;Agreement; in the IPCC Confidence measure

NASA Astrophysics Data System (ADS)

Rehg, William; Staley, Kent

2017-02-01

The Intergovernmental Panel on Climate Change (IPCC) has, in its most recent Assessment Report (AR5), articulated guidelines for evaluating and communicating uncertainty that include a qualitative scale of confidence. We examine one factor included in that scale: the "degree of agreement." Some discussions of the degree of agreement in AR5 suggest that the IPCC is employing a consensus-oriented social epistemology. We consider the application of the degree of agreement factor in practice in AR5. Our findings, though based on a limited examination, suggest that agreement attributions do not so much track the overall consensus among investigators as the degree to which relevant research findings substantively converge in offering support for IPCC claims. We articulate a principle guiding confidence attributions in AR5 that centers not on consensus but on the notion of support. In concluding, we tentatively suggest a pluralist approach to the notion of support.

The Equatorial Pacific Cold Tongue Simulated by IPCC AR4 Coupled GCMs: Upper Ocean Heat Budget and Feedback Analysis

DTIC Science & Technology

2012-05-15

ET AL .: THE PACIFIC COLD TONGUE BIAS ANALYSIS C05024 circulation, which intensifies the surface easterly winds over the Pacific Basin, further...productivity, and in carbon cycling since it is the major oceanic source of C02 for the atmosphere [Field et al , 1998; Calvo et al , 2011]. Large SST anomalies...used for climate predictions and projec- tions [Neelin et al , 1992; Mechoso et al , 1995; Delecluse et al , 1998; Laufet al , 2001; Davey

Influences of Regional Climate Change on Air Quality Across the Continental U.S. Projected from Downscaling IPCC AR5 Simulations. Chapter 2

NASA Technical Reports Server (NTRS)

Nolte, Christopher; Otte, Tanya; Pinder, Robert; Bowden, J.; Herwehe, J.; Faluvegi, Gregory; Shindell, Drew

2013-01-01

Projecting climate change scenarios to local scales is important for understanding, mitigating, and adapting to the effects of climate change on society and the environment. Many of the global climate models (GCMs) that are participating in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) do not fully resolve regional-scale processes and therefore cannot capture regional-scale changes in temperatures and precipitation. We use a regional climate model (RCM) to dynamically downscale the GCM's large-scale signal to investigate the changes in regional and local extremes of temperature and precipitation that may result from a changing climate. In this paper, we show preliminary results from downscaling the NASA/GISS ModelE IPCC AR5 Representative Concentration Pathway (RCP) 6.0 scenario. We use the Weather Research and Forecasting (WRF) model as the RCM to downscale decadal time slices (1995-2005 and 2025-2035) and illustrate potential changes in regional climate for the continental U.S. that are projected by ModelE and WRF under RCP6.0. The regional climate change scenario is further processed using the Community Multiscale Air Quality modeling system to explore influences of regional climate change on air quality.

The Contribution of Agriculture, Forestry and other Land Use activities to Global Warming, 1990-2012.

PubMed

Tubiello, Francesco N; Salvatore, Mirella; Ferrara, Alessandro F; House, Jo; Federici, Sandro; Rossi, Simone; Biancalani, Riccardo; Condor Golec, Rocio D; Jacobs, Heather; Flammini, Alessandro; Prosperi, Paolo; Cardenas-Galindo, Paola; Schmidhuber, Josef; Sanz Sanchez, Maria J; Srivastava, Nalin; Smith, Pete

2015-01-10

We refine the information available through the IPCC AR5 with regard to recent trends in global GHG emissions from agriculture, forestry and other land uses (AFOLU), including global emission updates to 2012. Using all three available AFOLU datasets employed for analysis in the IPCC AR5, rather than just one as done in the IPCC AR5 WGIII Summary for Policy Makers, our analyses point to a down-revision of global AFOLU shares of total anthropogenic emissions, while providing important additional information on subsectoral trends. Our findings confirm that the share of AFOLU emissions to the anthropogenic total declined over time. They indicate a decadal average of 28.7 ± 1.5% in the 1990s and 23.6 ± 2.1% in the 2000s and an annual value of 21.2 ± 1.5% in 2010. The IPCC AR5 had indicated a 24% share in 2010. In contrast to previous decades, when emissions from land use (land use, land use change and forestry, including deforestation) were significantly larger than those from agriculture (crop and livestock production), in 2010 agriculture was the larger component, contributing 11.2 ± 0.4% of total GHG emissions, compared to 10.0 ± 1.2% of the land use sector. Deforestation was responsible for only 8% of total anthropogenic emissions in 2010, compared to 12% in the 1990s. Since 2010, the last year assessed by the IPCC AR5, new FAO estimates indicate that land use emissions have remained stable, at about 4.8 Gt CO 2 eq yr -1 in 2012. Emissions minus removals have also remained stable, at 3.2 Gt CO 2 eq yr -1 in 2012. By contrast, agriculture emissions have continued to grow, at roughly 1% annually, and remained larger than the land use sector, reaching 5.4 Gt CO 2 eq yr -1 in 2012. These results are useful to further inform the current climate policy debate on land use, suggesting that more efforts and resources should be directed to further explore options for mitigation in agriculture, much in line with the large efforts devoted to REDD+ in the past decade. © 2015 John Wiley & Sons Ltd.

Comparative evaluation of the IPCC AR5 CMIP5 versus the AR4 CMIP3 model ensembles for regional precipitation and their extremes over South America

NASA Astrophysics Data System (ADS)

Tolen, J.; Kodra, E. A.; Ganguly, A. R.

2011-12-01

The assertion that higher-resolution experiments or more sophisticated process models within the IPCC AR5 CMIP5 suite of global climate model ensembles improves precipitation projections over the IPCC AR4 CMIP3 suite remains a hypothesis that needs to be rigorously tested. The questions are particularly important for local to regional assessments at scales relevant for the management of critical infrastructures and key resources, particularly for the attributes of sever precipitation events, for example, the intensity, frequency and duration of extreme precipitation. Our case study is South America, where precipitation and their extremes play a central role in sustaining natural, built and human systems. To test the hypothesis that CMIP5 improves over CMIP3 in this regard, spatial and temporal measures of prediction skill are constructed and computed by comparing climate model hindcasts with the NCEP-II reanalysis data, considered here as surrogate observations, for the entire globe and for South America. In addition, gridded precipitation observations over South America based on rain gage measurements are considered. The results suggest that the utility of the next-generation of global climate models over the current generation needs to be carefully evaluated on a case-by-case basis before communicating to resource managers and policy makers.

Methods for Assessing Uncertainties in Climate Change, Impacts and Responses (Invited)

NASA Astrophysics Data System (ADS)

Manning, M. R.; Swart, R.

2009-12-01

Assessing the scientific uncertainties or confidence levels for the many different aspects of climate change is particularly important because of the seriousness of potential impacts and the magnitude of economic and political responses that are needed to mitigate climate change effectively. This has made the treatment of uncertainty and confidence a key feature in the assessments carried out by the Intergovernmental Panel on Climate Change (IPCC). Because climate change is very much a cross-disciplinary area of science, adequately dealing with uncertainties requires recognition of their wide range and different perspectives on assessing and communicating those uncertainties. The structural differences that exist across disciplines are often embedded deeply in the corresponding literature that is used as the basis for an IPCC assessment. The assessment of climate change science by the IPCC has from its outset tried to report the levels of confidence and uncertainty in the degree of understanding in both the underlying multi-disciplinary science and in projections for future climate. The growing recognition of the seriousness of this led to the formation of a detailed approach for consistent treatment of uncertainties in the IPCC’s Third Assessment Report (TAR) [Moss and Schneider, 2000]. However, in completing the TAR there remained some systematic differences between the disciplines raising concerns about the level of consistency. So further consideration of a systematic approach to uncertainties was undertaken for the Fourth Assessment Report (AR4). The basis for the approach used in the AR4 was developed at an expert meeting of scientists representing many different disciplines. This led to the introduction of a broader way of addressing uncertainties in the AR4 [Manning et al., 2004] which was further refined by lengthy discussions among many IPCC Lead Authors, for over a year, resulting in a short summary of a standard approach to be followed for that assessment [IPCC, 2005]. This paper extends a review of the treatment of uncertainty in the IPCC assessments by Swart et al [2009]. It is shown that progress towards consistency has been made but that there also appears to be a need for continued use of several complementary approaches in order to cover the wide range of circumstances across different disciplines involved in climate change. While this reflects the situation in the science community, it also raises the level of complexity for policymakers and other users of the assessments who would prefer one common consensus approach. References IPCC (2005), Guidance Notes for Lead Authors of the IPCC Fourth Assessment Report on Addressing Uncertainties, IPCC, Geneva. Manning, M., et al. (2004), IPCC Workshop on Describing Scientific Uncertainties in Climate Change to Support Analysis of Risk and of Options. IPCC Moss, R., and S. Schneider (2000), Uncertainties, in Guidance Papers on the Cross Cutting Issues of the Third Assessment Report of the IPCC, edited by R. Pachauri, et al., Intergovernmental Panel on Climate Change (IPCC), Geneva. Swart, R., et al. (2009), Agreeing to disagree: uncertainty management in assessing climate change, impacts and responses by the IPCC Climatic Change, 92(1-2), 1 - 29.

Problems with the North American Monsoon in CMIP/IPCC GCM Precipitation

NASA Astrophysics Data System (ADS)

Schiffer, N. J.; Nesbitt, S. W.

2011-12-01

Successful water management in the Desert Southwest and surrounding areas hinges on anticipating the timing and distribution of precipitation. IPCC AR4 models predict a more arid climate, more extreme precipitation events, and an earlier peak in springtime streamflow in the North American Monsoon region as the area warms. This study aims to assess the summertime skill with which general circulation models (GCMs) simulate precipitation and related dynamics over this region, a necessary precursor to reliable hydroclimate projections. Thirty-year climatologies of several GCMs in the third and fifth Climate Model Intercomparison Projects (CMIP) are statistically evaluated against each other and observed climatology for their skill in representing the location, timing, variability, character, and large-scale forcing of precipitation over the southwestern United States and northwestern Mexico. The results of this study will lend greater credence to more detailed, higher resolution studies, based on the CMIP and IPCC models, of the region's future hydrology. Our ultimate goal is to provide guidance such that decision-makers can plan future water management with more confidence.

Weighting climate model projections using observational constraints.

PubMed

Gillett, Nathan P

2015-11-13

Projected climate change integrates the net response to multiple climate feedbacks. Whereas existing long-term climate change projections are typically based on unweighted individual climate model simulations, as observed climate change intensifies it is increasingly becoming possible to constrain the net response to feedbacks and hence projected warming directly from observed climate change. One approach scales simulated future warming based on a fit to observations over the historical period, but this approach is only accurate for near-term projections and for scenarios of continuously increasing radiative forcing. For this reason, the recent Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) included such observationally constrained projections in its assessment of warming to 2035, but used raw model projections of longer term warming to 2100. Here a simple approach to weighting model projections based on an observational constraint is proposed which does not assume a linear relationship between past and future changes. This approach is used to weight model projections of warming in 2081-2100 relative to 1986-2005 under the Representative Concentration Pathway 4.5 forcing scenario, based on an observationally constrained estimate of the Transient Climate Response derived from a detection and attribution analysis. The resulting observationally constrained 5-95% warming range of 0.8-2.5 K is somewhat lower than the unweighted range of 1.1-2.6 K reported in the IPCC AR5. © 2015 The Authors.

Coupled Long-Term Evolution of Climate and the Greenland Ice Sheet During the Last Interglacial and Implications for the Future

NASA Astrophysics Data System (ADS)

Otto-Bliesner, B. L.; Lofverstrom, M.; Lipscomb, W.; Fyke, J. G.; Marshall, S.; Sacks, B.

2017-12-01

The Greenland Ice Sheet (GrIS) is expected to contribute increasingly to global sea level rise by the end of this century, and potentially several meters in this millennium, but still with considerable uncertainty. The rate of Greenland melt will impact on regional sea levels. The Last Interglacial (LIG, 129 ka to 116 ka) is recognized as an important period for testing our knowledge of climate-ice sheet interactions in warm climate states. Although the LIG was discussed in the First Assessment Report of the IPCC, it gained more prominence in the IPCC Fourth and Fifth Assessment (AR4 and AR5) with reconstructions highlighting that global mean sea level was at least 5 m higher (but probably no more than 10 m higher) than present for several thousand years during the LIG. Model results assessed for the AR5 suggest a sea level contribution of 1.4 to 4.3 m from the GrIS. These model simulations, though, did not include all the feedbacks of the climate system and the GrIS. Here, we examine the response of the Arctic climate system and the GrIS in simulations with the Community Earth System Model (CESM) fully coupled to the Community Ice Sheet Model (CISM), using a surface energy balance scheme and without bias corrections. The analysis focuses on how the GrIS responds to the imposed high boreal summer insolation of the LIG and in addition, to the long-term feedbacks of high-latitude vegetation changes. Results will highlight the evolution of the ice sheet and the surface mass balance (patterns of ablation and accumulation) as compared to data-based reconstructions for the LIG. We conclude with a discussion on how the LIG may be informative as a potential process analogue for the GrIS response for future centuries to come.

Evaluation of cloud fraction and its radiative effect simulated by IPCC AR4 global models against ARM surface observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Yun; Long, Charles N.; Wang, Hailong

2012-02-17

Cloud Fraction (CF) is the dominant modulator of radiative fluxes. In this study, we evaluate CF simulations in the IPCC AR4 GCMs against ARM ground measurements, with a focus on the vertical structure, total amount of cloud and its effect on cloud shortwave transmissivity, for both inter-model deviation and model-measurement discrepancy. Our intercomparisons of three CF or sky-cover related dataset reveal that the relative differences are usually less than 10% (5%) for multi-year monthly (annual) mean values, while daily differences are quite significant. The results also show that the model-observation and the inter-model deviations have a similar magnitude for themore » total CF (TCF) and the normalized cloud effect, and they are twice as large as the surface downward solar radiation and cloud transmissivity. This implies that the other cloud properties, such as cloud optical depth and height, have a similar magnitude of disparity to TCF among the GCMs, and suggests that a better agreement among the GCMs in solar radiative fluxes could be the result of compensating errors in either cloud vertical structure, cloud optical depth or cloud fraction. Similar deviation pattern between inter-model and model-measurement suggests that the climate models tend to generate larger bias against observations for those variables with larger inter-model deviation. The simulated TCF from IPCC AR4 GCMs are very scattered through all seasons over three ARM sites: Southern Great Plains (SGP), Manus, Papua New Guinea and North Slope of Alaska (NSA). The GCMs perform better at SGP than at Manus and NSA in simulating the seasonal variation and probability distribution of TCF; however, the TCF in these models is remarkably underpredicted and cloud transmissivity is less susceptible to the change of TCF than the observed at SGP. Much larger inter-model deviation and model bias are found over NSA than the other sites in estimating the TCF, cloud transmissivity and cloud-radiation interaction, suggesting that the Arctic region continues to challenge cloud simulations in climate models. Most of the GCMs tend to underpredict CF and fail to capture the seasonal variation of CF at middle and low levels in the tropics. The high altitude CF is much larger in the GCMs than the observation and the inter-model variability of CF also reaches maximum at high levels in the tropics. Most of the GCMs tend to underpredict CF by 50-150% relative to the measurement average at low and middle levels over SGP. While the GCMs generally capture the maximum CF in the boundary layer and vertical variability, the inter-model deviation is largest near surface over the Arctic. The internal variability of CF simulated in ensemble runs with the same model is very minimal.« less

Influences of Regional Climate Change on Air Quality across the Continental U.S. Projected from Downscaling IPCC ARS Simulations

EPA Science Inventory

Projecting climate change scenarios to local scales is important for understanding, mitigating, and adapting to the effects of climate change on society and the environment. Many of the global climate models (GCMs) that are participating in the Intergovernmental Panel on Climate ...

Making sense of past climate changes

NASA Astrophysics Data System (ADS)

Masson-Delmotte, Valérie; Schulz, Michael

2014-05-01

This presentation will summarize the paleoclimate perspective in IPCC AR5, which combines information from natural archives, paleoclimate simulations using both the CMIP5 framework and other simulations, model-data comparisons for model evaluation at hemispheric to regional scales, detection - attribution, and process studies throughout timescales such as polar amplification, carbon cycle or sea level change. It will highlight new findings and coordinated efforts which, within the scientific community, have allowed new information to emerge on time for AR5. It will also stress the aspects which could not be covered or assessed as well as suggestions for further inclusion of paleoclimate information to inform projections.

Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

DTIC Science & Technology

2014-05-15

atmospheric fields, including sea level pressure ( SLP ), on daily and sub-daily time scales at 2° horizontal resolution. A higher-resolution and more...its 21st-century simulation. Extreme cyclones were defined as occurrences of daily mean SLP at least 40 hPa below the climatological annual-average... SLP at a grid point. As such, no cyclone-tracking algorithm was employed, because the purpose here is to identify instances of extremely strong

CMIP6 Citation Services and the Data Services of the IPCC Data Distribution Centre for AR6

NASA Astrophysics Data System (ADS)

Stockhause, Martina; Lautenschlager, Michael

2017-04-01

As a result of the experiences from CMIP5 the two services contributed by DKRZ to the CMIP research infrastructure have been improved for CMIP6: the Citation Services and the Services of the IPCC Data Distribution Centre (DDC, http://ipcc-data.org). 1. Data Citation Services: Within CMIP5 it took a couple of years before the data was citable with their DataCite DOIs. The DataCite DOI registration by the WDC Climate at DKRZ (World Data Center Climate at the Climate Computing Center) requires data transfer and long-term archival at DKRZ according to DDC's quality standards. Based on a request from WGCM (Working Group on Climate Models) an additional early citation possibility for the evolving CMIP6 data was added to the citation service (http://cmip6cite.wdc-climate.de). 2. IPCC DDC Services: WDC Climate has been hosting the IPCC DDC's Reference Data Archive for the climate model output underlying the IPCC Assessment Reports (ARs) since the Second Assessment Report in 1995. One task of the DDC is the support of the IPCC Working Groups (WGs) and their authors. The WG support was not sufficient for AR5 resulting in WG I setting up and maintaining their own CMIP5 data repository hosting a data subset. The DDC will open DKRZ's CMIP data pool as an additional DDC service for the IPCC authors using a synergy with the interests of the national climate community. Within the PICO the Citation and the IPCC DDC services will be presented from a user's perspective. The connections to and integration into the infrastructure for CMIP6 (see https://www.earthsystemcog.org/projects/wip/) will be explained.

Climate Change: Issues in the Science and Its Use

DTIC Science & Technology

2009-07-01

7 3. The State of the Climate : Changes since the IPCC AR4...together with a review of the current state of the climate itself that establishes the importance of advancing our understanding. In the interests...common data stewardship and sharing standards. 3. The  State   of   the   Climate : Changes since the IPCC AR4  We assess the state of the climate against the

Fifth IPCC Assessment Report Now Out

NASA Astrophysics Data System (ADS)

Kundzewicz, Zbigniew W.

2014-01-01

The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) is now available. It provides policymakers with an assessment of information on climate change, its impacts and possible response options (adaptation and mitigation). Summaries for policymakers of three reports of IPCC working groups and of the Synthesis Report have now been approved by IPCC plenaries. This present paper reports on the most essential findings in AR5. It briefly informs on the contents of reports of all IPCC working groups. It discusses the physical science findings, therein observed changes (ubiquitous warming, shrinking cryosphere, sea level rise, changes in precipitation and extremes, and biogeochemical cycles). It deals with the drivers of climate change, progress in climate system understanding (evaluation of climate models, quantification of climate system responses), and projections for the future. It reviews impacts, adaptation and vulnerability, including observed changes, key risks, key reasons for concern, sectors and systems, and managing risks and building resilience. Finally, mitigation of climate change is discussed, including greenhouse gas emissions in the past, present and future, and mitigation in sectors. It is hoped that the present article will encourage the readership of this journal to dive into the AR5 report that provides a wealth of useful information.

Climate of the past 2000 years in IPCC AR5 (Invited)

NASA Astrophysics Data System (ADS)

Masson-Delmotte, V.

2013-12-01

Different aspects of the climate of the past 2000 years are covered in several chapters of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, including information from paleoclimate archives, changes in the carbon and biogeochemical cycles, changes in sea level, climate model evaluation and detection and attribution. This presentation will summarize the main findings regarding pre-industrial changes in radiative forcings, reconstructed and simulated temperature variations at the hemispheric and regional scales, as well as global sea level for the past 2000 years, in the perspective of the current and earlier interglacial periods.

Towards the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC)

NASA Astrophysics Data System (ADS)

Fuglestvedt, J. S.; Masson-Delmotte, V.; Zhai, P.; Pirani, A.

2016-12-01

The IPCC, set up in 1988 by WMO and UNEP, is the international body for assessing the science related to climate change. The reports of the IPCC include Assessments, Synthesis and Special Reports (and their Summaries for Policymakers), as well as Methodological Reports, providing policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation. These assessments are policy-relevant, but not policy-prescriptive, and based on the assessment of the published literature. The assessments of the IPCC follow precise procedures to ensure that they provide a rigorous and balanced scientific information. Particularly critical is the volunteer involvment of tens of scientists involved in the scoping of each report, as well as the work of hundreds of Coordinating Lead Authors and Lead Authors of reports, with the complementary expertise of hundreds of sollicited Contributing Authors. The review process plays a key role in the open and transparent process underlying the IPCC reports. It is organized in multiple rounds and mobilizes thousands of other experts, a process monitored by Review Editors. The author teams develop rigorous methodologies to report the degree of confidence associated with each finding and report information with uncertainty. As a result, successive IPCC reports provide regular steps to determine matured climate science, through robust findings, but also emerging research pathways, and facilitate science maturation through analyses of multiple perspectives provided by the scientific literature in a comprehensive approach. While the IPCC does not conduct its own scientific research, the timeline of the IPCC reports acts as a stimulation for the research community, especially for internationally coordinated research programmes associated with global climate projections. These aspects will be developed in this presentation, with a focus on Working Group I (the physical science basis), and the 6th Assessment Report (AR6). For more information, see : www.ipcc.ch For new special reports planned in 2018-2019 : http://www.ipcc.ch/activities/activities.shtml For the strategic planning schedule for the AR6 : http://www.ipcc.ch/activities/pdf/ar6_WSPSchedule_07072016.pdf

Landfalling Atmospheric Rivers in California—Historical and Future Impacts

NASA Astrophysics Data System (ADS)

Dettinger, M. D.; Ralph, F. M.

2014-12-01

During the past decade, a wide range of insights about the character and causes of extreme orographic precipitation in California has emerged, based on our growing understanding of the presence, mechanisms and impacts of "atmospheric rivers" (ARs) in the extratropical atmosphere. When an AR reaches and encounters the Coastal Ranges and Sierra Nevada of California, the resulting orographically driven storms are key players in many important weather, hydrologic and ecological processes in the State, including floods and floodplain inundations, droughts, groundwater recharge, and surface-water resources (see table). The intensities, storm totals, geographical distributions and impacts of AR storms in California are determined by many factors, including among the most straightforward: The numbers of ARs making landfall each year The amounts of vapor being transported by the ARs The direction of vapor transport by the AR relative to perpendiculars to the mountain ranges (for maximum uplift) The duration of AR passage overhead of a given location The temperature of an AR as a determinant of snowline altitudes The stability of the atmosphere within which the AR is embedded The closeness of the air in the AR to saturation (how much uplift is needed to drive intense precipitation) ARs are present in weather forecast models as well as in the long-range climate models used to project future climate changes in response to increasing greenhouse-gas concentrations in the atmosphere. Research into the future of ARs over California was first reported in the literature in 2011 (based on IPCC AR4 climate models) and is being extended now (to IPCC AR5 models) to assess projected changes in the full range of factors listed above with the aim of predicting how climate change will affect these important storms and their impacts in coming decades.

Dominant frames in legacy and social media coverage of the IPCC Fifth Assessment Report

NASA Astrophysics Data System (ADS)

O'Neill, Saffron; Williams, Hywel T. P.; Kurz, Tim; Wiersma, Bouke; Boykoff, Maxwell

2015-04-01

The media are powerful agents that translate information across the science-policy interface, framing it for audiences. Yet frames are never neutral: they define an issue, identify causes, make moral judgements and shape proposed solutions. Here, we show how the IPCC Fifth Assessment Report (AR5) was framed in UK and US broadcast and print coverage, and on Twitter. Coverage of IPCC Working Group I (WGI) was contested and politicized, employing the `Settled Science, Uncertain Science, Political or Ideological Struggle and Role of Science’ frames. WGII coverage commonly used Disaster or Security. More diverse frames were employed for WGII and WGIII, including Economics and Morality and Ethics. Framing also varied by media institution: for example, the BBC used Uncertain Science, whereas Channel 4 did not. Coverage varied by working group, with WGIII gaining far less coverage than WGI or WGII. We suggest that media coverage and framing of AR5 was influenced by its sequential three-part structure and by the availability of accessible narratives and visuals. We recommend that these communication lessons be applied to future climate science reports.

A Defence of the AR4’s Bayesian Approach to Quantifying Uncertainty

NASA Astrophysics Data System (ADS)

Vezer, M. A.

2009-12-01

The field of climate change research is a kimberlite pipe filled with philosophic diamonds waiting to be mined and analyzed by philosophers. Within the scientific literature on climate change, there is much philosophical dialogue regarding the methods and implications of climate studies. To this date, however, discourse regarding the philosophy of climate science has been confined predominately to scientific - rather than philosophical - investigations. In this paper, I hope to bring one such issue to the surface for explicit philosophical analysis: The purpose of this paper is to address a philosophical debate pertaining to the expressions of uncertainty in the International Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), which, as will be noted, has received significant attention in scientific journals and books, as well as sporadic glances from the popular press. My thesis is that the AR4’s Bayesian method of uncertainty analysis and uncertainty expression is justifiable on pragmatic grounds: it overcomes problems associated with vagueness, thereby facilitating communication between scientists and policy makers such that the latter can formulate decision analyses in response to the views of the former. Further, I argue that the most pronounced criticisms against the AR4’s Bayesian approach, which are outlined below, are misguided. §1 Introduction Central to AR4 is a list of terms related to uncertainty that in colloquial conversations would be considered vague. The IPCC attempts to reduce the vagueness of its expressions of uncertainty by calibrating uncertainty terms with numerical probability values derived from a subjective Bayesian methodology. This style of analysis and expression has stimulated some controversy, as critics reject as inappropriate and even misleading the association of uncertainty terms with Bayesian probabilities. [...] The format of the paper is as follows. The investigation begins (§2) with an explanation of background considerations relevant to the IPCC and its use of uncertainty expressions. It then (§3) outlines some general philosophical worries regarding vague expressions and (§4) relates those worries to the AR4 and its method of dealing with them, which is a subjective Bayesian probability analysis. The next phase of the paper (§5) examines the notions of ‘objective’ and ‘subjective’ probability interpretations and compares the IPCC’s subjective Bayesian strategy with a frequentist approach. It then (§6) addresses objections to that methodology, and concludes (§7) that those objections are wrongheaded.

Evaluation of Drought Occurrence and Climate Change in the Pearl River Basin in South China

NASA Astrophysics Data System (ADS)

DU, Y.; Chen, J.; Wang, K.; Shi, H.

2015-12-01

This study uses the Variable Infiltration Capacity (VIC) Model to simulate the hydrological processes over the Pearl River basin in South China. The observed streamflow data in the Pearl River Basin for the period 1951-2000 are used to evaluate the model simulation results. Further, in this study, the 55 datasets of climate projection from 18 General Circulation Models (GCMs) for the IPCC AR4 (SRES A2/A1B/B1) and AR5 (RCP 2.6/4.5/6.0/8.5) are used to drive the VIC model at 0.5°× 0.5°spatial resolution and daily temporal resolution. Then, the monthly Standard Precipitation Index (SPI) and standardized runoff index (SRI) are generated to detect the drought occurrence. This study validates the GCMs projection through comparing the observed precipitation for the period of 2000-2013. Then, spatial variation of the frequency change of moderate drought, severe drought and extreme drought are analyzed for the 21st century. The study reveals that the frequencies of severe drought and extreme drought occurrences over the Pearl River Basin increase along with time. Specifically, for the scenario of AR5 RCP 8.5, the east and west parts of the Pearl River Basin most likely suffer from severe drought and extreme drought with an increased frequency throughout the 21st century.

Progress toward Consensus Estimates of Regional Glacier Mass Balances for IPCC AR5

NASA Astrophysics Data System (ADS)

Arendt, A. A.; Gardner, A. S.; Cogley, J. G.

2011-12-01

Glaciers are potentially large contributors to rising sea level. Since the last IPCC report in 2007 (AR4), there has been a widespread increase in the use of geodetic observations from satellite and airborne platforms to complement field observations of glacier mass balance, as well as significant improvements in the global glacier inventory. Here we summarize our ongoing efforts to integrate data from multiple sources to arrive at a consensus estimate for each region, and to quantify uncertainties in those estimates. We will use examples from Alaska to illustrate methods for combining Gravity Recovery and Climate Experiment (GRACE), elevation differencing and field observations into a single time series with related uncertainty estimates. We will pay particular attention to reconciling discrepancies between GRACE estimates from multiple processing centers. We will also investigate the extent to which improvements in the glacier inventory affect the accuracy of our regional mass balances.

An interactive web application for visualizing climate data

USGS Publications Warehouse

Alder, J.; Hostetler, S.; Williams, D.

2013-01-01

Massive volumes of data are being created as modeling centers from around the world finalize their submission of climate simulations for the Coupled Model Intercomparison Project, phase 5 (CMIP5), in preparation for the forthcoming Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Scientists, resource managers, and other potential users of climate data are faced with the daunting task of analyzing, distilling, and summarizing this unprecedented wealth of climate information.

An Interactive Web Application for Visualizing Climate Data

NASA Astrophysics Data System (ADS)

Alder, J.; Hostetler, S.; Williams, D.

2013-05-01

Massive volumes of data are being created as modeling centers from around the world finalize their submission of climate simulations for the Coupled Model Intercomparison Project, phase 5 (CMIP5), in preparation for the forthcoming Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Scientists, resource managers, and other potential users of climate data are faced with the daunting task of analyzing, distilling, and summarizing this unprecedented wealth of climate information.

Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) "reasons for concern".

PubMed

Smith, Joel B; Schneider, Stephen H; Oppenheimer, Michael; Yohe, Gary W; Hare, William; Mastrandrea, Michael D; Patwardhan, Anand; Burton, Ian; Corfee-Morlot, Jan; Magadza, Chris H D; Füssel, Hans-Martin; Pittock, A Barrie; Rahman, Atiq; Suarez, Avelino; van Ypersele, Jean-Pascal

2009-03-17

Article 2 of the United Nations Framework Convention on Climate Change [United Nations (1992) http://unfccc.int/resource/docs/convkp/conveng.pdf. Accessed February 9, 2009] commits signatory nations to stabilizing greenhouse gas concentrations in the atmosphere at a level that "would prevent dangerous anthropogenic interference (DAI) with the climate system." In an effort to provide some insight into impacts of climate change that might be considered DAI, authors of the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) identified 5 "reasons for concern" (RFCs). Relationships between various impacts reflected in each RFC and increases in global mean temperature (GMT) were portrayed in what has come to be called the "burning embers diagram." In presenting the "embers" in the TAR, IPCC authors did not assess whether any single RFC was more important than any other; nor did they conclude what level of impacts or what atmospheric concentrations of greenhouse gases would constitute DAI, a value judgment that would be policy prescriptive. Here, we describe revisions of the sensitivities of the RFCs to increases in GMT and a more thorough understanding of the concept of vulnerability that has evolved over the past 8 years. This is based on our expert judgment about new findings in the growing literature since the publication of the TAR in 2001, including literature that was assessed in the IPCC Fourth Assessment Report (AR4), as well as additional research published since AR4. Compared with results reported in the TAR, smaller increases in GMT are now estimated to lead to significant or substantial consequences in the framework of the 5 "reasons for concern."

Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) “reasons for concern”

PubMed Central

Smith, Joel B.; Schneider, Stephen H.; Oppenheimer, Michael; Yohe, Gary W.; Hare, William; Mastrandrea, Michael D.; Patwardhan, Anand; Burton, Ian; Corfee-Morlot, Jan; Magadza, Chris H. D.; Füssel, Hans-Martin; Pittock, A. Barrie; Rahman, Atiq; Suarez, Avelino; van Ypersele, Jean-Pascal

2009-01-01

Article 2 of the United Nations Framework Convention on Climate Change [United Nations (1992) http://unfccc.int/resource/docs/convkp/conveng.pdf. Accessed February 9, 2009] commits signatory nations to stabilizing greenhouse gas concentrations in the atmosphere at a level that “would prevent dangerous anthropogenic interference (DAI) with the climate system.” In an effort to provide some insight into impacts of climate change that might be considered DAI, authors of the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) identified 5 “reasons for concern” (RFCs). Relationships between various impacts reflected in each RFC and increases in global mean temperature (GMT) were portrayed in what has come to be called the “burning embers diagram.” In presenting the “embers” in the TAR, IPCC authors did not assess whether any single RFC was more important than any other; nor did they conclude what level of impacts or what atmospheric concentrations of greenhouse gases would constitute DAI, a value judgment that would be policy prescriptive. Here, we describe revisions of the sensitivities of the RFCs to increases in GMT and a more thorough understanding of the concept of vulnerability that has evolved over the past 8 years. This is based on our expert judgment about new findings in the growing literature since the publication of the TAR in 2001, including literature that was assessed in the IPCC Fourth Assessment Report (AR4), as well as additional research published since AR4. Compared with results reported in the TAR, smaller increases in GMT are now estimated to lead to significant or substantial consequences in the framework of the 5 “reasons for concern.” PMID:19251662

Northern African and Indian Precipitation at the end of the 21st Century: An Integrated Application of Regional and Global Climate Models

NASA Astrophysics Data System (ADS)

Patricola, C. M.; Cook, K. H.

2008-12-01

As greenhouse warming continues there is growing concern about the future climate of both Africa, which is highlighted by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) as exceptionally vulnerable to climate change, and India. Precipitation projections from the AOGCMs of the IPCC AR4 are relatively consistent over India, but not over northern Africa. Inconsistencies can be related to the model's inability to capture climate process correctly, deficiencies in physical parameterizations, different SST projections, or horizontal atmospheric resolution that is too coarse to realistically represent the tight gradients over West Africa and complex topography of East Africa and India. Treatment of the land surface in a model may also be an issue over West Africa and India where land-surface/atmosphere interactions are very important. Here a method for simulating future climate is developed and applied using a high-resolution regional model in conjunction with output from a suite of AOGCMs, drawing on the advantages of both the regional and global modeling approaches. Integration by the regional model allows for finer horizontal resolution and regionally appropriate selection of parameterizations and land-surface model. AOGCM output is used to provide SST projections and lateral boundary conditions to constrain the regional model. The control simulation corresponds to 1981-2000, and eight future simulations representing 2081-2100 are conducted, each constrained by a different AOGCM and forced by CO2 concentrations from the SRES A2 emissions scenario. After model spin-up, May through October remain for investigation. Analysis is focused on climate change parameters important for impacts on agriculture and water resource management, and is presented in a format compatible with the IPCC reports. Precipitation projections simulated by the regional model are quite consistent, with 75% or more ensemble members agreeing on the sign of the anomaly over vast regions of Africa and India. Over West Africa, where the regional model provides the greatest improvement over the AOGCMs in consistency of ensemble members, precipitation at the end of the century is generally projected to increase during May and decrease in June and July. Wetter conditions are simulated during August though October, with the exception of drying close to the Guinean Coast in August. In late summer, high rainfall rates are simulated more frequently in the future, indicating the possibility for increases in flooding events. The regional model's projections over India are in stark contrast to the AOGCM's, producing intense and generally widespread drying in August and September. The very promising method developed here is young and further potential developments are recognized, including the addition of ocean, vegetation, and dust models. Ensembles which employ other regional models, sets of parameterizations, and emissions scenarios should also be explored.

Introducing Subgrid-scale convective cloud and aerosol interactions to the WRF-CMAQ integrated modeling system

EPA Science Inventory

Many regional and global climate models include aerosol indirect effects (AIE) on grid-scale/resolved clouds. However, the interaction between aerosols and convective clouds remains highly uncertain, as noted in the IPCC AR4 report. The objective of this work is to help fill in ...

Evaluation of surface water budget and assessment the global water cycle for the IPCC AR4 A1B scenario simulations

NASA Astrophysics Data System (ADS)

Baek, H.; Park, E.; Kwon, W.

2009-12-01

Water balance calculations are becoming increasingly important for earth-system studies, because humans require water for their survival. Especially, the relationship between climate change and freshwater resources is of primary concern to human society and also has implications for all living species. The goal of this study is to assess the closure and annual variations of the water cycles based on the multi-model ensemble approach. In this study, the projection results of the previous works focusing on global and six sub-regions are updated using sixteen atmosphere-ocean general circulation model (AOGCM) simulations based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario. Before projecting future climate, model performances are evaluated on the simulation of the present-day climate. From the result, we construct and use mainly multi-model ensembles (MMEs), which is referred to as MME9, defined from nine selected AOGCMs of higher performance. Analyzed variables include annual and seasonal precipitation, evaporation, and runoff. The overall projection results from MME9 show that most regions will experience warmer and wetter climate at the end of 21st century. The evaporation shows a very similar trend to precipitation, but not in the runoff projection. The internal and inter-model variabilities are larger in the runoff than both precipitation and evaporation. Moreover, the runoff is notably reduced in Europe at the end of 21st century.

Coastal sea level projections with improved accounting for vertical land motion

PubMed Central

Han, Guoqi; Ma, Zhimin; Chen, Nan; Yang, Jingsong; Chen, Nancy

2015-01-01

Regional and coastal mean sea level projections in the Intergovernmental Panel for Climate Change (IPCC) Fifth Assessment Report (AR5) account only for vertical land motion (VLM) associated with glacial isostatic adjustment (GIA), which may significantly under- or over-estimate sea level rise. Here we adjust AR5-like regional projections with the VLM from Global Positioning Satellite (GPS) measurements and/or from a combination of altimetry and tide-gauge data, which include both GIA and non-GIA VLM. Our results at selected tide-gauge locations on the North American and East Asian coasts show drastically different projections with and without non-GIA VLM being accounted for. The present study points to the importance of correcting IPCC AR5 coastal projections for the non-GIA VLM in making adaptation decisions. PMID:26526287

Coastal sea level projections with improved accounting for vertical land motion.

PubMed

Han, Guoqi; Ma, Zhimin; Chen, Nan; Yang, Jingsong; Chen, Nancy

2015-11-03

Regional and coastal mean sea level projections in the Intergovernmental Panel for Climate Change (IPCC) Fifth Assessment Report (AR5) account only for vertical land motion (VLM) associated with glacial isostatic adjustment (GIA), which may significantly under- or over-estimate sea level rise. Here we adjust AR5-like regional projections with the VLM from Global Positioning Satellite (GPS) measurements and/or from a combination of altimetry and tide-gauge data, which include both GIA and non-GIA VLM. Our results at selected tide-gauge locations on the North American and East Asian coasts show drastically different projections with and without non-GIA VLM being accounted for. The present study points to the importance of correcting IPCC AR5 coastal projections for the non-GIA VLM in making adaptation decisions.

Summary for Policymakers IPCC Fourth Assessment Report, WorkingGroup III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, Terry; Bashmakov, Igor; Bernstein, Lenny

2007-04-30

A. Introduction 1. The Working Group III contribution to theIPCC Fourth Assessment Report (AR4) focuses on new literature on thescientific, technological, environmental, economic and social aspects ofmitigation of climate change, published since the IPCC Third AssessmentReport (TAR) and the Special Reports on COB2B Capture and Storage (SRCCS)and on Safeguarding the Ozone Layer and the Global Climate System (SROC).The following summary is organised into six sections after thisintroduction: - Greenhouse gas (GHG) emission trends, - Mitigation in theshort and medium term, across different economic sectors (until 2030), -Mitigation in the long-term (beyond 2030), - Policies, measures andinstruments to mitigate climate change,more » - Sustainable development andclimate change mitigation, - Gaps in knowledge. References to thecorresponding chapter sections are indicated at each paragraph in squarebrackets. An explanation of terms, acronyms and chemical symbols used inthis SPM can be found in the glossary to the main report.« less

Advanced Large Scale Cross Domain Temporal Topic Modeling Algorithms to Infer the Influence of Recent Research on IPCC Assessment Reports

NASA Astrophysics Data System (ADS)

Sleeman, J.; Halem, M.; Finin, T.; Cane, M. A.

