate, some knowledge of the prior error covariances of all data fields is required. The final result must be consistent with prior error estimates for the data. State estimation is thus one of the few quantitative consistency checks for new geoid measurements anticipated from forthcoming space missions. Practical quantitative methods will yield a best possible estimate of the dynamical sea surface which, when combined with satellite altimetric surfaces, will produce a best-estimate marine geoid. The anticipated accuracy and precision of such estimates raises some novel modeling error issues which have not conventionally been of concern (the Boussinesq approximation, self-attraction and loading). Model skill at very high frequencies is a major concern because of the need to de-alias the data obtained by the inevitable oceanic temporal undersampling dictated by realistic satellite orbit configurations.

  16. Recent Trends in Global Ocean Chlorophyll

    NASA Technical Reports Server (NTRS)

    Gregg, Watson; Casey, Nancy

    2004-01-01

    Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 5% since 1998. The North Pacific ocean basin has increased nearly 19%. To understand the causes of these trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The mode1 utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. Ths enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll.

  17. Recent Trends in Global Ocean Chlorophyll

    NASA Technical Reports Server (NTRS)

    Gregg, Watson; Casey, Nancy

    2004-01-01

    Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 5% since 1998. The North Pacific ocean basin has increased nearly 19%. To understand the causes of these trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The mode1 utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. Ths enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll.

  18. Robust warming of the global upper ocean.

    PubMed

    Lyman, John M; Good, Simon A; Gouretski, Viktor V; Ishii, Masayoshi; Johnson, Gregory C; Palmer, Matthew D; Smith, Doug M; Willis, Josh K

    2010-05-20

    A large ( approximately 10(23) J) multi-decadal globally averaged warming signal in the upper 300 m of the world's oceans was reported roughly a decade ago and is attributed to warming associated with anthropogenic greenhouse gases. The majority of the Earth's total energy uptake during recent decades has occurred in the upper ocean, but the underlying uncertainties in ocean warming are unclear, limiting our ability to assess closure of sea-level budgets, the global radiation imbalance and climate models. For example, several teams have recently produced different multi-year estimates of the annually averaged global integral of upper-ocean heat content anomalies (hereafter OHCA curves) or, equivalently, the thermosteric sea-level rise. Patterns of interannual variability, in particular, differ among methods. Here we examine several sources of uncertainty that contribute to differences among OHCA curves from 1993 to 2008, focusing on the difficulties of correcting biases in expendable bathythermograph (XBT) data. XBT data constitute the majority of the in situ measurements of upper-ocean heat content from 1967 to 2002, and we find that the uncertainty due to choice of XBT bias correction dominates among-method variability in OHCA curves during our 1993-2008 study period. Accounting for multiple sources of uncertainty, a composite of several OHCA curves using different XBT bias corrections still yields a statistically significant linear warming trend for 1993-2008 of 0.64 W m(-2) (calculated for the Earth's entire surface area), with a 90-per-cent confidence interval of 0.53-0.75 W m(-2).

  19. Ensemble-based global ocean data assimilation

    NASA Astrophysics Data System (ADS)

    Nadiga, Balasubramanya T.; Casper, W. Riley; Jones, Philip W.

    2013-12-01

    We present results of experiments performing global, ensemble-based, ocean-only data assimilation and assess the utility of such data assimilation in improving model predictions. The POP (Parallel Ocean Program) Ocean General Circulation Model (OGCM) is forced by interannually varying atmospheric fields of version 2 of the Coordinated Ocean Reference Experiment (CORE) data set, and temperature and salinity observations from the World Ocean Database 2009 (WOD09) are assimilated. The assimilation experiments are conducted over a period of about two years starting January 1, 1990 using the framework of the Data Assimilation Research Testbed (DART). We find that an inflation scheme that blends the ensemble-based sample error covariance with a static estimate of ensemble spread is necessary for the assimilations to be effective in the ocean model. We call this Climatology-based Spread Inflation or CSI for short. The effectiveness of the proposed inflation scheme is investigated in a low-order model; a series of experiments in this context demonstrates its effectiveness. Using a number of diagnostics, we show that the resulting assimilated state of ocean circulation is more realistic: In particular, the sea surface temperature (SST) shows reduced errors with respect to an unassimilated SST data set, and the subsurface temperature shows reduced errors with respect to observations. Finally, towards assessing the utility of assimilations for predictions, we show that the use of an assimilated state as initial condition leads to improved hindcast skill over a significant period of time; that is when the OGCM is initialized with an assimilated state and run forward, it is better able to predict unassimilated observations of the WOD09 than a control non-assimilating run (≈ 20% reduction in error) over a period of about three months. The loss of skill beyond this period is conjectured to be due, in part, to model error and prevents an improvement in the representation of

  20. Global oceanic emissions of nitrous oxide

    SciTech Connect

    Nevison, C.D.; Erickson, D.J.; Weiss, R.F.

    1995-08-15

    The global N{sub 2}O flux from the ocean to the atmosphere is calculated based on more than 60,000 expedition measurements of the N{sub 2}O anomaly in surface water. The expedition data are coupled to daily air-sea gas transfer coefficients modeled at 2.8{degrees} x 2.8{degrees} resolution to estimate a global ocean source of about 4 (1.2-6.8) Tg N yr{sup {minus}1}. The strongest source is predicted from the 40-60{degrees}S latitude band. Strong emissions also are predicted from the northern Pacific Ocean, the equatorial upwelling zone, and coastal upwelling zones occurring predominantly in the tropical northern hemisphere. High apparent oxygen utilization (AOU) at 100 m below the mixed layer is found to be correlated positively both to N{sub 2}O production at depth and to the surface N{sub 2}O anomaly. On the basis of these correlations, the expedition data are partitioned into two subsets associated with high and low AOU at depth. The zonally averaged monthly means in each subset are extrapolated to produce two latitude-by-month matrices in which monthly surface N{sub 2}O is expressed as the deviation from the annual mean. Both matrices contain large uncertainties. The low-AOU matrix, which mainly includes surface N{sub 2}O data from the North Atlantic and the subtropical gyres, suggests many regions with positive summer deviations and negative winter deviations, consistent with a seasonal cycle predominantly driven by seasonal heating and cooling of the surface ocean. The high-AOU subset, which includes the regions most important to the global N{sub 2}O ocean source, suggests some regions with positive winter deviations and negative summer deviations, consistent with a seasonal cycle predominantly driven by wintertime mixing of surface water with N{sub 2}O-rich deep water. Coupled seasonal changes in gas transfer coefficients and surface N{sub 2}O in these important source regions could strongly influence the global ocean source. 36 refs., 12 figs., 3 tabs.

  1. Biogeography of the Global Ocean's Mesopelagic Zone.

    PubMed

    Proud, Roland; Cox, Martin J; Brierley, Andrew S

    2017-01-09

    The global ocean's near surface can be partitioned into distinct provinces on the basis of regional primary productivity and oceanography [1]. This ecological geography provides a valuable framework for understanding spatial variability in ecosystem function but has relevance only partway into the epipelagic zone (the top 200 m). The mesopelagic (200-1,000 m) makes up approximately 20% of the global ocean volume, plays important roles in biogeochemical cycling [2], and holds potentially huge fish resources [3-5]. It is, however, hidden from satellite observation, and a lack of globally consistent data has prevented development of a global-scale understanding. Acoustic deep scattering layers (DSLs) are prominent features of the mesopelagic. These vertically narrow (tens to hundreds of m) but horizontally extensive (continuous for tens to thousands of km) layers comprise fish and zooplankton and are readily detectable using echosounders. We have compiled a database of DSL characteristics globally. We show that DSL depth and acoustic backscattering intensity (a measure of biomass) can be modeled accurately using just surface primary productivity, temperature, and wind stress. Spatial variability in these environmental factors leads to a natural partition of the mesopelagic into ten distinct classes. These classes demark a more complex biogeography than the latitudinally banded schemes proposed before [6, 7]. Knowledge of how environmental factors influence the mesopelagic enables future change to be explored: we predict that by 2100 there will be widespread homogenization of mesopelagic communities and that mesopelagic biomass could increase by approximately 17%. The biomass increase requires increased trophic efficiency, which could arise because of ocean warming and DSL shallowing.

  2. Accelerated Prediction of the Polar Ice and Global Ocean (APPIGO)

    DTIC Science & Technology

    2013-09-30

    SEP 2013 2. REPORT TYPE 3. DATES COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Accelerated Prediction of the Polar Ice and Global...the Polar Ice and Global Ocean (APPIGO) Eric P. Chassignet Center for Ocean-Atmospheric Prediction Studies Florida State University phone: (850...architectures. These codes form the ocean and sea ice components of the Navy’s Arctic Cap Nowcast/Forecast System (ACNFS) and the Navy Global Ocean

  3. SubArctic Oceans and Global Climate

    NASA Astrophysics Data System (ADS)

    Rhines, P. B.

    2004-12-01

    The passages connecting the Arctic Ocean with the Atlantic and Pacific, and their `mediterranean' basins, are focal points for the global meridional overturning circulation, and all of the climate impacts which this implies. It is also a difficult region to model accurately: the sensitivity of climate models to subpolar ocean dynamics is well-known. In this talk we stress the need to instrument and analyze the subpolar oceans, and some examples of sustained observations developing there. Results from satellite altimetry, recent Seaglider deployments from Greenland, and mooring arrays will be described. In particular we show the first Seaglider sections of hydrography and bio-optical profiles of the Labrador Sea (one of the first extended deployments of this autonomous undersea vehicle); we discuss the decline during the 1990s of the subpolar gyre circulation of the Atlantic from its great strength during the positive NAO period of the early 1990s, and its relevance to the salinity decline observed over a much longer period; we review observations of the flows at the Iceland-Scotland Ridge and Davis Strait, argued in terms of volume transport plots on the potential temperature/salinity plane; we display maps of the `convection resistance' (related to dynamic height) and its sensitivity to surface low-salinity water masses and their partition between shallow continental shelves and deep ocean. This is a particularly exciting time for climate studies, with fundamental properties of the atmosphere-ocean circulation under debate, even before one considers natural and human-induced variability. Is the four-decade long decline in subArctic salinity the result of increased hydrologic cycle, increased or altered Arctic outflow to the Atlantic, or slowing of the subpolar circulation? Is the basic intensity of the MOC more dependent on high-latitude buoyancy forcing, or wind- or tide-driven mixing in the upwelling branch, or possibly wind-stress at high latitude? Is the

  4. Adaptive wavelet simulation of global ocean dynamics

    NASA Astrophysics Data System (ADS)

    Kevlahan, N. K.-R.; Dubos, T.; Aechtner, M.

    2015-07-01

    In order to easily enforce solid-wall boundary conditions in the presence of complex coastlines, we propose a new mass and energy conserving Brinkman penalization for the rotating shallow water equations. This penalization does not lead to higher wave speeds in the solid region. The error estimates for the penalization are derived analytically and verified numerically for linearized one dimensional equations. The penalization is implemented in a conservative dynamically adaptive wavelet method for the rotating shallow water equations on the sphere with bathymetry and coastline data from NOAA's ETOPO1 database. This code could form the dynamical core for a future global ocean model. The potential of the dynamically adaptive ocean model is illustrated by using it to simulate the 2004 Indonesian tsunami and wind-driven gyres.

  5. Is low frequency ocean sound increasing globally?

    PubMed

    Miksis-Olds, Jennifer L; Nichols, Stephen M

    2016-01-01

    Low frequency sound has increased in the Northeast Pacific Ocean over the past 60 yr [Ross (1993) Acoust. Bull. 18, 5-8; (2005) IEEE J. Ocean. Eng. 30, 257-261; Andrew, Howe, Mercer, and Dzieciuch (2002) J. Acoust. Soc. Am. 129, 642-651; McDonald, Hildebrand, and Wiggins (2006) J. Acoust. Soc. Am. 120, 711-717; Chapman and Price (2011) J. Acoust. Soc. Am. 129, EL161-EL165] and in the Indian Ocean over the past decade, [Miksis-Olds, Bradley, and Niu (2013) J. Acoust. Soc. Am. 134, 3464-3475]. More recently, Andrew, Howe, and Mercer's [(2011) J. Acoust. Soc. Am. 129, 642-651] observations in the Northeast Pacific show a level or slightly decreasing trend in low frequency noise. It remains unclear what the low frequency trends are in other regions of the world. In this work, data from the Comprehensive Nuclear-Test Ban Treaty Organization International Monitoring System was used to examine the rate and magnitude of change in low frequency sound (5-115 Hz) over the past decade in the South Atlantic and Equatorial Pacific Oceans. The dominant source observed in the South Atlantic was seismic air gun signals, while shipping and biologic sources contributed more to the acoustic environment at the Equatorial Pacific location. Sound levels over the past 5-6 yr in the Equatorial Pacific have decreased. Decreases were also observed in the ambient sound floor in the South Atlantic Ocean. Based on these observations, it does not appear that low frequency sound levels are increasing globally.

  6. Coccolithophorid blooms in the global ocean

    NASA Technical Reports Server (NTRS)

    Brown, Christopher W.; Yoder, James A.

    1994-01-01

    The global distribution pattern of coccolithophrid blooms was mapped in order to ascertain the prevalence of these blooms in the world's oceans and to estimate their worldwide production of CaCO3 and dimethyl sulfide (DMS). Mapping was accomplished by classifying pixels of 5-day global composites of coastal zone color scanner imagery into bloom and nonbloom classes using a supervised, multispectral classification scheme. Surface waters with the spectral signature of coccolithophorid blooms annually covered an average of 1.4 x 10(exp 6) sq km in the world oceans from 1979 to 1985, with the subpolar latitudes accounting for 71% of this surface area. Classified blooms were most extensive in the Subartic North Atlantic. Large expanses of the bloom signal were also detected in the North Pacific, on the Argentine shelf and slope, and in numerous lower latitude marginal seas and shelf regions. The greatest spatial extent of classified blooms in subpolar oceanic regions occurred in the months from summer to early autumn, while those in lower latitude marginal seas occurred in midwinter to early spring. Though the classification scheme was effcient in separating bloom and nonbloom classes during test simulations, and biogeographical literature generally confirms the resulting distribution pattern of blooms in the subpolar regions, the cause of the bloom signal is equivocal in some geographic areas, particularly on shelf regions at lower latitudes. Standing stock estimates suggest that the presumed Emiliania huxleyi blooms act as a significant source of calcite carbon and DMS sulfur on a regional scale. On a global scale, however, the satellite-detected coccolithophorid blooms are estimated to play only a minor role in the annual production of these two compounds and their flux from the surface mixed layer.

  7. Global Warming 'Pause' - Oceans Reshuffle Heat

    NASA Astrophysics Data System (ADS)

    Nieves, V.; Willis, J. K.; Patzert, W. C.

    2015-12-01

    Despite the fact that greenhouse gases are still increasing and all other indicators show warming-related change (+0.0064 °C/year since 1880 or +0.0077 °C/year during 1993-2002), surface temperatures stopped climbing steadily during the past decade at a rate of +0.0010 °C/year from 2003 to 2012. We show that in recent years, the heat was being trapped in the subsurface waters of the western Pacific and eastern Indian oceans between 100 and 300 m. The movement of warm Pacific water below the surface, also related to the Pacific Decadal Oscillation climatic pattern, temporarily affected surface temperatures and accounted for the global cooling trend in surface temperature. With the Pacific Decadal Oscillation possibly changing to a warm phase, it is likely that the oceans will drive a major surge in global surface warming sometime in the next decade or two. Reference: Nieves, V., Willis, J. K., and Patzert, W. C. (2015). Recent hiatus caused by decadal shift in Indo-Pacific heating. Science, aaa4521.

  8. The post-2002 global surface warming slowdown caused by the subtropical Southern Ocean heating acceleration

    NASA Astrophysics Data System (ADS)

    Oka, A.; Watanabe, M.

    2017-04-01

    The warming rate of global mean surface temperature slowed down during 1998-2012. Previous studies pointed out role of increasing ocean heat uptake during this global warming slowdown, but its mechanism remains under discussion. Our numerical simulations, in which wind stress anomaly in the equatorial Pacific is imposed from reanalysis data, suggest that subsurface warming in the equatorial Pacific took place during initial phase of the global warming slowdown (1998-2002), as previously reported. It is newly clarified that the Ekman transport from tropics to subtropics is enhanced during the later phase of the slowdown (after 2002) and enhanced subtropical Ekman downwelling causes accelerated heat storage below depth of 700 m in the subtropical Southern Ocean, leading to the post-2002 global warming slowdown. Observational data of ocean temperature also support this scenario. This study provides clear evidence that deeper parts of the Southern Ocean play a critical role in the post-2002 warming slowdown.

  9. Modeling Coccolithophores in the Global Oceans

    NASA Astrophysics Data System (ADS)

    Gregg, W.

    2006-12-01

    Coccolithophores are important ecological and geochemical components of the global oceans. A global three- dimensional model was used to simulate their distributions in a multi-phytoplankton context. The realism of the simulation was supported by comparisons of model surface nutrients and total chlorophyll with in situ and satellite observations. Nitrate, silica, and dissolved iron surface distributions were positively correlated with in situ data across major oceanographic basins. Global annual departures were +18.9% for nitrate (model high), +5.4% for silica, and +45.0% for iron. Total surface chlorophyll was also positively correlated with satellite and in situ data sets across major basins. Global annual departures were -8.0% with SeaWiFS (model low), +1.1% with Aqua, and -17.1% with in situ data. Global annual primary production estimates were within 1% and 9% of estimates derived from SeaWiFS and Aqua, respectively, using a common primary production algorithm. Coccolithophore annual mean relative abundances were 2.6% lower than observations, but were positively correlated across basins. Two of the other three phytoplankton groups, diatoms and cyanobacteria, were also positively correlated with observations. Distributions of coccolithophores were dependent upon interactions and competition with the other phytoplankton groups. In this model coccolithophores had a competitive advantage over diatoms and chlorophytes by virtue of a greater ability to utilize nutrients and light at low values. However, their higher sinking rates placed them at a disadvantage when nutrients and light were plentiful. In very low nutrient conditions, such as the mid-ocean gyres, coccolithophores were unable to compete with the efficient nutrient utilization capability and low sinking rate of cyanobacteria. Comparisons of simulated coccolithophore distributions with satellite-derived estimates of calcite concentration and coccolithophore blooms showed some agreement, but also areas of

  10. Modeling coccolithophores in the global oceans

    NASA Astrophysics Data System (ADS)

    Gregg, Watson W.; Casey, Nancy W.

    2007-03-01

    Coccolithophores are important ecological and geochemical components of the global oceans. A global three-dimensional model was used to simulate their distributions in a multi-phytoplankton context. The realism of the simulation was supported by comparisons of model surface nutrients and total chlorophyll with in situ and satellite observations. Nitrate, silica, and dissolved iron surface distributions were positively correlated with in situ data across major oceanographic basins. Global annual departures were +18.9% for nitrate (model high), +5.4% for silica, and +45.0% for iron. Total surface chlorophyll was also positively correlated with satellite and in situ data sets across major basins. Global annual departures were -8.0% with Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (model low), +1.1% with Aqua, and -17.1% with in situ data. Global annual primary production estimates were within 1% and 9% of estimates derived from SeaWiFS and Aqua, respectively, using a common primary production algorithm. Coccolithophore annual mean relative abundances were 2.6% lower than observations, but were positively correlated across basins. Two of the other three phytoplankton groups, diatoms and cyanobacteria, were also positively correlated with observations. Distributions of coccolithophores were dependent upon interactions and competition with the other phytoplankton groups. In this model, coccolithophores had a competitive advantage over diatoms and chlorophytes by virtue of a greater ability to utilize nutrients and light at low values. However, their higher sinking rates placed them at a disadvantage when nutrients and light were plentiful. In very low nutrient conditions, such as the mid-ocean gyres, coccolithophores were unable to compete with the efficient nutrient utilization capability and low sinking rate of cyanobacteria. Comparisons of simulated coccolithophore distributions with satellite-derived estimates of calcite concentration and coccolithophore blooms

  11. Pliocene oceanic seaways and global climate.

    PubMed

    Karas, Cyrus; Nürnberg, Dirk; Bahr, André; Groeneveld, Jeroen; Herrle, Jens O; Tiedemann, Ralf; deMenocal, Peter B

    2017-01-05

    Tectonically induced changes in oceanic seaways had profound effects on global and regional climate 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. Model 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 climate 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 model simulations of the impacts of Central American Seaway closure a strengthened AMOC with a global climate 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.

  12. Pliocene oceanic seaways and global climate

    PubMed Central

    Karas, Cyrus; Nürnberg, Dirk; Bahr, André; Groeneveld, Jeroen; Herrle, Jens O.; Tiedemann, Ralf; deMenocal, Peter B.

    2017-01-01

    Tectonically induced changes in oceanic seaways had profound effects on global and regional climate 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. Model 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 climate 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, δ18O) in combination with a recently published benthic stable carbon isotope (δ13C) 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 model simulations of the impacts of Central American Seaway closure a strengthened AMOC with a global climate 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. PMID:28054561

  13. Pliocene oceanic seaways and global climate

    NASA Astrophysics Data System (ADS)

    Karas, Cyrus; Nürnberg, Dirk; Bahr, André; Groeneveld, Jeroen; Herrle, Jens O.; Tiedemann, Ralf; Demenocal, Peter B.

    2017-01-01

    Tectonically induced changes in oceanic seaways had profound effects on global and regional climate 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. Model 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 climate 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, δ18O) in combination with a recently published benthic stable carbon isotope (δ13C) 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 model simulations of the impacts of Central American Seaway closure a strengthened AMOC with a global climate 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.

  14. Global Characterization of the Ocean Ridge System

    NASA Astrophysics Data System (ADS)

    Gale, A.; Langmuir, C. H.; Dalton, C. A.

    2010-12-01

    The mid-ocean ridge system is a window into the upper mantle, producing over 80% of Earth’s volcanism. Fundamental, first-order questions remain debated and require a reliable global perspective. Such questions include the relative roles of mantle temperature, mantle heterogeneity and spreading rate on mid-ocean ridge basalt (MORB) compositions, and the importance of spreading rate to melting and fractionation processes. To address these issues and provide a common reference for geochemists and geophysicists, we have assembled a comprehensive petrological presentation of global MORB. The data are compiled from PetDB as well as unpublished data. Transforming the raw data into a useful catalog poses several challenges. First, to link each sample with a particular ridge segment requires defining the individual segments of the ridge system. Using the highest resolution bathymetry available, we identified 771 global ridge segments with a total length of 60,864km. For each segment we also generated a digital along-strike depth profile, enabling precise characterization of both mean depth and depth range. Second, as noted in earlier work, different laboratories calibrate their analyses to different standards, which can lead to significant, systematic offsets among analyses. It is therefore important to apply correction factors to the data to make them consistent with one another. Erroneous data and mislocated samples were identified and either eliminated or manually corrected, leading to a total dataset of 11,366 glass and 874 whole-rock analyses that have had interlab correction values carefully applied. These results show that the mean depth of the global ridge system is 2981m, calculated by averaging the segment mean depths, weighted by segment length. Of the 771 ridge segments, 476 have at least one basalt sample within 10km of the ridge axis but only 181 segments have samples from three or more unique locations. Using these data, a far more reliable composition can

  15. Global Ocean on Enceladus Artist Rendering

    NASA Image and Video Library

    2015-09-15

    This illustration is a speculative representation of the interior of Saturn's moon Enceladus with a global liquid water ocean between its rocky core and icy crust. The thickness of layers shown here is not to scale. Scientists on NASA's Cassini mission determined that the slight wobble of Enceladus as it orbits Saturn is much too large for the moon to be frozen from surface to core. The wobble, technically referred to as a libration, reveals that the crust of Enceladus is disconnected from its rocky interior. This graphic is an update to PIA19058, which showed only a regional sea beneath the south polar region of Enceladus. Enceladus is 313 miles (504 kilometers) across. http://photojournal.jpl.nasa.gov/catalog/PIA19656

  16. Picophytoplankton biomass distribution in the global ocean

    NASA Astrophysics Data System (ADS)

    Buitenhuis, E. T.; Li, W. K. W.; Vaulot, D.; Lomas, M. W.; Landry, M. R.; Partensky, F.; Karl, D. M.; Ulloa, O.; Campbell, L.; Jacquet, S.; Lantoine, F.; Chavez, F.; Macias, D.; Gosselin, M.; McManus, G. B.

    2012-08-01

    The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1° spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins, and at least some data in all other basins. The average picophytoplankton biomass is 12 ± 22 μg C l-1 or 1.9 g C m-2. We estimate a total global picophytoplankton biomass of 0.53-1.32 Pg C (17-39% Prochlorococcus, 12-15% Synechococcus and 49-69% picoeukaryotes), with an intermediate/best estimate of 0.74 Pg C. Future efforts in this area of research should focus on reporting calibrated cell size and collecting data in undersampled regions. http://doi.pangaea.de/10.1594/PANGAEA.777385

  17. Picophytoplankton biomass distribution in the global ocean

    NASA Astrophysics Data System (ADS)

    Buitenhuis, E. T.; Li, W. K. W.; Vaulot, D.; Lomas, M. W.; Landry, M.; Partensky, F.; Karl, D. M.; Ulloa, O.; Campbell, L.; Jacquet, S.; Lantoine, F.; Chavez, F.; Macias, D.; Gosselin, M.; McManus, G. B.

    2012-04-01

    The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s, during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1° spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins. The average picophytoplankton biomass is 12 ± 22 μg C l-1 or 1.9 g C m-2. We estimate a total global picophytoplankton biomass of 0.53-0.74 Pg C (17-39% Prochlorococcus, 12-15% Synechococcus and 49-69% picoeukaryotes). Future efforts in this area of research should focus on reporting calibrated cell size, and collecting data in undersampled regions.

  18. The Global S$_1$ Ocean Tide

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G. D.

    2003-01-01

    The small S$_1$ ocean tide is caused primarily by diurnal atmospheric pressure loading. Its excitation is therefore unlike any other diurnal tide. The global character of $S-1$ is here determined by numerical modeling and by analysis of Topex/Poseidon satellite altimeter data. The two approaches yield reasonably consistent results, and large ( $ greater than $l\\cm) amplitudes in several regions are further confirmed by comparison with coastal tide gauges. Notwithstanding their excitation differences, S$-1$ and other diurnal tides are found to share several common features, such as relatively large amplitudes in the Arabian Sea, the Sea of Okhotsk, and the Gulf of Alaska. The most noticeable difference is the lack of an S$-1$ Antarctic Kelvin wave. These similarities and differences can be explained in terms of the coherences between near-diurnal oceanic normal modes and the underlying tidal forcings. While gravitational diurnal tidal forces excite primarily a 28-hour Antarctic-Pacific mode, the S$_1$ air tide excites several other near-diurnal modes, none of which has large amplitudes near Antarctica.

  19. Global deep ocean oxygenation by enhanced ventilation in the Southern Ocean under long-term global warming

    NASA Astrophysics Data System (ADS)

    Yamamoto, A.; Abe-Ouchi, A.; Shigemitsu, M.; Oka, A.; Takahashi, K.; Ohgaito, R.; Yamanaka, Y.

    2015-10-01

    Global warming is expected to decrease ocean oxygen concentrations by less solubility of surface ocean and change in ocean circulation. The associated expansion of the oxygen minimum zone would have adverse impacts on marine organisms and ocean biogeochemical cycles. Oxygen reduction is expected to persist for a thousand years or more, even after atmospheric carbon dioxide stops rising. However, long-term changes in ocean oxygen and circulation are still unclear. Here we simulate multimillennium changes in ocean circulation and oxygen under doubling and quadrupling of atmospheric carbon dioxide, using a fully coupled atmosphere-ocean general circulation model and an offline biogeochemical model. In the first 500 years, global oxygen concentration decreases, consistent with previous studies. Thereafter, however, the oxygen concentration in the deep ocean globally recovers and overshoots at the end of the simulations, despite surface oxygen decrease and weaker Atlantic meridional overturning circulation. This is because, after the initial cessation, the recovery and overshooting of deep ocean convection in the Weddell Sea enhance ventilation and supply oxygen-rich surface waters to deep ocean. Another contributor to deep ocean oxygenation is seawater warming, which reduces the export production and shifts the organic matter remineralization to the upper water column. Our results indicate that the change in ocean circulation in the Southern Ocean potentially drives millennial-scale oxygenation in deep ocean, which is opposite to the centennial-scale global oxygen reduction and general expectation.

  20. Role of winds in estimation of ocean heat storage anomaly using satellite data

    NASA Astrophysics Data System (ADS)

    Yan, Xiao-Hai; Pan, Jiayi; Jo, Young-Heon; He, Ming-Xia; Liu, W. Timothy; Jiang, Lide

    2004-03-01

    The heat storage anomaly of the upper ocean can be estimated using altimeter data, based on the thermal dynamics equation. In this study, we analyzed both nonthermal and thermal steric height measured by altimetry, and removed nonthermal steric height from altimeter measurements to calculate the heat storage anomaly from thermal steric height alone in the global oceans, but with a focus on the Pacific Ocean. After examining nonthermal steric height (salinity, waves, and wind), we believe that wind stress is a major component to the change in sea surface height. Blended TOPEX/Poseidon and ERS-1/2 altimeter 1° × 1° sea surface height anomaly from January 1993 to October 2000 were used to calculation of the heat storage anomaly. In addition, we used expendable bathythermograph (XBT) data to the global oceans to determine a reference heat storage, from which the altimeter estimation of the heat storage was compared. The wind stress curls, from scatterometer data obtained from January 1993 to October 2000, were used for analyzing the wind effects on sea surface height variation. The correlation coefficients between heat storage from altimeter data (HAlt') and that from the XBT (HXBT') are larger than 0.6 in the global oceans, except in the regions of 20°N in the eastern Pacific, the eastern tropical Pacific, the tropical Atlantic, and the western tropical Indian Ocean. The root mean square (RMS) of the differences (HAlt' - HXBT') has large values in the Gulf Stream and the Kuroshio Extension regions as well as the eastern and western tropical Pacific, and eastern Indian Ocean. The wind-induced sea surface height variation exhibits strong annual and interannual cycles, so the empirical orthogonal function (EOF) method was employed to extract the cycles. The annual cycle has two modes, whereas the interannual cycle is characterized by El Niño events. Wind stress can affect the estimation of the heat storage through mechanisms derived from quasi-geostrophic and

  1. Global terrestrial water storage capacity and flood potential using GRACE

    NASA Astrophysics Data System (ADS)

    Reager, J. T.; Famiglietti, J. S.

    2009-12-01

    Terrestrial water storage anomaly from the Gravity Recovery and Climate Experiment (GRACE) and precipitation observations from the Global Precipitation Climatology Project (GPCP) are applied at the regional scale to show the usefulness of a remotely sensed, storage-based flood potential method. Over the GRACE record length, instances of repeated maxima in water storage anomaly that fall short of variable maxima in cumulative precipitation suggest an effective storage capacity for a given region, beyond which additional precipitation must be met by marked increases in runoff or evaporation. These saturation periods indicate the possible transition to a flood-prone situation. To investigate spatially and temporally variable storage overflow, a monthly storage deficit variable is created and a global map of effective storage capacity is presented for possible use in land surface models. To highlight a flood-potential application, we design a monthly global flood index and compare with Dartmouth Flood Observatory flood maps.

  2. Global data products help assess changes to ocean carbon sink

    SciTech Connect

    Bakker, Dorothee C. E.; Pfeil, Benjamin; Olsen, Are; Sabine, Christopher L.; Metzl, Nicolas; Hankin, Steven; Koyuk, Heather; Kozyr, Alex; Malczyk, Jeremy; Manke, Ansley; Telszewski, Maciej

    2012-03-20

    Net oceanic uptake of the greenhouse gas carbon dioxide (CO2) reduces global warming but also leads to ocean acidification [Intergovernmental Panel on Climate Change (IPCC), 2007]. Understanding and predicting changes in the ocean carbon sink are critical to assessments of future climate change. Surface water CO2 measurements suggest large year-to-year variations in oceanic CO2 uptake for several regions [Doney et al., 2009]. However, there is much debate on whether these changes are cyclical or indicative of long-term trends. Sustained, globally coordinated observations of the surface ocean carbon cycle and systematic handling of such data are essential for assessing variation and trends in regional and global ocean carbon uptake, information necessary for accurate estimates of global and national carbon budgets.

  3. Global View of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    2000-01-01

    together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images.

    'We can see large cracks in the ice cover, where most ice grows, ' said Kwok. 'These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles),' Kwok continued. 'If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean. '

    Scientists believe this is one of the most significant breakthroughs in the last two decades of ice research. 'We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change, ' said Kwok.

    Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task.

    'This is truly a major innovation in terms of the quantities of data being processed and the novelty of the methods being used, ' said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks.

    The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. JPL manages the Sea Ice Thickness Derived From High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced changes affect our global environment.

  4. Global View of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    2000-01-01

    together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images.

    'We can see large cracks in the ice cover, where most ice grows, ' said Kwok. 'These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles),' Kwok continued. 'If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean. '

    Scientists believe this is one of the most significant breakthroughs in the last two decades of ice research. 'We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change, ' said Kwok.

    Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task.

    'This is truly a major innovation in terms of the quantities of data being processed and the novelty of the methods being used, ' said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks.

    The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. JPL manages the Sea Ice Thickness Derived From High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced changes affect our global environment.

  5. Monitoring changes in upper ocean heat storage from satellites

    NASA Technical Reports Server (NTRS)

    Miller, J. R.

    1978-01-01

    A one-dimensional model of the upper ocean mixed-layer was developed to determine how the parameters which can be measured from satellites affect the development of the layer. The results show that the form of the dissipation term is important in achieving cyclic annual states, that the layer deepending rate depends on the averaging period for the surface heat flux and wind stress, that wind direction, as well as magnitude, can affect the deepening rate and that horizontal advective effects cannot simply be superimposed on the model results. An algorithm is given which uses satellite derived wind stress and sea surface temperature data to predict real time changes in upper ocean heat storage during the cooling seasons.

  6. Atmospheric and oceanographic research review, 1978. [global weather, ocean/air interactions, and climate

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Research activities related to global weather, ocean/air interactions, and climate are reported. The global weather research is aimed at improving the assimilation of satellite-derived data in weather forecast models, developing analysis/forecast models 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 model the processes that determine the general circulation of the oceans, focusing on those processes that affect sea surface temperature and oceanic heat storage, which are the oceanographic variables with the greatest influence on climate. The climate research objective is to support the development and effective utilization of space-acquired data systems in climate forecast models and to conduct sensitivity studies to determine the affect of lower boundary conditions on climate and predictability studies to determine which global climate features can be modeled either deterministically or statistically.

  7. Arctic Ocean basin liquid freshwater storage trend 1992-2012

    NASA Astrophysics Data System (ADS)

    Rabe, B.; Karcher, M.; Kauker, F.; Schauer, U.; Toole, J. M.; Krishfield, R. A.; Pisarev, S.; Kikuchi, T.; Su, J.

    2014-02-01

    Freshwater in the Arctic Ocean plays an important role in the regional ocean circulation, sea ice, and global climate. From salinity observed by a variety of platforms, we are able, for the first time, to estimate a statistically reliable liquid freshwater trend from monthly gridded fields over all upper Arctic Ocean basins. From 1992 to 2012 this trend was 600±300 km3 yr-1. A numerical model agrees very well with the observed freshwater changes. A decrease in salinity made up about two thirds of the freshwater trend and a thickening of the upper layer up to one third. The Arctic Ocean Oscillation index, a measure for the regional wind stress curl, correlated well with our freshwater time series. No clear relation to Arctic Oscillation or Arctic Dipole indices could be found. Following other observational studies, an increased Bering Strait freshwater import to the Arctic Ocean, a decreased Davis Strait export, and enhanced net sea ice melt could have played an important role in the freshwater trend we observed.

  8. Effects of ocean grid resolution on tropical cyclone-induced upper ocean responses using a global ocean general circulation model

    NASA Astrophysics Data System (ADS)

    Li, Hui; Sriver, Ryan L.

    2016-11-01

    Tropical cyclones (TCs) have the potential to influence regional and global climate through interactions with the upper ocean. Here we present results from a suite of ocean-only model experiments featuring the Community Earth System Model, in which we analyze the effect of tropical cyclone wind forcing on the global ocean using three different horizontal ocean grid resolutions (3°, 1°, and 0.1°). The ocean simulations are forced with identical atmospheric inputs from the Coordinated Ocean-Ice Reference Experiments version 2 (COREv2) normal year forcing conditions, featuring global blended TC winds from a fully coupled CESM simulation with a 25 km atmosphere. The simulated TC climatology shows good agreement with observational estimates of annual TC statistics, including annual frequency, intensity distributions, and geographic distributions. Each ocean simulation is composed of a 5 year spin-up with COREv2 normal year forcing, followed by 18 months with blended TC winds. In addition, we conduct corresponding control simulations for each grid resolution configuration without blended TC winds. We find that ocean horizontal and vertical grid resolutions affect TC-induced heat and momentum fluxes, poststorm cold wake features, and ocean subsurface temperature profiles. The responses are amplified for smaller grid spacing. Moreover, analyses show that the annually accumulated TC-induced ocean heat uptake is also sensitive to ocean grid resolution, which may have important implications for modeled ocean heat budgets and variability.

  9. Eddy-Resolving Global Ocean Prediction

    DTIC Science & Technology

    2009-07-01

    key observing system for mapping ocean eddies and current meanders, but sea surface temperature, temperature and salinity profiles, and atmospheric...for mapping ocean eddies and current meanders, but sea surface temperature, temperature and salinity profiles, and atmospheric forcing arc also...fronts, eddies, Rossby waves, and the associated temperature, salinity, currents, and sea surface height (SSH). Only since the turn of the century

  10. Beyond peak reservoir storage? A global estimate of declining water storage capacity in large reservoirs

    NASA Astrophysics Data System (ADS)

    Wisser, Dominik; Frolking, Steve; Hagen, Stephen; Bierkens, Marc F. P.

    2013-09-01

    Water storage is an important way to cope with temporal variation in water supply and demand. The storage capacity and the lifetime of water storage reservoirs can be significantly reduced by the inflow of sediments. A global, spatially explicit assessment of reservoir storage loss in conjunction with vulnerability to storage loss has not been done. We estimated the loss in reservoir capacity for a global data set of large reservoirs from 1901 to 2010, using modeled sediment flux data. We use spatially explicit population data sets as a proxy for storage demand and calculate storage capacity for all river basins globally. Simulations suggest that the net reservoir capacity is declining as a result of sedimentation (˜5% compared to the installed capacity). Combined with increasing need for storage, these losses challenge the sustainable management of reservoir operation and water resources management in many regions. River basins that are most vulnerable include those with a strong seasonal flow pattern and high population growth rates such as the major river basins in India and China. Decreasing storage capacity globally suggests that the role of reservoir water storage in offsetting sea-level rise is likely weakening and may be changing sign.

  11. Accelerated Prediction of the Polar Ice and Global Ocean (APPIGO)

    DTIC Science & Technology

    2015-09-30

    circulation . In the southern ocean , POP-CESM has an overall higher ice thickness than in the HYCOM simulations, with maximum in the Weddell and Ross Seas...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Accelerated Prediction of the Polar Ice and Global Ocean ...APPIGO) Eric Chassignet Center for Ocean -Atmosphere Prediction Studies (COAPS) Florida State University, PO Box 3062840 Tallahassee, FL 32306

  12. Understanding Global Climate Change with Ocean Acoustic Tomography and Models,

    DTIC Science & Technology

    1992-11-01

    these scales in the global oceans in real-time. The cost for these measurements is projected to be less than the costs of mapping temperature and other variables in the atmosphere ( Spiesberger , 1992). (MM)

  13. Ocean Tides. Part 1. Global Ocean Tidal Equations

    DTIC Science & Technology

    1980-01-01

    tidal loading found by Estes (1977). Following Thomson (1868), Darwin (1883), Doodson (1921), and Cartwright and Taylor (1971), the primary...Prandtl Number Fluid. Journal of Fluid Mechan- ics, 47, p. 305. Cartwright , D. E., and Tayler, R. J., 1971, New Computations of the Tide-Generating...Potential. Geophys. J. Roy. Astr. Soc., 23, p. 45. Cox, M. D., 1970. A Mathematical Model of the Indian Ocean. Deep- Sea Research, 17, p. 45. Darwin , G

  14. Acoustic Monitoring of Global Ocean Variability

    DTIC Science & Technology

    1993-10-10

    known oceanic physics and dynamics, and ( b ) the other observational programs intended to examine related aspects of the same problem. Descriptions...characterization, of the order of 4% source duty cycles will extend for up to one year followed b ; a lower, long-term sampling cycle, characteristic of...Wunsch, and D. B . Haidvogel, 1992. Assimilation of sea surface topography into an ocean circulation model using a steady-state smoother. Submitted for

  15. Global Earth Response to Loading by Ocean Tide Models

    NASA Technical Reports Server (NTRS)

    Estes, R. H.; Strayer, J. M.

    1979-01-01

    Mathematical and programming techniques to numerically calculate Earth response to global semidiurnal and diurnal ocean tide models were developed. Global vertical crustal deformations were evaluated for M sub 2, S sub 2, N sub 2, K sub 2, K sub 1, O sub 1, and P sub 1 ocean tide loading, while horizontal deformations were evaluated for the M sub 2 tidal load. Tidal gravity calculations were performed for M sub 2 tidal loads, and strain tensor elements were evaluated for M sub 2 loads. The M sub 2 solution used for the ocean tide included the effects of self-gravitation and crustal loading.

  16. A Real-time Operational Global Ocean Forecast System

    NASA Astrophysics Data System (ADS)

    Mehra, A.; Rivin, I.

    2010-12-01

    Efforts are ongoing to implement a real-time operational global ocean forecast system at NCEP/NWS/NOAA. This system will be based on an eddy resolving 1/12 degree global HYCOM model (Chassignet et al., 2009) and is part of a larger national backbone capability of ocean modeling at NWS in a strong partnership with US Navy. Long term plans include coupling it to Hurricane prediction models (eg. HWRF) and for providing ocean component for seasonal to interannual climate forecast systems (eg. CFS). The forecast system will run once a day and produce a week long forecast using the daily initialization fields produced at NAVOCEANO using NCODA, a 3D multi-variate data assimilation methodology (Cummings, 2005). The operational ocean model configuration has 32 hybrid layers and a horizontal grid size of (4500 x 3298). It is forced with surface fluxes from the operational Global Forecast System (GFS) fields. References: Chassignet, E.P., H.E. Hurlburt, E.J. Metzger, O.M. Smedstad, J. Cummings, G.R. Halliwell, R. Bleck, R. Baraille, A.J. Wallcraft, C. Lozano, H.L. Tolman, A. Srinivasan, S. Hankin, P. Cornillon, R. Weisberg, A. Barth, R. He, F. Werner, and J. Wilkin, 2009. U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM). Oceanography, 22(2), 64-75. Cummings, J.A., 2005: Operational multivariate ocean data assimilation. Quart. J. Royal Met. Soc., Part C, 131(613), 3583-3604.

  17. GLobal Ocean Data Analysis Project (GLODAP): Data and Analyses

    DOE Data Explorer

    Sabine, C. L.; Key, R. M.; Feely, R. A.; Bullister, J. L.; Millero, F. J.; Wanninkhof, R.; Peng, T. H.; Kozyr, A.

    The GLobal Ocean Data Analysis Project (GLODAP) is a cooperative effort to coordinate global synthesis projects funded through NOAA, DOE, and NSF as part of the Joint Global Ocean Flux Study - Synthesis and Modeling Project (JGOFS-SMP). Cruises conducted as part of the World Ocean Circulation Experiment (WOCE), JGOFS, and the NOAA Ocean-Atmosphere Exchange Study (OACES) over the decade of the 1990s have created an important oceanographic database for the scientific community investigating carbon cycling in the oceans. The unified data help to determine the global distributions of both natural and anthropogenic inorganic carbon, including radiocarbon. These estimates provide an important benchmark against which future observational studies will be compared. They also provide tools for the direct evaluation of numerical ocean carbon models. GLODAP information available through CDIAC includes gridded and bottle data, a live server, an interactive atlas that provides access to data plots, and other tools for viewing and interacting with the data. [from http://cdiac.esd.ornl.gov/oceans/glodap/Glopintrod.htm](Specialized Interface)

  18. The role of clouds and oceans in global greenhouse warming

    SciTech Connect

    Hoffert, M.I.

    1992-12-01

    During the past three years we have conducted several studies using models and a combination of satellite data, in situ meteorological and oceanic data, and paleoclimate reconstructions, under the DoE program, Quantifying the Link Between Change in Radiative Balance and Atmospheric Temperature''. Our goals were to investigate effects of global cloudiness variations on global climate and their implications for cloud feedback and continue development and application of NYU transient climate/ocean models, with emphasis on coupled effects of greenhouse warming and feedbacks by both the clouds and oceans. Our original research plan emphasized the use of cloud, surface temperature and ocean data sets interpreted by focused climate/ocean models to develop a cloud radiative forcing scenario for the past 100 years and to assess the transient climate response; to narrow key uncertainties in the system; and to identify those aspects of the climate system most likely to be affected by greenhouse warming over short, medium and long time scales.

  19. Southern ocean: Its involvement in global change. (Reannouncement with new availability information)

    SciTech Connect

    Gordon, A.L.

    1990-06-15

    The Southern Ocean is the site of considerable water mass formation which cools and ventilates the modern world ocean. At the polar front zone, formation of cool, low salinity water sinks and spreads northward at intermediate depths limiting the downward penetration of the thermocline. Within the seasonal sea ice zone and along the margins of Antarctica, convection injects very cold oxygenated water into the deep and bottom ocean. These conditions developed as Antarctica shifted into its present configuration and grew a persistent glacial ice sheet, about 14 million years ago. The potential of the Southern Ocean to ventilate the deep and bottom ocean layers is related to occurrence of polynyas that form within the winter sea ice cover. Global climate changes would be expected to alter the polynya size and frequency. Under greenhouse-induced warming offshore polynyas may become less common as the static stability of the Southern Ocean mixed layer increases. This would diminish the Southern Ocean`s cooling influence on the deep layers of the world ocean, resulting in a warmer deep ocean. The fate of coastal polynyas is less clear. It is likely that they would continue at close to their present form providing a setting conducive to Antarctic Bottom Water formation. Within the polar front zone, global warming is expected to create lower salinity though slightly cooler surface water. A reduction in the salt input to the Antarctic Intermediate Water would inject it into a shallower horizon at the thermocline base, further limiting the thickness of the thermocline. Less heat storage in the thermocline would tend to counteract the proposed deep ocean warming.

  20. Global observations of ocean Rossby waves

    SciTech Connect

    Chelton, D.B.; Schlax, M.G.

    1996-04-12

    Rossby waves play a critical role in the transient adjustment of ocean circulation to changes in large-scale atmospheric forcing. The TOPEX/POSEIDON satellite altimeter has detected Rossby waves throughout much of the world ocean from sea level signals with {approx_lt} 10-centimeters amplitude and {approx_lt} 500-kilometer wavelength. Outside of the tropics Rossby waves are abruptly amplified by major topographic features. Analysis of 3 years of data reveals discrepancies between observed and theoretical Rossby wave phase speeds that indicate that the standard theory for free, linear Rossby waves in an incomplete description of the observed waves. 32 refs., 5 figs.

  1. Global coupled sea ice-ocean state estimation

    NASA Astrophysics Data System (ADS)

    Fenty, Ian; Menemenlis, Dimitris; Zhang, Hong

    2017-08-01

    We study the impact of synthesizing ocean and sea ice concentration data with a global, eddying coupled sea ice-ocean configuration of the Massachusetts Institute of Technology general circulation model with the goal of reproducing the 2004 three-dimensional time-evolving ice-ocean state. This work builds on the state estimation framework developed in the Estimating the Circulation and Climate of the Ocean consortium by seeking a reconstruction of the global sea ice-ocean system that is simultaneously consistent with (1) a suite of in situ and remotely-sensed ocean and ice data and (2) the physics encoded in the numerical model. This dual consistency is successfully achieved here by adjusting only the model's initial hydrographic state and its atmospheric boundary conditions such that misfits between the model and data are minimized in a least-squares sense. We show that synthesizing both ocean and sea ice concentration data is required for the model to adequately reproduce the observed details of the sea ice annual cycle in both hemispheres. Surprisingly, only modest adjustments to our first-guess atmospheric state and ocean initial conditions are necessary to achieve model-data consistency, suggesting that atmospheric reanalysis products remain a leading source of errors for sea ice-ocean model hindcasts and reanalyses. The synthesis of sea ice data is found to ameliorate misfits in the high latitude ocean, especially with respect to upper ocean stratification, temperature, and salinity. Constraining the model to sea ice concentration modestly reduces ICESat-derived Arctic ice thickness errors by improving the temporal and spatial evolution of seasonal ice. Further increases in the accuracy of global sea ice thickness in the model likely require the direct synthesis of sea ice thickness data.

  2. Global coupled sea ice-ocean state estimation

    NASA Astrophysics Data System (ADS)

    Fenty, Ian; Menemenlis, Dimitris; Zhang, Hong

    2015-09-01

    We study the impact of synthesizing ocean and sea ice concentration data with a global, eddying coupled sea ice-ocean configuration of the Massachusetts Institute of Technology general circulation model with the goal of reproducing the 2004 three-dimensional time-evolving ice-ocean state. This work builds on the state estimation framework developed in the Estimating the Circulation and Climate of the Ocean consortium by seeking a reconstruction of the global sea ice-ocean system that is simultaneously consistent with (1) a suite of in situ and remotely-sensed ocean and ice data and (2) the physics encoded in the numerical model. This dual consistency is successfully achieved here by adjusting only the model's initial hydrographic state and its atmospheric boundary conditions such that misfits between the model and data are minimized in a least-squares sense. We show that synthesizing both ocean and sea ice concentration data is required for the model to adequately reproduce the observed details of the sea ice annual cycle in both hemispheres. Surprisingly, only modest adjustments to our first-guess atmospheric state and ocean initial conditions are necessary to achieve model-data consistency, suggesting that atmospheric reanalysis products remain a leading source of errors for sea ice-ocean model hindcasts and reanalyses. The synthesis of sea ice data is found to ameliorate misfits in the high latitude ocean, especially with respect to upper ocean stratification, temperature, and salinity. Constraining the model to sea ice concentration modestly reduces ICESat-derived Arctic ice thickness errors by improving the temporal and spatial evolution of seasonal ice. Further increases in the accuracy of global sea ice thickness in the model likely require the direct synthesis of sea ice thickness data.

  3. Toward an Internal Gravity Wave Spectrum in Global Ocean Models

    DTIC Science & Technology

    2015-05-14

    14 MAY 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Toward an Internal Gravity Wave Spectrum in Global...resolution global ocean models forced by atmospheric fields and tides are beginning to display realistic internal gravity wave spectra, especially as

  4. Global Average Upper Ocean Temperature Response To Changing Solar Irradiance: Exciting The Internal Decadal Mode

    NASA Astrophysics Data System (ADS)

    White, W. B.; Dettinger, M. D.; Cayan, D. R.; White, Warren B.; Dettinger, Michael D.; Cayan, Daniel R.

    longwave radiation to space. Graham, N.E. and W.B. White, 1988. The El Niño cycle: a natural oscillator of the Pacific ocean-atmosphere system. Science, 240, 1293-1302. White, W.B., J. Lean, D.R. Cayan, and M. Dettinger, 1997. A response of global upper ocean temperature to changing solar irradiance. J. Geophys. Res., 102, 3255- 3266. White, W.B. and D.R. Cayan, 1998. Quasi-periodicity and global symmetries in interdecadal upper ocean temperature variability. J. Geophys. Res., 103, 21335- 21354. White, W.B., D.R. Cayan and J. Lean, 1998. Global upper ocean heat storage response to radiative forcing from changing solar irradiance and increasing greenhouse gas/aerosol concentrations. J. Geophys. Res., 103, 21355-21366. White, W.B., D.R. Cayan, M.D. Dettinger, and G. Auad, 2000a. Sources of global warming in upper ocean temperature during El Niño. J. Geophys.Res., (in press). White, W.B., . Y.M. Tourre, B. Rajagopalan, Y. Kushnir, M. Barlow, 2000b. A delayed action oscillator mechanism shared by biennial, interannual, and decadal signals in the Pacific basin. J. Climate (in review).

  5. Tsunami Speed Variations in Density-stratified Compressible Global Oceans

    NASA Astrophysics Data System (ADS)

    Watada, S.

    2013-12-01

    Recent tsunami observations in the deep ocean have accumulated unequivocal evidence that tsunami traveltime delays compared with the linear long-wave tsunami simulations occur during tsunami propagation in the deep ocean. The delay is up to 2% of the tsunami traveltime. Watada et al. [2013] investigated the cause of the delay using the normal mode theory of tsunamis and attributed the delay to the compressibility of seawater, the elasticity of the solid earth, and the gravitational potential change associated with mass motion during the passage of tsunamis. Tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth-variable sound speeds and density gradients. For a 4-km deep ocean, the total tsunami speed reduction is 0.45% compared with incompressible homogeneous seawater; two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression. Tsunami speeds are computed for global ocean density and sound speed profiles and characteristic structures are discussed. Tsunami speed reductions are proportional to ocean depth with small variations, except for in warm Mediterranean seas. The impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of trans-oceanic tsunamis. Data locations where a vertical ocean profile deeper than 2500 m is available in World Ocean Atlas 2009. The dark gray area indicates the Pacific Ocean defined in WOA09. a) Tsunami speed variations. Red, gray and black bars represent global, Pacific, and Mediterranean Sea, respectively. b) Regression lines of the tsunami velocity reduction for all oceans. c)Vertical ocean profiles at grid points indicated by the stars in Figure 1.

  6. Global root zone storage capacity from satellite-based evaporation

    NASA Astrophysics Data System (ADS)

    Wang-Erlandsson, Lan; Bastiaanssen, Wim G. M.; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel B.; van Dijk, Albert I. J. M.; Guerschman, Juan P.; Keys, Patrick W.; Gordon, Line J.; Savenije, Hubert H. G.

    2016-04-01

    This study presents an "Earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale independent. In contrast to a traditional look-up table approach, our method captures the variability in root zone storage capacity within land cover types, including in rainforests where direct measurements of root depths otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM (Simple Terrestrial Evaporation to Atmosphere Model) improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. Our results suggest that several forest types are able to create a large storage to buffer for severe droughts (with a very long return period), in contrast to, for example, savannahs and woody savannahs (medium length return period), as well as grasslands, shrublands, and croplands (very short return period). The presented method to estimate root zone storage capacity eliminates the need for poor resolution soil and rooting depth data that form a limitation for achieving progress in the global land surface modelling community.

  7. Sources of global warming of the upper ocean on decadal period scales

    NASA Astrophysics Data System (ADS)

    White, Warren B.; Dettinger, Michael D.; Cayan, Daniel R.

    2003-08-01

    Recent studies find global climate variability in the upper ocean and lower atmosphere during the twentieth century dominated by quasi-biennial, interannual, quasi-decadal and interdecadal signals. The quasi-decadal signal in upper ocean temperature undergoes global warming/cooling of ˜0.1°C, similar to that occurring with the interannual signal (i.e., El Niño-Southern Oscillation), both signals dominated by global warming/cooling in the tropics. From the National Centers for Environmental Prediction troposphere reanalysis and Scripps Institution of Oceanography upper ocean temperature reanalysis we examine the quasi-decadal global tropical diabatic heat storage (DHS) budget from 1975 to 2000. We find the anomalous DHS warming tendency of 0.3-0.9 W m-2 driven principally by a downward global tropical latent-plus-sensible heat flux anomaly into the ocean, overwhelming the tendency by weaker upward shortwave-minus-longwave heat flux anomaly to drive an anomalous DHS cooling tendency. During the peak quasi-decadal warming the estimated dissipation of DHS anomaly of 0.2-0.5 W m-2 into the deep ocean and a similar loss to the overlying atmosphere through air-sea heat flux anomaly are balanced by a decrease in the net poleward Ekman heat advection out of the tropics of 0.4-0.7 W m-2. This scenario is nearly the opposite of that accounting for global tropical warming during the El Niño. These diagnostics confirm that even though the global quasi-decadal signal is phase-locked to the 11-year signal in the Sun's surface radiative forcing of ˜0.1 W m-2, the anomalous global tropical DHS tendency cannot be driven by it directly.

  8. Sources of global warming of the upper ocean on decadal period scales

    USGS Publications Warehouse

    White, Warren B.; Dettinger, M.D.; Cayan, D.R.

    2003-01-01

    Recent studies find global climate variability in the upper ocean and lower atmosphere during the twentieth century dominated by quasi-biennial, interannual, quasi-decadal and interdecadal signals. The quasi-decadal signal in upper ocean temperature undergoes global warming/cooling of ???0.1??C, similar to that occuring with the interannual signal (i.e., El Nin??o-Southern Oscillation), both signals dominated by global warming/cooling in the tropics. From the National Centers for Environmental Prediction troposphere reanalysis and Scripps Institution of Oceanography upper ocean temperature reanalysis we examine the quasi-decadal global tropical diabetic heat storage (DHS) budget from 1975 to 2000. We find the anomalous DHS warming tendency of 0.3-0.9 W m-2 driven principally by a downward global tropical latent-plus-sensible heat flux anomaly into the ocean, overwhelming the tendency by weaker upward shortwave-minus-longwave heat flux anomaly to drive an anomalous DHS cooling tendency. During the peak quasi-decadal warming the estimated dissipation of DHS anomaly of 0.2-0.5 W m-2 into the deep ocean and a similar loss to the overlying atmosphere through air-sea heat flux anomaly are balanced by a decrease in the net poleward Ekman heat advection out of the tropics of 0.4-0.7 W m-2. This scenario is nearly the opposite of that accounting for global tropical warming during the El Nin??o. These diagnostics confirm that even though the global quasi-decadal signal is phase-locked to the 11-year signal in the Sun's surface radiative forcing of ???0.1 W m-2, the anomalous global tropical DHS tendency cannot be driven by it directly.

  9. Sharing Data in the Global Ocean Observing System (Invited)

    NASA Astrophysics Data System (ADS)

    Lindstrom, E. J.; McCurdy, A.; Young, J.; Fischer, A. S.

    2010-12-01

    We examine the evolution of data sharing in the field of physical oceanography to highlight the challenges now before us. Synoptic global observation of the ocean from space and in situ platforms has significantly matured over the last two decades. In the early 1990’s the community data sharing challenges facing the World Ocean Circulation Experiment (WOCE) largely focused on the behavior of individual scientists. Satellite data sharing depended on the policy of individual agencies. Global data sets were delivered with considerable delay and with enormous personal sacrifice. In the 2000’s the requirements for global data sets and sustained observations from the likes of the U.N. Framework Convention on Climate Change have led to data sharing and cooperation at a grander level. It is more effective and certainly more efficient. The Joint WMO/IOC Technical Commission on Oceanography and Marine Meteorology (JCOMM) provided the means to organize many aspects of data collection and data dissemination globally, for the common good. In response the Committee on Earth Observing Satellites organized Virtual Constellations to enable the assembly and sharing of like kinds of satellite data (e.g., sea surface topography, ocean vector winds, and ocean color). Individuals in physical oceanography have largely adapted to the new rigors of sharing data for the common good, and as a result of this revolution new science has been enabled. Primary obstacles to sharing have shifted from the individual level to the national level. As we enter into the 2010’s the demands for ocean data continue to evolve with an expanded requirement for more real-time reporting and broader disciplinary coverage, to answer key scientific and societal questions. We are also seeing the development of more numerous national contributions to the global observing system. The drivers for the establishment of global ocean observing systems are expanding beyond climate to include biological and

  10. Ecogenomics and potential biogeochemical impacts of globally abundant ocean viruses.

    PubMed

    Roux, Simon; Brum, Jennifer R; Dutilh, Bas E; Sunagawa, Shinichi; Duhaime, Melissa B; Loy, Alexander; Poulos, Bonnie T; Solonenko, Natalie; Lara, Elena; Poulain, Julie; Pesant, Stéphane; Kandels-Lewis, Stefanie; Dimier, Céline; Picheral, Marc; Searson, Sarah; Cruaud, Corinne; Alberti, Adriana; Duarte, Carlos M; Gasol, Josep M; Vaqué, Dolors; Bork, Peer; Acinas, Silvia G; Wincker, Patrick; Sullivan, Matthew B

    2016-09-29

    Ocean microbes drive biogeochemical cycling on a global scale. However, this cycling is constrained by viruses that affect community composition, metabolic activity, and evolutionary trajectories. Owing to challenges with the sampling and cultivation of viruses, genome-level viral diversity remains poorly described and grossly understudied, with less than 1% of observed surface-ocean viruses known. Here we assemble complete genomes and large genomic fragments from both surface- and deep-ocean viruses sampled during the Tara Oceans and Malaspina research expeditions, and analyse the resulting 'global ocean virome' dataset to present a global map of abundant, double-stranded DNA viruses complete with genomic and ecological contexts. A total of 15,222 epipelagic and mesopelagic viral populations were identified, comprising 867 viral clusters (defined as approximately genus-level groups). This roughly triples the number of known ocean viral populations and doubles the number of candidate bacterial and archaeal virus genera, providing a near-complete sampling of epipelagic communities at both the population and viral-cluster level. We found that 38 of the 867 viral clusters were locally or globally abundant, together accounting for nearly half of the viral populations in any global ocean virome sample. While two-thirds of these clusters represent newly described viruses lacking any cultivated representative, most could be computationally linked to dominant, ecologically relevant microbial hosts. Moreover, we identified 243 viral-encoded auxiliary metabolic genes, of which only 95 were previously known. Deeper analyses of four of these auxiliary metabolic genes (dsrC, soxYZ, P-II (also known as glnB) and amoC) revealed that abundant viruses may directly manipulate sulfur and nitrogen cycling throughout the epipelagic ocean. This viral catalog and functional analyses provide a necessary foundation for the meaningful integration of viruses into ecosystem models where they

  11. Ecogenomics and potential biogeochemical impacts of globally abundant ocean viruses

    NASA Astrophysics Data System (ADS)

    2016-09-01

    Ocean microbes drive biogeochemical cycling on a global scale. However, this cycling is constrained by viruses that affect community composition, metabolic activity, and evolutionary trajectories. Owing to challenges with the sampling and cultivation of viruses, genome-level viral diversity remains poorly described and grossly understudied, with less than 1% of observed surface-ocean viruses known. Here we assemble complete genomes and large genomic fragments from both surface- and deep-ocean viruses sampled during the Tara Oceans and Malaspina research expeditions, and analyse the resulting ‘global ocean virome’ dataset to present a global map of abundant, double-stranded DNA viruses complete with genomic and ecological contexts. A total of 15,222 epipelagic and mesopelagic viral populations were identified, comprising 867 viral clusters (defined as approximately genus-level groups). This roughly triples the number of known ocean viral populations and doubles the number of candidate bacterial and archaeal virus genera, providing a near-complete sampling of epipelagic communities at both the population and viral-cluster level. We found that 38 of the 867 viral clusters were locally or globally abundant, together accounting for nearly half of the viral populations in any global ocean virome sample. While two-thirds of these clusters represent newly described viruses lacking any cultivated representative, most could be computationally linked to dominant, ecologically relevant microbial hosts. Moreover, we identified 243 viral-encoded auxiliary metabolic genes, of which only 95 were previously known. Deeper analyses of four of these auxiliary metabolic genes (dsrC, soxYZ, P-II (also known as glnB) and amoC) revealed that abundant viruses may directly manipulate sulfur and nitrogen cycling throughout the epipelagic ocean. This viral catalog and functional analyses provide a necessary foundation for the meaningful integration of viruses into ecosystem models where

  12. Decoupling of Iron and Phosphate in the Global Ocean

    NASA Technical Reports Server (NTRS)

    Parekh, Payal

    2003-01-01

    Iron is an essential micronutrient for marine phytoplankton, limiting their growth in high nutrient, low chlorophyll regions of the ocean. I use a hierarchy of ocean circulation and biogeochemistry models to understand controls on global iron distribution. I formulate a mechanistic model of iron cycling which includes scavenging onto sinking particles and complexation with an organic ligand. The iron cycle is coupled to a phosphorus cycling model. Iron's aeolian source is prescribed. In the context of a highly idealized multi-box model scheme, the model can be brought into consistency with the relatively sparse ocean observations of iron in the oceans. This biogeochemical scheme is also implemented in a coarse resolution ocean general circulation model. This model also successfully reproduces the broad regional patterns of iron and phosphorus. In particular, the high macronutrient concentrations of the Southern Ocean result from iron limitation in the model. Due to the potential ability of iron to change the efficiency of the carbon pump in the remote Southern Ocean, I study Southern Ocean surface phosphate response to increased aeolian dust flux. My box model and GCM results suggest that a global ten fold increase in dust flux can support a phosphate drawdown of 0.25-0.5 micromolar.

  13. Decoupling of Iron and Phosphate in the Global Ocean

    NASA Technical Reports Server (NTRS)

    Parekh, Payal

    2003-01-01

    Iron is an essential micronutrient for marine phytoplankton, limiting their growth in high nutrient, low chlorophyll regions of the ocean. I use a hierarchy of ocean circulation and biogeochemistry models to understand controls on global iron distribution. I formulate a mechanistic model of iron cycling which includes scavenging onto sinking particles and complexation with an organic ligand. The iron cycle is coupled to a phosphorus cycling model. Iron's aeolian source is prescribed. In the context of a highly idealized multi-box model scheme, the model can be brought into consistency with the relatively sparse ocean observations of iron in the oceans. This biogeochemical scheme is also implemented in a coarse resolution ocean general circulation model. This model also successfully reproduces the broad regional patterns of iron and phosphorus. In particular, the high macronutrient concentrations of the Southern Ocean result from iron limitation in the model. Due to the potential ability of iron to change the efficiency of the carbon pump in the remote Southern Ocean, I study Southern Ocean surface phosphate response to increased aeolian dust flux. My box model and GCM results suggest that a global ten fold increase in dust flux can support a phosphate drawdown of 0.25-0.5 micromolar.

  14. Tides of global ice-covered oceans

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2016-08-01

    The tides of an ice-covered ocean are examined using a Cartesian representation of the elastic and fluid equations. Although unconstrained by any observations, the ocean tides of a Neoproterozoic "snowball" Earth could have been significantly larger than they are today. Time-mean tidal-residual circulations would then have been set up that are competitive with the circulation driven by geothermal heating. In any realistic configuration, the snowball Earth would have had an ice cover that is in the thin shell limit, but by permitting the ice thickness to become large, more interesting ice tidal response can be found, ones conceivably of application to bodies in the outer Solar System or hypothetical exoplanets. Little can be said concerning a reduction in tidal dissipation necessary to avoid a crisis in the history of the lunar orbit.

  15. Global Climate Change and Ocean Education

    NASA Astrophysics Data System (ADS)

    Spitzer, W.; Anderson, J.

    2011-12-01

    The New England Aquarium, collaborating with other aquariums across the country, is leading a national effort to enable aquariums and related informal science education institutions to effectively communicate the impacts of climate change and ocean acidification on marine animals, habitats and ecosystems. Our goal is to build on visitors' emotional connection with ocean animals, connect to their deeply held values, help them understand causes and effects of climate change and motivate them to embrace effective solutions. Our objectives are to: (1) Build a national coalition of aquariums and related informal education institutions collaborating on climate change education; (2) Develop an interpretive framework for climate change and the ocean that is scientifically sound, research-based, field tested and evaluated; and (3) Build capacity of aquariums to interpret climate change via training for interpreters, interactive exhibits and activities and communities of practice for ongoing support. Centers of informal learning have the potential to bring important environmental issues to the public by presenting the facts, explaining the science, connecting with existing values and interests, and motivating concern and action. Centers that work with live animals (including aquariums, zoos, nature centers, national parks, national marine sanctuaries, etc.) are unique in that they attract large numbers of people of all ages (over 140 million in the US), have strong connections to the natural, and engage many visitors who may not come with a primary interest in science. Recent research indicates that that the public expects and trusts aquariums, zoos, and museums to communicate solutions to environmental and ocean issues, and to advance ocean conservation, and that climate change is the environmental issue of most concern to the public; Ironically, however, most people do not associate climate change with ocean health, or understand the critical role that the ocean plays in

  16. Variational Data Assimilation for the Global Ocean

    DTIC Science & Technology

    2013-01-01

    profiles. One method is the Modular Ocean Data Assimilation System ( MODAS ) database, which models the time averaged co-variability of dynamic height...used in the MODAS method is derived from historical hydrographic data. Note that an upgrade to the MODAS synthetic profile capability, the Improved...ans real data constraints. MODAS does not suffer from these limitations, although MODAS may have marginal skill due to: (1) sampling limitations of

  17. Eddy Resolving Global Ocean Prediction including Tides

    DTIC Science & Technology

    2010-09-30

    best in the deep stratified ocean, pressure levels (nearly fixed depths) provide high vertical resolution in the mixed layer, and σ ­ levels (terrain...Metzger, E. J., Richman, J. G., Chassignet, E. P., Drillet, Y., Hecht, M. W., Le Galloudec, O., Shriver, J. F., Xu, X., and Zamudio , L., “Dynamical...Proceedings of the 2009 HPCMP User’s Group Conference, San Diego, CA. [published] 11 Zamudio , L., E. J. Metzger, and P. J. Hogan (2010), Gulf of California

  18. Diagnosing global ocean content changes in historically forced CMIP simulations

    NASA Astrophysics Data System (ADS)

    Gleckler, P. J.; Durack, P. J.; Stouffer, R. J.; Johnson, G. C.; Forest, C. E.

    2016-02-01

    Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0­700 m) ocean. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes evidenced in observational, modelling, and data re-analysis studies. We rely on OHC change estimates from a diverse collection of measurement systems including data from the 19th Century Challenger expedition, a multi-decadal record of ship-based in-situ mostly upper ocean measurements, the more recent near-global Argo floats profiling to intermediate (2000 m) depths, and full-depth repeated transoceanic sections. By diagnosing simulated global OHC changes in historically-forced climate models in three depth layers, we show that the current generation of climate models is broadly consistent with multi-decadal estimates of upper, intermediate (700­-2000 m) and deep (2000 m­ bottom) global OHC changes as well as with Argo-based estimates over the most recent period. Our results suggest that approximately half of the 1860­ present human-caused increases in global ocean heat content may have occurred since 1998.

  19. Influence of the Southern Ocean on the Global deep ocean stratification

    NASA Astrophysics Data System (ADS)

    Sun, S.; Eisenman, I.; Stewart, A.

    2015-12-01

    The stratification of the deep ocean plays a key role in the climate system by influencing the ocean circulation and regulating the outgassing of CO2. Previous studies have suggested that Southern Ocean processes control the global ocean stratification below the main thermocline (i.e., below ~500m). In this study, three ocean-only simulations are carried out with the Community Earth System Model (CESM1): one control simulation forced with Pre-industrial (PI) surface conditions, a second control simulation forced with Last Glacial Maximum (LGM) surface conditions, and a test simulation forced with LGM surface conditions in southern high latitudes and PI surface conditions elsewhere. We find that the test simulation does broadly reproduce the LGM density stratification of the global ocean below 2000m, but not at intermediate depths between 500m and 1500m. We propose a mechanism whereby the stratification of the intermediate-depth waters is influenced by the differing effects on the surface buoyancy distribution of fixed versus restoring aspects of the surface buoyancy forcing. This implies the Southern Ocean exerts less influence over the global deep ocean stratification than has been previously suggested, at least when considering the difference between LGM and PI climates in CESM1.

  20. Anthropogenic CO2 estimates in the Southern Ocean: storage partitioning in the different water masses.

    NASA Astrophysics Data System (ADS)

    Pardo, P. C.; Pérez, F. F.; Velo, A.; Khatiwala, S.,; Ríos, A. F.

    2012-04-01

    One of the key issues in understanding the global carbon cycle and predicting future climate change is determining the role of the Southern Ocean (SO). Approximately, more than one third of the global anthropogenic CO2 (CANT) uptake occurs in the SO (18% of the global ocean area), where the coldest source waters involved in the meridional counterclockwise overturning circulation are formed. Nevertheless, the distributions of CANT in the SO obtained from models and data-based methods present huge differences. Little storage of CANT has usually been associated with Antarctic Bottom Water (AABW) which is in contradiction with significant concentrations of CFCs observed along the continental slope and in Antarctic deep and bottom waters. The lack of accurate ocean carbon measurements could be the cause for hampering more exact CANT estimates. Besides, there is compelling evidence that sinking and ventilation in the SO is not only associated to the AABW but also to various less dense Antarctic waters located at intermediate and deep levels of the water column. In this study, data south of 45° S were chosen from GLODAP (http://cdiac.ornl.gov/oceans/glodap/Glodap_home.htm) and CARINA (http://store.pangaea.de/Projects/CARBOOCEAN/carina/index.htm) project databases (n=82792) in order to estimate CANT through different data-based methods. These methods go from the classical back-calculation methods (ΔC* and improved new ones taking into account the variability in the CO2 air-sea disequilibrium term) to TTD and TROCA methods. Results from an eOMP together with a volumetric census of the water masses within the SO serve as base for partitioning CANT storages in the more representative water masses of the SO. Thus, South Mode Water and Antarctic Intermediate Water account for the CANT storage in intermediate layers while North Atlantic Deep Waters and Circumpolar Deep Water are responsible for injecting CANT at deep layers. The contributions of AABW and Shelf Waters to the

  1. A daily global mesoscale ocean eddy dataset from satellite altimetry.

    PubMed

    Faghmous, James H; Frenger, Ivy; Yao, Yuanshun; Warmka, Robert; Lindell, Aron; Kumar, Vipin

    2015-01-01

    Mesoscale ocean eddies are ubiquitous coherent rotating structures of water with radial scales on the order of 100 kilometers. Eddies play a key role in the transport and mixing of momentum and tracers across the World Ocean. We present a global daily mesoscale ocean eddy dataset that contains ~45 million mesoscale features and 3.3 million eddy trajectories that persist at least two days as identified in the AVISO dataset over a period of 1993-2014. This dataset, along with the open-source eddy identification software, extract eddies with any parameters (minimum size, lifetime, etc.), to study global eddy properties and dynamics, and to empirically estimate the impact eddies have on mass or heat transport. Furthermore, our open-source software may be used to identify mesoscale features in model simulations and compare them to observed features. Finally, this dataset can be used to study the interaction between mesoscale ocean eddies and other components of the Earth System.

  2. The forcing, shaping and possible consequences of ocean salinity changes in the global ocean

    NASA Astrophysics Data System (ADS)

    Marsh, R.; Skliris, N.; Josey, S. A.; de Cuevas, B. A.

    2012-04-01

    The EN3 global ocean dataset (1950-2010) and various observational/reanalysis air-sea freshwater flux datasets are used to investigate long-term global ocean salinity changes in relation to changes in the surface freshwater budget. The obtained spatial pattern of multi-decadal change of surface salinity strongly resembles that of surface freshwater flux, with net evaporation/salinity increases (decreases) found in evaporation (precipitation) dominated regions. Large evaporation increase/saltening in the North Atlantic subtropical gyre and precipitation increase/freshening in the Western Pacific warm pool are highly correlated with the SST increase, suggesting an acceleration of the global hydrological cycle with possible links to the broad-scale surface warming. Moreover, results show an accentuation of the salinity contrast between Atlantic and Pacific Oceans throughout the water column as well as between the upper thermocline salinity maximum and the salinity minimum intermediate waters in both ocean basins. We also find a systematic freshening of the Southern Ocean with the decreasing salinity signal rapidly propagating via Subantarctic mode water (SAMW) at intermediate depths in the southern basins of the Atlantic, Pacific, and Indian Oceans. Using a hindcast of the global ocean circulation, water masses identified with key salinity anomalies are traced using particle trajectories to estimate the advective timescales on which salinity anomalies are spreading through the ocean interior. Based on our present understanding of the influence of salinity in the global ocean, three possible consequences of ongoing trends in the 3-D salinity field are highlighted: the extent to which positive surface salinity anomalies throughout much of the Atlantic are favourable for deep-water formation; the extent to which surface freshening in much of the tropical Pacific may inhibit surface mixed layer depth, and possible implications for SST; the dynamical influence, via

  3. Ocean Global Warming Impacts on the South America Climate

    NASA Astrophysics Data System (ADS)

    Ramos-Da-Silva, Renato

    2016-03-01

    The global Ocean-Land-Atmosphere Model (OLAM) model was used to estimate the impacts of the global oceanic warming on the climate projections for the 21st Century focusing on the South America region. This new model is able to represent simultaneously the global and regional scales using a refining grid approach for the region of interest. First, the model was run for a 31-year control period consisting on the years 1960-1990 using the monthly Sea Surface Temperature (SST) from the Atmospheric Model Intercomparison Project (AMIP) data as a driver for the ocean fluxes. Then, the model was run for the period 2010-2100 using the monthly projected SST from the Hadley Center model (HadCM3) as a driver for the oceanic changes. The model was set up with an icosahedral triangular global grid having about 250 km of grid spacing and with a refining grid resolution with the cells reaching about 32 km over the South America region. The results show an overall temperature increase mainly over the center of the Amazon basin caused by the increase of the greenhouse effect of the water vapor; a decrease on precipitation mainly over the northeast Brazil and an increase in the south and over the western Amazon region; and a major increase on the near surface wind speed. These results are similar to the global coupled models; however, OLAM has a novel type of grid that can provide the interaction between the global and regional scales simultaneously.

  4. A Global Ocean State Estimate at the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Amrhein, D. E.; Wunsch, C. I.

    2015-12-01

    Many features of Earth's climate at the Last Glacial Maximum (LGM, ca. 20,000 years ago) remain a mystery, including the role of the ocean circulation in transporting thermal energy, salinity, and other tracers. Most efforts at reconstructing the ocean state during the LGM have relied either upon integrations of general circulation models under prescribed LGM boundary conditions or the interpretation of climate proxy records without explicit physical constraints. Here we describe a global, primitive equation simulation of the LGM ocean with boundary conditions (wind, surface air temperature, and other atmospheric variables) and mixing parameters derived by a least-squares fit of an ocean general circulation model to observations of deep ocean stable isotopes and sea surface temperatures at the LGM.

  5. Marine defaunation: animal loss in the global ocean.

    PubMed

    McCauley, Douglas J; Pinsky, Malin L; Palumbi, Stephen R; Estes, James A; Joyce, Francis H; Warner, Robert R

    2015-01-16

    Marine defaunation, or human-caused animal loss in the oceans, emerged forcefully only hundreds of years ago, whereas terrestrial defaunation has been occurring far longer. Though humans have caused few global marine extinctions, we have profoundly affected marine wildlife, altering the functioning and provisioning of services in every ocean. Current ocean trends, coupled with terrestrial defaunation lessons, suggest that marine defaunation rates will rapidly intensify as human use of the oceans industrializes. Though protected areas are a powerful tool to harness ocean productivity, especially when designed with future climate in mind, additional management strategies will be required. Overall, habitat degradation is likely to intensify as a major driver of marine wildlife loss. Proactive intervention can avert a marine defaunation disaster of the magnitude observed on land.

  6. Ocean Margins Program: Closure on the global carbon cycle. Program description

    SciTech Connect

    Riches, M.R.

    1994-08-01

    The Department of Energy`s Ocean Margins Program (OMP) is designed to quantitatively assess the importance of coastal ocean systems in the global carbon cycle. Since the beginning of the Industrial Revolution, human energy-related activities have dramatically altered the global carbon cycle, and consequently, this cycle is not presently in a steady-state. To reduce major uncertainties in predicting future global environmental quality, it is imperative to understand the sources and sinks of atmospheric CO{sub 2}, the role of anthropogenic activities in disrupting the natural carbon cycle, and the effects of, and feedbacks between, these activities and the natural carbon cycle. Due to continuously increased loading of nutrients to the margins, which, globally, is related to the rate of human population growth and high population densities in coastal states, biological carbon fixation has been stimulated. Depending on the fate of the fixed carbon, this stimulation has the potential to mitigate the anthropogenically derived Co{sub 2}. Determining the factors that control the magnitude of carbon exchanges between the ocean margins and the atmosphere, and the subsequent fate of this carbon, is crucial to predicting the strength and capacity of the oceans to absorb excess anthropogenic atmospheric CO{sub 2}. The goals of the OMP are to: quantify the ecological and biogeochemical processes and mechanisms that define the cycling, flux, and storage of carbon and other biogenic elements at the land/ocean interface; identify how ocean-margin sources and sinks of carbon change in response to human activities; and determine whether continental shelves are quantitatively significant in removing atmospheric carbon dioxide and isolating it via burial in sediments or export to the interior of the open ocean.

  7. Anthropogenic CO2 estimates in the Southern Ocean: Storage partitioning in the different water masses

    NASA Astrophysics Data System (ADS)

    Pardo, Paula C.; Pérez, F. F.; Khatiwala, S.; Ríos, A. F.

    2014-01-01

    The role of the Southern Ocean (SO) remains a key issue in our understanding of the global carbon cycle and for predicting future climate change. A number of recent studies suggest that 30 to 40% of ocean uptake of anthropogenic carbon (CANT) occurs in the SO, accompanied by highly efficient transport of CANT by intermediate-depth waters out of that region. In contrast, storage of CANT in deep and bottom layers is still an open question. Significant discrepancies can be found between results from several indirect techniques and ocean models. Even though reference methodologies state that CANT concentrations in deep and bottom layers of the SO are negligible, recent results from tracer-based methods and ocean models as well as accurate measurements of 39Ar, CCl4 and CFCs along the continental slope and in the Antarctic deep and bottom waters contradict this conclusion. The role of the SO in the uptake, storage and transport of CANT has proved to be really important for the global ocean and there is a need for agreement between the different techniques. A CO2-data-based ("back-calculation") method, the CT0 method, was developed with the aim of obtaining more accurate CANT concentration and inventory estimates in the SO region (south of 45°S). Data from the GLODAP (Global Ocean Data Analysis Project) and CARINA databases were used. The CT0 method tries to reduce at least two of the main caveats attributed to the back-calculation methods: the need for a better definition of water mass mixing and, most importantly, the unsteady state of the air-sea CO2 disequilibrium (ΔCdis) term. Water mass mixing was computed on the basis of results from an extended Optimum Multi-Parametric (eOMP) analysis applied to the main water masses of the SO. Recently published parameterizations were used to obtain more reliable values of ΔCdis and also of preformed alkalinity. The variability of the ΔCdis term (δCdis) was approximated using results from an ocean carbon cycle model

  8. The timescales of global surface-ocean connectivity.

    PubMed

    Jönsson, Bror F; Watson, James R

    2016-04-19

    Planktonic communities are shaped through a balance of local evolutionary adaptation and ecological succession driven in large part by migration. The timescales over which these processes operate are still largely unresolved. Here we use Lagrangian particle tracking and network theory to quantify the timescale over which surface currents connect different regions of the global ocean. We find that the fastest path between two patches--each randomly located anywhere in the surface ocean--is, on average, less than a decade. These results suggest that marine planktonic communities may keep pace with climate change--increasing temperatures, ocean acidification and changes in stratification over decadal timescales--through the advection of resilient types.

  9. US Navy Operational Global Ocean and Arctic Ice Prediction Systems

    DTIC Science & Technology

    2014-09-01

    Wallcraft, L. Zamudio, D.S. Franklin, P.G. Posey, M.W. Phelps, P.J. Hogan , F.L. Bub, and C.J. DeHaan. 2014. US Navy operational global ocean and...from government, academia, and business ) funded by the National Ocean Partnership Program (Chassignet et al., 2009). Prediction systems were...Arctic Ocean is also important for strategic and economic reasons . Navy interest in the region has always been high but has grown over the past

  10. The self-consistent dynamic pole tide in global oceans

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1985-01-01

    The dynamic pole tide is characterized in a self-consistent manner by means of introducing a single nondifferential matrix equation compatible with the Liouville equation, modelling the ocean as global and of uniform depth. The deviations of the theory from the realistic ocean, associated with the nonglobality of the latter, are also given consideration, with an inference that in realistic oceans long-period modes of resonances would be increasingly likely to exist. The analysis of the nature of the pole tide and its effects on the Chandler wobble indicate that departures of the pole tide from the equilibrium may indeed be minimal.

  11. The timescales of global surface-ocean connectivity

    NASA Astrophysics Data System (ADS)

    Jönsson, Bror F.; Watson, James R.

    2016-04-01

    Planktonic communities are shaped through a balance of local evolutionary adaptation and ecological succession driven in large part by migration. The timescales over which these processes operate are still largely unresolved. Here we use Lagrangian particle tracking and network theory to quantify the timescale over which surface currents connect different regions of the global ocean. We find that the fastest path between two patches--each randomly located anywhere in the surface ocean--is, on average, less than a decade. These results suggest that marine planktonic communities may keep pace with climate change--increasing temperatures, ocean acidification and changes in stratification over decadal timescales--through the advection of resilient types.

  12. The self-consistent dynamic pole tide in global oceans

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1985-01-01

    The dynamic pole tide is characterized in a self-consistent manner by means of introducing a single nondifferential matrix equation compatible with the Liouville equation, modelling the ocean as global and of uniform depth. The deviations of the theory from the realistic ocean, associated with the nonglobality of the latter, are also given consideration, with an inference that in realistic oceans long-period modes of resonances would be increasingly likely to exist. The analysis of the nature of the pole tide and its effects on the Chandler wobble indicate that departures of the pole tide from the equilibrium may indeed be minimal.

  13. Distribution of diverse nitrogen fixers in the global ocean

    NASA Astrophysics Data System (ADS)

    Monteiro, F. M.; Follows, M. J.; Dutkiewicz, S.

    2010-09-01

    We employ a global three-dimensional model to simulate diverse phytoplanktonic diazotrophs (nitrogen fixers) in the oceans. In the model, the structure of the marine phytoplankton community self-assembles from a large number of potentially viable physiologies. Amongst them, analogs of Trichodesmium, unicellular diazotrophs and diatom-diazotroph associations (DDA) are successful and abundant. The simulated biogeography and nitrogen fixation rates of the modeled diazotrophs compare favorably with a compilation of published observations, which includes both traditional and molecular measurements of abundance and activity of marine diazotrophs. In the model, the diazotroph analogs occupy warm subtropical and tropical waters, with higher concentrations and nitrogen fixation rates in the tropical Atlantic Ocean and the Arabian Sea/Northern Indian Ocean, and lower values in the tropical and subtropical South Pacific Ocean. The three main diazotroph types typically co-exist in the model, although Trichodesmium analogs dominate the diazotroph population in much of the North and tropical Atlantic Ocean and the Arabian Sea, while unicellular-diazotroph analogs dominate in the South Atlantic, Pacific and Indian oceans. This pattern reflects the relative degree of nutrient limitation by iron or phosphorus. The model suggests in addition that unicellular diazotrophs could add as much new nitrogen to the global ocean as Trichodesmium.

  14. Impact of carbon storage through restoration of drylands on the global carbon cycle

    SciTech Connect

    Keller, A.A.; Goldstein, R.A.

    1998-09-01

    The authors evaluate the potential for global carbon storage in drylands as one of several policy options to reduce buildup of carbon dioxide in the atmosphere. They use the GLOCO model, a global carbon cycle model with eight terrestrial biomes that are described mechanistically in detail in terms of the biological processes that involve carbon and nitrogen cycling and the effect of temperature on these processes. GLOCO also considers low-latitude and high-latitude oceans, each divided further into a surface layer and several deeper layers, with an explicit description of biogeochemical processes occurring in each layer, and exchanges among ocean reservoirs and the atmosphere. GLOCO is used to study the transient response of actual vegetation, which is more realistic than looking at equilibrium conditions of potential vegetation. Using estimates of land suitable for restoration in woodlands, grasslands, and deserts, as well as estimates of the rate at which restoration can proceed, the authors estimate that carbon storage in these biomes can range up to 0.8 billion tons of carbon per year for a combination of land management strategies. A global strategy for reducing atmospheric carbon dioxide concentration will require the implementation of multiple options. The advantage of carbon storage in restored drylands is that it comes as a side benefit to programs that are also justifiable in terms of land management.

  15. Surface Heat Flux Corrections for Global Ocean Forecasts

    NASA Astrophysics Data System (ADS)

    Garraffo, Z. D.; Hogan, P. J.; Mehra, A.; Rivin, I.; Balasubramaniyan, B.; Spindler, T. D.; Kim, H. C.; Paturi, S.

    2016-02-01

    RTOFS (Real Time Ocean Forecast System) - Global is the first global eddy resolving ocean forecast system implemented operationally at NOAA/NWS/NCEP in close collaboration with US Navy. Recently upgraded version 1.1 (which was developed and validated at NRL) uses the Hybrid Coordinates Ocean Model (HYCOM) at 1/12 degree coupled with Los Alamos Community sea ICE model (CICE). The forecast system runs once a day and produces forecasts from the daily initialization fields produced at NAVOCEANO (NAVal OCEANographic Office) which use NCODA (Navy Coupled Ocean Data Assimilation), a 3DVAR data assimilation methodology (Cummings and Smedstad, 2013). After a two-day spin up with hourly NCEP's Global Data Assimilation System (GDAS) atmospheric fluxes with the ocean model in forecast mode, the daily forecast cycle is forced with 3-hourly momentum, radiation and precipitation fluxes from NCEP's Global Forecast System fields for the next eight days. Following flux-corrections efforts at NRL (Metzger et al. 2013, NRL report), heat flux corrections are computed for the RTOFS v1.1 configuration. To assess sensitivity to upgrades in GFS/GDAS and HYCOM, these radiative corrections are compared with forecasts produced with other versions of NCEP forcing. Impacts of flux corrections in SST errors will be discussed.

  16. Global ocean modeling on the Connection Machine

    SciTech Connect

    Smith, R.D.; Dukowicz, J.K.; Malone, R.C.

    1993-10-01

    The authors have developed a version of the Bryan-Cox-Semtner ocean model (Bryan, 1969; Semtner, 1976; Cox, 1984) for massively parallel computers. Such models are three-dimensional, Eulerian models that use latitude and longitude as the horizontal spherical coordinates and fixed depth levels as the vertical coordinate. The incompressible Navier-Stokes equations, with a turbulent eddy viscosity, and mass continuity equation are solved, subject to the hydrostatic and Boussinesq approximations. The traditional model formulation uses a rigid-lid approximation (vertical velocity = 0 at the ocean surface) to eliminate fast surface waves. These waves would otherwise require that a very short time step be used in numerical simulations, which would greatly increase the computational cost. To solve the equations with the rigid-lid assumption, the equations of motion are split into two parts: a set of twodimensional ``barotropic`` equations describing the vertically-averaged flow, and a set of three-dimensional ``baroclinic`` equations describing temperature, salinity and deviations of the horizontal velocities from the vertically-averaged flow.

  17. Global environmental change issues in the western Indian ocean region

    SciTech Connect

    Gable, F.J.; Aubrey, D.G.; Gentile, J.H.

    1991-01-01

    Global climate change caused by increased atmospheric trace gas loading is expected to cause a variety of direct and indirect impacts. These impacts include rising sea levels, changes in storm climates, changes in precipitation patterns, and alterations of ocean circulation patterns. The purpose of the paper is to place into a regional context for the Western Indian Ocean region the problems arising from changes in global climate. Specifically, the paper will focus on the potential for impacts in the coastal zone, where the indirect pressures of climate change and anthropogenic forcings (e.g. pollution, dredging, coral mining) and policy (land use, coastal zone) collide.

  18. The positive Indian Ocean Dipole-like response in the tropical Indian Ocean to global warming

    NASA Astrophysics Data System (ADS)

    Luo, Yiyong; Lu, Jian; Liu, Fukai; Wan, Xiuquan

    2016-04-01

    Climate models project a positive Indian Ocean Dipole (pIOD)-like SST response in the tropical Indian Ocean to global warming. By employing the Community Earth System Model and applying an overriding technique to its ocean component (version 2 of the Parallel Ocean Program), this study investigates the similarities and differences of the formation mechanisms for the changes in the tropical Indian Ocean during the pIOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, wind-thermocline-SST feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also found, including the fact that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the pIOD but by the anomalous upper-ocean stratification under global warming. These findings are further examined through an analysis of the mixed layer heat budget.

  19. The positive Indian Ocean Dipole-like response in the tropical Indian Ocean to global warming

    DOE PAGES

    Luo, Yiyong; Lu, Jian; Liu, Fukai; ...

    2016-02-04

    Climate models project a positive Indian Ocean Dipole (pIOD)-like SST response in the tropical Indian Ocean to global warming. By employing the Community Earth System Model (CESM) and applying an overriding technique to its ocean component Parallel Ocean Program version 2 (POP2), this study investigates the similarity and difference of the formation mechanisms for the changes in the tropical Indian Ocean during the pIOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, the Bjerknes feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases.more » Some differences are also found, including that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the pIOD while it is dominated by the anomalous upper-ocean stratification under global warming. Lastly, these findings above are further examined with an analysis of the mixed layer heat budget.« less

  20. The positive Indian Ocean Dipole-like response in the tropical Indian Ocean to global warming

    SciTech Connect

    Luo, Yiyong; Lu, Jian; Liu, Fukai; Wan, Xiuquan

    2016-02-04

    Climate models project a positive Indian Ocean Dipole (pIOD)-like SST response in the tropical Indian Ocean to global warming. By employing the Community Earth System Model (CESM) and applying an overriding technique to its ocean component Parallel Ocean Program version 2 (POP2), this study investigates the similarity and difference of the formation mechanisms for the changes in the tropical Indian Ocean during the pIOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, the Bjerknes feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also found, including that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the pIOD while it is dominated by the anomalous upper-ocean stratification under global warming. Lastly, these findings above are further examined with an analysis of the mixed layer heat budget.

  1. A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change

    NASA Astrophysics Data System (ADS)

    Abraham, J. P.; Baringer, M.; Bindoff, N. L.; Boyer, T.; Cheng, L. J.; Church, J. A.; Conroy, J. L.; Domingues, C. M.; Fasullo, J. T.; Gilson, J.; Goni, G.; Good, S. A.; Gorman, J. M.; Gouretski, V.; Ishii, M.; Johnson, G. C.; Kizu, S.; Lyman, J. M.; Macdonald, A. M.; Minkowycz, W. J.; Moffitt, S. E.; Palmer, M. D.; Piola, A. R.; Reseghetti, F.; Schuckmann, K.; Trenberth, K. E.; Velicogna, I.; Willis, J. K.

    2013-09-01

    evolution of ocean temperature measurement systems is presented with a focus on the development and accuracy of two critical devices in use today (expendable bathythermographs and conductivity-temperature-depth instruments used on Argo floats). A detailed discussion of the accuracy of these devices and a projection of the future of ocean temperature measurements are provided. The accuracy of ocean temperature measurements is discussed in detail in the context of ocean heat content, Earth's energy imbalance, and thermosteric sea level rise. Up-to-date estimates are provided for these three important quantities. The total energy imbalance at the top of atmosphere is best assessed by taking an inventory of changes in energy storage. The main storage is in the ocean, the latest values of which are presented. Furthermore, despite differences in measurement methods and analysis techniques, multiple studies show that there has been a multidecadal increase in the heat content of both the upper and deep ocean regions, which reflects the impact of anthropogenic warming. With respect to sea level rise, mutually reinforcing information from tide gauges and radar altimetry shows that presently, sea level is rising at approximately 3 mm yr-1 with contributions from both thermal expansion and mass accumulation from ice melt. The latest data for thermal expansion sea level rise are included here and analyzed.

  2. Space-based lidar measurements of global ocean carbon stocks

    NASA Astrophysics Data System (ADS)

    Behrenfeld, Michael J.; Hu, Yongxiang; Hostetler, Chris A.; Dall'Olmo, Giorgio; Rodier, Sharon D.; Hair, John W.; Trepte, Charles R.

    2013-08-01

    Global ocean phytoplankton biomass (Cphyto) and total particulate organic carbon (POC) stocks have largely been characterized from space using passive ocean color measurements. A space-based light detection and ranging (lidar) system can provide valuable complementary observations for Cphyto and POC assessments, with benefits including day-night sampling, observations through absorbing aerosols and thin cloud layers, and capabilities for vertical profiling through the water column. Here we use measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) to quantify global Cphyto and POC from retrievals of subsurface particulate backscatter coefficients (bbp). CALIOP bbp data compare favorably with airborne, ship-based, and passive ocean data and yield global average mixed-layer standing stocks of 0.44 Pg C for Cphyto and 1.9 Pg for POC. CALIOP-based Cphyto and POC data exhibit global distributions and seasonal variations consistent with ocean plankton ecology. Our findings support the use of spaceborne lidar measurements for advancing understanding of global plankton systems.

  3. A global ocean climatology of preindustrial and modern ocean δ13C

    NASA Astrophysics Data System (ADS)

    Eide, Marie; Olsen, Are; Ninnemann, Ulysses S.; Johannessen, Truls

    2017-03-01

    We present a global ocean climatology of dissolved inorganic carbon δ13C (‰) corrected for the 13C-Suess effect, preindustrial δ13C. This was constructed by first using Olsen and Ninnemann's (2010) back-calculation method on data from 25 World Ocean Circulation Experiment cruises to reconstruct the preindustrial δ13C on sections spanning all major oceans. Next, we developed five multilinear regression equations, one for each major ocean basin, which were applied on the World Ocean Atlas data to construct the climatology. This reveals the natural δ13C distribution in the global ocean. Compared to the modern distribution, the preindustrial δ13C spans a larger range of values. The maxima, of up to 1.8‰, occurs in the subtropical gyres of all basins, in the upper and intermediate waters of the North Atlantic, as well as in mode waters with a Southern Ocean origin. Particularly strong gradients occur at intermediate depths, revealing a strong potential for using δ13C as a tracer for changes in water mass geometry at these levels. Further, we identify a much tighter relationship between δ13C and apparent oxygen utilization (AOU) than between δ13C and phosphate. This arises because, in contrast to phosphate, AOU and δ13C are both partly reset when waters are ventilated in the Southern Ocean and underscore that δ13C is a highly robust proxy for past changes in ocean oxygen content and ocean ventilation. Our global preindustrial δ13C climatology is openly accessible and can be used, for example, for improved model evaluation and interpretation of sediment δ13C records.

  4. Global View of the Arctic Ocean

    NASA Image and Video Library

    2000-09-20

    NASA researchers have new [sic] insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts. Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites. http://photojournal.jpl.nasa.gov/catalog/PIA02970

  5. Vertical resolution of baroclinic modes in global ocean models

    NASA Astrophysics Data System (ADS)

    Stewart, K. D.; Hogg, A. McC.; Griffies, S. M.; Heerdegen, A. P.; Ward, M. L.; Spence, P.; England, M. H.

    2017-05-01

    Improvements in the horizontal resolution of global ocean models, motivated by the horizontal resolution requirements for specific flow features, has advanced modelling capabilities into the dynamical regime dominated by mesoscale variability. In contrast, the choice of the vertical grid remains a subjective choice, and it is not clear that efforts to improve vertical resolution adequately support their horizontal counterparts. Indeed, considering that the bulk of the vertical ocean dynamics (including convection) are parameterized, it is not immediately obvious what the vertical grid is supposed to resolve. Here, we propose that the primary purpose of the vertical grid in a hydrostatic ocean model is to resolve the vertical structure of horizontal flows, rather than to resolve vertical motion. With this principle we construct vertical grids based on their abilities to represent baroclinic modal structures commensurate with the theoretical capabilities of a given horizontal grid. This approach is designed to ensure that the vertical grids of global ocean models complement (and, importantly, to not undermine) the resolution capabilities of the horizontal grid. We find that for z-coordinate global ocean models, at least 50 well-positioned vertical levels are required to resolve the first baroclinic mode, with an additional 25 levels per subsequent mode. High-resolution ocean-sea ice simulations are used to illustrate some of the dynamical enhancements gained by improving the vertical resolution of a 1/10° global ocean model. These enhancements include substantial increases in the sea surface height variance (∼30% increase south of 40°S), the barotropic and baroclinic eddy kinetic energies (up to 200% increase on and surrounding the Antarctic continental shelf and slopes), and the overturning streamfunction in potential density space (near-tripling of the Antarctic Bottom Water cell at 65°S).

  6. Sources of global warming in upper ocean temperature during El Niño

    USGS Publications Warehouse

    White, Warren B.; Cayan, Daniel R.; Dettinger, Mike; Auad, Guillermo

    2001-01-01

    Global average sea surface temperature (SST) from 40°S to 60°N fluctuates ±0.3°C on interannual period scales, with global warming (cooling) during El Niño (La Niña). About 90% of the global warming during El Niño occurs in the tropical global ocean from 20°S to 20°N, half because of large SST anomalies in the tropical Pacific associated with El Niño and the other half because of warm SST anomalies occurring over ∼80% of the tropical global ocean. From examination of National Centers for Environmental Prediction [Kalnay et al., 1996] and Comprehensive Ocean-Atmosphere Data Set [Woodruff et al., 1993] reanalyses, tropical global warming during El Niño is associated with higher troposphere moisture content and cloud cover, with reduced trade wind intensity occurring during the onset phase of El Niño. During this onset phase the tropical global average diabatic heat storage tendency in the layer above the main pycnocline is 1–3 W m−2above normal. Its principal source is a reduction in the poleward Ekman heat flux out of the tropical ocean of 2–5 W m−2. Subsequently, peak tropical global warming during El Niño is dissipated by an increase in the flux of latent heat to the troposphere of 2–5 W m−2, with reduced shortwave and longwave radiative fluxes in response to increased cloud cover tending to cancel each other. In the extratropical global ocean the reduction in poleward Ekman heat flux out of the tropics during the onset of El Niño tends to be balanced by reduction in the flux of latent heat to the troposphere. Thus global warming and cooling during Earth's internal mode of interannual climate variability arise from fluctuations in the global hydrological balance, not the global radiation balance. Since it occurs in the absence of extraterrestrial and anthropogenic forcing, global warming on decadal, interdecadal, and centennial period scales may also occur in association with Earth's internal modes of climate variability on those scales.

  7. Seafloor 2030 - Building a Global Ocean Map through International Collaboration

    NASA Astrophysics Data System (ADS)

    Ferrini, V. L.; Wigley, R. A.; Falconer, R. K. H.; Jakobsson, M.; Allen, G.; Mayer, L. A.; Schmitt, T.; Rovere, M.; Weatherall, P.; Marks, K. M.

    2016-12-01

    With more than 85% of the ocean floor unmapped, a huge proportion of our planet remains unexplored. Creating a comprehensive map of seafloor bathymetry remains a true global challenge that can only be accomplished through collaboration and partnership between governments, industry, academia, research organizations and non-government organizations. The objective of Seafloor 2030 is to comprehensively map the global ocean floor to resolutions that enable exploration and improved understanding of ocean processes, while informing maritime policy and supporting the management of natural marine resources for a sustainable Blue Economy. Seafloor 2030 is the outcome of the Forum for Future of Ocean Floor Mapping held in Monaco in June 2016, which was held under the auspices of GEBCO and the Nippon Foundation of Japan. GEBCO is the only international organization mandated to map the global ocean floor and is guided by the International Hydrographic Organization (IHO) and the Intergovernmental Oceanographic Commission of UNESCO. The task of completely mapping the ocean floor will require new global coordination to ensure that both existing data are identified and that new mapping efforts are coordinated to help efficiently "map the gaps." Fundamental to achieving Seafloor 2030 will be greater access to data, tools and technology, particularly for developing and coastal nations. This includes bathymetric post-processing and analysis software, database technology, computing infrastructure and gridding techniques as well as the latest developments in seafloor mapping methods and emerging crowd-sourced bathymetry initiatives. The key to achieving this global bathymetric map is capacity building and education - including greater coordination between scientific research and industry and the effective engagement of international organizations such as the United Nations.

  8. Decadal Changes in Global Ocean Annual Primary Production

    NASA Technical Reports Server (NTRS)

    Gregg, Watson; Conkright, Margarita E.; Behrenfeld, Michael J.; Ginoux, Paul; Casey, Nancy W.; Koblinsky, Chester J. (Technical Monitor)

    2002-01-01

    The Sea-viewing Wide Field-of-View Sensor (SeaWiFS) has produced the first multi-year time series of global ocean chlorophyll observations since the demise of the Coastal Zone Color Scanner (CZCS) in 1986. Global observations from 1997-present from SeaWiFS combined with observations from 1979-1986 from the CZCS should in principle provide an opportunity to observe decadal changes in global ocean annual primary production, since chlorophyll is the primary driver for estimates of primary production. However, incompatibilities between algorithms have so far precluded quantitative analysis. We have developed and applied compatible processing methods for the CZCS, using modern advances in atmospheric correction and consistent bio-optical algorithms to advance the CZCS archive to comparable quality with SeaWiFS. We applied blending methodologies, where in situ data observations are incorporated into the CZCS and SeaWiFS data records, to provide improvement of the residuals. These re-analyzed, blended data records provide maximum compatibility and permit, for the first time, a quantitative analysis of the changes in global ocean primary production in the early-to-mid 1980's and the present, using synoptic satellite observations. An intercomparison of the global and regional primary production from these blended satellite observations is important to understand global climate change and the effects on ocean biota. Photosynthesis by chlorophyll-containing phytoplankton is responsible for biotic uptake of carbon in the oceans and potentially ultimately from the atmosphere. Global ocean annual primary decreased from the CZCS record to SeaWiFS, by nearly 6% from the early 1980s to the present. Annual primary production in the high latitudes was responsible for most of the decadal change. Conversely, primary production in the low latitudes generally increased, with the exception of the tropical Pacific. The differences and similarities of the two data records provide evidence

  9. Perfluoroalkylated substances in the global tropical and subtropical surface oceans.

    PubMed

    González-Gaya, Belén; Dachs, Jordi; Roscales, Jose L; Caballero, Gemma; Jiménez, Begoña

    2014-11-18

    In this study, perfluoroalkylated substances (PFASs) were analyzed in 92 surface seawater samples taken during the Malaspina 2010 expedition which covered all the tropical and subtropical Atlantic, Pacific and Indian oceans. Nine ionic PFASs including C6-C10 perfluoroalkyl carboxylic acids (PFCAs), C4 and C6-C8 perfluoroalkyl sulfonic acids (PFSAs) and two neutral precursors perfluoroalkyl sulfonamides (PFASAs), were identified and quantified. The Atlantic Ocean presented the broader range in concentrations of total PFASs (131-10900 pg/L, median 645 pg/L, n = 45) compared to the other oceanic basins, probably due to a better spatial coverage. Total concentrations in the Pacific ranged from 344 to 2500 pg/L (median = 527 pg/L, n = 27) and in the Indian Ocean from 176 to 1976 pg/L (median = 329, n = 18). Perfluorooctanesulfonic acid (PFOS) was the most abundant compound, accounting for 33% of the total PFASs globally, followed by perfluorodecanoic acid (PFDA, 22%) and perfluorohexanoic acid (PFHxA, 12%), being the rest of the individual congeners under 10% of total PFASs, even for perfluorooctane carboxylic acid (PFOA, 6%). PFASAs accounted for less than 1% of the total PFASs concentration. This study reports the ubiquitous occurrence of PFCAs, PFSAs, and PFASAs in the global ocean, being the first attempt, to our knowledge, to show a comprehensive assessment in surface water samples collected in a single oceanic expedition covering tropical and subtropical oceans. The potential factors affecting their distribution patterns were assessed including the distance to coastal regions, oceanic subtropical gyres, currents and biogeochemical processes. Field evidence of biogeochemical controls on the occurrence of PFASs was tentatively assessed considering environmental variables (solar radiation, temperature, chlorophyll a concentrations among others), and these showed significant correlations with some PFASs, but explaining small to moderate percentages of variability

  10. Global Ocean Sedimentation Patterns: Plate Tectonic History Versus Climate Change

    NASA Astrophysics Data System (ADS)

    Goswami, A.; Reynolds, E.; Olson, P.; Hinnov, L. A.; Gnanadesikan, A.

    2014-12-01

    Global sediment data (Whittaker et al., 2013) and carbonate content data (Archer, 1996) allows examination of ocean sedimentation evolution with respect to age of the underlying ocean crust (Müller et al., 2008). From these data, we construct time series of ocean sediment thickness and carbonate deposition rate for the Atlantic, Pacific, and Indian ocean basins for the past 120 Ma. These time series are unique to each basin and reflect an integrated response to plate tectonics and climate change. The goal is to parameterize ocean 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 ocean sedimentation from 0 to 120 Ma. In the North and South Atlantic and Indian oceans, 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 oceans 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 climate change. Unlike total sediment thickness, carbonate deposition rates decrease smoothly with crustal age in all basins, with the primary controls being ocean 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

  11. Potential increasing dominance of heterotrophy in the global ocean

    NASA Astrophysics Data System (ADS)

    Kvale, K. F.; Meissner, K. J.; Keller, D. P.

    2015-07-01

    Autotrophy is largely resource-limited in the modern ocean. Paleo evidence indicates this was not necessarily the case in warmer climates, and modern observations as well as standard metabolic theory suggest continued ocean warming could shift global ecology towards heterotrophy, thereby reducing autotrophic nutrient limitation. Such a shift would entail strong nutrient recycling in the upper ocean and high rates of net primary production (NPP), yet low carbon export to the deep ocean and sediments. We demonstrate transition towards such a state in the early 22nd century as a response to business-as-usual representative concentration pathway forcing (RCP8.5) in an intermediate complexity Earth system model in three configurations; with and without an explicit calcifier phytoplankton class and calcite ballast model. In all models nutrient regeneration in the near-surface becomes an increasingly important driver of primary production. The near-linear relationship between changes in NPP and global sea surface temperature (SST) found over the 21st century becomes exponential above a 2-4{ }\\circ {{C}} global mean SST change. This transition to a more heterotrophic ocean agrees roughly with metabolic theory.

  12. Global ocean conveyor lowers extinction risk in the deep sea

    USGS Publications Warehouse

    Henry, Lea-Anne; Frank, Norbert; Hebbeln, Dierk; Weinberg, Claudia; Robinson, Laura; van de Flierdt, Tina; Dahl, Mikael; Douarin, Melanie; Morrison, Cheryl; Correa, Matthias Lopez; Rogers, Alex D.; Ruckelshausen, Mario; Roberts, J. Murray

    2014-01-01

    General paradigms of species extinction risk are urgently needed as global habitat loss and rapid climate change threaten Earth with what could be its sixth mass extinction. Using the stony coral Lophelia pertusa as a model organism with the potential for wide larval dispersal, we investigated how the global ocean conveyor drove an unprecedented post-glacial range expansion in Earth׳s largest biome, the deep sea. We compiled a unique ocean-scale dataset of published radiocarbon and uranium-series dates of fossil corals, the sedimentary protactinium–thorium record of Atlantic meridional overturning circulation (AMOC) strength, authigenic neodymium and lead isotopic ratios of circulation pathways, and coral biogeography, and integrated new Bayesian estimates of historic gene flow. Our compilation shows how the export of Southern Ocean and Mediterranean waters after the Younger Dryas 11.6 kyr ago simultaneously triggered two dispersal events in the western and eastern Atlantic respectively. Each pathway injected larvae from refugia into ocean currents powered by a re-invigorated AMOC that led to the fastest postglacial range expansion ever recorded, covering 7500 km in under 400 years. In addition to its role in modulating global climate, our study illuminates how the ocean conveyor creates broad geographic ranges that lower extinction risk in the deep sea.

  13. Global ocean conveyor lowers extinction risk in the deep sea

    NASA Astrophysics Data System (ADS)

    Henry, Lea-Anne; Frank, Norbert; Hebbeln, Dierk; Wienberg, Claudia; Robinson, Laura; van de Flierdt, Tina; Dahl, Mikael; Douarin, Mélanie; Morrison, Cheryl L.; López Correa, Matthias; Rogers, Alex D.; Ruckelshausen, Mario; Roberts, J. Murray

    2014-06-01

    General paradigms of species extinction risk are urgently needed as global habitat loss and rapid climate change threaten Earth with what could be its sixth mass extinction. Using the stony coral Lophelia pertusa as a model organism with the potential for wide larval dispersal, we investigated how the global ocean conveyor drove an unprecedented post-glacial range expansion in Earth's largest biome, the deep sea. We compiled a unique ocean-scale dataset of published radiocarbon and uranium-series dates of fossil corals, the sedimentary protactinium-thorium record of Atlantic meridional overturning circulation (AMOC) strength, authigenic neodymium and lead isotopic ratios of circulation pathways, and coral biogeography, and integrated new Bayesian estimates of historic gene flow. Our compilation shows how the export of Southern Ocean and Mediterranean waters after the Younger Dryas 11.6 kyr ago simultaneously triggered two dispersal events in the western and eastern Atlantic respectively. Each pathway injected larvae from refugia into ocean currents powered by a re-invigorated AMOC that led to the fastest postglacial range expansion ever recorded, covering 7500 km in under 400 years. In addition to its role in modulating global climate, our study illuminates how the ocean conveyor creates broad geographic ranges that lower extinction risk in the deep sea.

  14. Role of ocean ventilation in setting regional patterns of uptake and storage of anthropogenic CO2: insights from inverse estimates of the ocean's transport Green function

    NASA Astrophysics Data System (ADS)

    Khatiwala, S.; Primeau, F. W.; Holzer, M. B.

    2010-12-01

    Atmospheric CO2 levels have steadily increased over the past 200 years, from around 280 ppm at the start of the industrial period, to presently around 390 ppm. This increase, due to the burning of fossil fuels by human activity, has been implicated as the predominant cause of global climate change. The ocean plays a crucial role in mitigating the effects of this perturbation to the climate system, globally sequestering around a third of anthropogenic carbon (Cant) emissions. However, there are significant spatial variations in CO2 uptake, leading to debate about the relative roles of the high and low latitude oceans in absorbing CO2. Here, we apply observationally-based estimates of the Cant distribution and ocean ventilation parameters to gain insight into the mechanisms controlling the regional patterns of uptake and storage. We find that the high latitude oceans, conventionally regarded as the principal conduits by which Cant is taken up by the ocean, in fact take up substantially less Cant than expected from their volumetric contribution. In particular, the North Atlantic and Southern Ocean (south of 50 S) volumetrically make up 65% of the global ocean, but account for only ~30% of the global Cant uptake. In contrast, the tropics contribute only 4.5% to the water mass, but are responsible for 30% of the anthropogenic CO2 uptake. To understand these results, we analyze the ocean's ventilation-rate distribution or Green function (G), which we estimate using inverse methods. We show that the temporal structure of G is crucial for determining which surface regions have contributed most to the ocean's Cant uptake and for distinguishing their contributions to the Cant inventory from their volumetric contributions. Our results indicate that Cant uptake is not related in a simple manner to the aggregate amount of deep water formed in a particular region, but is sensitive to the shape of the ventilation-rate distribution. Specifically, our analysis of the temporal

  15. An operational global ocean forecast system and its applications

    NASA Astrophysics Data System (ADS)

    Mehra, A.; Tolman, H. L.; Rivin, I.; Rajan, B.; Spindler, T.; Garraffo, Z. D.; Kim, H.

    2012-12-01

    A global Real-Time Ocean Forecast System (RTOFS) was implemented in operations at NCEP/NWS/NOAA on 10/25/2011. This system is based on an eddy resolving 1/12 degree global HYCOM (HYbrid Coordinates Ocean Model) and is part of a larger national backbone capability of ocean modeling at NWS in strong partnership with US Navy. The forecast system is run once a day and produces a 6 day long forecast using the daily initialization fields produced at NAVOCEANO using NCODA (Navy Coupled Ocean Data Assimilation), a 3D multi-variate data assimilation methodology. As configured within RTOFS, HYCOM has a horizontal equatorial resolution of 0.08 degrees or ~9 km. The HYCOM grid is on a Mercator projection from 78.64 S to 47 N and north of this it employs an Arctic dipole patch where the poles are shifted over land to avoid a singularity at the North Pole. This gives a mid-latitude (polar) horizontal resolution of approximately 7 km (3.5 km). The coastline is fixed at 10 m isobath with open Bering Straits. This version employs 32 hybrid vertical coordinate surfaces with potential density referenced to 2000 m. Vertical coordinates can be isopycnals, often best for resolving deep water masses, levels of equal pressure (fixed depths), best for the well mixed unstratified upper ocean and sigma-levels (terrain-following), often the best choice in shallow water. The dynamic ocean model is coupled to a thermodynamic energy loan ice model and uses a non-slab mixed layer formulation. The forecast system is forced with 3-hourly momentum, radiation and precipitation fluxes from the operational Global Forecast System (GFS) fields. Results include global sea surface height and three dimensional fields of temperature, salinity, density and velocity fields used for validation and evaluation against available observations. Several downstream applications of this forecast system will also be discussed which include search and rescue operations at US Coast Guard, navigation safety information

  16. Satellite-detected fluorescence reveals global physiology of ocean phytoplankton

    NASA Astrophysics Data System (ADS)

    Behrenfeld, M. J.; Westberry, T. K.; Boss, E. S.; O'Malley, R. T.; Siegel, D. A.; Wiggert, J. D.; Franz, B. A.; McClain, C. R.; Feldman, G. C.; Doney, S. C.; Moore, J. K.; Dall'Olmo, G.; Milligan, A. J.; Lima, I.; Mahowald, N.

    2009-05-01

    Phytoplankton photosynthesis links global ocean biology and climate-driven fluctuations in the physical environment. These interactions are largely expressed through changes in phytoplankton physiology, but physiological status has proven extremely challenging to characterize globally. Phytoplankton fluorescence does provide a rich source of physiological information long exploited in laboratory and field studies, and is now observed from space. Here we evaluate the physiological underpinnings of global variations in satellite-based phytoplankton chlorophyll fluorescence. The three dominant factors influencing fluorescence distributions are chlorophyll concentration, pigment packaging effects on light absorption, and light-dependent energy-quenching processes. After accounting for these three factors, resultant global distributions of quenching-corrected fluorescence quantum yields reveal a striking consistency with anticipated patterns of iron availability. High fluorescence quantum yields are typically found in low iron waters, while low quantum yields dominate regions where other environmental factors are most limiting to phytoplankton growth. Specific properties of photosynthetic membranes are discussed that provide a mechanistic view linking iron stress to satellite-detected fluorescence. Our results present satellite-based fluorescence as a valuable tool for evaluating nutrient stress predictions in ocean ecosystem models and give the first synoptic observational evidence that iron plays an important role in seasonal phytoplankton dynamics of the Indian Ocean. Satellite fluorescence may also provide a path for monitoring climate-phytoplankton physiology interactions and improving descriptions of phytoplankton light use efficiencies in ocean productivity models.

  17. NOAA's Role in Sustaining Global Ocean Observations: Future Plans for OAR's Ocean Observing and Monitoring Division

    NASA Astrophysics Data System (ADS)

    Todd, James; Legler, David; Piotrowicz, Stephen; Raymond, Megan; Smith, Emily; Tedesco, Kathy; Thurston, Sidney

    2017-04-01

    The Ocean Observing and Monitoring Division (OOMD, formerly the Climate Observation Division) of the National Oceanic and Atmospheric Administration (NOAA) Climate Program Office provides long-term, high-quality global observations, climate information and products for researchers, forecasters, assessments and other users of environmental information. In this context, OOMD-supported activities serve a foundational role in an enterprise that aims to advance 1) scientific understanding, 2) monitoring and prediction of climate and 3) understanding of potential impacts to enable a climate resilient society. Leveraging approximately 50% of the Global Ocean Observing System, OOMD employs an internationally-coordinated, multi-institution global strategy that brings together data from multiple platforms including surface drifting buoys, Argo profiling floats, flux/transport moorings (RAMA, PIRATA, OceanSITES), GLOSS tide gauges, SOOP-XBT and SOOP-CO2, ocean gliders and repeat hydrographic sections (GO-SHIP). OOMD also engages in outreach, education and capacity development activities to deliver training on the social-economic applications of ocean data. This presentation will highlight recent activities and plans for 2017 and beyond.

  18. Cloud and ocean effects on global greenhouse warming

    SciTech Connect

    Hoffert, M.I.

    1991-02-01

    Six months into the above-referenced grant, we are making good progress on our research plan. We intend to develop a new generation of transient climate/ocean model capable of reflecting feedbacks associated with clouds and ocean dynamics, and to use them to better constrain the transient climate response to increased greenhouse gas concentrations in the atmosphere. This is a necessary step in quantifying the links between radiative forcing of the atmosphere and climate response on 10--100 year time scales. The modelling work involves, on the one hand, developing a better characterization of cloud forcing and feedback, and on the other, a new generation of ocean/climate model incorporating feedbacks from the changing stratification of the ocean as heat is absorbed during periods of global warming. 3 figs.