2016-12-01

Approximately every five years dating back to 1989, thousands of climate scientists, research centers and government labs volunteer to prepare comprehensive Assessment Reports for the Intergovernmental Panel on Climate Change. These are highly curated reports distributed to 200 nation policy makers. There have been five IPCC Assessment Reports to date, the latest leading to a Paris Agreement in Dec. 2016 signed thus far by 172 nations to limit the amount of global Greenhouse gases emitted to producing no more than a 20 C warming of the atmosphere. These reports are a living evolving big data collection tracing 30 years of climate science research, observations, and model scenario intercomparisons. They contain more than 200,000 citations over a 30 year period that trace the evolution of the physical basis of climate science, the observed and predicted impact, risk and adaptation to increased greenhouse gases and mitigation approaches, pathways, policies for climate change. Document-topic and topic-term probability distributions are built from the vocabularies of the respective assessment report chapters and citations. Using Microsoft Bing, we retrieve 150,000 citations referenced across chapters and convert those citations to text. Using a word n-gram model based on a heterogeneous set of climate change terminology, lemmatization, noise filtering and stopword elimination, we calculate word frequencies for chapters and citations. Temporal document sets are built based on the assessment period. In addition to topic modeling, we employ cross domain correlation measures. Using the Jensen-Shannon divergence and Pearson correlation we build correlation matrices for chapter and citations topics. The shared vocabulary acts as the bridge between domains resulting in chapter-citation point pairs in space. Pairs are established based on a document-topic probability distribution. Each chapter and citation is associated with a vector of topics and based on the n most probable topics, we establish which chapter-citation pairs are most similar. We will perform posterior inferences based on Hastings -Metropolis simulated annealing MCMC algorithm to infer, from the evolution of topics starting from AR1 to AR4, assertions of topics for AR5 and potentially AR6.

Forecasting Future Sea Ice Conditions: A Lagrangian Approach

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Forecasting Future Sea Ice Conditions: A Lagrangian ...GCMs participating in IPCC AR5 agree with observed source region patterns from the satellite- derived dataset. 4- Compare Lagrangian ice... Lagrangian sea-ice back trajectories to estimate thermodynamic and dynamic (advection) ice loss. APPROACH We use a Lagrangian trajectory model to

Causes and implications of the growing divergence between climate model simulations and observations

NASA Astrophysics Data System (ADS)

Curry, Judith

2014-03-01

For the past 15+ years, there has been no increase in global average surface temperature, which has been referred to as a 'hiatus' in global warming. By contrast, estimates of expected warming in the first several decades of 21st century made by the IPCC AR4 were 0.2C/decade. This talk summarizes the recent CMIP5 climate model simulation results and comparisons with observational data. The most recent climate model simulations used in the AR5 indicate that the warming stagnation since 1998 is no longer consistent with model projections even at the 2% confidence level. Potential causes for the model-observation discrepancies are discussed. A particular focus of the talk is the role of multi-decadal natural internal variability on the climate variability of the 20th and early 21st centuries. The ``stadium wave'' climate signal is described, which propagates across the Northern Hemisphere through a network of ocean, ice, and atmospheric circulation regimes that self-organize into a collective tempo. The stadium wave hypothesis provides a plausible explanation for the hiatus in warming and helps explain why climate models did not predict this hiatus. Further, the new hypothesis suggests how long the hiatus might last. Implications of the hiatus are discussed in context of climate model sensitivity to CO2 forcing and attribution of the warming that was observed in the last quarter of the 20th century.

AIRS Obs4MIPs V2 data set

NASA Astrophysics Data System (ADS)

Tian, B.

2017-12-01

The Coupled Model Intercomparison Project (CMIP) has become a central element of national and international assessments of climate change. The CMIP Phase 6 (CMIP6) model experiments will be the foundation for the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), scheduled for publication around 2021. To increase the fidelity of the IPCC AR6, the CMIP6 model experiments need rigorous evaluation. The "Observations for Model Intercomparison Projects" (Obs4MIPs) collects, organizes and publishes various well-established satellite data sets for CMIP model evaluation. The Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU), the NASA's temperature and humidity sounding system on the Aqua satellite, has provided over a decade-long high-quality tropospheric temperature and moisture sounding data. Under the current support of the NASA Data for Operation and Assessment (NDOA) program, we are generating and publishing the AIRS Obs4MIPs V2 data set including the monthly mean tropospheric air temperature, specific humidity, and relative humidity profiles from September 2002 to September 2016. This will provide the latest AIRS data in Obs4MIPs and assist the climate modeling community to better use the AIRS data for CMIP (including CMIP3, CMIP5, and CMIP6) model evaluation. In this presentation, we will discuss the AIRS Obs4MIPs V2 data set and their possible use for CMIP6 climate model evaluation.

Downscaled and debiased climate simulations for North America from 21,000 years ago to 2100AD

PubMed Central

Lorenz, David J.; Nieto-Lugilde, Diego; Blois, Jessica L.; Fitzpatrick, Matthew C.; Williams, John W.

2016-01-01

Increasingly, ecological modellers are integrating paleodata with future projections to understand climate-driven biodiversity dynamics from the past through the current century. Climate simulations from earth system models are necessary to this effort, but must be debiased and downscaled before they can be used by ecological models. Downscaling methods and observational baselines vary among researchers, which produces confounding biases among downscaled climate simulations. We present unified datasets of debiased and downscaled climate simulations for North America from 21 ka BP to 2100AD, at 0.5° spatial resolution. Temporal resolution is decadal averages of monthly data until 1950AD, average climates for 1950–2005 AD, and monthly data from 2010 to 2100AD, with decadal averages also provided. This downscaling includes two transient paleoclimatic simulations and 12 climate models for the IPCC AR5 (CMIP5) historical (1850–2005), RCP4.5, and RCP8.5 21st-century scenarios. Climate variables include primary variables and derived bioclimatic variables. These datasets provide a common set of climate simulations suitable for seamlessly modelling the effects of past and future climate change on species distributions and diversity. PMID:27377537

Downscaled and debiased climate simulations for North America from 21,000 years ago to 2100AD.

PubMed

Lorenz, David J; Nieto-Lugilde, Diego; Blois, Jessica L; Fitzpatrick, Matthew C; Williams, John W

2016-07-05

Increasingly, ecological modellers are integrating paleodata with future projections to understand climate-driven biodiversity dynamics from the past through the current century. Climate simulations from earth system models are necessary to this effort, but must be debiased and downscaled before they can be used by ecological models. Downscaling methods and observational baselines vary among researchers, which produces confounding biases among downscaled climate simulations. We present unified datasets of debiased and downscaled climate simulations for North America from 21 ka BP to 2100AD, at 0.5° spatial resolution. Temporal resolution is decadal averages of monthly data until 1950AD, average climates for 1950-2005 AD, and monthly data from 2010 to 2100AD, with decadal averages also provided. This downscaling includes two transient paleoclimatic simulations and 12 climate models for the IPCC AR5 (CMIP5) historical (1850-2005), RCP4.5, and RCP8.5 21st-century scenarios. Climate variables include primary variables and derived bioclimatic variables. These datasets provide a common set of climate simulations suitable for seamlessly modelling the effects of past and future climate change on species distributions and diversity.

An international land-biosphere model benchmarking activity for the IPCC Fifth Assessment Report (AR5)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, Forrest M; Randerson, James T; Thornton, Peter E

2009-12-01

The need to capture important climate feedbacks in general circulation models (GCMs) has resulted in efforts to include atmospheric chemistry and land and ocean biogeochemistry into the next generation of production climate models, called Earth System Models (ESMs). While many terrestrial and ocean carbon models have been coupled to GCMs, recent work has shown that such models can yield a wide range of results (Friedlingstein et al., 2006). This work suggests that a more rigorous set of global offline and partially coupled experiments, along with detailed analyses of processes and comparisons with measurements, are needed. The Carbon-Land Model Intercomparison Projectmore » (C-LAMP) was designed to meet this need by providing a simulation protocol and model performance metrics based upon comparisons against best-available satellite- and ground-based measurements (Hoffman et al., 2007). Recently, a similar effort in Europe, called the International Land Model Benchmark (ILAMB) Project, was begun to assess the performance of European land surface models. These two projects will now serve as prototypes for a proposed international land-biosphere model benchmarking activity for those models participating in the IPCC Fifth Assessment Report (AR5). Initially used for model validation for terrestrial biogeochemistry models in the NCAR Community Land Model (CLM), C-LAMP incorporates a simulation protocol for both offline and partially coupled simulations using a prescribed historical trajectory of atmospheric CO2 concentrations. Models are confronted with data through comparisons against AmeriFlux site measurements, MODIS satellite observations, NOAA Globalview flask records, TRANSCOM inversions, and Free Air CO2 Enrichment (FACE) site measurements. Both sets of experiments have been performed using two different terrestrial biogeochemistry modules coupled to the CLM version 3 in the Community Climate System Model version 3 (CCSM3): the CASA model of Fung, et al., and the carbon-nitrogen (CN) model of Thornton. Comparisons of the CLM3 offline results against observational datasets have been performed and are described in Randerson et al. (2009). CLM version 4 has been evaluated using C-LAMP, showing improvement in many of the metrics. Efforts are now underway to initiate a Nitrogen-Land Model Intercomparison Project (N-LAMP) to better constrain the effects of the nitrogen cycle in biosphere models. Presented will be new results from C-LAMP for CLM4, initial N-LAMP developments, and the proposed land-biosphere model benchmarking activity.« less

Assessing Climate Change Risks Using a Multi-Model Approach

NASA Astrophysics Data System (ADS)

Knorr, W.; Scholze, M.; Prentice, C.

2007-12-01

We quantify the risks of climate-induced changes in key ecosystem processes during the 21st century by forcing a dynamic global vegetation model with multiple scenarios from the IPCC AR4 data archive using 16 climate models and mapping the proportions of model runs showing exceedance of natural variability in wildfire frequency and freshwater supply or shifts in vegetation cover. Our analysis does not assign probabilities to scenarios. Instead, we consider the distribution of outcomes within three sets of model runs grouped according to the amount of global warming they simulate: < 2 degree C (including committed climate change simulations), 2-3 degree C, and >3 degree C. Here, we are contrasting two different methods for calculating the risks: first we use an equal weighting approach giving every model within one of the three sets the same weight, and second, we weight the models according to their ability to model ENSO. The differences are underpinning the need for the development of more robust performance metrics for global climate models.

The Early Eocene equable climate problem: can perturbations of climate model parameters identify possible solutions?

PubMed

Sagoo, Navjit; Valdes, Paul; Flecker, Rachel; Gregoire, Lauren J

2013-10-28

Geological data for the Early Eocene (56-47.8 Ma) indicate extensive global warming, with very warm temperatures at both poles. However, despite numerous attempts to simulate this warmth, there are remarkable data-model differences in the prediction of these polar surface temperatures, resulting in the so-called 'equable climate problem'. In this paper, for the first time an ensemble with a perturbed climate-sensitive model parameters approach has been applied to modelling the Early Eocene climate. We performed more than 100 simulations with perturbed physics parameters, and identified two simulations that have an optimal fit with the proxy data. We have simulated the warmth of the Early Eocene at 560 ppmv CO2, which is a much lower CO2 level than many other models. We investigate the changes in atmospheric circulation, cloud properties and ocean circulation that are common to these simulations and how they differ from the remaining simulations in order to understand what mechanisms contribute to the polar warming. The parameter set from one of the optimal Early Eocene simulations also produces a favourable fit for the last glacial maximum boundary climate and outperforms the control parameter set for the present day. Although this does not 'prove' that this model is correct, it is very encouraging that there is a parameter set that creates a climate model able to simulate well very different palaeoclimates and the present-day climate. Interestingly, to achieve the great warmth of the Early Eocene this version of the model does not have a strong future climate change Charney climate sensitivity. It produces a Charney climate sensitivity of 2.7(°)C, whereas the mean value of the 18 models in the IPCC Fourth Assessment Report (AR4) is 3.26(°)C±0.69(°)C. Thus, this value is within the range and below the mean of the models included in the AR4.

Coupled model simulations of climate changes in the 20th century and beyond

NASA Astrophysics Data System (ADS)

Yu, Yongqiang; Zhi, Hai; Wang, Bin; Wan, Hui; Li, Chao; Liu, Hailong; Li, Wei; Zheng, Weipeng; Zhou, Tianjun

2008-07-01

Several scenario experiments of the IPCC 4th Assessment Report (AR4) are performed by version g1.0 of a Flexible coupled Ocean-Atmosphere-Land System Model (FGOALS) developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS), including the “Climate of the 20th century experiment”, “CO2 1% increase per year to doubling experiment” and two separate IPCC greenhouse gases emission scenarios A1B and B1 experiments. To distinguish between the different impacts of natural variations and human activities on the climate change, three-member ensemble runs are performed for each scenario experiment. The coupled model simulations show: (1) from 1900 to 2000, the global mean temperature increases about 0.5°C and the major increase occurs during the later half of the 20th century, which is in consistent with the observations that highlights the coupled model’s ability to reproduce the climate changes since the industrial revolution; (2) the global mean surface air temperature increases about 1.6°C in the CO2 doubling experiment and 1.5°C and 2.4°C in the A1B and B1 scenarios, respectively. The global warming is indicated by not only the changes of the surface temperature and precipitation but also the temperature increase in the deep ocean. The thermal expansion of the sea water would induce the rise of the global mean sea level. Both the control run and the 20th century climate change run are carried out again with version g1.1 of FGOALS, in which the cold biases in the high latitudes were removed. They are then compared with those from version g1.0 of FGOALS in order to distinguish the effect of the model biases on the simulation of global warming.

South Asian Summer Monsoon and Its Relationship with ENSO in the IPCC AR4 Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annamalai, H; Hamilton, K; Sperber, K R

In this paper we use the extensive integrations produced for the IPCC Fourth Assessment Report (AR4) to examine the relationship between ENSO and the monsoon at interannual and decadal timescales. We begin with an analysis of the monsoon simulation in the 20th century integrations. Six of the 18 models were found to have a reasonably realistic representation of monsoon precipitation climatology. For each of these six models SST and anomalous precipitation evolution along the equatorial Pacific during El Nino events display considerable differences when compared to observations. Out of these six models only four (GFDL{_}CM{_}2.0, GFDL{_}CM{_}2.1, MRI, and MPI{_}ECHAM5) exhibitmore » a robust ENSO-monsoon contemporaneous teleconnection, including the known inverse relationship between ENSO and rainfall variations over India. Lagged correlations between the all-India rainfall (AIR) index and Nino3.4 SST reveal that three models represent the timing of the teleconnection, including the spring predictability barrier which is manifested as the transition from positive to negative correlations prior to the monsoon onset. Furthermore, only one of these three models (GFDL{_}CM{_}2.1) captures the observed phase lag with the strongest anticorrelation of SST peaking 2-3 months after the summer monsoon, which is partially attributable to the intensity of simulated El Nino itself. We find that the models that best capture the ENSO-monsoon teleconnection are those that correctly simulate the timing and location of SST and diabatic heating anomalies in the equatorial Pacific, and the associated changes to the equatorial Walker Circulation during El Nino events. The strength of the AIR-Nino3.4 SST correlation in the model runs waxes and wanes to some degree on decadal timescales. The overall magnitude and timescale for this decadal modulation in most of the models is similar to that seen in observations. However, there is little consistency in the phase among the realizations, suggesting a lack of predictability of the decadal modulation of the monsoon-ENSO relationship. The analysis was repeated for each of the four models using results from integrations in which the atmospheric CO{sub 2} concentration was raised to twice pre-industrial values. From these ''best'' models in the double CO{sub 2} simulations there are increases in both the mean monsoon rainfall over the Indian sub-continent (by 5-25%) and in its interannual variability (5-10%). We find for each model that the ENSO-monsoon correlation in the global warming runs is very similar to that in the 20th century runs, suggesting that the ENSO-monsoon connection will not weaken as global climate warms. This result, though plausible, needs to be taken with some caution because of the diversity in the simulation of ENSO variability in the coupled models we have analyzed. The implication of the present results for monsoon prediction are discussed.« less

Projected Sea Level Rise and Changes in Extreme Storm Surge and Wave Events During the 21st Century in the Region of Singapore

NASA Astrophysics Data System (ADS)

Palmer, M. D.; Cannaby, H.; Howard, T.; Bricheno, L.

2016-02-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled ( 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980-2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m(0.74 m) under the RCP 4.5(8.5) scenarios respectively. Trends in surge and significant wave height 2-year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

NASA Astrophysics Data System (ADS)

Cannaby, H.; Palmer, M. D.; Howard, T.; Bricheno, L.; Calvert, D.; Krijnen, J.; Wood, R.; Tinker, J.; Bunney, C.; Harle, J.; Saulter, A.; O'Neill, C.; Bellingham, C.; Lowe, J.

2015-12-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using ~ 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled (~ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980-2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the RCP 4.5 (8.5) scenarios respectively. Trends in surge and significant wave height 2 year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of ~ 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

A carbon cycle science update since IPCC AR-4.

PubMed

Dolman, A J; van der Werf, G R; van der Molen, M K; Ganssen, G; Erisman, J-W; Strengers, B

2010-01-01

We review important advances in our understanding of the global carbon cycle since the publication of the IPCC AR4. We conclude that: the anthropogenic emissions of CO2 due to fossil fuel burning have increased up through 2008 at a rate near to the high end of the IPCC emission scenarios; there are contradictory analyses whether an increase in atmospheric fraction, that might indicate a declining sink strength of ocean and/or land, exists; methane emissions are increasing, possibly through enhanced natural emission from northern wetland, methane emissions from dry plants are negligible; old-growth forest take up more carbon than expected from ecological equilibrium reasoning; tropical forest also take up more carbon than previously thought, however, for the global budget to balance, this would imply a smaller uptake in the northern forest; the exchange fluxes between the atmosphere and ocean are increasingly better understood and bottom up and observation-based top down estimates are getting closer to each other; the North Atlantic and Southern ocean take up less CO2, but it is unclear whether this is part of the 'natural' decadal scale variability; large-scale fires and droughts, for instance in Amazonia, but also at Northern latitudes, have lead to significant decreases in carbon uptake on annual timescales; the extra uptake of CO2 stimulated by increased N-deposition is, from a greenhouse gas forcing perspective, counterbalanced by the related additional N2O emissions; the amount of carbon stored in permafrost areas appears much (two times) larger than previously thought; preservation of existing marine ecosystems could require a CO2 stabilization as low as 450 ppm; Dynamic Vegetation Models show a wide divergence for future carbon trajectories, uncertainty in the process description, lack of understanding of the CO2 fertilization effect and nitrogen-carbon interaction are major uncertainties.

The use of Meteonorm weather generator for climate change studies

NASA Astrophysics Data System (ADS)

Remund, J.; Müller, S. C.; Schilter, C.; Rihm, B.

2010-09-01

The global climatological database Meteonorm (www.meteonorm.com) is widely used as meteorological input for simulation of solar applications and buildings. It's a combination of a climate database, a spatial interpolation tool and a stochastic weather generator. Like this typical years with hourly or minute time resolution can be calculated for any site. The input of Meteonorm for global radiation is the Global Energy Balance Archive (GEBA, http://proto-geba.ethz.ch). All other meteorological parameters are taken from databases of WMO and NCDC (periods 1961-90 and 1996-2005). The stochastic generation of global radiation is based on a Markov chain model for daily values and an autoregressive model for hourly and minute values (Aguiar and Collares-Pereira, 1988 and 1992). The generation of temperature is based on global radiation and measured distribution of daily temperature values of approx. 5000 sites. Meteonorm generates also additional parameters like precipitation, wind speed or radiation parameters like diffuse and direct normal irradiance. Meteonorm can also be used for climate change studies. Instead of climate values, the results of IPCC AR4 results are used as input. From all 18 public models an average has been made at a resolution of 1°. The anomalies of the parameters temperature, precipitation and global radiation and the three scenarios B1, A1B and A2 have been included. With the combination of Meteonorm's current database 1961-90, the interpolation algorithms and the stochastic generation typical years can be calculated for any site, for different scenarios and for any period between 2010 and 2200. From the analysis of variations of year to year and month to month variations of temperature, precipitation and global radiation of the past ten years as well of climate model forecasts (from project prudence, http://prudence.dmi.dk) a simple autoregressive model has been formed which is used to generate realistic monthly time series of future periods. Meteonorm can therefore be used as a relatively simple method to enhance the spatial and temporal resolution instead of using complicated and time consuming downscaling methods based on regional climate models. The combination of Meteonorm, gridded historical (based on work of Luterbach et al.) and IPCC results has been used for studies of vegetation simulation between 1660 and 2600 (publication of first version based on IS92a scenario and limited time period 1950 - 2100: http://www.pbl.nl/images/H5_Part2_van%20CCE_opmaak%28def%29_tcm61-46625.pdf). It's also applicable for other adaptation studies for e.g. road surfaces or building simulation. In Meteonorm 6.1 one scenario (IS92a) and one climate model has been included (Hadley CM3). In the new Meteonorm 7 (coming spring 2011) the model averages of the three above mentioned scenarios of the IPCC AR4 will be included.

Multi-Model Simulations of Aerosol and Ozone Radiative Forcing Due to Anthropogenic Emission Changes During the Period 1990-2015

NASA Technical Reports Server (NTRS)

Myhre, Gunnar; Aas, Wenche; Ribu, Cherian; Collins, William; Faluvegi, Gregory S.; Flanner, Mark; Forster, Piers; Hodnebrog, Oivind; Klimont, Zbigniew; Lund, Marianne T.

2017-01-01

Over the past few decades, the geographical distribution of emissions of substances that alter the atmospheric energy balance has changed due to economic growth and air pollution regulations. Here, we show the resulting changes to aerosol and ozone abundances and their radiative forcing using recently updated emission data for the period 1990-2015, as simulated by seven global atmospheric composition models. The models broadly reproduce large-scale changes in surface aerosol and ozone based on observations (e.g. 1 to 3 percent per year in aerosols over the USA and Europe). The global mean radiative forcing due to ozone and aerosol changes over the 1990-2015 period increased by 0.17 plus or minus 0.08 watts per square meter, with approximately one-third due to ozone. This increase is more strongly positive than that reported in IPCC AR5 (Intergovernmental Panel on Climate Change Fifth Assessment Report). The main reasons for the increased positive radiative forcing of aerosols over this period are the substantial reduction of global mean SO2 emissions, which is stronger in the new emission inventory compared to that used in the IPCC analysis, and higher black carbon emissions.

Regional Climate Change across North America in 2030 Projected from RCP6.0

NASA Astrophysics Data System (ADS)

Otte, T.; Nolte, C. G.; Faluvegi, G.; Shindell, D. T.

2012-12-01

Projecting climate change scenarios to local scales is important for understanding and mitigating the effects of climate change on society and the environment. Many of the general circulation models (GCMs) that are participating in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) do not fully resolve regional-scale processes and therefore cannot capture local changes in temperature and precipitation extremes. We seek to project the GCM's large-scale climate change signal to the local scale using a regional climate model (RCM) by applying dynamical downscaling techniques. The RCM will be used to better understand the local changes of temperature and precipitation extremes that may result from a changing climate. In this research, downscaling techniques that we developed with historical data are now applied to GCM fields. Results from downscaling NASA/GISS ModelE2 simulations of the IPCC AR5 Representative Concentration Pathway (RCP) scenario 6.0 will be shown. The Weather Research and Forecasting (WRF) model has been used as the RCM to downscale decadal time slices for ca. 2000 and ca. 2030 over North America and illustrate potential changes in regional climate that are projected by ModelE2 and WRF under RCP6.0. The analysis focuses on regional climate fields that most strongly influence the interactions between climate change and air quality. In particular, an analysis of extreme temperature and precipitation events will be presented.

Cloud Simulations in Response to Turbulence Parameterizations in the GISS Model E GCM

NASA Technical Reports Server (NTRS)

Yao, Mao-Sung; Cheng, Ye

2013-01-01

The response of cloud simulations to turbulence parameterizations is studied systematically using the GISS general circulation model (GCM) E2 employed in the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report (AR5).Without the turbulence parameterization, the relative humidity (RH) and the low cloud cover peak unrealistically close to the surface; with the dry convection or with only the local turbulence parameterization, these two quantities improve their vertical structures, but the vertical transport of water vapor is still weak in the planetary boundary layers (PBLs); with both local and nonlocal turbulence parameterizations, the RH and low cloud cover have better vertical structures in all latitudes due to more significant vertical transport of water vapor in the PBL. The study also compares the cloud and radiation climatologies obtained from an experiment using a newer version of turbulence parameterization being developed at GISS with those obtained from the AR5 version. This newer scheme differs from the AR5 version in computing nonlocal transports, turbulent length scale, and PBL height and shows significant improvements in cloud and radiation simulations, especially over the subtropical eastern oceans and the southern oceans. The diagnosed PBL heights appear to correlate well with the low cloud distribution over oceans. This suggests that a cloud-producing scheme needs to be constructed in a framework that also takes the turbulence into consideration.

Authorship in IPCC AR5 and its implications for content: climate change and Indigenous populations in WGII.

PubMed

Ford, James D; Vanderbilt, Will; Berrang-Ford, Lea

This essay examines the extent to which we can expect Indigenous Knowledge, understanding, and voices on climate change ('Indigenous content') to be captured in WGII of the IPCC Fifth Assessment Report (AR5), based on an analysis of chapter authorship. Reviewing the publishing history of 309 chapter authors (CAs) to WGII, we document 9 (2.9%) to have published on climate change and Indigenous populations and involved as authors in 6/30 chapters. Drawing upon recent scholarship highlighting how authorship affect structure and content of assessment reports, we argue that, unaddressed, this will affect the extent to which Indigenous content is examined and assessed. While it is too late to alter the structure of AR5, there are opportunities to prioritize the recruitment of contributing authors and reviewers with expertise on Indigenous issues, raise awareness among CAs on the characteristics of impacts, adaptation, and vulnerability faced by Indigenous peoples, and highlight how Indigenous perspectives can help broaden our understanding of climate change and policy interventions.

Impacts of past and future climate change on wind energy resources in the United States

NASA Astrophysics Data System (ADS)

McCaa, J. R.; Wood, A.; Eichelberger, S.; Westrick, K.

2009-12-01

The links between climate change and trends in wind energy resources have important potential implications for the wind energy industry, and have received significant attention in recent studies. We have conducted two studies that provide insights into the potential for climate change to affect future wind power production. In one experiment, we projected changes in power capacity for a hypothetical wind farm located near Kennewick, Washington, due to greenhouse gas-induced climate change, estimated using a set of regional climate model simulations. Our results show that the annual wind farm power capacity is projected to decrease 1.3% by 2050. In a wider study focusing on wind speed instead of power, we analyzed projected changes in wind speed from 14 different climate simulations that were performed in support of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). Our results show that the predicted ensemble mean changes in annual mean wind speeds are expected to be modest. However, seasonal changes and changes predicted by individual models are large enough to affect the profitability of existing and future wind projects. The majority of the model simulations reveal that near-surface wind speed values are expected to shift poleward in response to the IPCC A2 emission scenario, particularly during the winter season. In the United States, most models agree that the mean annual wind speed values will increase in a region extending from the Great Lakes southward across the Midwest and into Texas. Decreased values, though, are predicted across most of the western United States. However, these predicted changes have a strong seasonal dependence, with wind speed increases over most of the United States during the winter and decreases over the northern United States during the summer.

A Harder Rain is Going to Fall: Challenges for Actionable Projections of Extremes

NASA Astrophysics Data System (ADS)

Collins, W.

2014-12-01

Hydrometeorological extremes are projected to increase in both severity and frequency as the Earth's surface continues to warm in response to anthropogenic emissions of greenhouse gases. These extremes will directly affect the availability and reliability of water and other critical resources. The most comprehensive suite of multi-model projections has been assembled under the Coupled Model Intercomparison Project version 5 (CMIP5) and assessed in the Fifth Assessment (AR5) of the Intergovernmental Panel on Climate Change (IPCC). In order for these projections to be actionable, the projections should exhibit consistency and fidelity down to the local length and timescales required for operational resource planning, for example the scales relevant for water allocations from a major watershed. In this presentation, we summarize the length and timescales relevant for resource planning and then use downscaled versions of the IPCC simulations over the contiguous United States to address three questions. First, over what range of scales is there quantitative agreement between the simulated historical extremes and in situ measurements? Second, does this range of scales in the historical and future simulations overlap with the scales relevant for resource management and adaptation? Third, does downscaling enhance the degree of multi-model consistency at scales smaller than the typical global model resolution? We conclude by using these results to highlight requirements for further model development to make the next generation of models more useful for planning purposes.

Assessment of the impact of climate change on spatiotemporal variability of blue and green water resources under CMIP3 and CMIP5 models in a highly mountainous watershed

NASA Astrophysics Data System (ADS)

Fazeli Farsani, Iman; Farzaneh, M. R.; Besalatpour, A. A.; Salehi, M. H.; Faramarzi, M.

2018-04-01

The variability and uncertainty of water resources associated with climate change are critical issues in arid and semi-arid regions. In this study, we used the soil and water assessment tool (SWAT) to evaluate the impact of climate change on the spatial and temporal variability of water resources in the Bazoft watershed, Iran. The analysis was based on changes of blue water flow, green water flow, and green water storage for a future period (2010-2099) compared to a historical period (1992-2008). The r-factor, p-factor, R 2, and Nash-Sutcliff coefficients for discharge were 1.02, 0.89, 0.80, and 0.80 for the calibration period and 1.03, 0.76, 0.57, and 0.59 for the validation period, respectively. General circulation models (GCMs) under 18 emission scenarios from the IPCC's Fourth (AR4) and Fifth (AR5) Assessment Reports were fed into the SWAT model. At the sub-basin level, blue water tended to decrease, while green water flow tended to increase in the future scenario, and green water storage was predicted to continue its historical trend into the future. At the monthly time scale, the 95% prediction uncertainty bands (95PPUs) of blue and green water flows varied widely in the watershed. A large number (18) of climate change scenarios fell within the estimated uncertainty band of the historical period. The large differences among scenarios indicated high levels of uncertainty in the watershed. Our results reveal that the spatial patterns of water resource components and their uncertainties in the context of climate change are notably different between IPCC AR4 and AR5 in the Bazoft watershed. This study provides a strong basis for water supply-demand analyses, and the general analytical framework can be applied to other study areas with similar challenges.

Interactive Photochemistry in Earth System Models to Assess Uncertainty in Ozone and Greenhouse Gases. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prather, Michael J.; Hsu, Juno; Nicolau, Alex

Atmospheric chemistry controls the abundances and hence climate forcing of important greenhouse gases including N 2O, CH 4, HFCs, CFCs, and O 3. Attributing climate change to human activities requires, at a minimum, accurate models of the chemistry and circulation of the atmosphere that relate emissions to abundances. This DOE-funded research provided realistic, yet computationally optimized and affordable, photochemical modules to the Community Earth System Model (CESM) that augment the CESM capability to explore the uncertainty in future stratospheric-tropospheric ozone, stratospheric circulation, and thus the lifetimes of chemically controlled greenhouse gases from climate simulations. To this end, we have successfullymore » implemented Fast-J (radiation algorithm determining key chemical photolysis rates) and Linoz v3.0 (linearized photochemistry for interactive O 3, N 2O, NO y and CH 4) packages in LLNL-CESM and for the first time demonstrated how change in O2 photolysis rate within its uncertainty range can significantly impact on the stratospheric climate and ozone abundances. From the UCI side, this proposal also helped LLNL develop a CAM-Superfast Chemistry model that was implemented for the IPCC AR5 and contributed chemical-climate simulations to CMIP5.« less

Test of High-resolution Global and Regional Climate Model Projections

NASA Astrophysics Data System (ADS)

Stenchikov, Georgiy; Nikulin, Grigory; Hansson, Ulf; Kjellström, Erik; Raj, Jerry; Bangalath, Hamza; Osipov, Sergey

2014-05-01

In scope of CORDEX project we have simulated the past (1975-2005) and future (2006-2050) climates using the GFDL global high-resolution atmospheric model (HIRAM) and the Rossby Center nested regional model RCA4 for the Middle East and North Africa (MENA) region. Both global and nested runs were performed with roughly the same spatial resolution of 25 km in latitude and longitude, and were driven by the 2°x2.5°-resolution fields from GFDL ESM2M IPCC AR5 runs. The global HIRAM simulations could naturally account for interaction of regional processes with the larger-scale circulation features like Indian Summer Monsoon, which is lacking from regional model setup. Therefore in this study we specifically address the consistency of "global" and "regional" downscalings. The performance of RCA4, HIRAM, and ESM2M is tested based on mean, extreme, trends, seasonal and inter-annual variability of surface temperature, precipitation, and winds. The impact of climate change on dust storm activity, extreme precipitation and water resources is specifically addressed. We found that the global and regional climate projections appear to be quite consistent for the modeled period and differ more significantly from ESM2M than between each other.

Tropical Andean ecosystems and the need to keep warming limits below a +1.5°C threshold

NASA Astrophysics Data System (ADS)

Ruiz-Carrascal, D.; Herzog, S. K.; Guitierrez Lagoueyte, M. E.; Gonzalez-Duque, D.; Cuevas-Moreno, J.; del Valle, J. I.; Andreu-Hayles, L.; Herrera, D. A.; Martínez, R.

2017-12-01

Long-term climate change and rapid land-use change are synergistically threatening the integrity and functioning of tropical Andean ecosystems. The main goal of our research was to integrate climate change projections, biodiversity data and anthropogenically driven ecosystem disruption assessments to quantify the vulnerability of Andean ecosystems and species to global change at a local scale. We merged discernible trends in local quality-controlled weather station data with reanalysis data, as well as with historical and prospective simulation outputs of five well-known GCMs to assess a long-term context for the analysis of climate change exposure (temperature severity intervals). Individual, medium-term, multi-member GCM simulations included: altitude-corrected 2046-2065 (IPCC-AR4) climate change scenarios for the A1B emission scenario; and spatially-downscaled 2040-2069 (IPCC-AR5) projections for the RCP4.5. Previous studies reported mean annual temperature anomaly intervals that resulted in exceedingly high thresholds: the lowest severity interval (< +2.06°C) and the highest (> +2.71°C). The least severe interval extended up to the threshold widely recognized as `dangerous' climate change, thereby leading to an underestimation of the true vulnerability of Andean species. Our analyses suggest that temperature anomalies for the full extent of the tropical Andes will likely range from low (< +1.60°C) to high (> +2.61°C), exceeding the threshold of 'natural' climate variability (+1.78°C). Our results suggest that most species that were used as proxies of ecosystem vulnerabilities will likely experience overall low-to-medium-to-high temperature increases. Since many of them have potentially high sensitivity to such long-term changes, Andean species will likely experience greatly increases in vulnerability. The already-disrupted Andean ecosystems will suffer a further climatic stress, which will worsen the well-known detrimental synergies between climate and land-use changes. There is an imperative need to prioritize high-risk areas for the implementation of conservation and adaptation actions. Equally important, there is an urgent need to keep warming limits well below 2.0°C, ideally below +1.5°C, if we expect to preserve the integrity of our unique Andean environments.

From up to date climate and ocean evidence with updated UN emissions projections, the time is now to recommend an immediate massive effort on CO2.

NASA Astrophysics Data System (ADS)

Carter, Peter

2017-04-01

This paper provides further compelling evidence for 'an immediate, massive effort to control CO2 emissions, stopped by mid-century' (Cai, Lenton & Lontzek, 2016). Atmospheric CO2 which is above 405 ppm (actual and trend) still accelerating, despite flat emissions since 2014, with a 2015 >3ppm unprecedented spike in Earth history (A. Glikson),is on the worst case IPCC scenario. Atmospheric methane is increasing faster than its past 20-year rate, almost on the worst-case IPCC AR5 scenario (Global Carbon Project, 2016). Observed effects of atmospheric greenhouse gas (GHG) pollution are increasing faster. This includes long-lived atmospheric GHG concentrations, radiative forcing, surface average warming, Greenland ice sheet melting, Arctic daily sea ice anomaly, ocean heat (and rate of going deeper), ocean acidification, and ocean de-oxygenation. The atmospheric GHG concentration of 485 ppm CO2 eq (WMO, 2015) commits us to 'about 2°C' equilibrium (AR5). 2°C by 2100 would require 'substantial emissions reductions over the next few decades' (AR5). Instead, the May 2016 UN update on 'intended' national emissions targets under the Paris Agreement projects global emissions will be 16% higher by 2030 and the November 2016 International Energy Agency update projects energy-related CO2 eq emissions will be 30% higher by 2030, leading to 'around 2.7°C by 2100 and above 3°C thereafter'. Climate change feedback will be positive this century and multiple large vulnerable sources of amplifying feedback exist (AR5). 'Extensive tree mortality and widespread forest die-back linked to drought and temperature stress have been documented on all vegetated continents' (AR5). 'Recent studies suggest a weakening of the land sink, further amplifying atmospheric growth of CO2' (WMO, 2016). Under all but the best-case IPCC AR5 scenario, surface temperature is projected to increase above 2°C by 2100, which is above 3°C (equilibrium) after 2100, with ocean acidification still increasing at 2100. Ocean heat is increasing under all scenarios at 2100. For all producing regions 'With or without adaptation, negative impacts on average crop yields become likely from the 2030s' (AR5). Crop models do not capture all adverse effects. The climate change of 2030 is practically locked in. NASA NEX downscaled daily maximum temperature projections at 1.5°C are incompatible with today's crop yields in major agricultural regions. Climate-change-related impacts from extreme events are high at 1.5°C (AR5) and add to modeled crop declines. 'Some unique and threatened systems are already at risk from climate change (high confidence)' with 'risk of severe consequences' higher with warming of around 1.5°C (AR5). At today's surface temperature increase, 'risks associated with tipping points become moderate' and 'increase disproportionately' as temperature increases above 1.5°C (AR5). According to mitigation projections, global emissions would decline forthwith for a better than 66% chance of a 2°C limit by 2100 (over 3°C after 2100). Failure to do so would risk the future sustainability of civilization and the human population. The IPCC does not make recommendations so this falls on scientists. By recommending immediate (emergency) massive action on CO2, the science community would make a momentous contribution to the future of humanity.

Assessment of NASA GISS CMIP5 ModelE simulated clouds and TOA radiation budgets using satellite observations over the southern mid-latitudes

NASA Astrophysics Data System (ADS)

Stanfield, Ryan Evan

Past, current, and future climates have been simulated by the National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies (GISS) ModelE Global Circulation Model (GCM) and summarized by the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC, AR4). New simulations from the updated CMIP5 version of the NASA GISS ModelE GCM were recently released to the public community during the summer of 2011 and will be included in the upcoming IPCC AR5 ensemble of simulations. Due to the recent nature of these simulations, they have not yet been extensively validated against observations. To assess the NASA GISS-E2-R GCM, model simulated clouds and cloud properties are compared to observational cloud properties derived from the Clouds and Earth's Radiant Energy System (CERES) project using MODerate Resolution Imaging Spectroradiometer (MODIS) data for the period of March 2000 through December 2005. Over the 6-year period, the global average modeled cloud fractions are within 1% of observations. However, further study however shows large regional biases between the GCM simulations and CERES-MODIS observations. The southern mid-latitudes (SML) were chosen as a focus region due to model errors across multiple GCMs within the recent phase 5 of the Coupled Model Intercomparison Project (CMIP5). Over the SML, the GISS GCM undersimulates total cloud fraction over 20%, but oversimulates total water path by 2 g m-2. Simulated vertical cloud distributions over the SML when compared to both CERES-MODIS and CloudSat/CALIPSO observations show a drastic undersimulation of low level clouds by the GISS GCM, but higher fractions of thicker clouds. To assess the impact of GISS simulated clouds on the TOA radiation budgets, the modeled TOA radiation budgets are compared to CERES EBAF observations. Because modeled low-level cloud fraction is much lower than observed over the SML, modeled reflected shortwave (SW) flux at the TOA is 13 W m -2 lower and outgoing longwave radiation (OLR) is 3 W m-2 higher than observations. Finally, cloud radiative effects (CRE) are calculated and compared with observations to fully assess the impact of clouds on the TOA radiation budgets. The difference in clear-sky reflected SW flux between model and observation is only +4 W m-2 while the SW CRE difference is up to 17 W m-2, indicating that most of the bias in SW CRE results from the all-sky bias between the model and observation. A sizeable negative bias of 10 W m-2 in simulated clear-sky OLR has been found due to a dry bias in calculating observed clear-sky OLR and lack of upper-level water vapor at the 100-mb level in the model. The dry bias impacts CRE LW, with the model undersimulating by 13 W m-2. The CRE NET difference is only 5 W m-2 due to the cancellation of SW and LW CRE biases.

Reassessing Storm Surge Risk for New York City (Invited)

NASA Astrophysics Data System (ADS)

Lin, N.; Emanuel, K.

2013-12-01

New York City (NYC) is highly vulnerable to tropical cyclone (TC) storm surge flooding. In a previous study, we coupled a (reanalysis- or GCM-driven) hurricane model with hydrodynamic models to simulate large numbers of synthetic surge events under observed and projected climates and assess surge threat for NYC. The storm surge return levels under the current and future climates (IPCC AR4 A1B scenario) were obtained. The results showed that the distribution of surge levels may shift to higher values in the future by a magnitude comparable to the projected sea-level rise. The study focused on typical TCs that have a storm size of the climatological mean for the Atlantic Basin and pass within a 200-km radius of the Battery, NYC. In October 2012, Hurricane Sandy, a barely Category-1 storm that made landfall about 200-km southwest from the Battery, caused the highest surge flooding of the instrumental record (~3.5 m above the mean sea level or ~2.8 m surge over the high tide) at the Battery. The extreme surge was due to the fact that the storm was a 'hybrid' event, undergoing extensive extratropical transition when making landfall almost perpendicularly to the NJ coast with an unusually large size. Sandy's case calls for a reassessment of storm surge risk for NYC that account for the special features of the storms in this region. In this reassessment, we account for the effect of extratropical transition on the wind fields through improving the surface background wind estimation, which was assumed to be uniform for typical TCs, by developing a representation of the interaction between the highly localized potential vorticity anomaly of the TC and its environmental baroclinic fields. We account for the storm size variation through incorporating the full probability distribution of the size for the region. Our preliminary results show that estimated wind and surge return levels are much higher with the effect of extratropical transition. The effect of the storm size variation is relatively large in the upper tail of the surge distribution. Also, we will update the prediction for future climates using the IPCC AR5 RCP 8.5 and RCP 4.5 scenarios, and extend our focus area further south to capture storms that can induce high surges at the Battery, although making landfall relatively further away on the NJ coast. The results will be compared with those using the AR4 scenario in our previous study. The combined effects of storm climatology change and sea level rise on the risk of NYC surge flooding will be discussed.

Predicting the Arctic Ocean Environment in the 21st century

NASA Astrophysics Data System (ADS)

Aksenov, Yevgeny; Popova, Ekaterina; Yool, Andrew; Nurser, George

2015-04-01

Recent environmental changes in the Arctic have clearly demonstrated that climate change is faster and more vigorously in the Polar Regions than anywhere else. Significantly, change in the Arctic Ocean (AO) environment presents a variety of impacts, from ecological to social-economic and political. Mitigation of this change and adaptation to it requires detailed and robust environmental predictions. Here we present a detailed projection of ocean circulation and sea ice from the present until 2099, based on an eddy-permitting high-resolution global simulation of the NEMO ¼ degree ocean model. The model is forced at the surface with HadGEM2-ES atmosphere model output from the UK Met. Office IPCC Assessment Report 5 (AR5) Representative Concentration Pathways 8.5 (RCP8.5) scenario. The HadGEM2-ES simulations span 1860-2099 and are one of an ensemble of runs performed for the Coupled Model Intercomparison Project 5 (CMIP5) and IPCC AR5. Between 2000-2009 and 2090-2099 the AO experiences a significant warming, with sea surface temperature increasing on average by about 4° C, particularly in the Barents and Kara Seas, and in the Greenland Sea and Hudson Bay. By the end of the simulation, Arctic sea ice has an average annual thickness of less than 10 cm in the central AO, and less than 0.5 m in the East-Siberian Sea and Canadian Archipelago, and disappears entirely during the Arctic summer. In summer, opening of large areas of the Arctic Ocean to the wind and surface waves leads to the Arctic pack ice cover evolving into the Marginal Ice Zone (MIZ). In winter, sea ice persists until the 2030s; then it sharply declines and disappears from the Central Arctic Ocean by the end of the 21st century, with MIZ provinces remaining in winter along the Siberian, Alaskan coasts and in the Canadian Arctic Archipelago. Analysis of the AO circulation reveals evidence of (i) the reversal of the Arctic boundary currents in the Canadian Basin, from a weak cyclonic current in 2040-2049 to a strong anti-cyclonic current in 2090-2099, and (ii) increased anti-cyclonic surface ocean circulation in the eastern part of the AO, while the surface circulation in the western Arctic becomes more cyclonic. We relate the shift in the circulation to changes in the winds and reduction of sea ice cover, which modify momentum transfer from atmosphere to the ocean. Our simulation suggests a potentially complex picture of future AO change, and highlights the importance of high resolution modelling in forecasting it.

Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

NASA Astrophysics Data System (ADS)

Cannaby, Heather; Palmer, Matthew D.; Howard, Tom; Bricheno, Lucy; Calvert, Daley; Krijnen, Justin; Wood, Richard; Tinker, Jonathan; Bunney, Chris; Harle, James; Saulter, Andrew; O'Neill, Clare; Bellingham, Clare; Lowe, Jason

2016-05-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time-mean sea level were evaluated using the process-based climate model data and methods presented in the United Nations Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Regional surge and wave solutions extending from 1980 to 2100 were generated using ˜ 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled ( ˜ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980 to 2010, enabling a quantitative assessment of model skill. Simulated historical sea-surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data, respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the Representative Concentration Pathway (RCP)4.5 (8.5) scenarios. Trends in surge and significant wave height 2-year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of ˜ 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Stephen E.; Charlson, Robert J.; Kahn, Ralph

Earth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re-examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content.more » This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO₂ given in AR5, 1.5–4.5 K/(3.7 W m⁻²) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m⁻²), where 3.7 W ⁻² denotes the forcing for doubled CO₂. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.« less

Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

DOE PAGES

Schwartz, Stephen E.; Charlson, Robert J.; Kahn, Ralph; ...

2014-12-08

Earth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re-examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content.more » This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO₂ given in AR5, 1.5–4.5 K/(3.7 W m⁻²) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m⁻²), where 3.7 W ⁻² denotes the forcing for doubled CO₂. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.« less

Analyses of Projected Changes in Climate for Sub-Saharan Africa Using a Variable-Resolution Atmospheric Model

NASA Astrophysics Data System (ADS)

Adegoke, J.; Engelbrecht, F.; Vezhapparambu, S.

2012-12-01

The conformal-cubic atmospheric model (CCAM) is employed in this study as a flexible downscaling tool at the climate-change time scale. In the downscaling procedure, the sea-ice and bias-corrected SSTs of 6 CGCMs (CSIRO Mk 3.5, GFDL2.1, GFDL2.0, HadCM2, ECHAM5 and Miroc-Medres) from AR4 of the IPCC were first used as lower-boundary forcing in CCAM simulations performed at a quasi-uniform resolution (about 200 km in the horizontal), which were subsequently downscaled to a resolution of about 60 km over southern and tropical Africa. All the simulations were for the A2 scenario of the Special Report on Emission Scenarios (SRES), and for the period 1961-2100. The SST biases were derived by comparing the simulated and observed present-day climatol¬ogy of SSTs for 1979-1999 for each month of the year; the same monthly bias corrections were applied for the duration of the simulations. CCAM ensemble projected change in annual average temperature and Rainfall for 2071-2100 vs 1961-1990 for tropical Africa will be presented and discussed. In summary, a robust signal of drastic increases in surface temperature (more than 3 degrees C for the period 2071-2100 relative to 1961-1990) is projected across the domain. Temperature increases as large as 5 degrees C are projected over the subtropical regions in the north of the domain. Increase in rainfall over tropical Africa (for the period 2071-2100 relative to 1961-1990) is projected across the domain. This is consistent with an increase in moisture in a generally warmer atmosphere. There is a robust signal of drying along the West African coast - however, the CMIP3 CGCM projections indicate a wide range of possible rainfall futures over this region The projections of East Africa becoming wetter is robust across the CCAM ensemble, consistent with the CGCM projections of CMIP3 and AR4.

The Uptake of Heat and Carbon by the Southern Ocean in the CMIP5 Earth System Models

NASA Astrophysics Data System (ADS)

Russell, J. L.; Stouffer, R. J.; Dunne, J. P.; John, J. G.

2011-12-01

The Southern Ocean surrounding the Antarctic continent accounts for a disproportionate share of the heat and carbon dioxide that is removed from contact with the atmosphere into the ocean. The vigorous air-sea exchange driven by the Southern Hemisphere Westerlies, combined with the dearth of observations, makes the Southern Ocean a major source of uncertainty in projecting the rate of warming of our atmosphere, especially considering that the vertical mixing of the ocean and the corollary air-sea fluxes may be vulnerable to climate change. We assess the heat and carbon uptake by the Southern Ocean in future simulations by the IPCC-AR5 Earth System Models (ESMs), focusing on the GFDL simulations. Using the 1860 control simulation as our baseline, we explore the differences in heat and carbon uptake between the major "Representative Concentration Pathways" (RCPs) as simulated by the various ESMs in order to quantify the uncertainties in the climate projections related to the Southern Ocean window into the deep ocean reservoir.

Simulating Soil C Stock with the Process-based Model CQESTR

NASA Astrophysics Data System (ADS)

Gollany, H.; Liang, Y.; Rickman, R.; Albrecht, S.; Follett, R.; Wilhelm, W.; Novak, J.; Douglas, C.

2009-04-01

The prospect of storing carbon (C) in soil, as soil organic matter (SOM), provides an opportunity for agriculture to contribute to the reduction of carbon dioxide in the atmosphere while enhancing soil properties. Soil C models are useful for examining the complex interactions between crop, soil management practices and climate and their effects on long-term carbon storage or loss. The process-based carbon model CQESTR, pronounced ‘sequester,' was developed by USDA-ARS scientists at the Columbia Plateau Conservation Research Center, Pendleton, Oregon, USA. It computes the rate of biological decomposition of crop residues or organic amendments as they convert to SOM. CQESTR uses readily available field-scale data to assess long-term effects of cropping systems or crop residue removal on SOM accretion/loss in agricultural soil. Data inputs include weather, above- ground and below-ground biomass additions, N content of residues and amendments, soil properties, and management factors such as tillage and crop rotation. The model was calibrated using information from six long-term experiments across North America (Florence, SC, 19 yrs; Lincoln, NE, 26 yrs; Hoytville, OH, 31 yrs; Breton, AB, 60 yrs; Pendleton, OR, 76 yrs; and Columbia, MO, >100 yrs) having a range of soil properties and climate. CQESTR was validated using data from several additional long-term experiments (8 - 106 yrs) across North America having a range of SOM (7.3 - 57.9 g SOM/kg). Regression analysis of 306 pairs of predicted and measured SOM data under diverse climate, soil texture and drainage classes, and agronomic practices at 13 agricultural sites resulted in a linear relationship with an r2 of 0.95 (P < 0.0001) and a 95% confidence interval of 4.3 g SOM/kg. Estimated SOC values from CQESTR and IPCC (the Intergovernmental Panel on Climate Change) were compared to observed values in three relatively long-term experiments (20 - 24 years). At one site, CQESTR and IPCC estimates of SOC stocks were within 5% of each other for three rotations. At a second site, decreasing tillage intensity increased SOC stocks for winter wheat-fallow rotation for both observed and estimated values by CQESTR and IPCC. At the third site, CQESTR simulated an increase in SOC stocks with increased fertility levels, while IPCC estimates of SOC stocks did not reflect an increase. The CQESTR model successfully predicts SOM dynamics from various management practices and offers the potential for C sequestration planning for C credits or to guide crop residue removal for bio-energy production without degrading the soil resource, environmental quality, or productivity.

Comparisons of Radiative Flux Distributions from Satellite Observations and Global Models

NASA Astrophysics Data System (ADS)

Raschke, Ehrhard; Kinne, Stefan; Wild, Martin; Stackhouse, Paul; Rossow, Bill

2014-05-01

Radiative flux distributions at the top of the atmosphere (TOA) and at the surface are compared between typical data from satellite observations and from global modeling. Averages of CERES, ISCCP and SRB data-products (for the same 4-year period) represent satellite observations. Central values of IPCC-4AR output (over a 12-year period) represent global modeling. At TOA, differences are dominated by differences for cloud-effects, which are extracted from the differences between all-sky and clear-sky radiative flux products. As satellite data are considered as TOA reference, these differences document the poor representation of clouds in global modeling, especially for low altitude clouds over oceans. At the surface the differences, caused by the different cloud treatment are overlaid by a general offset. Satellite products suggest a ca 15Wm-2 stronger surface net-imbalance (and with it stronger precipitation). Since surface products of satellite and modeling are based on simulations and many assumptions, this difference has remained an open issue. BSRN surface monitoring is too short and too sparsely distributed for clear answers to provide a reliable basis for validation.

Land-Use and Climate : first results from the LUCID experiments ; implications for experimental design in IPCC-AR5

NASA Astrophysics Data System (ADS)

de Noblet, N.; Pitman, A.; Participants, Lucid

2009-04-01

The project "Land-Use and Climate, IDentification of robust impacts" (LUCID) was conceived under the auspices of IGBP-iLEAPS and GEWEX-GLASS, to address the robustness of 'local' and possible remote impacts of land-use induced land-cover changes (LCC). LUCID explores, using methodologies that major climate modelling groups recognise, those impacts of LCC that are robust - that is, above the noise generated by model variability and consistent across a suite of climate models. To start with, seven climate models were run, in ensemble mode (5 realisations per 31-years long experiment), with prescribed observed sea-surface temperatures (SSTs) and sea ice extent (SIc). Pre-industrial and present-day simulations were used to explore the impacts of biogeophysical impacts of human-induced land cover change. The imposed LCC perturbation led to statistically significant changes in latent heat flux and near-surface temperature over the regions of land cover change, but few significant changes in precipitation. Our results show no common remote impacts of land cover change. They also highlight a dilemma for both historical hind-casts and future projections; land cover change is regionally important, but it is not feasible within the time frame of the next IPCC (AR5) assessment to implement this change commonly across multiple models. Further analysis are in progress and will be presented to identify the continental regions where changes in LCC may have been more important than the combined changes in SSTs, SIc and CO2 between the pre-industrial times and nowadays.

Impacts of climate change on growth period and planting boundaries of winter wheat in China under RCP4.5 scenario

NASA Astrophysics Data System (ADS)

Sun, Z.; Jia, S. F.; Lv, A. F.; Yang, K. J.; Svensson, J.; Gao, Y. C.

2015-10-01

This paper advances understanding of the impacts of climate change on crops in China by moving from ex-post analysis to forecasting, and by demonstrating how the effects of climate change will affect the growth period and the planting boundaries of winter wheat. Using a multiple regression model based on agricultural meteorological observations and the IPCC AR5 GCMs simulations, we find that the sowing date of winter wheat in the base period, 2040s and 2070s, shows a gradually delayed trend from north to south and the growth period of winter wheat in China will be shortened under climate change. The simulation results also show that (i) the north planting boundaries of winter wheat in China will likely move northward and expand westward in the future, while the south planting boundary will rise and spread in south Hainan and Taiwan; and (ii) the Xinjiang Uygur Autonomous Region and the Inner Mongolia Autonomous Region will have the largest increases in planting areas in 2040s and 2070s. Our simulation implies that Xinjiang and Inner Mongolia are more sensitive to climate change than other regions in China and priority should be given to design adaptation strategies for winter wheat planting for these provinces.

Impacts of changes in climate and land use/land cover under IPCC RCP scenarios on streamflow in the Hoeya River Basin, Korea.

PubMed

Kim, Jinsoo; Choi, Jisun; Choi, Chuluong; Park, Soyoung

2013-05-01

This study examined the separate and combined impacts of future changes in climate and land use/land cover (LULC) on streamflow in the Hoeya River Basin, South Korea, using the representative concentration pathway (RCP) 4.5 and 8.5 scenarios of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). First, a LULC change model was developed using RCP 4.5 and RCP 8.5 storylines and logistic regression. Three scenarios (climate change only, LULC change only, and climate and LULC change combined) were established, and the streamflow in future periods under these scenarios was simulated by the Soil and Water Assessment Tool (SWAT) model. Each scenario showed distinct seasonal variations in streamflow. Under climate change only, streamflow increased in spring and winter but decreased in summer and autumn, whereas LULC change increased high flow during wet periods but decreased low flow in dry periods. Although the LULC change had less effect than climate change on the changes in streamflow, the effect of LULC change on streamflow was significant. The result for the combined scenario was similar to that of the climate change only scenario, but with larger seasonal changes in streamflow. Although the effects of LULC change were smaller than those caused by climate change, LULC changes may heighten the problems of increased seasonal variability in streamflow caused by climate change. The results obtained in this study provide further insight into the availability of future streamflow and can aid in water resource management planning in the study area. Copyright © 2013 Elsevier B.V. All rights reserved.

The Obama - Xi Accord: A Need for Further Action

NASA Astrophysics Data System (ADS)

Tribett, W. R.; Hope, A. P.; Canty, T. P.; Salawitch, R. J.

2015-12-01

Presidents Barrack Obama of the United States and Jinping Xi of China recently announced a bilateral framework to reduce the total carbon emissions of their respective countries. The U.S. agreed to reduce annual carbon emissions such that by 2025, emissions would be 27% below 2005 levels. China agreed to achieve peak carbon emissions around 2030 coupled with a best effort to peak early. Here we analyze the implications of the Obama-Xi accord for total global carbon emissions (GCE) out to year 2060, using projections of population, economic growth, and carbon intensity for the rest of the world as well as various assumptions regarding how emissions from the U.S. and China will evolve after the timeframe of the Obama-Xi accord. Our GCE projections will be compared to those of the four Representative Concentration Pathway (RCP) emission scenarios used in the IPCC Fifth Assessment Report (AR5). The Obama-Xi accord is shown to be a meaningful first step: if followed, the actual GCE will likely fall below RCP 8.5 between now and 2060. The U.S., China, and rest of the world presently emit 4.5, 2.0, and 1.1 tonne of carbon per person per year (tpy), respectively. We show that if the world's nations adopt a strategy of "Contraction and Convergence", such that per capita emission for each country reaches 1.0 tpy by 2060, actual GCE will approach that of RCP 4.5 by year 2060. Such action may be needed to reduce the risk of the most dire global warming forecasts within IPCC AR5.

Rainfall and its seasonality over the Amazon in the 21st century as assessed by the coupled models for the IPCC AR4

NASA Astrophysics Data System (ADS)

Li, Wenhong; Fu, Rong; Dickinson, Robert E.

2006-01-01

The global climate models for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) predict very different changes of rainfall over the Amazon under the SRES A1B scenario for global climate change. Five of the eleven models predict an increase of annual rainfall, three models predict a decrease of rainfall, and the other three models predict no significant changes in the Amazon rainfall. We have further examined two models. The UKMO-HadCM3 model predicts an El Niño-like sea surface temperature (SST) change and warming in the northern tropical Atlantic which appear to enhance atmospheric subsidence and consequently reduce clouds over the Amazon. The resultant increase of surface solar absorption causes a stronger surface sensible heat flux and thus reduces relative humidity of the surface air. These changes decrease the rate and length of wet season rainfall and surface latent heat flux. This decreased wet season rainfall leads to drier soil during the subsequent dry season, which in turn can delay the transition from the dry to wet season. GISS-ER predicts a weaker SST warming in the western Pacific and the southern tropical Atlantic which increases moisture transport and hence rainfall in the Amazon. In the southern Amazon and Nordeste where the strongest rainfall increase occurs, the resultant higher soil moisture supports a higher surface latent heat flux during the dry and transition season and leads to an earlier wet season onset.

Climate change and Mediterranean storm tracks: present and future climate simulations of a high-resolution Mediterranean model

NASA Astrophysics Data System (ADS)

Hatzaki, M.; Flocas, H. A.; Simmonds, I.; Keay, K.; Giannakopoulos, C.; Brikolas, V.; Kouroutzoglou, J.

2010-09-01

A number of studies suggest that cyclone activity over both hemispheres has changed over the second half of the 20th century. General features include a reduction in the number of cyclones but with an increase in the number of more intense cyclones; as well as a poleward shift in the tracks. Moreover, these features are expected to be projected in the future under global warming conditions. The assessment of the future changes of the cyclonic activity as imposed by global warming conditions is very important since these cyclones can be associated with extreme precipitation conditions, severe storms and floods. This is more important for the Mediterranean that has been found to be more vulnerable to climate change. The main objective of the current study is to better understand and assess future changes in the main characteristics of cyclonic tracks in the Mediterranean. The climatology of the cyclonic tracks includes temporal and spatial variations of frequency, and dynamic and kinematic parameters, such as intensity, size, propagation velocity, as well as trend analysis. For this purpose, the ENEA high resolution model is employed, based on PROTHEUS system composed of the RegCM atmospheric regional model and the MITgcm ocean model, coupled through the OASIS3 flux coupler. These model data became available through the EU Project CIRCE which aims to perform, for the first time, climate change projections with a realistic representation of the Mediterranean Sea. Two experiments are employed; a) the EH5OM_20C3M present climate simulation, where the lateral boundary conditions for the atmosphere (1951-2000) are taken from the ECHAM5-MPIOM 20c3m global simulation (run3) included in the IPCC-AR4, and b) the EH5OM_A1B scenario simulation, where the IPCC-AR4 ECHAM5-MPIOM SRESA1B global simulation (run3) has been used for the period 2001-2050. The identification and tracking of cyclones is performed with the aid of the Melbourne University algorithm (MS algorithm), according to the Lagrangian perspective. MS algorithm characterizes a cyclone only if a vorticity maximum could be connected with a local pressure minimum. This approach is considered to be crucial, since open lows are also incorporated into the storm life-cycle, preventing possible inappropriate time series breaks, if a temporary weakening to an open-low state occurs. According to the results, a decrease of the storm number and a tendency towards deeper cyclones is expected in the future, in general agreement with the results of previous studies. However, new findings reveal with respect to the dynamic/kinematic characteristics of the cyclonic tracks. ACKNOWLEDGMENTS: M. Hatzaki would like to thank the Greek State Scholarships Foundation for financial support through the program of postdoctoral research. The support of EU-FP6 project CIRCE Integrated Project-Climate Change and Impact Research: the Mediterranean Environment (http://www.circeproject.eu) for climate model data provision is also greatly acknowledged.

Climate Products and Services to Meet the Challenges of Extreme Events

NASA Astrophysics Data System (ADS)

McCalla, M. R.

2008-12-01

The 2002 Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM1)-sponsored report, Weather Information for Surface Transportation: National Needs Assessment Report, addressed meteorological needs for six core modes of surface transportation: roadway, railway, transit, marine transportation/operations, pipeline, and airport ground operations. The report's goal was to articulate the weather information needs and attendant surface transportation weather products and services for those entities that use, operate, and manage America's surface transportation infrastructure. The report documented weather thresholds and associated impacts which are critical for decision-making in surface transportation. More recently, the 2008 Climate Change Science Program's (CCSP) Synthesis and Assessment Product (SAP) 4.7 entitled, Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study, Phase I, included many of the impacts from the OFCM- sponsored report in Table 1.1 of this SAP.2 The Intergovernmental Panel on Climate Change (IPCC) reported that since 1950, there has been an increase in the number of heat waves, heavy precipitation events, and areas of drought. Moreover, the IPCC indicated that greater wind speeds could accompany more severe tropical cyclones.3 Taken together, the OFCM, CCSP, and IPCC reports indicate not only the significance of extreme events, but also the potential increasing significance of many of the weather thresholds and associated impacts which are critical for decision-making in surface transportation. Accordingly, there is a real and urgent need to understand what climate products and services are available now to address the weather thresholds within the surface transportation arena. It is equally urgent to understand what new climate products and services are needed to address these weather thresholds, and articulate what can be done to fill the gap between the existing federal climate products and services and the needed federal climate products and services which will address these weather thresholds. Just as important, as we work to meet the needs, a robust education and outreach program is essential to take full advantage of new products, services and capabilities. To ascertain what climate products and services currently exist to address weather thresholds relative to surface transportation, what climate products and services are needed to address these weather thresholds, and how to bridge the gap between what is available and what is needed, the OFCM surveyed the federal meteorological community. Consistent with the extreme events highlighted in the IPCC report, the OFCM survey categorized the weather thresholds associated with surface transportation into the following extreme event areas: (a) excessive heat, (b) winter precipitation, (c) summer precipitation, (d) high winds, and (e) flooding and coastal inundation. The survey results, the gap analysis, as well as OFCM's planned, follow-on activities with additional categories (i.e., in addition to surface transportation) and weather thresholds will be shared with meeting participants. 1 The OFCM is an interdepartmental office established in response to Public Law 87-843 with the mission to ensure the effective use of federal meteorological resources by leading the systematic coordination of operational weather and climate requirements, products, services, and supporting research among the federal agencies. 2 http://www.climatescience.gov/Library/sap/sap4-7/final-report/sap4-7-final-ch1.pdf 3 http://www.gcrio.org/ipcc/ar4/wg1/faq/ar4wg1faq-3-3.pdf

Hydrodynamic evaluation of long term impacts of climate change and coastal effluents in the Arabian Gulf.

PubMed

Elhakeem, Abubaker; Elshorbagy, Walid

2015-12-30

A comprehensive basin wide hydrodynamic evaluation has been carried out to assess the long term impacts of climate change and coastal effluents on the salinity and seawater temperature of the Arabian Gulf (AG) using Delft3D-Flow model. The long term impacts of climate change scenarios A2 and B1 of the IPCC-AR4 on the AG hydrodynamics were evaluated. Using the current capacity and production rates of coastal desalination, power, and refinery plants, two projection scenarios until the year 2080 with 30 year intervals were developed namely the realistic and the optimistic discharge scenarios. Simulations of the individual climate change scenarios ascertained overall increase of the AG salinity and temperature and decrease of precipitation. The changes varied spatially with different scenarios as per the depth, proximity to exchange with ocean water, flushing, vertical mixing, and flow restriction. The individual tested scenarios of coastal projected discharges showed significant effects but within 10-20 km from the outfalls. Copyright © 2015 Elsevier Ltd. All rights reserved.

Emulating atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 - Part 2: Applications

NASA Astrophysics Data System (ADS)

Meinshausen, M.; Wigley, T. M. L.; Raper, S. C. B.

2011-02-01

Intercomparisons of coupled atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models are important for galvanizing our current scientific knowledge to project future climate. Interpreting such intercomparisons faces major challenges, not least because different models have been forced with different sets of forcing agents. Here, we show how an emulation approach with MAGICC6 can address such problems. In a companion paper (Meinshausen et al., 2011a), we show how the lower complexity carbon cycle-climate model MAGICC6 can be calibrated to emulate, with considerable accuracy, globally aggregated characteristics of these more complex models. Building on that, we examine here the Coupled Model Intercomparison Project's Phase 3 results (CMIP3). If forcing agents missed by individual AOGCMs in CMIP3 are considered, this reduces ensemble average temperature change from pre-industrial times to 2100 under SRES A1B by 0.4 °C. Differences in the results from the 1980 to 1999 base period (as reported in IPCC AR4) to 2100 are negligible, however, although there are some differences in the trajectories over the 21st century. In a second part of this study, we consider the new RCP scenarios that are to be investigated under the forthcoming CMIP5 intercomparison for the IPCC Fifth Assessment Report. For the highest scenario, RCP8.5, relative to pre-industrial levels, we project a median warming of around 4.6 °C by 2100 and more than 7 °C by 2300. For the lowest RCP scenario, RCP3-PD, the corresponding warming is around 1.5 °C by 2100, decreasing to around 1.1 °C by 2300 based on our AOGCM and carbon cycle model emulations. Implied cumulative CO2 emissions over the 21st century for RCP8.5 and RCP3-PD are 1881 GtC (1697 to 2034 GtC, 80% uncertainty range) and 381 GtC (334 to 488 GtC), when prescribing CO2 concentrations and accounting for uncertainty in the carbon cycle. Lastly, we assess the reasons why a previous MAGICC version (4.2) used in IPCC AR4 gave roughly 10% larger warmings over the 21st century compared to the CMIP3 average. We find that forcing differences and the use of slightly too high climate sensitivities inferred from idealized high-forcing runs were the major reasons for this difference.

Interpolation and Meta-Analysis of IPCC AR4 General Circulation Model Scenarios applied to North America

NASA Astrophysics Data System (ADS)

Price, D. T.; Joyce, L. A.; McKenney, D. W.

2009-12-01

Projections of future climate simulated by four state-of-art general circulation models (GCM), namely the U.S. NCAR CCSM 3.0, Canadian CGCM 3.1, Australian CSIRO Mk. 3.5 and Japanese MIROC 3.2, forced by each of the IPCC AR4 SRA2, SRB1 and SRA1B greenhouse gas (GHG) emissions scenarios, were downscaled for Canada and the continental USA. For each GCM projection, monthly climate values for a rectangle covering North America were interpolated using ANUSPLIN (e.g., Hutchinson 1995), to a common 0.0833° geographic grid. The resulting 12 high resolution scenarios provide projected change factors for monthly solar radiation, windspeed and vapor pressure, air temperature and precipitation, for the 21st century, referenced to the averages of simulated monthly means for 1961-1990. The 12 interpolated scenario data sets were subjected to a meta-analysis. Data for each projected variable of each climate scenario were averaged for three consecutive 30-year periods (starting in 2011), to create scenario maps of changes in annual and seasonal means. The contiguous 48 U.S. States were grouped into seven regions based on the classification of Bailey (1994), with Alaska forming an eighth region, while Canada was divided into twelve regions based on the Canadian Terrestrial Ecozones (Wiken, 1986). In each region, data were spatially averaged (with area-weighting) and used to create graphs and summary tables of annual and seasonal trends, including long-term changes in interannual variability. Overall, the meta-analysis showed remarkable agreement among the four GCMs, in terms both of their sensitivity to increasing GHG forcing (SRB1→SRA1B→SRA2) and in the relative magnitudes of the climate changes projected for each scenario in each region. Temperatures were projected to increase by 2-4 °C in the southern USA (summer) to as much as 4-8 °C in northern Canada and Alaska (winter minima), by the mid-2080s, relative to 2000. Precipitation was projected to increase by 5-10% over the same period, but with distinct seasonal trends that differed among regions; one GCM projected significant decreases in precipitation in the southern USA. Solar radiation inputs were generally projected to decline slightly, showing consistent inverse relationships to projected precipitation changes, while vapor pressure generally increased, particularly in summer and particularly in coastal regions. Projected changes in interannual variability (based on ratios of predicted to observed standard deviations of annual and seasonal means for 2071-2100 and 1961-1990) were generally less consistent but often tended to decrease with increasing GHG forcing. The data sets will support national and regional climate change impacts studies, including the USDA Forest Service National Renewable Resource Assessment for 2010 and Canadian forest vulnerability assessment for the Canadian Council of Forest Ministers in 2011.

Global warming effects: future feasibility of current cooling equipment for animal houses

NASA Astrophysics Data System (ADS)

Valiño, V.; Perdigones, A.; García, J. L.; de La Plaza, S.

2009-04-01

Interest in global warming effects on the agricultural systems is currently high, especially in areas which are likely to be more affected by this temperature rising, i.e. the Mediterranean area (IPCC, 2008). According to this report, the model projections of surface warming predict a temperature increase between 0.5°C to 1.5°C in the European area by the period 2020-2029. The aim of the present work was to assess the future consequences of the global warming effect on the feasibility of the cooling equipment in animal houses. Several equipment combinations were compared by means of modelling the inside climate in fattening pig houses, including forced ventilation and cooling pad. The modelling was carried out for six different European locations: Spain, Greece, Italy, The Netherlands, Germany and the United Kingdom, for the today conditions; secondly, the global warming effect in the inside climate was considered in a second set of simulations, and a mean temperature rising of 2°C was taken into account. Climate data. The six European locations were: Madrid (Spain); Aliartos (Greece); Bedford (The United Kingdom); Schipol (The Netherlands); Milan (Italy); and Stuttgart (Germany). From every location, the available climate data were monthly mean temperature (To; °C); monthly mean relative humidity (HRo, %) and monthly mean solar irradiation on horizontal surface (So; W m-2). From these monthly values, hourly means were calculated resulting in 24 data for a typical day, each month. Climate model. In this study, cooling strategies resulted from the combination of natural ventilation, mechanical ventilation and cooling pads. The climate model was developed taking into account the following energy fluxes: solar radiation, ventilation (Seginer, 2002), animal heat losses (Blanes and Pedersen, 2005), and loss of energy due to the cooling pads (Seginer, 2002). Results for the present work, show a comparative scene of the inside climate by using different cooling equipment combinations, from natural ventilation to cooling pads. Simulations which include the effects of climate change show the evolution in cooling technologies which will be necessary in this kind of animal houses, in six European locations, if the global temperature rising continues with the current rate. The necessary changes in cooling technologies of animal houses, will be important in Europe when the outside air temperature rising is greater than or equal to two Celsius degrees. Intergovernmental Panel on the Climate Change. 2008. Climate Change 2007: Synthesis Report. http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4syr.pdf I. Seginer. 2002. The Penman-Monteith Evapotranspiration Equation as an Element in Greenhouse Ventilation Design. Biosystems Eng. 82(4): 423-439. doi:10.1006/bioe2002.0086 V. Blanes, S. Pedersen. 2005. Ventilation Flow in Pig Houses measured and calculated by Carbon Dioxide, Moisture and Heat Balance Equations. Biosystems Eng. 92(4): 483-493. doi:10.1006/j.biosystemseng.2005.09.002

Traceable accounts of subjective probability judgments in the IPCC and beyond

NASA Astrophysics Data System (ADS)

Baer, P. G.

2012-12-01

One of the major sources of controversy surrounding the reports of the IPCC has been the characterization of uncertainty. Although arguably the IPCC has paid more attention to the process of uncertainty analysis and communication than any comparable assessment body, its efforts to achieve consistency have produced mixed results. In particular, the extensive use of subjective probability assessment has attracted widespread criticism. Statements such as "Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years" are ubiquitous (one online database lists nearly 3000 such claims), and indeed are the primary way in which its key "findings" are reported. Much attention is drawn to the precise quantitative definition of such statements (e.g., "very likely" means >90% probability, vs. "extremely likely" which means >95% certainty). But there is no process by which the decision regarding the choice of such uncertainty level for a given finding is formally made or reported, and thus they are easily by disputed by anyone, expert or otherwise, who disagrees with the assessment. In the "Uncertainty Guidance Paper" for the Third Assessment Report, Richard Moss and Steve Schneider defined the concept of a "traceable account," which gave exhaustive detail regarding how one ought to provide documentation of such an uncertainty assessment. But the guidance, while appearing straightforward and reasonable, in fact was an unworkable recipe, which would have taken near-infinite time if used for more than a few key results, and would have required a different structuring of the text than the conventional scientific assessment. And even then it would have left a gap when it came to the actual provenance of any such specific judgments, because there simply is no formal step at which individuals turn their knowledge of the evidence on some finding into a probability judgment. The Uncertainty Guidance Papers for the TAR and subsequent assessments have left open the possibility of using such an expert elicitation within the IPCC drafting process, but to my knowledge it has never been done. Were it in fact attempted, it would reveal the inconvenient truth that there is no uniquely correct method for aggregating probability statements; indeed the standard practice within climate-related expert elicitations has been to report all individual estimates without aggregation. But if a report requires a single "consensus estimate," once you have even a single divergent opinion, the question of how to aggregate becomes unavoidable. In this paper, I review in greater detail the match or lack of it between the vision of a "traceable account" and IPCC practice, and the public discussion of selected examples of probabilistic judgments in AR4. I propose elements of a structure based on a flexible software architecture that could facilitate the development and documentation of what I call "collective subjective probability." Using a simple prototype and a pair of sample "findings" from AR4, I demonstrate an example of how such a structure could be used by a small expert community to implement a practical model of a "traceable account." I conclude with as discussion of the prospects of using such modular elicitations in support of, or as an alternative to, conventional IPCC assessment processes.

Climate change unlikely to increase malaria burden in West Africa

NASA Astrophysics Data System (ADS)

Yamana, Teresa K.; Bomblies, Arne; Eltahir, Elfatih A. B.

2016-11-01

The impact of climate change on malaria transmission has been hotly debated. Recent conclusions have been drawn using relatively simple biological models and statistical approaches, with inconsistent predictions. Consequently, the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) echoes this uncertainty, with no clear guidance for the impacts of climate change on malaria transmission, yet recognizing a strong association between local climate and malaria. Here, we present results from a decade-long study involving field observations and a sophisticated model simulating village-scale transmission. We drive the malaria model using select climate models that correctly reproduce historical West African climate, and project reduced malaria burden in a western sub-region and insignificant impact in an eastern sub-region. Projected impacts of climate change on malaria transmission in this region are not of serious concern.

Can we model observed soil carbon changes from a dense inventory? A case study over England and Wales using three versions of the ORCHIDEE ecosystem model (AR5, AR5-PRIM and O-CN)

NASA Astrophysics Data System (ADS)

Guenet, B.; Moyano, F. E.; Vuichard, N.; Kirk, G. J. D.; Bellamy, P. H.; Zaehle, S.; Ciais, P.

2013-12-01

A widespread decrease of the topsoil carbon content was observed over England and Wales during the period 1978-2003 in the National Soil Inventory (NSI), amounting to a carbon loss of 4.44 Tg yr-1 over 141 550 km2. Subsequent modelling studies have shown that changes in temperature and precipitation could only account for a small part of the observed decrease, and therefore that changes in land use and management and resulting changes in heterotrophic respiration or net primary productivity were the main causes. So far, all the models used to reproduce the NSI data have not accounted for plant-soil interactions and have only been soil carbon models with carbon inputs forced by data. Here, we use three different versions of a process-based coupled soil-vegetation model called ORCHIDEE (Organizing Carbon and Hydrology in Dynamic Ecosystems), in order to separate the effect of trends in soil carbon input from soil carbon mineralization induced by climate trends over 1978-2003. The first version of the model (ORCHIDEE-AR5), used for IPCC-AR5 CMIP5 Earth System simulations, is based on three soil carbon pools defined with first-order decomposition kinetics, as in the CENTURY model. The second version (ORCHIDEE-AR5-PRIM) built for this study includes a relationship between litter carbon and decomposition rates, to reproduce a priming effect on decomposition. The last version (O-CN) takes into account N-related processes. Soil carbon decomposition in O-CN is based on CENTURY, but adds N limitations on litter decomposition. We performed regional gridded simulations with these three versions of the ORCHIDEE model over England and Wales. None of the three model versions was able to reproduce the observed NSI soil carbon trend. This suggests either that climate change is not the main driver for observed soil carbon losses or that the ORCHIDEE model even with priming or N effects on decomposition lacks the basic mechanisms to explain soil carbon change in response to climate, which would raise a caution flag about the ability of this type of model to project soil carbon changes in response to future warming. A third possible explanation could be that the NSI measurements made on the topsoil are not representative of the total soil carbon losses integrated over the entire soil depth, and thus cannot be compared with the model output.

Can we model observed soil carbon changes from a dense inventory? A case study over england and wales using three version of orchidee ecosystem model (AR5, AR5-PRIM and O-CN)

NASA Astrophysics Data System (ADS)

Guenet, B.; Moyano, F. E.; Vuichard, N.; Kirk, G. J. D.; Bellamy, P. H.; Zaehle, S.; Ciais, P.

2013-07-01

A widespread decrease of the top soil carbon content was observed over England and Wales during the period 1978-2003 in the National Soil Inventory (NSI), amounting to a carbon loss of 4.44 Tg yr-1 over 141 550 km2. Subsequent modelling studies have shown that changes in temperature and precipitation could only account for a small part of the observed decrease, and therefore that changes in land use and management and resulting changes in soil respiration or primary production were the main causes. So far, all the models used to reproduce the NSI data did not account for plant-soil interactions and were only soil carbon models with carbon inputs forced by data. Here, we use three different versions of a process-based coupled soil-vegetation model called ORCHIDEE, in order to separate the effect of trends in soil carbon input, and soil carbon mineralisation induced by climate trends over 1978-2003. The first version of the model (ORCHIDEE-AR5) used for IPCC-AR5 CMIP5 Earth System simulations, is based on three soil carbon pools defined with first order decomposition kinetics, as in the CENTURY model. The second version (ORCHIDEE-AR5-PRIM) built for this study includes a relationship between litter carbon and decomposition rates, to reproduce a priming effect on decomposition. The last version (O-CN) takes into account N-related processes. Soil carbon decomposition in O-CN is based on CENTURY, but adds N limitations on litter decomposition. We performed regional gridded simulations with these three versions of the ORCHIDEE model over England and Wales. None of the three model versions was able to reproduce the observed NSI soil carbon trend. This suggests that either climate change is not the main driver for observed soil carbon losses, or that the ORCHIDEE model even with priming or N-effects on decomposition lacks the basic mechanisms to explain soil carbon change in response to climate, which would raise a caution flag about the ability of this type of model to project soil carbon changes in response to future warming. A third possible explanation could be that the NSI measurements made on the topsoil are not representative of the total soil carbon losses integrated over the entire soil depth, and thus cannot be compared with the model output.

Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season

PubMed Central

Wallace, John M.; Fu, Qiang; Smoliak, Brian V.; Lin, Pu; Johanson, Celeste M.

2012-01-01

A suite of the historical simulations run with the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) models forced by greenhouse gases, aerosols, stratospheric ozone depletion, and volcanic eruptions and a second suite of simulations forced by increasing CO2 concentrations alone are compared with observations for the reference interval 1965–2000. Surface air temperature trends are disaggregated by boreal cold (November-April) versus warm (May-October) seasons and by high latitude northern (N: 40°–90 °N) versus southern (S: 60 °S–40 °N) domains. A dynamical adjustment is applied to remove the component of the cold-season surface air temperature trends (over land areas poleward of 40 °N) that are attributable to changing atmospheric circulation patterns. The model simulations do not simulate the full extent of the wintertime warming over the high-latitude Northern Hemisphere continents during the later 20th century, much of which was dynamically induced. Expressed as fractions of the concurrent trend in global-mean sea surface temperature, the relative magnitude of the dynamically induced wintertime warming over domain N in the observations, the simulations with multiple forcings, and the runs forced by the buildup of greenhouse gases only is 7∶2∶1, and roughly comparable to the relative magnitude of the concurrent sea-level pressure trends. These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system. Some of the simulations exhibit an enhancement of the warming along the Arctic coast, suggestive of exaggerated feedbacks. PMID:22847408

The Earth System Grid Center for Enabling Technologies (ESG-CET): Scaling the Earth System Grid to Petascale Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Dean N.

2007-09-27

This report, which summarizes work carried out by the ESG-CET during the period April 1, 2007 through September 30, 2007, includes discussion of overall progress, period goals, highlights, collaborations and presentations. To learn more about our project, please visit the Earth System Grid website. In addition, this report will be forwarded to the DOE SciDAC project management, the Office of Biological and Environmental Research (OBER) project management, national and international stakeholders (e.g., the Community Climate System Model (CCSM), the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), the Climate Science Computational End Station (CCES), etc.), and collaborators. Themore » ESG-CET executive committee consists of David Bernholdt, ORNL; Ian Foster, ANL; Don Middleton, NCAR; and Dean Williams, LLNL. The ESG-CET team is a collective of researchers and scientists with diverse domain knowledge, whose home institutions include seven laboratories (ANL, LANL, LBNL, LLNL, NCAR, ORNL, PMEL) and one university (ISI/USC); all work in close collaboration with the project's stakeholders and domain researchers and scientists. During this semi-annual reporting period, the ESG-CET increased its efforts on completing requirement documents, framework design, and component prototyping. As we strove to complete and expand the overall ESG-CET architectural plans and use-case scenarios to fit our constituency's scope of use, we continued to provide production-level services to the community. These services continued for IPCC AR4, CCES, and CCSM, and were extended to include Cloud Feedback Model Intercomparison Project (CFMIP) data.« less

Patterns of authorship in the IPCC Working Group III report

NASA Astrophysics Data System (ADS)

Corbera, Esteve; Calvet-Mir, Laura; Hughes, Hannah; Paterson, Matthew

2016-01-01

The Intergovernmental Panel on Climate Change (IPCC) has completed its Fifth Assessment Report (AR5). Here, we explore the social scientific networks informing Working Group III (WGIII) assessment of mitigation for the AR5. Identifying authors’ institutional pathways, we highlight the persistence and extent of North-South inequalities in the authorship of the report, revealing the dominance of US and UK institutions as training sites for WGIII authors. Examining patterns of co-authorship between WGIII authors, we identify the unevenness in co-authoring relations, with a small number of authors co-writing regularly and indicative of an epistemic community’s influence over the IPCC’s definition of mitigation. These co-authoring networks follow regional patterns, with significant EU-BRICS collaboration and authors from the US relatively insular. From a disciplinary perspective, economists, engineers, physicists and natural scientists remain central to the process, with insignificant participation of scholars from the humanities. The shared training and career paths made apparent through our analysis suggest that the idea that broader geographic participation may lead to a wider range of viewpoints and cultural understandings of climate change mitigation may not be as sound as previously thought.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meehl, G A; Covey, C; McAvaney, B

The Coupled Model Intercomparison Project (CMIP) is designed to allow study and intercomparison of multi-model simulations of present-day and future climate. The latter are represented by idealized forcing of compounded 1% per year CO2 increase to the time of CO2 doubling near year 70 in simulations with global coupled models that contain, typically, components representing atmosphere, ocean, sea ice and land surface. Results from CMIP diagnostic subprojects were presented at the Second CMIP Workshop held at the Max Planck Institute for Meteorology in Hamburg, Germany, in September, 2003. Significant progress in diagnosing and understanding results from global coupled models hasmore » been made since the First CMIP Workshop in Melbourne, Australia in 1998. For example, the issue of flux adjustment is slowly fading as more and more models obtain stable multi-century surface climates without them. El Nino variability, usually about half the observed amplitude in the previous generation of coupled models, is now more accurately simulated in the present generation of global coupled models, though there are still biases in simulating the patterns of maximum variability. Typical resolutions of atmospheric component models contained in coupled models is now usually around 2.5 degrees latitude-longitude, with the ocean components often having about twice the atmospheric model resolution, with even higher resolution in the equatorial tropics. Some new-generation coupled models have atmospheric model resolutions of around 1.5 degrees latitude-longitude. Modeling groups now routinely run the CMIP control and 1% CO2 simulations in addition to 20th and 21st century climate simulations with a variety of forcings (e.g. volcanoes, solar variability, anthropogenic sulfate aerosols, ozone, and greenhouse gases (GHGs), with the anthropogenic forcings for future climate as well). However, persistent systematic errors noted in previous generations of global coupled models still are present in the present generation (e.g. over-extensive equatorial Pacific cold tongue, double ITCZ). This points to the next challenge for the global coupled climate modeling community. Planning and imminent commencement of the IPCC Fourth Assessment Report (AR4) has prompted rapid coupled model development, which will lead to an expanded CMIP-like activity to collect and analyze results for the control, 1% CO2, 20th, 21st and 22nd century simulations performed for the AR4. The international climate community is encouraged to become involved in this analysis effort, and details are provided below in how to do so.« less

Model for estimating enteric methane emissions from United States dairy and feedlot cattle.

PubMed

Kebreab, E; Johnson, K A; Archibeque, S L; Pape, D; Wirth, T

2008-10-01

Methane production from enteric fermentation in cattle is one of the major sources of anthropogenic greenhouse gas emission in the United States and worldwide. National estimates of methane emissions rely on mathematical models such as the one recommended by the Intergovernmental Panel for Climate Change (IPCC). Models used for prediction of methane emissions from cattle range from empirical to mechanistic with varying input requirements. Two empirical and 2 mechanistic models (COWPOLL and MOLLY) were evaluated for their prediction ability using individual cattle measurements. Model selection was based on mean square prediction error (MSPE), concordance correlation coefficient, and residuals vs. predicted values analyses. In dairy cattle, COWPOLL had the lowest root MSPE and greatest accuracy and precision of predicting methane emissions (correlation coefficient estimate = 0.75). The model simulated differences in diet more accurately than the other models, and the residuals vs. predicted value analysis showed no mean bias (P = 0.71). In feedlot cattle, MOLLY had the lowest root MSPE with almost all errors from random sources (correlation coefficient estimate = 0.69). The IPCC model also had good agreement with observed values, and no significant mean (P = 0.74) or linear bias (P = 0.11) was detected when residuals were plotted against predicted values. A fixed methane conversion factor (Ym) might be an easier alternative to diet-dependent variable Ym. Based on the results, the 2 mechanistic models were used to simulate methane emissions from representative US diets and were compared with the IPCC model. The average Ym in dairy cows was 5.63% of GE (range 3.78 to 7.43%) compared with 6.5% +/- 1% recommended by IPCC. In feedlot cattle, the average Ym was 3.88% (range 3.36 to 4.56%) compared with 3% +/- 1% recommended by IPCC. Based on our simulations, using IPCC values can result in an overestimate of about 12.5% and underestimate of emissions by about 9.8% for dairy and feedlot cattle, respectively. In addition to providing improved estimates of emissions based on diets, mechanistic models can be used to assess mitigation options such as changing source of carbohydrate or addition of fat to decrease methane, which is not possible with empirical models. We recommend national inventories use diet-specific Ym values predicted by mechanistic models to estimate methane emissions from cattle.

The Impact of Climate Change in Rainfall Erosivity Index on Humid Mudstone Area

NASA Astrophysics Data System (ADS)

Yang, Ci-Jian; Lin, Jiun-Chuan

2017-04-01

It has been quite often pointed out in many relevant studies that climate change may result in negative impacts on soil erosion. Then, humid mudstone area is highly susceptible to climate change. Taiwan has extreme erosion in badland area, with annual precipitation over 2000 mm/y which is a considerably 3 times higher than other badland areas around the world, and with around 9-13 cm/y in denudation rate. This is the reason why the Erren River, a badland dominated basin has the highest mean sediment yield in the world, over 105 t km2 y. This study aims to know how the climate change would affect soil erosion from the source in the Erren River catchment. Firstly, the data of hourly precipitation from 1992 to 2016 are used to establish the regression between rainfall erosivity index (R, one of component for USLE) and precipitation. Secondly, using the 10 climate change models (provide form IPCC AR5) simulates the changes of monthly precipitation in different scenario from 2017 to 2216, and then over 200 years prediction R values can be use to describe the tendency of soil erosion in the future. The results show that (1) the relationship between rainfall erosion index and precipitation has high correction (>0.85) during 1992-2016. (2) From 2017 to 2216, 7 scenarios show that annual rainfall erosion index will increase over 2-18%. In contrast, the others will decrease over 7-14%. Overall, the variations of annual rainfall erosion index fall in the range of -14 to 18%, but it is important to pay attention to the variation of annual rainfall erosion index in extreme years. These fall in the range of -34 to 239%. This explains the extremity of soil erosion will occur easily in the future. Keywords: Climate Change, Mudstone, Rainfall Erosivity Index, IPCC AR5

Towards the Prediction of Decadal to Centennial Climate Processes in the Coupled Earth System Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhengyu; Kutzbach, J.; Jacob, R.

2011-12-05

In this proposal, we have made major advances in the understanding of decadal and long term climate variability. (a) We performed a systematic study of multidecadal climate variability in FOAM-LPJ and CCSM-T31, and are starting exploring decadal variability in the IPCC AR4 models. (b) We develop several novel methods for the assessment of climate feedbacks in the observation. (c) We also developed a new initialization scheme DAI (Dynamical Analogue Initialization) for ensemble decadal prediction. (d) We also studied climate-vegetation feedback in the observation and models. (e) Finally, we started a pilot program using Ensemble Kalman Filter in CGCM for decadalmore » climate prediction.« less

Enhanced future variability during India's rainy season

NASA Astrophysics Data System (ADS)

Menon, Arathy; Levermann, Anders; Schewe, Jacob

2013-04-01

The Indian summer monsoon shapes the livelihood of a large share of the world's population. About 80% of annual precipitation over India occurs during the monsoon season from June through September. Next to its seasonal mean rainfall the day-to-day variability is crucial for the risk of flooding, national water supply and agricultural productivity. Here we show that the latest ensemble of climate model simulations, prepared for the IPCC's AR-5, consistently projects significant increases in day-to-day rainfall variability under unmitigated climate change. While all models show an increase in day-to-day variability, some models are more realistic in capturing the observed seasonal mean rainfall over India than others. While no model's monsoon rainfall exceeds the observed value by more than two standard deviations, half of the models simulate a significantly weaker monsoon than observed. The relative increase in day-to-day variability by the year 2100 ranges from 15% to 48% under the strongest scenario (RCP-8.5), in the ten models which capture seasonal mean rainfall closest to observations. The variability increase per degree of global warming is independent of the scenario in most models, and is 8% +/- 4% per K on average. This consistent projection across 20 comprehensive climate models provides confidence in the results and suggests the necessity of profound adaptation measures in the case of unmitigated climate change.

Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

NASA Astrophysics Data System (ADS)

Fan, Tianyi; Liu, Xiaohong; Ma, Po-Lun; Zhang, Qiang; Li, Zhanqing; Jiang, Yiquan; Zhang, Fang; Zhao, Chuanfeng; Yang, Xin; Wu, Fang; Wang, Yuying

2018-02-01

Global climate models often underestimate aerosol loadings in China, and these biases can have significant implications for anthropogenic aerosol radiative forcing and climate effects. The biases may be caused by either the emission inventory or the treatment of aerosol processes in the models, or both, but so far no consensus has been reached. In this study, a relatively new emission inventory based on energy statistics and technology, Multi-resolution Emission Inventory for China (MEIC), is used to drive the Community Atmosphere Model version 5 (CAM5) to evaluate aerosol distribution and radiative effects against observations in China. The model results are compared with the model simulations with the widely used Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) emission inventory. We find that the new MEIC emission improves the aerosol optical depth (AOD) simulations in eastern China and explains 22-28 % of the AOD low bias simulated with the AR5 emission. However, AOD is still biased low in eastern China. Seasonal variation of the MEIC emission leads to a better agreement with the observed seasonal variation of primary aerosols than the AR5 emission, but the concentrations are still underestimated. This implies that the atmospheric loadings of primary aerosols are closely related to the emission, which may still be underestimated over eastern China. In contrast, the seasonal variations of secondary aerosols depend more on aerosol processes (e.g., gas- and aqueous-phase production from precursor gases) that are associated with meteorological conditions and to a lesser extent on the emission. It indicates that the emissions of precursor gases for the secondary aerosols alone cannot explain the low bias in the model. Aerosol secondary production processes in CAM5 should also be revisited. The simulation using MEIC estimates the annual-average aerosol direct radiative effects (ADREs) at the top of the atmosphere (TOA), at the surface, and in the atmosphere to be -5.02, -18.47, and 13.45 W m-2, respectively, over eastern China, which are enhanced by -0.91, -3.48, and 2.57 W m-2 compared with the AR5 emission. The differences of ADREs by using MEIC and AR5 emissions are larger than the decadal changes of the modeled ADREs, indicating the uncertainty of the emission inventories. This study highlights the importance of improving both the emission and aerosol secondary production processes in modeling the atmospheric aerosols and their radiative effects. Yet, if the estimations of MEIC emissions in trace gases do not suffer similar biases to those in the AOD, our findings will help affirm a fundamental error in the conversion from precursor gases to secondary aerosols as hinted in other recent studies following different approaches.

Global Mean Temperature Timeseries Projections from GCMs: The Implications of Rebasing

NASA Astrophysics Data System (ADS)

Chapman, S. C.; Stainforth, D. A.; Watkins, N. W.

2017-12-01

Global climate models are assessed by comparison with observations through several benchmarks. One highlighted by the InterGovernmental Panel on Climate Change (IPCC) is their ability to reproduce "general features of the global and annual mean surface temperature changes over the historical period" [1,2] and to simulate "a trend in global-mean surface temperature from 1951 to 2012 that agrees with the observed trend" [3]. These aspects of annual mean global mean temperature (GMT) change are presented as one feature demonstrating the relevance of these models for climate projections. Here we consider a formal interpretation of "general features" and discuss the implications of this approach to model assessment and intercomparison, for the interpretation of GCM projections. Following the IPCC, we interpret a major element of "general features" as being the slow timescale response to external forcings. (Shorter timescale behaviour such as the response to volcanic eruptions are also elements of "general features" but are not considered here.) Also following the IPCC, we consider only GMT anomalies. The models have absolute temperatures which range over about 3K so this means their timeseries (and the observations) are rebased. We show that rebasing in combination with general agreement, implies a separation of scales which limits the degree to which sub-global behaviour can feedback on the global response. It also implies a degree of linearity in the GMT slow timescale response. For each individual model these implications only apply over the range of absolute temperatures simulated by the model in historic simulations. Taken together, however, they imply consequences over a wider range of GMTs. [1] IPCC, Fifth Assessment Report, Working Group 1, Technical Summary: Stocker et al. 2013. [2] IPCC, Fifth Assessment Report, Working Group 1, Chapter 9 - "Evaluation of Climate Models": Flato et al. 2013. [3] IPCC, Fifth Assessment Report, Working Group 1, Summary for Policy Makers: IPCC, 2013.

Assessment of surface air temperature over the Arctic Ocean in reanalysis and IPCC AR4 model simulations with IABP/POLES observations

NASA Astrophysics Data System (ADS)

Liu, Jiping; Zhang, Zhanhai; Hu, Yongyun; Chen, Liqi; Dai, Yongjiu; Ren, Xiaobo

2008-05-01

The surface air temperature (SAT) over the Arctic Ocean in reanalyses and global climate model simulations was assessed using the International Arctic Buoy Programme/Polar Exchange at the Sea Surface (IABP/POLES) observations for the period 1979-1999. The reanalyses, including the National Centers for Environmental Prediction Reanalysis II (NCEP2) and European Centre for Medium-Range Weather Forecast 40-year Reanalysis (ERA40), show encouraging agreement with the IABP/POLES observations, although some spatiotemporal discrepancies are noteworthy. The reanalyses have warm annual mean biases and underestimate the observed interannual SAT variability in summer. Additionally, NCEP2 shows an excessive warming trend. Most model simulations (coordinated by the International Panel on Climate Change for its Fourth Assessment Report) reproduce the annual mean, seasonal cycle, and trend of the observed SAT reasonably well, particularly the multi-model ensemble mean. However, large discrepancies are found. Some models have the annual mean SAT biases far exceeding the standard deviation of the observed interannul SAT variability and the across-model standard deviation. Spatially, the largest inter-model variance of the annual mean SAT is found over the North Pole, Greenland Sea, Barents Sea and Baffin Bay. Seasonally, a large spread of the simulated SAT among the models is found in winter. The models show interannual variability and decadal trend of various amplitudes, and can not capture the observed dominant SAT mode variability and cooling trend in winter. Further discussions of the possible attributions to the identified SAT errors for some models suggest that the model's performance in the sea ice simulation is an important factor.

The Change of First-flowering Date over South Korea Projected from Downscaled IPCC AR5 Simulation: Peach and Pear

NASA Astrophysics Data System (ADS)

Ahn, J. B.; Hur, J.

2014-12-01

The variations in the first-flowering date (FFD) of peach (Prunus persica) and pear (Pyrus pyrifolia) under future climate change in South Korea are investigated using simulations obtained from five models of the fifth Coupled Model Intercomparison Project. For the study, daily temperature simulations with Historical (1986-2005), and RCP (2071-2090) 4.5 and 8.5 scenarios are statistically downscaled to 50 peach and pear FFD (FFDpeach and FFDpear, respectively) observation sites over South Korea. The number of days transformed to standard temperature (DTS) method is selected as the phenological model and applied to simulations for estimating FFDpeach and FFDpear over South Korea, due to its superior performance on the target plants and region compared to the growing degree days (GDD) and chill days (CD) methods. In the analysis, mean temperatures for early spring (February to April) over South Korea in 2090 under RCP4.5 and 8.5 scenarios are expected to have increased by 1.9K and 3.3K, respectively. Among the early spring months of February to April, February shows the largest temperature increase of 2.1K and 3.7K for RCP4.5 and 8.5 scenarios, respectively. The increased temperature during February and March accelerates the plant growth rate and thereby advances FFDpeach by 7.0 and 12.7 days and FFDpear by 6.1 and 10.7 days, respectively. These results imply that the present flowering of peach and pear in the middle of April will have advanced to late March or early April by the end of this century. Acknowledgements This work was carried out with the support of the Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009953, Republic of Korea.

Enhanced mesoscale climate projections in TAR and AR5 IPCC scenarios: a case study in a Mediterranean climate (Araucanía Region, south central Chile).

PubMed

Orrego, R; Abarca-Del-Río, R; Ávila, A; Morales, L

2016-01-01

Climate change scenarios are computed on a large scale, not accounting for local variations presented in historical data and related to human scale. Based on historical records, we validate a baseline (1962-1990) and correct the bias of A2 and B2 regional projections for the end of twenty-first century (2070-2100) issued from a high resolution dynamical downscaled (using PRECIS mesoscale model, hereinafter DGF-PRECIS) of Hadley GCM from the IPCC 3rd Assessment Report (TAR). This is performed for the Araucanía Region (Chile; 37°-40°S and 71°-74°W) using two different bias correction methodologies. Next, we study high-resolution precipitations to find monthly patterns such as seasonal variations, rainfall months, and the geographical effect on these two scenarios. Finally, we compare the TAR projections with those from the recent Assessment Report 5 (AR5) to find regional precipitation patterns and update the Chilean `projection. To show the effects of climate change projections, we compute the rainfall climatology for the Araucanía Region, including the impact of ENSO cycles (El Niño and La Niña events). The corrected climate projection from the high-resolution dynamical downscaled model of the TAR database (DGF-PRECIS) show annual precipitation decreases: B2 (-19.19 %, -287 ± 42 mm) and A2 (-43.38 %, -655 ± 27.4 mm per year. Furthermore, both projections increase the probability of lower rainfall months (lower than 100 mm per month) to 64.2 and 72.5 % for B2 and A2, respectively.

Enhanced mesoscale climate projections in TAR and AR5 IPCC scenarios: a case study in a Mediterranean climate (Araucanía Region, south central Chile)

DOE PAGES

Orrego, R.; Abarca-del-Rio, R.; Avila, A.; ...

2016-09-28

Here, climate change scenarios are computed on a large scale, not accounting for local variations presented in historical data and related to human scale. Based on historical records, we validate a baseline (1962–1990) and correct the bias of A2 and B2 regional projections for the end of twenty-first century (2070–2100) issued from a high resolution dynamical downscaled (using PRECIS mesoscale model, hereinafter DGF-PRECIS) of Hadley GCM from the IPCC 3rd Assessment Report (TAR). This is performed for the Araucanía Region (Chile; 37°–40°S and 71°–74°W) using two different bias correction methodologies. Next, we study high-resolution precipitations to find monthly patterns suchmore » as seasonal variations, rainfall months, and the geographical effect on these two scenarios. Finally, we compare the TAR projections with those from the recent Assessment Report 5 (AR5) to find regional precipitation patterns and update the Chilean `projection. To show the effects of climate change projections, we compute the rainfall climatology for the Araucanía Region, including the impact of ENSO cycles (El Niño and La Niña events). The corrected climate projection from the high-resolution dynamical downscaled model of the TAR database (DGF-PRECIS) show annual precipitation decreases: B2 (-19.19 %, -287 ± 42 mm) and A2 (-43.38 %, -655 ± 27.4 mm per year. Furthermore, both projections increase the probability of lower rainfall months (lower than 100 mm per month) to 64.2 and 72.5 % for B2 and A2, respectively.« less

Enhanced mesoscale climate projections in TAR and AR5 IPCC scenarios: a case study in a Mediterranean climate (Araucanía Region, south central Chile)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrego, R.; Abarca-del-Rio, R.; Avila, A.

Here, climate change scenarios are computed on a large scale, not accounting for local variations presented in historical data and related to human scale. Based on historical records, we validate a baseline (1962–1990) and correct the bias of A2 and B2 regional projections for the end of twenty-first century (2070–2100) issued from a high resolution dynamical downscaled (using PRECIS mesoscale model, hereinafter DGF-PRECIS) of Hadley GCM from the IPCC 3rd Assessment Report (TAR). This is performed for the Araucanía Region (Chile; 37°–40°S and 71°–74°W) using two different bias correction methodologies. Next, we study high-resolution precipitations to find monthly patterns suchmore » as seasonal variations, rainfall months, and the geographical effect on these two scenarios. Finally, we compare the TAR projections with those from the recent Assessment Report 5 (AR5) to find regional precipitation patterns and update the Chilean `projection. To show the effects of climate change projections, we compute the rainfall climatology for the Araucanía Region, including the impact of ENSO cycles (El Niño and La Niña events). The corrected climate projection from the high-resolution dynamical downscaled model of the TAR database (DGF-PRECIS) show annual precipitation decreases: B2 (-19.19 %, -287 ± 42 mm) and A2 (-43.38 %, -655 ± 27.4 mm per year. Furthermore, both projections increase the probability of lower rainfall months (lower than 100 mm per month) to 64.2 and 72.5 % for B2 and A2, respectively.« less

Augmented versus Virtual Reality Laparoscopic Simulation: What Is the Difference?

PubMed Central

Botden, Sanne M.B.I.; Buzink, Sonja N.; Schijven, Marlies P.

2007-01-01

Background Virtual reality (VR) is an emerging new modality for laparoscopic skills training; however, most simulators lack realistic haptic feedback. Augmented reality (AR) is a new laparoscopic simulation system offering a combination of physical objects and VR simulation. Laparoscopic instruments are used within an hybrid mannequin on tissue or objects while using video tracking. This study was designed to assess the difference in realism, haptic feedback, and didactic value between AR and VR laparoscopic simulation. Methods The ProMIS AR and LapSim VR simulators were used in this study. The participants performed a basic skills task and a suturing task on both simulators, after which they filled out a questionnaire about their demographics and their opinion of both simulators scored on a 5-point Likert scale. The participants were allotted to 3 groups depending on their experience: experts, intermediates and novices. Significant differences were calculated with the paired t-test. Results There was general consensus in all groups that the ProMIS AR laparoscopic simulator is more realistic than the LapSim VR laparoscopic simulator in both the basic skills task (mean 4.22 resp. 2.18, P < 0.000) as well as the suturing task (mean 4.15 resp. 1.85, P < 0.000). The ProMIS is regarded as having better haptic feedback (mean 3.92 resp. 1.92, P < 0.000) and as being more useful for training surgical residents (mean 4.51 resp. 2.94, P < 0.000). Conclusions In comparison with the VR simulator, the AR laparoscopic simulator was regarded by all participants as a better simulator for laparoscopic skills training on all tested features. PMID:17361356

PM2.5 and tropospheric ozone in China: overview of situation and responses

NASA Astrophysics Data System (ADS)

Zhang, Hua

This work reviewed the observational status of PM2.5 and tropospheric ozone in China. It told us the observational facts on the ratios of typical types of aerosol components to the total PM2.5/PM10, and daily and seasonal change of near surface ozone concentration at different cities of China; the global concentration distribution of tropospheric ozone observed by satellite in 2010-2013 was also given for comparison; the PM2.5 concentration distribution and their seasonal change in China region were simulated by an aerosol chemistry-global climate modeling system. Different contribution from five kinds of aerosols to the simulated PM2.5 was analyzed. Then, it linked the emissions of aerosol and greenhouse gases and their radiative forcing and thus gave their climatic effect by reducing their emissions on the basis of most recently published IPCC AR5. Finally it suggested policies on reducing emissions of short-lived climate pollutants (SLCPs) (such as PM2.5 and tropospheric ozone) in China from protecting both climate and environment.

Assessing modelled spatial distributions of ice water path using satellite data

NASA Astrophysics Data System (ADS)

Eliasson, S.; Buehler, S. A.; Milz, M.; Eriksson, P.; John, V. O.

2010-05-01

The climate models used in the IPCC AR4 show large differences in monthly mean cloud ice. The most valuable source of information that can be used to potentially constrain the models is global satellite data. For this, the data sets must be long enough to capture the inter-annual variability of Ice Water Path (IWP). PATMOS-x was used together with ISCCP for the annual cycle evaluation in Fig. 7 while ECHAM-5 was used for the correlation with other models in Table 3. A clear distinction between ice categories in satellite retrievals, as desired from a model point of view, is currently impossible. However, long-term satellite data sets may still be used to indicate the climatology of IWP spatial distribution. We evaluated satellite data sets from CloudSat, PATMOS-x, ISCCP, MODIS and MSPPS in terms of monthly mean IWP, to determine which data sets can be used to evaluate the climate models. IWP data from CloudSat cloud profiling radar provides the most advanced data set on clouds. As CloudSat data are too short to evaluate the model data directly, it was mainly used here to evaluate IWP from the other satellite data sets. ISCCP and MSPPS were shown to have comparatively low IWP values. ISCCP shows particularly low values in the tropics, while MSPPS has particularly low values outside the tropics. MODIS and PATMOS-x were in closest agreement with CloudSat in terms of magnitude and spatial distribution, with MODIS being the best of the two. As PATMOS-x extends over more than 25 years and is in fairly close agreement with CloudSat, it was chosen as the reference data set for the model evaluation. In general there are large discrepancies between the individual climate models, and all of the models show problems in reproducing the observed spatial distribution of cloud-ice. Comparisons consistently showed that ECHAM-5 is the GCM from IPCC AR4 closest to satellite observations.

Preoptimised VB: a fast method for the ground and excited states of ionic clusters I. Localised preoptimisation for (ArCO) +, (ArN 2) + and N 4+

NASA Astrophysics Data System (ADS)

Langenberg, J. H.; Bucur, I. B.; Archirel, P.

1997-09-01

We show that in the simple case of van der Waals ionic clusters, the optimisation of orbitals within VB can be easily simulated with the help of pseudopotentials. The procedure yields the ground and the first excited states of the cluster simultaneously. This makes the calculation of potential energy surfaces for tri- and tetraatomic clusters possible, with very acceptable computation times. We give potential curves for (ArCO) +, (ArN 2) + and N 4+. An application to the simulation of the SCF method is shown for Na +H 2O.

Harmonisation of Global Land-Use Scenarios for the Period 1500-2100 for IPCC-AR5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurtt, George; Chini, Louise Parsons; Frolking, Steve

2009-06-01

In preparation for the fifth Intergovernmental Panel on Climate Change climate change assessment (IPCC-AR5), the international community is developing new advanced computer models (CMs) to address the combined effects of human activities (e.g. land-use and fossil fuel emissions) on the carbon-climate system. In addition, four Representative Concentration Pathway (RCP) scenarios of the future (2005-2100) are being developed by four Integrated Assessment Modeling teams (IAMs) to be used as input to the CMs for future climate projections. The diversity of requirements and approaches among CMs and IAMs for tracking land-use changes (past, present, and future), presents major challenges for treating land-usemore » comprehensively and consistently between these communities. As part of an international working group, we have been working to meet these challenges by developing a "harmonized" set of land-use change scenarios that smoothly connects gridded historical reconstructions of land-use with future projections, in a format required by CMs. This approach to harmonizing the treatment of land-use between two key modeling communities, CMs and IAMs, represents a major advance that will facilitate more consistent and fuller treatments of land-use/land-use change effects including both CO2 emissions and corresponding land-surface changes.« less

Working Gas Selection of the Honeycomb Converter-Based Neutron Detector

NASA Astrophysics Data System (ADS)

Fang, Zhujun; Yang, Yigang; Li, Yulan; Wang, Xuewu

2017-07-01

To reduce the manufacturing difficulty and improve the robustness of traditional boron-lined detectors that may replace the 3He counter, the honeycomb neutron converter-based gaseous neutron detector has been proposed. A drift electric field is applied to drive electrons ionized by α or 7Li after the 10B(n, α)7Li reaction from their origination positions to the incident surface of the gas electron multiplier (GEM), which multiplies electrons and forms the neutron signal. As the working gas affects the energy deposition of α or 7Li, the transverse diffusion of electrons in the migration process, as well as the multiplication of electrons in the GEM detector, the working gas selection of the honeycomb converter-based detector would be very important. Fourteen different working gases are investigated in detail through simulation research. Four working gases, Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, Ar:CH4 = 90:10, and Ar:DME = 95:5, are experimentally tested. Both the simulation and experimental results demonstrate that working gases of Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, and Ar:DME = 95:5 show good performances benefitting from both the large stopping powers of α or 7Li and the small transverse diffusion coefficients of electrons. The simulation results indicate that the detection efficiency with one of the three gases is 1.33 to 1.48 times the Ar:CH4 = 90:10, while the experimental results demonstrate that there is 1.34-1.49 times of the detection efficiency. The research in this paper helps improve the performance of the honeycomb converter-based neutron detector.

Methane emissions associated with the conversion of marshland to cropland and climate change on the Sanjiang Plain of Northeast China from 1950 to 2100

NASA Astrophysics Data System (ADS)

Li, T.; Huang, Y.; Zhang, W.; Yu, Y. Q.

2012-05-01

Wetland loss and climate change are known to alter regional and global methane (CH4) budgets. Over the last six decades, an extensive area of marshland has been converted to cropland on the Sanjiang Plain in Northeast China, and a significant increase in air temperature has also been observed there, while the impacts on regional CH4 budgets remain uncertain. Through model simulation, we estimated the changes in CH4 emissions associated with the conversion of marshland to cropland and climate change in this area. Model simulations indicated a significant reduction of 1.1 Tg yr-1 from the 1950s to the 2000s in regional CH4 emissions. The cumulative reduction of CH4 from 1960 to 2009 was estimated to be ~36 Tg relative to the 1950s, and marshland conversion and the climate contributed 86 % and 14 % of this change, respectively. Interannual variation in precipitation (linear trend with P > 0.2) contributed to yearly fluctuations in CH4 emissions, but the relatively lower amount of precipitation over the period 1960-2009 (47 mm yr-1 lower on average than in the 1950s) contributed ~91 % of the reduction in the area-weighted CH4 flux. Global warming at a rate of 0.3 °C per decade (P < 0.001) has increased CH4 emissions significantly since the 1990s. Relative to the mean of the 1950s, the warming-induced increase in the CH4 flux has averaged 19 kg ha-1 yr-1 over the last two decades. For the RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 scenarios of the fifth IPCC assessment report (AR5), the CH4 flux is predicted to increase by 36 %, 52 %, 78 % and 95 %, respectively, by the 2080s compared to 1961-1990 in response to climate warming and wetting.

Decadal Recruitment and Mortality of Ponderosa pine Predicted for the 21st Century Under five Downscaled Climate Change Scenarios

NASA Astrophysics Data System (ADS)

Ironside, K. E.; Cole, K. L.; Eischeid, J. K.; Garfin, G. M.; Shaw, J. D.; Cobb, N. S.

2008-12-01

Ponderosa pine (Pinus ponderosa var. scopulorum) is the dominant conifer in higher elevation regions of the southwestern United States. Because this species is so prominent, southwestern montane ecosystems will be significantly altered if this species is strongly affected by future climate changes. These changes could be highly challenging for land management agencies. In order to model the consequences of future climates, 20th Century recruitment events and mortality for ponderosa pine were characterized using measures of seasonal water balance (precipitation - potential evapotranspiration). These relationships, assuming they will remain unchanged, were then used to predict 21st Century changes in ponderosa pine occurrence in the southwest. Twenty-one AR4 IPCC General Circulation Model (GCM) A1B simulation results were ranked on their ability to simulate the later 20th Century (1950-2000 AD) precipitation seasonality, spatial patterns, and quantity in the western United States. Among the top ranked GCMs, five were selected for downscaling to a 4 km grid that represented a range in predictions in terms of changes in water balance. Predicted decadal changes in southwestern ponderosa pine for the 21st Century for these five climate change scenarios were calculated using a multiple quadratic logistic regression model. Similar models of other western tree species (Pinus edulis, Yucca brevifolia) predicted severe contractions, especially in the southern half of their ranges. However, the results for Ponderosa pine suggested future expansions throughout its range to both higher and lower elevations, as well as very significant expansions northward.

Measuring Engagement with the Potential Consequences of Climate Change

NASA Astrophysics Data System (ADS)

Young, N.; Danielson, R. W.; Lombardi, D.

2015-12-01

Across three studies, we investigated engagement with the consequences of climate change. We drew from the conceptual change and risk analysis literatures to find the factors that determine how much people will care about future risks. Questions derived from these factors were then asked about many hypothesized consequences of climate change. These consequences were drawn from an Intergovernmental Panel on Climate Change special report (IPCC, 2012) and, in the third study, additionally from the IPCC AR5 (IPCC, 2014). The first two studies, using undergraduate students, demonstrated that some consequences were indeed considerably more engaging than others. The third study used a more representative sample of American adults, drawn from Amazon Mechanical Turk and used the Global Warming's Six Americas Screening Tool (Maibach, Leiserowitz, Roser-Renouf, Mertz, & Akerlof, 2011) in a large screening survey to find 20 participants in each of the six audiences defined by this tool. These participants were then asked about the potential consequences of climate change. Results again showed that some consequences are considered more engaging than others, and also showed the ways in which members of these six audiences perceive the consequences of climate change differently.

Emergence of the significant local warming of Korea in CMIP5 projections

NASA Astrophysics Data System (ADS)

Boo, Kyung-On; Shim, Sungbo; Kim, Jee-Eun

2016-04-01

According to IPCC AR5, anthropogenic influence on warming is obvious in local scales, especially in some tropical regions. Detection of significant local warming is important for adaptation to climate change of society and ecosystem. Recently much attention has focused on the time of emergence (ToE) for the signal of anthropogenic climate change against the natural climate variability. Motivated from the previous studies, this study analyzes ToE of regional surface air temperature over Korea. Simulations of CMIP5 15 models are used for RCP 2.6, 4.5 and 8.5. For each year, JJA and DJF temperature anomalies are calculated for the time period 1900-1929. For noise of interannual variability, natural-only historical simulations of CMIP5 12 models are used and the standard deviation of the time series is obtained. For signal of warming, we examine the year when the signal above 2 standard deviations is detected in 80% of the models using 30-year smoothed time series. According to our results, interannual variability is larger in land than ocean. Seasonally, it is larger in winter than in summer. Accordingly, ToE of summertime temperature is earlier than that in winter and is expected to appear in 2030s from three RCPs. The seasonal difference is consistent with previous studies. Wintertime ToE appears in 2040s for RCP85 and 2060s for RCP4.5. The different emergence time between RCP8.5 and RCP4.5 reflects the influence of mitigation. In a similar way, daily maximum and minimum temperatures are analyzed. ToE of Tmin appears earlier than that of Tmax and difference is small. Acknowledgements. This study is supported by the National Institute of Meteorological Sciences, Korea Meteorological Administration (NIMR-2012-B-2).

From land use to land cover: Restoring the afforestation signal in a coupled integrated assessment - earth system model and the implications for CMIP5 RCP simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Vittorio, Alan V.; Chini, Louise M.; Bond-Lamberty, Benjamin

2014-11-27

Climate projections depend on scenarios of fossil fuel emissions and land use change, and the IPCC AR5 parallel process assumes consistent climate scenarios across Integrated Assessment and Earth System Models (IAMs and ESMs). To facilitate consistency, CMIP5 used a novel land use harmonization to provide ESMs with seamless, 1500-2100 land use trajectories generated by historical data and four IAMs. However, we have identified and partially addressed a major gap in the CMIP5 land coupling design. The CMIP5 Community ESM (CESM) global afforestation is only 22% of RCP4.5 afforestation from 2005 to 2100. Likewise, only 17% of the Global Change Assessmentmore » Model’s (GCAM’s) 2040 RCP4.5 afforestation signal, and none of the pasture loss, were transmitted to CESM within a newly integrated model. This is a critical problem because afforestation is necessary for achieving the RCP4.5 climate stabilization. We attempted to rectify this problem by modifying only the ESM component of the integrated model, enabling CESM to simulate 66% of GCAM’s afforestation in 2040, and 94% of GCAM’s pasture loss as grassland and shrubland losses. This additional afforestation increases vegetation carbon gain by 19 PgC and decreases atmospheric CO2 gain by 8 ppmv from 2005 to 2040, implying different climate scenarios between CMIP5 GCAM and CESM. Similar inconsistencies likely exist in other CMIP5 model results, primarily because land cover information is not shared between models, with possible contributions from afforestation exceeding model-specific, potentially viable forest area. Further work to harmonize land cover among models will be required to adequately rectify this problem.« less

An Assessment of IPCC 20th Century Climate Simulations Using the 15-year Sea Level Record from Altimetry

NASA Astrophysics Data System (ADS)

Leuliette, E.; Nerem, S.; Jakub, T.

2006-07-01

Recen tly, multiple ensemble climate simulations h ave been produced for th e forthco ming Fourth A ssessment Report of the Intergovernmental Panel on Climate Change (IPCC). N early two dozen coupled ocean- atmo sphere models have contr ibuted output for a variety of climate scen arios. One scenar io, the climate of the 20th century exper imen t (20C3 M), produces model output that can be comp ared to th e long record of sea level provided by altimetry . Generally , the output from the 20C3M runs is used to initialize simulations of future climate scenar ios. Hence, v alidation of the 20 C3 M experiment resu lts is crucial to the goals of th e IPCC. We present compar isons of global mean sea level (G MSL) , global mean steric sea level change, and regional patterns of sea lev el chang e from these models to r esults from altimetry, tide gauge measurements, and reconstructions.