  19. Tsunami speed variations in density-stratified compressible global oceans

    NASA Astrophysics Data System (ADS)

    Watada, Shingo

    2013-08-01

    Tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth-variable sound speeds and density gradients. For a 4 km deep ocean, the total tsunami speed reduction is 0.44% compared with incompressible homogeneous seawater; two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression. Tsunami speeds are computed for global ocean density and sound speed profiles, and characteristic structures are discussed. Tsunami speed reductions are proportional to ocean depth with small variations, except in warm Mediterranean seas. The impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of transoceanic tsunamis.

  20. Intraseasonal oscillation in global ocean temperature inferred from Argo

    NASA Astrophysics Data System (ADS)

    Hu, Ruijin; Wei, Meng

    2013-01-01

    The intraseasonal oscillation (ISO; 14-97-day periods) of temperature in the upper 2000 m of the global ocean was studied based on Argo observations from 2003-2008. It is shown that near the surface the ISO existed mainly in a band east of 60°E, between 10°S and 10°N, and the region around the Antarctic Circumpolar Current (ACC). At other levels analyzed, the ISOs also existed in the regions of the Kuroshio, the Gulf Stream, the Indonesian throughflow, the Somalia current, and the subtropical countercurrent (STCC) of the North Pacific. The intraseasonal signals can be seen even at depths of about 2000 m in some regions of the global ocean. The largest amplitude of ISO appeared at the thermocline of the equatorial Pacific, Atlantic and Indian Ocean, with maximum standard deviation (STD) exceeding 1.2°C. The ACC, the Kuroshio, and the Gulf Stream regions all exhibited large STD for all levels analyzed. Especially at 1000 m, the largest STD appeared in the south and southeast of South Africa-a part of the ACC, with a maximum value that reached 0.5°C. The ratios of the intraseasonal temperature variance to the total variance at 1000 m and at the equator indicated that, in a considerable part of the global deep ocean, the ISO was dominant in the variations of temperature, since such a ratio exceeded even 50% there. A case study also confirmed the existence of the ISO in the deep ocean. These results provide useful information for the design of field observations in the global ocean. Analysis and discussion are also given for the mechanism of the ISO.

  1. Evaluating the deep-ocean circulation of a global ocean model using carbon isotopic ratios

    NASA Astrophysics Data System (ADS)

    Paul, André; Dutkiewicz, Stephanie; Gebbie, Jake; Losch, Martin; Marchal, Olivier

    2016-04-01

    We study the sensitivity of a global three-dimensional biotic ocean carbon-cycle model to the parameterizations of gas exchange and biological productivity as well as to deep-ocean circulation strength, and we employ the carbon isotopic ratios δ13C and Δ14C of dissolved inorganic carbon for a systematic evaluation against observations. Radiocarbon (Δ14C) in particular offers the means to assess the model skill on a time scale of 100 to 1000 years relevant to the deep-ocean circulation. The carbon isotope ratios are included as tracers in the MIT general circulation model (MITgcm). The implementation involves the fractionation processes during photosynthesis and air-sea gas exchange. We present the results of sixteen simulations combining two different parameterizations of the piston velocity, two different parameterizations of biological productivity (including the effect of iron fertilization) and four different overturning rates. These simulations were first spun up to equilibrium (more than 10,000 years of model simulation) and then continued from AD 1765 to AD 2002. For the model evaluation, we followed the OCMIP-2 (Ocean Carbon-Cycle Model Intercomparision Project phase two) protocol, comparing the results to GEOSECS (Geochemical Ocean Sections Survey) and WOCE (World Ocean Circulation Experiment) δ13C and natural Δ14C data in the world ocean. The range of deep natural Δ14C (below 1000 m) for our single model (MITgcm) was smaller than for the group of different OCMIP-2 models. Furthermore, differences between different model parameterizations were smaller than for different overturning rates. We conclude that carbon isotope ratios are a useful tool to evaluate the deep-ocean circulation. Since they are also available from deep-sea sediment records, we postulate that the simulation of carbon isotope ratios in a global ocean model will aid in estimating the deep-ocean circulation and climate during present and past.

  2. The global oxidation state of the upper oceanic crust

    NASA Astrophysics Data System (ADS)

    Rutter, J.; Harris, M.; Coggon, R. M.; Alt, J.; Smith-Duque, C. E.; Teagle, D. A.

    2012-12-01

    The oxidation state of the oceanic crust is an important component of the Earth system. The widespread oxidation of the crust is a major contributor to the redox state of the mantle due to the subduction of hydrothermally altered oceanic crust, which supplies 10 - 25 % of the net ferric iron flux to the global mantle Fe3+/FeTOT budget (Lécuyer and Ricard, 1999). Secondly, the degree of oxidation of the upper oceanic crust provides a measure of the biomass of microbial life sub-basement (Bach and Edwards, 2003). Thirdly, oxidation state analyses of oceanic basalt give information on the environment and relative timings of local hydrothermal alteration events. To date comprehensive measurements of Fe3+/FeTOT for the oceanic crust are lacking. Post crystallisation oxidation processes, occurring predominantly in the upper basaltic layers of the crust, elevate ratios of ferric to total iron (Fe3+/FeTOT) from mantle levels of 0.16 ± 0.01 (Cottrell and Kelley, 2011). Ferrous (Fe2+/) iron is oxidised to ferric (Fe3+/) iron during reaction with oxidised seawater, which circulates through oceanic crust for tens of millions of years following crustal formation. This study integrates published data with new analyses from six ocean crustal boreholes to categorise the global oxidation state of the upper crust. Samples range from <1 to 129 Ma, and represent basalt from medium to superfast spreading centres, depths between <100 - 2000 mbsf, and at a variety of sedimentary cover rates and thicknesses. Results show that by 1 Ma, the Fe3+/FeTOT ratio of the bulk crust is already raised to an average of 0.28 ± 0.07, implying that the oxidation state is established very early in the lifetime of the ocean crust. Post 1 Ma, Fe3+/FeTOT ratios are more variable, reflecting the effects of prolonged exposure to circulating seawater, but are on average ~0.35.

  3. Patterns and Emerging Trends in Global Ocean Health

    PubMed Central

    Halpern, Benjamin S.; Longo, Catherine; Lowndes, Julia S. Stewart; Best, Benjamin D.; Frazier, Melanie; Katona, Steven K.; Kleisner, Kristin M.; Rosenberg, Andrew A.; Scarborough, Courtney; Selig, Elizabeth R.

    2015-01-01

    International and regional policies aimed at managing ocean ecosystem health need quantitative and comprehensive indices to synthesize information from a variety of sources, consistently measure progress, and communicate with key constituencies and the public. Here we present the second annual global assessment of the Ocean Health Index, reporting current scores and annual changes since 2012, recalculated using updated methods and data based on the best available science, for 221 coastal countries and territories. The Index measures performance of ten societal goals for healthy oceans on a quantitative scale of increasing health from 0 to 100, and combines these scores into a single Index score, for each country and globally. The global Index score improved one point (from 67 to 68), while many country-level Index and goal scores had larger changes. Per-country Index scores ranged from 41–95 and, on average, improved by 0.06 points (range -8 to +12). Globally, average scores increased for individual goals by as much as 6.5 points (coastal economies) and decreased by as much as 1.2 points (natural products). Annual updates of the Index, even when not all input data have been updated, provide valuable information to scientists, policy makers, and resource managers because patterns and trends can emerge from the data that have been updated. Changes of even a few points indicate potential successes (when scores increase) that merit recognition, or concerns (when scores decrease) that may require mitigative action, with changes of more than 10–20 points representing large shifts that deserve greater attention. Goal scores showed remarkably little covariance across regions, indicating low redundancy in the Index, such that each goal delivers information about a different facet of ocean health. Together these scores provide a snapshot of global ocean health and suggest where countries have made progress and where a need for further improvement exists. PMID:25774678

  4. Integrated studies of uncultured microbes in the global ocean (Invited)

    NASA Astrophysics Data System (ADS)

    Dupont, C.; Rusch, D.; Martiny, A.; Lasken, R.

    2010-12-01

    The Global Ocean Sampling (GOS) initiative at the J. Craig Venter Institute represents the most extensive metagenomic study of a single environment. Early findings highlighted the potential of shotgun metagenomics to expand our knowledge of marine microbial biodiversity and physiology. However, it also became clear that many of the abundant marine microbes remain uncultured, hindering a direct connection between phylogeny and ecophysiology. In two recent studies, a combination of single cell genomics and aggressive assembly of binned metagenomic data have resulted in the acquisition of multiple genomes for two uncultured but globally relevant organisms. Metabolic reconstructions of the whole genomes revealed unique physiological adaptations in marine Prochlorococcus to high nutrient, low Fe regions of the global ocean and illuminated the potential ecological role of the gamma-proteobacterial 16S clade SAR86. The internal reference genomes also facilitate fragment recruitment based biogeographical studies, both at the whole genome level and the protein level.

  5. Impacts of data assimilation on the global ocean carbonate system

    NASA Astrophysics Data System (ADS)

    Visinelli, L.; Masina, S.; Vichi, M.; Storto, A.; Lovato, T.

    2016-06-01

    In an ocean reanalysis, historical observations are combined with ocean and biogeochemical general circulation models to produce a reconstruction of the oceanic properties in past decades. This is one possible method to better constrain the role of the ocean carbon cycle in the determination of the air-sea CO2 flux. In this work, we investigate how the assimilation of physical variables and subsequently the combined assimilation of physical data and inorganic carbon variables - namely dissolved inorganic carbon (DIC) and alkalinity - affect the modelling of the marine carbonate system and the related air-sea CO2 fluxes. The performance of the two assimilation exercises are quantitatively assessed against the assimilated DIC and alkalinity data and the independent ocean surface pCO2 observations from global datasets. We obtain that the assimilation of physical observations has contrasting effects in different ocean basins when compared with the DIC and alkalinity data: it reduces the root-mean square error against the observed pCO2 in the Atlantic and Southern oceans, while increases the model error in the North Pacific and Indian Oceans. In both cases the corrected evaporation rates are the major factor determining the changes in concentrations. The assimilation of inorganic carbon variables on top of the physical data gives a generalized improvement in the model error of inorganic carbon variables, also improving the annual mean and spatial distribution of air-sea fluxes in agreement with other published estimates. These results indicate that data assimilation of physical and inorganic carbon data does not guarantee the improvement of the simulated pCO2 in all the oceanic regions; nevertheless, errors in pCO2 are reduced by a factor corresponding to those associated with the air-sea flux formulations.

  6. The Mercator-Ocean Forecasting Service: a 4D vision of the Global Ocean, Serving the Ocean Services

    NASA Astrophysics Data System (ADS)

    Toumazou, V.; Baudel, S.; Vinay, G.; Nouel, L.

    2005-12-01

    Mercator-Ocean is a public interest grouping formed in Toulouse in early 2002 by six major players in the French oceanography community: the space agency CNES, the scientific research centre CNRS, IFREMER (the institute of marine research and exploration), the development research institute IRD, the Meteo-France weather service, and SHOM (the French Navy's hydrography & oceanography department). In 1995, these same organizations gave themselves seven years to achieve a challenging objective: to conceive, develop and implement France's first operational oceanography system. The unique system would be capable of describing, analysing and predicting conditions at the ocean surface and subsurface in real time, anytime, anywhere in the world, even in the most inhospitable seas. That objective was met on 17 January 2001 with the release of the first Mercator ocean bulletin, providing a two-week forecast for the entire North Atlantic. Two thousands new forecast charts are now added to the MERCATOR bulletin every week. Building on these successes, a dedicated operational oceanography team, Mercator Ocean, was set up in 2002. Mercator-Ocean's mission is to deliver incremental improvements in the service provided by this new operational oceanography capability by increasing the resolution and the geographic coverage of the models used. The current high-resolution model offers a 6 km grid resolution, and the first models offering global ocean coverage has been implemented early 2004. A 1/4(°) model will be operated by the end of 2006. Objective 1- Develop an operational oceanography system using three-dimensional simulation and a high-resolution primitive-equation model capable of assimilating satellite data (from the Jason altimetry satellite in particular) and in-situ ocean observation data (particularly those gathered by the CORIOLIS centre). 2- Support applications for commercial shipping and naval forces, promote sustainable stewardship of the world's oceans

  7. Mercator-Ocean monitoring and forecasting : a 4D vision of the global ocean

    NASA Astrophysics Data System (ADS)

    Bahurel, P.; Toumazou, V.

    Mercator Ocean is a public interest grouping formed in Toulouse in early 2002 by six major players in the French oceanography community: the space agency CNES, the scientific research centre CNRS, IFREMER (the institute of marine research and exploration), the development research institute IRD, the Météo France weather service, and SHOM (the French Navy's hydrography & oceanography department). In 1995, these same organizations gave themselves seven years to achieve a challenging objective: to conceive, develop and implement France's first operational oceanography system. The unique system would be capable of describing, analysing and predicting conditions at the ocean surface and subsurface in real time, anytime, anywhere in the world, even in the most inhospitable seas. That objective was met on 17 January 2001 with the release of the first Mercator ocean bulletin, providing a two-week forecast for the entire North Atlantic. Two thousands new forecast charts are now added to the MERCATOR bulletin every week. Building on these successes, a dedicated operational oceanography team, Mercator Ocean, was set up in 2002. Mercator Ocean's mission is to deliver incremental improvements in the service provided by this new operational oceanography capability by increasing the resolution and the geographic coverage of the models used. The new high-resolution model that is now on line offers 6 km grid resolution, and the first models offering global ocean coverage will be implemented in 2004. Over the next four years, Mercator Ocean also plans to establish a European Operational Oceanography Centre in Toulouse. Objective 1. Develop an operational oceanography system using three-dimensional simulation and a high-resolution primitive-equation model capable of assimilating satellite data (from the Jason altimetry satellite in particular) and in-situ ocean observation data (particularly those gathered by the CORIOLIS centre). 2. Support applications for commercial shipping and

  8. (The ocean's role in the global carbon cycle)

    SciTech Connect

    Joos, L.F.

    1990-12-20

    The traveler collaborated with Dr. J. L. Sarmiento of the Program in Atmospheric Sciences, Princeton University, and Dr. U. Siegenthaler of the University of Bern in box-model studies of the potential enhancement of oceanic CO{sub 2} uptake by fertilizing the southern ocean with iron. As a result of this collaboration, a letter describing the results was submitted to the journal Nature. Sensitivity studies were carried out to gain a better understanding of the processes involved for a hypothetical iron fertilization of the ocean. An article that describes this work has been submitted to the journal Global Biogeochemical Cycles. The traveler and U. Siegenthaler are preparing a journal article describing a box model of the global carbon cycle that is an extension of the one-dimensional box-diffusion model. The traveler attended Oceanography 590b at the University of Washington in Friday Harbor. While at Friday Harbor, he started to collaborate with Drs. M. Warner, R. Gammon, and J. Bullister, all from the University of Washington, Seattle, to calibrate the global carbon cycle model with chlorofluorocarbon (CFC)-11 and CFC-12. The traveler started collaboration with Drs. J. C. Orr and J. L. Sarmiento to calculate apparent eddy diffusivities from the Princeton three-dimensional ocean model. The work is conducted by the University of Bern, Switzerland (the traveler is principal investigator), for a US Department of Energy program managed by Oak Ridge National Laboratory.

  9. Potential Increasing Dominance of Heterotrophy in the Global Ocean

    NASA Astrophysics Data System (ADS)

    Kvale, K.; Meissner, K. J.; Keller, D. P.

    2016-02-01

    Autotrophs are largely limited by resources in the modern ocean. However, standard metabolic theory suggests continued ocean warming could globally benefit heterotrophs, thereby reducing autotrophic nutrient limitation. The paleo record as well as modern observations offer evidence this has happened in the past and could happen again. Increasing dominance of heterotrophs would result in strong nutrient recycling in the upper ocean and high rates of net primary production (NPP), yet low carbon export to the deep ocean and sediments. We describe the transition towards such a state in the early 22nd century as a response to business-as-usual Representative Concentration Pathway forcing (RCP8.5) in an intermediate complexity Earth system model in three configurations: with and without an explicit calcifier phytoplankton class and calcite ballast model. In all models nutrient regeneration in the near surface becomes an increasingly important driver of primary production. The near-linear relationship between changes in NPP and global sea surface temperature (SST) found over the 21st century becomes exponential above a 2-4 °C global mean SST change. This transition to a more heterotrophic ocean agrees roughly with metabolic theory. Inclusion of small phytoplankton and calcifiers increase the model NPP:SST sensitivity because of their relatively higher nutrient affinity than general phytoplankton. Accounting for organic carbon "protected" from remineralization by carbonate ballast mitigates the exponential increase in NPP and provides an increasingly important pathway for deep carbon export with higher SST changes, despite simultaneous increasing carbonate dissolution rates due to ocean acidification.

  10. Impacts and effects of mesoscale ocean eddies on ocean carbon storage and atmospheric pCO2

    NASA Astrophysics Data System (ADS)

    Munday, D. R.; Johnson, H. L.; Marshall, D. P.

    2014-08-01

    An idealized numerical ocean model is used to investigate the sensitivity of the partial pressure of atmospheric carbon dioxide (pCO2) to changes in surface wind stress when mesoscale eddies are permitted in the flow. When wind stress increases, pCO_2 increases, and vice versa. The introduction of mesoscale eddies reduces the overall sensitivity of pCO2 by changing the sensitivity of ocean carbon storage due to the saturation state of carbon dioxide, the net air-sea disequilibrium, soft tissue carbon, and the carbonate pump. However, a full carbon pump decomposition shows different responses for different ocean carbon storage terms. For example, air-sea disequilibrium is actually more sensitive to increased winds at eddy-permitting resolution, whereas soft tissue carbon is much less sensitive to wind changes in an eddy-permitting ocean. Changes in pycnocline depth and the strength of both upper and lower cells of the meridional overturning circulation affect this sensitivity.

  11. Coastal Ocean Response to the Global Warming Acceleration and Hiatus

    NASA Astrophysics Data System (ADS)

    Liao, E.; Lu, W.; Yan, X. H.; Jiang, Y.; Kidwell, A. N.

    2016-02-01

    Coastlines are fundamental to humans for habitation, commerce, and natural resources. Many coastal ecosystem disasters, caused by extreme sea surface temperature (SST), were reported when the global climate shifted from global warming to global surface warming hiatus after 1998. The task of understanding the coastal SST variations within the global context is an urgent matter. Our study on the global coastal SST from 1982 to 2013 revealed a significant cooling trend in the low and mid latitudes (31.4% of the global coastlines) after 1998, while 17.9% of the global coastlines changed from a cooling trend to a warming trend concurrently. The reverse in the Northern Pacific and Atlantic coincided with the phase shift of Pacific Decadal Oscillation and North Atlantic Oscillation. These coastal SST changes are larger than the changes of the global mean and open ocean, resulting in a fast increase of extremely hot/cold days, and thus extremely hot/cold events. Meanwhile, a continuous increase of SST was detected for a considerable portion of coastlines (46.7%) with a strengthened warming along the coastlines in the high northern latitudes. Our results suggest that the global warming continued after 1998, but with a modified weaker pattern in global coastal regions.

  12. Global ocean current reconstruction from altimetric and microwave SST measurements

    NASA Astrophysics Data System (ADS)

    González-Haro, C.; Isern-Fontanet, J.

    2014-06-01

    Ocean currents are a key component to understanding many oceanic and climatic phenomena and knowledge of them is crucial for both navigation and operational applications. Currently, they are derived from Sea Surface Height (SSH) measurements provided by altimeters. However, distances between tracks and the limited number of available altimeters lead to errors in the accurate location of oceanic currents. In this study, we investigate the capability of Sea Surface Temperature (SST) observations to reconstruct surface currents at a global scale. The methodology we use consists of estimating the stream function by taking the phase from SST and the spectrum of SSH and then comparing it with altimetric measurements. Results reveal that SST provided by microwave radiometers can be used to retrieve ocean currents during winter near the major extratropical current systems, which are characterized by an intense mesoscale activity and the presence of strong thermal gradients. We have also found that surface ocean current reconstruction based on Surface Quasi-Geostrophic approach can be improved if the information about the energy spectrum provided by altimeters is used. This points to the development of a new method of reconstructing ocean currents based on the combination of the phase of SST images with the energy spectrum derived from along-track altimetric measurements.

  13. Global declines in oceanic nitrification rates as a consequence of ocean acidification

    PubMed Central

    Beman, J. Michael; Chow, Cheryl-Emiliane; King, Andrew L.; Feng, Yuanyuan; Fuhrman, Jed A.; Andersson, Andreas; Bates, Nicholas R.; Popp, Brian N.; Hutchins, David A.

    2011-01-01

    Ocean acidification produced by dissolution of anthropogenic carbon dioxide (CO2) emissions in seawater has profound consequences for marine ecology and biogeochemistry. The oceans have absorbed one-third of CO2 emissions over the past two centuries, altering ocean chemistry, reducing seawater pH, and affecting marine animals and phytoplankton in multiple ways. Microbially mediated ocean biogeochemical processes will be pivotal in determining how the earth system responds to global environmental change; however, how they may be altered by ocean acidification is largely unknown. We show here that microbial nitrification rates decreased in every instance when pH was experimentally reduced (by 0.05–0.14) at multiple locations in the Atlantic and Pacific Oceans. Nitrification is a central process in the nitrogen cycle that produces both the greenhouse gas nitrous oxide and oxidized forms of nitrogen used by phytoplankton and other microorganisms in the sea; at the Bermuda Atlantic Time Series and Hawaii Ocean Time-series sites, experimental acidification decreased ammonia oxidation rates by 38% and 36%. Ammonia oxidation rates were also strongly and inversely correlated with pH along a gradient produced in the oligotrophic Sargasso Sea (r2 = 0.87, P < 0.05). Across all experiments, rates declined by 8–38% in low pH treatments, and the greatest absolute decrease occurred where rates were highest off the California coast. Collectively our results suggest that ocean acidification could reduce nitrification rates by 3–44% within the next few decades, affecting oceanic nitrous oxide production, reducing supplies of oxidized nitrogen in the upper layers of the ocean, and fundamentally altering nitrogen cycling in the sea. PMID:21173255

  14. Importance of ice-ocean interactions for the global ocean circulation: A model study

    NASA Astrophysics Data System (ADS)

    Goosse, H.; Fichefet, T.

    1999-10-01

    Numerical experiments are conducted with a coarse-resolution global ice-ocean model in order to determine to what degree the sea ice-ocean exchanges of heat, salt/freshwater, and momentum control the general circulation of the world ocean on long timescales. These experiments reveal that the formation of North Atlantic Deep Water (NADW) in the model results from the strong heat losses that occur at the oceanic surface in the high-latitude North Atlantic. The large-scale ice-ocean interactions have nearly no influence on this process. In particular, neglecting the freshwater flux associated with the southward ice transport at Fram Strait does not impact seriously on the salinity of the Greenland and Norwegian Seas. At equilibrium the absence of this freshwater flux is balanced by an enhanced oceanic freshwater transport from the Arctic. Furthermore, it appears that the model NADW formation does not critically depend on the media (ice or ocean) transporting the freshwater. Besides, both the salt/freshwater and heat exchanges between sea ice and ocean are crucial in the Southern Ocean for the deep water production, properties, and export. The large amount of brine released during ice formation on the model Antarctic continental shelf leads to very high salinities there. The resulting dense shelf waters are then transported toward great depths after some mixing with ambient waters, finally forming the Antarctic Bottom Water body. On the other hand, the net ice melting associated with ice convergence in some areas, such as the southwestern Pacific, stabilizes the water column and forbids deep mixing in these regions. Furthermore, the contact with the ice imposes that the polar surface waters must be maintained very close to their freezing point temperature. Our results suggest that this process takes an important part in increasing the density of the Antarctic Bottom Water. We also show that the modifications of the stress at the ocean surface induced by the internal

  15. Global declines in oceanic nitrification rates as a consequence of ocean acidification.

    PubMed

    Beman, J Michael; Chow, Cheryl-Emiliane; King, Andrew L; Feng, Yuanyuan; Fuhrman, Jed A; Andersson, Andreas; Bates, Nicholas R; Popp, Brian N; Hutchins, David A

    2011-01-04

    Ocean acidification produced by dissolution of anthropogenic carbon dioxide (CO(2)) emissions in seawater has profound consequences for marine ecology and biogeochemistry. The oceans have absorbed one-third of CO(2) emissions over the past two centuries, altering ocean chemistry, reducing seawater pH, and affecting marine animals and phytoplankton in multiple ways. Microbially mediated ocean biogeochemical processes will be pivotal in determining how the earth system responds to global environmental change; however, how they may be altered by ocean acidification is largely unknown. We show here that microbial nitrification rates decreased in every instance when pH was experimentally reduced (by 0.05-0.14) at multiple locations in the Atlantic and Pacific Oceans. Nitrification is a central process in the nitrogen cycle that produces both the greenhouse gas nitrous oxide and oxidized forms of nitrogen used by phytoplankton and other microorganisms in the sea; at the Bermuda Atlantic Time Series and Hawaii Ocean Time-series sites, experimental acidification decreased ammonia oxidation rates by 38% and 36%. Ammonia oxidation rates were also strongly and inversely correlated with pH along a gradient produced in the oligotrophic Sargasso Sea (r(2) = 0.87, P < 0.05). Across all experiments, rates declined by 8-38% in low pH treatments, and the greatest absolute decrease occurred where rates were highest off the California coast. Collectively our results suggest that ocean acidification could reduce nitrification rates by 3-44% within the next few decades, affecting oceanic nitrous oxide production, reducing supplies of oxidized nitrogen in the upper layers of the ocean, and fundamentally altering nitrogen cycling in the sea.

  16. NROSS scatterometer - An instrument for global oceanic wind observations. [Navy Remote Ocean Sensing System

    NASA Technical Reports Server (NTRS)

    Li, F.; Winn, C.; Long, D.; Geuy, C.

    1984-01-01

    One of the instruments - the NROSS scatterometer or SCATT - to be launched on the Navy Remote Ocean Sensing System spacecraft in 1989 is discussed. To determine wind speed and direction that SCATT will measure the ocean normalized radar cross section (NRCS) by illuminating the ocean's surface with microwave pulses and measuring the return signal power. A wind retrieval algorithm is used to compute the wind speed and direction from the measured NRCS. Winds over at least 90 percent of the global, ice-free ocean will be observed at least once every two days. For NASA users, the system will retrieve winds with an accuracy of plus or minus 2 m/s or 10 percent whichever is greater, for wind speeds ranging from 3 to 30 m/s.

  17. A Coupled Ocean General Circulation, Biogeochemical, and Radiative Model of the Global Oceans: Seasonal Distributions of Ocean Chlorophyll and Nutrients

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Busalacchi, Antonio (Technical Monitor)

    2000-01-01

    A coupled ocean general circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability. and the interactions among three functional phytoplankton groups (diatoms. chlorophytes, and picoplankton) and three nutrients (nitrate, ammonium, and silicate). Basin scale (greater than 1000 km) model chlorophyll results are in overall agreement with CZCS pigments in many global regions. Seasonal variability observed in the CZCS is also represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are generally in conformance although occasional departures are apparent. Model nitrate distributions agree with in situ data, including seasonal dynamics, except for the equatorial Atlantic. The overall agreement of the model with satellite and in situ data sources indicates that the model dynamics offer a reasonably realistic simulation of phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent many aspects of the great diversity of physical, biological, chemical, and radiative environments encountered in the global oceans.

  18. Validation of High Resolution IMERG Satellite Precipitation over the Global Oceans using OceanRAIN

    NASA Astrophysics Data System (ADS)

    Kucera, Paul; Klepp, Christian

    2017-04-01

    Precipitation is a key parameter of the essential climate variables in the Earth System that is a key variable in the global water cycle. Observations of precipitation over oceans is relatively sparse. Satellite observations over oceans is the only viable means of measuring the spatially distribution of precipitation. In an effort to improve global precipitation observations, the research community has developed a state of the art precipitation dataset as part of the NASA/JAXA Global Precipitation Measurement (GPM) program. The satellite gridded product that has been developed is called Integrated Multi-satelliE Retrievals for GPM (IMERG), which has a maximum spatial resolution of 0.1° x 0.1° and temporal 30 minute. Even with the advancements in retrievals, there is a need to quantify uncertainty of IMERG especially over oceans. To address this need, the OceanRAIN dataset has been used to create a comprehensive database to compare IMERG products. The OceanRAIN dataset was collected using an ODM-470 optical disdrometer that has been deployed on 12 research vessels worldwide with 6 long-term installations operating in all climatic regions, seasons and ocean basins. More than 5.5 million data samples have been collected on the OceanRAIN program. These data were matched to IMERG grids for the study period of 15 March 2014-31 January 2016. This evaluation produced over a 1000 matched pairs with precipitation observed at the surface. These matched pairs were used to evaluate the performance of IMERG for different latitudinal bands and precipitation regimes. The presentation will provide an overview of the study and summary of evaluation results.

  19. Global Assessment of Exploitable Surface Reservoir Storage under Climate Change

    NASA Astrophysics Data System (ADS)

    Liu, L.; Parkinson, S.; Gidden, M.; Byers, E.; Satoh, Y.; Riahi, K.

    2016-12-01

    Surface water reservoirs provide us with reliable water supply systems, hydropower generation, flood control, and recreation services. Reliable reservoirs can be robust measures for water security and can help smooth out challenging seasonal variability of river flows. Yet, reservoirs also cause flow fragmentation in rivers and can lead to flooding of upstream areas, thereby displacing existing land-uses and ecosystems. The anticipated population growth, land use and climate change in many regions globally suggest a critical need to assess the potential for appropriate reservoir capacity that can balance rising demands with long-term water security. In this research, we assessed exploitable reservoir potential under climate change and human development constraints by deriving storage-yield relationships for 235 river basins globally. The storage-yield relationships map the amount of storage capacity required to meet a given water demand based on a 30-year inflow sequence. Runoff data is simulated with an ensemble of Global Hydrological Models (GHMs) for each of five bias-corrected general circulation models (GCMs) under four climate change pathways. These data are used to define future 30-year inflows in each river basin for time period between 2010 and 2080. The calculated capacity is then combined with geographical information of environmental and human development exclusion zones to further limit the storage capacity expansion potential in each basin. We investigated the reliability of reservoir potentials across different climate change scenarios and Shared Socioeconomic Pathways (SSPs) to identify river basins where reservoir expansion will be particularly challenging. Preliminary results suggest large disparities in reservoir potential across basins: some basins have already approached exploitable reserves, while some others display abundant potential. Exclusions zones pose significant impact on the amount of actual exploitable storage and firm yields

  20. The dependence of global ocean modeling on background diapycnal mixing.

    PubMed

    Deng, Zengan

    2014-01-01

    The Argo-derived background diapycnal mixing (BDM) proposed by Deng et al. (in publish) is introduced to and applied in Hybrid Coordinate Ocean Model (HYCOM). Sensitive experiments are carried out using HYCOM to detect the responses of ocean surface temperature and Meridional Overturning Circulation (MOC) to BDM in a global context. Preliminary results show that utilizing a constant BDM, with the same order of magnitude as the realistic one, may cause significant deviation in temperature and MOC. It is found that the dependence of surface temperature and MOC on BDM is prominent. Surface temperature is decreased with the increase of BDM, because diapycnal mixing can promote the deep cold water return to the upper ocean. Comparing to the control run, more striking MOC changes can be caused by the larger variation in BDM.

  1. An ensemble of eddy-permitting global ocean reanalyses from the MyOcean project

    NASA Astrophysics Data System (ADS)

    Masina, Simona; Storto, Andrea; Ferry, Nicolas; Valdivieso, Maria; Haines, Keith; Balmaseda, Magdalena; Zuo, Hao; Drevillon, Marie; Parent, Laurent

    2017-08-01

    A set of four eddy-permitting global ocean reanalyses produced in the framework of the MyOcean project have been compared over the altimetry period 1993-2011. The main differences among the reanalyses used here come from the data assimilation scheme implemented to control the ocean state by inserting reprocessed observations of sea surface temperature (SST), in situ temperature and salinity profiles, sea level anomaly and sea-ice concentration. A first objective of this work includes assessing the interannual variability and trends for a series of parameters, usually considered in the community as essential ocean variables: SST, sea surface salinity, temperature and salinity averaged over meaningful layers of the water column, sea level, transports across pre-defined sections, and sea ice parameters. The eddy-permitting nature of the global reanalyses allows also to estimate eddy kinetic energy. The results show that in general there is a good consistency between the different reanalyses. An intercomparison against experiments without data assimilation was done during the MyOcean project and we conclude that data assimilation is crucial for correctly simulating some quantities such as regional trends of sea level as well as the eddy kinetic energy. A second objective is to show that the ensemble mean of reanalyses can be evaluated as one single system regarding its reliability in reproducing the climate signals, where both variability and uncertainties are assessed through the ensemble spread and signal-to-noise ratio. The main advantage of having access to several reanalyses differing in the way data assimilation is performed is that it becomes possible to assess part of the total uncertainty. Given the fact that we use very similar ocean models and atmospheric forcing, we can conclude that the spread of the ensemble of reanalyses is mainly representative of our ability to gauge uncertainty in the assimilation methods. This uncertainty changes a lot from one ocean

  2. An ensemble of eddy-permitting global ocean reanalyses from the MyOcean project

    NASA Astrophysics Data System (ADS)

    Masina, Simona; Storto, Andrea; Ferry, Nicolas; Valdivieso, Maria; Haines, Keith; Balmaseda, Magdalena; Zuo, Hao; Drevillon, Marie; Parent, Laurent

    2015-07-01

    A set of four eddy-permitting global ocean reanalyses produced in the framework of the MyOcean project have been compared over the altimetry period 1993-2011. The main differences among the reanalyses used here come from the data assimilation scheme implemented to control the ocean state by inserting reprocessed observations of sea surface temperature (SST), in situ temperature and salinity profiles, sea level anomaly and sea-ice concentration. A first objective of this work includes assessing the interannual variability and trends for a series of parameters, usually considered in the community as essential ocean variables: SST, sea surface salinity, temperature and salinity averaged over meaningful layers of the water column, sea level, transports across pre-defined sections, and sea ice parameters. The eddy-permitting nature of the global reanalyses allows also to estimate eddy kinetic energy. The results show that in general there is a good consistency between the different reanalyses. An intercomparison against experiments without data assimilation was done during the MyOcean project and we conclude that data assimilation is crucial for correctly simulating some quantities such as regional trends of sea level as well as the eddy kinetic energy. A second objective is to show that the ensemble mean of reanalyses can be evaluated as one single system regarding its reliability in reproducing the climate signals, where both variability and uncertainties are assessed through the ensemble spread and signal-to-noise ratio. The main advantage of having access to several reanalyses differing in the way data assimilation is performed is that it becomes possible to assess part of the total uncertainty. Given the fact that we use very similar ocean models and atmospheric forcing, we can conclude that the spread of the ensemble of reanalyses is mainly representative of our ability to gauge uncertainty in the assimilation methods. This uncertainty changes a lot from one ocean

  3. Intercomparison of Latent Heat Fluxes Over Global Oceans

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.; Chou, Ming-Dah

    2003-01-01

    Turbulent fluxes of momentum, moisture, and heat at the air-sea interface are essential for climate studies. Version 2 Goddard Satellite-based Surface Turbulent Fluxes (GSSTF2) has been derived from the Special Sensor Microwave/Imager (SSM/I) radiance measurements. This dataset, covering the period July 1987-December 2000 over global oceans, has a spatial resolution of 1 deg x 1 deg lat-long and a temporal resolution of 1 day. Turbulent fluxes are derived from the SSM/I surface winds and surface air humidity, as well as the 2-m air and sea surface temperatures (SST) of the NCEP/NCAR reanalysis, using a bulk aerodynamic algorithm based on the surface layer similarity theory. The GSSTF2 bulk flux model, and retrieved daily wind stress, latent heat flux, wind speed, and surface air humidity validate well with ship observations of ten field experiments over the tropical and midlatitude oceans during 1991-99. The global distributions of 1988-2000 annual- and seasonal-mean turbulent fluxes show reasonable patterns related to the atmospheric general circulation and seasonal variations. Latent heat fluxes and related input parameters over global oceans during 1992-93 have been compared among GSSTF1 (version 1), GSSTF2, HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data), NCEP/NCAR reanalysis, and one based on COADS (Comprehensive Ocean-Atmosphere Data Set). Our analyses suggest that the GSSTF2 latent heat flux, surface air humidity, surface wind, and SST are quite realistic compared to the other four flux datasets examined. However, significant differences are found among these five flux datasets. The GSSTF2, available at http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/hydrology/hd_gsstf2.O.html, is useful for climate studies.

  4. Climatological distribution of aragonite saturation state in the global oceans

    NASA Astrophysics Data System (ADS)

    Jiang, Li-Qing; Feely, Richard A.; Carter, Brendan R.; Greeley, Dana J.; Gledhill, Dwight K.; Arzayus, Krisa M.

    2015-10-01

    Aragonite saturation state (Ωarag) in surface and subsurface waters of the global oceans was calculated from up-to-date (through the year of 2012) ocean station dissolved inorganic carbon (DIC) and total alkalinity (TA) data. Surface Ωarag in the open ocean was always supersaturated (Ω > 1), ranging between 1.1 and 4.2. It was above 2.0 (2.0-4.2) between 40°N and 40°S but decreased toward higher latitude to below 1.5 in polar areas. The influences of water temperature on the TA/DIC ratio, combined with the temperature effects on inorganic carbon equilibrium and apparent solubility product (K'sp), explain the latitudinal differences in surface Ωarag. Vertically, Ωarag was highest in the surface mixed layer. Higher hydrostatic pressure, lower water temperature, and more CO2 buildup from biological activity in the absence of air-sea gas exchange helped maintain lower Ωarag in the deep ocean. Below the thermocline, aerobic decomposition of organic matter along the pathway of global thermohaline circulation played an important role in controlling Ωarag distributions. Seasonally, surface Ωarag above 30° latitudes was about 0.06 to 0.55 higher during warmer months than during colder months in the open-ocean waters of both hemispheres. Decadal changes of Ωarag in the Atlantic and Pacific Oceans showed that Ωarag in waters shallower than 100 m depth decreased by 0.10 ± 0.09 (-0.40 ± 0.37% yr-1) on average from the decade spanning 1989-1998 to the decade spanning 1998-2010.

  5. Global negative emissions capacity of ocean macronutrient fertilization

    NASA Astrophysics Data System (ADS)

    Harrison, Daniel P.

    2017-03-01

    In order to meet the goal of limiting global average temperature increase to less than 2 °C, it is increasingly apparent that negative emissions technologies of up to 10 Pg C yr‑1 will be needed before the end of the century. Recent research indicates that fertilization of the ocean with the macronutrients nitrogen and phosphorus where they limit primary production, may have sequestration advantages over fertilizing iron limited regions. Utilizing global datasets of oceanographic field measurements, and output from a high resolution global circulation model, the current study provides the first comprehensive assessment of the global potential for carbon sequestration from ocean macronutrient fertilization (OMF). Sufficient excess phosphate exists outside the iron limited surface ocean to support once-off sequestration of up to 3.6 Pg C by fertilization with nitrogen. Ongoing maximum capacity of nitrogen only fertilization is estimated at 0.7 ± 0.4 Pg C yr‑1. Sequestration capacity is expected to decrease from the upper toward the lower bound over time under continued intense fertilization. If N and P were used in combination the capacity is ultimately limited by societies willingness to utilize phosphate resources. Doubling current phosphate production would allow an additional 0.9 Pg C yr‑1 and consume 0.07% yr‑1 of known global resources. Therefore offsetting up to around 15% (1.5 Pg C yr‑1) of annual global CO2 emissions is assessed as being technically plausible. Environmental risks which to date have received little quantitative evaluation, could also limit the scale of implementation. These results reinforce the need to consider a multi-faceted approach to greenhouse gasses, including a reduction in emissions coupled with further research into negative emissions technologies.

  6. Enceladus's measured physical libration requires a global subsurface ocean

    NASA Astrophysics Data System (ADS)

    Thomas, P. C.; Tajeddine, R.; Tiscareno, M. S.; Burns, J. A.; Joseph, J.; Loredo, T. J.; Helfenstein, P.; Porco, C.

    2016-01-01

    Several planetary satellites apparently have subsurface seas that are of great interest for, among other reasons, their possible habitability. The geologically diverse saturnian satellite Enceladus vigorously vents liquid water and vapor from fractures within a south polar depression and thus must have a liquid reservoir or active melting. However, the extent and location of any subsurface liquid region is not directly observable. We use measurements of control points across the surface of Enceladus accumulated over seven years of spacecraft observations to determine the satellite's precise rotation state, finding a forced physical libration of 0.120 ± 0.014° (2σ). This value is too large to be consistent with Enceladus's core being rigidly connected to its surface, and thus implies the presence of a global ocean rather than a localized polar sea. The maintenance of a global ocean within Enceladus is problematic according to many thermal models and so may constrain satellite properties or require a surprisingly dissipative Saturn.

  7. A daily global mesoscale ocean eddy dataset from satellite altimetry

    PubMed Central

    Faghmous, James H.; Frenger, Ivy; Yao, Yuanshun; Warmka, Robert; Lindell, Aron; Kumar, Vipin

    2015-01-01

    Mesoscale ocean eddies are ubiquitous coherent rotating structures of water with radial scales on the order of 100 kilometers. Eddies play a key role in the transport and mixing of momentum and tracers across the World Ocean. We present a global daily mesoscale ocean eddy dataset that contains ~45 million mesoscale features and 3.3 million eddy trajectories that persist at least two days as identified in the AVISO dataset over a period of 1993–2014. This dataset, along with the open-source eddy identification software, extract eddies with any parameters (minimum size, lifetime, etc.), to study global eddy properties and dynamics, and to empirically estimate the impact eddies have on mass or heat transport. Furthermore, our open-source software may be used to identify mesoscale features in model simulations and compare them to observed features. Finally, this dataset can be used to study the interaction between mesoscale ocean eddies and other components of the Earth System. PMID:26097744

  8. Ocean Biogeochemistry and Phytoplankton Ecology in a Global Simulation

    NASA Astrophysics Data System (ADS)

    Moore, J. K.; Doney, S. C.; Lindsay, K.

    2005-05-01

    A coupled Biogeochemistry/Ecosystem/Circulation (BEC) model is used to examine ocean biogeochemistry and phytoplankton ecology at the global scale. Phytoplankton groups represented in the model include diatoms, diazotrophs, coccolithophores and picoplankton. The groups experience differential grazing pressure and compete for light and the potentially growth-limiting nutrients iron, nitrate, ammonium, phosphate, and silicate. The model includes several key aspects of the global nitrogen cycle including nitrogen fixation (by the diazotrophs), water column denitrification under low oxygen conditions, and atmospheric nitrogen deposition to the oceans. We examine how these nitrogen fluxes influence ecosystem structure and also how light and nutrient availability restrict phytoplankton growth rates over seasonal timescales. Atmospheric deposition of mineral dust also inputs dissolved iron to the ocean model. These iron additions modify phytoplankton community composition, and rates of production and export in the iron-limited High Nitrate, Low Chlorophyll regions, and indirectly modify ecosystem dynamics by altering rates of nitrogen fixation in nitrogen-depleted, tropical and subtropical regions. We will examine the links between dust/iron deposition and nitrogen cycling in the oceans.

  9. The new automatic precipitation phase distinction algorithm for OceanRAIN data over the global ocean

    NASA Astrophysics Data System (ADS)

    Burdanowitz, Jörg; Klepp, Christian; Bakan, Stephan

    2015-04-01

    The hitherto lack of surface precipitation data over the global ocean limits the capabilities to validate recent and future precipitation satellite retrievals. The first systematic ship-based surface precipitation data set OceanRAIN (Ocean Rain And Ice-phase precipitation measurement Network) aims at providing in-situ precipitation data through particle size distributions (PSDs) from optical disdrometers deployed on research vessels (RVs). From the RV Polarstern, OceanRAIN currently contains more than four years of 1-minute resolution precipitation data, which corresponds to more than 200,000 minutes of precipitation. The calculation of the precipitation rate requires to know the precipitation phase (PP) of the falling particles. We develop a novel algorithm to automatically retrieve the PP using OceanRAIN data and ancillary meteorological measurements from RVs. The main objective is to improve accuracy and efficiency of the current time-consuming manual method of discriminating liquid and solid precipitation particles. The new PP distinction algorithm is based on the relation of air temperature and relative humidity (T-rH) with respect to PP. For first-time usage over oceanic areas, the land-retrieved coefficients of this empirical relationship are adjusted to OceanRAIN data. The measured PSD supports determining the PP in certain cases where large snow aggregates exist at distinctly positive air temperatures. The classification, based on T-rH and PSD, is statistically exploited and weighed with respect to the current weather conditions to obtain an overall PP probability at 1-minute resolution. The new PP distinction algorithm agrees in more than 92% (94% excl. mixed-phase) of precipitating cases with the manually-determined PP in the RV Polarstern data. The PP distinction algorithm complements the valuable information of OceanRAIN surface precipitation over the ocean.

  10. Satellite-Based Daily SSTs Over the Global Ocean

    DTIC Science & Technology

    2006-08-03

    combination of optimal interpolation and climatologically corrected persistence balances eddy resolving spatial and daily temporal resolution with improved...SST fields over the global resolving spatial and daily temporal resolution with ocean on time scales ranging from daily to annual from improved...measurements, drifting buoys, etc., do not provide enough [6] The AVHRR sensor is sensitive to the presence of spatial and temporal coverage over the

  11. Why ocean heat transport warms the global mean climate

    NASA Astrophysics Data System (ADS)

    Herweijer, Celine; Seager, Richard; Winton, Michael; Clement, Amy

    2005-08-01

    Observational and modelling evidence suggest that poleward ocean heat transport (OHT) can vary in response to both natural climate variability and greenhouse warming. Recent modelling studies have shown that increased OHT warms both the tropical and global mean climates. Using two different coupled climate models with mixed-layer oceans, with and without OHT, along with a coupled model with a fixed-current ocean component in which the currents are uniformly reduced and increased by 50%, an attempt is made to explain why this may happen.OHT warms the global mean climate by 1 to 1.6K in the atmospheric general circulation (AGCM) ML model and 3.5K in the AGCM fixed current model. In each model the warming is attributed to an increase in atmospheric greenhouse trapping, primarily clear-sky greenhouse trapping, and a reduction in albedo. This occurs as OHT moistens the atmosphere, particularly at subtropical latitudes. This is not purely a thermodynamic response to the reduction in planetary albedo at these latitudes. It is a change in atmospheric circulation that both redistributes the water vapour and allows for a global atmospheric moistening—a positive 'dynamical' water vapour feedback. With increasing OHT the atmospheric water vapour content increases as atmospheric convection spreads out of the deep tropics. The global mean planetary albedo is decreased with increased OHT. This change is explained by a decrease in subtropical and mid-latitude low cloudiness, along with a reduction in high-latitude surface albedo due to decreased sea ice. The climate models with the mixed layer oceans underestimate both the subtropical low cloud cover and the high-latitude sea ice/surface albedo, and consequently have a smaller warming response to OHT.

  12. Energetics of global ocean tides from Geosat altimetry

    NASA Technical Reports Server (NTRS)

    Cartwright, David E.; Ray, Richard D.

    1991-01-01

    The present paper focuses on resonance and energetics of the daily tides, especially in the southern ocean, the distribution of gravitational power input of daily and half-daily tides, and comparison with other estimates of global dissipation rates. The present global tidal maps, derived from Geosat altimetry, compare favorably with ground truth data at about the same rms level as the models of Schwiderski (1983), and are slightly better in lunar than in solar tides. Diurnal admittances clearly show Kelvin wave structure in the southern ocean and confirm the resonant mode of Platzman (1984) at 28.5 + or - 0.1 hr with an apparent Q of about 4. Driving energy is found to enter dominantly in the North Pacific for the daily tides and is strongly peaked in the tropical oceans for the half-daily tides. Global rates of working on all major tide constituents except S2 agree well with independent results from analyses of gravity through satellite tracking. Comparison at S2 is improved by allowing for the air tide in gravitational results but suggests deficiencies in all solar tide models.

  13. A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP)

    SciTech Connect

    Key, Robert; Kozyr, Alexander; Sabine, Chris; Lee, K.; Wanninkhof, R.; Bullister, J.L.; Feely, R. A.; Millero, F. J.; Mordy, C.; Peng, T.-H.

    2004-01-01

    During the 1990s, ocean sampling expeditions were carried out as part of the World Ocean Circulation Experiment (WOCE), the Joint Global Ocean Flux Study (JGOFS), and the Ocean Atmosphere Carbon Exchange Study (OACES). Subsequently, a group of U.S. scientists synthesized the data into easily usable and readily available products. This collaboration is known as the Global Ocean Data Analysis Project (GLODAP). Results were merged into a common format data set, segregated by ocean. For comparison purposes, each ocean data set includes a small number of high-quality historical cruises. The data were subjected to rigorous quality control procedures to eliminate systematic data measurement biases. The calibrated 1990s data were used to estimate anthropogenic CO{sub 2}, potential alkalinity, CFC watermass ages, CFC partial pressure, bomb-produced radiocarbon, and natural radiocarbon. These quantities were merged into the measured data files. The data were used to produce objectively gridded property maps at a 1{sup o} resolution on 33 depth surfaces chosen to match existing climatologies for temperature, salinity, oxygen, and nutrients. The mapped fields are interpreted as an annual mean distribution in spite of the inaccuracy in that assumption. Both the calibrated data and the gridded products are available from the Carbon Dioxide Information Analysis Center. Here we describe the important details of the data treatment and the mapping procedure, and present summary quantities and integrals for the various parameters.

  14. El Nino and the Global Ocean Observing System

    NASA Technical Reports Server (NTRS)

    Halpern, David

    1999-01-01

    Until a decade ago, an often-quoted expression in oceanography is that very few observations are recorded throughout the ocean. Now, the sentiment is no longer valid in the uppermost 10% of the tropical Pacific Ocean nor at the surface of the global ocean. One of the remarkable legacies of the 1985-1994 Tropical Oceans Global Atmosphere (TOGA) Program is an in situ marine meteorological and upper oceanographic measurement array throughout the equatorial Pacific to monitor the development and maintenance of El Nino episodes. The TOGA Observing System, which initially consisted of moored- and drifting-buoy arrays, a network of commercial ships, and coastal and island stations, now includes a constellation of satellites and data-assimilating models to simulate subsurface oceanographic conditions. The El Nino and La Nina tropical Pacific Ocean observing system represents the initial phase of an integrated global ocean observing system. Remarkable improvements have been made in ocean model simulation of subsurface currents, but some problems persist. For example, the simulation of the South Equatorial Current (SEC) remains an important challenge in the 2S-2N Pacific equatorial wave guide. During El Nino the SEC at the equator is reduced and sometimes the direction is reversed, becoming eastward. Both conditions allow warm water stored in the western Pacific to invade the eastern region, creating an El Nino episode. Assimilation of data is a tenet of faith to correct simulation errors caused by deficiencies in surface fluxes (especially wind stress) and parameterizations of subgrid-scale physical processes. In the first of two numerical experiments, the Pacific SEC was simulated with and without assimilation of subsurface temperature data. Along the equator, a very weak SEC occurred throughout the eastern Pacific, independent of assimilation of data. However, as displayed in the diagram, in the western Pacific there was no satisfactory agreement between the two

  15. El Nino and the Global Ocean Observing System

    NASA Technical Reports Server (NTRS)

    Halpern, David

    1999-01-01

    Until a decade ago, an often-quoted expression in oceanography is that very few observations are recorded throughout the ocean. Now, the sentiment is no longer valid in the uppermost 10% of the tropical Pacific Ocean nor at the surface of the global ocean. One of the remarkable legacies of the 1985-1994 Tropical Oceans Global Atmosphere (TOGA) Program is an in situ marine meteorological and upper oceanographic measurement array throughout the equatorial Pacific to monitor the development and maintenance of El Nino episodes. The TOGA Observing System, which initially consisted of moored- and drifting-buoy arrays, a network of commercial ships, and coastal and island stations, now includes a constellation of satellites and data-assimilating models to simulate subsurface oceanographic conditions. The El Nino and La Nina tropical Pacific Ocean observing system represents the initial phase of an integrated global ocean observing system. Remarkable improvements have been made in ocean model simulation of subsurface currents, but some problems persist. For example, the simulation of the South Equatorial Current (SEC) remains an important challenge in the 2S-2N Pacific equatorial wave guide. During El Nino the SEC at the equator is reduced and sometimes the direction is reversed, becoming eastward. Both conditions allow warm water stored in the western Pacific to invade the eastern region, creating an El Nino episode. Assimilation of data is a tenet of faith to correct simulation errors caused by deficiencies in surface fluxes (especially wind stress) and parameterizations of subgrid-scale physical processes. In the first of two numerical experiments, the Pacific SEC was simulated with and without assimilation of subsurface temperature data. Along the equator, a very weak SEC occurred throughout the eastern Pacific, independent of assimilation of data. However, as displayed in the diagram, in the western Pacific there was no satisfactory agreement between the two

  16. Validation of a global finite element sea-ice ocean model

    NASA Astrophysics Data System (ADS)

    Timmermann, R.; Danilov, S.; Schröter, J.

    2009-04-01

    Results from a global Finite Element Sea ice-Ocean Model (FESOM) are evaluated using a wide range of observational datasets. FESOM's ocean component is a primitive-equation, hydrostatic ocean model using isopycnic diffusion and a Gent-McWilliams scheme to parameterize the effects of sub-gridscale turbulence on tracer distribution. Vertical mixing and convection are parameterized as a function of the Richardson number and the Monin-Obukhov length. A finite element dynamic-thermodynamic sea ice-model with elastic-viscous-plastic rheology has been developed and coupled to the ocean component. The model features a prognostic snow layer but neglects internal heat storage. All model components are discretized on a triangular/tetrahedral grid with a continuous, conforming representation of model variables. The coupled model has been run in a global configuration and forced with NCEP daily atmospheric reanalysis data for 1948-2007. Results are analysed with a focus on the Southern Hemisphere. While summer ice extent is underestimated in both hemispheres, winter ice extents are in good agreement with satellite data. Southern Ocean sea ice thickness distribution agrees well with ship-based observations and even quantitatively with data from upwards looking sonars (ULS). Sea ice freezing rates have been validated using repeated salinity profiles from Southern Elephant Seals. Gulf Stream transport is underestimated, but transports of the Kuroshio and the Antarctic Circumpolar Current appear realistic. A comparison of numerical tracer studies to observed CFC distribution indicates that bottom layer ventilation occurs on realistic pathways. Global meridional overturning features a strong Antarctic Bottom Water (AABW) cell, while the formation of North Atlantic Deep Water (NADW) appears to be on the weak side. Besides pure model validation, the study also identifies regions and processes that critically require a locally increased horizontal resolution in order to be represented

  17. Geological storage of CO2 within the oceanic crust by gravitational trapping

    NASA Astrophysics Data System (ADS)

    Marieni, Chiara; Henstock, Timothy J.; Teagle, Damon A. H.

    2013-12-01

    rise of atmospheric carbon dioxide (CO2) principally due to the burning of fossil fuels is a key driver of anthropogenic climate change. Mitigation strategies include improved efficiency, using renewable energy, and capture and long-term sequestration of CO2. Most sequestration research considers CO2 injection into deep saline aquifers or depleted hydrocarbon reservoirs. Unconventional suggestions include CO2 storage in the porous volcanic lavas of uppermost oceanic crust. Here we test the feasibility of injecting CO2 into deep-sea basalts and identify sites where CO2 should be both physically and gravitationally trapped. We use global databases to estimate pressure and temperature, hence density of CO2 and seawater at the sediment-basement interface. At previously suggested sites on the Juan de Fuca Plate and in the eastern equatorial Pacific Ocean, CO2 is gravitationally unstable. However, we identify five sediment-covered regions where CO2 is denser than seawater, each sufficient for several centuries of anthropogenic CO2 emissions.

  18. Tara Oceans' approach and new challenges in studying the ocean microbiome at global scale

    NASA Astrophysics Data System (ADS)

    Coelho, L. P.; Sunagawa, S.; Chaffron, S.; Bowler, C.; Winker, P.; Karsenti, E.; Raes, J.; Acinas, S. G.; Bork, P.

    2016-02-01

    Drawing an ecosystem-wide picture of community structure, functional diversity and ecological drivers of the ocean microbiome has been a grand challenge. This has been primarily due to the lack of a systematically collected set of samples with associated environmental information at global scale. To address this limitation, Tara Oceans has so far collected more than 35,000 samples for genomic, morphological and environmental analyses from all major oceanic regions. Using an eco-systems biology approach, we analyzed 7.2 terabases of metagenomic data from 243 water samples that were collected at multiple depths to determine the main stratifying factors and environmental drivers of ocean microbial community structure and function. To this end, we constructed and annotated an ocean microbial reference gene catalog with >40 million non-redundant, mostly novel sequences from viruses, prokaryotes and picoeukaryotes. A focus on 139 prokaryote-enriched samples revealed microbiota to be primarily stratified into epipelagic and mesopelagic communities. For epipelagic communities, we disentangled co-correlations of environmental parameters and identified microbial communities composition to be mainly driven by temperature rather than geography. To resolve this overall pattern from community to species-level, we reconstructed clusters of core genes of dominant ocean microbial species and investigate their biogeography based on metagenomic profiling of single nucleotide polymorphisms. The integration of metatranscriptomic data is adding an additional layer of information to study their activity as a function of physicochemical differences of their environment.

  19. Variability in global ocean phytoplankton distribution over 1979-2007

    NASA Astrophysics Data System (ADS)

    Masotti, I.; Alvain, S.; Moulin, C.; Antoine, D.

    2009-04-01

    Recently, reanalysis of long-term ocean color data (CZCS and SeaWiFS; Antoine et al., 2005) has shown that world ocean average phytoplankton chlorophyll levels show an increase of 20% over the last two decades. It is however unknown whether this increase is associated with a change in the distribution of phytoplankton groups or if it simply corresponds to an increase of the productivity. Within the framework of the GLOBPHY project, the distribution of the phytoplankton groups was monitored by applying the PHYSAT method (Alvain et al., 2005) to the historical ocean color data series from CZCS, OCTS and SeaWiFS sensors. The PHYSAT algorithm allows identification of several phytoplankton, like nanoeucaryotes, prochlorococcus, synechococcus and diatoms. Because both sensors (OCTS-SeaWiFS) are very similar, OCTS data were processed with the standard PHYSAT algorithm to cover the 1996-1997 period during which a large El Niño event occurred, just before the SeaWiFS era. Our analysis of this dataset (1996-2006) evidences a strong variability in the distribution of phytoplankton groups at both regional and global scales. In the equatorial region (0°-5°S), a three-fold increase of nanoeucaryotes frequency was detected in opposition to a two-fold decrease of synechococcus during the early stages of El Niño conditions (May-June 1997, OCTS). The impact of this El Niño is however not confined to the Equatorial Pacific and has affected the global ocean. The processing of CZCS data with PHYSAT has required several adaptations of this algorithm due to the lower performances and the reduced number of spectral bands of the sensor. Despites higher uncertainties, the phytoplankton groups distribution obtained with CZCS is globally consistent with that of SeaWiFS. A comparison of variability in global phytoplankton distribution between 1979-1982 (CZCS) and 1999-2002 (SeaWiFS) suggests an increase in nanoeucaryotes at high latitudes (>40°) and in the equatorial region (10°S-10

  20. A simulation of the global ocean circulation with resolved eddies

    NASA Astrophysics Data System (ADS)

    Semtner, Albert J.; Chervin, Robert M.