Towards the IPCC Special Report on Global Warming of 1.5°C

NASA Astrophysics Data System (ADS)

Masson-Delmotte, Valérie

2017-04-01

The Intergovernemental Panel on Climate Change (IPCC) has accepted the invitation from the Paris Agreement to prepare a special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. This special report is prepared under the scientific leadership of the co-chairs of the IPCC Working Groups I, II and III, and with operational support from the Technical Support Unit of Working Group I. It will consist of 5 chapters, providing (i) framing and context, (ii) exploring mitigation pathways compatible with 1.5°C in the context of sustainable development, (iii) assessing impacts of 1.5°C global warming on natural and human systems, and (iv) options for strengthening and implementing the global response to the threat of climate change, with a final chapter on sustainable development, poverty eradication and reducing inequalities. The timeline of preparation of the report is extremely short, with four lead author meetings taking place from March 2017 to April 2018, and an approval session scheduled in September 2018. It is crucial that new knowledge is being produced and submitted / published in the literature in time for contributing new material to be assessed by the authors of the report (with deadlines in late fall 2017 and spring 2018). With respect to the additional impacts expected for 1.5°C warming compared to present-day, and impacts avoided with respect to larger warming, new research is expected to build on existing CMIP5 projections, including new information on regional change, methods to provide knowledge for the most vulnerable ecosystems and regions, but also information from ongoing projects aiming to produce large ensembles of simulations, and new simulations driven by low carbon pathways. This is important for identifying climate change signals from climate variability (e.g. changes in water cycle, extremes...), for assessing strengths and limitations of methodologies using high end climate scenarios versus true stabilisation pathways, and for exploring long term risks beyond transient response, with consideration for overshoots and the full timescale of Earth system feedbacks. Lessons learnt from past warm climatic phases may also provide insights complementary to projections, albeit without the perspective of rates of changes that is specific to the issue of 1.5°C global warming. This special report is also designed to be complementary from the other reports in preparation for the IPCC Sixth Assessment cycle (AR6), including the special reports on the ocean and the cryosphere, on land use issues, both scheduled for 2019, and the Working Group main assessment reports, scheduled for 2021-2022.

Selection of climate policies under the uncertainties in the Fifth Assessment Report of the IPCC

NASA Astrophysics Data System (ADS)

Drouet, L.; Bosetti, V.; Tavoni, M.

2015-10-01

Strategies for dealing with climate change must incorporate and quantify all the relevant uncertainties, and be designed to manage the resulting risks. Here we employ the best available knowledge so far, summarized by the three working groups of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5; refs , , ), to quantify the uncertainty of mitigation costs, climate change dynamics, and economic damage for alternative carbon budgets. We rank climate policies according to different decision-making criteria concerning uncertainty, risk aversion and intertemporal preferences. Our findings show that preferences over uncertainties are as important as the choice of the widely discussed time discount factor. Climate policies consistent with limiting warming to 2 °C above preindustrial levels are compatible with a subset of decision-making criteria and some model parametrizations, but not with the commonly adopted expected utility framework.

Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Tianyi; Liu, Xiaohong; Ma, Po -Lun

Here, global climate models often underestimate aerosol loadings in China, and these biases can have significant implications for anthropogenic aerosol radiative forcing and climate effects. The biases may be caused by either the emission inventory or the treatment of aerosol processes in the models, or both, but so far no consensus has been reached. In this study, a relatively new emission inventory based on energy statistics and technology, Multi-resolution Emission Inventory for China (MEIC), is used to drive the Community Atmosphere Model version 5 (CAM5) to evaluate aerosol distribution and radiative effects against observations in China. The model results aremore » compared with the model simulations with the widely used Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) emission inventory. We find that the new MEIC emission improves the aerosol optical depth (AOD) simulations in eastern China and explains 22–28 % of the AOD low bias simulated with the AR5 emission. However, AOD is still biased low in eastern China. Seasonal variation of the MEIC emission leads to a better agreement with the observed seasonal variation of primary aerosols than the AR5 emission, but the concentrations are still underestimated. This implies that the atmospheric loadings of primary aerosols are closely related to the emission, which may still be underestimated over eastern China. In contrast, the seasonal variations of secondary aerosols depend more on aerosol processes (e.g., gas- and aqueous-phase production from precursor gases) that are associated with meteorological conditions and to a lesser extent on the emission. It indicates that the emissions of precursor gases for the secondary aerosols alone cannot explain the low bias in the model. Aerosol secondary production processes in CAM5 should also be revisited. The simulation using MEIC estimates the annual-average aerosol direct radiative effects (ADREs) at the top of the atmosphere (TOA), at the surface, and in the atmosphere to be –5.02, –18.47, and 13.45 W m –2, respectively, over eastern China, which are enhanced by –0.91, –3.48, and 2.57 W m –2 compared with the AR5 emission. The differences of ADREs by using MEIC and AR5 emissions are larger than the decadal changes of the modeled ADREs, indicating the uncertainty of the emission inventories. This study highlights the importance of improving both the emission and aerosol secondary production processes in modeling the atmospheric aerosols and their radiative effects. Yet, if the estimations of MEIC emissions in trace gases do not suffer similar biases to those in the AOD, our findings will help affirm a fundamental error in the conversion from precursor gases to secondary aerosols as hinted in other recent studies following different approaches.« less

Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

DOE PAGES

Fan, Tianyi; Liu, Xiaohong; Ma, Po -Lun; ...

2018-02-01

Here, global climate models often underestimate aerosol loadings in China, and these biases can have significant implications for anthropogenic aerosol radiative forcing and climate effects. The biases may be caused by either the emission inventory or the treatment of aerosol processes in the models, or both, but so far no consensus has been reached. In this study, a relatively new emission inventory based on energy statistics and technology, Multi-resolution Emission Inventory for China (MEIC), is used to drive the Community Atmosphere Model version 5 (CAM5) to evaluate aerosol distribution and radiative effects against observations in China. The model results aremore » compared with the model simulations with the widely used Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) emission inventory. We find that the new MEIC emission improves the aerosol optical depth (AOD) simulations in eastern China and explains 22–28 % of the AOD low bias simulated with the AR5 emission. However, AOD is still biased low in eastern China. Seasonal variation of the MEIC emission leads to a better agreement with the observed seasonal variation of primary aerosols than the AR5 emission, but the concentrations are still underestimated. This implies that the atmospheric loadings of primary aerosols are closely related to the emission, which may still be underestimated over eastern China. In contrast, the seasonal variations of secondary aerosols depend more on aerosol processes (e.g., gas- and aqueous-phase production from precursor gases) that are associated with meteorological conditions and to a lesser extent on the emission. It indicates that the emissions of precursor gases for the secondary aerosols alone cannot explain the low bias in the model. Aerosol secondary production processes in CAM5 should also be revisited. The simulation using MEIC estimates the annual-average aerosol direct radiative effects (ADREs) at the top of the atmosphere (TOA), at the surface, and in the atmosphere to be –5.02, –18.47, and 13.45 W m –2, respectively, over eastern China, which are enhanced by –0.91, –3.48, and 2.57 W m –2 compared with the AR5 emission. The differences of ADREs by using MEIC and AR5 emissions are larger than the decadal changes of the modeled ADREs, indicating the uncertainty of the emission inventories. This study highlights the importance of improving both the emission and aerosol secondary production processes in modeling the atmospheric aerosols and their radiative effects. Yet, if the estimations of MEIC emissions in trace gases do not suffer similar biases to those in the AOD, our findings will help affirm a fundamental error in the conversion from precursor gases to secondary aerosols as hinted in other recent studies following different approaches.« less

The Risks of Missing the 2°C Target and the Risks of Framing the Target As 2°C

NASA Astrophysics Data System (ADS)

Nichols, L. H.

2014-12-01

The publication of IPCC AR5 has made it very clear that we are at risk of missing the 2°C target. It has also made it clear that the risks of missing this target would be very dire. But when read through a precautionary lens, it also illustrates potential risks of framing an appropriate climate target as 2°C. We ought to be doing all we can to limit the extent of climate change as much as possible, and framing our target as limiting warming to 2°C may mask the demandingness and urgency of addressing climate change aggressively and holistically. In this session I will summarize my work on what precaution demands in the face of climate change and discuss how it applies to AR5. I argue for a Catastrophic Precautionary Principle that gives us strong moral reasons to take precautionary measures against threats of catastrophe, such as those posed by climate change. I will explain how the IPCC's discussion of the five reasons for concern about climate change support a strong moral argument that we ought to be taking a much more precautionary approach to climate policy than is currently evidenced by UNFCCC agreements and domestic policies around the world. While AR5 supports the conclusion that we should not risk missing the 2°C target, it also supports reevaluating what our target - and more generally what our comprehensive approach to climate policy - should be. In this way, I will discuss the complex science-ethics-policy nexus and the role of climate science in guiding precautionary global climate policies.

The climate crisis: An introductory guide to climate change

NASA Astrophysics Data System (ADS)

Trenberth, Kevin E.

2011-06-01

Human-induced climate change, sometimes called “global warming,” has, unfortunately, become a “hot” topic, embroiled in controversy, misinformation, and claims and counterclaims. It should not be this way, because there are many scientific facts that provide solid information on which to base policy. There is a very strong observational, theoretical, and modeling base in physical science that underpins current understanding of what has happened to Earth's climate and why and what the prospects are for the future under certain assumptions. Moreover, these changes have impacts, which are apt to grow, on the environment and human society. To avoid or reduce these impacts and the economic and human effects of undesirable future climate change requires actions that are strongly opposed by those with vested interests in the status quo, some of whom have funded misinformation campaigns that have successfully confused the public and some politicians, leading to paralysis in political action. Without mitigation of climate change, one would suppose that at least society would plan sensibly for the changes already happening and projected, but such future adaptation plans are also largely in limbo. The implication is that we will suffer the consequences. All of these aspects are addressed in this informative and attractive book, which is written for a fairly general but technically informed audience. The book is strongly based upon the 2007 Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) and therefore has a solid scientific basis. Many figures, graphs, and maps come from the three IPCC working group reports, although the captions often do not explain the detail shown. Given that the IPCC reports totaled nearly 3000 pages, to distill the complex material down to 249 pages is no mean task, and the authors have succeeded quite well.

Relationship between Trends in Land Precipitation and Tropical SST Gradient

NASA Technical Reports Server (NTRS)

Chung, Chul Eddy; Ramanathan, V.

2007-01-01

In this study, we examined global zonal/annual mean precipitation trends. Land precipitation trend from 1951 to 2002 shows widespread drying between 10 S to 20 N but the trend from 1977 to 2002 shows partial recovery. Based on general circulation model sensitivity studies, we suggested that these features are driven largely by the meridional SST gradient trend in the tropics. Our idealized CCM3 experiments substantiated that land precipitation is more sensitive to meridional SST gradient than to an overall tropical warming. Various simulations produced for the IPCC 4th assessment report demonstrate that increasing CO2 increases SST in the entire tropics non-uniformly and increases land precipitation only in certain latitude belts, again pointing to the importance of SST gradient change. Temporally varying aerosols in the IPCC simulations alter meridional SST gradient and land precipitation substantially. Anthropogenic aerosol direct solar forcing without its effects on SST is shown by the CCM3 to have weak but non-negligible influence on land precipitation.

The implications of rebasing global mean temperature timeseries for GCM based climate projections

NASA Astrophysics Data System (ADS)

Stainforth, David; Chapman, Sandra; Watkins, Nicholas

2017-04-01

Global climate and earth system models are assessed by comparison with observations through a number of metrics. The InterGovernmental Panel on Climate Change (IPCC) highlights in particular their ability to reproduce "general features of the global and annual mean surface temperature changes over the historical period" [1,2] and to simulate "a trend in global-mean surface temperature from 1951 to 2012 that agrees with the observed trend" [3]. This focus on annual mean global mean temperature (hereafter GMT) change is presented as an important element in demonstrating the relevance of these models for climate projections. Any new model or new model version whose historic simulations fail to reproduce the "general features " and 20th century trends is likely therefore to undergo further tuning. Thus this focus could have implications for model development. Here we consider a formal interpretation of "general features" and discuss the implications of this approach to model assessment and intercomparison, for the interpretation of GCM projections. Following the IPCC, we interpret a major element of "general features" as being the slow timescale response to external forcings. (Shorter timescale behaviour such as the response to volcanic eruptions are also elements of "general features" but are not considered here.) Also following the IPCC, we consider only GMT anomalies i.e. changes with respect to some period. Since the models have absolute temperatures which range over about 3K (roughly observed GMT +/- 1.5K) this means their timeseries (and the observations) are rebased. We present timeseries of the slow timescale response of the CMIP5 models rebased to late-20th century temperatures and to mid-19th century temperatures. We provide a mathematical interpretation of this approach to model assessment and discuss two consequences. First is a separation of scales which limits the degree to which sub-global behaviour can feedback on the global response. Second, is an implication of linearity in the GMT response (to the extent that the slow-timescale response of the historic simulations is consistent with observations, and given their uncertainties). For each individual model these consequences only apply over the range of absolute temperatures simulated by the model in historic simulations. Taken together, however, they imply consequences over a much wider range of GMTs. The analysis suggests that this aspect of model evaluation risks providing a model development pressure which acts against a wide exploration of physically plausible responses; in particular against an exploration of potentially globally significant nonlinear responses and feedbacks. [1] IPCC, Fifth Assessment Report, Working Group 1, Technical Summary: Stocker et al. 2013. [2] IPCC, Fifth Assessment Report, Working Group 1, Chapter 9 - "Evaluation of Climate Models": Flato et al. 2013. [3] IPCC, Fifth Assessment Report, Working Group 1, Summary for Policy Makers: IPCC, 2013.

ENSO Simulation in Coupled Ocean-Atmosphere Models: Are the Current Models Better?

DOE Office of Scientific and Technical Information (OSTI.GOV)

AchutaRao, K; Sperber, K R

Maintaining a multi-model database over a generation or more of model development provides an important framework for assessing model improvement. Using control integrations, we compare the simulation of the El Nino/Southern Oscillation (ENSO), and its extratropical impact, in models developed for the 2007 Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report with models developed in the late 1990's (the so-called Coupled Model Intercomparison Project-2 [CMIP2] models). The IPCC models tend to be more realistic in representing the frequency with which ENSO occurs, and they are better at locating enhanced temperature variability over the eastern Pacific Ocean. When compared withmore » reanalyses, the IPCC models have larger pattern correlations of tropical surface air temperature than do the CMIP2 models during the boreal winter peak phase of El Nino. However, for sea-level pressure and precipitation rate anomalies, a clear separation in performance between the two vintages of models is not as apparent. The strongest improvement occurs for the modeling groups whose CMIP2 model tended to have the lowest pattern correlations with observations. This has been checked by subsampling the multi-century IPCC simulations in a manner to be consistent with the single 80-year time segment available from CMIP2. Our results suggest that multi-century integrations may be required to statistically assess model improvement of ENSO. The quality of the El Nino precipitation composite is directly related to the fidelity of the boreal winter precipitation climatology, highlighting the importance of reducing systematic model error. Over North America distinct improvement of El Nino forced boreal winter surface air temperature, sea-level pressure, and precipitation rate anomalies in the IPCC models occurs. This improvement, is directly proportional to the skill of the tropical El Nino forced precipitation anomalies.« less

Seeing the risks of multiple Arctic amplifying feedbacks.

NASA Astrophysics Data System (ADS)

Carter, P.

2014-12-01

There are several potentially very large sources of Arctic amplifying feedbacks that have been identified. They present a great risk to the future as they could become self and inter-reinforcing with uncontrollable knock-on, or cascading risks. This has been called a domino effect risk by Carlos Duarte. Because of already committed global warming and the millennial duration of global warming, these are highly policy relevant. These Arctic feedback processes are now all operant with emissions of carbon dioxide methane and nitrous oxide detected. The extent of the risks from these feedback sources are not obvious or easy to understand by policy makers and the public. They are recorded in the IPCC AR5 as potential tipping points, as is the irreversibility of permafrost thaw. Some of them are not accounted for in the IPCC AR5 global warming projections because of quantitative uncertainty. UNEP issued a 2012 report (Policy Implications of Thawing Permafrost) advising that by omitting carbon feedback emissions from permafrost, carbon budget calculations by err on the low side. There is the other unassessed issue of a global warming safety limit for preventing uncontrollable increasing Arctic feedback emissions. Along with our paper, we provide illustrations of the Arctic feedback sources and processes from satellite imagery and flow charts that allows for their qualitative consideration. We rely on the IPCC assessments, the 2012 paper Possible role of wetlands permafrost can methane hydrates in the methane cycle under future climate change; a review, by Fiona M. O'Connor et al., and build on the WWF 2009 Arctic Climate Feedbacks: Global Implications. The potential sources of Arctic feedback processes identified include: Arctic and Far North snow albedo decline, Arctic summer sea ice albedo decline, Greenland summer ice surface melting albedo loss, albedo decline by replacement of Arctic tundra with forest, tundra fires, Boreal forest fires, Boreal forest die-back, warming subarctic peat rich wetlands (methane), thawing permafrost (carbon dioxide, methane and nitrous oxide), and Arctic subsea floor methane.

Projecting Range Limits with Coupled Thermal Tolerance - Climate Change Models: An Example Based on Gray Snapper (Lutjanus griseus) along the U.S. East Coast

PubMed Central

Hare, Jonathan A.; Wuenschel, Mark J.; Kimball, Matthew E.

2012-01-01

We couple a species range limit hypothesis with the output of an ensemble of general circulation models to project the poleward range limit of gray snapper. Using laboratory-derived thermal limits and statistical downscaling from IPCC AR4 general circulation models, we project that gray snapper will shift northwards; the magnitude of this shift is dependent on the magnitude of climate change. We also evaluate the uncertainty in our projection and find that statistical uncertainty associated with the experimentally-derived thermal limits is the largest contributor (∼ 65%) to overall quantified uncertainty. This finding argues for more experimental work aimed at understanding and parameterizing the effects of climate change and variability on marine species. PMID:23284974

Exposure age and ice-sheet model constraints on Pliocene East Antarctic ice sheet dynamics.

PubMed

Yamane, Masako; Yokoyama, Yusuke; Abe-Ouchi, Ayako; Obrochta, Stephen; Saito, Fuyuki; Moriwaki, Kiichi; Matsuzaki, Hiroyuki

2015-04-24

The Late Pliocene epoch is a potential analogue for future climate in a warming world. Here we reconstruct Plio-Pleistocene East Antarctic Ice Sheet (EAIS) variability using cosmogenic nuclide exposure ages and model simulations to better understand ice sheet behaviour under such warm conditions. New and previously published exposure ages indicate interior-thickening during the Pliocene. An ice sheet model with mid-Pliocene boundary conditions also results in interior thickening and suggests that both the Wilkes Subglacial and Aurora Basins largely melted, offsetting increased ice volume. Considering contributions from West Antarctica and Greenland, this is consistent with the most recent IPCC AR5 estimate, which indicates that the Pliocene sea level likely did not exceed +20 m on Milankovitch timescales. The inception of colder climate since ∼3 Myr has increased the sea ice cover and inhibited active moisture transport to Antarctica, resulting in reduced ice sheet thickness, at least in coastal areas.

Simulations show decreasing carbon stocks and potential for carbon emissions in Rocky Mountain forests over the next century.

PubMed

Boisvenue, Céline; Running, Steven W

2010-07-01

Climate change has altered the environment in which forests grow, and climate change models predict more severe alterations to come. Forests have already responded to these changes, and the future temperature and precipitation scenarios are of foremost concern, especially in the mountainous western United States, where forests occur in the dry environments that interface with grasslands. The objective of this study was to understand the trade-offs between temperature and water controls on these forested sites in the context of available climate projections. Three temperature and precipitation scenarios from IPCC AR4 AOGCMs ranging in precipitation levels were input to the process model Biome-BGC for key forested sites in the northern U.S. Rocky Mountains. Despite the omission of natural and human-caused disturbances in our simulations, our results show consequential effects from these conservative future temperature and precipitation scenarios. According to these projections, if future precipitation and temperatures are similar to or drier than the dry scenario depicted here, high-elevation forests on both the drier and wetter sites, which have in the absence of disturbance accumulated carbon, will reduce their carbon accumulation. Under the marginally drier climate projections, most forests became carbon sources by the end of the simulation horizon (2089). Under all three scenarios, growing season lengthened, the number of days with snow on the ground decreased, peak snow occurred earlier, and water stress increased through the projection horizon (1950-2089) for all sites, which represent the temperature and precipitation spectrum of forests in this region. The quantity, form, and timing of precipitation ultimately drive the carbon accumulation trajectory of forests in this region.

Fluid simulation of species concentrations in capacitively coupled N2/Ar plasmas: Effect of gas proportion

NASA Astrophysics Data System (ADS)

Liang, Ying-Shuang; Liu, Gang-Hu; Xue, Chan; Liu, Yong-Xin; Wang, You-Nian

2017-05-01

A two-dimensional self-consistent fluid model and the experimental diagnostic are employed to investigate the dependencies of species concentrations on the gas proportion in the capacitive N2/Ar discharges operated at 60 MHz, 50 Pa, and 140 W. The results indicate that the N2/Ar proportion has a considerable impact on the species densities. As the N2 fraction increases, the electron density, as well as the Ar+ and Arm densities, decreases remarkably. On the contrary, the N2 + density is demonstrated to increase monotonically with the N2 fraction. Moreover, the N density is observed to increase significantly with the N2 fraction at the N2 fractions below 40%, beyond which it decreases slightly. The electrons are primarily generated via the electron impact ionization of the feed gases. The electron impact ionization of Ar essentially determines the Ar+ density. For the N2 + production, the charge transition process between the Ar+ ions and the feed gas N2 dominates at low N2 fraction, while the electron impact ionization of N2 plays the more important role at high N2 fraction. At any gas mixtures, more than 60% Arm atoms are generated through the radiative decay process from Ar(4p). The dissociation of the feed gas N2 by the excited Ar atoms and by the electrons is responsible for the N formation at low N2 fraction and high N2 fraction, respectively. To validate the simulation results, the floating double probe and the optical emission spectroscopy are employed to measure the total positive ion density and the emission intensity originating from Ar(4p) transitions, respectively. The results from the simulation show a qualitative agreement with that from the experiment, which indicates the reliable model.

Scientists' Views about Attribution of Global Warming

NASA Astrophysics Data System (ADS)

Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

2015-04-01

What do scientists think? That is an important question when engaging in science communication, in which an attempt is made to communicate the scientific understanding to a lay audience. To address this question we undertook a large and detailed survey among scientists studying various aspects of climate change , dubbed "perhaps the most thorough survey of climate scientists ever" by well-known climate scientist and science communicator Gavin Schmidt. Among more than 1800 respondents we found widespread agreement that global warming is predominantly caused by human greenhouse gases. This consensus strengthens with increased expertise, as defined by the number of self-reported articles in the peer-reviewed literature. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), agreed that anthropogenic greenhouse gases are the dominant cause of recent global warming, i.e. having contributed more than half of the observed warming. With this survey we specified what the consensus position entails with much greater specificity than previous studies. The relevance of this consensus for science communication will be discussed. Another important result from our survey is that the main attribution statement in IPCC's fourth assessment report (AR4) may lead to an underestimate of the greenhouse gas contribution to warming, because it implicitly includes the lesser known masking effect of cooling aerosols. This shows the importance of the exact wording in high-profile reports such as those from IPCC in how the statement is perceived, even by fellow scientists. The phrasing was improved in the most recent assessment report (AR5). Respondents who characterized the human influence on climate as insignificant, reported having the most frequent media coverage regarding their views on climate change. This shows that contrarian opinions are amplified in the media in relation to their prevalence in the scientific community. This is related to what is sometimes referred to as "false balance" in media reporting and may partly explain the divergence between public and scientific opinion regarding climate change.

High-resolution interpolation of climate scenarios for Canada derived from general circulation model simulations

Treesearch

D. T. Price; D. W. McKenney; L. A. Joyce; R. M. Siltanen; P. Papadopol; K. Lawrence

2011-01-01

Projections of future climate were selected for four well-established general circulation models (GCMs) forced by each of three greenhouse gas (GHG) emissions scenarios recommended by the Intergovernmental Panel on Climate Change (IPCC), namely scenarios A2, A1B, and B1 of the IPCC Special Report on Emissions Scenarios. Monthly data for the period 1961-2100 were...

Historical and potential future impacts of extreme hydrological events on the Amazonian floodplain hydrology and inundation dynamics

NASA Astrophysics Data System (ADS)

Macedo, M.; Panday, P. K.; Coe, M. T.; Lefebvre, P.; Castello, L.

2015-12-01

The Amazonian floodplains and wetlands cover one fifth of the basin and are highly productive promoting diverse biological communities and sustaining human populations with fisheries. Seasonal inundation of the floodplains fluctuates in response to drought or extreme rainfall as observed in the recent droughts of 2005 and 2010 where river levels dropped to among the lowest recorded. We model and evaluate the historical (1940-2010) and projected future (2010-2100) impacts of droughts and floods on the floodplain hydrology and inundation dynamics in the central Amazon using the Integrated Biosphere Simulator (IBIS) and the Terrestrial Hydrology Model and Biogeochemistry (THMB). Simulated discharge correlates well with observed discharges for tributaries originating in Brazil but underestimates basins draining regions in the non-Brazilian Amazon (Solimões, Japuŕa, Madeira, and Negro) by greater than 30%. A volume bias-correction from the simulated and observed runoff was used to correct the input precipitation across the major tributaries of the Amazon basin that drain the Andes. Simulated hydrological parameters (discharge, inundated area and river height) using corrected precipitation has a strong correlation with field measured discharge at gauging stations, surface water extent data (Global Inundation Extent from Multi-Satellites (GIEMS) and NASA Earth System Data Records (ESDRs) for inundation), and satellite radar altimetry (TOPEX/POSEIDON altimeter data for 1992-1998 and ENVISAT data for 2002-2010). We also used an ensemble of model outputs participating in the IPCC AR5 to drive two sets of simulations with and without carbon dioxide fertilization for the 2006-2100 period, and evaluated the potential scale and variability of future changes in discharge and inundation dynamics due to the influences of climate change and vegetation response to carbon dioxide fertilization. Preliminary modeled results for future scenarios using Representative Concentration Pathways (RCP) 4.5 indicate decreases in projected discharge and extent of inundated area on the mainstem Amazon by the late 21st century owing to influences of future climate change only.

Data citation in climate sciences: Improvements in CMIP6 compared to CMIP5

NASA Astrophysics Data System (ADS)

Stockhause, M.; Lautenschlager, M.

2017-12-01

Within CMIP5 (Coupled Model Intercomparison Project Phase 5) the citation of the data was not possible prior its long-term archival in the IPCC Data Distribution Centre (DDC). The Reference Data Archive for AR5 (Assessment Report 5) was built up after the submission deadline for part 1 of the AR5. This was too late for many scientific articles. But even the AR5 data in the IPCC DDC is rarely cited in literature in spite of annual download volumes between one and three PBytes. On the other hand, the request for a citation possibility for the evolving CMIP6 data prior to long-term archival came from the CMIP6 data providers. The additional provision of data citations for the project input4MIPs (input data for CMIP6) could raise the scientists' awareness of the discrepancy between the readiness to cite data and the desire to be cited and get credit. The CMIP6 Citation Service is a pragmatic approach built on existing services and services under development, such as ESGF (Earth System Grid Federation) as data infrastructure component, DataCite as DOI registration agency, and Scholix services for tracking data usage information. Other principles followed to overcome barriers of data citation are: Collect data and literature references in the data citation metadata to enable data-data and data-literature interlinking. Visibility of data citation information in the ESGF data portals (low barrier to access data citation information) Provide data usage information in literature for the data providers, data node managers and their funders (requested by some ESGF data node managers) The CMIP6 Citation Service is an implementation only of the credit part of the RDA WGDC recommendation for the citation of dynamic data. The second part, the identification of the data subset underlying an article, is planned for CMIP7 as a data cart approach comprising multiple pre-defined CMIP6 DataCite DOIs. Additional policies on the long-term data availability are required. References: M. Stockhause and M. Lautenschlager (2017). CMIP6 Data Citation of Evolving Data. Data Science Journal. 16, p.30. doi:10.5334/dsj-2017-030. https://doi.org/10.5334/dsj-2017-030 . http://cmip6cite.wdc-climate.de

Investigating the Greenland ice sheet evolution under changing climate using a three-dimensional full-Stokes model

NASA Astrophysics Data System (ADS)

Seddik, H.; Greve, R.; Zwinger, T.; Gillet-Chaulet, F.; Gagliardini, O.

2010-12-01

A three-dimensional, thermo-mechanically coupled model is applied to the Greenland ice sheet. The model implements the full-Stokes equations for the ice dynamics, and the system is solved with the finite-element method (FEM) using the open source multi-physics package Elmer (http://www.csc.fi/elmer/). The finite-element mesh for the computational domain has been created using the Greenland surface and bedrock DEM data with a spatial resolution of 5 km (SeaRise community effort, based on Bamber and others, 2001). The study is particularly aimed at better understanding the ice dynamics near the major Greenland ice streams. The meshing procedure starts with the bedrock footprint where a mesh with triangle elements and a resolution of 5 km is constructed. Since the resulting mesh is unnecessarily dense in areas with slow ice dynamics, an anisotropic mesh adaptation procedure has been introduced. Using the measured surface velocities to evaluate the Hessian matrix of the velocities, a metric tensor is computed at the mesh vertices in order to define the adaptation scheme. The resulting meshed footprint obtained with the automatic tool YAMS shows a high density of elements in the vicinities of the North-East Greenland Ice Stream (NEGIS), the Jakobshavn ice stream (JIS) and the Kangerdlugssuaq (KL) and Helheim (HH) glaciers. On the other hand, elements with a coarser resolution are generated away from the ice streams and domain margins. The final three-dimensional mesh is obtained by extruding the 2D footprint with 21 vertical layers, so that the resulting mesh contains 400860 wedge elements and 233583 nodes. The numerical solution of the Stokes and the heat transfer equations involves direct and iterative solvers depending on the simulation case, and both methods are coupled with stabilization procedures. The boundary conditions are such that the temperature at the surface uses the present-day mean annual air temperature given by a parameterization or directly from the available data, the geothermal heat flux at the bedrock is prescribed as spatially constant and the lateral sides are open boundaries. A non-linear Weertman law is used for the basal sliding. The project goal is to better assess the effects of dynamical changes of the Greenland ice sheet on sea level rise under global-warming conditions. Hence, the simulations have been conducted in order to investigate the ice sheet evolution using the climate forcing experiments defined in the SeaRISE project. For that purpose, four different experiments have been conducted, (i) constant climate control run beginning at present (epoch 2004-1-1 0:0:0) and running up to 500 years holding the climate constant to its present state, (ii) constant climate forcing with increased basal lubrication, (iii) AR4 climate run forced by anomalies derived from results given in the IPCC 4th Assessment Report (AR4) for the A1B emission scenario, (iv) AR4 climate run with increased basal lubrication.

Methane emissions associated with the conversion of marshland to cropland and climate change on the Sanjiang Plain of northeast China from 1950 to 2100

NASA Astrophysics Data System (ADS)

Li, T.; Huang, Y.; Zhang, W.; Yu, Y.-Q.

2012-12-01

Wetland loss and climate change are known to alter regional and global methane (CH4) budgets. Over the last six decades, an extensive area of marshland has been converted to cropland on the Sanjiang Plain in northeast China, and a significant increase in air temperature has also been observed there, while the impacts on regional CH4 budgets remain uncertain. Through model simulation, we estimated the changes in CH4 emissions associated with the conversion of marshland to cropland and climate change in this area. Model simulations indicated a significant reduction of 1.1 Tg yr-1 (0.7-1.8 Tg yr-1) from the 1950s to the 2000s in regional CH4 emissions. The cumulative reduction of CH4 from 1960 to 2009 was estimated to be ~36 Tg (24-57 Tg) relative to the 1950s, and marshland conversion and the climate contributed 86% and 14% of this change, respectively. Interannual variation in precipitation (linear trend with P > 0.2) contributed to yearly fluctuations in CH4 emissions, but the relatively lower amount of precipitation over the period 1960-2009 (47 mm yr-1 lower on average than in the 1950s) contributed ~91% of the reduction in the area-weighted CH4 flux. Global warming at a rate of 0.3 ° per decade (P < 0.001) has increased CH4 emissions significantly since the 1990s. Relative to the mean of the 1950s, the warming-induced increase in the CH4 flux has averaged 19 kg ha-1 yr-1 over the last two decades. In the RCP (Representative Concentration Pathway) 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 scenarios of the fifth IPCC assessment report (AR5), the CH4 fluxes are predicted to increase by 36%, 52%, 78% and 95%, respectively, by the 2080s compared to 1961-1990 in response to climate warming and wetting.

Calcium affecting protein expression in longan under simulated acid rain stress.

PubMed

Pan, Tengfei; Li, Yongyu; Ma, Cuilan; Qiu, Dongliang

2015-08-01

Longan (Dimocarpus longana Lour. cv. Wulongling) of uniform one-aged seedlings grown in pots were selected to study specific proteins expressed in leaves under simulated acid rain (SiAR) stress and exogenous Ca(2+) regulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results showed that there was a protein band specifically expressed under SiAR of pH 2.5 stress for 15 days with its molecular weight of about 23 kD. A 17 kD protein band specifically expressed after SiAR stress 5 days. Compared with pH 2.5, the pH 3.5 of SiAR made a less influence to protein expression. Two-dimensional electrophoresis (2-DE) results showed that six new specific proteins including C4 (20.2 kD pI 6.0), F (24 kD pI 6.35), B3 (22.3 kD pI 6.35), B4 (23.5 kD pI 6.5), C5 (21.8 kD pI 5.6), and C6 (20.2 kD pI 5.6) specifically expressed. C4 always expressed during SiAR stress. F expressed under the stress of pH 2.5 for 15 days and expressed in all pH SiAR stress for 20 days. The expression of proteins including B3, C5, and C6 was related to pH value and stress intensity of SiAR. The expression of B4 resulted from synergistic effects of SiAR and Ca. The expression of G1 (Mr 19.3 kD, pI 4.5), G2 (Mr 17.8 kD, pI 4.65), G3 (Mr 16.6 kD, pI 4.6), and G4 (Mr 14.7 kD, pI 4.4) enhanced under the treatment of 5 mM ethylene glycol tetraacetic acid (EGTA) and 2 mM chlorpromazine (CPZ). These proteins showed antagonistic effects and might be relative to the Ca-calmodulin (Ca-CaM) system of longan in response to SiAR stress.

Long-term climate change commitment and reversibility: An EMIC intercomparison

NASA Astrophysics Data System (ADS)

Zickfeld, K.; Eby, M.; Weaver, A. J.

2012-12-01

This paper summarizes the results of an intercomparison project with Earth System Models of Intermediate Complexity (EMICs) undertaken in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The focus is on long-term climate projections designed to: (i) quantify the climate change "commitment" of a range of radiative forcing trajectories, and (ii) explore the extent to which climate change is reversible if atmospheric CO2 is left to evolve freely or is artificially restored to pre-industrial levels. All commitment simulations follow the four Representative Concentration Pathways (RCPs) and their extensions to 2300. Most EMICs simulate significant surface air temperature and thermosteric sea level rise commitment following stabilization of the atmospheric composition at year-2300 levels. The additional warming by the year 3000 is 0.0-0.6 °C for RCP4.5 and 0.0-1.2 °C for RCP8.5, and the additional sea level rise is 0.1-1.0 m for RCP4.5 and 0.4-2.6 m for RCP8.5. Elimination of anthropogenic CO2 emissions results in constant or slightly decreasing surface air temperature in all EMICs. Thermosteric sea level rise continues after elimination of anthropogenic CO2 emissions, with additional sea level rise between 2300 and 3000 of 0.0-0.5 m for RCP4.5 and 0.2-2.4 m for RCP8.5. The largest warming and sea level rise commitment are simulated for the case with constant year-2300 CO2 emissions. Restoration of atmospheric CO2 from RCP to pre-industrial levels over 100-1000 years does not result in the simultaneous return to pre-industrial climate conditions, as surface air temperature and sea level rise exhibit a substantial time lag relative to atmospheric CO2, and requires large artificial removal of CO2 from the atmosphere. Results of the climate change commitment and reversibility simulations differ widely among EMICs, both in the physical and biogeochemical response. Particularly large differences are identified in the response of the terrestrial carbon cycle to atmospheric CO2 and climate, highlighting the need for improved understanding and representation of land carbon cycle processes in Earth System models.

Improvement of downscaled rainfall and temperature across generations over the Western Himalayan region of India

NASA Astrophysics Data System (ADS)

Das, L.; Dutta, M.; Akhter, J.; Meher, J. K.

2016-12-01

It is a challenging task to create station level (local scale) climate change information over the mountainous locations of Western Himalayan Region (WHR) in India because of limited data availability and poor data quality. In the present study, missing values of station data were handled through Multiple Imputation Chained Equation (MICE) technique. Finally 22 numbers of rain gauge and 16 number of temperature station data having continuous record during 1901­2005 and 1969­2009 period respectively were considered as reference stations for developing downscaled rainfall and temperature time series from five commonly available GCMs in the IPCC's different generation assessment reports namely 2nd, 3rd, 4th and 5th hereafter known as SAR, TAR, AR4 and AR5 respectively. Downscaled models were developed using the combined data from the ERA-interim reanalysis and GCMs historical runs (in spite of forcing were not identical in different generation) as predictor and station level rainfall and temperature as predictands. Station level downscaled rainfall and temperature time series were constructed for five GCMs available in each generation. Regional averaged downscaled time series comprising of all stations was prepared for each model and generation and the downscaled results were compared with observed time series. Finally an Overall Model Improvement Index (OMII) was developed using the downscaling results, which was used to investigate the model improvement across generations as well as the improvement of downscaling results obtained from the Empirical Statistical Downscaling (ESD) methods. In case of temperature, models have improved from SAR to AR5 over the study area. In all most all the GCMs TAR is showing worst performance over the WHR by considering the different statistical indices used in this study. In case of precipitation, no model has shown gradual improvement from SAR to AR5 both for interpolated and downscaled values.

High-mass heterogeneous cluster formation by ion bombardment of the ternary alloy Au 7Cu 5Al 4

DOE PAGES

Zinovev, Alexander V.; King, Bruce V.; Veryovkin, Igor V.; ...

2016-02-04

The ternary alloy Au 7Cu 5Al 4 was irradiated with 0.1–10 keV Ar + and the surface composition analyzed using laser sputter neutral mass spectrometry. Ejected clusters containing up to seven atoms, with masses up to 2000 amu, were observed. By monitoring the signals from sputtered clusters, the surface composition of the alloy was seen to change with 100 eV Ar + dose, reaching equilibrium after 10 nm of the surface was eroded, in agreement with TRIDYN simulation and indicating that the changes were due to preferential sputtering of Al and Cu. Ejected gold containing clusters were found to increasemore » markedly in intensity while aluminum containing clusters decreased in intensity as a result of Ar sputtering. Such an effect was most pronounced for low energy (<1 keV) Ar + sputtering and was consistent with TRIDYN simulations of the depth profiling. As a result, the component sputter yields from the ternary alloy were consistent with previous binary alloy measurements but showed greater Cu surface concentrations than expected from TRIDYN simulations.« less

Observation of Wetland Dynamics with Global Navigation Satellite Signals Reflectometry

NASA Astrophysics Data System (ADS)

Zuffada, C.; Shah, R.; Nghiem, S. V.; Cardellach, E.; Chew, C. C.

2015-12-01

Wetland dynamics is crucial to changes in both atmospheric methane and terrestrial water storage. The Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5) highlights the role of wetlands as a key driver of methane (CH4) emission, which is more than one order of magnitude stronger than carbon dioxide as a greenhouse gas in the centennial time scale. Among the multitude of methane emission sources (hydrates, livestock, rice cultivation, freshwaters, landfills and waste, fossil fuels, biomass burning, termites, geological sources, and soil oxidation), wetlands constitute the largest contributor with the widest uncertainty range of 177-284 Tg(CH4) yr-1 according to the IPCC estimate. Wetlands are highly susceptible to climate change that might lead to wetland collapse. Such wetland destruction would decrease the terrestrial water storage capacity and thus contribute to sea level rise, consequently exacerbating coastal flooding problems. For both methane change and water storage change, wetland dynamics is a crucial factor with the largest uncertainty. Nevertheless, a complete and consistent map of global wetlands still needs to be obtained as the Ramsar Convention calls for a wetlands inventory and impact assessment. We develop a new method for observations of wetland change using Global Navigation Satellite Signals Reflectometry (GNSS-R) signatures for global wetland mapping in synergy with the existing capability, not only as a static inventory but also as a temporal dataset, to advance the capability for monitoring the dynamics of wetland extent relevant to addressing the science issues of CH4 emission change and terrestrial water storage change. We will demonstrate the capability of the new GNSS-R method over a rice field in the Ebro Delta wetland in Spain.