    1988-12-01

    A multilevel primitive-equation model has been constructed for the purpose of simulating ocean circulation on modern supercomputing architectures. The model is designed to take advantage of faster clock speeds, increased numbers of processors, and enlarged memories of machines expected to be available over the next decade. The model allows global eddy-resolving simulations to be conducted in support of the World Ocean Circulation Experiment. Furthermore, global ocean modeling is essential for proper representation of the full range of oceanic and climatic phenomena. The first such global eddy-resolving ocean calculation is reported here. A 20-year integration of a global ocean model with ½° grid spacing and 20 vertical levels has been carried out with realistic geometry and annual mean wind forcing. The temperature and salinity are constrained to Levitus gridded data above 25-m depth and below 710-m depth (on time scales of 1 month and 3 years, respectively), but the values in the main thermocline are unconstrained for the last decade of the calculation. The final years of the simulation allow the spontaneous formation of waves and eddies through the use of scale-selective viscosity and diffusion. A quasi-equilibrium state shows many realistic features of ocean circulation, including unstable separating western boundary currents, the known anomalous northward heat transport in the South Atlantic, and a global compensation for the abyssal spread of North Atlantic Deep Water via a long chain of thermocline mass transport from the tropical Pacific, through the Indonesian archipelago, across the Indian Ocean, and around the southern tip of Africa. This chain of thermocline transport is perhaps the most striking result from the model, and eddies and waves are evident along the entire 20,000-km path of the flow. The modeled Gulf Stream separates somewhat north of Cape Hatteras, produces warm- and cold-core rings, and maintains its integrity as a meadering thermal front

  1. Control of ocean carbon storage and atmospheric pCO2 by Southern Ocean sea ice dynamics

    NASA Astrophysics Data System (ADS)

    Zakem, E.; Ferreira, D.; Follows, M. J.

    2012-12-01

    Change in annual sea ice in the Southern ocean has been proposed as a control on atmospheric pCO2 levels since Antarctic glacial inception around 34 Ma. Sea ice coverage slows or prevents the degassing of carbon-rich upwelled water, increasing ocean carbon storage, though the significance of this process has been doubted due to the coincidental decrease of the biological pump with ice cover. Here we explore the mechanism by which southern ocean sea ice coverage and dynamics drive atmospheric pCO2 levels in the Southern Ocean. To this end, we analyze the biogeochemical output of coupled ocean-atmosphere-sea ice GCM models with simplified geometry. Bottom water formation rates are controlled by manipulating ice dynamics. We show that the dominant difference in the ocean carbon content between model states is mainly driven by air-sea disequilibrium, rather than by solubility or biological productivity. As bottom water formation strengthens, the overturning cell underneath the sea ice is enriched in DIC at depth, but ice cover prevents outgassing to the atmosphere upon return to the surface. When bottom water is present, the ocean fills with carbon-rich water, driving down atmospheric pCO2. Our results suggest that it is the processes driving sea ice production on Antarctica continental margins such as atmospheric circulation and ice-shelf interaction that influence ocean carbon storage, rather than solely the existence of sea ice. This suggests the mechanism by which the onset of Antarctic Bottom Water formation after the opening of the Southern ocean gateways may have served as a positive feedback to decreasing pCO2 and a cooling climate.

  2. Penetration of UV irradiance into the global ocean

    NASA Astrophysics Data System (ADS)

    Smyth, T. J.

    2011-11-01

    A new global ocean-atmosphere model has been developed to determine the penetration of ultraviolet (UV) radiation through the water column. This is accomplished by combining an atmospheric UV irradiance model, taking into consideration the effects of aerosols, clouds, and the air-sea interface, with empirical in-water diffuse attenuation coefficient (Kd(λUV)) relationships. These empirical relationships are derived from simultaneous in situ profiles of visible wavelength inherent optical properties and downwelling UV irradiances. The combined model is applied to global data sets using a look-up table approach to speed up calculation time. The atmospheric model compared against ˜3000 data points gave a root-mean-square error (RMSE) of between 10% and 15% at wavelengths of 305, 325, 340, and 380 nm; the coupled global model compared against 30 independent in-water irradiance profiles gave a logarithmic RMSE of between 0.15 and 0.35 at these wavelengths. On the global scale the 10% irradiance levels were found to be deepest in the oceanic gyres (˜18, 32, 44, and 70 m at 305, 325, 340 and 380 nm, respectively) and shallowest in the optically complex continental shelf regions. The calculated UV doses were shown to be spectrally and seasonally variable, with the highest values being encountered in the eastern Mediterranean during July, with values of ˜0.5, 4, 7, and 10 kJ m-2 d-1 nm-1 at 305, 325, 340, and 380 nm, respectively.

  3. The MERCATOR 2 degree global ocean forecasting system

    NASA Astrophysics Data System (ADS)

    Ferry, N.; Tranchant, B.; Durand, E.

    2003-04-01

    In the framework of the MERCATOR project for operational oceanography, a global ocean forecasting system is being developed. It will be composed of a 1/4o resolution model assimilating satellite and in situ observations, using an optimal interpolation scheme. This global forecasting system, Prototype d'Océan Global (POG) should be running in a pre-operational mode during the GODAE period. In order to assess the feasibility, a lower resolution (~2o) configuration of the system, mini-POG is also developed and is underway to be operated in near real time. Both configurations (POG and mini-POG) are based on the OPA8.2 ocean model (Madec et al. 1998). The 2o configuration (the mini-POG model) is the standard global configuration (ORCA2) developed at LODYC (Paris). The assimilation method used is the reduced-order optimal interpolation (OI) scheme SOFA (De Mey and Benkiran, 2002) which is able to incorporate both altimeter and in situ observations. Up to now only the sea level anomaly from Topex-Poseidon &ERS2 measurements along tracks is assimilated with an univariate mode. The 2D increments of SLA are converted into 3D increments of T, S, U, V and TKE coefficients using an algorithm based on the lifting-lowering method of Cooper and Haines (1996). The PALM software enables to drive easily the ocean model, the assimilation and the observations. The model is spun up with the ERA15 reanalyses climatology. Then, it is forced with interannual surface forcing (ECMWF operational analyses) during several years of the Topex- Poseidon period. A Mean Sea Surface Height and spatial/temporal correlation scales is obtained and used to constrain the assimilation. The preliminary results of the system including assimilation of Topex-Poseidon &ERS2 sea level anomaly are presented.

  4. Observed and modeled global-ocean turbulence regimes as deduced from surface trajectory data

    NASA Astrophysics Data System (ADS)

    Nilsson, Jenny A. U.; Döös, Kristofer; Ruti, Paolo Michele; Artale, Vincenzo; Coward, Andrew; Brodeau, Laurent

    2013-04-01

    fields since high-resolution data require considerable amounts of storage space. Here, the implications of such approximations on the modeled velocity fields and, consequently, on the particle dispersion, have been assessed through the validation against observed drifter tracks. This study aims, moreover, to shed some light on the relatively unknown turbulent properties of the near-surface ocean dynamics and its representation in numerical models globally and in a number of key regions. These results could be of interest for other studies within the field of turbulent eddy-diffusion parameterization in ocean models, or ocean circulation studies involving long-term coarse-grid model experiments.

  5. Global Ocean Integrals and Means, with Trend Implications.

    PubMed

    Wunsch, Carl

    2016-01-01

    Understanding the ocean requires determining and explaining global integrals and equivalent average values of temperature (heat), salinity (freshwater and salt content), sea level, energy, and other properties. Attempts to determine means, integrals, and climatologies have been hindered by thinly and poorly distributed historical observations in a system in which both signals and background noise are spatially very inhomogeneous, leading to potentially large temporal bias errors that must be corrected at the 1% level or better. With the exception of the upper ocean in the current altimetric-Argo era, no clear documentation exists on the best methods for estimating means and their changes for quantities such as heat and freshwater at the levels required for anthropogenic signals. Underestimates of trends are as likely as overestimates; for example, recent inferences that multidecadal oceanic heat uptake has been greatly underestimated are plausible. For new or augmented observing systems, calculating the accuracies and precisions of global, multidecadal sampling densities for the full water column is necessary to avoid the irrecoverable loss of scientifically essential information.

  6. Antarctic and Southern Ocean influences on Late Pliocene global cooling.

    PubMed

    McKay, Robert; Naish, Tim; Carter, Lionel; Riesselman, Christina; Dunbar, Robert; Sjunneskog, Charlotte; Winter, Diane; Sangiorgi, Francesca; Warren, Courtney; Pagani, Mark; Schouten, Stefan; Willmott, Veronica; Levy, Richard; DeConto, Robert; Powell, Ross D

    2012-04-24

    The influence of Antarctica and the Southern Ocean on Late Pliocene global climate reconstructions has remained ambiguous due to a lack of well-dated Antarctic-proximal, paleoenvironmental records. Here we present ice sheet, sea-surface temperature, and sea ice reconstructions from the ANDRILL AND-1B sediment core recovered from beneath the Ross Ice Shelf. We provide evidence for a major expansion of an ice sheet in the Ross Sea that began at ∼3.3 Ma, followed by a coastal sea surface temperature cooling of ∼2.5 °C, a stepwise expansion of sea ice, and polynya-style deep mixing in the Ross Sea between 3.3 and 2.5 Ma. The intensification of Antarctic cooling resulted in strengthened westerly winds and invigorated ocean circulation. The associated northward migration of Southern Ocean fronts has been linked with reduced Atlantic Meridional Overturning Circulation by restricting surface water connectivity between the ocean basins, with implications for heat transport to the high latitudes of the North Atlantic. While our results do not exclude low-latitude mechanisms as drivers for Pliocene cooling, they indicate an additional role played by southern high-latitude cooling during development of the bipolar world.

  7. Antarctic and Southern Ocean influences on Late Pliocene global cooling

    USGS Publications Warehouse

    McKay, Robert; Naish, Tim; Carter, Lionel; Riesselman, Christina; Dunbar, Robert; Sjunneskog, Charlotte; Winter, Diane; Sangiorgi, Francesca; Warren, Courtney; Pagani, Mark; Schouten, Stefan; Willmott, Veronica; Levy, Richard; DeConto, Robert; Powell, Ross D.

    2012-01-01

    The influence of Antarctica and the Southern Ocean on Late Pliocene global climate reconstructions has remained ambiguous due to a lack of well-dated Antarctic-proximal, paleoenvironmental records. Here we present ice sheet, sea-surface temperature, and sea ice reconstructions from the ANDRILL AND-1B sediment core recovered from beneath the Ross Ice Shelf. We provide evidence for a major expansion of an ice sheet in the Ross Sea that began at ~3.3 Ma, followed by a coastal sea surface temperature cooling of ~2.5 °C, a stepwise expansion of sea ice, and polynya-style deep mixing in the Ross Sea between 3.3 and 2.5 Ma. The intensification of Antarctic cooling resulted in strengthened westerly winds and invigorated ocean circulation. The associated northward migration of Southern Ocean fronts has been linked with reduced Atlantic Meridional Overturning Circulation by restricting surface water connectivity between the ocean basins, with implications for heat transport to the high latitudes of the North Atlantic. While our results do not exclude low-latitude mechanisms as drivers for Pliocene cooling, they indicate an additional role played by southern high-latitude cooling during development of the bipolar world.

  8. Attenuation coefficient of usable solar radiation of the global oceans

    NASA Astrophysics Data System (ADS)

    Lin, Junfang; Lee, Zhongping; Ondrusek, Michael; Kahru, Mati

    2016-05-01

    Usable solar radiation (USR) represents spectrally integrated solar energy in the spectral range of 400-560 nm, a domain where photons penetrate the most in oceanic waters and thus contribute to photosynthesis and heating at deeper depths. Through purely numerical simulations, it was found that the diffuse attenuation coefficient of downwelling USR (Kd(USR), m-1) is nearly a constant vertically in the upper water column for clear waters and most turbid waters. Subsequently an empirical model was developed to estimate Kd(USR) based on the diffuse attenuation coefficient at 490 nm (Kd(490), m-1). We here evaluate this relationship using data collected from a wide range of oceanic and coastal environments and found that the relationship between Kd(490) and Kd(USR) developed via the numerical simulation is quite robust. We further refined this relationship to extend the applicability to "clearest" natural waters. This refined relationship was then used to produce sample distribution of Kd(USR) of global oceans. As expected, extremely low Kd(USR) (˜0.02 m-1) was observed in ocean gyres, while significantly higher Kd(USR) (˜5.2 m-1) was found in very turbid coastal regions. A useful application of Kd(USR) is to easily and accurately propagate surface USR to deeper depths, potentially to significantly improve the estimation of basin scale primary production and heat fluxes in the upper water column.

  9. Global coupling and decoupling of the APS storage ring

    SciTech Connect

    Chae, Y.C.; Liu, J.; Teng, L.C.

    1993-07-01

    This paper describes a study of controlling the coupling between the horizontal and the vertical betatron oscillations in the 7-GeV Advanced Photon Source (APS) storage ring. First, we investigate the strengthening of coupling using two families of skew quadrupoles. Twenty skew quadrupoles are arranged in the 40 sectors of the storage ring and powered in such a way so as to generate both quadrature components of the required 21st harmonic. The numerical results from tracking a single particle are presented for the various configurations of skew quadrupoles. Second, we describe the global decoupling procedure to minimize the unwanted coupling effects. These are mainly due to the random roll errors of normal quadruples. It is shown that even with the rather large rms roll error of 2 mrad, the coupling effects can be compensated for with 20 skew quadrupoles each having maximum strength one order of magnitude lower than the typical normal quadrupole strength.

  10. The global potential for carbon capture and storage from forestry.

    PubMed

    Ni, Yuanming; Eskeland, Gunnar S; Giske, Jarl; Hansen, Jan-Petter

    2016-12-01

    Discussions about limiting anthropogenic emissions of CO[Formula: see text] often focus on transition to renewable energy sources and on carbon capture and storage (CCS) of CO[Formula: see text]. The potential contributions from forests, forest products and other low-tech strategies are less frequently discussed. Here we develop a new simulation model to assess the global carbon content in forests and apply the model to study active annual carbon harvest 100 years into the future. The numerical experiments show that under a hypothetical scenario of globally sustainable forestry the world's forests could provide a large carbon sink, about one gigatonne per year, due to enhancement of carbon stock in tree biomass. In addition, a large amount of wood, 11.5 GT of carbon per year, could be extracted for reducing CO[Formula: see text] emissions by substitution of wood for fossil fuels. The results of this study indicate that carbon harvest from forests and carbon storage in living forests have a significant potential for CCS on a global scale.

  11. Subsurface Ocean Climate Data Records: Global Ocean Heat and Freshwater Content

    NASA Astrophysics Data System (ADS)

    Boyer, T.; Locarnini, R. A.; Mishonov, A. V.; Reagan, J. R.

    2015-12-01

    The ocean is the main sink of excess heat in the Earth's climate system. It absorbs more than 90% of the Top of the Atmosphere imbalance between incoming solar radiation and outgoing long-wave radiation. The ocean, covering more than 70% of the Earth's surface, is also the major component of the planet's freshwater cycle. More than 60 years of in situ subsurface temperature and salinity data have been compiled and quality controlled in World Ocean Database of the National Centers for Environmental Information. These data have been used to calculate time series of global heat and salt changes in the ocean. Salt changes can be used to calculate freshwater changes, including from melting continental glaciers. Both time series provide a measure of the changes in the Earth's climate system: from heat sequestered in the ocean, to the rise of sea level due to thermosteric and halosteric components. The time series are updated every three months and are widely used in climate related studies. Method of quality control of the data, calculation of the time series, and dissemination and use of the time series are discussed.

  12. Assimilation of GRACE-derived oceanic mass distributions with a global ocean circulation model

    NASA Astrophysics Data System (ADS)

    Saynisch, J.; Bergmann-Wolf, I.; Thomas, M.

    2015-02-01

    To study the sub-seasonal distribution and generation of ocean mass anomalies, Gravity Recovery and Climate Experiment (GRACE) observations of daily and monthly resolution are assimilated into a global ocean circulation model with an ensemble-based Kalman-Filter technique. The satellite gravimetry observations are processed to become time-variable fields of ocean mass distribution. Error budgets for the observations and the ocean model's initial state are estimated which contain the full covariance information. The consistency of the presented approach is demonstrated by increased agreement between GRACE observations and the ocean model. Furthermore, the simulations are compared with independent observations from 54 bottom pressure recorders. The assimilation improves the agreement to high-latitude recorders by up to 2 hPa. The improvements are caused by assimilation-induced changes in the atmospheric wind forcing, i.e., quantities not directly observed by GRACE. Finally, the use of the developed Kalman-Filter approach as a destriping filter to remove artificial noise contaminating the GRACE observations is presented.

  13. Ocean Carbon Cycle Data from the Joint Global Ocean Flux Study (JGOFS)

    DOE Data Explorer

    The U.S. JGOFS program, a component of the U.S Global Change Research Program, grew out of the recommendations of a National Academy of Sciences workshop in 1984. An ambitious goal was set to understand the controls on the concentrations and fluxes of carbon and associated nutrients in the ocean. A new field of ocean biogeochemistry emerged with an emphasis on quality measurements of carbon system parameters and interdisciplinary field studies of the biological, chemical and physical process which control the ocean carbon cycle. U.S. JGOFS, ended in 2005 with the conclusion of the Synthesis and Modeling Project (SMP). Data are available throughout the U.S. JGOFS web site at http://usjgofs.whoi.edu/ and from the U.S. JGOFS Data System at http://usjgofs.whoi.edu/jg/dir/jgofs/. Major named segments of the project are: Bermuda Atlantic Time Series (BATS) Study, Hawaii Ocean Time-series (HOT) Study, Equatorial Pacific Process Study, North Atlantic Bloom Experiment (1989), Arabian Sea Process Study, and the Southern Ocean Process Study.

  14. A Parallel Ocean Model With Adaptive Mesh Refinement Capability For Global Ocean Prediction

    SciTech Connect

    Herrnstein, Aaron R.

    2005-12-01

    An ocean model with adaptive mesh refinement (AMR) capability is presented for simulating ocean circulation on decade time scales. The model closely resembles the LLNL ocean general circulation model with some components incorporated from other well known ocean models when appropriate. Spatial components are discretized using finite differences on a staggered grid where tracer and pressure variables are defined at cell centers and velocities at cell vertices (B-grid). Horizontal motion is modeled explicitly with leapfrog and Euler forward-backward time integration, and vertical motion is modeled semi-implicitly. New AMR strategies are presented for horizontal refinement on a B-grid, leapfrog time integration, and time integration of coupled systems with unequal time steps. These AMR capabilities are added to the LLNL software package SAMRAI (Structured Adaptive Mesh Refinement Application Infrastructure) and validated with standard benchmark tests. The ocean model is built on top of the amended SAMRAI library. The resulting model has the capability to dynamically increase resolution in localized areas of the domain. Limited basin tests are conducted using various refinement criteria and produce convergence trends in the model solution as refinement is increased. Carbon sequestration simulations are performed on decade time scales in domains the size of the North Atlantic and the global ocean. A suggestion is given for refinement criteria in such simulations. AMR predicts maximum pH changes and increases in CO2 concentration near the injection sites that are virtually unattainable with a uniform high resolution due to extremely long run times. Fine scale details near the injection sites are achieved by AMR with shorter run times than the finest uniform resolution tested despite the need for enhanced parallel performance. The North Atlantic simulations show a reduction in passive tracer errors when AMR is applied instead of a uniform coarse resolution. No

  15. The timescales of global surface-ocean connectivity

    PubMed Central

    Jönsson, Bror F.; Watson, James R.

    2016-01-01

    Planktonic communities are shaped through a balance of local evolutionary adaptation and ecological succession driven in large part by migration. The timescales over which these processes operate are still largely unresolved. Here we use Lagrangian particle tracking and network theory to quantify the timescale over which surface currents connect different regions of the global ocean. We find that the fastest path between two patches—each randomly located anywhere in the surface ocean—is, on average, less than a decade. These results suggest that marine planktonic communities may keep pace with climate change—increasing temperatures, ocean acidification and changes in stratification over decadal timescales—through the advection of resilient types. PMID:27093522

  16. Signature of ocean warming in global fisheries catch.

    PubMed

    Cheung, William W L; Watson, Reg; Pauly, Daniel

    2013-05-16

    Marine fishes and invertebrates respond to ocean warming through distribution shifts, generally to higher latitudes and deeper waters. Consequently, fisheries should be affected by 'tropicalization' of catch (increasing dominance of warm-water species). However, a signature of such climate-change effects on global fisheries catch has so far not been detected. Here we report such an index, the mean temperature of the catch (MTC), that is calculated from the average inferred temperature preference of exploited species weighted by their annual catch. Our results show that, after accounting for the effects of fishing and large-scale oceanographic variability, global MTC increased at a rate of 0.19 degrees Celsius per decade between 1970 and 2006, and non-tropical MTC increased at a rate of 0.23 degrees Celsius per decade. In tropical areas, MTC increased initially because of the reduction in the proportion of subtropical species catches, but subsequently stabilized as scope for further tropicalization of communities became limited. Changes in MTC in 52 large marine ecosystems, covering the majority of the world's coastal and shelf areas, are significantly and positively related to regional changes in sea surface temperature. This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions.

  17. Effects of Drake Passage on a strongly eddying global ocean

    NASA Astrophysics Data System (ADS)

    Viebahn, Jan; von der Heydt, Anna S.; Dijkstra, Henk A.

    2015-04-01

    During the past 65 Million (Ma) years, Earth's climate has undergone a major change from warm 'greenhouse' to colder 'icehouse' conditions with extensive ice sheets in the polar regions of both hemispheres. The Eocene-Oligocene (~34 Ma) and Oligocene-Miocene (~23 Ma) boundaries reflect major transitions in Cenozoic global climate change. Proposed mechanisms of these transitions include reorganization of ocean circulation due to critical gateway opening/deepening, changes in atmospheric CO2-concentration, and feedback mechanisms related to land-ice formation. Drake Passage (DP) is an intensively studied gateway because it plays a central role in closing the transport pathways of heat and chemicals in the ocean. The climate response to a closed DP has been explored with a variety of general circulation models, however, all of these models employ low model-grid resolutions such that the effects of subgrid-scale fluctuations ('eddies') are parameterized. We present results of the first high-resolution (0.1° horizontally) realistic global ocean model simulation with a closed DP in which the eddy field is largely resolved. The simulation extends over more than 200 years such that the strong transient adjustment process is passed and a near-equilibrium ocean state is reached. The effects of DP are diagnosed by comparing with both an open DP high-resolution control simulation (of same length) and corresponding low-resolution simulations. By focussing on the heat/tracer transports we demonstrate that the results are twofold: Considering spatially integrated transports the overall response to a closed DP is well captured by low-resolution simulations. However, looking at the actual spatial distributions drastic differences appear between far-scattered high-resolution and laminar-uniform low-resolution fields. We conclude that sparse and highly localized tracer proxy observations have to be interpreted carefully with the help of high-resolution model simulations.

  18. The global land and ocean mean energy balance

    NASA Astrophysics Data System (ADS)

    Wild, Martin; Folini, Doris

    2016-04-01

    land, and 16 and 100 Wm-2 over oceans, for sensible and latent heat fluxes, respectively. Estimated uncertainties are on the order of 10 and 5 Wm-2 for most surface and TOA fluxes, respectively. Combining these surface budgets with satellite-determined TOA budgets (CERES-EBAF) results in an atmospheric solar absorption of 77 and 82 Wm-2 and a net atmospheric thermal emission of -165 and -190 Wm-2 over land and oceans, respectively. We further revisit the global mean energy balance by combining the area weighed land and ocean mean budgets. This study is published in: Wild, M., Folini, D., Hakuba, M., Schär, C., Seneviratne, S.I., Kato, S., Rutan, D., Ammann, C., Wood, E.F., and König-Langlo, G., 2015: The energy balance over land and oceans: An assessment based on direct observations and CMIP5 climate models. Clim. Dyn., Dyn., 44, 3393-3429, doi: 10.1007/s00382-014-2430-z.

  19. Trace Metals in the Oceans: Evolution, Biology and Global Change

    NASA Astrophysics Data System (ADS)

    de Baar, H.; La Roche, J.

    2003-04-01

    During evolution of prokaryotes and later on eukaryotes several metals became incorporated as essential factors in many biochemical functions in accordance with the abundance of these metals on the planet. The biological role of first row metals can be ranked Fe, Zn, Cu, Mn, Co, Ni. Second row metals Ag and Cd or third row metals like Hg and Pb appear to have no biological function, except possibly for Cd. Iron (Fe) being the fourth most abundant element of the planet has also played a role to temper the evolution of biogenic oxygen in the atmosphere and oceans. Yet eventually O2 has taken over the biosphere where now both atmosphere and ocean are strongly oxidizing. Inside every cell the primordial reducing conditions have remained however. Therefore enzyme systems based on metal couples Fe-Mn and Cu-Zn are required to protect the cell interior from damage by reactive oxygen species. The key role of metals in these and many other enzymes as well as in protein folding is one of the major vectors in biological diversity at both the molecular and the species level. Plankton ecosystems are governed by colimitation of several metals. Co-limitation of plankton growth is consistent also with observed interactions between metals. The supply of Fe to ocean waters is one of the major controls of plankton ecosystems and ocean element cycling (C, Si, N, P) over time scales ranging from weeks to the 100,000 year periodicity of glaciations. Understanding the role of metals in the oceans is crucial for understanding global change of past, present and future.

  20. Decoupling of iron and phosphate in the global ocean

    NASA Astrophysics Data System (ADS)

    Parekh, P.; Follows, M. J.; Boyle, E. A.

    2005-06-01

    We formulate a mechanistic model of the coupled oceanic iron and phosphorus cycles. The iron parameterization includes scavenging onto sinking particles, complexation with an organic ligand, and a prescribed aeolian source. Export production is limited by the availability of light, phosphate, and iron. We implement this biogeochemical scheme in a coarse resolution ocean general circulation model using scavenging rates and conditional stability constants guided by laboratory studies and a suite of box model sensitivity studies. The model is able to reproduce the broad regional patterns of iron and phosphorus. In particular, the high macronutrient concentrations of the Southern Ocean, tropical Pacific, and subarctic Pacific emerge from the explicit iron limitation of the model. In addition, the model also qualitatively reproduces the observed interbasin gradients of deep, dissolved iron with the lowest values in the Southern Ocean. The ubiquitous presence of significant amounts of free ligand is also explicitly captured. We define a tracer, Fe* which quantifies the degree to which a water mass is iron limited, relative to phosphorus. Surface waters in high-nutrient, low-chlorophyll regions have negative Fe* values, indicating Fe limitation. The extent of the decoupling of iron and phosphorus is determined by the availability and binding strength of the ligand relative to the scavenging by particulate. Global iron concentrations are sensitive to changes in scavenging rate and physical forcing. Decreasing the scavenging rate 40% results in ˜0.1 nM increase in dissolved iron in deep waters. Forcing the model with weaker wind stresses leads to a decrease in surface [PO4] and [Fe] in the Southern Ocean due to a reduction in the upwelling strength.

  1. Nonlinear Dependence of Global Warming Prediction on Ocean State

    NASA Astrophysics Data System (ADS)

    Liang, M.; Lin, L.; Tung, K. K.; Yung, Y. L.; Sun, S.

    2010-12-01

    Global temperature has increased by 0.8 C since the pre-industrial era, and is likely to increase further if greenhouse gas emission continues unchecked. Various mitigation efforts are being negotiated among nations to keep the increase under 2 C, beyond which the outcome is believed to be catastrophic. Such policy efforts are currently based on predictions by the state-of-the-art coupled atmosphere ocean models (AOGCM). Caution is advised for their use for the purpose of short-term (less than a century) climate prediction as the predicted warming and spatial patterns vary depending on the initial state of the ocean, even in an ensemble mean. The range of uncertainty in such predictions by Intergovernmental Panel on Climate Change (IPCC) models may be underreported when models were run with their oceans at various stages of adjustment with their atmospheres. By comparing a very long run (> 1000 years) of the coupled Goddard Institute for Space Studies (GISS) model with what was reported to IPCC Fourth Assessment Report (AR4), we show that the fully adjusted model transient climate sensitivity should be 30% higher for the same model, and the 2 C warming should occur sooner than previously predicted. Using model archives we further argue that this may be a common problem for the IPCC AR4 models, since few, if any, of the models has a fully adjusted ocean. For all models, multi-decadal climate predictions to 2050 are highly dependent on the initial ocean state (and so are unreliable). Such dependence cannot be removed simply by subtracting the climate drift from control runs.

  2. Ocean Model, Analysis and Prediction System version 3: operational global ocean forecasting

    NASA Astrophysics Data System (ADS)

    Brassington, Gary; Sandery, Paul; Sakov, Pavel; Freeman, Justin; Divakaran, Prasanth; Beckett, Duan

    2017-04-01

    The Ocean Model, Analysis and Prediction System version 3 (OceanMAPSv3) is a near-global (75S-75N; no sea-ice), uniform horizontal resolution (0.1°x0.1°), 51 vertical level ocean forecast system producing daily analyses and 7 day forecasts. This system was declared operational at the Bureau of Meteorology in April 2016 and subsequently upgraded to include ACCESS-G APS2 in June 2016 and finally ported to the Bureau's new supercomputer in Sep 2016. This system realises the original vision of the BLUElink projects (2003-2015) to provide global forecasts of the ocean geostrophic turbulence (eddies and fronts) in support of Naval operations as well as other national services. The analysis system has retained an ensemble-based optimal interpolation method with 144 stationary ensemble members derived from a multi-year hindcast. However, the BODAS code has been upgraded to a new code base ENKF-C. A new strategy for initialisation has been introduced leading to greater retention of analysis increments and reduced shock. The analysis cycle has been optimised for a 3-cycle system with 3 day observation windows retaining an advantage as a multi-cycle time-lagged ensemble. The sea surface temperature and sea surface height anomaly analysis errors in the Australian region are 0.34 degC and 6.2 cm respectively an improvement of 10% and 20% respectively over version 2. In addition, the RMSE of the 7 day forecast has lower error than the 1 day forecast from the previous system (version 2). International intercomparisons have shown that this system is comparable in performance with the two leading systems and is often the leading performer for surface temperature and upper ocean temperature. We present an overview of the system, the data assimilation and initialisation, demonstrate the performance and outline future directions.

  3. Estimates of Gelatinous Zooplankton Carbon Flux in the Global Oceans

    NASA Astrophysics Data System (ADS)

    Luo, J. Y.; Condon, R.; Cowen, R. K.

    2016-02-01

    Gelatinous zooplankton (GZ), which include the cnidarians, ctenophores, and pelagic tunicates, are a common feature of marine ecosystems worldwide, but their contribution to global biogeochemical fluxes has never been assessed. We constructed a carbon-cycle model with a single, annual time-step and resolved to a 5° spatial grid for the three major GZ groups in order to evaluate the GZ-mediated carbon fluxes and export to depth. Biomass inputs (totaling 0.149 Pg C) were based off of Lucas et al. (2014) and updated using the JeDI database (Condon et al. 2015). From the upper ocean, biomass export flux from cnidarians, ctenophores, and tunicates totaled 2.96 ± 2.82 Pg C y-1, though only 0.199 ± 0.023 Pg C y-1 of GZ carbon were transferred to upper trophic levels, roughly amounting to one-quarter of all mesozooplankton production flux. In contrast, GZ fluxes to DOC only comprised ca. 2% of labile DOC flux. Egestion flux from the upper ocean totaled 2.56 ± 3.35 Pg C y-1, with over 80% being fast-sinking tunicate fecal pellets. Due to fast sinking rates of carcasses and fecal pellets, 26% of all C export from the upper ocean reached the seafloor, such that GZ fecal matter is estimated to comprise between 20-30% of global POC surface export and 11-30% of POC seafloor deposition. Finally, results from sensitivity analyses showed no increase in cnidarian and ctenophore export fluxes with increased temperature and jelly biomass, though tunicate export fluxes showed some increase with both temperature and biomass. These results suggest that current estimates of global POC flux from the surface oceans, which range between 8.6 - 12.9 Pg C y-1, may be underestimated by as much as 20 - 25%, implying a definite need to incorporate GZ mediated flux in estimating the biological pump transfer efficiency. Our study represents the first effort to quantify the role of gelatinous zooplankton in the global marine carbon cycle.

  4. Impact of Parameterized Internal Wave Drag on the Semidiurnal Energy Balancein a Global Ocean Circulation Model

    DTIC Science & Technology

    2016-04-12

    Impact of Parameterized Internal Wave Drag on the Semidiurnal Energy Balance in a Global Ocean Circulation Model* MAARTENC. BUIJSMAN,1 JOSEPHK...of Southern Mississippi, Stennis Space Center, Mississippi #University of Michigan, Ann Arbor, Michigan @Center for Ocean -Atmospheric Prediction...parameterized linear internal wave drag on the semidiurnal barotropic and baroclinic energetics of a realistically forced, three-dimensional global ocean

  5. The Mercator-Ocean forecasting service: a 4D vision of the global ocean, serving the ocean services.

    NASA Astrophysics Data System (ADS)

    Hernandez, F.

    2006-12-01

    Mercator Ocean is a public consortium formed in Toulouse in early 2002 by the six major players in the French oceanography community: the space agency CNES, the scientific research centre CNRS, IFREMER (the institute of marine research and exploration), the development research institute IRD, the Meo France weather service, and SHOM (the French Navy's hydrography & oceanography department). In 1995, these same organizations gave themselves seven years to achieve a challenging objective: to conceive, develop and implement France's first operational oceanography system. The unique system would be capable of describing, analysing and predicting conditions at the ocean surface and subsurface in real time, anytime, anywhere in the world, even in the most inhospitable seas. That objective was met on 17 January 2001 with the release of the first Mercator ocean bulletin, providing a two-week forecast for the entire North Atlantic. More than three thousands new forecast charts are now added to the MERCATOR bulletin every week. Building on these successes, a dedicated operational oceanography team, Mercator Ocean, was set up in 2002. Mercator-Ocean's mission is to deliver incremental improvements in the service provided by this new operational oceanography capability by increasing the resolution and the geographic coverage of the models used. The current high-resolution model offers a 6 km grid resolution, and the first models offering global ocean coverage has been implemented early 2004. A ¼° model is operated since October 2005. The services offered by Mercator-Ocean consist in a real-time general description of the physical state of the ocean (3D currents, temperature, salinity ). This is exactly in line with the so called Marine Core Service initiative developed by the operational oceanography community within the programs funded by the European Commission and the European Space Agency (Marcoast, Mersea, BOSS4GMES projects ). The downstream activities are now in

  6. Global Terrestrial Water Storage Changes and Connections to ENSO Events

    NASA Astrophysics Data System (ADS)

    Ni, Shengnan; Chen, Jianli; Wilson, Clark R.; Li, Jin; Hu, Xiaogong; Fu, Rong

    2017-07-01

    Improved data quality of extended record of the Gravity Recovery and Climate Experiment (GRACE) satellite gravity solutions enables better understanding of terrestrial water storage (TWS) variations. Connections of TWS and climate change are critical to investigate regional and global water cycles. In this study, we provide a comprehensive analysis of global connections between interannual TWS changes and El Niño Southern Oscillation (ENSO) events, using multiple sources of data, including GRACE measurements, land surface model (LSM) predictions and precipitation observations. We use cross-correlation and coherence spectrum analysis to examine global connections between interannual TWS changes and the Niño 3.4 index, and select four river basins (Amazon, Orinoco, Colorado, and Lena) for more detailed analysis. The results indicate that interannual TWS changes are strongly correlated with ENSO over much of the globe, with maximum cross-correlation coefficients up to 0.70, well above the 95% significance level ( 0.29) derived by the Monte Carlo experiments. The strongest correlations are found in tropical and subtropical regions, especially in the Amazon, Orinoco, and La Plata basins. While both GRACE and LSM TWS estimates show reasonably good correlations with ENSO and generally consistent spatial correlation patterns, notably higher correlations are found between GRACE TWS and ENSO. The existence of significant correlations in middle-high latitudes shows the large-scale impact of ENSO on the global water cycle.

  7. Global ocean circulation and equator-pole heat transport as a function of ocean GCM resolution

    SciTech Connect

    Covey, C.

    1994-06-01

    To determine whether resolution of smaller scales is necessary to simulate large-scale ocean climate correctly, I examine results from a global ocean GCM run with horizontal grid spacings spanning a range from coarse resolutions traditionally used in climate modeling to nearly the highest resolution attained with today`s computers. The experiments include four cases employing 4{degrees}, 2{degrees}, 1{degrees} and 1/2{degrees} spacing in latitude and longitude, which were run with minimal differences among them, i.e., in a controlled experiment. Two additional cases-1/2{degrees} spacing with a more scale-selective sub-gridscale mixing of heat and momentum, and approximate 1/4{degrees} spacing-are also included. The 1/4{degrees} run resolves most of the observed mesoscale eddy energy in the ocean. Several artificial constraints on the model tend to minimize differences among the different resolution cases. Nevertheless, for quantities of interest to global climate studies,the simulations show significant changes as resolution increases.

  8. Multidecadal Variability of Global Ocean and its Relationship to Recent Global Warming Slowdown

    NASA Astrophysics Data System (ADS)

    Chen, X.; Tung, K. K.

    2016-02-01

    When the global-mean surface temperature did not warm as expected in the presence of ever increasing atmospheric concentration of greenhouse gases that enhance the long-wave radiation to space, there can be only two possible reasons, both involving the energy budget of the earth: (1) the radiative heating was not appreciably reaching the surface-most of it presumably was reflected back to space by, for example, increasing aerosols from volcanoes and anthropogenic pollution, or (2) that the heating was reaching the surface and below, but was sequestered in the oceans. From an energy perspective, while more heat was moved into deeper oceans in the 21st century, surface warming slowed. The main sites of ocean heat uptake below 300m are found in the Atlantic and the Southern Oceans, and not in the Pacific. The longer record of intermediate layer ocean measurements in the North Atlantic suggests that the interval between ocean regime shifts is about three decades, is density/salinity initiated, and involves a negative feedback that produces the acceleration and deceleration regimes of the Atlantic Meridional Overturning Circulation on the multidecadal time scales.

  9. Accuracy Assessment of Recent Global Ocean Tide Models around Antarctica

    NASA Astrophysics Data System (ADS)

    Lei, J.; Li, F.; Zhang, S.; Ke, H.; Zhang, Q.; Li, W.

    2017-09-01

    Due to the coverage limitation of T/P-series altimeters, the lack of bathymetric data under large ice shelves, and the inaccurate definitions of coastlines and grounding lines, the accuracy of ocean tide models around Antarctica is poorer than those in deep oceans. Using tidal measurements from tide gauges, gravimetric data and GPS records, the accuracy of seven state-of-the-art global ocean tide models (DTU10, EOT11a, GOT4.8, FES2012, FES2014, HAMTIDE12, TPXO8) is assessed, as well as the most widely-used conventional model FES2004. Four regions (Antarctic Peninsula region, Amery ice shelf region, Filchner-Ronne ice shelf region and Ross ice shelf region) are separately reported. The standard deviations of eight main constituents between the selected models are large in polar regions, especially under the big ice shelves, suggesting that the uncertainty in these regions remain large. Comparisons with in situ tidal measurements show that the most accurate model is TPXO8, and all models show worst performance in Weddell sea and Filchner-Ronne ice shelf regions. The accuracy of tidal predictions around Antarctica is gradually improving.

  10. Global ocean particulate organic carbon flux merged with satellite parameters

    NASA Astrophysics Data System (ADS)

    Mouw, Colleen B.; Barnett, Audrey; McKinley, Galen A.; Gloege, Lucas; Pilcher, Darren

    2016-10-01

    Particulate organic carbon (POC) flux estimated from POC concentration observations from sediment traps and 234Th are compiled across the global ocean. The compilation includes six time series locations: CARIACO, K2, OSP, BATS, OFP, and HOT. Efficiency of the biological pump of carbon to the deep ocean depends largely on biologically mediated export of carbon from the surface ocean and its remineralization with depth; thus biologically related parameters able to be estimated from satellite observations were merged at the POC observation sites. Satellite parameters include net primary production, percent microplankton, sea surface temperature, photosynthetically active radiation, diffuse attenuation coefficient at 490 nm, euphotic zone depth, and climatological mixed layer depth. Of the observations across the globe, 85 % are concentrated in the Northern Hemisphere with 44 % of the data record overlapping the satellite record. Time series sites accounted for 36 % of the data, while 71 % of the data are measured at ≥ 500 m with the most common deployment depths between 1000 and 1500 m. This data set is valuable for investigations of CO2 drawdown, carbon export, remineralization, and sequestration. The compiled data can be freely accessed at doi:10.1594/PANGAEA.855600.

  11. Co-location of air capture, sub-ocean CO2 storage and energy production on the Kerguelen plateau

    NASA Astrophysics Data System (ADS)

    Goldberg, D.; Han, P.; Lackner, K.; Wang, T.

    2011-12-01

    How can carbon capture and storage activities be sustained from an energy perspective while keeping the entire activity out of sight and away from material risk and social refrain near populated areas? In light of reducing the atmospheric CO2 level to mitigate its effect on climate change, the combination of new air-capture technologies and large offshore storage reservoirs, supplemented by carbon neutral renewable energy, could address both of these engineering and public policy concerns. Because CO2 mixes rapidly in the atmosphere, air capture scrubbers could be located anywhere in the world. Although the power requirements for this technology may reduce net efficiencies, the local availability of carbon-neutral renewable energy for this purpose would eliminate some net energy loss. Certain locations where wind speeds are high and steady, such as those observed at high latitude and across the open ocean, appeal as carbon-neutral energy sources in close proximity to immense and secure reservoirs for geological sequestration of captured CO2. In particular, sub-ocean basalt flows are vast and carry minimal risks of leakage and damages compared to on-land sites. Such implementation of a localized renewable energy source coupled with carbon capture and storage infrastructure could result in a global impact of lowered CO2 levels. We consider an extreme location on the Kerguelen plateau in the southern Indian Ocean, where high wind speeds and basalt storage reservoirs are both plentiful. Though endowed with these advantages, this mid-ocean location incurs clear material and economic challenges due to its remoteness and technological challenges for CO2 capture due to constant high humidity. We study the wind energy-air capture power balance and consider related factors in the feasibility of this location for carbon capture and storage. Other remote oceanic sites where steady winds blow and near large geological reservoirs may be viable as well, although all would require

  12. Global abundance of planktonic heterotrophic protists in the deep ocean

    PubMed Central

    Pernice, Massimo C; Forn, Irene; Gomes, Ana; Lara, Elena; Alonso-Sáez, Laura; Arrieta, Jesus M; del Carmen Garcia, Francisca; Hernando-Morales, Victor; MacKenzie, Roy; Mestre, Mireia; Sintes, Eva; Teira, Eva; Valencia, Joaquin; Varela, Marta M; Vaqué, Dolors; Duarte, Carlos M; Gasol, Josep M; Massana, Ramon

    2015-01-01

    The dark ocean is one of the largest biomes on Earth, with critical roles in organic matter remineralization and global carbon sequestration. Despite its recognized importance, little is known about some key microbial players, such as the community of heterotrophic protists (HP), which are likely the main consumers of prokaryotic biomass. To investigate this microbial component at a global scale, we determined their abundance and biomass in deepwater column samples from the Malaspina 2010 circumnavigation using a combination of epifluorescence microscopy and flow cytometry. HP were ubiquitously found at all depths investigated down to 4000 m. HP abundances decreased with depth, from an average of 72±19 cells ml−1 in mesopelagic waters down to 11±1 cells ml−1 in bathypelagic waters, whereas their total biomass decreased from 280±46 to 50±14 pg C ml−1. The parameters that better explained the variance of HP abundance were depth and prokaryote abundance, and to lesser extent oxygen concentration. The generally good correlation with prokaryotic abundance suggested active grazing of HP on prokaryotes. On a finer scale, the prokaryote:HP abundance ratio varied at a regional scale, and sites with the highest ratios exhibited a larger contribution of fungi molecular signal. Our study is a step forward towards determining the relationship between HP and their environment, unveiling their importance as players in the dark ocean's microbial food web. PMID:25290506

  13. Global abundance of planktonic heterotrophic protists in the deep ocean.

    PubMed

    Pernice, Massimo C; Forn, Irene; Gomes, Ana; Lara, Elena; Alonso-Sáez, Laura; Arrieta, Jesus M; del Carmen Garcia, Francisca; Hernando-Morales, Victor; MacKenzie, Roy; Mestre, Mireia; Sintes, Eva; Teira, Eva; Valencia, Joaquin; Varela, Marta M; Vaqué, Dolors; Duarte, Carlos M; Gasol, Josep M; Massana, Ramon

    2015-03-01

    The dark ocean is one of the largest biomes on Earth, with critical roles in organic matter remineralization and global carbon sequestration. Despite its recognized importance, little is known about some key microbial players, such as the community of heterotrophic protists (HP), which are likely the main consumers of prokaryotic biomass. To investigate this microbial component at a global scale, we determined their abundance and biomass in deepwater column samples from the Malaspina 2010 circumnavigation using a combination of epifluorescence microscopy and flow cytometry. HP were ubiquitously found at all depths investigated down to 4000 m. HP abundances decreased with depth, from an average of 72±19 cells ml(-1) in mesopelagic waters down to 11±1 cells ml(-1) in bathypelagic waters, whereas their total biomass decreased from 280±46 to 50±14 pg C ml(-1). The parameters that better explained the variance of HP abundance were depth and prokaryote abundance, and to lesser extent oxygen concentration. The generally good correlation with prokaryotic abundance suggested active grazing of HP on prokaryotes. On a finer scale, the prokaryote:HP abundance ratio varied at a regional scale, and sites with the highest ratios exhibited a larger contribution of fungi molecular signal. Our study is a step forward towards determining the relationship between HP and their environment, unveiling their importance as players in the dark ocean's microbial food web.

  14. Phytoplankton size impact on export flux in the global ocean

    NASA Astrophysics Data System (ADS)

    Mouw, Colleen B.; Barnett, Audrey; McKinley, Galen A.; Gloege, Lucas; Pilcher, Darren

    2016-10-01

    Efficiency of the biological pump of carbon to the deep ocean depends largely on biologically mediated export of carbon from the surface ocean and its remineralization with depth. Global satellite studies have primarily focused on chlorophyll concentration and net primary production (NPP) to understand the role of phytoplankton in these processes. Recent satellite retrievals of phytoplankton composition now allow for the size of phytoplankton cells to be considered. Here we improve understanding of phytoplankton size structure impacts on particle export, remineralization, and transfer. A global compilation of particulate organic carbon (POC) flux estimated from sediment traps and 234Th are utilized. Annual climatologies of NPP, percent microplankton, and POC flux at four time series locations and within biogeochemical provinces are constructed. Parameters that characterize POC flux versus depth (export flux ratio, labile fraction, and remineralization length scale) are fit for time series locations, biogeochemical provinces, and times of the year dominated by small and large phytoplankton cells where phytoplankton cell size show enough dynamic range over the annual cycle. Considering all data together, our findings support the idea of high export flux but low transfer efficiency in productive regions and vice versa for oligotrophic regions. However, when parsing by dominant size class, we find periods dominated by small cells to have both greater export flux efficiency and lower transfer efficiency than periods when large cells comprise a greater proportion of the phytoplankton community.

  15. Flavours of Baroclinic Instability in the Global Ocean

    NASA Astrophysics Data System (ADS)

    Keating, S. R.; Smith, K. S.

    2016-02-01

    The transfer of energy from the global ocean circulation to mesoscale eddies is primarily mediated by baroclinic instability, which releases the superabundant available potential energy stored in sloping isopycnals by basin-scale wind and buoyancy forcing. However, the details of the local shear and stratification can give rise to qualitatively distinct flavours of baroclinic instability. In particular, the presence of outcropping isopycnals (or, equivalent, a thermal wind shear at the upper surface) can have a strong impact on the necessary conditions for baroclinic instability and the resulting nonlinear cascade to submesoscales. In this article, a simple framework is described for categorizing baroclinic instability in terms of two non-dimensional parameters, the Charney-Green number and the Phillips supercriticality. We analyze the influence of a non-zonal mean flow on growth rates and the baroclinic conversion of available potential energy to eddy kinetic energy. Finally, hydrographic profiles are used to form a global atlas of baroclinic instability in the ocean, and regional patterns are discussed.

  16. Madden Julian Oscillation impacts on global ocean surface waves

    NASA Astrophysics Data System (ADS)

    Marshall, Andrew G.; Hendon, Harry H.; Durrant, Tom H.; Hemer, Mark A.

    2015-12-01

    We assess the impact of the tropical Madden Julian Oscillation (MJO) on global ocean wind waves using 30 years of wave data from a wave model hindcast that is forced with high resolution surface winds from the NCEP-CFSR reanalysis. We concentrate on the boreal winter season when the MJO has its greatest amplitude and is potentially a source of predictable wave impacts at intra-seasonal lead times. Statistically significant anomalies in significant wave height (Hs), peak wave period (Tp) and zonal wave energy flux (CgE) are found to covary with the intra-seasonal variation of surface zonal wind induced by the MJO as it traverses eastward from the western tropical Indian Ocean to the eastern tropical Pacific. Tp varies generally out of phase with Hs over the life cycle of the MJO, indicating that these MJO-wave anomalies are locally wind-generated rather than remotely generated by ocean swell. Pronounced Hs anomalies develop on the northwest shelf of Australia, where the MJO is known to influence sea level and surface temperatures, and in the western Caribbean Sea and Guatemalan-Panama Seas with enhanced wave anomalies apparent in the vicinity of the Tehuantepec and Papagayo gaps. Significant wave anomalies are also detected in the North Pacific and North Atlantic oceans in connection with the MJO teleconnection to the extratropics via atmospheric wave propagation. The impact in the north Atlantic stems from induction of the high phase of the North Atlantic Oscillation (NAO) about 1 week after MJO convection traverses the Indian Ocean, and the low phase of the NAO about one week after suppressed convection traverses the Indian Ocean. Strong positive Hs anomalies maximize on the Northern European coast in the positive NAO phase and vice versa for the negative NAO phase. The MJO also influences the occurrence of daily low (below the 5th percentile) and high (above the 95th percentile) wave conditions across the tropics and in the North Pacific and North Atlantic

  17. Global Estimate of Seasonality in Scales of Oceanic Turbulence

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Abernathey, R. P.

    2016-02-01

    Wavenumber spectral analysis is a powerful method for characterizing the properties of ocean turbulence. Here we calculate seasonally and regionally resolved wavenumber power spectra of sea-surface temperature (SST), sea-surface height (SSH), and surface eddy kinetic energy (EKE) from the high resolution ocean component of a CESM global climate model. Until now there has not been a comprehensive analysis of ocean mesoscale turbulence in this new category of model. Furthermore, this study provides a test bed for future work on infrared satellite observations. The ocean component model (POP) has 0.1° degree resolution, mesoscale resolving at most latitudes. We have found seasonality in the spectra, which indicates the possibility of different turbulent schemes for each season. Although the spatial resolution of the model is not considered submesoscale resolving, we see that the seasonality originates in the submesoscale range (below 50km) in the power level of the spectra. On the other hand, it is difficult to extract physical meanings from the actual values of spectral slopes since the slopes depend on the wavelength range we fit the spectra due to numerical viscosity. Thus, we propose the possibility of mixed-layer instability (e.g. Callies et al. (2014)) playing an important role in the seasonality of submeso/mesoscale turbulence, and power levels are a more robust criteria in detecting seasonality than spectral slopes. We also compare the spectral analysis with structure function analysis. The strength of structure functions is that they can characterize scaling properties of turbulence even when the data has gaps or missing data as in infrared satellite observations of SST.

  18. Global Impact of Land Use on Soil Carbon Storage

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Hengl, T.; Fiske, G. J.; Cheney, E.

    2016-12-01

    Land use and land cover change has resulted in substantial losses of carbon from soils globally. This historic loss in soil organic carbon now represents a significant climate mitigation opportunity. Current estimates of the potential soil organic carbon (SOC) sink strength generally come from simplistic bookkeeping calculations that have been disaggregated to at best the continental scale. Others have taken a modeling approach whereby agroecosystem models have been run using alternative management practices to estimate SOC sequestration potential. A third approach which is adopted here is to use a data-driven spatial modeling approach whereby measured SOC stocks from minimally distrubed regions are projected across the highly managed regions of the world. The International Soil Reference and Information Center (www.isric.org) curates the largest repository of spatially explicit soil data which now includes data from over 150,000 soil profiles globally. From this dataset, we have masked out data from profiles collected from used parts of the globe. Then SOC stocks were related to factors which are known to control SOC storage using machine learning algorithms. Spatially continuous data layers included climate, topography, lithology and potential vegetation class. The trained machine learning algorithms were then used to project potential SOC stocks across the entire global land surface at a resolution of 1 km. In addition to an assessment of model performance in the development stage, an independent test set of over 400 paired-plot (native v. agricultural) measurements of SOC stocks within major agricultural regions was collected to help validate model output. Land area with the largest carbon debit and thus the greatest potential of SOC storage was revealed by comparison of this potential SOC map with a map of actual SOC values (SoilGrids250m) that was produced using a consistent spatial modeling approach.

  19. Global and regional ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario

    NASA Astrophysics Data System (ADS)

    Vichi, Marcello; Manzini, Elisa; Fogli, Pier Giuseppe; Alessandri, Andrea; Patara, Lavinia; Scoccimarro, Enrico; Masina, Simona; Navarra, Antonio

    2011-11-01

    Under future scenarios of business-as-usual emissions, the ocean storage of anthropogenic carbon is anticipated to decrease because of ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the oceanic 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 ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model 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 ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model 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 model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic oceans is projected to be halved with respect to the current climate 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

  20. Ocean Circulation and Mixing: New Insights From the Global Distribution of 3He

    NASA Astrophysics Data System (ADS)

    Schlosser, P.; Newton, R.; Winckler, G.

    2007-05-01

    Since the discovery of mantle 3He in the ocean in the 1960's by Clarke and others this isotope has been used in numerous studies of ocean circulation and mixing. Recently, a global helium isotope data set has been collected during the World Ocean Circulation Experiment (WOCE). We combined the WOCE helium isotope data with similar, but smaller, data sets from previous global and regional studies such as GEOCSECS or TTO to study features of the global ocean circulation, as well as ventilation and mixing. In this contribution we describe the global data set and discuss the first results obtained on global ocean ventilation and deep ocean mixing. A simple model is used to estimate vertical turbulent exchange coefficients for the deep ocean in the South Pacific and the results are compared to mixing coefficients obtained from fine structure measurements and tracer release experiments.

  1. Design and analysis of a global sub-mesoscale and tidal dynamics admitting virtual ocean.

    NASA Astrophysics Data System (ADS)

    Menemenlis, D.; Hill, C. N.

    2016-02-01

    We will describe the techniques used to realize a global kilometerscale ocean model configuration that includes representation of sea-ice and tidal excitation, and spans scales from planetary gyres to internal tides. A simulation using this model configuration provides a virtual ocean that admits some sub-mesoscale dynamics and tidal energetics not normally represented in global calculations. This extends simulated ocean behavior beyond broadly quasi-geostrophic flows and provides a preliminary example of a next generation computational approach to explicitly probing the interactions between instabilities that are usually parameterized and dominant energetic scales in the ocean. From previous process studies we have ascertained that this can lead to a qualitative improvement in the realism of many significant processes including geostrophic eddy dynamics, shelf-break exchange and topographic mixing. Computationally we exploit high-degrees of parallelism in both numerical evaluation and in recording model state to persistent disk storage. Together this allows us to compute and record a full three-dimensional model trajectory at hourly frequency for a timeperiod of 5 months with less than 9 million core hours of parallel computer time, using the present generation NASA Ames Research Center facilities. We have used this capability to create a 5 month trajectory archive, sampled at high spatial and temporal frequency for an ocean configuration that is initialized from a realistic data-assimilated state and driven with reanalysis surface forcing from ECMWF. The resulting database of model state provides a novel virtual laboratory for exploring coupling across scales in the ocean, and for testing ideas on the relationship between small scale fluxes and large scale state. The computation is complemented by counterpart computations that are coarsened two and four times respectively. In this presentation we will review the computational and numerical technologies employed

  2. Designing Scatterometer Constellations for Sampling Global Ocean Vector Winds

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Chelton, D. B.; Stoffelen, A.; Schlax, M.

    2012-12-01

    The rapid temporal variations in ocean vector winds make it impossible to obtain synoptic global snapshots of winds and wind stress from a single spaceborne sensor. Even when multiple sensors are present, the peculiarities of the resulting space-time sampling pattern require that significant smoothing in space and time be performed to limit spatially and temporally inhomogeneous error characteristics in the merged data. Based on the collected common experience in its member states, the World Meteorological Organization collects requirements for spatio-temporal sampling in meteorological applications such as global and regional Numerical Weather Prediction, nowcasting, and climate. An additional concern, when constructing data sets from sun-synchronous missions, is that undersampling of diurnal and sub-diurnal variability may result in aliasing of the climate data record. Indeed, examination of climatologies constructed from different satellite missions, such as NASA's QuikSCAT and EUMETSAT's ASCAT scatterometers, show systematic differences that cannot be explained as being due solely to unresolved incoherent diurnal and sub-diurnal variability. Some of these differences, especially in the tropics, are probably explained by systematic diurnal and sub-diurnal variations. Other differences may be due to the difficulty of cross-calibrating sun-synchronous satellites with different local times. Forthcoming satellite missions may offer the possibility of overcoming or mitigating the space-time sampling and calibration challenges using multiple coordinated platforms. In the next decade, there is an expectation that ocean vector winds will be measured simultaneously by multiple satellites from the European community, India, China, and the United States. The coordination and suitable merging of the data from these satellites to produce a climate data record will be a challenge to the ocean vector winds community. In this presentation, we use climatologies constructed from

  3. Assimilation of SeaWiFS Ocean Chlorophyll Data into a Three-Dimensional Global Ocean Model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.

    2005-01-01

    Assimilation of satellite ocean color data is a relatively new phenomenon in ocean sciences. However, with routine observations from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), launched in late 1997, and now with new data from the Moderate Resolution Imaging Spectroradometer (MODIS) Aqua, there is increasing interest in ocean color data assimilation. Here SeaWiFS chlorophyll data were assimilated with an established thre-dimentional global ocean model. The assimilation improved estimates of hlorophyll and primary production relative to a free-run (no assimilation) model. This represents the first attempt at ocean color data assimilation using NASA satellites in a global model. The results suggest the potential of assimilation of satellite ocean chlorophyll data for improving models.

  4. Groundwater storage inferred from earthquake activities around East Asia and West Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Shih, David Ching-Fang

    2017-01-01

    Groundwater is a necessary and indispensable resource in the gradual depletion of the amount in the world. Groundwater storage is an important indicator to evaluate the capability of volume of water can be released from the aquifer. This research highlights a new assessment to infer the storage of aquifer using earthquakes activated around East Asia and the ring of fire at West Pacific Ocean. Ten significant seismic events are used to evaluate the groundwater storage at an observation station. By analyzing the spectra of groundwater level and seismogram, it is evident that the period varied in 7-25 s of Rayleigh waves significantly dominate propagation from the epicenter of earthquakes to the observation station. The storage coefficient is then shown in the order of 10-4-10-3. The major innovation of this study suggests that to concretely deduce the groundwater storage by earthquake activity has become feasible.

  5. Global CO2 storage potential of self-sealing marine sedimentary strata

    NASA Astrophysics Data System (ADS)

    Eccles, Jordan K.; Pratson, Lincoln

    2012-10-01

    One potential way to geologically sequester captured CO2 emissions is to inject them below the seafloor into marine sedimentary strata where pressures and temperatures would trap the CO2 through “self-sealing” gravitational and hydrate-formation mechanisms. Here we map out the worldwide distribution and thicknesses of such self-sealing strata using a comprehensive, global dataset of deep-sea sediment cores in combination with digital grids of ocean floor heat flow, bathymetry, and sediment thickness. Based on our mapping, we estimate that the total bulk sediment volume of self-sealing strata is 63 million cubic kilometers, 0.8-1.4 km3 (or ˜1.3-2.7%) of which are sands with intrinsic permeability suitable for storing CO2. This is enough storage capacity to hold between 1,260-28,500 gigatonnes of CO2, or about 40-1,000 y of total global CO2 emissions. However, the storage capacity is unevenly distributed where it lies within the Exclusive Economic Zones (EEZ) of the world's largest CO2 emitting economies. The United States and India respectively release 16% and 62% of their annual CO2 emissions (or 1 Bt/y and 800 Mt/y) within 500 km of self-sealing sands located in their EEZs, while only 6% of the annual emissions from China and the European Union (or 330 Mt/y and 250 Mt/y, respectively) occur within this distance.

  6. Modeling selective pressures on phytoplankton in the global ocean.

    PubMed

    Bragg, Jason G; Dutkiewicz, Stephanie; Jahn, Oliver; Follows, Michael J; Chisholm, Sallie W

    2010-03-10

    Our view of marine microbes is transforming, as culture-independent methods facilitate rapid characterization of microbial diversity. It is difficult to assimilate this information into our understanding of marine microbe ecology and evolution, because their distributions, traits, and genomes are shaped by forces that are complex and dynamic. Here we incorporate diverse forces--physical, biogeochemical, ecological, and mutational--into a global ocean model to study selective pressures on a simple trait in a widely distributed lineage of picophytoplankton: the nitrogen use abilities of Synechococcus and Prochlorococcus cyanobacteria. Some Prochlorococcus ecotypes have lost the ability to use nitrate, whereas their close relatives, marine Synechococcus, typically retain it. We impose mutations for the loss of nitrogen use abilities in modeled picophytoplankton, and ask: in which parts of the ocean are mutants most disadvantaged by losing the ability to use nitrate, and in which parts are they least disadvantaged? Our model predicts that this selective disadvantage is smallest for picophytoplankton that live in tropical regions where Prochlorococcus are abundant in the real ocean. Conversely, the selective disadvantage of losing the ability to use nitrate is larger for modeled picophytoplankton that live at higher latitudes, where Synechococcus are abundant. In regions where we expect Prochlorococcus and Synechococcus populations to cycle seasonally in the real ocean, we find that model ecotypes with seasonal population dynamics similar to Prochlorococcus are less disadvantaged by losing the ability to use nitrate than model ecotypes with seasonal population dynamics similar to Synechococcus. The model predictions for the selective advantage associated with nitrate use are broadly consistent with the distribution of this ability among marine picocyanobacteria, and at finer scales, can provide insights into interactions between temporally varying ocean processes and

  7. Does Ocean Color Data Assimilation Improve Estimates of Global Ocean Inorganic Carbon?

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2012-01-01

    Ocean color data assimilation has been shown to dramatically improve chlorophyll abundances and distributions globally and regionally in the oceans. Chlorophyll is a proxy for phytoplankton biomass (which is explicitly defined in a model), and is related to the inorganic carbon cycle through the interactions of the organic carbon (particulate and dissolved) and through primary production where inorganic carbon is directly taken out of the system. Does ocean color data assimilation, whose effects on estimates of chlorophyll are demonstrable, trickle through the simulated ocean carbon system to produce improved estimates of inorganic carbon? Our emphasis here is dissolved inorganic carbon, pC02, and the air-sea flux. We use a sequential data assimilation method that assimilates chlorophyll directly and indirectly changes nutrient concentrations in a multi-variate approach. The results are decidedly mixed. Dissolved organic carbon estimates from the assimilation model are not meaningfully different from free-run, or unassimilated results, and comparisons with in situ data are similar. pC02 estimates are generally worse after data assimilation, with global estimates diverging 6.4% from in situ data, while free-run estimates are only 4.7% higher. Basin correlations are, however, slightly improved: r increase from 0.78 to 0.79, and slope closer to unity at 0.94 compared to 0.86. In contrast, air-sea flux of C02 is noticeably improved after data assimilation. Global differences decline from -0.635 mol/m2/y (stronger model sink from the atmosphere) to -0.202 mol/m2/y. Basin correlations are slightly improved from r=O.77 to r=0.78, with slope closer to unity (from 0.93 to 0.99). The Equatorial Atlantic appears as a slight sink in the free-run, but is correctly represented as a moderate source in the assimilation model. However, the assimilation model shows the Antarctic to be a source, rather than a modest sink and the North Indian basin is represented incorrectly as a sink

  8. Rapid global ocean-atmosphere response to Southern Ocean freshening during the last glacial.

    PubMed

    Turney, Chris S M; Jones, Richard T; Phipps, Steven J; Thomas, Zoë; Hogg, Alan; Kershaw, A Peter; Fogwill, Christopher J; Palmer, Jonathan; Bronk Ramsey, Christopher; Adolphi, Florian; Muscheler, Raimund; Hughen, Konrad A; Staff, Richard A; Grosvenor, Mark; Golledge, Nicholas R; Rasmussen, Sune Olander; Hutchinson, David K; Haberle, Simon; Lorrey, Andrew; Boswijk, Gretel; Cooper, Alan

    2017-09-12

    Contrasting Greenland and Antarctic temperatures during the last glacial period (115,000 to 11,650 years ago) are thought to have been driven by imbalances in the rates of formation of North Atlantic and Antarctic Deep Water (the 'bipolar seesaw'). Here we exploit a bidecadally resolved (14)C data set obtained from New Zealand kauri (Agathis australis) to undertake high-precision alignment of key climate data sets spanning iceberg-rafted debris event Heinrich 3 and Greenland Interstadial (GI) 5.1 in the North Atlantic (~30,400 to 28,400 years ago). We observe no divergence between the kauri and Atlantic marine sediment (14)C data sets, implying limited changes in deep water formation. However, a Southern Ocean (Atlantic-sector) iceberg rafted debris event appears to have occurred synchronously with GI-5.1 warming and decreased precipitation over the western equatorial Pacific and Atlantic. An ensemble of transient meltwater simulations shows that Antarctic-sourced salinity anomalies can generate climate changes that are propagated globally via an atmospheric Rossby wave train.A challenge for testing mechanisms of past climate change is the precise correlation of palaeoclimate records. Here, through climate modelling and the alignment of terrestrial, ice and marine (14)C and (10)Be records, the authors show that Southern Ocean freshwater hosing can trigger global change.

  9. Role of the Polar Oceans in Global Climate

    NASA Technical Reports Server (NTRS)

    Rothrock, D. A.

    2003-01-01

    The project focused on ice-ocean model development and in particular on the assimilation of ice motion data and ice concentration data into both regional and global models. Many of the resulting publications below deal with improvements made in the physics treated by the model and the procedures for assimilating data. Several papers examine how the ability of the model to simulate the past behavior of the ice cover, especially to represent the ice thickness and ice deformation, is improved by data assimilation. A second aspect of the work involved interpretation of modeled behavior. Resulting papers treat the decline of arctic ice thickness over the last thirty years, and how that decline was caused by a slight warming of the near-surface atmosphere, and also how large variation in ice thickness are due to changes in wind patterns associated with a well- known oscillation of the atmospheric circulation. The research resulted in over 20 published papers on these topics.

  10. Assimilating ocean tide determined data into global tidal models

    NASA Astrophysics Data System (ADS)

    Zahel, W.

    1995-01-01

    A data assimilation procedure, which has successfully been applied to fictive and realistic scenarios, is applied to a 1 °-model making use of an effective iterative method for the solution of the minimization problem. Two sets of ocean tide determined data are used for the purpose of assimilation, the more extensive one mainly comprising pelagic together with some coastal sea surface elevation data, and the other one consisting of loading gravity data. The computed O1 and M2 global tidal oscillation systems, namely the fields of tidal elevation and loading gravity, are compared with numerous additional pelagic and coastal elevation data and with a selected number of proper gravity data, respectively. The assimilation of the two sets of data leads to an enormous reduction of the errors of the model results in all oceans. Assimilating this altogether still restricted number of data, allows studying the generation of realistic tidal oscillation phenomena by individual data and comparing these data effects with those having been obtained by previous data assimilation experiments using a model with coarser grid spacing. The field of dynamical residuals resulting from data assimilation reflects the far reaching influence of the data, and it is shown that the spatially integrated work done by the residuals contributes to the in all reduced rate of dissipation in the tidal power balance.

  11. Effects of Drake Passage on a strongly eddying global ocean

    NASA Astrophysics Data System (ADS)

    Viebahn, Jan P.; Heydt, Anna S.; Le Bars, Dewi; Dijkstra, Henk A.

    2016-05-01

    The climate impact of ocean gateway openings during the Eocene-Oligocene transition is still under debate. Previous model studies employed grid resolutions at which the impact of mesoscale eddies has to be parameterized. We present results of a state-of-the-art eddy-resolving global ocean model with a closed Drake Passage and compare with results of the same model at noneddying resolution. An analysis of the pathways of heat by decomposing the meridional heat transport into eddy, horizontal, and overturning circulation components indicates that the model behavior on the large scale is qualitatively similar at both resolutions. Closing Drake Passage induces (i) sea surface warming around Antarctica due to equatorward expansion of the subpolar gyres, (ii) the collapse of the overturning circulation related to North Atlantic Deep Water formation leading to surface cooling in the North Atlantic, and (iii) significant equatorward eddy heat transport near Antarctica. However, quantitative details significantly depend on the chosen resolution. The warming around Antarctica is substantially larger for the noneddying configuration (˜5.5°C) than for the eddying configuration (˜2.5°C). This is a consequence of the subpolar mean flow which partitions differently into gyres and circumpolar current at different resolutions. We conclude that for a deciphering of the different mechanisms active in Eocene-Oligocene climate change detailed analyses of the pathways of heat in the different climate subsystems are crucial in order to clearly identify the physical processes actually at work.

  12. Multidecadal climate variability of global lands and oceans

    USGS Publications Warehouse

    McCabe, G.J.; Palecki, M.A.

    2006-01-01

    Principal components analysis (PCA) and singular value decomposition (SVD) are used to identify the primary modes of decadal and multidecadal variability in annual global Palmer Drought Severity Index (PDSI) values and sea-surface temperature (SSTs). The PDSI and SST data for 1925-2003 were detrended and smoothed (with a 10-year moving average) to isolate the decadal and multidecadal variability. The first two principal components (PCs) of the PDSI PCA explained almost 38% of the decadal and multidecadal variance in the detrended and smoothed global annual PDSI data. The first two PCs of detrended and smoothed global annual SSTs explained nearly 56% of the decadal variability in global SSTs. The PDSI PCs and the SST PCs are directly correlated in a pairwise fashion. The first PDSI and SST PCs reflect variability of the detrended and smoothed annual Pacific Decadal Oscillation (PDO), as well as detrended and smoothed annual Indian Ocean SSTs. The second set of PCs is strongly associated with the Atlantic Multidecadal Oscillation (AMO). The SVD analysis of the cross-covariance of the PDSI and SST data confirmed the close link between the PDSI and SST modes of decadal and multidecadal variation and provided a verification of the PCA results. These findings indicate that the major modes of multidecadal variations in SSTs and land-surface climate conditions are highly interrelated through a small number of spatially complex but slowly varying teleconnections. Therefore, these relations may be adaptable to providing improved baseline conditions for seasonal climate forecasting. Published in 2006 by John Wiley & Sons, Ltd.

  13. GLOBEC: Global Ocean Ecosystems Dynamics: A component of the US Global Change Research Program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    GLOBEC (GLOBal ocean ECosystems dynamics) is a research initiative proposed by the oceanographic and fisheries communities to address the question of how changes in global environment are expected to affect the abundance and production of animals in the sea. The approach to this problem is to develop a fundamental understanding of the mechanisms that determine both the abundance of key marine animal populations and their variances in space and time. The assumption is that the physical environment is a major contributor to patterns of abundance and production of marine animals, in large part because the planktonic life stages typical of most marine animals are intrinsically at the mercy of the fluid motions of the medium in which they live. Consequently, the authors reason that a logical approach to predicting the potential impact of a globally changing environment is to understand how the physical environment, both directly and indirectly, contributes to animal abundance and its variability in marine ecosystems. The plans for this coordinated study of of the potential impact of global change on ocean ecosystems dynamics are discussed.

  14. Stochastic Modeling and Global Warming Trend Extraction For Ocean Acoustic Travel Times.

    DTIC Science & Technology

    1995-01-06

    consideration and that these models can not currently be relied upon by themselves to predict global warming . Experimental data is most certainly needed, not...only to measure global warming itself, but to help improve the ocean model themselves. (AN)

  15. The oceanic cycle and global atmospheric budget of carbonyl sulfide

    SciTech Connect

    Weiss, P.S.

    1994-12-31

    A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

  16. Toward an internal gravity wave spectrum in global ocean models

    NASA Astrophysics Data System (ADS)

    Müller, Malte; Arbic, Brian K.; Richman, James G.; Shriver, Jay F.; Kunze, Eric L.; Scott, Robert B.; Wallcraft, Alan J.; Zamudio, Luis

    2015-05-01

    High-resolution global ocean models forced by atmospheric fields and tides are beginning to display realistic internal gravity wave spectra, especially as model resolution increases. This paper examines internal waves in global simulations with 0.08° and 0.04° (~8 and 4 km) horizontal resolutions, respectively. Frequency spectra of internal wave horizontal kinetic energy in the North Pacific lie closer to observations in the 0.04° simulation than in the 0.08° simulation. The horizontal wave number and frequency (K-ω) kinetic energy spectra contain peaks in the semidiurnal tidal band and near-inertial band, along with a broadband frequency continuum aligned along the linear dispersion relations of low-vertical-mode internal waves. Spectral kinetic energy transfers describe the rate at which nonlinear mechanisms remove or supply kinetic energy in specific K-ω ranges. Energy is transferred out of low-mode inertial and semidiurnal internal waves into a broad continuum of higher-frequency and higher-wave number internal waves.

  17. Ocean color: Availability of the global data set

    NASA Astrophysics Data System (ADS)

    Feldman, Gene; Kuring, Norman; Ng, Carolyn; Esaias, Wayne; McClain, Chuck; Elrod, Jane; Maynard, Nancy; Endres, Dan; Evans, Robert; Brown, Jim; Walsh, Sue; Carle, Mark; Podesta, Guillermo

    The National Aeronautics and Space Administration/ Goddard Space Flight Center's Nimbus Project Office, in collaboration with the NASA/GSFC Space Data and Computing Division, the NASA/GSFC Laboratory for Oceans and the University of Miami/Rosenstiel School of Marine and Atmospheric Science, have undertaken to process all data acquired by the Coastal Zone Color Scanner (CZCS) to Earth-gridded geophysical values and to provide ready access to data products [Esaias et al., 1986].An end-to-end data system utilizing recent advances in data base management and both digital and analog optical disc storage technologies has been developed to handle the processing, analysis, quality control, archiving and distribution of this data set. A more complete description of this system, which has been fully operational for the past 2 years, is in preparation. The entire Level-1 data set (see Tables 1, 2) has been copied from magnetic tape to digital optical disc, and all data from the first 32 months (50% of the total scenes acquired, and covering the period November 1978 through June 1981) have been processed to Levels 2 and 3 and are now available for distribution. The remainder of the data set should be completed and released by fall 1989.

  18. Ocean topography mapping, improvement of the marine geoid, and global permanent ocean circulation studies from TOPEX/Poseidon altimeter data

    NASA Technical Reports Server (NTRS)

    Marsh, James G.; Lerch, F. J.; Koblinsky, C. J.; Nerem, R. S.; Klosko, S. M.; Williamson, R. G.

    1991-01-01

    The TOPEX/POSEIDON altimeter measurements will be the first global observations of the sea surface with accuracy sufficient to make quantitative determinations of the ocean's general circulation and its variations. These measurements are an important step to understanding global change in the ocean and its impact on the climate. Our investigation will focus on the examination of features in the sea surface elevation at the largest spatial and temporal scales. TOPEX/POSEIDON altimeter measurements will be used in conjunction with observations from past satellite-altimeter missions, such as NASA's GEOS-3 and Seasat, the U.S. Navy's Geosat and SALT, and the European Remote Sensing satellite in order to address the following issues: (1) Improve models of the marine geoid, especially at wavelengths needed to understand the basin-scale ocean dynamic topograpy. (2) Measure directly from the altimeter data the expression of the mean global ocean circulation in the sea surface at the largest scales through a simultaneous solution for gravity, orbital, and oceanographic parameters. (3) Examine the sea surface measurements for changes in global ocean mass or volume, interannual variations in the basin-scale ocean circulation, and annual changes in the heating and cooling of the upper ocean.

  19. Ocean topography mapping, improvement of the marine geoid, and global permanent ocean circulation studies from TOPEX/Poseidon altimeter data

    NASA Technical Reports Server (NTRS)

    Marsh, James G.; Lerch, F. J.; Koblinsky, C. J.; Nerem, R. S.; Klosko, S. M.; Williamson, R. G.

    1991-01-01

    The TOPEX/POSEIDON altimeter measurements will be the first global observations of the sea surface with accuracy sufficient to make quantitative determinations of the ocean's general circulation and its variations. These measurements are an important step to understanding global change in the ocean and its impact on the climate. Our investigation will focus on the examination of features in the sea surface elevation at the largest spatial and temporal scales. TOPEX/POSEIDON altimeter measurements will be used in conjunction with observations from past satellite-altimeter missions, such as NASA's GEOS-3 and Seasat, the U.S. Navy's Geosat and SALT, and the European Remote Sensing satellite in order to address the following issues: (1) Improve models of the marine geoid, especially at wavelengths needed to understand the basin-scale ocean dynamic topograpy. (2) Measure directly from the altimeter data the expression of the mean global ocean circulation in the sea surface at the largest scales through a simultaneous solution for gravity, orbital, and oceanographic parameters. (3) Examine the sea surface measurements for changes in global ocean mass or volume, interannual variations in the basin-scale ocean circulation, and annual changes in the heating and cooling of the upper ocean.

  20. Comparison of retrospective analyses of the global ocean heat content

    NASA Astrophysics Data System (ADS)

    Chepurin, Gennady A.; Carton, James A.

    1999-07-01

    In this study, we compare seven retrospective analyses of basin- to global-scale upper ocean temperature. The analyses span a minimum of 10 years during the 50-year period since World War II. Three of the analyses (WOA-94, WHITE, BMRC) are based on objective analysis and thus, do not rely on a numerical forecast model. The remaining four (NCEP, WAJSOWICZ, ROSATI, SODA) are based on data assimilation in which the numerical forecast is provided by some form of the Geophysical Fluid Dynamics Laboratory Modular Ocean Model driven by historical winds. The comparison presented here is limited to heat content in the upper 250 m, information that is available for all analyses. The results are presented in three frequency bands: seasonal, interannual (periods of 1-5 years), and decadal (periods of 5-25 years). At seasonal frequencies, all of the analyses are quite similar. Otherwise, the differences among analyses are limited to the regions of the western boundary currents, and some regions in the Southern Hemisphere. At interannual frequencies, significant differences appear between the objective analyses and the data assimilation analyses. Along the equator in the Pacific, where variability is dominated by El Niño, the objective analyses have somewhat noisier fields, as well as reduced variance prior to 1980 due to lack of observations. Still, the correlation among analyses generally exceeds 80% in this region. Along the equator in the Atlantic, the correlation is lower (30-60%) although inspection of the time series shows that the same biennial progression of warm and cool events appears in all analyses since 1980. In the midlatitude Pacific agreement among objective analyses and data assimilation analyses is good. The analysis of Rosati et al. [Rosati, A., Gudgel, R., Miyakoda, K., 1995. Decadal analysis produced from an ocean assimilation system. Mon. Weather Rev., 123, 2, 206.] differs somewhat from the others apparently because in this analysis, the forecast model

  1. Millennial-scale projection of oceanic oxygen change due to global warming

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akitomo; Abe-Ouchi, Ayako; Shigemitsu, Masahito; Oka, Akira; Takahashi, Kunio; Ohgaito, Rumi; Yamanaka, Yasuhiro

    2016-04-01

    Global warming is expected to globally decrease ocean oxygen concentrations by sea surface warming and ocean circulation change. Oxygen reduction is expected to persist for a thousand years or more, even after atmospheric carbon dioxide stops rising. However, long-term changes in ocean oxygen and circulation are still unclear. Here we simulate multimillennium changes in ocean circulation and oxygen under doubling and quadrupling of atmospheric carbon dioxide, using GCM (MIROC) and an offline biogeochemical model. In the first 500 years, global oxygen concentration decreases, consistent with previous studies. Thereafter, however, the oxygen concentration in the deep ocean globally recovers and overshoots at the end of the simulations, despite surface oxygen decrease and weaker AMOC. This is because, after the initial cessation, the recovery and overshooting of deep ocean convection in the Weddell Sea enhance ventilation and supply oxygen-rich surface waters to deep ocean. Another contributor to deep ocean oxygenation is seawater warming, which reduces the export production and shifts the organic matter remineralization to the upper water column. Our results indicate that the change in ocean circulation in the Southern Ocean potentially drives millennial-scale oxygenation in deep ocean, which is opposite to the centennial-scale global oxygen reduction and general expectation.

  2. High storage rates of anthropogenic CO_{2} in the Indian sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Murata, Akihiko; Kumamoto, Yu-ichiro; Sasaki, Ken-ichi

    2017-04-01

    Using high-quality data for CO2-system and related properties collected 17 years apart through international observation programs, we examined decadal-scale increases of anthropogenic CO2 along a zonal section at nominal 62˚ S ranging from 30˚ E to 160˚ E in the Indian sector of the Southern Ocean. In contrast to previous studies, increases of anthropogenic CO2 were largest (> 9.0 μmol kg-1) in Antarctic Bottom Water, where little storage of anthropogenic CO2 has been reported. Significant increases of anthropogenic CO2 in bottom and/or deep waters were detected through the section, although they became reduced in magnitude and depth range west of 110˚ E. Vertical distributions of anthropogenic CO2 showed significant positive correlations with decadal-scale changes in CFC-12, a proxy of circulation and ventilation, meaning that the distributions were mainly controlled by physical processes. Comparison of increases of anthropogenic CO2 between calculation methods with and without total alkalinity presented differences of increases of anthropogenic CO2west of 50˚ E. This is probably because decreases in production of particulate inorganic carbons in the Southern Ocean. The highest storage rate of anthropogenic CO2 was estimated to be 1.1 ± 0.6 mol m-2 a-1 at longitudes 130˚ -160˚ E. The results highlight storage rates higher than ever reported in the Southern Ocean, where very low storage of anthropogenic CO2 has been evidenced.

  3. Comparisons of anthropogenic CO2 storage between Models and Observations in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Rios, A. F.; Velo, A.; Steinfeldt, R.; Khatiwala, S.; Bopp, L.; Perez, F. F.

    2012-04-01

    Observational methods to estimate anthropogenic CO2 (Cant) are applied to a high quality dataset of the Atlantic Ocean from 65°N - 80°S. The database consists of CARINA and GLODAP datasets (76363 data) that was extended to 104043 using a local MLR and neural networks to recover carbon data available for Cant computations, assuming no temporal variability of alkalinity. A multiparametric method using conservative water mass properties of WOA'09 for interpolation was applied to the Cant estimated using the observational methods (Phi-Ct°, TrOCA, TTD) to obtain the Cant storage in the Atlantic Ocean. These Cant storages were compared with four model outputs (LSC, CSIRO, ETH, WHOI) and an inverse solution based on constraining the oceans transport Green function with observations. All Cant storages give similar spatial distributions however, the output of the models give systematically 75% lower Cant storage than the observational methods. We find even more marked difference when we consider the water column below 5°C that represent the 82% of the total volume, where the Cant storage given by models are two and a half times lower that the observational methods, where the highest differences appear south of 40°S. While in waters above 5 ° C, there is a good agreement with a difference of only 20% that is located in the subtropical North Atlantic area. To evaluate the areas where the highest discrepancies occur, a specific study through the vertical profiles is carried out. These results will help to assess biogeochemical ocean models and coupled climate-carbon models.

  4. Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

    NASA Astrophysics Data System (ADS)

    Myriokefalitakis, Stelios; Nenes, Athanasios; Baker, Alex R.; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2016-12-01

    The atmospheric cycle of phosphorus (P) is parameterized here in a state-of-the-art global 3-D chemistry transport model, taking into account primary emissions of total P (TP) and soluble P (DP) associated with mineral dust, combustion particles from natural and anthropogenic sources, bioaerosols, sea spray and volcanic aerosols. For the present day, global TP emissions are calculated to be roughly 1.33 Tg-P yr-1, with the mineral sources contributing more than 80 % to these emissions. The P solubilization from mineral dust under acidic atmospheric conditions is also parameterized in the model and is calculated to contribute about one-third (0.14 Tg-P yr-1) of the global DP atmospheric source. To our knowledge, a unique aspect of our global study is the explicit modeling of the evolution of phosphorus speciation in the atmosphere. The simulated present-day global annual DP deposition flux is 0.45 Tg-P yr-1 (about 40 % over oceans), showing a strong spatial and temporal variability. Present-day simulations of atmospheric P aerosol concentrations and deposition fluxes are satisfactory compared with available observations, indicating however an underestimate of about 70 % on current knowledge of the sources that drive the P atmospheric cycle. Sensitivity simulations using preindustrial (year 1850) anthropogenic and biomass burning emission scenarios showed a present-day increase of 75 % in the P solubilization flux from mineral dust, i.e., the rate at which P is converted into soluble forms, compared to preindustrial times, due to increasing atmospheric acidity over the last 150 years. Future reductions in air pollutants due to the implementation of air-quality regulations are expected to decrease the P solubilization flux from mineral dust by about 30 % in the year 2100 compared to the present day. Considering, however, that all the P contained in bioaerosols is readily available for uptake by marine organisms, and also accounting for all other DP sources, a total

  5. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming

    NASA Astrophysics Data System (ADS)

    Huang, Ping; Lin, I.-I.; Chou, Chia; Huang, Rong-Hui

    2015-05-01

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

  6. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming.

    PubMed

    Huang, Ping; Lin, I-I; Chou, Chia; Huang, Rong-Hui

    2015-05-18

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

  7. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming

    PubMed Central

    Huang, Ping; Lin, I. -I; Chou, Chia; Huang, Rong-Hui

    2015-01-01

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas. PMID:25982028

  8. Ocean in peril: reforming the management of global ocean living resources in areas beyond national jurisdiction.

    PubMed

    Gjerde, Kristina M; Currie, Duncan; Wowk, Kateryna; Sack, Karen

    2013-09-30

    This article presents the outcome of research aimed at assisting governments in meeting their commitments and legal obligations for sustainable fisheries, based on increasing evidence that global fisheries are in crisis. The article assesses the effectiveness of the existing legal and institutional framework for high seas living resources. It focuses on: (1) the role of regional fisheries management organizations (RFMOs); (2) tools for compliance and enforcement to stem illegal fishing; and (3) mechanisms for habitat protection. The article further highlights a variety of options for addressing key weaknesses and gaps in current ocean governance, including United Nations General Assembly (UNGA) resolutions, reforms at the regional level, as well as a possible new legal instrument, with a view to informing international discussions on ways to ensure the sustainable use of high seas resources without compromising the health of the marine environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Ocean deoxygenation, the global phosphorus cycle and the possibility of human-caused large-scale ocean anoxia.

    PubMed

    Watson, Andrew J; Lenton, Timothy M; Mills, Benjamin J W

    2017-09-13

    The major biogeochemical cycles that keep the present-day Earth habitable are linked by a network of feedbacks, which has led to a broadly stable chemical composition of the oceans and atmosphere over hundreds of millions of years. This includes the processes that control both the atmospheric and oceanic concentrations of oxygen. However, one notable exception to the generally well-behaved dynamics of this system is the propensity for episodes of ocean anoxia to occur and to persist for 10(5)-10(6) years, these ocean anoxic events (OAEs) being particularly associated with warm 'greenhouse' climates. A powerful mechanism responsible for past OAEs was an increase in phosphorus supply to the oceans, leading to higher ocean productivity and oxygen demand in subsurface water. This can be amplified by positive feedbacks on the nutrient content of the ocean, with low oxygen promoting further release of phosphorus from ocean sediments, leading to a potentially self-sustaining condition of deoxygenation. We use a simple model for phosphorus in the ocean to explore this feedback, and to evaluate the potential for humans to bring on global-scale anoxia by enhancing P supply to the oceans. While this is not an immediate global change concern, it is a future possibility on millennial and longer time scales, when considering both phosphate rock mining and increased chemical weathering due to climate change. Ocean deoxygenation, once begun, may be self-sustaining and eventually could result in long-lasting and unpleasant consequences for the Earth's biosphere.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'. © 2017 The Authors.

  10. Ocean deoxygenation, the global phosphorus cycle and the possibility of human-caused large-scale ocean anoxia

    PubMed Central

    Lenton, Timothy M.; Mills, Benjamin J. W.

    2017-01-01

    The major biogeochemical cycles that keep the present-day Earth habitable are linked by a network of feedbacks, which has led to a broadly stable chemical composition of the oceans and atmosphere over hundreds of millions of years. This includes the processes that control both the atmospheric and oceanic concentrations of oxygen. However, one notable exception to the generally well-behaved dynamics of this system is the propensity for episodes of ocean anoxia to occur and to persist for 105–106 years, these ocean anoxic events (OAEs) being particularly associated with warm ‘greenhouse’ climates. A powerful mechanism responsible for past OAEs was an increase in phosphorus supply to the oceans, leading to higher ocean productivity and oxygen demand in subsurface water. This can be amplified by positive feedbacks on the nutrient content of the ocean, with low oxygen promoting further release of phosphorus from ocean sediments, leading to a potentially self-sustaining condition of deoxygenation. We use a simple model for phosphorus in the ocean to explore this feedback, and to evaluate the potential for humans to bring on global-scale anoxia by enhancing P supply to the oceans. While this is not an immediate global change concern, it is a future possibility on millennial and longer time scales, when considering both phosphate rock mining and increased chemical weathering due to climate change. Ocean deoxygenation, once begun, may be self-sustaining and eventually could result in long-lasting and unpleasant consequences for the Earth's biosphere. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’. PMID:28784709

  11. Analysis of 50-y record of surface (137)Cs concentrations in the global ocean using the HAM-global database.

    PubMed

    Inomata, Yayoi; Aoyama, Michio; Hirose, Katsumi

    2009-01-01

    We investigated spatial and temporal variations in (137)Cs concentrations in the surface waters of the global ocean for the period from 1957 to 2005 using the "HAM database - a global version". Based on the 0.5-y average value of (137)Cs concentrations in the surface water in each sea area, we classified the temporal variations into four types. (1) In the North Pacific Ocean where there was high fallout from atmospheric nuclear weapons tests, the rates of decrease in the (137)Cs concentrations changed over the five decades: the rate of decrease from the 1950s to the 1970s was much faster than that after the 1970s, and the (137)Cs concentrations were almost constant after the 1990s. Latitudinal differences in (137)Cs concentrations in the North Pacific Ocean became small with time. (2) In the equatorial Pacific and Indian Oceans, the (137)Cs concentrations varied within a constant range in the 1970s and 1980s, suggesting the advection of (137)Cs from areas of high global fallout in the mid-latitudes of the North Pacific Ocean. (3) In the eastern South Pacific and Atlantic Oceans (south of 40 degrees S), the concentrations decreased exponentially over the five decades. (4) In the Arctic and North Atlantic Oceans, including marginal seas, (137)Cs concentrations were strongly controlled by discharge from nuclear reprocessing plants after the late 1970s. The apparent half-residence times of (137)Cs in the surface waters of the global ocean from 1970 to 2005 ranged from 4.5 to 36.8 years. The apparent half-residence times were longer in the equatorial region and shorter in the higher latitudes. There was no notable difference between the latitudinal distributions of the apparent half-residence times in the Pacific and Indian Oceans. These results suggest that (137)Cs in the North Pacific Ocean is transported to the equatorial, South Pacific, and Indian Oceans by the oceanic circulation.

  12. Decadal Ocean Heat Content Westward Shift in the Indian Ocean during the Global Surface Warming and Hiatus

    NASA Astrophysics Data System (ADS)

    Wu, X.; Yan, X. H.; Li, Y.

    2015-12-01

    Understanding the ocean's role in Earth's energy budget is fundamental to evaluate climate variability and change, including the rate of global warming and the recent 18-years' so-called Global Surface Warming Hiatus (GSWH). Previous studies have shown that basin-wide warming in the Atlantic Ocean triggers the intensification of trade wind and wind-driven circulation since late 1990s, resulting in Global Surface Warming Hiatus (GSWH). A recent work revealed that missing heat in the Pacific during the GSWH was transported to the Indian Ocean by the Indonesia throughflow. It brings the Indian Ocean to the platform of the GSWH study and suggests that the global ocean is at play in the GSWH and in the ocean heat content (OHC) westwards shifting. The westwards shifting of the OHC was detected from in-situ data and model/in-situ reanalysis data. The shifting has a period of about 30 years, and takes about 60 years to travel from the eastern Pacific to the western Atlantic. Heat was distributed to deeper layers after the warm OHC passed the southern tip of the Africa continent. This may shed light on the understanding of the physical mechanisms for the multi-decadal climate variability.

  13. A global probabilistic study of the ocean heat content low-frequency variability: Atmospheric forcing versus oceanic chaos

    NASA Astrophysics Data System (ADS)

    Sérazin, Guillaume; Jaymond, Alexandre; Leroux, Stéphanie; Penduff, Thierry; Bessières, Laurent; Llovel, William; Barnier, Bernard; Molines, Jean-Marc; Terray, Laurent

    2017-06-01

    A global 1/4° ocean/sea ice 50-member ensemble simulation is used to disentangle the low-frequency imprints of the atmospherically forced oceanic variability and of the chaotic intrinsic oceanic variability (IOV) on the large-scale (10° × 10°) ocean heat content (OHC) between 1980 and 2010. The IOV explains most of the interannual-to-decadal large-scale OHC variance over substantial fractions of the global ocean area that increase with depth: 9%, 22%, and 31% in the 0-700 m, 700-2000 m and 2000 m bottom layers, respectively. Such areas concern principally eddy-active regions, mostly found in the Southern Ocean and in western boundary current extensions, and also concern the subtropical gyres at intermediate and deep levels. The oceanic chaos may also induce random multidecadal fluctuations so that large-scale regional OHC trends computed on the 1980-2010 period cannot be unambiguously attributed to the atmospheric forcing in several oceanic basins at various depths. These results are likely to raise detection and attribution issues from real observations.

  14. Revisiting ocean carbon sequestration by direct injection: a global carbon budget perspective

    NASA Astrophysics Data System (ADS)

    Reith, Fabian; Keller, David P.; Oschlies, Andreas

    2016-11-01

    In this study we look beyond the previously studied effects of oceanic CO2 injections on atmospheric and oceanic reservoirs and also account for carbon cycle and climate feedbacks between the atmosphere and the terrestrial biosphere. Considering these additional feedbacks is important since backfluxes from the terrestrial biosphere to the atmosphere in response to reducing atmospheric CO2 can further offset the targeted reduction. To quantify these dynamics we use an Earth system model of intermediate complexity to simulate direct injection of CO2 into the deep ocean as a means of emissions mitigation during a high CO2 emission scenario. In three sets of experiments with different injection depths, we simulate a 100-year injection period of a total of 70 GtC and follow global carbon cycle dynamics over another 900 years. In additional parameter perturbation runs, we varied the default terrestrial photosynthesis CO2 fertilization parameterization by ±50 % in order to test the sensitivity of this uncertain carbon cycle feedback to the targeted atmospheric carbon reduction through direct CO2 injections. Simulated seawater chemistry changes and marine carbon storage effectiveness are similar to previous studies. As expected, by the end of the injection period avoided emissions fall short of the targeted 70 GtC by 16-30 % as a result of carbon cycle feedbacks and backfluxes in both land and ocean reservoirs. The target emissions reduction in the parameter perturbation simulations is about 0.2 and 2 % more at the end of the injection period and about 9 % less to 1 % more at the end of the simulations when compared to the unperturbed injection runs. An unexpected feature is the effect of the model's internal variability of deep-water formation in the Southern Ocean, which, in some model runs, causes additional oceanic carbon uptake after injection

  15. Climatic and anthropogenic factors affecting river discharge to the global ocean, 1951-2000

    USGS Publications Warehouse

    Milliman, John D.; Farnsworth, K.L.; Jones, P.D.; Xu, K.H.; Smith, L.C.

    2008-01-01

    During the last half of the 20th century, cumulative annual discharge from 137 representative rivers (watershed areas ranging from 0.3 to 6300 ?? 103??km2) to the global ocean remained constant, although annual discharge from about one-third of these rivers changed by more than 30%. Discharge trends for many rivers reflected mostly changes in precipitation, primarily in response to short- and longer-term atmospheric-oceanic signals; with the notable exception of the Parana, Mississippi, Niger and Cunene rivers, few of these "normal" rivers experienced significant changes in either discharge or precipitation. Cumulative discharge from many mid-latitude rivers, in contrast, decreased by 60%, reflecting in large part impacts due to damming, irrigation and interbasin water transfers. A number of high-latitude and high-altitude rivers experienced increased discharge despite generally declining precipitation. Poorly constrained meteorological and hydrological data do not seem to explain fully these "excess" rivers; changed seasonality in discharge, decreased storage and/or decreased evapotranspiration also may play important roles. ?? 2008 Elsevier B.V. All rights reserved.

  16. How Well Has Global Ocean Heat Content Variability Been Measured?

    NASA Astrophysics Data System (ADS)

    Nelson, A.; Weiss, J.; Fox-Kemper, B.; Fabienne, G.

    2016-12-01

    We introduce a new strategy that uses synthetic observations of an ensemble of model simulations to test the fidelity of an observational strategy, quantifying how well it captures the statistics of variability. We apply this test to the 0-700m global ocean heat content anomaly (OHCA) as observed with in-situ measurements by the Coriolis Dataset for Reanalysis (CORA), using the Community Climate System Model (CCSM) version 3.5. One-year running mean OHCAs for the years 2005 onward are found to faithfully capture the variability. During these years, synthetic observations of the model are strongly correlated at 0.94±0.06 with the actual state of the model. Overall, sub-annual variability and data before 2005 are signi cantly a ffected by the variability of the observing system. In contrast, the sometimes-used weighted integral of observations is not a good indicator of OHCA as variability in the observing system contaminates dynamical variability.

  17. A Multiyear Dataset of SSM/I-Derived Global Ocean Surface Turbulent Fluxes

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The surface turbulent fluxes of momentum, latent heat, and sensible heat over global oceans are essential to weather, climate and ocean problems. Evaporation is a key component of the hydrological cycle and the surface heat budget, while the wind stress is the major forcing for driving the oceanic circulation. The global air-sea fluxes of momentum, latent and sensible heat, radiation, and freshwater (precipitation-evaporation) are the forcing for driving oceanic circulation and, hence, are essential for understanding the general circulation of global oceans. The global air-sea fluxes are required for driving ocean models and validating coupled ocean-atmosphere global models. We have produced a 7.5-year (July 1987-December 1994) dataset of daily surface turbulent fluxes over the global oceans from the Special Sensor microwave/Imager (SSM/I) data. Daily turbulent fluxes were derived from daily data of SSM/I surface winds and specific humidity, National Centers for Environmental Prediction (NCEP) sea surface temperatures, and European Centre for Medium-Range Weather Forecasts (ECMWF) air-sea temperature differences, using a stability-dependent bulk scheme. The retrieved instantaneous surface air humidity (with a 25-km resolution) validated well with that of the collocated radiosonde observations over the global oceans. Furthermore, the retrieved daily wind stresses and latent heat fluxes were found to agree well with that of the in situ measurements (IMET buoy, RV Moana Wave, and RV Wecoma) in the western Pacific warm pool during the TOGA COARE intensive observing period (November 1992-February 1993). The global distributions of 1988-94 seasonal-mean turbulent fluxes will be presented. In addition, the global distributions of 1990-93 annual-means turbulent fluxes and input variables will be compared with those of UWM/COADS covering the same period. The latter is based on the COADS (comprehensive ocean-atmosphere data set) and is recognized to be one of the best

  18. Global rates of mantle serpentinization and H2 release at oceanic transform faults

    NASA Astrophysics Data System (ADS)

    Ruepke, Lars; Hasenclever, Joerg

    2017-04-01

    The cycling of seawater through the ocean floor is the dominant mechanism of biogeochemical exchange between the solid earth and the global ocean. Crustal fluid flow appears to be typically associated with major seafloor structures, and oceanic transform faults (OTF) are one of the most striking yet poorly understood features of the global mid-ocean ridge systems. Fracture zones and transform faults have long been hypothesized to be sites of substantial biogeochemical exchange between the solid Earth and the global ocean. This is particularly interesting with regard to the ocean biome. Deep ocean ecosystems constitute 60% of it but their role in global ocean biogeochemical cycles is much overlooked. There is growing evidence that life is supported by chemosynthesis at hydrothermal vents but also in the crust, and therefore this may be a more abundant process than previously thought. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting as it is also a mechanism of abiotic hydrogen and methane formation. Interestingly, a quantitative global assessment of mantle serpentinization at oceanic transform faults in the context of the biogeochemical exchange between the seafloor and the global ocean is still largely missing. Here we present the results of a set of 3-D thermo-mechanical model calculations that investigate mantle serpentinization at OTFs for the entire range of globally observed slip rates and fault lengths. These visco-plastic models predict the OTF thermal structure and the location of crustal-scale brittle deformation, which is a prerequisite for mantle serpentinization to occur. The results of these simulations are integrated with information on the global distribution of OTF lengths and slip rates yielding global estimates on mantle serpentinization and associated H2 release. We find that OTFs are potentially sites of intense crustal fluid flow and are in terms of H2 release

  19. A Multiyear Dataset of SSM/I-Derived Global Ocean Surface Turbulent Fluxes

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The surface turbulent fluxes of momentum, latent heat, and sensible heat over global oceans are essential to weather, climate and ocean problems. Evaporation is a key component of the hydrological cycle and the surface heat budget, while the wind stress is the major forcing for driving the oceanic circulation. The global air-sea fluxes of momentum, latent and sensible heat, radiation, and freshwater (precipitation-evaporation) are the forcing for driving oceanic circulation and, hence, are essential for understanding the general circulation of global oceans. The global air-sea fluxes are required for driving ocean models and validating coupled ocean-atmosphere global models. We have produced a 7.5-year (July 1987-December 1994) dataset of daily surface turbulent fluxes over the global oceans from the Special Sensor microwave/Imager (SSM/I) data. Daily turbulent fluxes were derived from daily data of SSM/I surface winds and specific humidity, National Centers for Environmental Prediction (NCEP) sea surface temperatures, and European Centre for Medium-Range Weather Forecasts (ECMWF) air-sea temperature differences, using a stability-dependent bulk scheme. The retrieved instantaneous surface air humidity (with a 25-km resolution) validated well with that of the collocated radiosonde observations over the global oceans. Furthermore, the retrieved daily wind stresses and latent heat fluxes were found to agree well with that of the in situ measurements (IMET buoy, RV Moana Wave, and RV Wecoma) in the western Pacific warm pool during the TOGA COARE intensive observing period (November 1992-February 1993). The global distributions of 1988-94 seasonal-mean turbulent fluxes will be presented. In addition, the global distributions of 1990-93 annual-means turbulent fluxes and input variables will be compared with those of UWM/COADS covering the same period. The latter is based on the COADS (comprehensive ocean-atmosphere data set) and is recognized to be one of the best

  20. An estimate of the global distribution of radon emissions from the ocean

    NASA Astrophysics Data System (ADS)

    Schery, S. D.; Huang, S.

    2004-10-01

    There is a need for improved estimates of the radon (222Rn) flux density from the ocean for use in the modeling and interpretation of atmospheric radon in global climate and air pollution studies. We use a modification of a frequently used model of gas transfer to generate global predictions of ocean radon flux density for each month of the year (climate averaged) on a 192 by 94 global grid. Compared with the often-used approximation of a constant radon flux from the ocean, the model's predictions indicate large variations over regions of the ocean (a factor of ten is not uncommon). For example, latitude bands near the equator and Southern Ocean are predicted to emit relatively high average radon flux compared with other latitude bands. The predicted annually-averaged flux density from the ocean is 0.0382 mBq m-2 s-1 (0.00182 atoms cm-2 s-1), smaller than some commonly-used estimates.

  1. Global oceanic emission of ammonia: Constraints from seawater and atmospheric observations

    NASA Astrophysics Data System (ADS)

    Paulot, F.; Jacob, D. J.; Johnson, M. T.; Bell, T. G.; Baker, A. R.; Keene, W. C.; Lima, I. D.; Doney, S. C.; Stock, C. A.

    2015-08-01

    Current global inventories of ammonia emissions identify the ocean as the largest natural source. This source depends on seawater pH, temperature, and the concentration of total seawater ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models (BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high. Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed ranges. The resulting global ocean emissions is 2.5 TgN a-1, much lower than current literature values (7-23 TgN a-1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a-1). Such a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean emission of ammonia in the range 2-5 TgN a-1, comparable in magnitude to other natural sources from open fires and soils.

  2. Evaluation of Global Ocean Data Assimilation Experiment Products on South Florida Nested Simulations with the Hybrid Coordinate Ocean Model

    DTIC Science & Technology

    2009-01-01

    Ongoing simula- tions and prediction with GODAE global and basin-scale models have fulfilled the main GODAE objectives of developing state-of-the- art ...the Optimal Interpolation based Modular Ocean Data Assimilation System ( MODAS ). This system consists of daily operational 1/4° Sea Surface Height...used to project the surface information from altimetry SSH to the interior of the ocean. Relaxation to the MODAS 1/8° Sea Surface Temperature (SST

  3. Assimilation of TOPEX/POSEIDON Altimeter Data into a Global Ocean Circulation Model: Are the Results Any Good?

    NASA Technical Reports Server (NTRS)

    Fukumori, I.; Fu, L. L.; Chao, Y.

    1998-01-01

    The feasibility of assimilating satellite altimetry data into a global ocean general ocean general circulation model is studied. Three years of TOPEX/POSEIDON data is analyzed using a global, three-dimensional, nonlinear primitive equation model.

  4. Assimilation of TOPEX/POSEIDON Altimeter Data into a Global Ocean Circulation Model: Are the Results Any Good?

    NASA Technical Reports Server (NTRS)

    Fukumori, I.; Fu, L. L.; Chao, Y.

    1998-01-01

    The feasibility of assimilating satellite altimetry data into a global ocean general ocean general circulation model is studied. Three years of TOPEX/POSEIDON data is analyzed using a global, three-dimensional, nonlinear primitive equation model.

  5. Decline in global oceanic oxygen content during the past five decades.

    PubMed

    Schmidtko, Sunke; Stramma, Lothar; Visbeck, Martin

    2017-02-15

    Ocean models predict a decline in the dissolved oxygen inventory of the global ocean of one to seven per cent by the year 2100, caused by a combination of a warming-induced decline in oxygen solubility and reduced ventilation of the deep ocean. It is thought that such a decline in the oceanic oxygen content could affect ocean nutrient cycles and the marine habitat, with potentially detrimental consequences for fisheries and coastal economies. Regional observational data indicate a continuous decrease in oceanic dissolved oxygen concentrations in most regions of the global ocean, with an increase reported in a few limited areas, varying by study. Prior work attempting to resolve variations in dissolved oxygen concentrations at the global scale reported a global oxygen loss of 550 ± 130 teramoles (10(12) mol) per decade between 100 and 1,000 metres depth based on a comparison of data from the 1970s and 1990s. Here we provide a quantitative assessment of the entire ocean oxygen inventory by analysing dissolved oxygen and supporting data for the complete oceanic water column over the past 50 years. We find that the global oceanic oxygen content of 227.4 ± 1.1 petamoles (10(15) mol) has decreased by more than two per cent (4.8 ± 2.1 petamoles) since 1960, with large variations in oxygen loss in different ocean basins and at different depths. We suggest that changes in the upper water column are mostly due to a warming-induced decrease in solubility and biological consumption. Changes in the deeper ocean may have their origin in basin-scale multi-decadal variability, oceanic overturning slow-down and a potential increase in biological consumption.

  6. Decline in global oceanic oxygen content during the past five decades

    NASA Astrophysics Data System (ADS)

    Schmidtko, Sunke; Stramma, Lothar; Visbeck, Martin

    2017-02-01

    Ocean models predict a decline in the dissolved oxygen inventory of the global ocean of one to seven per cent by the year 2100, caused by a combination of a warming-induced decline in oxygen solubility and reduced ventilation of the deep ocean. It is thought that such a decline in the oceanic oxygen content could affect ocean nutrient cycles and the marine habitat, with potentially detrimental consequences for fisheries and coastal economies. Regional observational data indicate a continuous decrease in oceanic dissolved oxygen concentrations in most regions of the global ocean, with an increase reported in a few limited areas, varying by study. Prior work attempting to resolve variations in dissolved oxygen concentrations at the global scale reported a global oxygen loss of 550 ± 130 teramoles (1012 mol) per decade between 100 and 1,000 metres depth based on a comparison of data from the 1970s and 1990s. Here we provide a quantitative assessment of the entire ocean oxygen inventory by analysing dissolved oxygen and supporting data for the complete oceanic water column over the past 50 years. We find that the global oceanic oxygen content of 227.4 ± 1.1 petamoles (1015 mol) has decreased by more than two per cent (4.8 ± 2.1 petamoles) since 1960, with large variations in oxygen loss in different ocean basins and at different depths. We suggest that changes in the upper water column are mostly due to a warming-induced decrease in solubility and biological consumption. Changes in the deeper ocean may have their origin in basin-scale multi-decadal variability, oceanic overturning slow-down and a potential increase in biological consumption.

  7. On Verifying Currents and Other Features in the Hawaiian Islands Region Using Fully Coupled Ocean/Atmosphere Mesoscale Prediction System Compared to Global Ocean Model and Ocean Observations

    NASA Astrophysics Data System (ADS)

    Jessen, P. G.; Chen, S.

    2014-12-01

    This poster introduces and evaluates features concerning the Hawaii, USA region using the U.S. Navy's fully Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS-OS™) coupled to the Navy Coastal Ocean Model (NCOM). It also outlines some challenges in verifying ocean currents in the open ocean. The system is evaluated using in situ ocean data and initial forcing fields from the operational global Hybrid Coordinate Ocean Model (HYCOM). Verification shows difficulties in modelling downstream currents off the Hawaiian islands (Hawaii's wake). Comparing HYCOM to NCOM current fields show some displacement of small features such as eddies. Generally, there is fair agreement from HYCOM to NCOM in salinity and temperature fields. There is good agreement in SSH fields.

  8. Total Land Water Storage Change over 2003 - 2013 Estimated from a Global Mass Budget Approach

    NASA Technical Reports Server (NTRS)

    Dieng, H. B.; Champollion, N.; Cazenave, A.; Wada, Y.; Schrama, E.; Meyssignac, B.

    2015-01-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of -108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  9. Total land water storage change over 2003-2013 estimated from a global mass budget approach

    NASA Astrophysics Data System (ADS)

    Dieng, Habib B.; Champollion, Nicolas; Cazenave, Anny; Wada, Yoshihide; Schrama, Ernst; Meyssignac, Benoit

    2016-04-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS(the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to+0.30 ± 0.18mmyr-1 in sea level equivalent. This corresponds to a net decrease of -108 ± 64 km3 yr-1 in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  10. Total Land Water Storage Change over 2003 - 2013 Estimated from a Global Mass Budget Approach

    NASA Technical Reports Server (NTRS)

    Dieng, H. B.; Champollion, N.; Cazenave, A.; Wada, Y.; Schrama, E.; Meyssignac, B.

    2015-01-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of -108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  11. Impact of an upgraded model in the NCEP Global Ocean Data Assimilation System: The tropical Indian Ocean

    NASA Astrophysics Data System (ADS)

    Rahaman, Hasibur; Behringer, David W.; Penny, Stephen G.; Ravichandran, M.

    2016-11-01

    The National Centers for Environmental Prediction (NCEP) and the Indian National Centre for Ocean Information Services (INCOIS) produces global ocean analysis based on the Global Ocean Data Assimilation System (GODAS). This study shows how upgrades to the forward model simulations from MOM4p0d to MOM4p1 impact ocean analyses over the tropical Indian Ocean in GODAS. Three experiments were performed with same atmospheric forcing fields: (i) using MOM4p0d (GODAS_p0), (ii) using MOM4p1 (GODAS_p1), both using observed temperature and synthetic salinity, and (iii) using MOM4p1 (GODAS_p1S) assimilating both observed temperature and observed salinity. Validation with independent observations shows significant improvement of subsurface temperature and salinity in the new analysis using MOM4p1 versus MOM4p0d. There is also improvement in the upper ocean current of the equatorial Indian Ocean. The impact of observed salinity on the upper ocean surface current is marginal, but there is significant improvement in the subsurface current. The seasonal and inter-annual variability of the Wyrtki jet and the equatorial undercurrent is improved in GODAS_p1 versus GODAS_p0. All analyses reproduced the Indian Ocean dipole, with the GODAS_p1S simulated sea surface temperature (SST) the most accurate. The temperature inversion over the north Bay of Bengal (BoB) is reproduced only in GODAS_p1S. The mean sea level over BoB and equatorial Indian Ocean improved in GODAS_p1S as compared with AVISO observation. The combined model upgrade and assimilation of observed salinity led to reduced root-mean-square deviation and higher correlation coefficient values in the sea level anomaly (SLA) when compared with satellite observations.

  12. MERCATOR-Ocean monitoring and forecasting : a 4D vision of the global ocean. Data policy and applications.

    NASA Astrophysics Data System (ADS)

    Toumazou, V.; Nouel, L.; Sureau, J.; Greiner, E.; Landes, V.; Dombrowsky, E.; Charon, I.

    2003-12-01

    Mercator Ocean is a public interest grouping formed in Toulouse in early 2002 by six major players in the French oceanography community: the space agency CNES, the scientific research centre CNRS, IFREMER (the institute of marine research and exploration), the development research institute IRD, the Météo France weather service, and SHOM (the French Navy's hydrography & oceanography department). In 1995, these same organizations gave themselves seven years to achieve a challenging objective: to conceive, develop and implement France's first operational oceanography system. The unique system would be capable of describing, analysing and predicting conditions at the ocean surface and subsurface in real time, anytime, anywhere in the world, even in the most inhospitable seas. That objective was met on 17 January 2001 with the release of the first Mercator ocean bulletin, providing a two-week forecast for the entire North Atlantic. Two thousands new forecast charts are now added to the MERCATOR bulletin every week. Building on these successes, a dedicated operational oceanography team, Mercator Ocean, was set up in 2002. Mercator Ocean's mission is to deliver incremental improvements in the service provided by this new operational oceanography capability by increasing the resolution and the geographic coverage of the models used. The new high-resolution model that is now on line offers 6 km grid resolution, and the first models offering global ocean coverage will be implemented late 2003. Over the next four years, Mercator Ocean also plans to establish a European Operational Oceanography Centre in Toulouse. Objective 1. Develop an operational oceanography system using three-dimensional simulation and a high-resolution primitive-equation model capable of assimilating satellite data (from the Jason altimetry satellite in particular) and in-situ ocean observation data (particularly those gathered by the CORIOLIS centre). 2. Support applications for commercial shipping

  13. Are Global In-Situ Ocean Observations Fit-for-purpose? Applying the Framework for Ocean Observing in the Atlantic.

    NASA Astrophysics Data System (ADS)

    Visbeck, M.; Fischer, A. S.; Le Traon, P. Y.; Mowlem, M. C.; Speich, S.; Larkin, K.

    2015-12-01

    There are an increasing number of global, regional and local processes that are in need of integrated ocean information. In the sciences ocean information is needed to support physical ocean and climate studies for example within the World Climate Research Programme and its CLIVAR project, biogeochemical issues as articulated by the GCP, IMBER and SOLAS projects of ICSU-SCOR and Future Earth. This knowledge gets assessed in the area of climate by the IPCC and biodiversity by the IPBES processes. The recently released first World Ocean Assessment focuses more on ecosystem services and there is an expectation that the Sustainable Development Goals and in particular Goal 14 on the Ocean and Seas will generate new demands for integrated ocean observing from Climate to Fish and from Ocean Resources to Safe Navigation and on a healthy, productive and enjoyable ocean in more general terms. In recognition of those increasing needs for integrated ocean information we have recently launched the Horizon 2020 AtlantOS project to promote the transition from a loosely-coordinated set of existing ocean observing activities to a more integrated, more efficient, more sustainable and fit-for-purpose Atlantic Ocean Observing System. AtlantOS takes advantage of the Framework for Ocean observing that provided strategic guidance for the design of the project and its outcome. AtlantOS will advance the requirements and systems design, improving the readiness of observing networks and data systems, and engaging stakeholders around the Atlantic. AtlantOS will bring Atlantic nations together to strengthen their complementary contributions to and benefits from the internationally coordinated Global Ocean Observing System (GOOS) and the Blue Planet Initiative of the Global Earth Observation System of Systems (GEOSS). AtlantOS will fill gaps of the in-situ observing system networks and will ensure that their data are readily accessible and useable. AtlantOS will demonstrate the utility of

  14. Environmental Assessment for Potential Impacts of Ocean CO2 Storage on Marine Biogeochemical Cycles

    NASA Astrophysics Data System (ADS)

    Yamada, N.; Tsurushima, N.; Suzumura, M.; Shibamoto, Y.; Harada, K.

    2008-12-01

    Ocean CO2 storage that actively utilizes the ocean potential to dissolve extremely large amounts of CO2 is a useful option with the intent of diminishing atmospheric CO2 concentration. CO2 storage into sub-seabed geological formations is also considered as the option which has been already put to practical reconnaissance in some projects. Direct release of CO2 in the ocean storage and potential CO2 leakage from geological formations into the bottom water can alter carbonate system as well as pH of seawater. It is essential to examine to what direction and extent chemistry change of seawater induced by CO2 can affect the marine environments. Previous studies have shown direct and acute effects by increasing CO2 concentrations on physiology of marine organisms. It is also a serious concern that chemistry change can affect the rates of chemical, biochemical and microbial processes in seawater resulting in significant influences on marine biogeochemical cycles of the bioelements including carbon, nutrients and trace metals. We, AIST, have conducted a series of basic researches to assess the potential impacts of ocean CO2 storage on marine biogeochemical processes including CaCO3 dissolution, and bacterial and enzymatic decomposition of organic matter. By laboratory experiments using a special high pressure apparatus, the improved empirical equation was obtained for CaCO3 dissolution rate in the high CO2 concentrations. Based on the experimentally obtained kinetics with a numerical simulation for a practical scenario of oceanic CO2 sequestration where 50 Mton CO2 per year is continuously injected to 1,000-2,500 m depth within 100 x 333 km area for 30 years, we could illustrate precise 3-D maps for the predicted distributions of the saturation depth of CaCO3, in situ Ω value and CaCO3 dissolution rate in the western North Pacific. The result showed no significant change in the bathypelagic CaCO3 flux due to chemistry change induced by ocean CO2 sequestration. Both

  15. Ubiquitous cyanobacterial podoviruses in the global oceans unveiled through viral DNA polymerase gene sequences.

    PubMed

    Huang, Sijun; Wilhelm, Steven W; Jiao, Nianzhi; Chen, Feng

    2010-10-01

    As a major cyanophage group, cyanobacterial podoviruses are important in regulating the biomass and population structure of picocyanobacteria in the ocean. However, little is known about their biogeography in the open ocean. This study represents the first survey of the biodiversity of cyanopodoviruses in the global oceans based on the viral encoded DNA polymerase (pol) gene. A total of 303 DNA pol sequences were amplified by PCR from 10 virus communities collected in the Atlantic and Pacific oceans and the South China Sea. At least five subclusters of cyanopodoviruses were identified in these samples, and one subcluster (subcluster VIII) was found in all sampling sites and comprised approximately 50% of total sequences. The diversity index based on the DNA pol gene sequences recovered through PCR suggests that cyanopodoviruses are less diverse in these oceanic samples than in a previously studied estuarine environment. Although diverse podoviruses were present in the global ocean, each sample was dominated by one major group of cyanopodoviruses. No clear biogeographic patterns were observed using statistical analysis. A metagenomic analysis based on the Global Ocean Sampling database indicates that other types of cyanopodovirus-like DNA pol sequences were present in the global ocean. Together, our study results suggest that cyanopodoviruses are widely distributed in the ocean but their community composition varies with local environments.

  16. TARA OCEANS: A Global Analysis of Oceanic Plankton Ecosystems (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect

    Karsenti, Eric

    2013-03-01

    Eric Karsenti of EMBL delivers the closing keynote on "TARA OCEANS: A Global Analysis of Oceanic Plankton Ecosystems" at the 8th Annual Genomics of Energy & Environment Meeting on March 28, 2013 in Walnut Creek, Calif.

  17. Keeping the lights on for global ocean salinity observation

    SciTech Connect

    Durack, Paul J.; Lee, Tong; Vinogradova, Nadya T.; Stammer, Detlef

    2016-02-24

    Here, insights about climate are being uncovered thanks to improved capacities to observe ocean salinity, an essential climate variable. However, cracks are beginning to appear in the ocean observing system that require prompt attention if we are to maintain the existing, hard-won capacity into the near future.

  18. Spacebased Observation of Global Ocean Surface Wind Fields

    NASA Technical Reports Server (NTRS)

    Polito, P. S.; Liu, W. T.