Elevated nitrogen metabolism and nitric oxide production are involved in Arabidopsis resistance to acid rain.

PubMed

Qiao, Fang; Zhang, Xi-Min; Liu, Xiang; Chen, Juan; Hu, Wen-Jun; Liu, Ting-Wu; Liu, Ji-Yun; Zhu, Chun-Quan; Ghoto, Kabir; Zhu, Xue-Yi; Zheng, Hai-Lei

2018-06-01

Acid rain (AR) can induce great damages to plants and could be classified into different types according to the different SO 4 2- /NO 3 - ratio. However, the mechanism of plants' responding to different types of AR has not been elucidated clearly. Here, we found that nitric-rich simulated AR (N-SiAR) induced less leaves injury as lower necrosis percentage, better physiological parameters and reduced oxidative damage in the leaves of N-SiAR treated Arabidopsis thaliana compared with sulfate and nitrate mixed (SN-SiAR) or sulfuric-rich (S-SiAR) simulated AR treated ones. Of these three types of SiAR, N-SiAR treated Arabidopsis maintained the highest of nitrogen (N) content, nitrate reductase (NR) and nitrite reductase (NiR) activity as well as N metabolism related genes expression level. Nitric oxide (NO) content showed that N-SiAR treated seedlings had a higher NO level compared to SN-SiAR or S-SiAR treated ones. A series of NO production and elimination related reagents and three NO production-related mutants were used to further confirm the role of NO in regulating acid rain resistance in N-SiAR treated Arabidopsis seedlings. Taken together, we concluded that an elevated N metabolism and enhanced NO production are involved in the tolerance to different types of AR in Arabidopsis. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Model Estimate of Pan-Arctic Lakes and Wetlands Methane Emissions and Their Future Climate Response

NASA Astrophysics Data System (ADS)

Chen, X.; Bohn, T. J.; Maksyutov, S. S.; Lettenmaier, D. P.

2013-12-01

Lakes and wetlands are important sources of the greenhouse gas CH4, whose emission rate is sensitive to climate. The northern high latitudes, which are especially susceptible to climate change, contain about 50% of the world's lakes and wetlands. Given predicted changes in the climate of this region over the next century (IPCC AR5 scenarios), there is concern about a possible positive feedback resulting from methane emissions from the region's wetlands and lakes. To study the climate response of emissions from northern high latitude lakes and wetlands, we employed a large-scale hydrology and carbon cycling model (Variable Infiltration Capacity model; VIC) over the Pan-Arctic domain, which was linked to an atmospheric model (Japan's National Institute of Environmental Studies transport model; NIES TM). In particular, the VIC model simulates the land surface hydrology and carbon cycling across a dynamic lake-wetland continuum, while NIES TM models the atmospheric mixing and 3-dimension transport of methane emitted. The VIC model includes a distributed wetland water table scheme, which accounts for microtopography around the lakes and simulates variations in inundated area that are calibrated to match a passive microwave based inundation product. Per-unit-area carbon uptake and methane emissions at the land surface have been calibrated using extensive in situ observations at West Siberia. Also, the atmospheric methane concentration from this linked model run was verified for the recent 5 years with satellite observations from Aqua's Atmospheric Infrared Sounder (AIRS) and Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instruments. Using RCP4.5 and RCP8.5 future climate scenarios, we examine CH4 emissions from high latitude lakes and wetlands, as well as their net greenhouse warming potential, over the next 3 centuries across the Pan-Arctic domain. We also assess relative uncertainties in emissions from each of the sources.

High resolution modeling of the upper troposphere and lower stratosphere region over the Arctic - GEM-AC simulations for the future climate with and without aviation emissions.

NASA Astrophysics Data System (ADS)

Porebska, Magdalena; Struzewska, Joanna; Kaminski, Jacek W.

2016-04-01

Upper troposphere and lower stratosphere (UTLS) region is a layer around the tropopause. Perturbation of the chemical composition in the UTLS region can impact physical and dynamical processes that can lead to changes in cloudiness, precipitation, radiative forcing, stratosphere-troposphere exchange and zonal flow. The objective of this study is to investigate the potential impacts of aviation emissions on the upper troposphere and lower stratosphere. In order to assess the impact of the aviation emissions we will focus on changes in atmospheric dynamic due to changes in chemical composition in the UTLS over the Arctic. Specifically, we will assess perturbations in the distribution of the wind, temperature and pressure fields in the UTLS region. Our study will be based on simulations using a high resolution chemical weather model for four scenarios of current (2006) and future (2050) climate: with and without aircraft emissions. The tool that we use is the GEM-AC (Global Environmental Multiscale with Atmospheric Chemistry) chemical weather model where air quality, free tropospheric and stratospheric chemistry processes are on-line and interactive in an operational weather forecast model of Environment Canada. In vertical, the model domain is defined on 70 hybrid levels with model top at 0.1 mb. The gas-phase chemistry includes detailed reactions of Ox, NOx, HOx, CO, CH4, ClOx and BrO. Also, the model can address aerosol microphysics and gas-aerosol partitioning. Aircraft emissions are from the AEDT 2006 database developed by the Federal Aviation Administration (USA) and the future climate simulations are based on RCP8.5 projection presented by the IPCC in the fifth Assessment Report AR5. Results from model simulations on a global variable grid with 0.5o x 0.5o uniform resolution over the Arctic will be presented.

How to `Elk-test' biogeochemical models in a data rich world? (Invited)

NASA Astrophysics Data System (ADS)

Reichstein, M.; Ciais, P.; Seneviratne, S. I.; Carvalhais, N.; Dalmonech, D.; Jung, M.; Luo, Y.; Mahecha, M. D.; Moffat, A. M.; Tomelleri, E.; Zaehle, S.

2010-12-01

Process-oriented biogeochemical models are a primary tool that has been used to project future states of climate and ecosystems in the earth system in response to anthropogenic and other forcing, and receive tremendous attention also in the context us the planned assessment report AR5 by the IPCC. However, model intercomparison and data-model comparison studies indicate large uncertainties regarding predictions of global interactions between atmosphere and biosphere. Rigorous scientific testing of these models is essential but very challenging, largely because neither it is technically and ethically possible to perform global earth-scale experiments, nor do we have replicate Earths for hypothesis testing. Hence, model evaluations have to rely on monitoring data such as ecological observation networks, global remote sensing or short-term and small-scale experiments. Here, we critically examine strategies of how model evaluations have been performed with a particular emphasis on terrestrial ecosystems. Often weak ‘validations’ are being presented which do not take advantage of all the relevant information in the observed data, but also apparent falsifications are made, that are hampered by a confusion of system processes with system behavior. We propose that a stronger integration of recent advances in pattern-oriented and system-oriented methodologies will lead to more satisfying earth system model evaluation and development, and show a few enlightening examples from terrestrial biogeochemical modeling and other disciplines. Moreover it is crucial to take advantage of the multidimensional nature of arising earth observation data sets which should be matched by models simultaneously, instead of relying on univariate simple comparisons. A new critical model evaluation is needed to improve future IPCC assessments in order to reduce uncertainties by distinguishing plausible simulation trajectories from fairy tales.

Investigation of the climate change within Moscow metropolitan area

NASA Astrophysics Data System (ADS)

Varentsov, Mikhail; Trusilova, Kristina; Konstantinov, Pavel; Samsonov, Timofey

2014-05-01

As the urbanization continues worldwide more than half of the Earth's population live in the cities (U.N., 2010). Therefore the vulnerability of the urban environment - the living space for millions of people - to the climate change has to be investigated. It is well known that urban features strongly influence the atmospheric boundary layer and determine the microclimatic features of the local environment, such as urban heat island (UHI). Available temperature observations in cities are, however, influenced by the natural climate variations, human-induced climate warming (IPCC, 2007) and in the same time by the growth and structural modification of the urban areas. The relationship between these three factors and their roles in climate changes in the cities are very important for the climatic forecast and requires better understanding. In this study, we made analysis of the air temperature change and urban heat island evolution within Moscow urban area during decades 1970-2010, while this urban area had undergone intensive growth and building modification allowing the population of Moscow to increase from 7 to 12 million people. Analysis was based on the data from several meteorological stations in Moscow region and Moscow city, including meteorological observatory of Lomonosov Moscow State University. Differences in climate change between urban and rural stations, changes of the power and shape of urban heat island and their relationships with changes of building height and density were investigated. Collected data and obtained results are currently to be used for the validation of the regional climate model COSMO-CLM with the purpose to use this model for further more detailed climate research and forecasts for Moscow metropolitan area. References: 1. U.N. (2010), World Urbanization Prospects. The 2009 Revision.Rep., 1-47 pp, United Nations. Department of Economic and Social Affairs. Population Division., New York. 2. IPCC (2007), IPCC Fourth Assessment Report: Climate Change 2007 (AR4) Rep.,Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Historical and Possible Future Changes in Permafrost and Active Layer Thickness in Alaska: Implications to Landscape Changes and Permafrost Carbon Pool.

NASA Astrophysics Data System (ADS)

Marchenko, S. S.; Helene, G.; Euskirchen, E. S.; Breen, A. L.; McGuire, D.; Rupp, S. T.; Romanovsky, V. E.; Walsh, J. E.

2017-12-01

The Soil Temperature and Active Layer Thickness (ALT) Gridded Data was developed to quantify the nature and rate of permafrost degradation and its impact on ecosystems, infrastructure, CO2 and CH4 fluxes and net C storage following permafrost thaw across Alaska. To develop this database, we used the process-based permafrost dynamics model GIPL2 developed in the Geophysical Institute Permafrost Lab, UAF and which is the permafrost module of the Integrated Ecosystem Model (IEM) for Alaska and Northwest Canada. The climate forcing data for simulations were developed by the Scenarios Network for Alaska and Arctic Planning (SNAP, http://www.snap.uaf.edu/). These data are based on the historical CRU3.1 data set for the retrospective analysis period (1901-2009) and the five model averaged data were derived from the five CMIP5/AR5 IPCC Global Circulation Models that performed the best in Alaska and other northern regions: NCAR-CCSM4, GFDL-CM3, GISS-E2-R, IPSL-CM5A-LR, MRI-CGCM3. A composite of all five-model outputs for the RCP4.5 and RCP8.5 were used in these particular permafrost dynamics simulations. Data sets were downscaled to a 771 m resolution, using the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climatology. Additional input data (snow characteristics, soil thermal properties, soil water content, organic matter accumulation or its loss due to fire, etc.) came from the Terrestrial Ecosystem Model (TEM) and the ALFRESCO (ALaska FRame-based EcoSystem COde) model simulations. We estimated the dynamics of permafrost temperature, active layer thickness, area occupied by permafrost, and volume of seasonally thawed soils within the 4.75 upper meters (original TEM soil column) across the Alaska domain. Simulations of future changes in permafrost indicate that, by the end of the 21st century, late-Holocene permafrost in Alaska will be actively thawing at all locations and that some Late Pleistocene carbon-rich peatlands underlain by permafrost will start to thaw at some locations. The modeling results also indicate how different types of ecosystems affect the thermal state of permafrost and its stability. The release of carbon and the net effect of this thawing depends on the balance between increased productivity and respiration, which depend, in part, on soil moisture dynamics.

A Brazilian Vulnerability Index Towards Natural Disasters and Climatic Change - Flashfloods and Landslides.

NASA Astrophysics Data System (ADS)

Debortoli, N. S.; Camarinha, P. I., Sr.; Marengo, J. A.; Rodrigues, R.

2015-12-01

There are some evidences that hydrological climate extremes events have become more frequent an intense in the last decades due to climatic change. In Brazil, flashfloods and landslides were responsible for 74% of the deaths related to natural disasters in 1991-2010 period. In this sense, climate change could be considered a threat which can further increase these numbers, if actions of adaptation and reducing vulnerability are not taken. To evaluate Brazil's vulnerability hotspots to these disasters, two vulnerability indexes were developed using three sets of variables: (1) climate, with IPCC climate extreme indexes; (2) environmental, including land use, drainage systems, relief map, slope, road density and hydrography variables; (3) socioeconomic, including Gini coefficient, HDI (Human Development Index), housing conditions and poverty-related index. The variables were normalized on a scale between 0 to 1 and related using Map Algebra technique (ArcGIS). As part of the effort to contribute to the elaboration of the Third National Communication to the United Nations Framework Convention on Climate Change (UNFCCC), and to contribute to the assessment of impacts on strategic country's issues, simulations at higher resolution were carried out using Eta-20km RCM (Regional Climate Model) nested with two global climate models: HadGEM ES and MIROC 5 (INPE Brazilian National Institute for Space Research). For the baseline period of 1961-1990, the vulnerability indexes were adjusted by an iterative process, which was validated by comparing it to the Brazilian National Disasters Data. The same indexes found at baseline were used to estimate the vulnerability until the end of the XXI century, using the 4.5 and 8.5 IPCC/AR5 RCP (Representative Concentration Pathways) scenarios. The results indicate a large increase in Brazil's vulnerability to landslides mainly in coastal zone, southern states, high lands of southeast states, and along the Amazon River due to climatic aspects only, not considering other factors such as increase in population size, etc. Flashfloods vulnerability, on the other hand, increases mostly in the south/southeast regions, the northeast coastal zone and parts of the Amazon basin. Funded by: Ministry of Science and Technology of Brazil and the United Nations Development Program in Brazil.

To What Extent Can Vegetation Mitigate Greenhouse Warming? A Modeling Approach

NASA Technical Reports Server (NTRS)

Bounoua, L.; Hall, F.G.; Collatz, G.J.; Tucker, C.J.; Sellers, P.J.; Kumar, A.

2008-01-01

Climate models participating in the IPCC Fourth Assessment Report indicate that under a 2xCO2 environment, runoff would increase faster than precipitation overland. However, observations over large U.S watersheds indicate otherwise. This inconsistency suggests that there may be important feedbacks between climate and land surface unaccounted for in the present generation of models. We postulate that the increase in precipitation associated with the increase in CO2 is also increasing vegetation density, which may already be feeding back onto climate. Including this feedback in a climate model simulation resulted in precipitation and runoff trends consistent with observations and reduced the warming by 0.6OC overland. This unaccounted for missing water may be linked to about 10% of the missing land carbon sink. A recent compilation of outputs from 19 coupled atmosphere-ocean general circulation models used in the IPCC Fourth Assessment Report (AR4) shows projected increases in air temperature, precipitation and river discharge for 24 major rivers in the world in response to doubling CO2 by the end of the century (1). The ensemble mean from these models also indicates that, compared to their respective baselines overland, the global mean of the runoff change would increase faster (8.9% per year) than that of the precipitation (5% per year). We analyze century-scale observed annual runoff time-series (1901-2002) over 9 hydrological units covering large regions of the Eastern United States (Fig.1) compiled by the United States Geological Survey (USGS)(2). These regions were selected because they are the most forested; the least water-limited and are not under extensive irrigation. We compare these time-series to similar time-series of observed annual precipitation anomalies spanning the period 1900-1995 (3). Both time-series exhibit a positive longterm trend (Fig. 2); however, in contrast to the analysis of (I), these historic data records show that the rate of precipitation increase is 5.5 % per year, roughly double the rate of runoff increase of 3.1 % per year.

Ranking GCM Estimates of Twentieth Century Precipitation Seasonality in the Western U.S. and its Influence on Floristic Provinces.

NASA Astrophysics Data System (ADS)

Cole, K. L.; Eischeid, J. K.; Garfin, G. M.; Ironside, K.; Cobb, N. S.

2008-12-01

Floristic provinces of the western United States (west of 100W) can be segregated into three regions defined by significant seasonal precipitation during the months of: 1) November-March (Mediterranean); 2) July- September (Monsoonal); or, 3) May-June (Rocky Mountain). This third region is best defined by the absence of the late spring-early summer drought that affects regions 1 and 2. Each of these precipitation regimes is characterized by distinct vegetation types and fire seasonality adapted to that particular cycle of seasonal moisture availability and deficit. Further, areas where these regions blend from one to another can support even more complex seasonal patterns and resulting distinctive vegetation types. As a result, modeling the effects of climates on these ecosystems requires confidence that GCMs can at least approximate these sub- continental seasonal precipitation patterns. We evaluated the late Twentieth Century (1950-1999 AD) estimates of annual precipitation seasonality produced by 22 GCMs contained within the IPCC Fourth Assessment (AR4). These modeled estimates were compared to values from the PRISM dataset, extrapolated from station data, over the same historical period for the 3 seasonal periods defined above. The correlations between GCM estimates and PRISM values were ranked using 4 measures: 1) A map pattern relationship based on the correlation coefficient, 2) A map pattern relationship based on the congruence coefficient, 3) The ratio of simulated/observed area averaged precipitation based on the seasonal precipitation amounts, and, 4) The ratio of simulated/observed area averaged precipitation based on the seasonal precipitation percentages of the annual total. For each of the four metrics, the rank order of models was very similar. The ranked order of the performance of the different models quantified aspects of the model performance visible in the mapped results. While some models represented the seasonal patterns very well, others showed little correspondence with the regional patterns, especially for the summer monsoon period. These sub-continental patterns were especially well simulated over this period by the UKMO-HadGEM1, ECHAM5/MPI-OM, and the MRI-CGCM2 model runs.

Analysis of Changes in the Lorenz Energy Budget of the Atmosphere

NASA Astrophysics Data System (ADS)

Ellis, T. D.

2009-12-01

Several recent papers have addressed the topic of changes in global precipitation rates related to changes in Earth's global energy balance. Less studied are the processes that may be governing the large-scale regional distribution of precipitation around the globe. This study uses the energy budget partition paradigm first put forth by Lorenz (1955) and follows the methodology of Arpé et al. (1986) and Oriol (1982) to identify latitude bands where the partition of energy amongst zonal and eddy kinetic and potential energy bins may account for the spatial patterns of precipitation change predicted by many IPCC AR4 models. In doing so, this study may help to identify whether or not the climate change predicted by these models is indeed creating enhanced baroclinic storms in the mid-latitudes or if there are other mechanisms at work producing the patterns of precipitation change.

Atmospheric Aerosol Properties and Climate Impacts

NASA Technical Reports Server (NTRS)

Chin, Mian; Kahn, Ralph A.; Remer, Lorraine A.; Yu, Hongbin; Rind, David; Feingold, Graham; Quinn, Patricia K.; Schwartz, Stephen E.; Streets, David G.; DeCola, Phillip;

Regional landfills methane emission inventory in Malaysia.

PubMed

Abushammala, Mohammed F M; Noor Ezlin Ahmad Basri; Basri, Hassan; Ahmed Hussein El-Shafie; Kadhum, Abdul Amir H

2011-08-01

The decomposition of municipal solid waste (MSW) in landfills under anaerobic conditions produces landfill gas (LFG) containing approximately 50-60% methane (CH(4)) and 30-40% carbon dioxide (CO(2)) by volume. CH(4) has a global warming potential 21 times greater than CO(2); thus, it poses a serious environmental problem. As landfills are the main method for waste disposal in Malaysia, the major aim of this study was to estimate the total CH(4) emissions from landfills in all Malaysian regions and states for the year 2009 using the IPCC, 1996 first-order decay (FOD) model focusing on clean development mechanism (CDM) project applications to initiate emission reductions. Furthermore, the authors attempted to assess, in quantitative terms, the amount of CH(4) that would be emitted from landfills in the period from 1981-2024 using the IPCC 2006 FOD model. The total CH(4) emission using the IPCC 1996 model was estimated to be 318.8 Gg in 2009. The Northern region had the highest CH(4) emission inventory, with 128.8 Gg, whereas the Borneo region had the lowest, with 24.2 Gg. It was estimated that Pulau Penang state produced the highest CH(4) emission, 77.6 Gg, followed by the remaining states with emission values ranging from 38.5 to 1.5 Gg. Based on the IPCC 1996 FOD model, the total Malaysian CH( 4) emission was forecast to be 397.7 Gg by 2020. The IPCC 2006 FOD model estimated a 201 Gg CH(4) emission in 2009, and estimates ranged from 98 Gg in 1981 to 263 Gg in 2024.

Defining climate change scenario characteristics with a phase space of cumulative primary energy and carbon intensity

NASA Astrophysics Data System (ADS)

Ritchie, Justin; Dowlatabadi, Hadi

2018-02-01

Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing. Scenarios of socio-technical development consistent with end-of-century forcing levels are commonly produced by integrated assessment models. However, outlooks for forcing from fossil energy combustion can also be presented and defined in terms of two essential components: total energy use this century and the carbon intensity of that energy. This formulation allows a phase space diagram to succinctly describe a broad range of possible outcomes for carbon emissions from the future energy system. In the following paper, we demonstrate this phase space method with the Representative Concentration Pathways (RCPs) as used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The resulting RCP phase space is applied to map IPCC Working Group III (WGIII) reference case ‘no policy’ scenarios. Once these scenarios are described as coordinates in the phase space, data mining techniques can readily distill their core features. Accordingly, we conduct a k-means cluster analysis to distinguish the shared outlooks of these scenarios for oil, gas and coal resource use. As a whole, the AR5 database depicts a transition toward re-carbonization, where a world without climate policy inevitably leads to an energy supply with increasing carbon intensity. This orientation runs counter to the experienced ‘dynamics as usual’ of gradual decarbonization, suggesting climate change targets outlined in the Paris Accord are more readily achievable than projected to date.

Cumulative carbon emissions budgets consistent with 1.5 °C global warming

NASA Astrophysics Data System (ADS)

Tokarska, Katarzyna B.; Gillett, Nathan P.

2018-04-01

The Paris Agreement1 commits ratifying parties to pursue efforts to limit the global temperature increase to 1.5 °C relative to pre-industrial levels. Carbon budgets2-5 consistent with remaining below 1.5 °C warming, reported in the IPCC Fifth Assessment Report (AR5)2,6,8, are directly based on Earth system model (Coupled Model Intercomparison Project Phase 5)7 responses, which, on average, warm more than observations in response to historical CO2 emissions and other forcings8,9. These models indicate a median remaining budget of 55 PgC (ref. 10, base period: year 1870) left to emit from January 2016, the equivalent to approximately five years of emissions at the 2015 rate11,12. Here we calculate warming and carbon budgets relative to the decade 2006-2015, which eliminates model-observation differences in the climate-carbon response over the historical period9, and increases the median remaining carbon budget to 208 PgC (33-66% range of 130-255 PgC) from January 2016 (with mean warming of 0.89 °C for 2006-2015 relative to 1861-188013-18). There is little sensitivity to the observational data set used to infer warming that has occurred, and no significant dependence on the choice of emissions scenario. Thus, although limiting median projected global warming to below 1.5 °C is undoubtedly challenging19-21, our results indicate it is not impossible, as might be inferred from the IPCC AR5 carbon budgets2,8.

Global estimations of the inventory and mitigation potential of methane emissions from rice cultivation conducted using the 2006 Intergovernmental Panel on Climate Change Guidelines

NASA Astrophysics Data System (ADS)

Yan, Xiaoyuan; Akiyama, Hiroko; Yagi, Kazuyuki; Akimoto, Hajime

2009-06-01

The Intergovernmental Panel on Climate Change (IPCC) regularly publishes guidelines for national greenhouse gas inventories and methane emission (CH4) from rice paddies has been an important component of these guidelines. While there have been many estimates of global CH4 emissions from rice fields, none of them have been obtained using the IPCC guidelines. Therefore, we used the Tier 1 method described in the 2006 IPCC guidelines to estimate the global CH4 emissions from rice fields. To accomplish this, we used country-specific statistical data regarding rice harvest areas and expert estimates of relevant agricultural activities. The estimated global emission for 2000 was 25.6 Tg a-1, which is at the lower end of earlier estimates and close to the total emission summarized by individual national communications. Monte Carlo simulation revealed a 95% uncertainty range of 14.8-41.7 Tg a-1; however, the estimation uncertainty was found to depend on the reliability of the information available regarding the amount of organic amendments and the area of rice fields that were under continuous flooding. We estimated that if all of the continuously flooded rice fields were drained at least once during the growing season, the CH4 emissions would be reduced by 4.1 Tg a-1. Furthermore, we estimated that applying rice straw off season wherever and whenever possible would result in a further reduction in emissions of 4.1 Tg a-1 globally. Finally, if both of these mitigation options were adopted, the global CH4 emission from rice paddies could be reduced by 7.6 Tg a-1. Although draining continuously flooded rice fields may lead to an increase in nitrous oxide (N2O) emission, the global warming potential resulting from this increase is negligible when compared to the reduction in global warming potential that would result from the CH4 reduction associated with draining the fields.

Scientists' views about attribution of global warming.

PubMed

Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

2014-08-19

Results are presented from a survey held among 1868 scientists studying various aspects of climate change, including physical climate, climate impacts, and mitigation. The survey was unique in its size, broadness and level of detail. Consistent with other research, we found that, as the level of expertise in climate science grew, so too did the level of agreement on anthropogenic causation. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), explicitly agreed with anthropogenic greenhouse gases (GHGs) being the dominant driver of recent global warming. The respondents' quantitative estimate of the GHG contribution appeared to strongly depend on their judgment or knowledge of the cooling effect of aerosols. The phrasing of the IPCC attribution statement in its fourth assessment report (AR4)-providing a lower limit for the isolated GHG contribution-may have led to an underestimation of the GHG influence on recent warming. The phrasing was improved in AR5. We also report on the respondents' views on other factors contributing to global warming; of these Land Use and Land Cover Change (LULCC) was considered the most important. Respondents who characterized human influence on climate as insignificant, reported having had the most frequent media coverage regarding their views on climate change.

Ischemia-induced glomerular parietal epithelial cells hyperplasia: Commonly misdiagnosed cellular crescent in renal biopsy.

PubMed

Zeng, Yeting; Wang, Xinrui; Xie, Feilai; Zheng, Zhiyong

2017-08-01

Ischemic pseudo-cellular crescent (IPCC) that is induced by ischemia and composed of hyperplastic glomerular parietal epithelial cells resembles cellular crescent. In this study, we aimed to assess the clinical and pathological features of IPCC in renal biopsy to avoid over-diagnosis and to determine the diagnostic basis. 4 IPCC cases diagnosed over a 4-year period (2012-2015) were evaluated for the study. Meanwhile, 5 cases of ANCA-associated glomerulonephritis and 5 cases of lupus nephritis (LN) were selected as control. Appropriate clinical data, morphology, and immunohistochemical features of all cases were retrieved. Results showed that the basement membrane of glomerulus with IPCC appeared as a concentric twisted ball, and glomerular cells of the lesion were reduced even entirely absent, and the adjacent afferent arterioles showed sclerosis or luminal stenosis. Furthermore, immune globulin deposition, vasculitis, and fibrinous exudate have not been observed in IPCC. While the cellular crescents showed diverse characteristics in both morphology and immunostaining in the control group. Therefore, these results indicated that IPCC is a sort of ischemic reactive hyperplasia and associated with sclerosis, stenosis, or obstruction of adjacent afferent arterioles, which is clearly different from cellular crescents result from glomerulonephritis. Copyright © 2017 Elsevier GmbH. All rights reserved.

Assessing the near-term risk of climate uncertainty : interdependencies among the U.S. states.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loose, Verne W.; Lowry, Thomas Stephen; Malczynski, Leonard A.

2010-04-01

Policy makers will most likely need to make decisions about climate policy before climate scientists have resolved all relevant uncertainties about the impacts of climate change. This study demonstrates a risk-assessment methodology for evaluating uncertain future climatic conditions. We estimate the impacts of climate change on U.S. state- and national-level economic activity from 2010 to 2050. To understand the implications of uncertainty on risk and to provide a near-term rationale for policy interventions to mitigate the course of climate change, we focus on precipitation, one of the most uncertain aspects of future climate change. We use results of the climate-modelmore » ensemble from the Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report 4 (AR4) as a proxy for representing climate uncertainty over the next 40 years, map the simulated weather from the climate models hydrologically to the county level to determine the physical consequences on economic activity at the state level, and perform a detailed 70-industry analysis of economic impacts among the interacting lower-48 states. We determine the industry-level contribution to the gross domestic product and employment impacts at the state level, as well as interstate population migration, effects on personal income, and consequences for the U.S. trade balance. We show that the mean or average risk of damage to the U.S. economy from climate change, at the national level, is on the order of $1 trillion over the next 40 years, with losses in employment equivalent to nearly 7 million full-time jobs.« less

Downscale climate change scenarios over the Western Himalayan region of India using multi-generation CMIP experiments

NASA Astrophysics Data System (ADS)

Das, Lalu; Meher, Jitendra K.; Akhter, Javed

2017-04-01

Assessing climate change information over the Western Himalayan Region (WHR) of India is crucial but challenging task due to its limited numbers of station data containing huge missing values. The issues of missing values of station data were replaced the Multiple Imputation Chained Equation (MICE) technique. Finally 22 numbers of rain gauge stations having continuous data during 1901-2005 and 16 numbers stations having continuous temperature data during 1969-2009 were considered as " reference stations for assessing rainfall and temperature trends in addition to evaluation of the GCMs available in the Coupled Model Intercomparison Project, Phase 3 (CMIP3) and phase 5 (CMIP5) over WRH. Station data indicates that the winter warming is higher and rapid (1.05oC) than other seasons and less warming in the post monsoon season in the last 41 years. Area averaged using 22 station data indicates that monsoon and winter rainfall has decreased by -5 mm and -320 mm during 1901-2000 while pre-monsoon and post monsoon showed an increasing trends of 21 mm and 13 mm respectively. Present study is constructed the downscaled climate change information at station locations (22 and 16 stations for rainfall and temperature respectively) over the WHR from the GCMs commonly available in the IPCC's different generations assessment reports namely 2nd, 3rd, 4th and 5th thereafter known as SAR, TAR, AR4 and AR5 respectively. Once the downscaled results are obtained for each generation model outputs, then a comparison of studies is carried out from the results of each generation. Finally an overall model improvement index (OMII) is developed using the downscaling results which is used to investigate the model improvement across generations as well as the improvement of downscaling results obtained from the empirical statistical downscaling (ESD) methods. In general, the results indicate that there is a gradual improvement of GCMs simulations as well as downscaling results across generation. Key words: MICE Techniques, CMIP3, CMIP5, ESD and OMII

The FAOSTAT Emissions database for AFOLU: Updates for 1961-2015

NASA Astrophysics Data System (ADS)

Tubiello, F.

2017-12-01

The FAO computes GHG emissions for agriculture and land use since 2012. Data are disseminate in FAOSTAT, with country detail and global coverage, based on IPCC 2006 Tier 1 and underlying FAOSTAT activity data, complemented by use of geospatial maps for specific land use/land cover dynamics. Methods for capacity development with countries based on teh FAOSTAT approach are discussed in the context of suporting the enhanced transprency framework of teh Paris agreement. New updates to 2015 are discussed, including findings on peat emissions and initial projections of land use emissions to 2030 for south east asia. It is found that, by considering the time dynamics of land use change in Indonesia relative to palm oil cultivation, result in a doubling of the earlier estimates of emissions from drained organic soils that had informed the IPCC AR5. The 2030 projections show that, within a scenario approach, teh bulk of AFOLU emissoins increase in south east asia is also linked primarily to palm oil dynamics, with a diminishing impact towards 2030 due to markeyt dynamics.

Population exposure to heat-related extremes: Demographic change vs climate change

NASA Astrophysics Data System (ADS)

Jones, B.; O'Neill, B. C.; Tebaldi, C.; Oleson, K. W.

2014-12-01

Extreme heat events are projected to increase in frequency and intensity in the coming decades [1]. The physical effects of extreme heat on human populations are well-documented, and anticipating changes in future exposure to extreme heat is a key component of adequate planning/mitigation [2, 3]. Exposure to extreme heat depends not only on changing climate, but also on changes in the size and spatial distribution of the human population. Here we focus on systematically quantifying exposure to extreme heat as a function of both climate and population change. We compare exposure outcomes across multiple global climate and spatial population scenarios, and characterize the relative contributions of each to population exposure to extreme heat. We consider a 2 x 2 matrix of climate and population output, using projections of heat extremes corresponding to RCP 4.5 and RCP 8.5 from the NCAR community land model, and spatial population projections for SSP 3 and SSP 5 from the NCAR spatial population downscaling model. Our primary comparison is across RCPs - exposure outcomes from RCP 4.5 versus RCP 8.5 - paying particular attention to how variation depends on the choice of SSP in terms of aggregate global and regional exposure, as well as the spatial distribution of exposure. We assess how aggregate exposure changes based on the choice of SSP, and which driver is more important, population or climate change (i.e. does that outcome vary more as a result of RCP or SSP). We further decompose the population component to analyze the contributions of total population change, migration, and changes in local spatial structure. Preliminary results from a similar study of the US suggests a four-to-six fold increase in total exposure by the latter half of the 21st century. Changes in population are as important as changes in climate in driving this outcome, and there is regional variation in the relative importance of each. Aggregate population growth, as well as redistribution of the population across larger US regions, strongly affects outcomes while smaller-scale spatial patterns of population change have smaller effects. [1] Collins, M. et al. (2013) Contribution of WG I to the 5th AR of the IPCC[2] Romero-Lankao, P. et al (2014) Contribution of WG II to the 5th AR of the IPCC[3] Walsh, J. et al. (2014) The 3rd National Climate Assessment

Preoptimised VB: a fast method for the ground and excited states of ionic clusters II. Delocalised preoptimisation for He 2+, Ar 2+, He 3+ and Ar 3+

NASA Astrophysics Data System (ADS)

Archirel, Pierre

1997-09-01

We generalise the preoptimisation of orbitals within VB (Part I of this series) through letting the orbitals delocalise on the neighbouring fragments. The method is more accurate than the local preoptimisation. The method is tested on the rare gas clusters He 2+, Ar 2+, He 3+ and Ar 3+. The results are in good agreement with previously published data on these systems. We complete these data with higher excited states. The binding energies of (ArCO) +, (ArN 2) + and N 4+ are revisited. The simulation of the SCF method is extended to Cu +H 2O.

Rainwater harvesting possibility under climate change: A basin-scale case study over western province of Saudi Arabia

NASA Astrophysics Data System (ADS)

Almazroui, Mansour; Islam, M. Nazrul; Balkhair, Khaled S.; Şen, Zekâi; Masood, Amjad

2017-06-01

Groundwater reservoirs are important water resources all over the world. Especially, they are of utmost significance for arid and semi-arid regions, and therefore, a sustainable exploitation of these reservoirs needs to be ensured. The natural and most exclusive water supplier to groundwater reservoirs in Saudi Arabia is rainfall, which is characterized by sporadic and random temporal and spatial distributions, particularly under the impacts of climate change; giving rise to uncertainty in groundwater recharge quantification. Although in Saudi Arabia, intense and frequent rainfall events are rare, but they generate significant flash floods with huge amounts of surface water. Under such circumstances, any simple but effective water storage augmentation facility such as rainwater harvesting (RWH) structures gain vital importance for sustainability of water supply and survivals in arid and semi-arid regions. The objective of this study is to explore the possibility of RWH over a basin in the western province of Saudi Arabia called Wadi Al-Lith under climate change. Climatic data is obtained from the IPCC AR5 GCMs, which is further downscaled using a regional climate model RegCM4 for the Arabian Peninsula domain. The RegCM4 is driven to simulate climatic parameters including rainfall at 25 km grid resolution for the present climate (1971-2000), and future climate (2006-2099) with representative concentration pathways, RCP4.5 and RCP8.5. Results indicate that more durable and longer wet durations are expected with increasing surplus rainfall amounts in the far future because of climate change impacts. Consequently, future climate scenarios are expected to enhance floods and flash floods occurrences, which call for progressive measures to harness the RWH opportunity.

Exploration of the association rules mining technique for the signal detection of adverse drug events in spontaneous reporting systems.

PubMed

Wang, Chao; Guo, Xiao-Jing; Xu, Jin-Fang; Wu, Cheng; Sun, Ya-Lin; Ye, Xiao-Fei; Qian, Wei; Ma, Xiu-Qiang; Du, Wen-Min; He, Jia

2012-01-01

The detection of signals of adverse drug events (ADEs) has increased because of the use of data mining algorithms in spontaneous reporting systems (SRSs). However, different data mining algorithms have different traits and conditions for application. The objective of our study was to explore the application of association rule (AR) mining in ADE signal detection and to compare its performance with that of other algorithms. Monte Carlo simulation was applied to generate drug-ADE reports randomly according to the characteristics of SRS datasets. Thousand simulated datasets were mined by AR and other algorithms. On average, 108,337 reports were generated by the Monte Carlo simulation. Based on the predefined criterion that 10% of the drug-ADE combinations were true signals, with RR equaling to 10, 4.9, 1.5, and 1.2, AR detected, on average, 284 suspected associations with a minimum support of 3 and a minimum lift of 1.2. The area under the receiver operating characteristic (ROC) curve of the AR was 0.788, which was equivalent to that shown for other algorithms. Additionally, AR was applied to reports submitted to the Shanghai SRS in 2009. Five hundred seventy combinations were detected using AR from 24,297 SRS reports, and they were compared with recognized ADEs identified by clinical experts and various other sources. AR appears to be an effective method for ADE signal detection, both in simulated and real SRS datasets. The limitations of this method exposed in our study, i.e., a non-uniform thresholds setting and redundant rules, require further research.

Preliminary forecasts of Pacific bigeye tuna population trends under the A2 IPCC scenario

NASA Astrophysics Data System (ADS)

Lehodey, P.; Senina, I.; Sibert, J.; Bopp, L.; Calmettes, B.; Hampton, J.; Murtugudde, R.

2010-07-01

An improved version of the spatial ecosystem and population dynamics model SEAPODYM was used to investigate the potential impacts of global warming on tuna populations. The model included an enhanced definition of habitat indices, movements, and accessibility of tuna predators to different vertically migrant and non-migrant micronekton functional groups. The simulations covered the Pacific basin (model domain) at a 2° × 2° geographic resolution. The structure of the model allows an evaluation from multiple data sources, and parameterization can be optimized by adjoint techniques and maximum likelihood using fishing data. A first such optimized parameterization was obtained for bigeye tuna ( Thunnus obesus) in the Pacific Ocean using historical catch data for the last 50 years and a hindcast from a coupled physical-biogeochemical model driven by the NCEP atmospheric reanalysis. The parameterization provided very plausible biological parameter values and a good fit to fishing data from the different fisheries, both within and outside the time period used for optimization. We then employed this model to forecast the future of bigeye tuna populations in the Pacific Ocean. The simulation was driven by the physical-biogeochemical fields predicted from a global marine biogeochemistry - climate simulation. This global simulation was performed with the IPSL climate model version 4 (IPSL-CM4) coupled to the oceanic biogeochemical model PISCES and forced by atmospheric CO 2, from historical records over 1860-2000, and under the SRES A2 IPCC scenario for the 21st century (i.e. atmospheric CO 2 concentration reaching 850 ppm in the year 2100). Potential future changes in distribution and abundance under the IPCC scenario are presented but without taking into account any fishing effort. The simulation showed an improvement in bigeye tuna spawning habitat both in subtropical latitudes and in the eastern tropical Pacific (ETP) where the surface temperature becomes optimal for bigeye tuna spawning. The adult feeding habitat also improved in the ETP due to the increase of dissolved oxygen concentration in the sub-surface allowing adults to access deeper forage. Conversely, in the Western Central Pacific the temperature becomes too warm for bigeye tuna spawning. The decrease in spawning is compensated by an increase of larvae biomass in subtropical regions. However, natural mortality of older stages increased due to lower habitat values (too warm surface temperatures, decreasing oxygen concentration in the sub-surface and less food). This increased mortality and the displacement of surviving fish to the eastern region led to stable then declining adult biomass at the end of the century.

Ligand induced change of β2 adrenergic receptor from active to inactive conformation and its implication for the closed/open state of the water channel: insight from molecular dynamics simulation, free energy calculation and Markov state model analysis.

PubMed

Bai, Qifeng; Pérez-Sánchez, Horacio; Zhang, Yang; Shao, Yonghua; Shi, Danfeng; Liu, Huanxiang; Yao, Xiaojun

2014-08-14

The reported crystal structures of β2 adrenergic receptor (β2AR) reveal that the open and closed states of the water channel are correlated with the inactive and active conformations of β2AR. However, more details about the process by which the water channel states are affected by the active to inactive conformational change of β2AR remain illusive. In this work, molecular dynamics simulations are performed to study the dynamical inactive and active conformational change of β2AR induced by inverse agonist ICI 118,551. Markov state model analysis and free energy calculation are employed to explore the open and close states of the water channel. The simulation results show that inverse agonist ICI 118,551 can induce water channel opening during the conformational transition of β2AR. Markov state model (MSM) analysis proves that the energy contour can be divided into seven states. States S1, S2 and S5, which represent the active conformation of β2AR, show that the water channel is in the closed state, while states S4 and S6, which correspond to the intermediate state conformation of β2AR, indicate the water channel opens gradually. State S7, which represents the inactive structure of β2AR, corresponds to the full open state of the water channel. The opening mechanism of the water channel is involved in the ligand-induced conformational change of β2AR. These results can provide useful information for understanding the opening mechanism of the water channel and will be useful for the rational design of potent inverse agonists of β2AR.

Evaluation of Water Quality Change of Brackish Lake in Snowy Cold Regions Accompanying Climate Change

NASA Astrophysics Data System (ADS)

Kudo, K.; Hasegawa, H.; Nakatsugawa, M.

2017-12-01

This study addresses evaluation of water quality change of brackish lake based on the estimation of hydrological quantities resulting from long-term hydrologic process accompanying climate change. For brackish lakes, such as Lake Abashiri in Eastern Hokkaido, there are concerns about water quality deterioration due to increases in water temperature and salinity. For estimating some hydrological quantities in the Abashiri River basin, including Lake Abashiri, we propose the following methods: 1) MRI-NHRCM20, a regional climate model based on the Representative Concentration Pathways adopted by IPCC AR5, 2) generalized extreme value distribution for correcting bias, 3) kriging adopted variogram for downscaling and 4) Long term Hydrologic Assessment model considering Snow process (LoHAS). In addition, we calculate the discharge from Abashiri River into Lake Abashiri by using estimated hydrological quantities and a tank model, and simulate impacts on water quality of Lake Abashiri due to climate change by setting necessary conditions, including the initial conditions of water temperature and water quality, the pollution load from the inflow rivers, the duration of ice cover and salt pale boundary. The result of the simulation of water quality indicates that climate change is expected to raise the water temperature of the lake surface by approximately 4°C and increase salinity of surface of the lake by approximately 4psu, also if salt pale boundary in the lake raises by approximately 2-m, the concentration of COD, T-N and T-P in the bottom of the lake might increase. The processes leading to these results are likely to be as follows: increased river water flows in along salt pale boundary in lake, causing dynamic flow of surface water; saline bottom water is entrained upward, where it mixes with surface water; and the shear force acting at salt pale boundary helps to increase the supply of salts from bottom saline water to the surface water. In the future, we will conduct similar simulations for a larger area that includes the mouth of Abashiri River. The accuracy of flow field simulation for Lake Abashiri will increase when calculations incorporate the effects of climate change on tide level, water temperature and salinity at the river mouth.

Variability of western Amazon dry-season precipitation extremes: importance of decadal fluctuations and implications for predictability

NASA Astrophysics Data System (ADS)

Fernandes, K.; Baethgen, W.; Verchot, L. V.; Giannini, A.; Pinedo-Vasquez, M.

2014-12-01

A complete assessment of climate change projections requires understanding the combined effects of decadal variability and long-term trends and evaluating the ability of models to simulate them. The western Amazon severe droughts of the 2000s were the result of a modest drying trend enhanced by reduced moisture transport from the tropical Atlantic. Most of the WA dry-season precipitation decadal variability is attributable to decadal fluctuations of the north-south gradient (NSG) in Atlantic sea surface temperature (SST). The observed WA and NSG decadal co-variability is well reproduced in Global Climate Models (GCMs) pre-industrial control (PIC) and historical (HIST) experiments that were part of the Intergovernmental Panel on Climate Change fifth assessment report (IPCC-AR5). This suggests that unforced or natural climate variability, characteristic of the PIC simulations, determines the nature of this coupling, as the results from HIST simulations (forced with greenhouse gases (GHG) and natural and anthropogenic aerosols) are comparable in magnitude and spatial distribution. Decadal fluctuation in the NSG also determines shifts in the probability of repeated droughts and pluvials in WA, as there is a 65% chance of 3 or more years of droughts per decade when NSG>0 compared to 18% when NSG<0. The HIST and PIC model simulations also reproduce the observed shifts in probability distribution of droughts and pluvials as a function of the NSG decadal phase, suggesting there is great potential for decadal predictability based on GCMs. Persistence of the current NSG positive phase may lead to continuing above normal frequencies of western Amazon dry-season droughts.

Global Trends and Variability in Integrated Water Vapor from Ground-Based GPS Data and Climate Models

NASA Astrophysics Data System (ADS)

Bock, O.; Parracho, A. C.; Bastin, S.; Hourdin, F.

2016-12-01

A high-quality, consistent, global, long-term dataset of integrated water vapor (IWV) was produced from Global Positioning System (GPS) measurements at more than 400 sites over the globe among which 120 sites have more than 15 years of data. The GPS delay data were converted to IWV using surface pressure and weighted mean temperature estimates from ERA-Interim reanalysis. A two-step screening method was developed to detect and remove outliers in the IWV data. It is based on: 1) GPS data processing information and delay formal errors, and 2) inter-comparison with ERA-Interim reanalysis data. The GPS IWV data are also homogenized to correct for offsets due to instrumental changes and other unknown factors. The differential homogenization method uses ERA-Interim IWV as a reference. The resulting GPS data are used to document the mean distribution, the global trends and the variability of IWV over the period 1995-2010, and to assess global climate model simulations extracted from the IPCC AR5 archive. Large coherent spatial patterns of moistening and drying are evidenced but significant discrepancies are also seen between GPS measurements, reanalysis and climate models in various regions. In terms of variability, the monthly mean anomalies are inter-compared. The temporal correlation between GPS and the climate model simulations is overall quite small but the spatial variation of the magnitude of the anomalies is globally well simulated. GPS IWV data prove to be useful to validate global climate model simulations and highlight deficiencies in their representation of the water cycle.

Investigation of polar mesocyclones in Arctic Ocean using COSMO-CLM and WRF numerical models and remote sensing data

NASA Astrophysics Data System (ADS)

Varentsov, Mikhail; Verezemskaya, Polina; Baranyuk, Anastasia; Zabolotskikh, Elizaveta; Repina, Irina

2015-04-01

Polar lows (PL), high latitude marine mesoscale cyclones, are an enigmatic atmospheric phenomenon, which could result in windstorm damage of shipping and infrastructure in high latitudes. Because of their small spatial scales, short life times and their tendency to develop in remote data sparse regions (Zahn, Strorch, 2008), our knowledge of their behavior and climatology lags behind that of synoptic-scale cyclones. In case of continuing global warming (IPCC, 2013) and prospects of the intensification of economic activity and marine traffic in Arctic region, the problem of relevant simulation of this phenomenon by numerical models of the atmosphere, which could be used for weather and climate prediction, is especially important. The focus of this paper is researching the ability to simulate polar lows by two modern nonhydrostatic mesoscale numerical models, driven by realistic lateral boundary conditions from ERA-Interim reanalysis: regional climate model COSMO-CLM (Böhm et. al., 2009) and weather prediction and research model (WRF). Fields of wind, pressure and cloudiness, simulated by models, were compared with remote sensing data and ground meteorological observations for several cases, when polar lows were observed, in Norwegian, Kara and Laptev seas. Several types of satellite data were used: atmospheric water vapor, cloud liquid water content and surface wind fields were resampled by examining AMSR-E and AMSR-2 microwave radiometer data (MODIS Aqua, GCOM-W1), and wind fields were additionally extracted from QuickSCAT scatterometer. Infrared and visible pictures of cloud cover were obtained from MODIS (Aqua). Completed comparison shown that COSMO-CLM and WRF models could successfully reproduce evolution of polar lows and their most important characteristics such as size and wind speed in short experiments with WRF model and longer (up to half-year) experiments with COSMO-CLM model. Improvement of the quality of polar lows reproduction by these models in relation to source reanalysis fields were investigated. References: 1. Böhm U. et al. CLM - the climate version of LM: Brief description and long-term applications [Journal] // COSMO Newsletter. - 2006. - Vol. 6. 2. IPCC Fifth Assessment Report: Climate Change 2013 (AR5) Rep.,Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 3. Zahn, M., and H. von Storch (2008), A long-term climatology of North Atlantic polar lows, Geophys. Res. Lett., 35, L22702

Selectivity trend of gas separation through nanoporous graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Hongjun; Chen, Zhongfang; Dai, Sheng

2015-04-15

By means of molecular dynamics (MD) simulations, we demonstrate that porous graphene can efficiently separate gases according to their molecular sizes. The flux sequence from the classical MD simulation is H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4}, which generally follows the trend in the kinetic diameters. This trend is also confirmed from the fluxes based on the computed free energy barriers for gas permeation using the umbrella sampling method and kinetic theory of gases. Both brute-force MD simulations and free-energy calcualtions lead to the flux trend consistent with experiments. Case studies of two compositions of CO{sub 2}/N{sub 2} mixtures further demonstrate themore » separation capability of nanoporous graphene. - Graphical abstract: Classical molecular dynamics simulations show the flux trend of H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4} for their permeation through a porous graphene, in excellent agreement with a recent experiment. - Highlights: • Classical MD simulations show the flux trend of H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4} for their permeation through a porous graphene. • Free energy calculations yield permeation barriers for those gases. • Selectivities for several gas pairs are estimated from the free-energy barriers and the kinetic theory of gases. • The selectivity trend is in excellent agreement with a recent experiment.« less

The Role of Atmospheric Deposition on the Input of Trace Elements to the Surface Ocean: the Bermuda Wet and Dry Record

NASA Astrophysics Data System (ADS)

Church, T. M.; Sedwick, P. N.; Sholkovitz, E. R.

2011-12-01

Global surface temperature variations and changes result from intricate interplay of phenomena varying on scales ranging from fraction of seconds (turbulence) to thousands of years (e.g. glaciations). To complicate these issues further, the contribution of the anthropogenic forcing on the observed changes in surface temperatures varies over time and is spatially non-uniform. While evaluating all individual bands of this broad spectrum is virtually impossible, the availability of global daily datasets in the last few decades from reanalyses and Global Climate Models (GCMs) simulations allows estimating the contribution of phenomena varying on synoptic-to-interannual timescales. Previous studies using GCM simulations for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (IPCC AR4) have documented a consistent poleward shift in the storm tracks related to changes in baroclinicity resulting from global warming. However, our recent research (Cannon et al. 2013) indicated that the pattern of changes in the storm tracks observed in the last few decades is much more complex in both space and time. Complex terrain and the relative distribution of continents, oceans and icecaps play a significant role for changes in synoptic activity. Coupled modes such as the Northern and Southern annular modes, the El Nino-Southern Oscillation (ENSO) and respective teleconnections with changes in baroclinicity have been identified as relevant dynamical forcings for variations of the midlatitude storm tracks, increasing the uncertainties in future projections. Moreover, global warming has modified the amplitude of the annual cycles of temperature, moisture and circulation throughout the planet and there is strong indication that these changes have mostly affected the tropics and Polar Regions. The present study advances these findings by investigating the 'blue-shift' in the underlying dynamics causing surface temperature anomalies and investigates relationships with low and upper level circulation. This research uses two sources of data: global daily Climate Forecast System Reanalysis (CFSR) (1979- 2010) and the Geophysical Fluid Dynamics Laboratory (GFDL) global daily simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Two sets of simulations are investigated: the Historic and Pi-control runs. Here the term ';blue-shift' is used to indicate long-term increase in the amplitude of the synoptic scale relatively to the annual cycle amplitude derived from wavelet analysis as an analogy to the definition commonly used in physics (i.e., a shift toward shorter wavelengths of the spectral lines). It is shown that the blue-shift has been observed in midlatitudes of some continental areas of the Northern Hemisphere and North Pacific but in relatively higher latitudes in the Southern Hemisphere. Tropical areas and high latitudes of the Northern Hemisphere have experienced opposite trend (red-shift). Moreover, the pattern of the blue and red-shifts exhibits seasonal changes. References: Cannon, F., L. M. V. Carvalho, C. Jones, B. Bookhagen, 2013: Multi-Annual Variations in Winter Westerly Disturbance Activity Affecting the Himalaya. Submitted to Climate Dynamics

The 'Blue-Shift' in midlatitude dynamics in a Changing Climate

NASA Astrophysics Data System (ADS)

Carvalho, L. V.

2013-12-01

Global surface temperature variations and changes result from intricate interplay of phenomena varying on scales ranging from fraction of seconds (turbulence) to thousands of years (e.g. glaciations). To complicate these issues further, the contribution of the anthropogenic forcing on the observed changes in surface temperatures varies over time and is spatially non-uniform. While evaluating all individual bands of this broad spectrum is virtually impossible, the availability of global daily datasets in the last few decades from reanalyses and Global Climate Models (GCMs) simulations allows estimating the contribution of phenomena varying on synoptic-to-interannual timescales. Previous studies using GCM simulations for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (IPCC AR4) have documented a consistent poleward shift in the storm tracks related to changes in baroclinicity resulting from global warming. However, our recent research (Cannon et al. 2013) indicated that the pattern of changes in the storm tracks observed in the last few decades is much more complex in both space and time. Complex terrain and the relative distribution of continents, oceans and icecaps play a significant role for changes in synoptic activity. Coupled modes such as the Northern and Southern annular modes, the El Nino-Southern Oscillation (ENSO) and respective teleconnections with changes in baroclinicity have been identified as relevant dynamical forcings for variations of the midlatitude storm tracks, increasing the uncertainties in future projections. Moreover, global warming has modified the amplitude of the annual cycles of temperature, moisture and circulation throughout the planet and there is strong indication that these changes have mostly affected the tropics and Polar Regions. The present study advances these findings by investigating the 'blue-shift' in the underlying dynamics causing surface temperature anomalies and investigates relationships with low and upper level circulation. This research uses two sources of data: global daily Climate Forecast System Reanalysis (CFSR) (1979- 2010) and the Geophysical Fluid Dynamics Laboratory (GFDL) global daily simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Two sets of simulations are investigated: the Historic and Pi-control runs. Here the term ';blue-shift' is used to indicate long-term increase in the amplitude of the synoptic scale relatively to the annual cycle amplitude derived from wavelet analysis as an analogy to the definition commonly used in physics (i.e., a shift toward shorter wavelengths of the spectral lines). It is shown that the blue-shift has been observed in midlatitudes of some continental areas of the Northern Hemisphere and North Pacific but in relatively higher latitudes in the Southern Hemisphere. Tropical areas and high latitudes of the Northern Hemisphere have experienced opposite trend (red-shift). Moreover, the pattern of the blue and red-shifts exhibits seasonal changes. References: Cannon, F., L. M. V. Carvalho, C. Jones, B. Bookhagen, 2013: Multi-Annual Variations in Winter Westerly Disturbance Activity Affecting the Himalaya. Submitted to Climate Dynamics

Insight into runoff characteristics using hydrological modeling in the data-scarce southern Tibetan Plateau: Past, present, and future

PubMed Central

Cai, Mingyong; Yang, Shengtian; Zhao, Changsen; Zhou, Qiuwen; Hou, Lipeng

2017-01-01

Regional hydrological modeling in ungauged regions has attracted growing attention in water resources research. The southern Tibetan Plateau often suffers from data scarcity in watershed hydrological simulation and water resources assessment. This hinders further research characterizing the water cycle and solving international water resource issues in the area. In this study, a multi-spatial data based Distributed Time-Variant Gain Model (MS-DTVGM) is applied to the Yarlung Zangbo River basin, an important international river basin in the southern Tibetan Plateau with limited meteorological data. This model is driven purely by spatial data from multiple sources and is independent of traditional meteorological data. Based on the methods presented in this study, daily snow cover and potential evapotranspiration data in the Yarlung Zangbo River basin in 2050 are obtained. Future (2050) climatic data (precipitation and air temperature) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR5) are used to study the hydrological response to climate change. The result shows that river runoff will increase due to precipitation and air temperature changes by 2050. Few differences are found between daily runoff simulations from different Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5 and RCP8.5) for 2050. Historical station observations (1960–2000) at Nuxia and model simulations for two periods (2006–2009 and 2050) are combined to study inter-annual and intra-annual runoff distribution and variability. The inter-annual runoff variation is stable and the coefficient of variation (CV) varies from 0.21 to 0.27. In contrast, the intra-annual runoff varies significantly with runoff in summer and autumn accounting for more than 80% of the total amount. Compared to the historical period (1960–2000), the present period (2006–2009) has a slightly uneven intra-annual runoff temporal distribution, and becomes more balanced in the future (2050). PMID:28486483

Insight into runoff characteristics using hydrological modeling in the data-scarce southern Tibetan Plateau: Past, present, and future.

PubMed

Cai, Mingyong; Yang, Shengtian; Zhao, Changsen; Zhou, Qiuwen; Hou, Lipeng

2017-01-01

Regional hydrological modeling in ungauged regions has attracted growing attention in water resources research. The southern Tibetan Plateau often suffers from data scarcity in watershed hydrological simulation and water resources assessment. This hinders further research characterizing the water cycle and solving international water resource issues in the area. In this study, a multi-spatial data based Distributed Time-Variant Gain Model (MS-DTVGM) is applied to the Yarlung Zangbo River basin, an important international river basin in the southern Tibetan Plateau with limited meteorological data. This model is driven purely by spatial data from multiple sources and is independent of traditional meteorological data. Based on the methods presented in this study, daily snow cover and potential evapotranspiration data in the Yarlung Zangbo River basin in 2050 are obtained. Future (2050) climatic data (precipitation and air temperature) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR5) are used to study the hydrological response to climate change. The result shows that river runoff will increase due to precipitation and air temperature changes by 2050. Few differences are found between daily runoff simulations from different Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5 and RCP8.5) for 2050. Historical station observations (1960-2000) at Nuxia and model simulations for two periods (2006-2009 and 2050) are combined to study inter-annual and intra-annual runoff distribution and variability. The inter-annual runoff variation is stable and the coefficient of variation (CV) varies from 0.21 to 0.27. In contrast, the intra-annual runoff varies significantly with runoff in summer and autumn accounting for more than 80% of the total amount. Compared to the historical period (1960-2000), the present period (2006-2009) has a slightly uneven intra-annual runoff temporal distribution, and becomes more balanced in the future (2050).

FY 2011 4th Quarter Metric: Estimate of Future Aerosol Direct and Indirect Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koch, D

2011-09-21

The global and annual mean aerosol direct and indirect effects, relative to 1850 conditions, estimated from CESM simulations are 0.02 W m-2 and -0.39 W m-2, respectively, for emissions in year 2100 under the IPCC RCP8.5 scenario. The indirect effect is much smaller than that for 2000 emissions because of much smaller SO2 emissions in 2100; the direct effects are small due to compensation between warming by black carbon and cooling by sulfate.

Numerical Modeling of Flare-productive Active Regions of the Sun

NASA Astrophysics Data System (ADS)

Toriumi, S.; Takasao, S.

2017-12-01

It is known that strong flare events on the Sun take place in active regions (ARs), especially in delta sunspots with closely-packed positive and negative polarities. The delta spots are produced as a result of complex magnetic flux emergence and have strong-field, highly-sheared polarity inversion lines (PILs). Here we report on the numerical simulations of four types of such flare-productive ARs, namely, (1) Spot-Spot, a complex AR with AR-sized PIL, (2) Spot-Satellite, in which a newly-emerging bipole appears next to the pre-existing sunspot, (3) Quadrupole, where two emerging bipoles collide against each other, and (4) Inter-AR, the flares occurring between two separated ARs. We reproduced these four cases by conducting a series of 3D MHD flux emergence simulations and found, for example, that the sheared PILs in these ARs are created through the stretching and advection of horizontal magnetic fields due to relative spot motions. As ARs develop, free magnetic energy becomes stored in the corona, which could be eventually released through flare eruptions. In the presentation, we also mention the relationship between the HMI/SHARP parameters measured in the photosphere and the free energy stored in the corona, and discuss why these parameters successfully predict the flares.

Molecular dynamics simulations of plasma-surface interactions

NASA Astrophysics Data System (ADS)

Vegh, Joseph James

Molecular dynamics (MD) simulations are carried out to examine the fundamental mechanisms of plasma-surface interactions for various systems of interest to the semiconductor industry. These include ion and radical bombardment simulations of silicon, model low-k dielectric materials, and hydrocarbon (HC) based model photoresist materials. Simulations of fluorocarbon (FC), fluorine, and argon ion etching of silicon are conducted to find conditions under which the steady state etch of Si in the presence of a FC surface layer occurs. By varying the FC/F/Ar + ratios over a range of conditions, a correlation between FC layer thickness and Si etch yield (EY) is obtained that agrees qualitatively with experimentally observed trends. Further examination of this system allows for a Si etch mechanism to be proposed. This mechanism is similar to that seen in previous Si etching simulations where FC films do not form. The FC layer is observed to fluctuate in thickness during steady state Si etch, as the result of competition between FC deposition and sputtering of relatively large (> 6 C atoms) FC clusters during Ar+ impacts. This cluster ejection process is seen in all of the systems studied, and the properties of these clusters (composition, size, kinetic energy, etc.) are examined and catalogued. Ar+ and H radical and ion bombardment of a methylated Si surface is simulated as a model of plasma etching of low-k dielectric materials. The mechanisms and product distributions observed for 300 K H radical bombardment agree well with experiment. The etch characteristics of Ar+ bombardment are examined as a function of ion energy, and the corresponding variations in surface structure at high ion fluence are characterized. Various HC polymer surfaces are studied under ion and radical bombardment to examine plasma species interactions with model photoresist materials. Simulations of 100 eV Ar+ bombardment of polystyrene (PS), poly(4-methylstyrene) (P4MS), and poly(alpha-methylstyrene) (PalphaMS) show that for all of these materials (which have similar chemical compositions: PS: (C8H 8)x, PalphaMS and P4MS: (C9H 10)x), a densely crosslinked, dehydrogenated damaged layer forms at high ion fluences that greatly reduces the sputter yield of the material. During the initial transient period of bombardment, PalphaMS shows sputter yields nearly twice as high as P4MS or PS; polymer structure can play a role during the early stages of etch. Both the initial and high fluence etch characteristics match those observed experimentally. Further, fluctuations from cell-to-cell are much higher for the PalphaMS simulations, which may correlate to the increased roughening observed experimentally for PalphaMS. Additional simulations are carried out to examine the effects of H and F radical addition during Ar+ bombardment of PS. Both radical species are shown to inhibit and/or reverse the formation of the dehydrogenated layer that forms during bombardment with Ar+ alone. Further studies examine the effect of inert ion mass through simulations of Ar +, Xe+, and He+ bombardment of PS, amorphous C, and nanoscale features on diamond surfaces. The differences in penetration depth, kinetic energy deposition, and scattering patterns are suggestive of the differing etch characteristics that are seen experimentally for these ions. A discussion of dangling bond formation during ion bombardment and longer time-scale dynamics is also offered. A brief review of currently available potential energy functions is presented. Selected results from MD simulations that utilize some of these potentials and are closely related to the work in this dissertation are also discussed. The difficulties of expanding potential energy functions vis-a-vis commonly used ab initio quantum chemical calculations are also addressed.

Optical and heat transfer performance of a novel non-imaging concentrator

NASA Astrophysics Data System (ADS)

Sellami, Nazmi; Meng, Xian-long; Xia, Xin-Lin; Knox, Andrew R.; Mallick, Tapas K.

2015-09-01

In this study, the Crossed Compound Parabolic Concentrator CCPC is modified to demonstrate for the first time a new generation of solar concentrators working simultaneously as an electricity generator and thermal collector. It is designed to have two complementary surfaces, one reflective and one absorptive, and is called an absorptive/reflective CCPC (AR-CCPC). Usually, the height of the CCPC is truncated with a minor sacrifice of the geometric concentration. These truncated surfaces rather than being eliminated are instead replaced with absorbent surfaces to collect heat from solar radiation. The optical, thermal and total efficiency of the AR-CCPC was simulated and compared for different geometric concentration ratios varying from 3.6x to 4x. It was found that the combined electrical and thermal efficiency of the AR-CCPC 3.6x/4x remains constant and high all day long and the overall efficiency reach up to 94%. In addition, the temperature distributions of AR-CCPC surfaces and the assembled solar cell were simulated based on those heat flux boundary conditions. It shows that the adding of thermal absorbent surface can apparently increase the wall temperature.

Integration and Exposure of Large Scale Computational Resources Across the Earth System Grid Federation (ESGF)

NASA Astrophysics Data System (ADS)

Duffy, D.; Maxwell, T. P.; Doutriaux, C.; Williams, D. N.; Chaudhary, A.; Ames, S.

2015-12-01

As the size of remote sensing observations and model output data grows, the volume of the data has become overwhelming, even to many scientific experts. As societies are forced to better understand, mitigate, and adapt to climate changes, the combination of Earth observation data and global climate model projects is crucial to not only scientists but to policy makers, downstream applications, and even the public. Scientific progress on understanding climate is critically dependent on the availability of a reliable infrastructure that promotes data access, management, and provenance. The Earth System Grid Federation (ESGF) has created such an environment for the Intergovernmental Panel on Climate Change (IPCC). ESGF provides a federated global cyber infrastructure for data access and management of model outputs generated for the IPCC Assessment Reports (AR). The current generation of the ESGF federated grid allows consumers of the data to find and download data with limited capabilities for server-side processing. Since the amount of data for future AR is expected to grow dramatically, ESGF is working on integrating server-side analytics throughout the federation. The ESGF Compute Working Team (CWT) has created a Web Processing Service (WPS) Application Programming Interface (API) to enable access scalable computational resources. The API is the exposure point to high performance computing resources across the federation. Specifically, the API allows users to execute simple operations, such as maximum, minimum, average, and anomalies, on ESGF data without having to download the data. These operations are executed at the ESGF data node site with access to large amounts of parallel computing capabilities. This presentation will highlight the WPS API, its capabilities, provide implementation details, and discuss future developments.

Quantifying loss and damage from anthropogenic climate change - Bridging the gap between two research communities

NASA Astrophysics Data System (ADS)

Otto, F. E. L.

2015-12-01

The science of attribution of meteorological events to anthropogenic causes has for the first time been included in the latest assessment of the Physical Science Basis of the Climate, (WGI), of the Fifth IPCC Assessment Report AR5 (Stocker et al., 2013). At the same time there is a very rapidly growing body of literature on climate change and its impact on economy, society and environment but apart from very few exemptions no link is made to the causes of these changes. Observed changes in hydrological variables, agriculture, biodiversity and the built environment have been attributed to a changing climate, whether these changes are the result of natural variability or external forcings (Cramer et al., 2014). While the research community represented in WGI assesses whether, and to what extent, recent extreme weather events can be attributed to anthropogenic emissions of greenhouse gases and aerosols, the research community of impact specialists asks how climatic changes lead to different impacts largely independent of the causes of such changes. This distinction becomes potentially very relevant with respect to the 2013 established the Warsaw International Mechanism (WIM) to address loss and damage from the impacts of climate change in developing countries under the UNFCCC climate change negotiations. Currently there is no discussion what consists of loss and damage and the reasons for this inexistence of a definition are not primarily scientific but political however, the absence of a definition could potentially lead to absurd consequences if funds in the context of loss and damage would be redistributed, as e.g. suggested, for all low risk high impact events. Here we present the implications of discussed definitions of loss and damage (Huggel et al. 2015) and how scientific evidence could be included. Cramer et al. (2014) Detection and Attribution of Observed Impacts. In: Climate Change 2014: Impacts, Adaptation and Vulnerability Contribution of WG 2 to AR5 of the IPCC. Huggel, C., Stone, D., Eicken, H., & Hansen, G. (2015). Potential and limitations of the attribution of climate change impacts for informing loss and damage discussions and policies. Clim. Change, doi: 10.1007/s10584-015-1441-z. Stocker et al. (eds.) (2013) The IPCC Fifth Assessment Report: The Physical Science Basis. Cambridge University Press.

Augmented reality intravenous injection simulator based 3D medical imaging for veterinary medicine.

PubMed

Lee, S; Lee, J; Lee, A; Park, N; Lee, S; Song, S; Seo, A; Lee, H; Kim, J-I; Eom, K

2013-05-01

Augmented reality (AR) is a technology which enables users to see the real world, with virtual objects superimposed upon or composited with it. AR simulators have been developed and used in human medicine, but not in veterinary medicine. The aim of this study was to develop an AR intravenous (IV) injection simulator to train veterinary and pre-veterinary students to perform canine venipuncture. Computed tomographic (CT) images of a beagle dog were scanned using a 64-channel multidetector. The CT images were transformed into volumetric data sets using an image segmentation method and were converted into a stereolithography format for creating 3D models. An AR-based interface was developed for an AR simulator for IV injection. Veterinary and pre-veterinary student volunteers were randomly assigned to an AR-trained group or a control group trained using more traditional methods (n = 20/group; n = 8 pre-veterinary students and n = 12 veterinary students in each group) and their proficiency at IV injection technique in live dogs was assessed after training was completed. Students were also asked to complete a questionnaire which was administered after using the simulator. The group that was trained using an AR simulator were more proficient at IV injection technique using real dogs than the control group (P ≤ 0.01). The students agreed that they learned the IV injection technique through the AR simulator. Although the system used in this study needs to be modified before it can be adopted for veterinary educational use, AR simulation has been shown to be a very effective tool for training medical personnel. Using the technology reported here, veterinary AR simulators could be developed for future use in veterinary education. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

The Earth System Grid Federation: An Open Infrastructure for Access to Distributed Geospatial Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ananthakrishnan, Rachana; Bell, Gavin; Cinquini, Luca

2013-01-01

The Earth System Grid Federation (ESGF) is a multi-agency, international collaboration that aims at developing the software infrastructure needed to facilitate and empower the study of climate change on a global scale. The ESGF s architecture employs a system of geographically distributed peer nodes, which are independently administered yet united by the adoption of common federation protocols and application programming interfaces (APIs). The cornerstones of its interoperability are the peer-to-peer messaging that is continuously exchanged among all nodes in the federation; a shared architecture and API for search and discovery; and a security infrastructure based on industry standards (OpenID, SSL,more » GSI and SAML). The ESGF software is developed collaboratively across institutional boundaries and made available to the community as open source. It has now been adopted by multiple Earth science projects and allows access to petabytes of geophysical data, including the entire model output used for the next international assessment report on climate change (IPCC-AR5) and a suite of satellite observations (obs4MIPs) and reanalysis data sets (ANA4MIPs).« less

The Earth System Grid Federation: An Open Infrastructure for Access to Distributed Geo-Spatial Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cinquini, Luca; Crichton, Daniel; Miller, Neill

2012-01-01

The Earth System Grid Federation (ESGF) is a multi-agency, international collaboration that aims at developing the software infrastructure needed to facilitate and empower the study of climate change on a global scale. The ESGF s architecture employs a system of geographically distributed peer nodes, which are independently administered yet united by the adoption of common federation protocols and application programming interfaces (APIs). The cornerstones of its interoperability are the peer-to-peer messaging that is continuously exchanged among all nodes in the federation; a shared architecture and API for search and discovery; and a security infrastructure based on industry standards (OpenID, SSL,more » GSI and SAML). The ESGF software is developed collaboratively across institutional boundaries and made available to the community as open source. It has now been adopted by multiple Earth science projects and allows access to petabytes of geophysical data, including the entire model output used for the next international assessment report on climate change (IPCC-AR5) and a suite of satellite observations (obs4MIPs) and reanalysis data sets (ANA4MIPs).« less

The Earth System Grid Federation : an Open Infrastructure for Access to Distributed Geospatial Data

NASA Technical Reports Server (NTRS)

Cinquini, Luca; Crichton, Daniel; Mattmann, Chris; Harney, John; Shipman, Galen; Wang, Feiyi; Ananthakrishnan, Rachana; Miller, Neill; Denvil, Sebastian; Morgan, Mark;

Response surface methodological approach for the decolorization of simulated dye effluent using Aspergillus fumigatus fresenius.

PubMed

Sharma, Praveen; Singh, Lakhvinder; Dilbaghi, Neeraj

2009-01-30

The aim of our research was to study, effect of temperature, pH and initial dye concentration on decolorization of diazo dye Acid Red 151 (AR 151) from simulated dye solution using a fungal isolate Aspergillus fumigatus fresenius have been investigated. The central composite design matrix and response surface methodology (RSM) have been applied to design the experiments to evaluate the interactive effects of three most important operating variables: temperature (25-35 degrees C), pH (4.0-7.0), and initial dye concentration (100-200 mg/L) on the biodegradation of AR 151. The total 20 experiments were conducted in the present study towards the construction of a quadratic model. Very high regression coefficient between the variables and the response (R(2)=0.9934) indicated excellent evaluation of experimental data by second-order polynomial regression model. The RSM indicated that initial dye concentration of 150 mg/L, pH 5.5 and a temperature of 30 degrees C were optimal for maximum % decolorization of AR 151 in simulated dye solution, and 84.8% decolorization of AR 151 was observed at optimum growth conditions.

iPcc: a novel feature extraction method for accurate disease class discovery and prediction

PubMed Central

Ren, Xianwen; Wang, Yong; Zhang, Xiang-Sun; Jin, Qi

2013-01-01

Gene expression profiling has gradually become a routine procedure for disease diagnosis and classification. In the past decade, many computational methods have been proposed, resulting in great improvements on various levels, including feature selection and algorithms for classification and clustering. In this study, we present iPcc, a novel method from the feature extraction perspective to further propel gene expression profiling technologies from bench to bedside. We define ‘correlation feature space’ for samples based on the gene expression profiles by iterative employment of Pearson’s correlation coefficient. Numerical experiments on both simulated and real gene expression data sets demonstrate that iPcc can greatly highlight the latent patterns underlying noisy gene expression data and thus greatly improve the robustness and accuracy of the algorithms currently available for disease diagnosis and classification based on gene expression profiles. PMID:23761440

Design and development of multilayer wideband antireflection coating and its annealing study

NASA Astrophysics Data System (ADS)

Jena, S.; Tokas, R. B.; Udupa, D. V.; Thakur, S.; Sahoo, N. K.

2018-04-01

Reflection loss occurs at the glass-air interface, limits performance of many optical devices such as eyeglass, camera lenses, and photovoltaic solar cells. Antireflection (AR) coating on the glass reduces the reflection loss and improves efficiency of such devices. In this paper, wideband AR coating in the visible region has been designed and developed using ZrO2-MgO/SiO2 multilayer. The thicknesses of individual thin layers are numerically optimized to get maximum transmission of the visible light. The optimized four thin layers have been deposited on BK7 glass substrate using electron beam evaporation technique. The measured transmission spectrum of the 4-layer AR coating is compared with that of simulated spectrum. The transmission of the single side AR coating increases by more than 3% as compared to that of bare glass substrate in the wavelength region of 470 nm - 810 nm. The wideband AR coating has been annealed at 200°C for 4 hours in ambient condition. The transmission of the AR coating decreases after the annealing, resulting degradation in its wideband AR characteristics.

Structural Diversity of Ligand-Binding Androgen Receptors Revealed by Microsecond Long Molecular Dynamics Simulations and Enhanced Sampling.

PubMed

Duan, Mojie; Liu, Na; Zhou, Wenfang; Li, Dan; Yang, Minghui; Hou, Tingjun

2016-09-13

Androgen receptor (AR) plays important roles in the development of prostate cancer (PCa). The antagonistic drugs, which suppress the activity of AR, are widely used in the treatment of PCa. However, the molecular mechanism of antagonism about how ligands affect the structures of AR remains elusive. To better understand the conformational variability of ARs bound with agonists or antagonists, we performed long time unbiased molecular dynamics (MD) simulations and enhanced sampling simulations for the ligand binding domain of AR (AR-LBD) in complex with various ligands. Based on the simulation results, we proposed an allosteric pathway linking ligands and helix 12 (H12) of AR-LBD, which involves the interactions among the ligands and the residues W741, H874, and I899. The interaction pathway provides an atomistic explanation of how ligands affect the structure of AR-LBD. A repositioning of H12 was observed, but it is facilitated by the C-terminal of H12, instead of by the loop between helix 11 (H11) and H12. The bias-exchange metadynamics simulations further demonstrated the above observations. More importantly, the free energy profiles constructed by the enhanced sampling simulations revealed the transition process between the antagonistic form and agonistic form of AR-LBD. Our results would be helpful for the design of more efficient antagonists of AR to combat PCa.

The global warming potential of methane reassessed with combined stratosphere and troposphere chemistry

NASA Astrophysics Data System (ADS)

Holmes, C. D.; Archibald, A. T.; Eastham, S. D.; Søvde, O. A.

2017-12-01

Methane is a direct and indirect greenhouse gas. The direct greenhouse effect comes from the radiation absorbed and emitted by methane itself. The indirect greenhouse effect comes from radiatively active gases that are produced during methane oxidation: principally O3, H2O, and CO2. Methane also suppresses tropospheric OH, which indirectly affects numerous greenhouses gases and aerosols. Traditionally, the methane global warming potential (GWP) has included the indirect effects on tropospheric O3 and OH and stratospheric H2O, with these effects estimated independently from unrelated tropospheric and stratospheric chemistry models and observations. Using this approach the CH4 is about 28 over 100 yr (without carbon cycle feedbacks, IPCC, 2013). Here we present a comprehensive analysis of the CH4 GWP in several 3-D global atmospheric models capable of simulating both tropospheric and stratospheric chemistry (GEOS-Chem, Oslo CTM3, UKCA). This enables us to include, for the first time, the indirect effects of CH4 on stratospheric O3 and stratosphere-troposphere coupling. We diagnose the GWP from paired simulations with and without a 5% perturbation to tropospheric CH4 concentrations. Including stratospheric chemistry nearly doubles the O3 contribution to CH4 GWP because of O3 production in the lower stratosphere and because CH4 inhibits Cl-catalyzed O3 loss in the upper stratosphere. In addition, stratosphere-troposphere coupling strengthens the chemical feedback on its own lifetime. In the stratosphere, this feedback operates by a CH4 perturbation thickening the stratospheric O3 layer, which impedes UV-driven OH production in the troposphere and prolongs the CH4 lifetime. We also quantify the impact of CH4-derived H2O on the stratospheric HOx cycles but these effects are small. Combining all of the above, these models suggest that the 100-yr GWP of CH4 is over 33.5, a 20% increase over the latest IPCC assessment.

Effect of Practice Integration between Urologists and Radiation Oncologists on Prostate Cancer Treatment Patterns

PubMed Central

Bekelman, Justin E.; Suneja, Gita; Guzzo, Thomas; Evan Pollack, Craig; Armstrong, Katrina; Epstein, Andrew J.

2013-01-01

Purpose National attention has focused on whether urology-radiation oncology practice integration – known as integrated prostate cancer centers (IPCCs) – contributes to use of intensity-modulated radiation therapy (IMRT), a common and expensive treatment for prostate cancer. Methods We examined prostate cancer treatment patterns pre- and post-conversion of a urology practice to an IPCC in July, 2006. Using the SEER-Medicare database, we identified patients age ≥ 65 years diagnosed in one state-wide registry with non-metastatic prostate cancer between 2004 and 2007 and classified patients into 3 groups: (1) those seen by IPCC physicians (exposure group); (2) those living in the same hospital referral region (HRR) and not seen by IPCC physicians (HRR-control group); and (3) those living elsewhere in the state (state-control group). We compared changes in treatment among the 3 groups, adjusting for patient, clinical, and socio-economic factors. Results Compared with the 8.1 percentage point (ppt) increase in adjusted IMRT use in the state-control group, IMRT increased 20.3 ppts (95% confidence interval [CI] 13.4, 27.1) in the IPCC group and 19.2 ppts (95% CI 9.6, 28.9) in the HRR-control group. Androgen-deprivation therapy (ADT), for which Medicare reimbursement declined sharply, decreased similarly in the IPCC and HRR-control groups. Prostatectomy declined significantly in the IPCC group. Conclusions Coincident with the conversion of a urology group practice to an IPCC, we observed increases in IMRT and decreases in ADT among patients seen by IPCC physicians and those seen in the surrounding healthcare market that were not observed in the remainder of the state. PMID:23399652

Cost-effectiveness of intensive psychiatric community care for high users of inpatient services.