    1997-01-01

    The ocean and the atmosphere are dynamically coupled by the transport of momentum which is driven by the wind shear at the sea surface. However, in situ wind measurements are relatively sparse over most of the world's ocean and are largely limited to the locations of shipping routes.

  19. Ocean color - Availability of the global data set

    NASA Technical Reports Server (NTRS)

    Feldman, Gene; Kuring, Norman; Ng, Carolyn; Esaias, Wayne; Mcclain, Chuck; Elrod, Jane; Maynard, Nancy; Endres, Dan

    1989-01-01

    The use of satellite observations of ocean color to provide reliable estimates of marine phytoplankton biomass on synoptic scales is examined. An overview is given of the Coastal Zone Color Scanner data processing system. The archiving and distribution of ocean color data are discussed, and NASA-sponsored archive sites are listed.

  20. Global Pattern of Dissection on Mars and the Northern Ocean Hypothesis

    NASA Astrophysics Data System (ADS)

    Stepinski, T. F.; Luo, W.

    2010-03-01

    Global distribution of valley networks on Mars is accounted for by a weather pattern that follows from the existence of a northern ocean; precipitation is restricted to the regions located directly south of the dichotomy boundary.

  1. Warming up, turning sour, losing breath: ocean biogeochemistry under global change.

    PubMed

    Gruber, Nicolas

    2011-05-28

    In the coming decades and centuries, the ocean's biogeochemical cycles and ecosystems will become increasingly stressed by at least three independent factors. Rising temperatures, ocean acidification and ocean deoxygenation will cause substantial changes in the physical, chemical and biological environment, which will then affect the ocean's biogeochemical cycles and ecosystems in ways that we are only beginning to fathom. Ocean warming will not only affect organisms and biogeochemical cycles directly, but will also increase upper ocean stratification. The changes in the ocean's carbonate chemistry induced by the uptake of anthropogenic carbon dioxide (CO(2)) (i.e. ocean acidification) will probably affect many organisms and processes, although in ways that are currently not well understood. Ocean deoxygenation, i.e. the loss of dissolved oxygen (O(2)) from the ocean, is bound to occur in a warming and more stratified ocean, causing stress to macro-organisms that critically depend on sufficient levels of oxygen. These three stressors-warming, acidification and deoxygenation-will tend to operate globally, although with distinct regional differences. The impacts of ocean acidification tend to be strongest in the high latitudes, whereas the low-oxygen regions of the low latitudes are most vulnerable to ocean deoxygenation. Specific regions, such as the eastern boundary upwelling systems, will be strongly affected by all three stressors, making them potential hotspots for change. Of additional concern are synergistic effects, such as ocean acidification-induced changes in the type and magnitude of the organic matter exported to the ocean's interior, which then might cause substantial changes in the oxygen concentration there. Ocean warming, acidification and deoxygenation are essentially irreversible on centennial time scales, i.e. once these changes have occurred, it will take centuries for the ocean to recover. With the emission of CO(2) being the primary driver

  2. Strong coupling among Antarctic ice shelves, ocean circulation and sea ice in a global sea-ice - ocean circulation model

    NASA Astrophysics Data System (ADS)

    Sergienko, Olga

    2016-04-01

    The thermodynamic effects of Antarctic ice shelf interaction with ocean circulation are investigated using a global, high-resolution, isopycnal ocean-circulation model coupled to a sea-ice model. The model uses NASA MERRA Reanalysis from 1992 to 2011 as atmospheric forcing. The simulated long-period variability of ice-shelf melting/freezing rates differ across geographic locations. The ice shelves in Antarctic Peninsula, Amundsen and Bellingshausen sea embayments and the Amery Ice Shelf experience an increase in melting starting from 2005. This increase in melting is due to an increase in the subsurface (100-500 m) ocean heat content in the embayments of these ice shelves, which is caused by an increase in sea-ice concentration after 2005, and consequent reduction of the heat loss to the atmosphere. Our simulations provide a strong evidence for a coupling between ocean circulation, sea ice and ice shelves.

  3. Role of Indian Ocean SST variability on the recent global warming hiatus

    NASA Astrophysics Data System (ADS)

    Arora, Anika; Rao, Suryachandra A.; Chattopadhyay, R.; Goswami, Tanmoy; George, Gibies; Sabeerali, C. T.

    2016-08-01

    Previous studies have shown a slowdown in the warming rate of the annual mean global surface temperature in the recent decade and it is referred to as the hiatus in global warming. Some recent studies have suggested that the hiatus in global warming is possibly due to strong cooling in the tropical Pacific. This study investigates the possible role of the Indian Ocean warming on the tropical Pacific cooling. Despite the continued rise in sea surface temperature (SST) over the tropical Indian Ocean, SST over the tropical Pacific has shown a cooling trend in the recent decade (2002 - 2012). It is well known fact that the Indian Ocean and the Pacific Ocean are strongly coupled to each other and the Indian Ocean basin wide warming is triggered by El Niño on interannual time scale. However, in the recent decade, this relationship is weakening. The recent Indian Ocean warming is triggering a Matsuno-Gill type response in the atmosphere by generating anomalous cyclonic circulations on either side of equator over the tropical Indian Ocean and anomalous easterlies along the tropical Pacific Ocean. These anomalous easterlies result in Ekman divergence in the equatorial Pacific and produce upwelling Kelvin waves, cools the tropical Pacific and therefore indirectly contributes to the hiatus in global warming.

  4. Trends and drivers in global surface ocean pH over the past three decades

    NASA Astrophysics Data System (ADS)

    Lauvset, S. K.; Gruber, N.; Landschützer, P.; Olsen, A.; Tjiputra, J.

    2014-11-01

    We report global long-term trends in surface ocean pH using a new pH data set computed by combining fCO2 observations from the Surface Ocean CO2 Atlas (SOCAT) version 2 with surface alkalinity estimates based on temperature and salinity. Trends were determined over the periods 1981-2011 and 1991-2011 for a set of 17 biomes using a weighted linear least squares method. We observe significant decreases in surface ocean pH in ~70% of all biomes and a global mean rate of decrease of -0.0018 ± 0.0004 yr-1 for 1991-2011. We are not able to calculate a global trend for 1981-2011 because too few biomes have enough data for this. In two-thirds of the biomes, the rate of change is commensurate with the trends expected based on the assumption that the surface ocean pH change is only driven by the surface ocean carbon chemistry remaining in a transient equilibrium with the increase in atmospheric CO2. In the remaining biomes deviations from such equilibrium may reflect changes in the trend of surface ocean fCO2, most notably in the equatorial Pacific Ocean, or changes in the oceanic buffer (Revelle) factor. We conclude that well-planned and long-term sustained observational networks are key to reliably document the ongoing and future changes in ocean carbon chemistry due to anthropogenic forcing.

  5. The seasonal cycle of diabatic heat storage in the Pacific Ocean

    USGS Publications Warehouse

    White, Warren B.; Cayan, D.R.; Niiler, P.P.; Moisan, J.; Lagerloef, G.; Bonjean, F.; Legler, D.

    2005-01-01

    This study quantifies uncertainties in closing the seasonal cycle of diabatic heat storage (DHS) over the Pacific Ocean from 20??S to 60??N through the synthesis of World Ocean Circulation Experiment (WOCE) reanalysis products from 1993 to 1999. These products are DHS from Scripps Institution of Oceanography (SIO); near-surface geostrophic and Ekman currents from Earth and Space Research (ESR); and air-sea heat fluxes from Comprehensive Ocean-Atmosphere Data Set (COADS), National Centers for Environmental Prediction (NCEP), and European Center for Mid-Range Weather Forecasts (ECMWF). With these products, we compute residual heat budget components by differencing long-term monthly means from the long-term annual mean. This allows the seasonal cycle of the DHS tendency to be modeled. Everywhere latent heat flux residuals dominate sensible heat flux residuals, shortwave heat flux residuals dominate longwave heat flux residuals, and residual Ekman heat advection dominates residual geostrophic heat advection, with residual dissipation significant only in the Kuroshio-Oyashio current extension. The root-mean-square (RMS) of the differences between observed and model residual DHS tendencies (averaged over 10??latitude-by-20??longitude boxes) is <20 W m-2 in the interior ocean and <100 W m-2 in the Kuroshio-Oyashio current extension. This reveals that the residual DHS tendency is driven everywhere by some mix of residual latent heat flux, shortwave heat flux, and Ekman heat advection. Suppressing bias errors in residual air-sea turbulent heat fluxes and Ekman heat advection through minimization of the RMS differences reduces the latter to <10 W m-2 over the interior ocean and <25 W m -2 in the Kuroshio-Oyashio current extension. This reveals air-sea temperature and specific humidity differences from in situ surface marine weather observations to be a principal source of bias error, overestimated over most of ocean but underestimated near the Intertropical Convergence Zone

  6. Global warming: Growing feedback from ocean carbon to climate

    NASA Astrophysics Data System (ADS)

    Joos, Fortunat

    2015-06-01

    The finding that feedbacks between the ocean's carbon cycle and climate may become larger than terrestrial carbon-climate feedbacks has implications for the socio-economic effects of today's fossil-fuel emissions.

  7. Visualization and analysis of eddies in a global ocean simulation

    SciTech Connect

    Williams, Sean J; Hecht, Matthew W; Petersen, Mark; Strelitz, Richard; Maltrud, Mathew E; Ahrens, James P; Hlawitschka, Mario; Hamann, Bernd

    2010-10-15

    Eddies at a scale of approximately one hundred kilometers have been shown to be surprisingly important to understanding large-scale transport of heat and nutrients in the ocean. Due to difficulties in observing the ocean directly, the behavior of eddies below the surface is not very well understood. To fill this gap, we employ a high-resolution simulation of the ocean developed at Los Alamos National Laboratory. Using large-scale parallel visualization and analysis tools, we produce three-dimensional images of ocean eddies, and also generate a census of eddy distribution and shape averaged over multiple simulation time steps, resulting in a world map of eddy characteristics. As expected from observational studies, our census reveals a higher concentration of eddies at the mid-latitudes than the equator. Our analysis further shows that mid-latitude eddies are thicker, within a range of 1000-2000m, while equatorial eddies are less than 100m thick.

  8. Global variability of the wavenumber spectrum of oceanic mesoscale turbulence

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Fu, L.

    2010-12-01

    The wavenumber spectra of sea surface height from the Jason-1 satellite observations have revealed complex spatial variability and significant departure from the predictions of existing theories over many parts of the world oceans. Near the edge of the core regions of high eddy energy, agreement is observed with the prediction of the surface quasi-geostrophic (SQG) turbulence theory which has fundamental differences from that of the traditional quasi-geostrophic (QG) turbulence theory. In the core regions of high eddy energy, the spectra are consistent with frontogenesis that is not fully accounted for by the SQG theory. However, the observations in the vast ocean interior of low eddy energy exhibit substantial differences from the predictions of existing theories of oceanic mesoscale turbulence. The observations presented in this work serve as a test bed for new theories and ocean general circulation models.

  9. Ocean Circulation and its Role in Global Warming

    NASA Astrophysics Data System (ADS)

    Vallis, Geoffrey

    2013-03-01

    The surface of the planet is warming because of increased greenhouse gases in the atmosphere. To predict the rate of increase we need to understand how much heat and carbon dioxide are taken up by the ocean. This in turn requires an understanding of both turbulent processes in the upper ocean and the deep, quasi-laminar, overturning circulation. The timescale for the ocean to fully equilibrate to increased greenhouse gases is likely much longer than the timescale on which fossil fuels will still be readily available, and this has important ramifications for what we mean by climate sensitivity. I will discuss these issues with an emphasis on the physical processes of the ocean.

  10. Sensitivity of global ocean heat content from reanalyses to the atmospheric reanalysis forcing: A comparative study

    NASA Astrophysics Data System (ADS)

    Storto, Andrea; Yang, Chunxue; Masina, Simona

    2016-05-01

    The global ocean heat content evolution is a key component of the Earth's energy budget and can be consistently determined by ocean reanalyses that assimilate hydrographic profiles. This work investigates the impact of the atmospheric reanalysis forcing through a multiforcing ensemble ocean reanalysis, where the ensemble members are forced by five state-of-the-art atmospheric reanalyses during the meteorological satellite era (1979-2013). Data assimilation leads the ensemble to converge toward robust estimates of ocean warming rates and significantly reduces the spread (1.48 ± 0.18 W/m2, per unit area of the World Ocean); hence, the impact of the atmospheric forcing appears only marginal for the global heat content estimates in both upper and deeper oceans. A sensitivity assessment performed through realistic perturbation of the main sources of uncertainty in ocean reanalyses highlights that bias correction and preprocessing of in situ observations represent the most crucial component of the reanalysis, whose perturbation accounts for up to 60% of the ocean heat content anomaly variability in the pre-Argo period. Although these results may depend on the single reanalysis system used, they reveal useful information for the ocean observation community and for the optimal generation of perturbations in ocean ensemble systems.

  11. Energetics of a Global Ocean Circulation Model Compared to Observations

    DTIC Science & Technology

    2011-08-09

    in the dynamics of the ocean circulation with instabilities of the strong mean currents generating eddies in the upper ocean. Interactions between...obser- vations from surface drifters, geostrophic currents from satellite altimetry, subsurface floats and deep current meter moorings. HYCOM...rings of the boundary currents [Stammer, 1997; Ferrari and Wunsch, 2009, 2010], is generated by instabilities of the mean flow and direct wind forcing

  12. Global Bathymetric Prediction For Ocean Modeling and Marine Geophysics

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Smith, Walter H. F.; Sichoix, Lydie; Frey, Herbert V. (Technical Monitor)

    2001-01-01

    We proposed to construct a complete bathymetric map of the oceans at a 3-10 km resolution by combining all of the available depth soundings collected over the past 30 years with high resolution marine gravity information provided by the Geosat, ERS-1/2, and Topex/Poseidon altimeters. Detailed bathymetry is essential for understanding physical oceanography and marine geophysics. Currents and tides are controlled by the overall shapes of the ocean basins as well as the smaller sharp ocean ridges and seamounts. Because erosion rates are low in the deep oceans, detailed bathymetry reveals the mantle convection patterns, the plate boundaries, the cooling/subsidence of the oceanic lithosphere, the oceanic plateaus, and the distribution of off-ridge volcanoes. We proposed to: (1) Accumulate all available depth soundings collected over the past 30 years; (2) Use the short wavelength (< 160 km) satellite gravity information to interpolate between sparse ship soundings; (3) Improve the resolution of the marine gravity field using enhanced estimates along repeat altimeter profiles together with the dense altimeter measurements; (4) Refine/improve bathymetric predictions using the improved resolution gravity field and also by investigating computer-intensive methods for bathymetric prediction such as inverse theory; and (5) Produce a 'Globe of the Earth' similar to the globe of Venus prepared by the NASA Magellan investigation. This will also include the best available digital land data.

  13. Perfluorinated acids as novel chemical tracers of global circulation of ocean waters.

    PubMed

    Yamashita, Nobuyoshi; Taniyasu, Sachi; Petrick, Gert; Wei, Si; Gamo, Toshitaka; Lam, Paul K S; Kannan, Kurunthachalam

    2008-01-01

    Perfluorinated acids (PFAs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are global environmental contaminants. The physicochemical properties of PFAs are unique in that they have high water solubilities despite the low reactivity of carbon-fluorine bond, which also imparts high stability in the environment. Because of the high water solubilities, the open-ocean water column is suggested to be the final sink for PFOS and PFOA. However, little is known on the distribution of PFAs in the oceans around the world. Here we describe the horizontal (spatial) and vertical distribution of PFAs in ocean waters worldwide. PFOS and PFOA concentrations in the North Atlantic Ocean ranged from 8.6 to 36pg l(-1) and from 52 to 338pg l(-1), respectively, whereas the corresponding concentrations in the Mid Atlantic Ocean were 13-73pg l(-1) and 67-439pg l(-1). These were completely different from the surface waters of the South Pacific Ocean and the Indian Ocean (overall range of <5-11pg l(-1) for PFOS and PFOA). Vertical profiles of PFAs in the marine water column were associated with the global ocean circulation theory. Vertical profiles of PFAs in water columns from the Labrador Sea reflected the influx of the North Atlantic Current in surface waters, the Labrador Current in subsurface waters, and the Denmark Strait Overflow Water in deep layers below 2000m. Striking differences in the vertical and spatial distribution of PFAs, depending on the oceans, suggest that these persistent acids can serve as useful chemical tracers to allow us to study oceanic transportation by major water currents. The results provide evidence that PFA concentrations and profiles in the oceans adhere to a pattern consistent with the global "Broecker's Conveyor Belt" theory of open ocean water circulation.

  14. Examination and comparison of SMOS and MyOcean global salinity data

    NASA Astrophysics Data System (ADS)

    Samuel-Rhoads, Yianna; Nikolaidis, Andreas; Zodiatis, George

    2014-05-01

    The recent availability of satellite remote sensing data of ocean salinity from SMOS, has promoted the oceanographic exploitation of these results and their comparison with other available ocean salinity databases, in order to determine the validity and accuracy of the SMOS measurements. Here, we examine monthly global SMOS salinity data for the years 2010 and 2011, and compare them with monthly global data from the project MyOcean during the above timeframe. The MyOcean project aims to deliver and operate a rigorous, robust and sustainable Ocean Monitoring and Forecasting system of the GMES Marine Service (OMF/GMS) to users for all marine applications. SMOS salinity data were obtained from the CP34 SMOS Barcelona Expert Centre (SMOS-BEC) site. Ten-day average satellite ocean salinity reprocessed data were obtained for 2010 and 2011, at 1 degree resolution from the ascending orbit, and averaged into monthly mean values. MyOcean global salinity data were obtained from the L4 reprocessing for 2010 and 2011, at 1/3 degree resolution. These data were then interpolated to 1x1 degree resolution and compared with the SMOS global monthly salinity data. Over the examined months, the SMOS satellite underestimates global salinity values relative to MyOcean, except for three occasions. In January 2010, SMOS overestimates salinity values (+0.112 psu), while for April 2010 (+0.02 psu) as well as for April 2011 (-0.017 psu) the SMOS satellite is recording similar salinity values as the MyOcean data. During September for both years, the highest discrepancy is observed between the two datasets, with the SMOS satellite recording salinities much lower than the MyOcean data (0.43 psu and 0.516 psu difference respectively). On a monthly basis, SMOS satellite records higher than MyOcean salinity values in the Gulf of Mexico, the delta of the Amazon River, off Rio Grande Brazil, as well as off the Antarctic coast (an overestimation possibly associated with the Antarctic Coastal Current

  15. Topex/Poseidon satellite - Enabling a joint U.S.-French mission for global ocean study

    NASA Technical Reports Server (NTRS)

    Hall, Ralph L.

    1990-01-01

    A joint U.S./French mission, which represents a merging of the prior NASA Topex and CNES Poseidon progams, is described. The Topex/Poseidon satellite will contribute to two of the World Climate Research Program's phases: the World Ocean Circulation Experiment and the Tropical Ocean Global Atmosphere experiment. The satellite's instruments will measure the ocean currents and their variability on the global basis via satellite altimetry and precision orbit determinations. The paper describes the satellite configuration and characteristics and the mission instruments and system elements. The Topex/Poseidon's design diagrams and block diagrams are included.

  16. CLIVAR-GSOP/GODAE Ocean Synthesis Inter-Comparison of Global Air-Sea Fluxes From Ocean and Coupled Reanalyses

    NASA Astrophysics Data System (ADS)

    Valdivieso, Maria

    2014-05-01

    The GODAE OceanView and CLIVAR-GSOP ocean synthesis program has been assessing the degree of consistency between global air-sea flux data sets obtained from ocean or coupled reanalyses (Valdivieso et al., 2014). So far, fifteen global air-sea heat flux products obtained from ocean or coupled reanalyses have been examined: seven are from low-resolution ocean reanalyses (BOM PEODAS, ECMWF ORAS4, JMA/MRI MOVEG2, JMA/MRI MOVECORE, Hamburg Univ. GECCO2, JPL ECCOv4, and NCEP GODAS), five are from eddy-permitting ocean reanalyses developed as part of the EU GMES MyOcean program (Mercator GLORYS2v1, Reading Univ. UR025.3, UR025.4, UKMO GloSea5, and CMCC C-GLORS), and the remaining three are couple reanalyses based on coupled climate models (JMA/MRI MOVE-C, GFDL ECDA and NCEP CFSR). The global heat closure in the products over the period 1993-2009 spanned by all data sets is presented in comparison with observational and atmospheric reanalysis estimates. Then, global maps of ensemble spread in the seasonal cycle, and of the Signal to Noise Ratio of interannual flux variability over the 17-yr common period are shown to illustrate the consistency between the products. We have also studied regional variability in the products, particularly at the OceanSITES project locations (such as, for instance, the TAO/TRITON and PIRATA arrays in the Tropical Pacific and Atlantic, respectively). Comparisons are being made with other products such as OAFlux latent and sensible heat fluxes (Yu et al., 2008) combined with ISCCP satellite-based radiation (Zhang et al., 2004), the ship-based NOC2.0 product (Berry and Kent, 2009), the Large and Yeager (2009) hybrid flux dataset CORE.2, and two atmospheric reanalysis products, the ECMWF ERA-Interim reanalysis (referred to as ERAi, Dee et al., 2011) and the NCEP/DOE reanalysis R2 (referred to as NCEP-R2, Kanamitsu et al., 2002). Preliminary comparisons with the observational flux products from OceanSITES are also underway. References Berry, D

  17. Ocean Front Detection from MERIS and OLCI Ocean Colour Data Applied to Marine Conservation and Global Oceanography

    NASA Astrophysics Data System (ADS)

    Miller, Peter I.

    2015-12-01

    Ocean front detection and aggregation techniques were recently applied to 300m resolution Medium Resolution Imaging Spectrometer (MERIS) satellite ocean colour data for the first time, to describe frequently occurring shelf-sea fronts near to the Scottish coast (Miller et al., in press). This resolution enabled the location of smaller frontal zones and those in close proximity to a convoluted coastline, and was used to identify zones of ecological importance that could assist the process of defining marine protected areas. Frequent front zones are associated with higher abundance of plankton, certain pelagic fish and megafauna. This paper anticipates the improved insights into submesoscale sediment and plankton dynamics that will result from application of these techniques to the Ocean and Land Colour Instrument (OLCI) on Sentinel-3a and 3b. Looking to the global scale, we show global chlorophyll-a fronts, eddies and other structures detected from the ESA Ocean Colour Climate Change Initiative daily 4 km resolution merged dataset derived from MERIS, SeaWiFS and MODIS data. This emphasises the importance of the Sentinel missions to improving study of both physical and biological ocean processes.

  18. Can we detect long-term, global change from sparse, 135-year-old ocean data?

    NASA Astrophysics Data System (ADS)

    Hobbs, W. R.; Willis, J. K.

    2012-12-01

    Since almost all the climate system's heat capacity resides in the global ocean, observed long-term changes in ocean heat content (OHC) are invaluable for estimating the planet's radiative imbalance. Several studies produce such estimates from in situ observations, but generally these estimates are restricted to the late 20th century onwards, prior to which there was little global observation. Recent studies have compared modern Argo-based estimates of global ocean temperature with estimates from the 1873-1876 HMS Challenger expedition, the first global-scale survey of the subsurface oceans, and report a significant temperature difference between the Challenger and Argo periods. In this work, using simulations from the CMIP5 suite of earth system model's, we ask firstly whether this temperature difference between two relatively short time periods can be attributed to an anthropogenic warming over the entire global ocean, and secondly how well this difference represents a truly global change. We demonstrate that it is extremely unlikely that the temperature difference along the Challenger cruise track could be caused by natural variability alone. Furthermore, the Challenger data provides a reasonable proxy for the true 135-year global temperature difference.

  19. New features of global climatology revealed by satellite-derived oceanic rainfall maps

    NASA Technical Reports Server (NTRS)

    Rao, M. S. V.; Theon, J. S.

    1977-01-01

    Quantitative rainfall maps over the oceanic areas of the globe were derived from the Nimbus 5 Electrically Scanning Microwave Radiometer (ESMR) data. Analysis of satellite derived oceanic rainfall maps reveal certain distinctive characteristics of global patterns for the years 1973-74. The main ones are (1) the forking of the Intertropical Convergence Zone in the Pacific, (2) a previously unrecognized rain area in the South Atlantic, (3) the bimodal behavior of rainbelts in the Indian Ocean and (4) the large interannual variability in oceanic rainfall. These features are discussed.

  20. The polar oceans and their role in shaping the global environment

    SciTech Connect

    Johannessen, O.M.; Muench, R.D.; Overland, J.E.

    1994-12-31

    This book is a comprehensive treatment of major advances made in the past decade in understanding of the interactions between polar oceans and the local atmosphere and ocean system. Included are 38 papers discussing the circulation, dynamics and convective processes occurring in the polar oceans; its carbon cycle chemistry and biology; the paleooceanography and paleoclimate of the polar regions; the interaction between the polar ocean and the global climate, and a variety of strategies for detection of climate change in polar regions, predominantly Arctic.

  1. Oceanic Carbon Dioxide Uptake in a Model of Century-Scale Global Warming

    PubMed

    Sarmiento; Le Quéré C

    1996-11-22

    In a model of ocean-atmosphere interaction that excluded biological processes, the oceanic uptake of atmospheric carbon dioxide (CO2) was substantially reduced in scenarios involving global warming relative to control scenarios. The primary reason for the reduced uptake was the weakening or collapse of the ocean thermohaline circulation. Such a large reduction in this ocean uptake would have a major impact on the future growth rate of atmospheric CO2. Model simulations that include a simple representation of biological processes show a potentially large offsetting effect resulting from the downward flux of biogenic carbon. However, the magnitude of the offset is difficult to quantify with present knowledge.

  2. How well do global ocean biogeochemistry models simulate dissolved iron distributions?

    NASA Astrophysics Data System (ADS)

    Tagliabue, Alessandro; Aumont, Olivier; DeAth, Ros; Dunne, John P.; Dutkiewicz, Stephanie; Galbraith, Eric; Misumi, Kazuhiro; Moore, J. Keith; Ridgwell, Andy; Sherman, Elliot; Stock, Charles; Vichi, Marcello; Völker, Christoph; Yool, Andrew

    2016-02-01

    Numerical models of ocean biogeochemistry are relied upon to make projections about the impact of climate change on marine resources and test hypotheses regarding the drivers of past changes in climate and ecosystems. In large areas of the ocean, iron availability regulates the functioning of marine ecosystems and hence the ocean carbon cycle. Accordingly, our ability to quantify the drivers and impacts of fluctuations in ocean ecosystems and carbon cycling in space and time relies on first achieving an appropriate representation of the modern marine iron cycle in models. When the iron distributions from 13 global ocean biogeochemistry models are compared against the latest oceanic sections from the GEOTRACES program, we find that all models struggle to reproduce many aspects of the observed spatial patterns. Models that reflect the emerging evidence for multiple iron sources or subtleties of its internal cycling perform much better in capturing observed features than their simpler contemporaries, particularly in the ocean interior. We show that the substantial uncertainty in the input fluxes of iron results in a very wide range of residence times across models, which has implications for the response of ecosystems and global carbon cycling to perturbations. Given this large uncertainty, iron fertilization experiments based on any single current generation model should be interpreted with caution. Improvements to how such models represent iron scavenging and also biological cycling are needed to raise confidence in their projections of global biogeochemical change in the ocean.

  3. Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Le Quéré, C.; Buitenhuis, E. T.; Moriarty, R.; Alvain, S.; Aumont, O.; Bopp, L.; Chollet, S.; Enright, C.; Franklin, D. J.; Geider, R. J.; Harrison, S. P.; Hirst, A.; Larsen, S.; Legendre, L.; Platt, T.; Prentice, I. C.; Rivkin, R. B.; Sathyendranath, S.; Stephens, N.; Vogt, M.; Sailley, S.; Vallina, S. M.

    2015-07-01

    Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs); six types of phytoplankton, three types of zooplankton, and heterotrophic bacteria. We improved the representation of zooplankton dynamics in our model through (a) the explicit inclusion of large, slow-growing zooplankton, and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean High Nutrient Low Chlorophyll (HNLC) region during summer. When model simulations do not represent crustacean macrozooplankton grazing, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when there was no iron deposition from dust. When model simulations included the developments of the zooplankton component, the simulation of phytoplankton biomass improved and the high chlorophyll summer bias in the Southern Ocean HNLC region largely disappeared. Our model results suggest that the observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community rather than iron limitation. This result has implications for the representation of global biogeochemical cycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean.

  4. Pliocene three-dimensional global ocean temperature reconstruction

    USGS Publications Warehouse

    Dowsett, H.J.; Robinson, M.M.; Foley, K.M.

    2009-01-01

    A snapshot of the thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water tempera-5 ture estimates produced using Mg/Ca paleothermometry. This reconstruction assumes a Pliocene water mass framework similar to that which exists today, with several important modifications. The area of formation of present day North Atlantic Deep Water (NADW) was expanded and extended further north toward the Arctic Ocean during the mid-Piacenzian relative to today. This, combined with a deeper Greenland-Scotland Ridge, allowed a greater volume of warmer NADW to enter the Atlantic Ocean. In the Southern Ocean, the Polar Front Zone was expanded relative to present day, but shifted closer to the Antarctic continent. This, combined with at least seasonal reduction in sea ice extent, resulted in decreased Antarctic BottomWater (AABW) production (relative to present day) as well as possible changes in the depth of intermediate wa15 ters. The reconstructed mid-Piacenzian three-dimensional ocean was warmer overall than today, and the hypothesized aerial extent of water masses appears to fit the limited stable isotopic data available for this time period. ?? Author(s) 2009.

  5. Pliocene three-dimensional global ocean temperature reconstruction

    USGS Publications Warehouse

    Dowsett, H.J.; Robinson, M.M.; Foley, K.M.

    2009-01-01

    The thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water temperature estimates from 27 locations produced using Mg/Ca paleothermometry based upon the ostracod genus Krithe. Deep water temperature estimates are skewed toward the Atlantic Basin (63% of the locations) and represent depths from 1000m to 4500 m. This reconstruction, meant to serve as a validation data set as well as an initialization for coupled numerical climate models, assumes a Pliocene water mass framework similar to that which exists today, with several important modifications. The area of formation of present day North Atlantic Deep Water (NADW) was expanded and extended further north toward the Arctic Ocean during the mid-Piacenzian relative to today. This, combined with a deeper Greenland-Scotland Ridge, allowed a greater volume of warmer NADW to enter the Atlantic Ocean. In the Southern Ocean, the Polar Front Zone was expanded relative to present day, but shifted closer to the Antarctic continent. This, combined with at least seasonal reduction in sea ice extent, resulted in decreased Antarctic Bottom Water (AABW) production (relative to present day) as well as possible changes in the depth of intermediate waters. The reconstructed mid-Piacenzian three-dimensional ocean was warmer overall than today, and the hypothesized aerial extent of water masses appears to fit the limited stable isotopic data available for this time period. ?? Author(s) 2009.

  6. The role of clouds and oceans in global greenhouse warming. Part 1, Progress report

    SciTech Connect

    Hoffert, M.I.

    1992-12-01

    During the past three years we have conducted several studies using models and a combination of satellite data, in situ meteorological and oceanic data, and paleoclimate reconstructions, under the DoE program, ``Quantifying the Link Between Change in Radiative Balance and Atmospheric Temperature``. Our goals were to investigate effects of global cloudiness variations on global climate and their implications for cloud feedback and continue development and application of NYU transient climate/ocean models, with emphasis on coupled effects of greenhouse warming and feedbacks by both the clouds and oceans. Our original research plan emphasized the use of cloud, surface temperature and ocean data sets interpreted by focused climate/ocean models to develop a cloud radiative forcing scenario for the past 100 years and to assess the transient climate response; to narrow key uncertainties in the system; and to identify those aspects of the climate system most likely to be affected by greenhouse warming over short, medium and long time scales.

  7. Global Observations and Understanding of the General Circulation of the Oceans

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The workshop was organized to: (1) assess the ability to obtain ocean data on a global scale that could profoundly change our understanding of the circulation; (2) identify the primary and secondary elements needed to conduct a World Ocean Circulation Experiment (WOCE); (3) if the ability is achievable, to determine what the U.S. role in such an experiment should be; and (4) outline the steps necessary to assure that an appropriate program is conducted. The consensus of the workshop was that a World Ocean Circulation Experiment appears feasible, worthwhile, and timely. Participants did agree that such a program should have the overall goal of understanding the general circulation of the global ocean well enough to be able to predict ocean response and feedback to long-term changes in the atmosphere. The overall goal, specific objectives, and recommendations for next steps in planning such an experiment are included.

  8. How well-connected is the surface of the global ocean?

    PubMed

    Froyland, Gary; Stuart, Robyn M; van Sebille, Erik

    2014-09-01

    The Ekman dynamics of the ocean surface circulation is known to contain attracting regions such as the great oceanic gyres and the associated garbage patches. Less well-known are the extents of the basins of attractions of these regions and how strongly attracting they are. Understanding the shape and extent of the basins of attraction sheds light on the question of the strength of connectivity of different regions of the ocean, which helps in understanding the flow of buoyant material like plastic litter. Using short flow time trajectory data from a global ocean model, we create a Markov chain model of the surface ocean dynamics. The surface ocean is not a conservative dynamical system as water in the ocean follows three-dimensional pathways, with upwelling and downwelling in certain regions. Using our Markov chain model, we easily compute net surface upwelling and downwelling, and verify that it matches observed patterns of upwelling and downwelling in the real ocean. We analyze the Markov chain to determine multiple attracting regions. Finally, using an eigenvector approach, we (i) identify the five major ocean garbage patches, (ii) partition the ocean into basins of attraction for each of the garbage patches, and (iii) partition the ocean into regions that demonstrate transient dynamics modulo the attracting garbage patches.

  9. Concentrations and ratios of particulate organic carbon, nitrogen, and phosphorus in the global ocean.

    PubMed

    Martiny, Adam C; Vrugt, Jasper A; Lomas, Michael W

    2014-01-01

    Knowledge of concentrations and elemental ratios of suspended particles are important for understanding many biogeochemical processes in the ocean. These include patterns of phytoplankton nutrient limitation as well as linkages between the cycles of carbon and nitrogen or phosphorus. To further enable studies of ocean biogeochemistry, we here present a global dataset consisting of 100,605 total measurements of particulate organic carbon, nitrogen, or phosphorus analyzed as part of 70 cruises or time-series. The data are globally distributed and represent all major ocean regions as well as different depths in the water column. The global median C:P, N:P, and C:N ratios are 163, 22, and 6.6, respectively, but the data also includes extensive variation between samples from different regions. Thus, this compilation will hopefully assist in a wide range of future studies of ocean elemental ratios.

  10. Concentrations and ratios of particulate organic carbon, nitrogen, and phosphorus in the global ocean

    PubMed Central

    Martiny, Adam C; Vrugt, Jasper A; Lomas, Michael W

    2014-01-01

    Knowledge of concentrations and elemental ratios of suspended particles are important for understanding many biogeochemical processes in the ocean. These include patterns of phytoplankton nutrient limitation as well as linkages between the cycles of carbon and nitrogen or phosphorus. To further enable studies of ocean biogeochemistry, we here present a global dataset consisting of 100,605 total measurements of particulate organic carbon, nitrogen, or phosphorus analyzed as part of 70 cruises or time-series. The data are globally distributed and represent all major ocean regions as well as different depths in the water column. The global median C:P, N:P, and C:N ratios are 163, 22, and 6.6, respectively, but the data also includes extensive variation between samples from different regions. Thus, this compilation will hopefully assist in a wide range of future studies of ocean elemental ratios. PMID:25977799

  11. Century-long trend of global ocean warming identified

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    One of the largest sources of uncertainty in reconstructing the warming of the past century stems from problems with historical ocean temperature records. Inconsistencies in method or technology or gaps in observation caused by two world wars mean that long-term records of sea temperature need to be interpreted with care. Drawing on two historical sets of ocean temperature observations—one of the sea surface and the other of the upper 20 meters—Gouretski et al. found that the twentieth century saw a long-term trend of ocean warming. The two data sets were mostly collected independently, using different tools and techniques, and were subjected to different processing. The authors suggest that, owing to the distinct ways in which the data were gathered, the presence of a similar trend could mean that it is not a spurious finding.

  12. Trends and drivers in global surface ocean pH over the past 3 decades

    NASA Astrophysics Data System (ADS)

    Lauvset, S. K.; Gruber, N.; Landschützer, P.; Olsen, A.; Tjiputra, J.

    2015-03-01

    We report global long-term trends in surface ocean pH using a new pH data set computed by combining fCO2 observations from the Surface Ocean CO2 Atlas (SOCAT) version 2 with surface alkalinity estimates based on temperature and salinity. Trends were determined over the periods 1981-2011 and 1991-2011 for a set of 17 biomes using a weighted linear least squares method. We observe significant decreases in surface ocean pH in ~70% of all biomes and a mean rate of decrease of 0.0018 ± 0.0004 yr-1 for 1991-2011. We are not able to calculate a global trend for 1981-2011 because too few biomes have enough data for this. In half the biomes, the rate of change is commensurate with the trends expected based on the assumption that the surface ocean pH change is only driven by the surface ocean CO2 chemistry remaining in a transient equilibrium with the increase in atmospheric CO2. In the remaining biomes, deviations from such equilibrium may reflect that the trend of surface ocean fCO2 is not equal to that of the atmosphere, most notably in the equatorial Pacific Ocean, or may reflect changes in the oceanic buffer (Revelle) factor. We conclude that well-planned and long-term sustained observational networks are key to reliably document the ongoing and future changes in ocean carbon chemistry due to anthropogenic forcing.

  13. Novel lineages of Prochlorococcus and Synechococcus in the global oceans.

    PubMed

    Huang, Sijun; Wilhelm, Steven W; Harvey, H Rodger; Taylor, Karen; Jiao, Nianzhi; Chen, Feng

    2012-02-01

    Picocyanobacteria represented by Prochlorococcus and Synechococcus have an important role in oceanic carbon fixation and nutrient cycling. In this study, we compared the community composition of picocyanobacteria from diverse marine ecosystems ranging from estuary to open oceans, tropical to polar oceans and surface to deep water, based on the sequences of 16S-23S rRNA internal transcribed spacer (ITS). A total of 1339 ITS sequences recovered from 20 samples unveiled diverse and several previously unknown clades of Prochlorococcus and Synechococcus. Six high-light (HL)-adapted Prochlorococcus clades were identified, among which clade HLVI had not been described previously. Prochlorococcus clades HLIII, HLIV and HLV, detected in the Equatorial Pacific samples, could be related to the HNLC clades recently found in the high-nutrient, low-chlorophyll (HNLC), iron-depleted tropical oceans. At least four novel Synechococcus clades (out of six clades in total) in subcluster 5.3 were found in subtropical open oceans and the South China Sea. A niche partitioning with depth was observed in the Synechococcus subcluster 5.3. Members of Synechococcus subcluster 5.2 were dominant in the high-latitude waters (northern Bering Sea and Chukchi Sea), suggesting a possible cold-adaptation of some marine Synechococcus in this subcluster. A distinct shift of the picocyanobacterial community was observed from the Bering Sea to the Chukchi Sea, which reflected the change of water temperature. Our study demonstrates that oceanic systems contain a large pool of diverse picocyanobacteria, and further suggest that new genotypes or ecotypes of picocyanobacteria will continue to emerge, as microbial consortia are explored with advanced sequencing technology.

  14. Heat Storage in the Deep Ocean as a Capacitor to Explain Deglaciations.

    NASA Astrophysics Data System (ADS)

    Adkins, J. F.; Thiagarajan, N.

    2014-12-01

    Since the classic work of Hays, Imbrie, and Shackleton in 1976, we have known that glacial cycles are paced by the Milankovitch frequencies. However, it has also been long recognized that deglaciations, especially in the '100k-world', are too abrupt to be a linear response of the climate system to this orbital forcing. To explain this 'sawtooth' behavior, rising pCO2 in the atmosphere has been proposed to be an amplifier of deglacial climate change. Yet this CO2 must come from somewhere and it does not seem to be an early responder in the deglacial sequence of events. Most ideas focus on the deep ocean as the only reservoir large enough to store the CO2 on G-I timescales, including the capacity to release it quickly. Here we propose a new 'capacitor' for the climate system, deep ocean heat storage, that could provide the key physical mechanism to explain the important features of deglacial climate. There is a growing body of evidence, from carbonate stable isotopes and pore water salinity estimates, that the Last Glacial Maximum deep ocean was more stratified than today. Through thermobaricity in seawater's equation of state (the pressure dependence of the thermal expansion coefficient), salt stratification can store heat in a water column that is locally statically stable. However, analogous to CAPE in the atmosphere, this heat energy is convectively available and can lead to large, abrupt deep-ocean mixing. Using clumped isotopes in deep-sea corals from Heinrich Event 1, we have found warmer water underneath colder water, about 800 years before the Bolling-Alerod warming recorded in Greenland ice cores. We propose that the abrupt nature of the Bolling is due to the discharge of this deep ocean thermal capacitor which then changes the deep circulation from a glacial to a modern pattern.

  15. Global Shallow-Water Bathymetry from Satellite Ocean Color Data

    DTIC Science & Technology

    2010-11-16

    muiine powei plant planning understanding HI censsstem connect ivm coustul management and change analyses Because ocean .ire.is are enormousl) Lute and...spectral data, satellite altimetry, ocean bathymetry 16. SECURITY CLASSIFICATION OF a REPORT I nclassified b ABSTRACT Unclassified c THIS...tiv.’rtinK.’llirisiiiliimultl • •.sill M . till’ |MII ’i »rilli itil |i - «r •’•’ I llu N.is|tlr.-tt II. .... iutta "" HUB; HHMH s-| -tr.n

  16. A global survey of ocean-atmosphere interaction and climate variability

    NASA Astrophysics Data System (ADS)

    Wang, Chunzai; Xie, Shang-Ping; Carton, James A.

    The interaction of the ocean and atmosphere plays an important role in shaping the climate and its variations. This chapter reviews the current state of knowledge of air-sea interaction and climate variations over the global ocean. The largest source of climate variability in the instrumental record is El Niño—Southern Oscillation (ENSO), which extends its reach globally through the ability of the atmosphere to bridge ocean basins. The growth of ENSO owes its existence to a positive ocean—atmosphere feedback mechanism (originally envisioned by J. Bjerknes) that involves the interaction of ocean dynamics, atmospheric convection, and winds in the equatorial Pacific. The Bjerknes feedback and the resultant equatorial zonal mode of climate variability are a common feature to all three tropical oceans despite differences in dimension, geometry and mean climate. In addition to this zonal mode, the tropics also support a meridional mode, whose growth is due to a thermodynamic feedback mechanism involving the interaction of the cross—equatorial gradient of properties such as sea surface temperature and displacements of the seasonal intertropical convergence zone. This meridional mode is observed in the tropical Atlantic, with some evidence of its existence in the Pacific and Indian Oceans. In the extratropics, in contrast, the sources of climate variability are more distributed. Much of climate variability may be explained by the presence of white noise due to synoptic weather disturbances whose impact on climate at longer timescales is due to the integrating effect of the ocean's ability to store and release heat. Still, there is some evidence of a more active role for the mid—latitude ocean in climate variability, especially near major ocean currents/fronts. Finally, various atmospheric and oceanic bridges that link different ocean basins are discussed, along with their implications for paleoclimate changes and the current global warming.

  17. Uptake and storage of anthropogenic CO2 in the pacific ocean estimated using two modeling approaches

    NASA Astrophysics Data System (ADS)

    Li, Yangchun; Xu, Yongfu

    2012-07-01

    A basin-wide ocean general circulation model (OGCM) of the Pacific Ocean is employed to estimate the uptake and storage of anthropogenic CO2 using two different simulation approaches. The simulation (named BIO) makes use of a carbon model with biological processes and full thermodynamic equations to calculate surface water partial pressure of CO2, whereas the other simulation (named PTB) makes use of a perturbation approach to calculate surface water partial pressure of anthropogenic CO2. The results from the two simulations agree well with the estimates based on observation data in most important aspects of the vertical distribution as well as the total inventory of anthropogenic carbon. The storage of anthropogenic carbon from BIO is closer to the observation-based estimate than that from PTB. The Revelle factor in 1994 obtained in BIO is generally larger than that obtained in PTB in the whole Pacific, except for the subtropical South Pacific. This, to large extent, leads to the difference in the surface anthropogenic CO2 concentration between the two runs. The relative difference in the annual uptake between the two runs is almost constant during the integration processes after 1850. This is probably not caused by dissolved inorganic carbon (DIC), but rather by a factor independent of time. In both runs, the rate of change in anthropogenic CO2 fluxes with time is consistent with the rate of change in the growth rate of atmospheric partial pressure of CO2.

  18. Preliminary Results from Global and Regional Ensemble Ocean Forecasting

    DTIC Science & Technology

    2013-05-01

    Cooper-Haines, 3 used MODAS synthetics. Two used 35 layers instead of 27. Some used an updated version of NCODA and one used mixed layer...depth to modify the MODAS synthetic, etc.) Set 2 (2012): All 3DVar, 32 vs. 41 layers, different ocean analysis configurations 20 SSH

  19. Global diversity and oceanic divergence of humpback whales (Megaptera novaeangliae)

    PubMed Central

    Jackson, Jennifer A.; Steel, Debbie J.; Beerli, P.; Congdon, Bradley C.; Olavarría, Carlos; Leslie, Matthew S.; Pomilla, Cristina; Rosenbaum, Howard; Baker, C. Scott

    2014-01-01

    Humpback whales (Megaptera novaeangliae) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide population history of humpbacks, and the interplay of this species with the oceanic environment through geological time, we assembled mitochondrial DNA control region sequences representing approximately 2700 individuals (465 bp, 219 haplotypes) and eight nuclear intronic sequences representing approximately 70 individuals (3700 bp, 140 alleles) from the North Pacific, North Atlantic and Southern Hemisphere. Bayesian divergence time reconstructions date the origin of humpback mtDNA lineages to the Pleistocene (880 ka, 95% posterior intervals 550–1320 ka) and estimate radiation of current Northern Hemisphere lineages between 50 and 200 ka, indicating colonization of the northern oceans prior to the Last Glacial Maximum. Coalescent analyses reveal restricted gene flow between ocean basins, with long-term migration rates (individual migrants per generation) of less than 3.3 for mtDNA and less than 2 for nuclear genomic DNA. Genetic evidence suggests that humpbacks in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae to three subspecies. PMID:24850919

  20. Global diversity and oceanic divergence of humpback whales (Megaptera novaeangliae).

    PubMed

    Jackson, Jennifer A; Steel, Debbie J; Beerli, P; Congdon, Bradley C; Olavarría, Carlos; Leslie, Matthew S; Pomilla, Cristina; Rosenbaum, Howard; Baker, C Scott

    2014-07-07

    Humpback whales (Megaptera novaeangliae) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide population history of humpbacks, and the interplay of this species with the oceanic environment through geological time, we assembled mitochondrial DNA control region sequences representing approximately 2700 individuals (465 bp, 219 haplotypes) and eight nuclear intronic sequences representing approximately 70 individuals (3700 bp, 140 alleles) from the North Pacific, North Atlantic and Southern Hemisphere. Bayesian divergence time reconstructions date the origin of humpback mtDNA lineages to the Pleistocene (880 ka, 95% posterior intervals 550-1320 ka) and estimate radiation of current Northern Hemisphere lineages between 50 and 200 ka, indicating colonization of the northern oceans prior to the Last Glacial Maximum. Coalescent analyses reveal restricted gene flow between ocean basins, with long-term migration rates (individual migrants per generation) of less than 3.3 for mtDNA and less than 2 for nuclear genomic DNA. Genetic evidence suggests that humpbacks in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae to three subspecies. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. The Ocean of Truth: A Personal History of Global Tectonics

    NASA Astrophysics Data System (ADS)

    Frankel, Henry

    H. W. Menard died on February 9, 1986. His professional legacy includes much of his scientific work in unearthing the floor of the Pacific Ocean, his former students, and his work in the history of science. In addition to his earlier endeavor into the history and sociology of science, Science Growth and Change (Harvard University Press, Cambridge, Mass., 1971), Menard leaves us The Ocean of Truth. Unable to stop himself from doing research, he corrected the galley proofs for The Ocean of Truth during the last days of his life, in his hospital bed, while dying of cancer. I include Menard's work in the history of science within his professional legacy, since Menard did not approach the history of science as a retired scientist who decides to write, with memory as his only guide, about his and his fellow scientists' research. The Ocean of Truth is a serious and successful attempt to recount the rise of oceanography and its bearing upon the recent revolution in the Earth sciences.

  2. Accuracy assessment of the global ionospheric model over the Southern Ocean based on dynamic observation

    NASA Astrophysics Data System (ADS)

    Luo, Xiaowen; Xu, Huajun; Li, Zishen; Zhang, Tao; Gao, Jinyao; Shen, Zhongyan; Yang, Chunguo; Wu, Ziyin

    2017-02-01

    The global ionospheric model based on the reference stations of the Global Navigation Satellite System (GNSS) of the International GNSS Services is presently the most commonly used products of the global ionosphere. It is very important to comprehensively analyze and evaluate the accuracy and reliability of the model for the reasonable use of this kind of ionospheric product. In terms of receiver station deployment, this work is different from the traditional performance evaluation of the global ionosphere model based on observation data of ground-based static reference stations. The preliminary evaluation and analysis of the the global ionospheric model was conducted with the dynamic observation data across different latitudes over the southern oceans. The validation results showed that the accuracy of the global ionospheric model over the southern oceans is about 5 TECu, which deviates from the measured ionospheric TEC by about -0.6 TECu.

  3. The Global Ocean Data Analysis Project version 2 (GLODAPv2) - an internally consistent data product for the world ocean

    NASA Astrophysics Data System (ADS)

    Olsen, Are; Key, Robert M.; van Heuven, Steven; Lauvset, Siv K.; Velo, Anton; Lin, Xiaohua; Schirnick, Carsten; Kozyr, Alex; Tanhua, Toste; Hoppema, Mario; Jutterström, Sara; Steinfeldt, Reiner; Jeansson, Emil; Ishii, Masao; Pérez, Fiz F.; Suzuki, Toru

    2016-08-01

    Version 2 of the Global Ocean Data Analysis Project (GLODAPv2) data product is composed of data from 724 scientific cruises covering the global ocean. It includes data assembled during the previous efforts GLODAPv1.1 (Global Ocean Data Analysis Project version 1.1) in 2004, CARINA (CARbon IN the Atlantic) in 2009/2010, and PACIFICA (PACIFic ocean Interior CArbon) in 2013, as well as data from an additional 168 cruises. Data for 12 core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have been subjected to extensive quality control, including systematic evaluation of bias. The data are available in two formats: (i) as submitted but updated to WOCE exchange format and (ii) as a merged and internally consistent data product. In the latter, adjustments have been applied to remove significant biases, respecting occurrences of any known or likely time trends or variations. Adjustments applied by previous efforts were re-evaluated. Hence, GLODAPv2 is not a simple merging of previous products with some new data added but a unique, internally consistent data product. This compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µmol kg-1 in dissolved inorganic carbon, 6 µmol kg-1 in total alkalinity, 0.005 in pH, and 5 % for the halogenated transient tracers.The original data and their documentation and doi codes are available at the Carbon Dioxide Information Analysis Center (oceans/GLODAPv2/" target="_blank">http://cdiac.ornl.gov/oceans/GLODAPv2/). This site also provides access to the calibrated data product, which is provided as a single global file or four regional ones - the Arctic, Atlantic, Indian, and Pacific oceans - under the doi:10.3334/CDIAC

  4. U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model

    DTIC Science & Technology

    2008-09-30

    comparison in relation to the present state of the art (Bryan et al., 2007; Chassignet and Marshall, 2008), with the model pathway paralleling the...Modular Ocean Data Assimilation System ( MODAS ). These profiles are only created where the satellite based SSH anomalies with respect to the previous...day’s ocean analysis exceed a user-defined value. Error analyses of the same unassimilated T & S profile observations using the MODAS approach yielded

  5. US GODAE: Global Ocean Prediction with the Hybrid Coordinate Ocean Model (HYCOM)

    DTIC Science & Technology

    2009-06-01

    coastal application was to assess the impact of open boundary conditions from the HYCOM ocean prediction system on the dynamics and accuracy of a...near the Florida Keys when hurricane Katrina crossed South Florida in late August 2005. iMPact In summary, 25 institutions (nine from academia, nine...example, detailed surface current information derived from HYCOM is summarized by OCENS (Ocean and Coastal ENviromental Sensing, http

  6. U.S. GODAE: Global Ocean Prediction With the HYbrid Coordinate Ocean Model (HYCOM)

    DTIC Science & Technology

    2009-06-01

    and ocean prediction system developers. The main goal of the first coastal application was to assess the impact of open boundary conditions from...Keys when hurricane Katrina crossed South Florida in late August 2005. IMPACT In summary, 25 institutions (nine from academia, nine from...Ocean and Coastal ENviromental Sensing, http://www.ocens.com) for their customers who continually provide posi- tive feedback on their accuracy

  7. How well will the Surface Water and Ocean Topography (SWOT) mission observe global reservoirs?

    NASA Astrophysics Data System (ADS)

    Solander, Kurt C.; Reager, John T.; Famiglietti, James S.

    2016-03-01

    Accurate observations of global reservoir storage are critical to understand the availability of managed water resources. By enabling estimates of surface water area and height for reservoir sizes exceeding 250 m2 at a maximum repeat orbit of up to 21 days, the NASA Surface Water and Ocean Topography (SWOT) satellite mission (anticipated launch date 2020) is expected to greatly improve upon existing reservoir monitoring capabilities. It is thus essential that spatial and temporal measurement uncertainty for water bodies is known a priori to maximize the utility of SWOT observations as the data are acquired. In this study, we evaluate SWOT reservoir observations using a three-pronged approach that assesses temporal aliasing, errors due to specific reservoir spatial properties, and SWOT performance over actual reservoirs using a combination of in situ and simulated reservoir observations from the SWOTsim instrument simulator. Results indicate temporal errors to be less than 5% for the smallest reservoir sizes (< 10 km2) with errors less than 0.1% for larger sizes (>100 km2). Surface area and height errors were found to be minimal (area <5%, height <15 cm) above 1 km2 unless the reservoir exhibited a strong elliptical shape with high aspect ratio oriented parallel to orbit, was set in mountainous terrain, or swath coverage fell below 30%. Experiments from six real reservoir test cases generally support these results. By providing a comprehensive blueprint on the observability of reservoirs from SWOT, this study will be have important implications for future applications of SWOT reservoir measurements in global monitoring systems and models.

  8. Global storage and distribution trends: Harnessing growth and fighting downturns

    SciTech Connect

    Rossler, W.K.

    1997-05-01

    The storage and distribution sector continues to increase services and value-added benefits to its customers to retain longterm commitment. Unfortunately, few of these services are compensated in terms of increased revenue. To maintain volume and a stable, strong customer base, the terminal operator has no option but to continue to provide these additional services even though this erodes profitability. It`s expected that supply/distribution customers will continue to require environmental health and safety audits, demand faster information and constantly assess whether outsourcing to the storage/distribution company is as good or better than their inhouse systems. Consolidation is likely to continue within the industry into the hands of fewer, larger companies. With the increased personnel and skill levels required to profitably operate storage facilities, smaller, stand-alone facilities will be at a competitive disadvantage. Today, supply/distribution companies recognize that customers face more choices and are more knowledgeable of those choices than in the past and can change loyalties in an instant. However, as a collective lot, supply/distribution companies tend toward a more entrepreneurial bent with a {open_quotes}can do{close_quotes} attitude to continually meet customer expectations with more innovative ideas and cost-effective operations.

  9. Global root zone storage capacity from satellite-based evaporation data

    NASA Astrophysics Data System (ADS)

    Wang-Erlandsson, Lan; Bastiaanssen, Wim; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel; van Dijk, Albert; Guerschman, Juan; Keys, Patrick; Gordon, Line; Savenije, Hubert

    2016-04-01

    We present an "earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale-independent. In contrast to traditional look-up table approaches, our method captures the variability in root zone storage capacity within land cover type, including in rainforests where direct measurements of root depth otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. We find that evergreen forests are able to create a large storage to buffer for extreme droughts (with a return period of up to 60 years), in contrast to short vegetation and crops (which seem to adapt to a drought return period of about 2 years). The presented method to estimate root zone storage capacity eliminates the need for soils and rooting depth information, which could be a game-changer in global land surface modelling.

  10. Probing Io's putative global magma ocean through FUV auroral spot morphology

    NASA Astrophysics Data System (ADS)

    Roth, Lorenz

    2013-10-01

    Whether Io possesses a magma ocean or not is a central issue for understanding the most volcanically active body in our solar system and is a long standing question as well. Khurana et al., Science 2011, recently substantiated the existence of a highly conductive magma layer inside Io's interior based on Galileo magnetometer measurements and techniques similar to those used to probe the crusts of Europa, Ganymede, and Callisto for liquid water oceans. If a global magma ocean modifies Io's local magnetic field environment, it will also significantly alter the morphology of Io's UV aurora. The most prominent aurora features are two bright spots that rock around the equator roughly in correlation with the varying orientation of the tilted Jovian magnetic field. Magnetic induction in a magma ocean would strongly attenuate the rocking of these near-surface spots. Interestingly, in previous STIS FUV observations the measured spot locations disagree considerably from the locations theoretically predicted for the global magma ocean case, but are in reasonable agreement if there is no ocean. However, the temporal and orbital coverage of Io's rocking auroral spots for the STIS dataset is presently insufficient to conclusively exclude or further investigate the molten magma layer idea. We therefore propose two visits of five consecutive STIS orbits to trend the auroral spot feature locations over a full variation cycle of the Jovian magnetic field near western elongation. This investigation will decisively constrain the molten magma layer inside Io and tests the putative evidence for a global ocean by Khurana et al. {2011}.

  11. Development of a global ocean mercury model with a methylation cycle: Outstanding issues

    NASA Astrophysics Data System (ADS)

    Semeniuk, Kirill; Dastoor, Ashu

    2017-02-01

    We present a newly developed global ocean mercury (Hg) transport and biogeochemistry model and use preanthropogenic equilibrium simulations to highlight physical and chemical processes which reveal significant knowledge gaps that need to be addressed. As with previous 3-D ocean Hg model work we use a bulk chemistry scheme based on particulate organic carbon remineralization. We also include an explicit methylation cycle based on available reaction rates. The methylation to demethylation rate ratio based on various field studies is found to be inconsistent with the concentration ratios measured in the Southern Ocean around Antarctica and in the Arctic. There is also model-measurement disagreement in the old waters of the tropical and North Pacific Ocean. The model produces an intermediate water maximum in total Hg in this region reflecting the higher age of water which is absent in observations. The model also underestimates total Hg concentrations in the deepest waters in this region. These disagreements in depth profile shape point to an inadequate representation of scavenging and sedimentation and possibly seabed emission or remobilization of Hg. In addition, the total Hg distribution differences compared to previous model work reflect sensitivity to ocean model transport characteristics and in particular the tracer diffusion. The residence time of Hg in the global ocean and the surface evasion flux of elemental Hg is sensitive to such model aspects. We find a global ocean Hg turnover time against sediment burial to be about 1100 years which is within the range of previous studies.

  12. Global phylogeography of marine Synechococcus and Prochlorococcus reveals a distinct partitioning of lineages among oceanic biomes.

    PubMed

    Zwirglmaier, Katrin; Jardillier, Ludwig; Ostrowski, Martin; Mazard, Sophie; Garczarek, Laurence; Vaulot, Daniel; Not, Fabrice; Massana, Ramon; Ulloa, Osvaldo; Scanlan, Dave J

    2008-01-01

    Marine cyanobacteria of the genera Prochlorococcus and Synechococcus are important contributors to global primary production occupying a key position at the base of marine food webs. The genetically diverse nature of each genus is likely an important reason for their successful colonization of vast tracts of the world's oceans, a feature that has led to detailed analysis of the distribution of these genetic lineages at the local and ocean basin scale. Here, we extend these analyses to the global dimension, using new data from cruises in the Pacific, Indian and Arctic Oceans in combination with data from previous studies in the Atlantic Ocean, Arabian Sea, Red Sea and a circumnavigation of the southern hemisphere to form a data set which comprises most of the world's major ocean systems. We show that the distribution patterns of Prochlorococcus and Synechococcus lineages are remarkably similar in different ocean systems with comparable environmental conditions, but producing a strikingly different 'signature' in the four major ocean domains or biomes (the Polar Domain, Coastal Boundary Domain, Trade Winds Domain and Westerly Winds Domain). This clearly reiterates the idea of spatial partitioning of individual cyanobacterial lineages, but at the global scale.

  13. Effects of process conditions on chlorine generation and storage stability of electrolyzed deep ocean water.

    PubMed

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. We investigated the effects of platinum plating of electrode, electrode size, cell potential, and additional stirring on electrolysis properties of deep ocean water (DOW) and DOW concentration products. We also studied the relationships between quality properties of electrolyzed DOW and their storage stability. Results indicated that concentrating DOW to 1.7 times increased chlorine level in the electrolyzed DOW without affecting electric and current efficiencies of the electrolysis process. Increasing magnesium and potassium levels in DOW decreased chlorine level in the electrolyzed DOW as well as electric and current efficiencies of the electrolysis process. Additional stirring could not increase electrolysis efficiency of small electrolyzer. Large electrode, high electric potential and/or small electrolyzing cell increased chlorine production rate but decreased electric and current efficiencies. High electrolysis intensity decreased storage stability of the electrolyzed seawater and the effects of electrolysis on DOW gradually subsided in storage. DOW has similar electrolysis properties to surface seawater, but its purity and stability are better. Therefore, electrolyzed DOW should have better potential for applications on postharvest cleaning and disinfection of ready-to-eat fresh produce. Copyright © 2015. Published by Elsevier B.V.

  14. The Contribution of Reservoirs to Global Land Surface Water Storage Variations

    SciTech Connect

    Zhou, Tian; Nijssen, Bart; Gao, Huilin; Lettenmaier, Dennis P.

    2016-12-21

    Man-made reservoirs play a key role in the terrestrial water system. They alter water fluxes at the land surface and impact surface water storage through water management regulations for diverse purposes such as irrigation, municipal water supply, hydropower generation, and flood control. Although most developed countries have established sophisticated observing systems for many variables in the land surface water cycle, long-term and consistent records of reservoir storage are much more limited and not always shared. Furthermore, most land surface hydrological models do not represent the effects of water management activities. Here, the contribution of reservoirs to seasonal water storage variations is investigated using a large-scale water management model to simulate the effects of reservoir management at basin and continental scales. The model was run from 1948 to 2010 at a spatial resolution of 0.258 latitude–longitude. A total of 166 of the largest reservoirs in the world with a total capacity of about 3900 km3 (nearly 60%of the globally integrated reservoir capacity) were simulated. The global reservoir storage time series reflects the massive expansion of global reservoir capacity; over 30 000 reservoirs have been constructed during the past half century, with a mean absolute interannual storage variation of 89 km3. The results indicate that the average reservoir-induced seasonal storage variation is nearly 700 km3 or about 10%of the global reservoir storage. For some river basins, such as the Yellow River, seasonal reservoir storage variations can be as large as 72%of combined snow water equivalent and soil moisture storage.

  15. Assessment of storage lipid accumulation patterns in eucalanoid copepods from the eastern tropical Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Cass, Christine J.; Daly, Kendra L.; Wakeham, Stuart G.

    2014-11-01

    Members of the copepod family Eucalanidae are widely distributed throughout the world's oceans and have been noted for their accumulation of storage lipids in high- and low-latitude environments. However, little is known about the lipid composition of eucalanoid copepods in low-latitude environments. The purpose of this study was to examine fatty acid and alcohol profiles in the storage lipids (wax esters and triacylglycerols) of Eucalanus inermis, Rhincalanus rostrifrons, R. nasutus, Pareucalanus attenuatus, and Subeucalanus subtenuis, collected primarily in the eastern tropical north Pacific near the Tehuantepec Bowl and Costa Rica Dome regions, noted for its oxygen minimum zone, during fall 2007 and winter 2008/2009. Adult copepods and particulate material were collected in the upper 50 m and from 200 to 300 m in the upper oxycline. Lipid profiles of particulate matter were generated to help ascertain information on ecological strategies of these species and on differential accumulation of dietary and modified fatty acids in the wax ester and triacylglycerol storage lipid components of these copepods in relation to their vertical distributions around the oxygen minimum zone. Additional data on phospholipid fatty acid and sterol/fatty alcohol fractions were also generated to obtain a comprehensive lipid data set for each sample. Rhincalanus spp. accumulated relatively large amounts of storage lipids (31-80% of dry mass (DM)), while E. inermis had moderate amounts (2-9% DM), and P. attenuatus and S. subtenuis had low quantities of storage lipid (0-1% DM). E. inermis and S. subtenuis primarily accumulated triacylglycerols (>90% of storage lipids), while P. attenuatus and Rhincalanus spp. primarily accumulated wax esters (>84% of storage lipids). Based on previously generated molecular phylogenies of the Eucalanidae family, these results appear to support genetic predisposition as a major factor explaining why a given species accumulates primarily triacylglycerols

  16. A 3D parameterization of iron atmospheric deposition to the global ocean

    NASA Astrophysics Data System (ADS)

    Myriokefalitakis, Stelios; Krol, Maarten C.; van Noije, Twan P. C.; Le Sager, Philippe

    2017-04-01

    Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients to the global ocean, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Iron (Fe) is a key micronutrient that significantly modulates gross primary production in High-Nutrient-Low-Chlorophyll (HNLC) oceans, where macronutrients like nitrate are abundant but primary production is limited by Fe scarcity. The global atmospheric Fe cycle is here parameterized in the state-of-the-art global Earth System Model EC-Earth. The model takes into account the primary emissions of both insoluble and soluble Fe, associated with dusts and combustion processes. The impact of atmospheric acidity on mineral solubility is parameterized based on updated experimental and theoretical findings, and model results are evaluated against available observations. The link between the soluble Fe atmospheric deposition and anthropogenic sources is also investigated. Overall, the response of the chemical composition of nutrient containing aerosols to atmospheric composition changes is demonstrated and quantified. This work has been financed by the Marie-Curie H2020-MSCA-IF-2015 grant (ID 705652) ODEON (Online DEposition over OceaNs: Modeling the effect of air pollution on ocean bio-geochemistry in an Earth System Model).

  17. Phenological Responses to ENSO in the Global Oceans

    NASA Astrophysics Data System (ADS)

    Racault, M.-F.; Sathyendranath, S.; Menon, N.; Platt, T.

    2017-01-01

    Phenology relates to the study of timing of periodic events in the life cycle of plants or animals as influenced by environmental conditions and climatic forcing. Phenological metrics provide information essential to quantify variations in the life cycle of these organisms. The metrics also allow us to estimate the speed at which living organisms respond to environmental changes. At the surface of the oceans, microscopic plant cells, so-called phytoplankton, grow and sometimes form blooms, with concentrations reaching up to 100 million cells per litre and extending over many square kilometres. These blooms can have a huge collective impact on ocean colour, because they contain chlorophyll and other auxiliary pigments, making them visible from space. Phytoplankton populations have a high turnover rate and can respond within hours to days to environmental perturbations. This makes them ideal indicators to study the first-level biological response to environmental changes. In the Earth's climate system, the El Niño-Southern Oscillation (ENSO) dominates large-scale inter-annual variations in environmental conditions. It serves as a natural experiment to study and understand how phytoplankton in the ocean (and hence the organisms at higher trophic levels) respond to climate variability. Here, the ENSO influence on phytoplankton is estimated through variations in chlorophyll concentration, primary production and timings of initiation, peak, termination and duration of the growing period. The phenological variabilities are used to characterise phytoplankton responses to changes in some physical variables: sea surface temperature, sea surface height and wind. It is reported that in oceanic regions experiencing high annual variations in the solar cycle, such as in high latitudes, the influence of ENSO may be readily measured using annual mean anomalies of physical variables. In contrast, in oceanic regions where ENSO modulates a climate system characterised by a seasonal

  18. Sea level ECV quality assessment via global ocean model assimilation

    NASA Astrophysics Data System (ADS)

    Scharffenberg, Martin; Köhl, Armin; Stammer, Detlef

    2015-04-01

    In the ocean modeling community satellite data, especially SSH fields, are assimilated on a regular basis. SSH fields are very important in this context because of their dynamical relevance for constraining the ocean's flow field. However, assimilating SSH data into an ocean model does not only improve the quality of model but in addition, can also help testing the quality and the consistency of the input data as well. In our work we aim to quantify improvements in Sea Level (SL) data through the ESA - Climate Change Initiative (cci) effort and we aim to test the consistency of the Essential Climate Variable (ECV) of Sea Level (SL_ECV) with other ECVs through the assimilation process and to investigate where remaining inconsistencies exist and why. For this purpose the GECCO2 assimilation approach assimilates SSH jointly with in situ data over the ocean. The dynamically consistent ocean state estimation adjusts only uncertain model parameters to bring the model into consistency with ocean observations. Improvements in data products can be investigated by studying the residuals between the different data products and the constrained model. PHASE 1: With this approach we could demonstrate, that in many regions the SL_ECV has been improved from version V0 (AVISO product) to version V1 (SL_cci product). However, there are regions where SL_ECV_V1 is further away from the model "truth". In that sense it is important to understand that the model assimilated SL_ECV_V0 (origianl AVISO product) and therefore has tried to adapt to the SL_ECV_V0. Therefore, inconsistencies existed when comparing the synthesis results to the updated version SL_ECV_V1! These deviations between the model "truth" and the improved data product (SL_ECV_V1) increased mostly in low energetic areas. PHASE 2: Two GECCO2-assimilation-runs (5 additional iterations) have been performed to date: 1) assimilating the original AVISO SL-product (V0) and 2) assimilating the updated-improved sea level estimate

  19. Global Ocean Circulation Modeling with an Isopycnic Coordinate Model. Final Report for May 1, 1998 - April 30, 2002

    SciTech Connect

    Bleck, R.

    2004-05-19

    The overall aim of this project was to continue development of a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM) with the intent of turning it into a full-fledged oceanic component of an earth system model.

  20. Seasonal Distributions of Global Ocean Chlorophyll and Nutrients: Analysis with a Coupled Ocean General Circulation Biogeochemical, and Radiative Model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.

    1999-01-01

    A coupled general ocean circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. The model is driven by climatological meteorological conditions, cloud cover, and sea surface temperature. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chorophytes, and picoplankton) and three nutrient groups (nitrate, ammonium, and silicate). Phytoplankton groups are initialized as homogeneous fields horizontally and vertically, and allowed to distribute themselves according to the prevailing conditions. Basin-scale model chlorophyll results are in very good agreement with CZCS pigments in virtually every global region. Seasonal variability observed in the CZCS is also well represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are also in good conformance, although occasional departures are apparent. Agreement of nitrate distributions with in situ data is even better, including seasonal dynamics, except for the equatorial Atlantic. The good agreement of the model with satellite and in situ data sources indicates that the model dynamics realistically simulate phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization, and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent the great diversity of physical, biological

  1. Global variations in gravity-derived oceanic crustal thickness: Implications on oceanic crustal accretion and hotspot-lithosphere interactions

    NASA Astrophysics Data System (ADS)

    Lin, J.; Zhu, J.

    2012-12-01

    We present a new global model of oceanic crustal thickness based on inversion of global oceanic gravity anomaly with constrains from seismic crustal thickness profiles. We first removed from the observed marine free-air gravity anomaly all gravitational effects that can be estimated and removed using independent constraints, including the effects of seafloor topography, marine sediment thickness, and the age-dependent thermal structure of the oceanic lithosphere. We then calculated models of gravity-derived crustal thickness through inversion of the residual mantle Bouguer anomaly using best-fitting gravity-modeling parameters obtained from comparison with seismically determined crustal thickness profiles. Modeling results show that about 5% of the global crustal volume (or 9% of the global oceanic surface area) is associated with model crustal thickness <5.2 km (designated as "thin" crust), while 56% of the crustal volume (or 65% of the surface area) is associated with crustal thickness of 5.2-8.6 km thick (designated as "normal" crust). The remaining 39% of the crustal volume (or 26% of the surface area) is associated with crustal thickness >8.6 km and is interpreted to have been affected by excess magmatism. The percentage of oceanic crustal volume that is associated with thick crustal thickness (>8.6 km) varies greatly among tectonic plates: Pacific (33%), Africa (50%), Antarctic (33%), Australia (30%), South America (34%), Nazca (23%), North America (47%), India (74%), Eurasia (68%), Cocos (20%), Philippine (26%), Scotia (41%), Caribbean (89%), Arabian (82%), and Juan de Fuca (21%). We also found that distribution of thickened oceanic crust (>8.6 km) seems to depend on spreading rate and lithospheric age: (1) On ocean basins younger than 5 Ma, regions of thickened crust are predominantly associated with slow and ultraslow spreading ridges. The relatively strong lithospheric plate at slow and ultraslow ridges might facilitate the loading of large magmatic

  2. Global Upper Ocean Heat Content and Climate Variability

    DTIC Science & Technology

    2011-01-01

    References Ashok K, Behera S, Rao A. S, Weng H., and Yamagata, T., 2007. El Nino Modoki and...2027–2033. Rao, S. A., S. K. Behera , Y. Masumoto, and T. Yamagata, 2002. Interannual subsurface variability in the tropical Indian Ocean with a...W., 1937. World weather VI. Mem. Roy. Meteor. Soc., 4, 119–139. Weng, H., Ashok, S. K., Behera , S., . Rao, A., Yamagata, T., 2007

  3. Total Human-Caused Global Ocean Heat Uptake Nearly Doubles During Recent Surface Warming Hiatus

    NASA Astrophysics Data System (ADS)

    Gleckler, P. J.; Durack, P. J.; Stouffer, R. J.; Johnson, G. C.; Forest, C. E.

    2015-12-01

    Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0­-700 m) ocean. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes evidenced in observational, modelling, and data re-analysis studies. We rely on OHC change estimates from a diverse collection of measurement systems including data from the 19th Century Challenger expedition, a multi-decadal record of ship-based in-situ mostly upper ocean measurements, the more recent near-global Argo floats profiling to intermediate (2000m) depths, and full-depth repeated transoceanic sections. By diagnosing simulated global OHC changes in historically-forced climate models in three depth layers, we show that the current generation of climate models is broadly consistent with multi-decadal estimates of upper, intermediate (700­-2000m) and deep (2000m - ­bottom) global OHC changes as well as with Argo-based estimates over the most recent period. Our results suggest that nearly half of the 1860-­present human-caused increases in global ocean heat content may have occurred since 1998.

  4. Global ocean tide mapping using TOPEX/Poseidon altimetry

    NASA Technical Reports Server (NTRS)

    Sanchez, Braulio V.; Cartwright, D. E.; Estes, R. H.; Williamson, R. G.; Colombo, O. L.

    1991-01-01

    The investigation's main goals are to produce accurate tidal maps of the main diurnal, semidiurnal, and long-period tidal components in the world's deep oceans. This will be done by the application of statistical estimation techniques to long time series of altimeter data provided by the TOPEX/POSEIDON mission, with additional information provided by satellite tracking data. In the prelaunch phase, we will use in our simulations and preliminary work data supplied by previous oceanographic missions, such as Seasat and Geosat. These results will be of scientific interest in themselves. The investigation will also be concerned with the estimation of new values, and their uncertainties, for tidal currents and for the physical parameters appearing in the Laplace tidal equations, such as bottom friction coefficients and eddy viscosity coefficients. This will be done by incorporating the altimetry-derived charts of vertical tides as boundary conditions in the integration of those equations. The methodology of the tidal representation will include the use of appropriate series expansions such as ocean-basin normal modes and spherical harmonics. The results of the investigation will be space-determined tidal models of coverage and accuracy superior to that of the present numerical models of the ocean tides, with the concomitant benefits to oceanography and associated disciplinary fields.

  5. Lipid consumption in coral larvae differs among sites: a consideration of environmental history in a global ocean change scenario.

    PubMed

    Rivest, Emily B; Chen, Chii-Shiarng; Fan, Tung-Yung; Li, Hsing-Hui; Hofmann, Gretchen E

    2017-04-26

    The success of early life-history stages is an environmentally sensitive bottleneck for many marine invertebrates. Responses of larvae to environmental stress may vary due to differences in maternal investment of energy stores and acclimatization/adaptation of a population to local environmental conditions. In this study, we compared two populations from sites with different environmental regimes (Moorea and Taiwan). We assessed the responses of Pocillopora damicornis larvae to two future co-occurring environmental stressors: elevated temperature and ocean acidification. Larvae from Taiwan were more sensitive to temperature, producing fewer energy-storage lipids under high temperature. In general, planulae in Moorea and Taiwan responded similarly to pCO2 Additionally, corals in the study sites with different environments produced larvae with different initial traits, which may have shaped the different physiological responses observed. Notably, under ambient conditions, planulae in Taiwan increased their stores of wax ester and triacylglycerol in general over the first 24 h of their dispersal, whereas planulae from Moorea consumed energy-storage lipids in all cases. Comparisons of physiological responses of P. damicornis larvae to conditions of ocean acidification and warming between sites across the species' biogeographic range illuminates the variety of physiological responses maintained within P. damicornis, which may enhance the overall persistence of this species in the light of global climate change. © 2017 The Author(s).

  6. The Argo Project: Global Ocean Observations for Understanding and Prediction of Climate Variability. Report for Calendar Year 2005

    DTIC Science & Technology

    2005-01-01

    environment of ocean ecosystems. Over 90% of the increased heat content due to global warming of the air/sea/ice climate system in the past 40...years occurred in the oceans. Climate stresses on ocean ecosystems have serious consequences, and sometimes dramatic ones, such as coral reef bleaching ...The Argo Project Global Ocean Observations for Understanding and Prediction of Climate Variability Report for Calendar Year 2005 Dean H

  7. Digital Global Map of Potential Ocean Paleoshorelines on Mars

    NASA Astrophysics Data System (ADS)

    Parker, T. J.; Calef, F. J.

    2012-05-01

    Our objective is to compile a global shoreline map, in the form of GIS shapefiles. This map will be used to investigate deviations from horizontal that might indicate neotectonic changes such as mass accumulations and crustal deformations over time.

  8. Ocean disposal option for bulk wastes containing naturally occurring radionuclides: an assessment case history. [From Niagara Falls storage site

    SciTech Connect

    Stull, E.A.; Merry-Libby, P.

    1985-01-01

    There are 180,000 m/sup 3/ of slightly contaminated radioactive wastes (36 pCi/g radium-226) currently stored at the US Department of Energy's Niagara Falls Storage Site (NFSS), near Lewiston, New York. These wastes resulted from the cleanup of soils that were contaminated above the guidelines for unrestricted use of property. An alternative to long-term management of these wastes on land is dispersal in the ocean. A scenario for ocean disposal is present

  9. A new remote sensing technique to measure global reservoir storage

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-10-01

    Nearly 60% of the world's large rivers are affected by dams, with more than 33,000 large dams holding back upward of 8300 cubic kilometers of water across the planet. Reservoirs are employed worldwide, helping to ensure regular access to fresh water, mitigate flash flooding, and maintain minimum river flow levels. However, not all reservoirs have adequate and accessible monitoring systems. Having no easily accessible method with which to monitor changing reservoir storage volumes hinders long-term planning and efforts to model the Earth's climate.

  10. An index to assess the health and benefits of the global ocean.

    PubMed

    Halpern, Benjamin S; Longo, Catherine; Hardy, Darren; McLeod, Karen L; Samhouri, Jameal F; Katona, Steven K; Kleisner, Kristin; Lester, Sarah E; O'Leary, Jennifer; Ranelletti, Marla; Rosenberg, Andrew A; Scarborough, Courtney; Selig, Elizabeth R; Best, Benjamin D; Brumbaugh, Daniel R; Chapin, F Stuart; Crowder, Larry B; Daly, Kendra L; Doney, Scott C; Elfes, Cristiane; Fogarty, Michael J; Gaines, Steven D; Jacobsen, Kelsey I; Karrer, Leah Bunce; Leslie, Heather M; Neeley, Elizabeth; Pauly, Daniel; Polasky, Stephen; Ris, Bud; St Martin, Kevin; Stone, Gregory S; Sumaila, U Rashid; Zeller, Dirk

    2012-08-30

    The ocean plays a critical role in supporting human well-being, from providing food, livelihoods and recreational opportunities to regulating the global climate. Sustainable management aimed at maintaining the flow of a broad range of benefits from the ocean requires a comprehensive and quantitative method to measure and monitor the health of coupled human–ocean systems. We created an index comprising ten diverse public goals for a healthy coupled human–ocean system and calculated the index for every coastal country. Globally, the overall index score was 60 out of 100 (range 36–86), with developed countries generally performing better than developing countries, but with notable exceptions. Only 5% of countries scored higher than 70, whereas 32% scored lower than 50. The index provides a powerful tool to raise public awareness, direct resource management, improve policy and prioritize scientific research.

  11. MJO simulation in a cloud-system-resolving global ocean-atmosphere coupled model

    NASA Astrophysics Data System (ADS)

    Sasaki, Wataru; Onishi, Ryo; Fuchigami, Hiromitsu; Goto, Koji; Nishikawa, Shiro; Ishikawa, Yoichi; Takahashi, Keiko

    2016-09-01

    An observed Madden-Julian Oscillation (MJO) propagating from the central Indian Ocean to the western Pacific from 15 December 2006 to 10 January 2007 was successfully simulated by a cloud-system-resolving global ocean-atmosphere coupled model without parameterization of cumulus convection. We found that the ocean coupling has significant impacts on the MJO simulation, e.g., strength of the moisture convergence, and the timing and strength of the westerly wind burst over the Maritime Continent. The model also generally well simulated the decay of the MJO in the western Pacific, as well as the changes in sea surface temperature. These results demonstrate that the cloud-system-resolving global ocean-atmosphere coupled model can be used for realistic MJO simulation.

  12. Scientific quality of Mercator Ocean global analyses and forecast in 2016

    NASA Astrophysics Data System (ADS)

    Desportes, Charles; Levier, Bruno; Régnier, Charly; Drévillon, Marie; Perruche, Coralie; Lellouche, Jean-Michel; Legalloudec, Olivier; Clavier, Mathieu

    2017-04-01

    In the framework of the Copernicus Marine Environment Monitoring Service CMEMS, Mercator Ocean provides weekly analyses and daily updated 10-day forecasts of the global physical ocean at high resolution (1/12° horizontal grid, hourly outputs at the surface). Mercator Ocean also disseminates weekly updated estimates of the biogeochemical state of the ocean. The scientific quality of the products is controlled daily, and changes are monitored with a well-defined series of metrics, at the monthly, quarterly and yearly frequencies. This monitoring, also applied systematically to new versions of the production systems, allows to assess the strengths and weaknesses of the systems, and to quantify the improvements of new versions before the entry into service. This poster will display the results of the scientific qualification of Mercator Ocean's ocean analyses and forecast over the year 2016: error will be quantified for the physical ocean, sea ice and biogeochemical variables, at the scale of oceanic basins. Some major ocean large scale signals happening during year 2016 will be highlighted.

  13. Ectomycorrhizal fungi increase soil carbon storage: molecular signatures of mycorrhizal competition driving soil C storage at global scale

    NASA Astrophysics Data System (ADS)

    Averill, C.; Barry, B. K.; Hawkes, C.

    2015-12-01

    Soil carbon storage and decay is regulated by the activity of free-living decomposer microbes, which can be limited by nitrogen availability. Many plants associate with symbiotic ectomycorrhizal fungi on their roots, which produce nitrogen-degrading enzymes and may be able to compete with free-living decomposers for soil organic nitrogen. By doing so, ectomycorrhizal fungi may able to induce nitrogen limitation and reduce activity of free-living microbial decomposition by mining soil organic nitrogen. The implication is that ectomycorrhizal-dominated systems should have increased soil carbon storage relative to non-ectomycorrhizal systems, which has been confirmed at a global scale. To investigate these effects, we analyzed 364 globally distributed observations of soil fungal communities using 454 sequencing of the ITS region, along with soil C and N concentrations, climate and chemical data. We assigned operational taxonomic units using the QIIME pipeline and UNITE fungal database and assigned fungal reads as ectomycorrhizal or non-mycorrhizal based on current taxonomic knowledge. We tested for associations between ectomycorrhizal abundance, climate, and soil carbon and nitrogen. Sites with greater soil carbon had quantitatively more ectomycorrhizal fungi within the soil microbial community based on fungal sequence abundance, after accounting for soil nitrogen availability. This is consistent with our hypothesis that ectomycorrhizal fungi induce nitrogen-limitation of free-living decomposers and thereby increase soil carbon storage. The strength of the mycorrhizal effect increased non-linearly with ectomycorrhizal abundance: the greater the abundance, the greater the effect size. Mean annual temperature, potential evapotranspiration, soil moisture and soil pH were also significant predictors in the final AIC selected model. This analysis suggests that molecular data on soil microbial communities can be used to make quantitative biogeochemical predictions. The

  14. Changes of the Oceanic Long-term and seasonal variation in a Global-warming Climate

    NASA Astrophysics Data System (ADS)

    Xia, Q.; He, Y.; Dong, C.

    2015-12-01

    Abstract: Gridded absolute dynamic topography (ADT) from AVISO and outputs of sea surface height above geoid from a series of climate models run for CMIP5 are used to analysis global sea level variation. Variance has been calculated to determine the magnitude of change in sea level variation over two decades. Increasing trend of variance of ADT suggests an enhanced fluctuation as well as geostrophic shear of global ocean. To further determine on what scale does the increasing fluctuation dominate, the global absolute dynamic topography (ADT) has been separated into two distinguished parts: the global five-year mean sea surface (MSS) and the residual absolute dynamic topography (RADT). Increased variance of MSS can be ascribed to the nonuniform rising of global sea level and an enhancement of ocean gyres in the Pacific Ocean. While trend in the variance of RADT is found to be close to zero which suggests an unchanged ocean mesoscale variability. The Gaussian-like distribution of global ADT are used to study the change in extreme sea levels. Information entropy has also been adapted in our study. Increasing trend of information entropy which measures the degree of dispersion of a probability distribution suggests more appearance of extreme sea levels. Extreme high sea levels are increasing with a higher growing rate than the mean sea level rise.

  15. Cycling of DDT in the global environment 1950-2002: World ocean returns the pollutant

    NASA Astrophysics Data System (ADS)

    Stemmler, Irene; Lammel, Gerhard

    2009-12-01

    The global distribution and fate of the insecticide DDT was modeled for the first time using a spatially resolved global multicompartment chemistry-transport model comprising a 3D coupled atmosphere and ocean GCM, coupled to 2D vegetation surfaces and top soils. DDT enters the model environment as a pesticide in agriculture only. Final sinks of DDT in the total environment are degradation in air (hydroxyl radical reaction), on vegetation surfaces, in ocean sediments and soils. The process resolution of the ocean compartment, i.e., either a fixed or variable size and sinking velocity of suspended particles, has almost no effect on the large-scale cycling and fate of DDT. The residence times in various ocean basins were declining but varied regionally. The global ocean absorbed until 1977 and since then has been losing DDT, while large sea areas are still accumulating the pollutant. The main sink is volatilization to the atmosphere. In 1990, the year when emissions ceased, 292 kt of DDT were deposited to the global ocean, 301 kt were volatilized, and 41 kt were exported from the surface layer to the deeper levels. The sea region that has been representing the most significant (secondary) DDT source is the western N Atlantic (Gulf stream and N Atlantic Drift regions). It has been a source since approximately 1970. Also large parts of the tropical ocean and the southern mid-latitude ocean have turned net volatilizational (i.e., volatilization flux > deposition flux) during the 1980s. Despite the emissions migrating southward as a consequence of substance ban in mid latitudes, the geographic distribution of the contaminant (and, hence, environmental exposure) has been migrating steadily northward since the 1960s.

  16. Assessment of Global Forecast Ocean Assimilation Model (FOAM) using new satellite SST data

    NASA Astrophysics Data System (ADS)

    Ascione Kenov, Isabella; Sykes, Peter; Fiedler, Emma; McConnell, Niall; Ryan, Andrew; Maksymczuk, Jan

    2016-04-01

    There is an increased demand for accurate ocean weather information for applications in the field of marine safety and navigation, water quality, offshore commercial operations, monitoring of oil spills and pollutants, among others. The Met Office, UK, provides ocean forecasts to customers from governmental, commercial and ecological sectors using the Global Forecast Ocean Assimilation Model (FOAM), an operational modelling system which covers the global ocean and runs daily, using the NEMO (Nucleus for European Modelling of the Ocean) ocean model with horizontal resolution of 1/4° and 75 vertical levels. The system assimilates salinity and temperature profiles, sea surface temperature (SST), sea surface height (SSH), and sea ice concentration observations on a daily basis. In this study, the FOAM system is updated to assimilate Advanced Microwave Scanning Radiometer 2 (AMSR2) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI) SST data. Model results from one month trials are assessed against observations using verification tools which provide a quantitative description of model performance and error, based on statistical metrics, including mean error, root mean square error (RMSE), correlation coefficient, and Taylor diagrams. A series of hindcast experiments is used to run the FOAM system with AMSR2 and SEVIRI SST data, using a control run for comparison. Results show that all trials perform well on the global ocean and that largest SST mean errors were found in the Southern hemisphere. The geographic distribution of the model error for SST and temperature profiles are discussed using statistical metrics evaluated over sub-regions of the global ocean.

  17. Mapping the Global Ocean Eddy Field Using a Wide Swath Altimeter

    NASA Astrophysics Data System (ADS)

    Fu, L.; Ferrari, R.

    2008-12-01

    Satellite altimetry has revolutionized observational oceanography in the last decade providing for the first time global observations of the height of sea surface for studying global ocean circulation. The French AVISO data center has produced the most impressive compilation of sea surface height to date, merging measurements from two different altimeters. The data set offers an unprecedented view of the global ocean circulation and its variability. However the intrinsic resolution of the altimetric data, about 200 km in wavelength, is still too coarse to fully resolve the bulk of the ocean kinetic energy which resides in boundary currents and mesoscale eddies with scales of 50-200 km. Along-track altimeter observations do provide higher spatial resolution in one-dimension, but they are dominated by measurement noise at wavelengths shorter than about 100 km. Recent modeling studies suggest that the circulation of the upper ocean in the 10-500 km is well described by the surface quasi-geostrophic (SQG) dynamics. Spectral analysis of altimeter data at wavelengths from 100-300 km corroborates the model results. SQG theory shows that the 3- dimensional velocity field of the upper ocean can be estimated from sea surface height. Recent theoretical work suggests that a major portion of the vertical transport of heat and carbon in the upper ocean takes place at these small scales. The technique of radar interferometry, demonstrated by the Shuttle Radar Topography Mission for mapping the world's land topography, offers a viable approach for mapping ocean surface topography in two dimensions at a spatial resolution of 10-20 kilometers over a finite swath. The prospects of developing a satellite mission using this technique for studying the global ocean eddy field will be presented.

  18. Recent changes of global ocean transparency observed by SeaWiFS

    NASA Astrophysics Data System (ADS)

    He, Xianqiang; Pan, Delu; Bai, Yan; Wang, Tianyu; Chen, Chen-Tung Arthur; Zhu, Qiankun; Hao, Zengzhou; Gong, Fang

    2017-07-01

    The water transparency usually quantized by the Secchi Disk depth, is a key index of water quality, and influences light penetration for phytoplankton photosynthesis. Although in situ measurements have provided century-long datasets in different regions, the seasonal and interannual variations as well as the long-term changes of ocean transparency at the global scale are still poorly understood. In the present study, based on the semi-analytic algorithm, the time series of the monthly global ocean transparency over Sept. 1997 to Nov. 2010 were retrieved from the satellite data observed by the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS). The seasonal and interannual variations of global ocean transparency were identified from the SeaWiFS-derived water transparency. Large seasonal variation amplitude occurred at the front zones between subtropical gyres and high latitude oceans. Moreover, ocean transparency increased in the Northern Hemisphere, while it decreased in the Southern Hemisphere, especially in the Southern Ocean from Sept. 1997 to Nov. 2010. The global mean ocean transparency decreased rapidly with a rate of -0.85 m yr-1 (p=0.001) between 1997 and 1999, followed by a small increase with a rate of 0.04 m yr-1 (p=0.05) over 2000-2010, which might be linked to changes of sea surface temperature with rapid decrease over 1998-1999 and slight increase over 2000-2010. These changes of water transparency may alter the available light for phytoplankton photosynthesis, and influence the thermal evolution of the upper ocean.

  19. Episodic memory in transient global amnesia: encoding, storage, or retrieval deficit?

    PubMed Central

    Eustache, F.; Desgranges, B.; Laville, P.; Guillery, B.; Lalevee, C.; Schaeffer, S.; de la Sayette, V.; Iglesias, S.; Baron, J.; Viader, F.

    1999-01-01

    OBJECTIVES—To assess episodic memory (especially anterograde amnesia) during the acute phase of transient global amnesia to differentiate an encoding, a storage, or a retrieval deficit.
METHODS—In three patients, whose amnestic episode fulfilled all current criteria for transient global amnesia, a neuropsychological protocol was administered which included a word learning task derived from the Grober and Buschke's procedure.
RESULTS—In one patient, the results suggested an encoding deficit, and in two others, a storage deficit.
CONCLUSIONS—The encoding/storage impairment concerning anterograde amnesia documented in our patients stands in clear contrast with the impairment in retrieval which must underly the retrograde amnesia that also characterises transient global amnesia. This dissociation in turn favours the idea of a functional independence among the cognitive mechanisms that subserve episodic memory.

 PMID:10071092

  20. Impacts on the Hydrological Cycle of Counteracting Global Warming with Albedo Changes over Oceans or Land

    NASA Astrophysics Data System (ADS)

    Bala, G.; Caldeira, K.; Nemani, R. R.; Cao, L.; Ban-Weiss, G. A.; Shin, H.

    2010-12-01

    Solar Radiation Management (SRM) "geoengineering" proposals to completely offset global mean temperature increases by reducing the amount of absorbed sunlight nearly uniformly over land and oceans (e.g. stratospheric injection of aerosols) are expected to slow the global water cycle and reduce runoff over land. However, proposed countering of global warming by increasing the albedo of marine clouds or painting the roof white would reduce surface solar radiation either over the oceans or land. Here, we analyze the response of temperature and the hydrological cycle to either increased reflection over the oceans or decreased reflection over land using an atmospheric general circulation model coupled to a mixed layer ocean model. When cloud droplets are reduced in size over all oceans uniformly to offset the temperature increase from a doubling of atmospheric CO2, the global-mean precipitation and evaporation decreases by about 1.3% but runoff over land increases by 7.5% primarily due to increases over tropical land. In the model, more reflective marine clouds cool the atmospheric column over ocean. The result is a sinking motion over oceans and upward motion over land. We attribute the increased runoff over land to this increased upward motion over land when marine clouds are made more reflective. Qualitatively similar results are obtained when reflection from land areas is reduced indicating that increased reflection from land surface could result in reduced precipitation and runoff over land. Our results suggest that offsetting mean global warming by reducing marine cloud droplet size will lead to wetter continents, and large scale increase in land surface albedo could lead to drying of the continents.

  1. Efficient computation of past global ocean circulation patterns using continuation in paleobathymetry

    NASA Astrophysics Data System (ADS)

    Mulder, T. E.; Baatsen, M. L. J.; Wubs, F. W.; Dijkstra, H. A.

    2017-07-01

    In the field of paleoceanographic modeling, the different positioning of Earth's continental configurations is often a major challenge for obtaining equilibrium ocean flow solutions. In this paper, we introduce numerical parameter continuation techniques to compute equilibrium solutions of ocean flows in the geological past, where we change the continental geometry and allow the flow to deform using a homotopy parameter. The methods are illustrated by computing equilibrium three-dimensional global ocean circulation patterns over the last 65 Ma under a highly idealized atmospheric forcing. These results already show interesting major transitions in ocean circulation patterns due to changes in ocean gateways, that may have been relevant for Cenozoic climate transitions. In addition, the techniques are shown to be computationally efficient compared to the established continuation spin-up approach.

  2. Assessment of great ocean currents as a source of renewable energy using recent OGCM simulations of the global ocean

    NASA Astrophysics Data System (ADS)

    Barnier, Bernard; Domina, Anastasiia; Maitre, Thierry; Molines, Jean-Marc; Penduff, Thierry; Le Sommer, Julien; Brasseur, Pierre; Gulev, Sergey

    2017-04-01

    The great wind-driven ocean currents (e.g. Gulf-Stream or Kuroshio) are relatively constant in strength and direction, and they carry a great deal of energy because of the density of water. Technologies are being developed to extract energy from those currents and convert it into a usable power. The paper presents a methodology used to select regions of the global ocean where the properties of the great ocean currents are favourable to the implementation of Turbine Power Plants (TPP) made of submerged rotors driven by the motion of water. The methodology relies on a state-of-the-art eddy-resolving global ocean general circulation model used for real-time ocean forecasting, in which the implementation of a large TPP is represented by an additional drag force applied locally. This system is able to simulate the flow changes induced by the implementation of a power plant in the current, and consequently provides an assessment of the renewable energy that could be recovered and of the possible environmental impact. Our results demonstrate that the flow changes induced by a large TPP (covering the area of a model grid size, i.e. a few km) are highly dependent on the details of local topography, leading to a reduction of the available power that can vary from 25% to 85% according to location. We shall also show that impact of a TPP on the flow can be felt a few 100 kilometres upstream and may in some cases not only impact the flow speed, but also induce a large shift of the main current path.

  3. The global pattern of trace-element distributions in ocean floor basalts.

    PubMed

    O'Neill, Hugh St C; Jenner, Frances E

    2012-11-29

    The magmatic layers of the oceanic crust are created at constructive plate margins by partial melting of the mantle as it wells up. The chemistry of ocean floor basalts, the most accessible product of this magmatism, is studied for the insights it yields into the compositional heterogeneity of the mantle and its thermal structure. However, before eruption, parental magma compositions are modified at crustal pressures by a process that has usually been assumed to be fractional crystallization. Here we show that the global distributions of trace elements in ocean floor basalts describe a systematic pattern that cannot be explained by simple fractional crystallization alone, but is due to cycling of magma through the global ensemble of magma chambers. Variability in both major and incompatible trace-element contents about the average global pattern is due to fluctuations in the magma fluxes into and out of the chambers, and their depth, as well as to differences in the composition of the parental magmas.

  4. Remote sensing of oceanic biology in relation to global climate change

    SciTech Connect

    Aiken, J.; Moore, G.F.; Holligan, P.M. )

    1992-10-01

    The oceans have a fundamental role in the global climate system because of their capacity to store and transport heat and absorb and emit trace gases which affect the earth's radiation budget. Although good progress has been made with issues such as carbon and sulfur cycling, feedback responses related to the impact of climate change on biological systems, and links between plankton ecology and climate, there is a lack of information on the distributions of biological properties on a global scale. This article reviews the potential contribution of ocean color measurements for biological studies within the context of climate change. The remote sensing of oceanic phytoplankton from satellites measuring radiance at visible and near infrared wavelenghts has produced a wealth of new information on biomass distributions and has provided a basis for new approaches to estimation of global marine primary productivity.

  5. The role of clouds and oceans in global greenhouse warming. Final report

    SciTech Connect

    Hoffert, M.I.

    1996-10-01

    This research focuses on assessing connections between anthropogenic greenhouse gas emissions and global climatic change. it has been supported since the early 1990s in part by the DOE ``Quantitative Links`` Program (QLP). A three-year effort was originally proposed to the QLP to investigate effects f global cloudiness on global climate and its implications for cloud feedback; and to continue the development and application of climate/ocean models, with emphasis on coupled effects of greenhouse warming and feedbacks by clouds and oceans. It is well-known that cloud and ocean processes are major sources of uncertainty in the ability to predict climatic change from humankind`s greenhouse gas and aerosol emissions. And it has always been the objective to develop timely and useful analytical tools for addressing real world policy issues stemming from anthropogenic climate change.

  6. A Global, Multi-Resolution Approach to Regional Ocean Modeling

    SciTech Connect

    Du, Qiang

    2013-11-08

    In this collaborative research project between Pennsylvania State University, Colorado State University and Florida State University, we mainly focused on developing multi-resolution algorithms which are suitable to regional ocean modeling. We developed hybrid implicit and explicit adaptive multirate time integration method to solve systems of time-dependent equations that present two signi cantly di erent scales. We studied the e ects of spatial simplicial meshes on the stability and the conditioning of fully discrete approximations. We also studies adaptive nite element method (AFEM) based upon the Centroidal Voronoi Tessellation (CVT) and superconvergent gradient recovery. Some of these techniques are now being used by geoscientists(such as those at LANL).

  7. Global representation of tropical cyclone-induced short-term ocean thermal changes using Argo data

    NASA Astrophysics Data System (ADS)

    Cheng, L.; Zhu, J.; Sriver, R. L.

    2015-09-01

    Argo floats are used to examine tropical cyclone (TC) induced ocean thermal changes on the global scale by comparing temperature profiles before and after TC passage. We present a footprint method that analyzes cross-track thermal responses along all storm tracks during the period 2004-2012. We combine the results into composite representations of the vertical structure of the average thermal response for two different categories: tropical storms/tropical depressions (TS/TD) and hurricanes. The two footprint composites are functions of three variables: cross-track distance, water depth and time relative to TC passage. We find that this footprint strategy captures the major features of the upper-ocean thermal response to TCs on timescales up to 20 days when compared against previous case study results using in situ measurements. On the global scale, TCs are responsible for 1.87 PW (11.05 W m-2) of heat transfer annually from the global ocean to the atmosphere during storm passage (0-3 days). Of this total, 1.05 ± 0.20 PW (4.80 ± 0.85 W m-2) is caused by TS/TD and 0.82 ± 0.21 PW (6.25 ± 1.5 W m-2) is caused by hurricanes. Our findings indicate that ocean heat loss by TCs may be a substantial missing piece of the global ocean heat budget. Changes in ocean heat content (OHC) after storm passage are estimated by analyzing the temperature anomalies during wake recovery following storm events (4-20 days after storm passage) relative to pre-storm conditions. Results indicate the global ocean experiences a 0.75 ± 0.25 PW (5.98 ± 2.1 W m-2) heat gain annually for hurricanes. In contrast, under TS/TD conditions, the ocean experiences 0.41 ± 0.21 PW (1.90 ± 0.96 W m-2) ocean heat loss, suggesting the overall oceanic thermal response is particularly sensitive to the intensity of the event. The ocean heat uptake caused by all storms during the restorative stage is 0.34 PW.

  8. The Tara Oceans voyage reveals global diversity and distribution patterns of marine planktonic ciliates

    PubMed Central

    Gimmler, Anna; Korn, Ralf; de Vargas, Colomban; Audic, Stéphane; Stoeck, Thorsten

    2016-01-01

    Illumina reads of the SSU-rDNA-V9 region obtained from the circumglobal Tara Oceans expedition allow the investigation of protistan plankton diversity patterns on a global scale. We analyzed 6,137,350 V9-amplicons from ocean surface waters and the deep chlorophyll maximum, which were taxonomically assigned to the phylum Ciliophora. For open ocean samples global planktonic ciliate diversity is relatively low (ca. 1,300 observed and predicted ciliate OTUs). We found that 17% of all detected ciliate OTUs occurred in all oceanic regions under study. On average, local ciliate OTU richness represented 27% of the global ciliate OTU richness, indicating that a large proportion of ciliates is widely distributed. Yet, more than half of these OTUs shared <90% sequence similarity with reference sequences of described ciliates. While alpha-diversity measures (richness and exp(Shannon H)) are hardly affected by contemporary environmental conditions, species (OTU) turnover and community similarity (β-diversity) across taxonomic groups showed strong correlation to environmental parameters. Logistic regression models predicted significant correlations between the occurrence of specific ciliate genera and individual nutrients, the oceanic carbonate system and temperature. Planktonic ciliates displayed distinct vertical distributions relative to chlorophyll a. In contrast, the Tara Oceans dataset did not reveal any evidence that latitude is structuring ciliate communities. PMID:27633177

  9. Earth's energy imbalance and the global warming `hiatus': insights from climate models and ocean reanalyses

    NASA Astrophysics Data System (ADS)

    Palmer, M. D.; Roberts, C. D.; McNeall, D. J.

    2016-02-01

    Earth's energy imbalance is the most fundamental metric defining the rate of global climate change. Using CMIP5 climate model simulations, we show that trends in surface temperature are only weakly indicative of the net energy imbalance on decadal timescales, due to the ocean's ability to re-arrange large quantities of heat on these timescales. Therefore, the apparent `hiatus' in global surface temperature rise may tell us nothing about the rate of global climate change over the recent past. CMIP5 models suggest that the ocean becomes dominant term in Earth's energy budget at timescales longer than about 1 year, illustrating the need to improve estimates of the rate-of-change of ocean heat content (OHC) in order to better monitor ongoing anthropogenic climate change. An intercomparison of OHC changes in an ensemble of ocean reanalyses shows some robust signals in the upper few hundred metres but little agreement for deeper layers. This work highlights the need to maintain the Argo observations of the upper 2000m and extend the ocean observing array into the deep and abyssal ocean in order to better monitor and understand variability and long-term changes in Earth's energy imbalance.

  10. Global Patterns of Diatom Diversity Derived from the Tara Oceans Expedition

    NASA Astrophysics Data System (ADS)

    Bowler, C.; Malviya, S.; de Vargas, C.; Audic, S.; Zingone, A.; Scalco, E.; Iudicone, D.; Vincent, F.; Bittner, L.; Wincker, P.; Poulain, J.

    2016-02-01

    Diatoms are believed to be the most important group of photosynthetic eukaryotes in the oceans. Understanding patterns of diatom distribution is therefore important for understanding marine ecosystem functioning. From the Tara Oceans global sampling expedition a total of ca. 14.5 million V9-rRNA ribotypes assigned to diatoms derived from 47 sampling stations that span the global ocean euphotic zone are being analyzed to understand diatom community composition. The dataset contains 65,000 unique ribotypes, present in a wide range of abundances, and represents approximately 3,300 Operational Taxonomic Units. Some of these localize to specific areas such as the Southern Ocean or to sites of diatom blooms, or display interesting biogeographical patterns such as commonalities along the Agulhas current originating from the southwest Indian Ocean. The data also reveal an unexpectedly high level of diatom diversity in the open ocean. Clustering with environmental parameters further reveals correlations of some diatom groups with net primary production and carbon flux. Global comparisons of diatom co-occurrence and exclusion patterns with ribotypes from other organisms provide insights into the interactions of diatoms with other planktonic organisms.

  11. The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally consistent data product for the world ocean

    SciTech Connect

    Olsen, Are; Key, Robert M.; van Heuven, Steven; Lauvset, Siv K.; Velo, Anton; Lin, Xiaohua; Schirnick, Carsten; Kozyr, Alex; Tanhua, Toste; Hoppema, Mario; Jutterström, Sara; Steinfeldt, Reiner; Jeansson, Emil; Ishii, Masao; Pérez, Fiz F.; Suzuki, Toru

    2016-08-15

    Version 2 of the Global Ocean Data Analysis Project (GLODAPv2) data product is composed of data from 724 scientific cruises covering the global ocean. It includes data assembled during the previous efforts GLODAPv1.1 (Global Ocean Data Analysis Project version 1.1) in 2004, CARINA (CARbon IN the Atlantic) in 2009/2010, and PACIFICA (PACIFic ocean Interior CArbon) in 2013, as well as data from an additional 168 cruises. Data for 12 core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have been subjected to extensive quality control, including systematic evaluation of bias. The data are available in two formats: (i) as submitted but updated to WOCE exchange format and (ii) as a merged and internally consistent data product. In the latter, adjustments have been applied to remove significant biases, respecting occurrences of any known or likely time trends or variations. Adjustments applied by previous efforts were re-evaluated. Hence, GLODAPv2 is not a simple merging of previous products with some new data added but a unique, internally consistent data product. In conclusion, this compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µmol kg-1 in dissolved inorganic carbon, 6 µmol kg-1 in total alkalinity, 0.005 in pH, and 5 % for the halogenated transient tracers.

  12. The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally consistent data product for the world ocean

    DOE PAGES

    Olsen, Are; Key, Robert M.; van Heuven, Steven; ...

    2016-08-15

    Version 2 of the Global Ocean Data Analysis Project (GLODAPv2) data product is composed of data from 724 scientific cruises covering the global ocean. It includes data assembled during the previous efforts GLODAPv1.1 (Global Ocean Data Analysis Project version 1.1) in 2004, CARINA (CARbon IN the Atlantic) in 2009/2010, and PACIFICA (PACIFic ocean Interior CArbon) in 2013, as well as data from an additional 168 cruises. Data for 12 core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have been subjected to extensive quality control, including systematic evaluation of bias. Themore » data are available in two formats: (i) as submitted but updated to WOCE exchange format and (ii) as a merged and internally consistent data product. In the latter, adjustments have been applied to remove significant biases, respecting occurrences of any known or likely time trends or variations. Adjustments applied by previous efforts were re-evaluated. Hence, GLODAPv2 is not a simple merging of previous products with some new data added but a unique, internally consistent data product. In conclusion, this compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µmol kg-1 in dissolved inorganic carbon, 6 µmol kg-1 in total alkalinity, 0.005 in pH, and 5 % for the halogenated transient tracers.« less

  13. Contemporary changes and links between salinity and the global ocean water cycle

    NASA Astrophysics Data System (ADS)

    Vinogradova, N. T.; Ponte, R. M.

    2016-12-01

    To understand the ongoing alteration of the Earth's water budget, it is essential to assess the variability of its oceanic constituent as this component supplies more than 75% of the evaporated and precipitated water in the global water cycle. Here we examine the change in the ocean water cycle and the ocean's response to such changes over the contemporary, well-observed period spanning the last two decades. In particular, we focus on recent changes in surface salinity and fluxes of freshwater within the atmosphere-ocean-land-ice system. Using a combination of historical observations and data-constrained ocean estimates we demonstrate that there have been persistent changes (defined as significant trends) in both salinity and the ocean water cycle in many ocean regions, including the subtropical gyres in both hemispheres, low latitudes of the tropical Pacific, the North Atlantic subpolar gyre and the Arctic Ocean. On average, the ocean water cycle has amplified by 5% since 1993, but strong regional variations exist, e.g., up to 11% intensification in the South Pacific contrasting with pattern weakening of -7% in the North Atlantic. An even larger spread in regional variations of the pattern amplification is visible in surface salinity records, ranging between +50% in the Southern Ocean to -40% in the North Atlantic, averaging to less than 1% over the globe. These findings imply a time of emergence of anthropogenic hydrological signals shorter in surface freshwater fluxes than in surface salinity, and point to the importance of ocean circulation and salt transports in shaping patterns of decadal change in surface salinity. The latter is discussed within a closed budget framework by examining the balance between the atmospheric freshwater fluxes and the ocean salt fluxes in regions of salinity extremes, such as salinity maxima in the subtropical gyres and salinity minima in the tropics and high latitudes.

  14. Low-frequency variability of sea level as related to the heat balance of global oceans

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Niiler, P.; Patzert, W.

    1991-01-01

    The TOPEX/POSEIDON mission will determine global changes of sea level with unprecedented accuracy. Our main objective is the use TOPEX/POSEIDON data, concurrent in situ ocean measurements, and other satellite observations to document and diagnose physical processes by which heat is exchanged with the atmosphere, stored in the ocean, or transported by ocean circulation. During the prelaunch period, our objectives are to advise the project on an improved method of retrieving sea level data and prepare for the application of TOPEX/POSEIDON data by developing a diagnostic model using in situ measurements and altimeter observations from Geosat and the European Remote Sensing satellite.

  15. Barium stable isotopes in the global ocean: Tracer of Ba inputs and utilization

    NASA Astrophysics Data System (ADS)

    Hsieh, Yu-Te; Henderson, Gideon M.

    2017-09-01

    Barium has been used as a biogeochemical tracer for alkalinity, productivity, and riverine inputs in the ocean, but its oceanic cycle remains poorly constrained. Barium stable isotope measurements may improve the use of Ba as a tracer and better constrain the cycling of Ba, but data are only available in limited regions of the oceans. In this study, we present dissolved seawater Ba isotopic compositions in a sample collection spanning the North Atlantic, South Atlantic, North Pacific and Southern Oceans. Compiled global upper-ocean [Ba] data show a relatively constant [Ba] (35-45 nM) in the near-surface waters throughout the global ocean, with the exception of areas near river inputs or strong upwelling. The relatively uniform distribution of [Ba] in the upper ocean seawater indicates that Ba removal is slow relative to supply and mixing, and implies that near-surface Ba isotope values are controlled by basin-scale balances rather than by regional or short-term processes. Seawater Ba isotopic compositions show a large variation of δ 138 / 134 Ba values ranging from 0.24 to 0.65‰, and a tight relationship with [Ba]. This global relationship can be simply modelled assuming a primary deep Southern Ocean source for Ba to yield a maximum isotope fractionation of α = 1.00058 ± 0.00010 (α =seawater 138/134Ba/particle 138/134Ba). This suggested isotope fractionation during Ba removal from seawater is larger than implied by laboratory measurement during barite formation, suggesting additional fractionating phases or a two-stage fractionation process. Riverine input from the Rio de la Plata to the South Atlantic has a signature of δ 138 / 134 Ba = - 0.06- 0.11 ‰, which is too light to explain the heavy values (>0.58‰) observed in the surface open ocean. Globally, the Ba isotope composition of the upper ocean waters is correlated with the fraction of Ba utilization at the basin scale (which varies from <15 to 70% at sites studied here). In the deep Atlantic Ocean

  16. U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model

    DTIC Science & Technology

    2006-09-30

    the mean currents/SSH fronts more sharply than is presently possible from an observation-based mean, even the state-of-the- art mean of Maximenko and... MODAS ). J. Atmos. Oceanic Tech., 19, 240-252. Gibson, J.K., P. Kallberg, S. Uppala, A. Hernandez, A. Nomura and E. Serrano, 1997. ECMWF Re- Analysis

  17. An Analysis of an Eddy-Resolving Global Ocean Model in the Tropical Indian Ocean

    DTIC Science & Technology

    1990-09-01

    Ocean circulation. The seasonally-reversing Somali Current is simulated by the model, and includes seasonai undercurrents and a tvo-gyre system during...undercurrents and a two-gyre system during the southwest monson. Westward-flow occ,, rs beneath the Southwest Monsoon Current during June and July. The...25 F. THE SOMALI CURRENT SYSTEM ....................................... 28 G. THROUGHFLOW IN THE

  18. Insights into global diatom distribution and diversity in the world’s ocean

    PubMed Central

    Malviya, Shruti; Scalco, Eleonora; Audic, Stéphane; Vincent, Flora; Veluchamy, Alaguraj; Poulain, Julie; Wincker, Patrick; Iudicone, Daniele; de Vargas, Colomban; Bittner, Lucie; Zingone, Adriana; Bowler, Chris

    2016-01-01

    Diatoms (Bacillariophyta) constitute one of the most diverse and ecologically important groups of phytoplankton. They are considered to be particularly important in nutrient-rich coastal ecosystems and at high latitudes, but considerably less so in the oligotrophic open ocean. The Tara Oceans circumnavigation collected samples from a wide range of oceanic regions using a standardized sampling procedure. Here, a total of ∼12 million diatom V9-18S ribosomal DNA (rDNA) ribotypes, derived from 293 size-fractionated plankton communities collected at 46 sampling sites across the global ocean euphotic zone, have been analyzed to explore diatom global diversity and community composition. We provide a new estimate of diversity of marine planktonic diatoms at 4,748 operational taxonomic units (OTUs). Based on the total assigned ribotypes, Chaetoceros was the most abundant and diverse genus, followed by Fragilariopsis, Thalassiosira, and Corethron. We found only a few cosmopolitan ribotypes displaying an even distribution across stations and high abundance, many of which could not be assigned with confidence to any known genus. Three distinct communities from South Pacific, Mediterranean, and Southern Ocean waters were identified that share a substantial percentage of ribotypes within them. Sudden drops in diversity were observed at Cape Agulhas, which separates the Indian and Atlantic Oceans, and across the Drake Passage between the Atlantic and Southern Oceans, indicating the importance of these ocean circulation choke points in constraining diatom distribution and diversity. We also observed high diatom diversity in the open ocean, suggesting that diatoms may be more relevant in these oceanic systems than generally considered. PMID:26929361

  19. Insights into global diatom distribution and diversity in the world's ocean.

    PubMed

    Malviya, Shruti; Scalco, Eleonora; Audic, Stéphane; Vincent, Flora; Veluchamy, Alaguraj; Poulain, Julie; Wincker, Patrick; Iudicone, Daniele; de Vargas, Colomban; Bittner, Lucie; Zingone, Adriana; Bowler, Chris

    2016-03-15

    Diatoms (Bacillariophyta) constitute one of the most diverse and ecologically important groups of phytoplankton. They are considered to be particularly important in nutrient-rich coastal ecosystems and at high latitudes, but considerably less so in the oligotrophic open ocean. The Tara Oceans circumnavigation collected samples from a wide range of oceanic regions using a standardized sampling procedure. Here, a total of ∼12 million diatom V9-18S ribosomal DNA (rDNA) ribotypes, derived from 293 size-fractionated plankton communities collected at 46 sampling sites across the global ocean euphotic zone, have been analyzed to explore diatom global diversity and community composition. We provide a new estimate of diversity of marine planktonic diatoms at 4,748 operational taxonomic units (OTUs). Based on the total assigned ribotypes, Chaetoceros was the most abundant and diverse genus, followed by Fragilariopsis, Thalassiosira, and Corethron We found only a few cosmopolitan ribotypes displaying an even distribution across stations and high abundance, many of which could not be assigned with confidence to any known genus. Three distinct communities from South Pacific, Mediterranean, and Southern Ocean waters were identified that share a substantial percentage of ribotypes within them. Sudden drops in diversity were observed at Cape Agulhas, which separates the Indian and Atlantic Oceans, and across the Drake Passage between the Atlantic and Southern Oceans, indicating the importance of these ocean circulation choke points in constraining diatom distribution and diversity. We also observed high diatom diversity in the open ocean, suggesting that diatoms may be more relevant in these oceanic systems than generally considered.

  20. Spiraling pathways of global deep waters to the surface of the Southern Ocean.

    PubMed

    Tamsitt, Veronica; Drake, Henri F; Morrison, Adele K; Talley, Lynne D; Dufour, Carolina O; Gray, Alison R; Griffies, Stephen M; Mazloff, Matthew R; Sarmiento, Jorge L; Wang, Jinbo; Weijer, Wilbert

    2017-08-02

    Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60-90 years.Deep waters of the Atlantic, Pacific and Indian Oceans upwell in the Southern Oceanbut the exact pathways are not fully characterized. Here the authors present a three dimensional view showing a spiralling southward path, with enhanced upwelling by eddy-transport at topographic hotspots.

  1. The complementary role of SMOS sea surface salinity observations for estimating global ocean salinity state

    NASA Astrophysics Data System (ADS)

    Lu, Zeting; Cheng, Lijing; Zhu, Jiang; Lin, Renping

    2016-06-01

    Salinity is a key ocean state property, changes in which reveal the variation of the water cycle and the ocean thermohaline circulation. However, prior to this century, in situ salinity observations were extremely sparse, which decreased the reliability of simulations of ocean general circulation by ocean and climate models. In 2009, sea surface salinity (SSS) observations covered the global ocean via the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission, and several versions of global SSS products were subsequently released. How can these data benefit model performance? Previous studies found contradictory results. In this work, we assimilated SMOS-SSS data into the LASG/IAP Climate system Ocean Model (LICOM) using the Ensemble Optimum Interpolation (EnOI) assimilation scheme. To assess and quantify the contribution of SMOS-SSS data to model performance, several tests were conducted. The results indicate that the CECOS/CATDS 2010.V02 SMOS-SSS product can significantly improve model simulations of sea surface/subsurface salinity fields. This study provides the basis for the future assimilation of SMOS-SSS data for short-range climate forecasting.

  2. A Southern Ocean variability study using the Argo-based Model for Investigation of the Global Ocean (AMIGO)

    NASA Astrophysics Data System (ADS)

    Lebedev, Konstantin

    2017-04-01

    The era of satellite observations of the ocean surface that started at the end of the 20th century and the development of the Argo project in the first years of the 21st century, designed to collect information of the upper 2000 m of the ocean using satellites, provides unique opportunities for continuous monitoring of the Global Ocean state. Starting from 2005, measurements with the Argo floats have been performed over the majority of the World Ocean. In November 2007, the Argo program reached coverage of 3000 simultaneously operating floats (one float in a three-degree square) planned during the development of the program. Currently, 4000 Argo floats autonomously profile the upper 2000-m water column of the ocean from Antarctica to Spitsbergen increasing World Ocean temperature and salinity databases by 12000 profiles per month. This makes it possible to solve problems on reconstructing and monitoring the ocean state on an almost real-time basis, study the ocean dynamics, obtain reasonable estimates of the climatic state of the ocean in the last decade and estimate existing intraclimatic trends. We present the newly developed Argo-Based Model for Investigation of the Global Ocean (AMIGO), which consists of a block for variational interpolation of the profiles of drifting Argo floats to a regular grid and a block for model hydrodynamic adjustment of variationally interpolated fields. Such a method makes it possible to obtain a full set of oceanographic characteristics - temperature, salinity, density, and current velocity - using irregularly located Argo measurements (the principle of the variational interpolation technique entails minimization of the misfit between the interpolated fields defined on the regular grid and irregularly distributed data; hence the optimal solution passes as close to the data as possible). The simulations were performed for the entire globe limited in the north by 85.5° N using 1° grid spacing in both longitude and latitude. At the

  3. Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese

    NASA Astrophysics Data System (ADS)

    van Hulten, Marco; Middag, Rob; Dutay, Jean-Claude; de Baar, Hein; Roy-Barman, Matthieu; Gehlen, Marion; Tagliabue, Alessandro; Sterl, Andreas

    2017-03-01

    Dissolved manganese (Mn) is a biologically essential element. Moreover, its oxidised form is involved in removing itself and several other trace elements from ocean waters. Here we report the longest thus far (17 500 km length) full-depth ocean section of dissolved Mn in the west Atlantic Ocean, comprising 1320 data values of high accuracy. This is the GA02 transect that is part of the GEOTRACES programme, which aims to understand trace element distributions. The goal of this study is to combine these new observations with new, state-of-the-art, modelling to give a first assessment of the main sources and redistribution of Mn throughout the ocean. To this end, we simulate the distribution of dissolved Mn using a global-scale circulation model. This first model includes simple parameterisations to account for the sources, processes and sinks of Mn in the ocean. Oxidation and (photo)reduction, aggregation and settling, as well as biological uptake and remineralisation by plankton are included in the model. Our model provides, together with the observations, the following insights: - The high surface concentrations of manganese are caused by the combination of photoreduction and sources contributing to the upper ocean. The most important sources are sediments, dust, and, more locally, rivers. - Observations and model simulations suggest that surface Mn in the Atlantic Ocean moves downwards into the southward-flowing North Atlantic Deep Water (NADW), but because of strong removal rates there is no elevated concentration of Mn visible any more in the NADW south of 40° N. - The model predicts lower dissolved Mn in surface waters of the Pacific Ocean than the observed concentrations. The intense oxygen minimum zone (OMZ) in subsurface waters is deemed to be a major source of dissolved Mn also mixing upwards into surface waters, but the OMZ is not well represented by the model. Improved high-resolution simulation of the OMZ may solve this problem. - There is a mainly

  4. Long-term changes in dissolved oxygen concentrations in the ocean caused by protracted global warming

    NASA Astrophysics Data System (ADS)

    Matear, R. J.; Hirst, A. C.

    2003-12-01

    In the Earth's geological record massive marine ecological change has been attributed to the occurrence of widespread anoxia in the ocean [, 2002; , 2002; , 1996]. Climate change projection till the end of this century predict a 4 to 7% decline in the dissolve oxygen in the ocean [, 2002; , 2000; , 2001; , 1998] suggesting the potential for global warming to eventually drive the deep ocean anoxic. To examine the multicentury impact of protracted global warming on oceanic concentrations of dissolved oxygen, we use a climate system model and a low-order oceanic biogeochemical model. The models are integrated for an atmospheric equivalent CO2 concentration, which is specified to triple according to a standard scenario from the late nineteenth to the late twenty-first century, and then is subsequently held constant at that elevated level for an additional 6 centuries. For the present day, the model successfully reproduced the large-scale features of the dissolved oxygen field in the ocean. In the global warming simulation, the physical model displays marked changes in high-latitude oceanic stratification and overturning, including near-cessation of deep water renewal for depths greater than about 1.5 km during the period of elevated stable CO2 concentration. Our model predicts a decline in oxygen concentration through most of the subsurface ocean. Concentration changes in the thermocline waters result mainly from solubility changes in the upstream source waters, while changes in the deep waters result mainly from lack of ventilation and ongoing consumption of oxygen by remineralization of sinking particulate organic matter. Changes in the upper 2 km of the ocean generally show signs of equilibration by the end of the integration, but at greater depths, there occurs a slow but steady decline through to the end of the integration. By the end of the integration, we simulate a doubling of the volume of hypoxic water (less than 10 μmol/kg) in the thermocline of the eastern

  5. A global seasonal surface ocean climatology of phytoplankton types based on CHEMTAX analysis of HPLC pigments

    NASA Astrophysics Data System (ADS)

    Swan, Chantal M.; Vogt, Meike; Gruber, Nicolas; Laufkoetter, Charlotte

    2016-03-01

    Much advancement has been made in recent years in field data assimilation, remote sensing and ecosystem modeling, yet our global view of phytoplankton biogeography beyond chlorophyll biomass is still a cursory taxonomic picture with vast areas of the open ocean requiring field validations. High performance liquid chromatography (HPLC) pigment data combined with inverse methods offer an advantage over many other phytoplankton quantification measures by way of providing an immediate perspective of the whole phytoplankton community in a sample as a function of chlorophyll biomass. Historically, such chemotaxonomic analysis has been conducted mainly at local spatial and temporal scales in the ocean. Here, we apply a widely tested inverse approach, CHEMTAX, to a global climatology of pigment observations from HPLC. This study marks the first systematic and objective global application of CHEMTAX, yielding a seasonal climatology comprised of ~1500 1°×1° global grid points of the major phytoplankton pigment types in the ocean characterizing cyanobacteria, haptophytes, chlorophytes, cryptophytes, dinoflagellates, and diatoms, with results validated against prior regional studies where possible. Key findings from this new global view of specific phytoplankton abundances from pigments are a) the large global proportion of marine haptophytes (comprising 32±5% of total chlorophyll), whose biogeochemical functional roles are relatively unknown, and b) the contrasting spatial scales of complexity in global community structure that can be explained in part by regional oceanographic conditions. The results are publically accessible via

  6. Weak response of oceanic dimethylsulfide to upper mixing shoaling induced by global warming.

    PubMed

    Vallina, S M; Simó, R; Manizza, M

    2007-10-09

    The solar radiation dose in the oceanic upper mixed layer (SRD) has recently been identified as the main climatic force driving global dimethylsulfide (DMS) dynamics and seasonality. Because DMS is suggested to exert a cooling effect on the earth radiative budget through its involvement in the formation and optical properties of tropospheric clouds over the ocean, a positive relationship between DMS and the SRD supports the occurrence of a negative feedback between the oceanic biosphere and climate, as postulated 20 years ago. Such a natural feedback might partly counteract anthropogenic global warming through a shoaling of the mixed layer depth (MLD) and a consequent increase of the SRD and DMS concentrations and emission. By applying two globally derived DMS diagnostic models to global fields of MLD and chlorophyll simulated with an Ocean General Circulation Model coupled to a biogeochemistry model for a 50% increase of atmospheric CO(2) and an unperturbed control run, we have estimated the response of the DMS-producing pelagic ocean to global warming. Our results show a net global increase in surface DMS concentrations, especially in summer. This increase, however, is so weak (globally 1.2%) that it can hardly be relevant as compared with the radiative forcing of the increase of greenhouse gases. This contrasts with the seasonal variability of DMS (1000-2000% summer-to-winter ratio). We suggest that the "plankton-DMS-clouds-earth albedo feedback" hypothesis is less strong a long-term thermostatic system than a seasonal mechanism that contributes to regulate the solar radiation doses reaching the earth's biosphere.

  7. 135 years of global ocean warming between the Challenger expedition and the Argo Programme

    NASA Astrophysics Data System (ADS)

    Roemmich, Dean; John Gould, W.; Gilson, John

    2012-06-01

    Changing temperature throughout the oceans is a key indicator of climate change. Since the 1960s about 90% of the excess heat added to the Earth's climate system has been stored in the oceans. The ocean's dominant role over the atmosphere, land, or cryosphere comes from its high heat capacity and ability to remove heat from the sea surface by currents and mixing. The longest interval over which instrumental records of subsurface global-scale temperature can be compared is the 135 years between the voyage of HMS Challenger (1872-1876) and the modern data set of the Argo Programme (2004-2010). Argo's unprecedented global coverage permits its comparison with any earlier measurements. This, the first global-scale comparison of Challenger and modern data, shows spatial mean warming at the surface of 0.59°C+/-0.12, consistent with previous estimates of globally averaged sea surface temperature increase. Below the surface the mean warming decreases to 0.39°C+/-0.18 at 366m (200fathoms) and 0.12°C+/-0.07 at 914m (500fathoms). The 0.33°C+/-0.14 average temperature difference from 0 to 700m is twice the value observed globally in that depth range over the past 50 years, implying a centennial timescale for the present rate of global warming. Warming in the Atlantic Ocean is stronger than in the Pacific. Systematic errors in the Challenger data mean that these temperature changes are a lower bound on the actual values. This study underlines the scientific significance of the Challenger expedition and the modern Argo Programme and indicates that globally the oceans have been warming at least since the late-nineteenth or early-twentieth century.

  8. Sensitivity of a global coupled ocean-sea ice model to the parameterization of vertical mixing

    NASA Astrophysics Data System (ADS)

    Goosse, H.; Deleersnijder, E.; Fichefet, T.; England, M. H.

    1999-06-01

    Three numerical experiments have been carried out with a global coupled ice-ocean model to investigate its sensitivity to the treatment of vertical mixing in the upper ocean. In the first experiment, a widely used fixed profile of vertical diffusivity and viscosity is imposed, with large values in the upper 50 m to crudely represent wind-driven mixing. In the second experiment, the eddy coefficients are functions of the Richardson number, and, in the third case, a relatively sophisticated parameterization, based on the turbulence closure scheme of Mellor and Yamada version 2.5, is introduced. We monitor the way the different mixing schemes affect the simulated ocean ventilation, water mass properties, and sea ice distributions. CFC uptake is also diagnosed in the model experiments. The simulation of the mixed layer depth is improved in the experiment which includes the sophisticated turbulence closure scheme. This results in a good representation of the upper ocean thermohaline structure and in heat exchange with the atmosphere within the range of current estimates. However, the error in heat flux in the experiment with simple fixed vertical mixing coefficients can be as high as 50 W m-2 in zonal mean during summer. Using CFC tracers allows us to demonstrate that the ventilation of the deep ocean is not significantly influenced by the parameterization of vertical mixing in the upper ocean. The only exception is the Southern Ocean. There, the ventilation is too strong in all three experiments. However, modifications of the vertical diffusivity and, surprisingly, the vertical viscosity significantly affect the stability of the water column in this region through their influence on upper ocean salinity, resulting in a more realistic Southern Ocean circulation. The turbulence scheme also results in an improved simulation of Antarctic sea ice coverage. This is due to to a better simulation of the mixed layer depth and thus of heat exchanges between ice and ocean. The

  9. Internally Consistent MODIS Estimate of Aerosol Clear-Sky Radiative Effect Over the Global Oceans

    NASA Technical Reports Server (NTRS)

    Remer, Lorraine A.; Kaufman, Yoram J.

    2004-01-01

    Modern satellite remote sensing, and in particular the MODerate resolution Imaging Spectroradiometer (MODIS), offers a measurement-based pathway to estimate global aerosol radiative effects and aerosol radiative forcing. Over the Oceans, MODIS retrieves the total aerosol optical thickness, but also reports which combination of the 9 different aerosol models was used to obtain the retrieval. Each of the 9 models is characterized by a size distribution and complex refractive index, which through Mie calculations correspond to a unique set of single scattering albedo, assymetry parameter and spectral extinction for each model. The combination of these sets of optical parameters weighted by the optical thickness attributed to each model in the retrieval produces the best fit to the observed radiances at the top of the atmosphere. Thus the MODIS Ocean aerosol retrieval provides us with (1) An observed distribution of global aerosol loading, and (2) An internally-consistent, observed, distribution of aerosol optical models that when used in combination will best represent the radiances at the top of the atmosphere. We use these two observed global distributions to initialize the column climate model by Chou and Suarez to calculate the aerosol radiative effect at top of the atmosphere and the radiative efficiency of the aerosols over the global oceans. We apply the analysis to 3 years of MODIS retrievals from the Terra satellite and produce global and regional, seasonally varying, estimates of aerosol radiative effect over the clear-sky oceans.

  10. The effect of atmospheric nitrogen deposition on marine nitrogen cycling throughout the global ocean

    NASA Astrophysics Data System (ADS)

    Somes, Christopher; Oschlies, Andreas

    2014-05-01

    The rapidly increasing rate of anthropogenic nitrogen deposition has the potential to perturb marine ecosystems and biogeochemical cycles because nitrogen is one of the major limiting nutrients in the ocean. We use an Earth System Climate Model that includes ocean biogeochemistry to assess the impact of atmospheric nitrogen deposition. Experiments are conducted where we artificially add nitrogen to nearly all locations individually throughout the global surface ocean using a nitrogen deposition rate of 700 mg N m-2 yr-1, which is consistent with modern estimates near industrial areas. We identify oceanic "biomes" that respond differently to atmospheric nitrogen deposition. (1) When nitrogen is deposited near oxygen minimum zones where water column denitrification occurs, locally increased primary production stimulates additional denitrification. Since water column denitrification removes 7 mol N for every mol N of newly formed organic matter respired, the global oceanic nitrogen inventory declines in response to nitrogen deposition in these areas. This slow, but steady decline persists for at least 1,000 years. (2) When nitrogen is deposited above shallow continental shelves where benthic denitrification occurs, our benthic denitrification model predicts an increase that is nearly equal to the nitrogen deposited and thus no net change in the global nitrogen inventory. (3) When nitrogen is deposited into the high latitude open ocean far removed from nitrogen fixation and denitrification, all of this deposited nitrogen initially accumulates in the ocean. This nitrogen eventually circulates into the tropical oxygen minimum zones where it fuels additional primary production and denitrification, which removes nitrogen at a rate equal to the deposition after 1,000 years and leads to a stable, but increased nitrogen inventory in our model. (4) When nitrogen is deposited into the open ocean where nitrogen fixation occurs, nitrogen fixation decreases due to less nitrogen

  11. GLOBEC (Global Ocean Ecosystems Dynamics: Northwest Atlantic program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The specific objective of the meeting was to plan an experiment in the Northwestern Atlantic to study the marine ecosystem and its role, together with that of climate and physical dynamics, in determining fisheries recruitment. The underlying focus of the GLOBEC initiative is to understand the marine ecosystem as it related to marine living resources and to understand how fluctuation in these resources are driven by climate change and exploitation. In this sense the goal is a solid scientific program to provide basic information concerning major fisheries stocks and the environment that sustains them. The plan is to attempt to reach this understanding through a multidisciplinary program that brings to bear new techniques as disparate as numerical fluid dynamic models of ocean circulation, molecular biology and modern acoustic imaging. The effort will also make use of the massive historical data sets on fisheries and the state of the climate in a coordinated manner.

  12. Ocean surface currents reconstruction at a global scale from SST microwave measurements

    NASA Astrophysics Data System (ADS)

    González-Haro, Cristina; Isern-Fontanet, Jordi

    2013-04-01

    Accurately identifying ocean circulation is crucial to our understanding of climate and ocean processes and building as reliable as possible ocean current datasets is important for operational tasks and navigation. This requires acquiring synoptic measurements of the ocean velocity field. Although velocity fields derived from altimetric measurements are extensively used, distances between tracks are generally large, and that restricts the scales of the obtained velocity field below 100-150 Km. In addition, the limited number of available altimeters leads to errors in the accurate location of oceanic currents, which limits the quantitative reconstruction of the velocity field using exclusively altimeters. To circumvent such a limitation, other sources of satellite data, such as sea surface temperature (SST), can be considered. New methodologies based on Surface Quasi-Geostrophic (SQG) theory allow to reconstruct ocean velocity fields from only a snapshot of SST. The good results obtained after applying this methodology to infrared SST images in the Mediterranean led us to validate this approach at a global scale. However, applying this methodology at a planetary-scale is not straightforward. First, the cloud cover at a global scale is too large to reconstruct the velocity field in a routine way. This problem can be solved if global SST images observed with microwave radiometers are used. In this presentation, we evaluate surface ocean current reconstruction at a global scale from microwave SST measurements, based on the Surface Quasi-Geostrophic (SQG) theory. A new heuristic method that combines the benefits of microwave and altimetry measurements is also presented and evaluated. Results showed that the reconstruction of surface currents based on SQG theory can be improved if the information about the energy spectrum provided by altimeters is used.

  13. Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Le Quéré, Corinne; Buitenhuis, Erik T.; Moriarty, Róisín; Alvain, Séverine; Aumont, Olivier; Bopp, Laurent; Chollet, Sophie; Enright, Clare; Franklin, Daniel J.; Geider, Richard J.; Harrison, Sandy P.; Hirst, Andrew G.; Larsen, Stuart; Legendre, Louis; Platt, Trevor; Prentice, I. Colin; Rivkin, Richard B.; Sailley, Sévrine; Sathyendranath, Shubha; Stephens, Nick; Vogt, Meike; Vallina, Sergio M.

    2016-07-01

    Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs): six types of phytoplankton, three types of zooplankton, and heterotrophic procaryotes. We improved the representation of zooplankton dynamics in our model through (a) the explicit inclusion of large, slow-growing macrozooplankton (e.g. krill), and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean high-nutrient low-chlorophyll (HNLC) region during summer. When model simulations do not include macrozooplankton grazing explicitly, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when there is no iron deposition from dust. When model simulations include a slow-growing macrozooplankton and trophic cascades among three zooplankton types, the high-chlorophyll summer bias in the Southern Ocean HNLC region largely disappears. Our model results suggest that the observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community, despite iron limitation of phytoplankton community growth rates. This result has implications for the representation of global biogeochemical cycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean.

  14. Tracing dust input to the global ocean using thorium isotopes in marine sediments: ThoroMap

    NASA Astrophysics Data System (ADS)

    Kienast, S. S.; Winckler, G.; Lippold, J.; Albani, S.; Mahowald, N. M.

    2016-10-01

    Continental dust input into the ocean-atmosphere system has significant ramifications for biogeochemical cycles and global climate, yet direct observations of dust deposition in the ocean remain scarce. The long-lived isotope thorium-232 (232Th) is greatly enriched in upper continental crust compared to oceanic crust and mid-ocean ridge basalt-like volcanogenic material. In open ocean sediments, away from fluvial and ice-rafted sources of continental material, 232Th is often assumed to be of predominantly eolian origin. In conjunction with flux normalization based on the particle reactive radioisotope thorium-230 (230Th), 232Th measurements in marine sediments are a promising proxy for dust accumulation in the modern and past ocean. Here we present ThoroMap, a new global data compilation of 230Th-normalized fluxes of 232Th. After careful screening, we derive dust deposition estimates in the global ocean averaged for the late Holocene (0-4 ka) and the Last Glacial Maximum (LGM, 19-23 ka). ThoroMap is compared with dust deposition estimates derived from the Community Climate System Model (CCSM3) and CCSM4, two coupled atmosphere, land, ocean, and sea ice models. Model-data correlation factors are 0.63 (CCSM3) and 0.59 (CCSM4) in the late Holocene and 0.82 (CCSM3) and 0.83 (CCSM4) in the LGM. ThoroMap is the first compilation that is built on a single, specific proxy for dust and that exclusively uses flux-normalization to derive dust deposition rates.

  15. Upper ocean ecosystem dynamics and iron cycling in a global three-dimensional model

    NASA Astrophysics Data System (ADS)

    Moore, J. Keith; Doney, Scott C.; Lindsay, Keith

    2004-12-01

    A global three-dimensional marine ecosystem model with several key phytoplankton functional groups, multiple limiting nutrients, explicit iron cycling, and a mineral ballast/organic matter parameterization is run within a global ocean circulation model. The coupled biogeochemistry/ecosystem/circulation (BEC) model reproduces known basin-scale patterns of primary and export production, biogenic silica production, calcification, chlorophyll, macronutrient and dissolved iron concentrations. The model captures observed high nitrate, low chlorophyll (HNLC) conditions in the Southern Ocean, subarctic and equatorial Pacific. Spatial distributions of nitrogen fixation are in general agreement with field data, with total N-fixation of 55 Tg N. Diazotrophs directly account for a small fraction of primary production (0.5%) but indirectly support 10% of primary production and 8% of sinking particulate organic carbon (POC) export. Diatoms disproportionately contribute to export of POC out of surface waters, but CaCO3 from the coccolithophores is the key driver of POC flux to the deep ocean in the model. An iron source from shallow ocean sediments is found critical in preventing iron limitation in shelf regions, most notably in the Arctic Ocean, but has a relatively localized impact. In contrast, global-scale primary production, export production, and nitrogen fixation are all sensitive to variations in atmospheric mineral dust inputs. The residence time for dissolved iron in the upper ocean is estimated to be a few years to a decade. Most of the iron utilized by phytoplankton is from subsurface sources supplied by mixing, entrainment, and ocean circulation. However, owing to the short residence time of iron in the upper ocean, this subsurface iron pool is critically dependent on continual replenishment from atmospheric dust deposition and, to a lesser extent, lateral transport from shelf regions.

  16. Biogeochemical drivers of the fate of riverine mercury discharged to the global and Arctic oceans

    NASA Astrophysics Data System (ADS)

    Zhang, Yanxu; Jacob, Daniel J.; Dutkiewicz, Stephanie; Amos, Helen M.; Long, Michael S.; Sunderland, Elsie M.

    2015-06-01

    Rivers discharge 28 ± 13 Mmol yr-1 of mercury (Hg) to ocean margins, an amount comparable to atmospheric deposition to the global oceans. Most of the Hg discharged by rivers is sequestered by burial of benthic sediment in estuaries or the coastal zone, but some is evaded to the atmosphere and some is exported to the open ocean. We investigate the fate of riverine Hg by developing a new global 3-D simulation for Hg in the Massachusetts Institute of Technology ocean general circulation model. The model includes plankton dynamics and carbon respiration (DARWIN project model) coupled to inorganic Hg chemistry. Results are consistent with observed spatial patterns and magnitudes of surface ocean Hg concentrations. We use observational constraints on seawater Hg concentrations and evasion to infer that most Hg from rivers is sorbed to refractory organic carbon and preferentially buried. Only 6% of Hg discharged by rivers (1.8 Mmol yr-1) is transported to the open ocean on a global basis. This fraction varies from a low of 2.6% in East Asia due to the barrier imposed by the Korean Peninsula and Japanese archipelago, up to 25% in eastern North America facilitated by the Gulf Stream. In the Arctic Ocean, low tributary particle loads and efficient degradation of particulate organic carbon by deltaic microbial communities favor a more labile riverine Hg pool. Evasion of Hg to the Arctic atmosphere is indirectly enhanced by heat transport during spring freshet that accelerates sea ice melt and ice rafting. Discharges of 0.23 Mmol Hg yr-1 from Arctic rivers can explain the observed summer maximum in the Arctic atmosphere, and this magnitude of releases is consistent with recent observations. Our work indicates that rivers are major contributors to Hg loads in the Arctic Ocean.

  17. C-GLORSv5: an improved multipurpose global ocean eddy-permitting physical reanalysis

    NASA Astrophysics Data System (ADS)

    Storto, Andrea; Masina, Simona

    2016-11-01

    Global ocean reanalyses combine in situ and satellite ocean observations with a general circulation ocean model to estimate the time-evolving state of the ocean, and they represent a valuable tool for a variety of applications, ranging from climate monitoring and process studies to downstream applications, initialization of long-range forecasts and regional studies. The purpose of this paper is to document the recent upgrade of C-GLORS (version 5), the latest ocean reanalysis produced at the Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC) that covers the meteorological satellite era (1980-present) and it is being updated in delayed time mode. The reanalysis is run at eddy-permitting resolution (1/4° horizontal resolution and 50 vertical levels) and consists of a three-dimensional variational data assimilation system, a surface nudging and a bias correction scheme. With respect to the previous version (v4), C-GLORSv5 contains a number of improvements. In particular, background- and observation-error covariances have been retuned, allowing a flow-dependent inflation in the globally averaged background-error variance. An additional constraint on the Arctic sea-ice thickness was introduced, leading to a realistic ice volume evolution. Finally, the bias correction scheme and the initialization strategy were retuned. Results document that the new reanalysis outperforms the previous version in many aspects, especially in representing the variability of global heat content and associated steric sea level in the last decade, the top 80 m ocean temperature biases and root mean square errors, and the Atlantic Ocean meridional overturning circulation; slight worsening in the high-latitude salinity and deep ocean temperature emerge though, providing the motivation for further tuning of the reanalysis system. The dataset is available in NetCDF format at doi:10.1594/PANGAEA.857995.

  18. Atmosphere-ocean ozone exchange: A global modeling study of biogeochemical, atmospheric, and waterside turbulence dependencies

    NASA Astrophysics Data System (ADS)

    Ganzeveld, L.; Helmig, D.; Fairall, C. W.; Hare, J.; Pozzer, A.

    2009-12-01

    The significance of the removal of tropospheric ozone by the oceans, covering ˜2/3 of the Earth's surface, has only been addressed in a few studies involving water tank, aircraft, and tower flux measurements. On the basis of results from these few observations of the ozone dry deposition velocity (VdO3), atmospheric chemistry models generally apply an empirical, constant ocean uptake rate of 0.05 cm s-1. This value is substantially smaller than the atmospheric turbulent transport velocity for ozone. On the other hand, the uptake is higher than expected from the solubility of ozone in clean water alone, suggesting that there is an enhancement in oceanic ozone uptake, e.g., through a chemical destruction mechanism. We present an evaluation of a global-scale analysis with a new mechanistic representation of atmosphere-ocean ozone exchange. The applied atmosphere chemistry-climate model includes not only atmospheric but also waterside turbulence and the role of waterside chemical loss processes as a function of oceanic biogeochemistry. The simulations suggest a larger role of biogeochemistry in tropical and subtropical ozone oceanic uptake with a relative small temporal variability, whereas in midlatitude and high-latitude regions, highly variable ozone uptake rates are expected because of the stronger influence of waterside turbulence. Despite a relatively large range in the explicitly calculated ocean uptake rate, there is a surprisingly small sensitivity of simulated Marine Boundary Layer ozone concentrations compared to the sensitivity for the commonly applied constant ocean uptake approach. This small sensitivity points at compensating effects through inclusion of the process-based ocean uptake mechanisms to consider variability in oceanic O3 deposition consistent with that in atmospheric and oceanic physical, chemical, and biological processes.

  19. Sensitivity of simulated global-scale freshwater fluxes and storages to input data, hydrological model structure, human water use and calibration

    NASA Astrophysics Data System (ADS)

    Müller Schmied, H.; Eisner, S.; Franz, D.; Wattenbach, M.; Portmann, F. T.; Flörke, M.; Döll, P.

    2014-09-01

    Global-scale assessments of freshwater fluxes and storages by hydrological models under historic climate conditions are subject to a variety of uncertainties. Using the global hydrological model WaterGAP (Water - Global Assessment and Prognosis) 2.2, we investigated the sensitivity of simulated freshwater fluxes and water storage variations to five major sources of uncertainty: climate forcing, land cover input, model structure/refinements, consideration of human water use and calibration (or no calibration) against observed mean river discharge. In a modeling experiment, five variants of the standard version of WaterGAP 2.2 were generated that differed from the standard version only regarding the investigated source of uncertainty. The basin-specific calibration approach for WaterGAP was found to have the largest effect on grid cell fluxes as well as on global AET (actual evapotranspiration) and discharge into oceans for the period 1971-2000. Regarding grid cell fluxes, climate forcing ranks second before land cover input. Global water storage trends are most sensitive to model refinements (mainly modeling of groundwater depletion) and consideration of human water use. The best fit to observed time series of monthly river discharge or discharge seasonality is obtained with the standard WaterGAP 2.2 model version which is calibrated and driven by daily reanalysis-based WFD/WFDEI (combination of Watch Forcing Data based on ERA40 and Watch Forcing Data based on ERA-Interim) climate data. Discharge computed by a calibrated model version using monthly CRU TS (Climate Research Unit time-series) 3.2 and GPCC (Global Precipitation Climatology Center) v6 climate input reduced the fit to observed discharge for most stations. Taking into account uncertainties of climate and land cover data, global 1971-2000 discharge into oceans and inland sinks ranges between 40 000 and 42 000 km3 yr-1. Global actual evapotranspiration, with 70 000 km3 yr-1, is rather unaffected by climate

  20. U. S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model

    DTIC Science & Technology

    2009-01-01

    This is a very good comparison in relation to the present state of the art (Bryan et al., 2007; Chassignet and Marshall, 2008), with the model...profiles computed from the Modular Ocean Data Assimilation System ( MODAS ). These profiles are only created where the satellite based SSH anomalies with... MODAS approach yielded much smaller bias and RMSE than the CH approach (Fig. 4). Thus MODAS synthetics were chosen for the downward projection

  1. U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model

    DTIC Science & Technology

    2007-09-30

    models with fixed depth z-level coordinates, terrain following coordinates, generalized coordinates (HYCOM), and unstructured grids. (5) To facilitate...days of atmospheric forecast forcing. A total of 8007 temperature profiles from fixed buoys and ARGO floats (fairly evenly distributed between 65°S...E.P. Chassignet and G. Halliwell, 2006: Value of bulk heat flux parameterizations for ocean SST prediction. J. Mar. Sys. (submitted) Zamudio , L

  2. Global Ocean Forecast System 3.1 Validation Test

    DTIC Science & Technology

    2017-05-04

    Naval Research Laboratory Stennis Space Center, MS 39529-5004 NRL/MR/7320--17-9722 Approved for public release; distribution is unlimited. Global...Solutions, Inc. Stennis Space Center, Mississippi luis zaMudio-lopEz Florida State University Tallahassee, Florida MichaEl W. phElps Jacobs...Laboratory Oceanography Division Stennis Space Center, MS 39529-5004 NRL/MR/7320--17-9722 Approved for public release; distribution is unlimited

  3. Global sea level fluctuations and uncertainties through a Wilson cycle based on ocean basin volume reconstructions

    NASA Astrophysics Data System (ADS)

    Wright, Nicky; Seton, Maria; Williams, Simon E.; Dietmar Müller, R.

    2017-04-01

    Variations in the volume of ocean basins is the main driving force for (long-wavelength) changes in eustatic sea level in an ice-free world, i.e. most of the Mesozoic and Cenozoic. The volume of ocean basins is largely dependent on changes in the seafloor spreading history, which can be reconstructed based on an age-depth relationship for oceanic crust and an underlying global plate kinematic model. Ocean basin volume reconstructions need to include: (1) a predicted history of back-arc basin formation, including where geological evidence exists for the opening and closing of back-arc basins within a single Wilson cycle, (2) the emplacement and subsidence of oceanic plateaus (LIPs), (3) variations in sediment thickness through time, and (4) a reconstruction of the depth of continental margins and fragments. Unfortunately, due to subduction of oceanic crust, we must rely on synthetically modelled ocean crust for much of Earth's history, for which it is impossible to ground truth the history of LIPs and sediment thickness. In order to improve reconstructions of sea level on geologic time scales and assess the uncertainty in deriving the volume of ocean basins based on a global plate kinematic model, we investigate the influence of these poorly constrained features (e.g. LIPs, back-arc basins, sediment thickness, passive margins) on ocean basin volume since 230 Ma (i.e. throughout an entire Wilson cycle). We assess the characteristics for each feature at present-day and during well-constrained times during the Cenozoic, and create suites of alternative paleobathymetry grids which incorporate varying degrees of each feature's influence. Further, we derive a global sea level curve based only on the reconstruction of ocean basin volume (i.e. excluding effects such as dynamic topography and glaciation), and present the influence of each component and their uncertainties through time. We find that by incorporating reasonable predictions for these components during times

  4. New Community Education Program on Oceans and Global Climate Change: Results from Our Pilot Year

    NASA Astrophysics Data System (ADS)

    Bruno, B. C.; Wiener, C.

    2010-12-01

    Ocean FEST (Families Exploring Science Together) engages elementary school students and their parents and teachers in hands-on science. Through this evening program, we educate participants about ocean and earth science issues that are relevant to their local communities. In the process, we hope to inspire more underrepresented students, including Native Hawaiians, Pacific Islanders and girls, to pursue careers in the ocean and earth sciences. Hawaii and the Pacific Islands will be disproportionately affected by the impacts of global climate change, including rising sea levels, coastal erosion, coral reef degradation and ocean acidification. It is therefore critically important to train ocean and earth scientists within these communities. This two-hour program explores ocean properties and timely environmental topics through six hands-on science activities. Activities are designed so students can see how globally important issues (e.g., climate change and ocean acidification) have local effects (e.g., sea level rise, coastal erosion, coral bleaching) which are particularly relevant to island communities. The Ocean FEST program ends with a career component, drawing parallel between the program activities and the activities done by "real scientists" in their jobs. The take-home message is that we are all scientists, we do science every day, and we can choose to do this as a career. Ocean FEST just completed our pilot year. During the 2009-2010 academic year, we conducted 20 events, including 16 formal events held at elementary schools and 4 informal outreach events. Evaluation data were collected at all formal events. Formative feedback from adult participants (parents, teachers, administrators and volunteers) was solicited through written questionnaires. Students were invited to respond to a survey of five questions both before and after the program to see if there were any changes in content knowledge and career attitudes. In our presentation, we will present our

  5. The ocean quasi-homogeneous layer model and global cycle of carbon dioxide in system of atmosphere-ocean

    NASA Astrophysics Data System (ADS)

    Glushkov, Alexander; Glushkov, Alexander; Loboda, Nataliya; Khokhlov, Valery; Serbov, Nikoly; Svinarenko, Andrey

    The purpose of this paper is carrying out the detailed model of the CO2 global turnover in system of "atmosphere-ocean" with using the ocean quasi-homogeneous layer model. Practically all carried out models are functioning in the average annual regime and accounting for the carbon distribution in bio-sphere in most general form (Glushkov et al, 2003). We construct a modified model for cycle of the carbon dioxide, which allows to reproduce a season dynamics of carbon turnover in ocean with account of zone ocean structure (up quasi-homogeneous layer, thermocline and deepest layer). It is taken into account dependence of the CO2 transfer through the bounder between atmosphere and ocean upon temperature of water and air, wind velocity, buffer mechanism of the CO2 dissolution. The same program is realized for atmosphere part of whole system. It is obtained a tempo-ral and space distribution for concentration of non-organic carbon in ocean, partial press of dissolute CO2 and value of exchange on the border between atmosphere and ocean. It is estimated a role of the wind intermixing of the up ocean layer. The increasing of this effect leads to increasing the plankton mass and further particles, which are transferred by wind, contribute to more quick immersion of microscopic shells and organic material. It is fulfilled investigation of sen-sibility of the master differential equations system solutions from the model parameters. The master differential equa-tions system, describing a dynamics of the CO2 cycle, is numerically integrated by the four order Runge-Cutt method under given initial values of valuables till output of solution on periodic regime. At first it is indicated on possible real-zation of the chaos scenario in system. On our data, the difference of the average annual values for the non-organic car-bon concentration in the up quasi-homogeneous layer between equator and extreme southern zone is 0.15 mol/m3, be-tween the equator and extreme northern zone is 0

  6. Fine-Resolution Satellite-Based Daily Sea Surface Temperatures over the Global Ocean

    DTIC Science & Technology

    2007-05-01

    MODAS with latitudinal extent limited to ±80. Note that only the RTG product includes SST in the Caspian Sea and the Sea of Azov . The plot masks SST...Fine-resolution satellite-based daily sea surface temperatures over the global ocean A. B. Kara1 and C. N. Barron1 Received 18 November 2006; revised...13 February 2007; accepted 27 February 2007; published 22 May 2007. [1] The accuracy and relative merits of two sets of daily global sea surface

  7. Ocean Depths: The Mesopelagic and Implications for Global Warming.

    PubMed

    Costello, Mark J; Breyer, Sean

    2017-01-09

    The mesopelagic or 'twilight zone' of the oceans occurs too deep for photosynthesis, but is a major part of the world's carbon cycle. Depth boundaries for the mesopelagic have now been shown on a global scale using the distribution of pelagic animals detected by compiling echo-soundings from ships around the world, and been used to predict the effect of global warming on regional fish production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Global streamflows Part 2: Reservoir storage yield performance

    NASA Astrophysics Data System (ADS)

    McMahon, Thomas A.; Vogel, Richard M.; Pegram, Geoffrey G. S.; Peel, Murray C.; Etkin, Derek

    2007-12-01

    SummaryThis is the second of three papers describing hydrologic analyses of monthly and annual streamflow data for a global set of 729 unregulated rivers with at least 25 years of continuous data. Capacity estimates of hypothetical reservoirs are computed for each river using the Sequent Peak Algorithm (SPA), Behaviour analysis and the Gould-Dincer Gamma procedure. Based on SPA and Behaviour procedures, empirical relationships relating reservoir capacity and yield were developed which accounted for 87-96% of the variance in capacity estimates across the global data set of monthly streamflows. The theoretical Gould-Dincer Gamma procedure was also shown to be a suitable technique to estimate reservoir capacity-yield relationships. It is noted that the three procedures are based on different definitions of supply reliability. Continental variations of the estimated capacities under equivalent conditions are examined. Reservoir performance measures - reliability, resilience and dimensionless vulnerability - are computed and their continental variations described. As a result of these analyses a number of differences are noted about the performance of reservoirs across continental regions. For example, the median continental reservoir capacity as a ratio of the mean annual flow varied by a factor of 9 across the continental regions. Furthermore, based on the reliability metric as an example of reservoir performance, high reliabilities occur in the South Pacific and Europe, slightly less reliable systems in North and South America, lower still in northern Africa, followed by Australia and the lowest value in southern Africa. This distribution follows inversely with the coefficient of variation of annual streamflow between continents.

  9. Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data.

    PubMed

    Ganachaud, A; Wunsch, C

    2000-11-23

    Through its ability to transport large amounts of heat, fresh water and nutrients, the ocean is an essential regulator of climate. The pathways and mechanisms of this transport and its stability are critical issues in understanding the present state of climate and the possibilities of future changes. Recently, global high-quality hydrographic data have been gathered in the World Ocean Circulation Experiment (WOCE), to obtain an accurate picture of the present circulation. Here we combine the new data from high-resolution trans-oceanic sections and current meters with climatological wind fields, biogeochemical balances and improved a priori error estimates in an inverse model, to improve estimates of the global circulation and heat fluxes. Our solution resolves globally vertical mixing across surfaces of equal density, with coefficients in the range (3-12) x 10(-4) m2 s(-1). Net deep-water production rates amount to (15 +/- 12) x 10(6) m3 s(-1) in the North Atlantic Ocean and (21 +/- 6) x 10(6) m3 s(-1) in the Southern Ocean. Our estimates provide a new reference state for future climate studies with rigorous estimates of the uncertainties.

  10. The role of Pacific Trade Wind trends in driving ocean heat uptake and global hiatuses

    NASA Astrophysics Data System (ADS)

    Maher, Nicola; England, Matthew; Gupta, Alexander Sen; Spence, Paul

    2015-04-01

    Previous work has noted the importance of the tropical Pacific in modulating global temperatures and in offsetting anthropogenic surface warming over decadal periods. This project investigates the role of Pacific Trade Wind changes in modulating the exchange of heat into and out of the sub-surface tropical Pacific Ocean. In particular, the trade wind acceleration observed since the early 1990's is examined, with a focus on ocean heat uptake dynamics associated with phase changes of the Interdecadal Pacific Oscillation (IPO). A number of simulations are performed in an eddy-permitting global ocean model (MOM5) coupled to a sea ice model (SIS). To examine the recent period, the ocean model is forced with atmospheric CORE normal year forcing, with the observed Pacific wind trend from 1992-2013 superimposed linearly over the tropical Pacific region. The role of seasonally varying wind trends is further investigated by running a second experiment with seasonally varying wind anomalies added in the Pacific. To investigate how and when the subducted heat might re-surfaces from the ocean interior in the future, additional experiments are performed that include a ramp down of the trade winds under a variety of scenarios to mimic a future phase change in the IPO. This work has implications for decadal predictions of future global climate change.

  11. Tropical Ocean and Global Atmosphere (TOGA) heat exchange project: A summary report

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Niiler, P. P.

    1985-01-01

    A pilot data center to compute ocean atmosphere heat exchange over the tropical ocean is prposed at the Jet Propulsion Laboratory (JPL) in response to the scientific needs of the Tropical Ocean and Global Atmosphere (TOGA) Program. Optimal methods will be used to estimate sea surface temperature (SET), surface wind speed, and humidity from spaceborne observations. A monthly summary of these parameters will be used to compute ocean atmosphere latent heat exchanges. Monthly fields of surface heat flux over tropical oceans will be constructed using estimations of latent heat exchanges and short wave radiation from satellite data. Verification of all satellite data sets with in situ measurements at a few locations will be provided. The data center will be an experimental active archive where the quality and quantity of data required for TOGA flux computation are managed. The center is essential to facilitate the construction of composite data sets from global measurements taken from different sensors on various satellites. It will provide efficient utilization and easy access to the large volume of satellite data available for studies of ocean atmosphere energy exchanges.

  12. Light penetration structures the deep acoustic scattering layers in the global ocean.

    PubMed

    Aksnes, Dag L; Røstad, Anders; Kaartvedt, Stein; Martinez, Udane; Duarte, Carlos M; Irigoien, Xabier

    2017-05-01

    The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring the pelagic open ocean ecosystem. It is formed by mesopelagic fishes and pelagic invertebrates. The DSL animals are an important food source for marine megafauna and contribute to the biological carbon pump through the active flux of organic carbon transported in their daily vertical migrations. They occupy depths from 200 to 1000 m at daytime and migrate to a varying degree into surface waters at nighttime. Their daytime depth, which determines the migration amplitude, varies across the global ocean in concert with water mass properties, in particular the oxygen regime, but the causal underpinning of these correlations has been unclear. We present evidence that the broad variability in the oceanic DSL daytime depth observed during the Malaspina 2010 Circumnavigation Expedition is governed by variation in light penetration. We find that the DSL depth distribution conforms to a common optical depth layer across the global ocean and that a correlation between dissolved oxygen and light penetration provides a parsimonious explanation for the association of shallow DSL distributions with hypoxic waters. In enhancing understanding of this phenomenon, our results should improve the ability to predict and model the dynamics of one of the largest animal biomass components on earth, with key roles in the oceanic biological carbon pump and food web.

  13. A Global Ocean Circulation Model based on a Mimetic Discretization Approach

    NASA Astrophysics Data System (ADS)

    Korn, Peter

    2015-04-01

    The new general circulation model of the global ocean ICON-O is introduced. ICON-O based on the Ocean Primitive Equations: the incompressible Navier-Stokes Equations in vector invariant form with a free surface plus the hydrostatic and the Boussinesq approximation. The model solves the ocean primitive equations on a triangular icosahedral grid with C-type staggering. The models dynamical core as well as its parametrizations such as the mesoscale eddy parametrization of Gent-McWilliams use a coherent discretization that is based on a mimetic discretization approach. We describe the new disretization and some of its properties. A sequence of simulations is presented that range from idealized process studies to long-term global ocean simulations. The Max Planck Institute for Meteorology and the German Weather Service have been collaborating through the ICON project to develop new coupled atmosphere-ocean general circulation models for climate research and numerical weather forecasting. The model ICON-O is the ocean component of the ICON modeling system.

  14. Time-domain modeling of global ocean tides generated by the full lunisolar potential

    NASA Astrophysics Data System (ADS)

    Einšpigel, David; Martinec, Zdeněk

    2017-02-01

    Traditionally, ocean tides have been modeled in frequency domain with a forcing from selected tidal constituents. It is a natural approach; however, it implicitly neglects non-linearities of ocean dynamics. An alternative approach is time-domain modeling with a forcing given by the full lunisolar potential, i.e., all tidal waves are a priori included. This approach has been applied in several ocean tide models; however, some challenging tasks still remain, for example, assimilation of satellite altimetry data. In this paper, we introduce the assimilative scheme applicable in a time-domain model, which is an alternative to existing techniques used in assimilative ocean tide models. We present results from DEBOT, a global barotropic ocean tide model, which has two modes: DEBOT-h, a purely hydrodynamical mode, and DEBOT-a, an assimilative mode. The accuracy of DEBOT in both modes is assessed through a series of tests against tide gauge data which demonstrate that DEBOT is comparable to state-of-the-art global ocean tide models for major tidal constituents. Furthermore, as signals of all tidal frequencies are included in DEBOT, we also discuss modeling of minor tidal constituents and non-linear compound tides. Our modeling approach can be useful for those applications where the frequency domain approach is not suitable.

  15. Distinct global warming rates tied to multiple ocean surface temperature changes

    NASA Astrophysics Data System (ADS)

    Yao, Shuai-Lei; Luo, Jing-Jia; Huang, Gang; Wang, Pengfei

    2017-07-01

    The globally averaged surface temperature has shown distinct multi-decadal fluctuations since 1900, characterized by two weak slowdowns in the mid-twentieth century and early twenty-first century and two strong accelerations in the early and late twentieth century. While the recent global warming (GW) hiatus has been particularly ascribed to the eastern Pacific cooling, causes of the cooling in the mid-twentieth century and distinct intensity differences between the slowdowns and accelerations remain unclear. Here, our model experiments with multiple ocean sea surface temperature (SST) forcing reveal that, although the Pacific SSTs play essential roles in the GW rates, SST changes in other basins also exert vital influences. The mid-twentieth-century cooling results from the SST cooling in the tropical Pacific and Atlantic, which is partly offset by the Southern Ocean warming. During the recent hiatus, the tropical Pacific-induced strong cooling is largely compensated by warming effects of other oceans. In contrast, during the acceleration periods, ubiquitous SST warming across all the oceans acts jointly to exaggerate the GW. Multi-model simulations with separated radiative forcing suggest diverse causes of the SST changes in multiple oceans during the GW acceleration and slowdown periods. Our results highlight the importance of multiple oceans on the multi-decadal GW rates.

  16. Light penetration structures the deep acoustic scattering layers in the global ocean

    PubMed Central

    Aksnes, Dag L.; Røstad, Anders; Kaartvedt, Stein; Martinez, Udane; Duarte, Carlos M.; Irigoien, Xabier

    2017-01-01

    The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring the pelagic open ocean ecosystem. It is formed by mesopelagic fishes and pelagic invertebrates. The DSL animals are an important food source for marine megafauna and contribute to the biological carbon pump through the active flux of organic carbon transported in their daily vertical migrations. They occupy depths from 200 to 1000 m at daytime and migrate to a varying degree into surface waters at nighttime. Their daytime depth, which determines the migration amplitude, varies across the global ocean in concert with water mass properties, in particular the oxygen regime, but the causal underpinning of these correlations has been unclear. We present evidence that the broad variability in the oceanic DSL daytime depth observed during the Malaspina 2010 Circumnavigation Expedition is governed by variation in light penetration. We find that the DSL depth distribution conforms to a common optical depth layer across the global ocean and that a correlation between dissolved oxygen and light penetration provides a parsimonious explanation for the association of shallow DSL distributions with hypoxic waters. In enhancing understanding of this phenomenon, our results should improve the ability to predict and model the dynamics of one of the largest animal biomass components on earth, with key roles in the oceanic biological carbon pump and food web. PMID:28580419

  17. Global variability and changes in ocean total alkalinity from Aquarius satellite data

    NASA Astrophysics Data System (ADS)

    Fine, Rana A.; Willey, Debra A.; Millero, Frank J.

    2017-01-01

    This work demonstrates how large-scale Aquarius satellite salinity data have provided an unprecedented opportunity when combined with total alkalinity (TA) equations as a function of salinity and temperature to examine global changes in the CO2 system. Alkalinity is a gauge on the ability of seawater to neutralize acids. TA correlates strongly with salinity. Spatial variability in alkalinity and salinity exceed temporal variability. Northern Hemisphere has more spatial variability in TA and salinity, while less variability in Southern Ocean TA is due to less salinity variability and upwelling of waters enriched in alkalinity. For the first time it is shown that TA in subtropical regions has increased as compared with climatological data; this is reflective of large-scale changes in the global water cycle. Thus, as temperature and salinity increase in subtropical regions, the resultant increase in TA and ocean acidification is reinforcing that from oceanic uptake of atmospheric CO2.

  18. Industrial-era global ocean heat uptake doubles in recent decades

    NASA Astrophysics Data System (ADS)

    Gleckler, Peter J.; Durack, Paul J.; Stouffer, Ronald J.; Johnson, Gregory C.; Forest, Chris E.

    2016-04-01

    Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0-700 m) ocean. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes identified in observational, modelling and data re-analysis studies. Here, we examine OHC changes in the context of the Earth’s global energy budget since early in the industrial era (circa 1865-2015) for a range of depths. We rely on OHC change estimates from a diverse collection of measurement systems including data from the nineteenth-century Challenger expedition, a multi-decadal record of ship-based in situ mostly upper-ocean measurements, the more recent near-global Argo floats profiling to intermediate (2,000 m) depths, and full-depth repeated transoceanic sections. We show that the multi-model mean constructed from the current generation of historically forced climate models is consistent with the OHC changes from this diverse collection of observational systems. Our model-based analysis suggests that nearly half of the industrial-era increases in global OHC have occurred in recent decades, with over a third of the accumulated heat occurring below 700 m and steadily rising.

  19. Preface to special issue (Impacts of surface ocean acidification in polar seas and globally: A field-based approach)

    NASA Astrophysics Data System (ADS)

    Tyrrell, Toby; Tarling, Geraint A.; Leakey, Raymond J. G.; Cripps, Gemma; Thorpe, Sally; Richier, Sophie; Mark Moore, C.

    2016-05-01

    Both ocean acidification and global warming are consequences of the rise in atmospheric CO2. Ocean acidification is not itself a consequence of global warming, but rather of the invasion of atmospheric CO2 into the ocean. Time-series of carbonate chemistry measurements in different locations around the world all document the continuous and ongoing increase in the amount of CO2 in the ocean, and the consequential accompanying decrease in surface ocean seawater pH at all sites over the last years (Bates et al., 2014).

  20. Recent Short Term Global Aerosol Trends over Land and Ocean Dominated by Biomass Burning

    NASA Technical Reports Server (NTRS)

    Remer, Lorraine A.; Koren, Ilan; Kleidman, RIchard G.; Levy, Robert C.; Martins, J. Vanderlei; Kim, Kyu-Myong; Tanre, Didier; Mattoo, Shana; Yu, Hongbin

    2007-01-01

    NASA's MODIS instrument on board the Terra satellite is one of the premier tools to assess aerosol over land and ocean because of its high quality calibration and consistency. We analyze Terra-MODIS's seven year record of aerosol optical depth (AOD) observations to determine whether global aerosol has increased or decreased during this period. This record shows that AOD has decreased over land and increased over ocean. Only the ocean trend is statistically significant and corresponds to an increase in AOD of 0.009, or a 15% increase from background conditions. The strongest increasing trends occur over regions and seasons noted for strong biomass burning. This suggests that biomass burning aerosol dominates the increasing trend over oceans and mitigates the otherwise mostly negative trend over the continents.

  1. M2, S2, K1 models of the global ocean tide

    NASA Technical Reports Server (NTRS)

    Parke, M. E.; Hendershott, M. C.

    1979-01-01

    Ocean tidal signals appear in many geophysical measurements. Geophysicists need realistic tidal models to aid in interpretation of their data. Because of the closeness to resonance of dissipationless ocean tides, it is difficult for numerical models to correctly represent the actual open ocean tide. As an approximate solution to this problem, test functions derived by solving Laplace's Tidal Equations with ocean loading and self gravitation are used as a basis for least squares dynamic interpolation of coastal and island tidal data for the constituents M2, S2, and Kl. The resulting representations of the global tide are stable over at least a ?5% variation in the mean depth of the model basin, and they conserve mass. Maps of the geocentric tide, the induced free space potential, the induced vertical component of the solid earth tide, and the induced vertical component of the gravitational field for each contituent are presented.

  2. Oceanic carbon dioxide uptake in a model of century-scale global warming

    SciTech Connect

    Sarmiento, J.L.; Le Quere, C.

    1996-11-22

    In a model of ocean-atmosphere interaction that excluded biological processes, the oceanic uptake of atmospheric carbon dioxide (CO{sub 2}) was substantially reduced in scenarios involving global warming relative to control scenarios. The primary reason for the reduced uptake was the weakening or collapse of the ocean thermohaline circulation. Such a large reduction in this ocean uptake would have a major impact o the future growth rate of atmospheric CO{sub 2}. Model simulations that include a simple representation of biological processes show a potentially large offsetting effect resulting from the downward flux of biogenic carbon. However, the magnitude of the offset is difficult to quantify with present knowledge. 19 refs., 3 figs., 2 tabs.

  3. The CONCEPTS Global Ice-Ocean Prediction System: Establishing an Environmental Prediction Capability in Canada

    NASA Astrophysics Data System (ADS)

    Pellerin, Pierre; Smith, Gregory; Testut, Charles-Emmanuel; Surcel Colan, Dorina; Roy, Francois; Reszka, Mateusz; Dupont, Frederic; Lemieux, Jean-Francois; Beaudoin, Christiane; He, Zhongjie; Belanger, Jean-Marc; Deacu, Daniel; Lu, Yimin; Buehner, Mark; Davidson, Fraser; Ritchie, Harold; Lu, Youyu; Drevillon, Marie; Tranchant, Benoit; Garric, Gilles

    2015-04-01

    Here we describe a new system implemented recently at the Canadian Meteorological Centre (CMC) entitled the Global Ice Ocean Prediction System (GIOPS). GIOPS provides ice and ocean analyses and 10 day forecasts daily at 00GMT on a global 1/4° resolution grid. GIOPS includes a full multivariate ocean data assimilation system that combines satellite observations of sea level anomaly and sea surface temperature (SST) together with in situ observations of temperature and salinity. In situ observations are obtained from a variety of sources including: the Argo network of autonomous profiling floats, moorings, ships of opportunity, marine mammals and research cruises. Ocean analyses are blended with sea ice analyses produced by the Global Ice Analysis System.. GIOPS has been developed as part of the Canadian Operational Network of Coupled Environmental PredicTion Systems (CONCEPTS) tri-departmental initiative between Environment Canada, Fisheries and Oceans Canada and National Defense. The development of GIOPS was made through a partnership with Mercator-Océan, a French operational oceanography group. Mercator-Océan provided the ocean data assimilation code and assistance with the system implementation. GIOPS has undergone a rigorous evaluation of the analysis, trial and forecast fields demonstrating its capacity to provide high-quality products in a robust and reliable framework. In particular, SST and ice concentration forecasts demonstrate a clear benefit with respect to persistence. These results support the use of GIOPS products within other CMC operational systems, and more generally, as part of a Government of Canada marine core service. Impact of a two-way coupling between the GEM atmospheric model and NEMO-CICE ocean-ice model will also be presented.

  4. Twenty Years of Progress on Global Ocean Tides: The Impact of Satellite Altimetry

    NASA Technical Reports Server (NTRS)

    Egbert, Gary; Ray, Richard

    2012-01-01

    At the dawn of the era of high-precision altimetry, before the launch of TOPEX/Poseidon, ocean tides were properly viewed as a source of noise--tidal variations in ocean height would represent a very substantial fraction of what the altimeter measures, and would have to be accurately predicted and subtracted if altimetry were to achieve its potential for ocean and climate studies. But to the extent that the altimetry could be severely contaminated by tides, it also represented an unprecedented global-scale tidal data set. These new data, together with research stimulated by the need for accurate tidal corrections, led to a renaissance in tidal studies in the oceanographic community. In this paper we review contributions of altimetry to tidal science over the past 20 years, emphasizing recent progress. Mapping of tides has now been extended from the early focus on major constituents in the open ocean to include minor constituents, (e.g., long-period tides; non-linear tides in shelf waters, and in the open ocean), and into shallow and coastal waters. Global and spatially local estimates of tidal energy balance have been refined, and the role of internal tide conversion in dissipating barotropic tidal energy is now well established through modeling, altimetry, and in situ observations. However, energy budgets for internal tides, and the role of tidal dissipation in vertical ocean mixing remain controversial topics. Altimetry may contribute to resolving some of these important questions through improved mapping of low-mode internal tides. This area has advanced significantly in recent years, with several global maps now available, and progress on constraining temporally incoherent components. For the future, new applications of altimetry (e.g., in the coastal ocean, where barotropic tidal models remain inadequate), and new mission concepts (studies of the submesoscale with SWOT, which will require correction for internal tides) may bring us full circle, again pushing

  5. Oceanic Fluxes of Mass, Heat and Freshwater: A Global Estimate and Perspective

    NASA Technical Reports Server (NTRS)

    MacDonald, Alison Marguerite

    1995-01-01

    Data from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional heat and freshwater budgets and are used to examine the sensitivity of the global circulation, both inter and intra-basin exchange rates, to a variety of external constraints provided by estimates of Ekman, boundary current and throughflow transports. A solution is found which is consistent with both the model physics and the global data set, despite a twenty five year time span and a lack of seasonal consistency among the data. The overall pattern of the global circulation suggested by the models is similar to that proposed in previously published local studies and regional reviews. However, significant qualitative and quantitative differences exist. These differences are due both to the model definition and to the global nature of the data set.

  6. Oceanic Fluxes of Mass, Heat and Freshwater: A Global Estimate and Perspective

    NASA Technical Reports Server (NTRS)

    MacDonald, Alison Marguerite

    1995-01-01

    Data from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional heat and freshwater budgets and are used to examine the sensitivity of the global circulation, both inter and intra-basin exchange rates, to a variety of external constraints provided by estimates of Ekman, boundary current and throughflow transports. A solution is found which is consistent with both the model physics and the global data set, despite a twenty five year time span and a lack of seasonal consistency among the data. The overall pattern of the global circulation suggested by the models is similar to that proposed in previously published local studies and regional reviews. However, significant qualitative and quantitative differences exist. These differences are due both to the model definition and to the global nature of the data set.

  7. A 1/16° eddying simulation of the global NEMO sea-ice-ocean system

    NASA Astrophysics Data System (ADS)

    Iovino, Doroteaciro; Masina, Simona; Storto, Andrea; Cipollone, Andrea; Stepanov, Vladimir N.

    2016-08-01

    Analysis of a global eddy-resolving simulation using the NEMO general circulation model is presented. The model has 1/16° horizontal spacing at the Equator, employs two displaced poles in the Northern Hemisphere, and uses 98 vertical levels. The simulation was spun up from rest and integrated for 11 model years, using ERA-Interim reanalysis as surface forcing. Primary intent of this hindcast is to test how the model represents upper ocean characteristics and sea ice properties. Analysis of the zonal averaged temperature and salinity, and the mixed layer depth indicate that the model average state is in good agreement with observed fields and that the model successfully represents the variability in the upper ocean and at intermediate depths. Comparisons against observational estimates of mass transports through key straits indicate that most aspects of the model circulation are realistic. As expected, the simulation exhibits turbulent behaviour and the spatial distribution of the sea surface height (SSH) variability from the model is close to the observed pattern. The distribution and volume of the sea ice are, to a large extent, comparable to observed values. Compared with a corresponding eddy-permitting configuration, the performance of the model is significantly improved: reduced temperature and salinity biases, in particular at intermediate depths, improved mass and heat transports, better representation of fluxes through narrow and shallow straits, and increased global-mean eddy kinetic energy (by ˜ 40 %). However, relatively minor weaknesses still exist such as a lower than observed magnitude of the SSH variability. We conclude that the model output is suitable for broader analysis to better understand upper ocean dynamics and ocean variability at global scales. This simulation represents a major step forward in the global ocean modelling at the Euro-Mediterranean Centre on Climate Change and constitutes the groundwork for future applications to short

  8. Seven-Year SSM/I-Derived Global Ocean Surface Turbulent Fluxes