PubMed

Rosenheck, R A; Neale, M S

1998-05-01

This 2-year experimental study evaluated the effectiveness and cost of 10 intensive psychiatric community care (IPCC) programs at Department of Veterans Affairs medical centers in the northeastern United States. High users of inpatient services were randomly assigned to either IPCC or standard Department of Veterans Affairs care at 6 general medical and surgical hospitals (n=271 vs 257) and 4 neuropsychiatric hospitals (n=183 vs 162). Patient interviews every 6 months and national computerized data were used to assess clinical outcomes, health service use, health care costs, and non-health care costs. There was only 1 significant clinical difference between groups across follow-up periods: IPCC patients at general medical and surgical sites had higher community living skills. However, at the final interview, IPCC patients at general medical and surgical sites showed significantly lower symptoms, higher functioning, and greater satisfaction with services. Treatment with IPCC significantly reduced hospital use only at neuropsychiatric sites (320 vs 513 days, P<.001). Total societal costs, including the cost of IPCC, were lower for IPCC at neuropsychiatric sites ($82,454 vs $116,651, P<.001), but greater at general medical and surgical sites ($51,537 vs $46,491, P<.01). When 2 sites that incompletely implemented the model were dropped from the analysis, costs at general medical and surgical sites were $38 lower for IPCC (P=.26). At acute care hospitals, IPCC treatment is associated with greater long-term clinical improvement and, when fully implemented, is cost-neutral. At long-stay hospitals treating older, less-functional patients, it is not associated with clinical or functional improvement but generates substantial cost savings. Intensive psychiatric community care thus has beneficial, but somewhat different, outcome profiles at different types of hospitals.

Robust signals of future projections of Indian summer monsoon rainfall by IPCC AR5 climate models: Role of seasonal cycle and interannual variability

NASA Astrophysics Data System (ADS)

Jayasankar, C. B.; Surendran, Sajani; Rajendran, Kavirajan

2015-05-01

Coupled Model Intercomparison Project phase 5 (Fifth Assessment Report of Intergovernmental Panel on Climate Change) coupled global climate model Representative Concentration Pathway 8.5 simulations are analyzed to derive robust signals of projected changes in Indian summer monsoon rainfall (ISMR) and its variability. Models project clear future temperature increase but diverse changes in ISMR with substantial intermodel spread. Objective measures of interannual variability (IAV) yields nearly equal chance for future increase or decrease. This leads to discrepancy in quantifying changes in ISMR and variability. However, based primarily on the physical association between mean changes in ISMR and its IAV, and objective methods such as k-means clustering with Dunn's validity index, mean seasonal cycle, and reliability ensemble averaging, projections fall into distinct groups. Physically consistent groups of models with the highest reliability project future reduction in the frequency of light rainfall but increase in high to extreme rainfall and thereby future increase in ISMR by 0.74 ± 0.36 mm d-1, along with increased future IAV. These robust estimates of future changes are important for useful impact assessments.

Web based visualization of large climate data sets

USGS Publications Warehouse

Alder, Jay R.; Hostetler, Steven W.

2015-01-01

We have implemented the USGS National Climate Change Viewer (NCCV), which is an easy-to-use web application that displays future projections from global climate models over the United States at the state, county and watershed scales. We incorporate the NASA NEX-DCP30 statistically downscaled temperature and precipitation for 30 global climate models being used in the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and hydrologic variables we simulated using a simple water-balance model. Our application summarizes very large, complex data sets at scales relevant to resource managers and citizens and makes climate-change projection information accessible to users of varying skill levels. Tens of terabytes of high-resolution climate and water-balance data are distilled to compact binary format summary files that are used in the application. To alleviate slow response times under high loads, we developed a map caching technique that reduces the time it takes to generate maps by several orders of magnitude. The reduced access time scales to >500 concurrent users. We provide code examples that demonstrate key aspects of data processing, data exporting/importing and the caching technique used in the NCCV.

Climate uncertainty and implications for U.S. state-level risk assessment through 2050.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loose, Verne W.; Lowry, Thomas Stephen; Malczynski, Leonard A.

2009-10-01

Decisions for climate policy will need to take place in advance of climate science resolving all relevant uncertainties. Further, if the concern of policy is to reduce risk, then the best-estimate of climate change impacts may not be so important as the currently understood uncertainty associated with realizable conditions having high consequence. This study focuses on one of the most uncertain aspects of future climate change - precipitation - to understand the implications of uncertainty on risk and the near-term justification for interventions to mitigate the course of climate change. We show that the mean risk of damage to themore » economy from climate change, at the national level, is on the order of one trillion dollars over the next 40 years, with employment impacts of nearly 7 million labor-years. At a 1% exceedance-probability, the impact is over twice the mean-risk value. Impacts at the level of individual U.S. states are then typically in the multiple tens of billions dollar range with employment losses exceeding hundreds of thousands of labor-years. We used results of the Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report 4 (AR4) climate-model ensemble as the referent for climate uncertainty over the next 40 years, mapped the simulated weather hydrologically to the county level for determining the physical consequence to economic activity at the state level, and then performed a detailed, seventy-industry, analysis of economic impact among the interacting lower-48 states. We determined industry GDP and employment impacts at the state level, as well as interstate population migration, effect on personal income, and the consequences for the U.S. trade balance.« less

Climate Change and Adaptation Planning on the Los Angeles Aqueduct

NASA Astrophysics Data System (ADS)

Roy, S. B.; Bales, R. C.; Costa-Cabral, M. C.; Chen, L.; Maurer, E. P.; Miller, N. L.; Mills, W. B.

2009-12-01

This study provides an assessment of the potential impacts of climate change on the Eastern Sierra Nevada snowpack and snowmelt timing, using a combination of empirical (i.e., data-based) models, and computer simulation models forced by GCM-projected 21st century climatology (IPCC 2007 AR4 projections). Precipitation from the Eastern Sierra Nevada is one of the main water sources for Los Angeles' more than 4 million people - a source whose future availability is critical to the city's growing population and large economy. Precipitation in the region falls mostly in winter and is stored in the large natural reservoir that is the snowpack. Meltwater from the Eastern Sierra is delivered to the city by the 340-mile long Los Angeles Aqueducts. The analysis is focused on the nature of the impact to the LAA water supplies over the 21st century due to potential climate change, including volume of precipitation, the mix of snowfall and rainfall, shifts in the timing of runoff, interannual variability and multi-year droughts. These impacts further affect the adequacy of seasonal and annual carryover water storage, and potentially water treatment. Most of the snow in the 10,000 km^2 Mono-Owens basins that feed the LAA occurs in a relatively narrow, 10-20 km wide, high-elevation band on the steep slopes of 20 smaller basins whose streams drain into the Owens River and thence LAA. Extending over 240 km in the north-south direction, these basins present special challenges for estimating snowpack amounts and downscaling climate-model data. In addition, there are few meteorological stations and snow measurements in the snow-producing parts of the basins to drive physically based hydrologic modeling.

Methane correction factors for estimating emissions from aerobic wastewater treatment facilities based on field data in Mexico and on literature review.

PubMed

Noyola, A; Paredes, M G; Güereca, L P; Molina, L T; Zavala, M

2018-10-15

Wastewater treatment (WWT) may be an important source of methane (CH 4 ), a greenhouse gas with significant global warming potential. Sources of CH 4 emissions from WWT facilities can be found in the water and in the sludge process lines. Among the methodologies for estimating CH 4 emissions inventories from WWT, the more adopted are the guidelines of the Intergovernmental Panel on Climate Change (IPCC), which recommends default emission factors (Tier 1) depending on WWT systems. Recent published results show that well managed treatment facilities may emit CH 4 , due to dissolved CH 4 in the influent wastewater; in addition, biological nutrient removal also will produce this gas in the anaerobic (or anoxic) steps. However, none of these elements is considered in the current IPCC guidelines. The aim of this work is to propose modified (and new) methane correction factors (MCF) regarding the current Tier 1 IPCC guidelines for CH 4 emissions from aerobic treatment systems, with and without anaerobic sludge digesters, focusing on intertropical countries. The modifications are supported on in situ assessment of fugitive CH 4 emissions in two facilities in Mexico and on relevant literature data. In the case of well-managed centralized aerobic treatment plant, a MCF of 0.06 (instead of the current 0.0) is proposed, considering that the assumption of a CH 4 -neutral treatment facility, as established in the IPCC methodology, is not supported. Similarly, a MCF of 0.08 is proposed for biological nutrient removal processes, being a new entry in the guidelines. Finally, a one-step straightforward calculation is proposed for centralized aerobic treatment plants with anaerobic digesters that avoids confusion when selecting the appropriate default MCF based on the Tier 1 IPCC guidelines. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Tropical climate trends inferred from coral δ18O: a comparison of CMIP5 forward-model results with paleoclimatic observations

NASA Astrophysics Data System (ADS)

Thompson, D. M.; Evans, M. N.; Cole, J. E.; Ault, T. R.; Emile-Geay, J.

2011-12-01

The response of the tropical Pacific Ocean to anthropogenic climate change remains highly uncertain, in part because of the disagreement among 20th-century trends derived from observations and coupled general circulation models (CGCMs). We use a model of reef coral oxygen isotopic composition (δ18O) to compare the observational coral network with synthetic corals ('pseudocorals') modeled from CGCM sea-surface temperature (SST) and sea-surface salinity (SSS). When driven with historical data, we found that a linear temperature and salinity driven model for δ18Ocoral was able to capture the spatial and temporal pattern of ENSO and the linear trend observed in 23 Indo-Pacific coral records between 1958 and 1990. However, we found that none of the pseudocoral networks obtained from a subset of 20th-century AR4 CGCM runs reproduced the magnitude of the secular trend, the change in mean state, or the change in ENSO-related variance observed in the coral network from 1890 to 1990 (Thompson et al., 2011). We believe differences between corals and AR4 CGCM simulated pseudocorals arose from uncertainties in the observed coral network or linear bivariate coral model, undersensitivity of AR4 CGCMs to radiative forcing during the 20th century, and/or biases in the simulated AR4 CGCM SSS fields. Here we apply the same approach to an extended temperature and salinity reanalysis product (SODA v2.2.4, 1871-2008) and CMIP 5 historical simulations to further address 20th-century tropical climate trends and assess remaining uncertainties in both the proxies and models. We explore whether model improvements in the tropical Pacific have led to a stronger agreement between simulated and observed tropical climate trends. [Thompson, D. M., T. R. Ault, M. N. Evans, J. E. Cole, and J. Emile-Geay (2011), Comparison of observed and simulated tropical climate trends using a forward model of coral δ18O, Geophys. Res. Lett., 38, L14706, doi:10.1029/2011GL048224.

Representative concentration pathways and mitigation scenarios for nitrous oxide

NASA Astrophysics Data System (ADS)

Davidson, Eric A.

2012-06-01

The challenges of mitigating nitrous oxide (N2O) emissions are substantially different from those for carbon dioxide (CO2) and methane (CH4), because nitrogen (N) is essential for food production, and over 80% of anthropogenic N2O emissions are from the agricultural sector. Here I use a model of emission factors of N2O to demonstrate the magnitude of improvements in agriculture and industrial sectors and changes in dietary habits that would be necessary to match the four representative concentration pathways (RCPs) now being considered in the fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). Stabilizing atmospheric N2O by 2050, consistent with the most aggressive of the RCP mitigation scenarios, would require about 50% reductions in emission factors in all sectors and about a 50% reduction in mean per capita meat consumption in the developed world. Technologies exist to achieve such improved efficiencies, but overcoming social, economic, and political impediments for their adoption and for changes in dietary habits will present large challenges.

Can Arctic sea-ice melt be explained by atmospheric meridional transports? (Invited)

NASA Astrophysics Data System (ADS)

Tjernstrom, M. K.; Graversen, R. G.

2010-12-01

The Arctic summer sea ice is melting away at an alarming rate, and it is now expected that an principally sea-ice free Arctic summer will occur much earlier than projected by the IPCC AR4 models. At the same time Arctic near-surface temperatures are rising at a rate much faster than the global average. The processes responsible for these changes are debated and many claim that local feedbacks, such as the surface albedo feedback, are the main culprits while other argue that remote effects, such as atmospheric circulation changes on synoptic and hemispheric scales, are the most important. We will explore the effects of the meridional transport by synoptic and larger scale atmospheric circulation on recent changes, using reanalysis data. It will be illustarated how this transport can contribute significant amounts of sensible heat, but also of atmospheric moisture such that local cloud feedbacks as well as the direct greenhouse effect of the water vapor contributes significantly to the surface energy balance over the Arctic polar cap.

Augmented reality in gynecologic surgery: evaluation of potential benefits for myomectomy in an experimental uterine model.

PubMed

Bourdel, Nicolas; Collins, Toby; Pizarro, Daniel; Bartoli, Adrien; Da Ines, David; Perreira, Bruno; Canis, Michel

2017-01-01

Augmented Reality (AR) is a technology that can allow a surgeon to see subsurface structures. This works by overlaying information from another modality, such as MRI and fusing it in real time with the endoscopic images. AR has never been developed for a very mobile organ like the uterus and has never been performed for gynecology. Myomas are not always easy to localize in laparoscopic surgery when they do not significantly change the surface of the uterus, or are at multiple locations. To study the accuracy of myoma localization using a new AR system compared to MRI-only localization. Ten residents were asked to localize six myomas (on a uterine model into a laparoscopic box) when either using AR or in conditions that simulate a standard method (only the MRI was available). Myomas were randomly divided in two groups: the control group (MRI only, AR not activated) and the AR group (AR activated). Software was used to automatically measure the distance between the point of contact on the uterine surface and the myoma. We compared these distances to the true shortest distance to obtain accuracy measures. The time taken to perform the task was measured, and an assessment of the complexity was performed. The mean accuracy in the control group was 16.80 mm [0.1-52.2] versus 0.64 mm [0.01-4.71] with AR. In the control group, the mean time to perform the task was 18.68 [6.4-47.1] s compared to 19.6 [3.9-77.5] s with AR. The mean score of difficulty (evaluated for each myoma) was 2.36 [1-4] versus 0.87 [0-4], respectively, for the control and the AR group. We developed an AR system for a very mobile organ. This is the first user study to quantitatively evaluate an AR system for improving a surgical task. In our model, AR improves localization accuracy.

Global trends and variability in integrated water vapour from ground-based GPS data and atmospheric models

NASA Astrophysics Data System (ADS)

Bock, Olivier; Parracho, Ana; Bastin, Sophie; Hourdin, Frededic; Mellul, Lidia

2016-04-01

A high-quality, consistent, global, long-term dataset of integrated water vapour (IWV) was produced from Global Positioning System (GPS) measurements at more than 400 sites over the globe among which 120 sites have more than 15 years of data. The GPS delay data were converted to IWV using surface pressure and weighted mean temperature estimates from ERA-Interim reanalysis. A two-step screening method was developed to detect and remove outliers in the IWV data. It is based on: 1) GPS data processing information and delay formal errors, and 2) intercomparison with ERA-Interim reanalysis data. The GPS IWV data are also homogenized to correct for offsets due to instrumental changes and other unknown factors. The differential homogenization method uses ERA-Interim IWV as a reference. The resulting GPS data are used to document the mean distribution, the global trends and the variability of IWV over the period 1995-2010, and are analysed in coherence with precipitation and surface temperature data (from observations and ERA-Interim reanalysis). These data are also used to assess global climate model simulations extracted from the IPCC AR5 archive. Large coherent spatial patterns of moistening and drying are evidenced but significant discrepancies are also seen between GPS measurements, reanalysis and climate models in various regions. In terms of variability, the monthly mean anomalies are intercompared. The temporal correlation between GPS and the climate model simulations is overall quite small but the spatial variation of the magnitude of the anomalies is globally well simulated. GPS IWV data prove to be useful to validate global climate model simulations and highlight deficiencies in their representation of the water cycle.

Sea level rise from the Greenland Ice Sheet during the Eemian interglacial: Review of previous work with focus on the surface mass balance

NASA Astrophysics Data System (ADS)

Plach, Andreas; Hestnes Nisancioglu, Kerim

2016-04-01

The contribution from the Greenland Ice Sheet (GIS) to the global sea level rise during the Eemian interglacial (about 125,000 year ago) was the focus of many studies in the past. A main reason for the interest in this period is the considerable warmer climate during the Eemian which is often seen as an equivalent for possible future climate conditions. Simulated sea level rise during the Eemian can therefore be used to better understand a possible future sea level rise. The most recent assessment report of the Intergovernmental Panel on Climate Change (IPCC AR5) gives an overview of several studies and discusses the possible implications for a future sea level rise. The report also reveals the big differences between these studies in terms of simulated GIS extent and corresponding sea level rise. The present study gives a more exhaustive review of previous work discussing sea level rise from the GIS during the Eemian interglacial. The smallest extents of the GIS simulated by various authors are shown and summarized. A focus is thereby given to the methods used to calculate the surface mass balance. A hypothesis of the present work is that the varying results of the previous studies can largely be explained due to the various methods used to calculate the surface mass balance. In addition, as a first step for future work, the surface mass balance of the GIS for a proxy-data derived forcing ("index method") and a direct forcing with a General Circulation Model (GCM) are shown and discussed.

Effects of elliptical burner geometry on partially premixed gas jet flames in quiescent surroundings

NASA Astrophysics Data System (ADS)

Baird, Benjamin

This study is the investigation of the effect of elliptical nozzle burner geometry and partial premixing, both 'passive control' methods, on a hydrogen/hydrocarbon flame. Both laminar and turbulent flames for circular, 3:1, and 4:1 aspect ratio (AR) elliptical burners are considered. The amount of air mixed with the fuel is varied from fuel-lean premixed flames to fuel-rich partially premixed flames. The work includes measurements of flame stability, global pollutant emissions, flame radiation, and flame structure for the differing burner types and fuel conditions. Special emphasis is placed on the near-burner region. Experimentally, both conventional (IR absorption, chemiluminecent, and polarographic emission analysis,) and advanced (laser induced fluorescence, planar laser induced fluorescence, Laser Doppler Velocimetry (LDV), Rayleigh scattering) diagnostic techniques are used. Numerically, simulations of 3-dimensional laminar and turbulent reacting flow are conducted. These simulations are run with reduced chemical kinetics and with a Reynolds Stress Model (RSM) for the turbulence modeling. It was found that the laminar flames were similar in appearance and overall flame length for the 3:1 AR elliptical and the circular burner. The laminar 4:1 AR elliptical burner flame split into two sub-flames along the burner major axis. This splitting had the effect of greatly shortening the 4:1 AR elliptical burner flame to have an overall flame length about half of that of the circular and 3:1 AR elliptical burner flames. The length of all three burners flames increased with increasing burner exit equivalence ratio. The blowout velocity for the three burners increased with increase in hydrogen mass fraction of the hydrogen/propane fuel mixture. For the rich premixed flames, the circular burner was the most stable, the 3:1 AR elliptical burner, was the least stable, and the 4:1 AR elliptical burner was intermediate to the two other burners. This order of stability was due to two reasons. The elliptical burners have enhanced turbulence generation that lowers their stability when compared to the circular burner. The 4:1 AR elliptical burner had greater stability due to a greater velocity decay rate and wider OH reaction zones particularly in the region between the two jets. The 3:1 AR elliptical and circular burners produced similar carbon monoxide and nitric oxide emission indexes over the range of equivalence ratios of 0.55 to 4.0, for laminar flames. (Abstract shortened by UMI.)

Greenhouse gases inventory and carbon balance of two dairy systems obtained from two methane-estimation methods.

PubMed

Cunha, C S; Lopes, N L; Veloso, C M; Jacovine, L A G; Tomich, T R; Pereira, L G R; Marcondes, M I

2016-11-15

The adoption of carbon inventories for dairy farms in tropical countries based on models developed from animals and diets of temperate climates is questionable. Thus, the objectives of this study were to estimate enteric methane (CH4) emissions through the SF6 tracer gas technique and through equations proposed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 and to calculate the inventory of greenhouse gas (GHG) emissions from two dairy systems. In addition, the carbon balance of these properties was estimated using enteric CH4 emissions obtained using both methodologies. In trial 1, the CH4 emissions were estimated from seven Holstein dairy cattle categories based on the SF6 tracer gas technique and on IPCC equations. The categories used in the study were prepubertal heifers (n=6); pubertal heifers (n=4); pregnant heifers (n=5); high-producing (n=6); medium-producing (n=5); low-producing (n=4) and dry cows (n=5). Enteric methane emission was higher for the category comprising prepubertal heifers when estimated by the equations proposed by the IPCC Tier 2. However, higher CH4 emissions were estimated by the SF6 technique in the categories including medium- and high-producing cows and dry cows. Pubertal heifers, pregnant heifers, and low-producing cows had equal CH4 emissions as estimated by both methods. In trial 2, two dairy farms were monitored for one year to identify all activities that contributed in any way to GHG emissions. The total emission from Farm 1 was 3.21t CO2e/animal/yr, of which 1.63t corresponded to enteric CH4. Farm 2 emitted 3.18t CO2e/animal/yr, with 1.70t of enteric CH4. IPCC estimations can underestimate CH4 emissions from some categories while overestimate others. However, considering the whole property, these discrepancies are offset and we would submit that the equations suggested by the IPCC properly estimate the total CH4 emission and carbon balance of the properties. Thus, the IPCC equations should be utilized with caution, and the herd composition should be analysed at the property level. When the carbon stock in pasture and other crops was considered, the carbon balance suggested that both farms are sustainable for GHG, by both methods. On the other hand, carbon balance without carbon stock, by both methods, suggests that farms emit more carbon than the system is capable of stock. Copyright © 2016 Elsevier B.V. All rights reserved.

COSP: Satellite simulation software for model assessment

DOE PAGES

Bodas-Salcedo, A.; Webb, M. J.; Bony, S.; ...

2011-08-01

Errors in the simulation of clouds in general circulation models (GCMs) remain a long-standing issue in climate projections, as discussed in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. This highlights the need for developing new analysis techniques to improve our knowledge of the physical processes at the root of these errors. The Cloud Feedback Model Intercomparison Project (CFMIP) pursues this objective, and under that framework the CFMIP Observation Simulator Package (COSP) has been developed. COSP is a flexible software tool that enables the simulation of several satellite-borne active and passive sensor observations from model variables. The flexibilitymore » of COSP and a common interface for all sensors facilitates its use in any type of numerical model, from high-resolution cloud-resolving models to the coarser-resolution GCMs assessed by the IPCC, and the scales in between used in weather forecast and regional models. The diversity of model parameterization techniques makes the comparison between model and observations difficult, as some parameterized variables (e.g., cloud fraction) do not have the same meaning in all models. The approach followed in COSP permits models to be evaluated against observations and compared against each other in a more consistent manner. This thus permits a more detailed diagnosis of the physical processes that govern the behavior of clouds and precipitation in numerical models. The World Climate Research Programme (WCRP) Working Group on Coupled Modelling has recommended the use of COSP in a subset of climate experiments that will be assessed by the next IPCC report. Here we describe COSP, present some results from its application to numerical models, and discuss future work that will expand its capabilities.« less

Population pharmacokinetics and pharmacodynamics of ticagrelor and AR-C124910XX in Chinese healthy male subjects.

PubMed

Liu, Shuaibing; Xue, Ling; Shi, Xiangfen; Sun, Zhiyong; Zhu, Zhenfeng; Zhang, Xiaojian; Tian, Xin

2018-06-01

Ticagrelor, the first reversible P2Y 12 receptor antagonist, exhibits faster onset and offset of antiplatelet effects and more consistent platelet inhibition than clopidogrel in both healthy subjects and patients with stable coronary artery disease. The objectives of this study were to establish a population pharmacokinetics (PK) and pharmacodynamics (PD) model of ticagrelor and to provide a theoretical basis for the optimization of ticagrelor treatment in clinic. A single oral dose of 180 mg ticagrelor was administered to 14 healthy male subjects in a randomized study. Common single-nucleotide polymorphisms (SNPs) in biotransformation enzymes CYP3A4 and CYP3A5 (CYP3A4*1G and CYP3A5*3) were genotyped by PCR-direct sequencing. Blood samples were collected to measure plasma concentrations of ticagrelor and its active metabolite AR-C124910XX and maximal platelet inhibition. Various models were evaluated to characterize the pharmacokinetics of ticagrelor and AR-C124910XX as well as their PK-PD relationship. Covariates that may potentially affect PK or PD of ticagrelor and AR-C124910XX were included and assessed. Simulation for dosage regimen was performed based on the final PK-PD model. Ticagrelor and AR-C124910XX PK were best described by a two-compartment model with first-order transit absorption model. CYP3A4*1G increased clearance for AR-C124910XX, but had no significant effect on ticagrelor clearance. The relationship between concentration and platelet response of ticagrelor was best described by a turnover model. Simulation results indicated that a lower dosage regimen of 30 mg maintenance dose (MD) could produce an anticipated anti-platelet response in comparison to the routine clinical dosage regimen (180 mg loading dose (LD), 90 mg MD). Our study developed a population PK-PD model for ticagrelor and further simulation for dosage regimen was performed based on the final model. Compared to the current recommended dosage regimen (180 mg LD, 90 mg MD), our simulation result of a relatively lower dose (30 mg MD) could also obtain an acceptable anti-platelet response, which may provide a reference for further dosage regimen design in Chinese population.

Evaluation and characterization of anti-estrogenic and anti-androgenic activities in soil samples along the Second Songhua River, China.

PubMed

Li, Jian; Wang, Yafei; Kong, Dongdong; Wang, Jinsheng; Teng, Yanguo; Li, Na

2015-11-01

In the present study, re-combined estrogen receptor (ER) and androgen receptor (AR) gene yeast assays combined with a novel approach based on Monte Carlo simulation were used for evaluation and characterization of soil samples collected from Jilin along the Second Songhua River to assess their antagonist/agonist properties for ER and AR. The results showed that estrogenic activity only occurred in the soil samples collected in the agriculture area, but most soil samples showed anti-estrogenic activities, and the bioassay-derived 4-hydroxytamoxifen equivalents ranged from N.D. to 23.51 μg/g. Hydrophilic substance fractions were determined as potential contributors associated with anti-estrogenic activity in these soil samples. Moreover, none of the soil samples exhibited AR agonistic potency, whereas 54% of the soil samples exhibited AR antagonistic potency. The flutamide equivalents varied between N.D. and 178.05 μg/g. Based on Monte Carlo simulation-related mass balance analysis, the AR antagonistic activities were significantly correlated with the media polar and polar fractions. All of these results support that this novel calculation method can be adopted effectively to quantify and characterize the ER/AR agonists and antagonists of the soil samples, and these data could help provide useful information for future management and remediation efforts.

Molecular dynamics computer simulation of permeation in solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pohl, P.I.; Heffelfinger, G.S.; Fisler, D.K.

1997-12-31

In this work the authors simulate permeation of gases and cations in solid models using molecular mechanics and a dual control volume grand canonical molecular dynamics technique. The molecular sieving nature of microporous zeolites are discussed and compared with that for amorphous silica made by sol-gel methods. One mesoporous and one microporous membrane model are tested with Lennard-Jones gases corresponding to He, H{sub 2}, Ar and CH{sub 4}. The mesoporous membrane model clearly follows a Knudsen diffusion mechanism, while the microporous model having a hard-sphere cutoff pore diameter of {approximately}3.4 {angstrom} demonstrates molecular sieving of the methane ({sigma} = 3.8more » {angstrom}) but anomalous behavior for Ar ({sigma} = 3.4 {angstrom}). Preliminary results of Ca{sup +} diffusion in calcite and He/H{sub 2} diffusion in polyisobutylene are also presented.« less

Assessing the present and future probability of Hurricane Harvey's rainfall

NASA Astrophysics Data System (ADS)

Emanuel, Kerry

2017-11-01

We estimate, for current and future climates, the annual probability of areally averaged hurricane rain of Hurricane Harvey's magnitude by downscaling large numbers of tropical cyclones from three climate reanalyses and six climate models. For the state of Texas, we estimate that the annual probability of 500 mm of area-integrated rainfall was about 1% in the period 1981–2000 and will increase to 18% over the period 2081–2100 under Intergovernmental Panel on Climate Change (IPCC) AR5 representative concentration pathway 8.5. If the frequency of such event is increasingly linearly between these two periods, then in 2017 the annual probability would be 6%, a sixfold increase since the late 20th century.

Modelling regional climate change and urban planning scenarios and their impacts on the urban environment in two cities with WRF-ACASA

NASA Astrophysics Data System (ADS)

Falk, M.; Pyles, R. D.; Marras, S.; Spano, D.; Paw U, K. T.

2011-12-01

The number of urban metabolism studies has increased in recent years, due to the important impact that energy, water and carbon exchange over urban areas have on climate change. Urban modeling is therefore crucial in the future design and management of cities. This study presents the ACASA model coupled to the Weather Research and Forecasting (WRF-ARW) mesoscale model to simulate urban fluxes at a horizontal resolution of 200 meters for urban areas of roughly 100 km^2. As part of the European Project "BRIDGE", these regional simulations were used in combination with remotely sensed data to provide constraints on the land surface types and the exchange of carbon and energy fluxes from urban centers. Surface-atmosphere exchanges of mass and energy were simulated using the Advanced Canopy Atmosphere Soil Algorithm (ACASA). ACASA is a multi-layer high-order closure model, recently modified to work over natural, agricultural as well as urban environments. In particular, improvements were made to account for the anthropogenic contribution to heat and carbon production. For two cities four climate change and four urban planning scenarios were simulated: The climate change scenarios include a base scenario (Sc0: 2008 Commit in IPCC), a medium emission scenario (Sc1: IPCC A2), a worst case emission scenario (Sce2: IPCC A1F1) and finally a best case emission scenario (Sce3: IPCC B1). The urban planning scenarios include different development scenarios such as smart growth. The two cities are a high latitude city, Helsinki (Finland) and an historic city, Florence (Italy). Helsinki is characterized by recent, rapid urbanization that requires a substantial amount of energy for heating, while Florence is representative of cities in lower latitudes, with substantial cultural heritage and a comparatively constant architectural footprint over time. In general, simulated fluxes matched the point observations well and showed consistent improvement in the energy partitioning over urban regions. We present comparisons of observed (EC) tower flux observations from the Florence (Ximeniano) site for 1-9 April, 2008 with results from two sets of high-resolution simulations: the first using dynamically-downscaled input/boundary conditions (Model-0) and the second using fully nested WRF-ACASA (Model-1). In each simulation the model physics are the same; only the WRF domain configuration differs. Preliminary results (Figure 1) indicate a degree of parity (and a slight statistical improvement), in the performances of Model-1 vs. that of Model-0 with respect to observed. Figure 1 (below) shows air temperature values from observed and both model estimates. Additional results indicate that care must be taken to configure the WRF domain, as performance appears to be sensitive to model configuration.

Galbanic acid decreases androgen receptor abundance and signaling and induces G1 arrest in prostate cancer cells

PubMed Central

Zhang, Yong; Kim, Kwan-Hyun; Zhang, Wei; Guo, Yinglu; Kim, Sung-Hoon; Lü, Junxuan

2011-01-01

Androgen receptor (AR) signaling is crucial for the genesis and progression of prostate cancer (PCa). We compared the growth responses of AR(+) LNCaP and LNCaP C4-2 vs. AR(−) DU145 and PC-3 PCa cell lines to galbanic acid (GBA) isolated from the resin of medicinal herb Ferula assafoetida and assessed their connection to AR signaling and cell cycle regulatory pathways. Our results showed that GBA preferentially suppressed AR(+) PCa cell growth than AR(−) PCa cells. GBA induced a caspase-mediated apoptosis that was attenuated by a general caspase inhibitor. Subapoptotic GBA down-regulated AR protein in LNCaP cells primarily through promoting its proteasomal degradation, and inhibited AR-dependent transcription without affecting AR nuclear translocation. Whereas docking simulations predicted binding of GBA to the AR ligand binding domain with similarities and differences with the AR antagonist drug bicalutamide, LNCaP cell culture assays did not detect agonist activity of GBA. GBA and bicalutamide exerted greater than additive inhibitory effect on cell growth when used together. Subapoptotic GBA induced G1 arrest associated with an inhibition of cyclin/CDK4/6 pathway, especially cyclin D1 without the causal involvement of CDK inhibitory proteins P21Cip1 and P27Kip1. In summary, the novelty of GBA as an anti-AR compound resides in the distinction between GBA and bicalutamide with respect to AR protein turnover and a lack of agonist effect. Our observations of anti-AR and cell cycle arrest actions plus the anti-angiogenesis effect reported elsewhere suggest GBA as a multi-targeting drug candidate for the prevention and therapy of PCa. PMID:21328348

Integrated Farm System Model Version 4.3 and Dairy Gas Emissions Model Version 3.3 Software development and distribution

USDA-ARS?s Scientific Manuscript database

Modeling routines of the Integrated Farm System Model (IFSM version 4.2) and Dairy Gas Emission Model (DairyGEM version 3.2), two whole-farm simulation models developed and maintained by USDA-ARS, were revised with new components for: (1) simulation of ammonia (NH3) and greenhouse gas emissions gene...

Effect of air humidity on the removal of carbon tetrachloride from air using Cu-BTC metal-organic framework.

PubMed

Martín-Calvo, Ana; García-Pérez, Elena; García-Sánchez, Almudena; Bueno-Pérez, Rocío; Hamad, Said; Calero, Sofia

2011-06-21

We have used interatomic potential-based simulations to study the removal of carbon tetrachloride from air at 298 K, using Cu-BTC metal organic framework. We have developed new sets of Lennard-Jones parameters that accurately describe the vapour-liquid equilibrium curves of carbon tetrachloride and the main components from air (oxygen, nitrogen, and argon). Using these parameters we performed Monte Carlo simulations for the following systems: (a) single component adsorption of carbon tetrachloride, oxygen, nitrogen, and argon molecules, (b) binary Ar/CCl(4), O(2)/CCl(4), and N(2)/CCl(4) mixtures with bulk gas compositions 99 : 1 and 99.9 : 0.1, (c) ternary O(2)/N(2)/Ar mixtures with both, equimolar and 21 : 78 : 1 bulk gas composition, (d) quaternary mixture formed by 0.1% of CCl(4) pollutant, 20.979% O(2), 77.922% N(2), and 0.999% Ar, and (e) five-component mixtures corresponding to 0.1% of CCl(4) pollutant in air with relative humidity ranging from 0 to 100%. The carbon tetrachloride adsorption selectivity and the self-diffusivity and preferential sitting of the different molecules in the structure are studied for all the systems.

Generalized EC&LSS computer program configuration control

NASA Technical Reports Server (NTRS)

Blakely, R. L.

1976-01-01

The generalized environmental control and life support system (ECLSS) computer program (G189A) simulation of the shuttle orbiter ECLSS was upgraded. The G189A component model configuration was changed to represent the current PV102 and subsequent vehicle ECLSS configurations as defined by baseline ARS and ATCS schematics. The diagrammatic output schematics of the gas, water, and freon loops were also revised to agree with the new ECLSS configuration. The accuracy of the transient analysis was enhanced by incorporating the thermal mass effects of the equipment, structure, and fluid in the ARS gas and water loops and in the ATCS freon loops. The sources of the data used to upgrade the simulation are: (1) ATCS freon loop line sizes and lengths; (2) ARS water loop line sizes and lengths; (3) ARS water loop and ATCS freon loop component and equipment weights; and (4) ARS cabin and avionics bay thermal capacitance and conductance values. A single G189A combination master program library tape was generated which contains all of the master program library versions which were previously maintained on separate tapes. A new component subroutine, PIPETL, was developed and incorporated into the G189A master program library.

Statistical Processing Methods for Polarimetric Imagery

DTIC Science & Technology

2008-09-01

c ) G.G. Stokes portrait normalized bounds 5 10 15 20 0 0.2 0.4 0.6 0.8 1 N or m al iz ed v ar ia nc e Number of frames average...Bar target Stokes bounds 0 10 20 30 40 50 60 10 −2 10 0 10 2 10 4 10 6 N or m al iz ed v ar ia nc e Channel spacing S 0 S 1 S 2 ( c ) PC board...0.6 0.7 iteration N M S E multichannel single channel ( c ) S2 Figure 4.7: NMSE quartiles for the Simulated Stokes

Global Analysis of Climate Change Projection Effects on Atmospheric Rivers

NASA Astrophysics Data System (ADS)

Espinoza, Vicky; Waliser, Duane E.; Guan, Bin; Lavers, David A.; Ralph, F. Martin

2018-05-01

A uniform, global approach is used to quantify how atmospheric rivers (ARs) change between Coupled Model Intercomparison Project Phase 5 historical simulations and future projections under the Representative Concentration Pathway (RCP) 4.5 and RCP8.5 warming scenarios. The projections indicate that while there will be 10% fewer ARs in the future, the ARs will be 25% longer, 25% wider, and exhibit stronger integrated water vapor transports (IVTs) under RCP8.5. These changes result in pronounced increases in the frequency (IVT strength) of AR conditions under RCP8.5: 50% (25%) globally, 50% (20%) in the northern midlatitudes, and 60% (20%) in the southern midlatitudes. The models exhibit systematic low biases across the midlatitudes in replicating historical AR frequency ( 10%), zonal IVT ( 15%), and meridional IVT ( 25%), with sizable intermodel differences. A more detailed examination of six regions strongly impacted by ARs suggests that the western United States, northwestern Europe, and southwestern South America exhibit considerable intermodel differences in projected changes in ARs.

Climatic Droughts and the Impacts on Crop Yields in Northern India during the Past Century

NASA Astrophysics Data System (ADS)

Ge, Y.; Cai, X.; Zhu, T.

2014-12-01

Drought has become an increasingly severe threat to water and food security recently. This study presents a novel method to calculate the return period of drought, considering drought as event characterized by expected drought inter-arrival time, duration, severity and peak intensity. Recently, Copula distribution, a multivariable probability distribution, is used to deal with strongly correlated variables in analyzing complex hydrologic phenomenon. This study assesses drought conditions in Northern India, including 8 sites, in the past century using Palmer Drought Severity Index (PDSI) from two latest datasets, Dai (2011, 2013) and Sheffield et al. (2012), which concluded conflicting results about global average drought trend. Our results include the change of the severity, intensity and duration of drought events during the past century and the impact of the drought condition on crop yields in the region. It is found that drought variables are highly correlated, thus copulas joint distribution enables the estimation of multi-variate return period. Based on Dai's dataset from 1900 to 2012, for a fixed drought return period the severity and duration is lower for the period before1955 in sites close to the Indus basin (site 1) or off the coast of the Indian Ocean (Bay of Bengal) (site 8), while they are higher for the period after 1955 in other inland sites (sites 3-7), (e.g., severity in Fig.1). Projections based on two models (IPCC AR4 and AR5) in Dai (2011, 2013) suggested less severity and shorter duration in longer-year drought (e.g., 100-year drought), but larger in shorter-year drought (e.g., 2-year drought). Drought could bring nonlinear responses and unexpected losses in agriculture system, thus prediction and management are essential. Therefore, in the years with extreme drought conditions, impact assessment of drought on crop yield of corn, barley, wheat and sorghum will be also conducted through correlating crop yields with drought conditions during corresponding growing seasons. A. Dai, J. Geophys. Res., 116, D12115 (2011).A. Dai, Nature Climate Change, 3, 52-58 (2013). J. Sheffield, E.F. Wood, M. L. Roderick, Nature, 491, 435-438 (2012) Fig. 1 Return period for severity from 1900 to 1954 (green), from 1955 to 2012 (red), and from 2013 to 2099 (black for AR4, blue for AR5), respectively for 8 sites.

Failure analysis of parameter-induced simulation crashes in climate models

NASA Astrophysics Data System (ADS)

Lucas, D. D.; Klein, R.; Tannahill, J.; Ivanova, D.; Brandon, S.; Domyancic, D.; Zhang, Y.

2013-01-01

Simulations using IPCC-class climate models are subject to fail or crash for a variety of reasons. Quantitative analysis of the failures can yield useful insights to better understand and improve the models. During the course of uncertainty quantification (UQ) ensemble simulations to assess the effects of ocean model parameter uncertainties on climate simulations, we experienced a series of simulation crashes within the Parallel Ocean Program (POP2) component of the Community Climate System Model (CCSM4). About 8.5% of our CCSM4 simulations failed for numerical reasons at combinations of POP2 parameter values. We apply support vector machine (SVM) classification from machine learning to quantify and predict the probability of failure as a function of the values of 18 POP2 parameters. A committee of SVM classifiers readily predicts model failures in an independent validation ensemble, as assessed by the area under the receiver operating characteristic (ROC) curve metric (AUC > 0.96). The causes of the simulation failures are determined through a global sensitivity analysis. Combinations of 8 parameters related to ocean mixing and viscosity from three different POP2 parameterizations are the major sources of the failures. This information can be used to improve POP2 and CCSM4 by incorporating correlations across the relevant parameters. Our method can also be used to quantify, predict, and understand simulation crashes in other complex geoscientific models.

Failure analysis of parameter-induced simulation crashes in climate models

NASA Astrophysics Data System (ADS)

Lucas, D. D.; Klein, R.; Tannahill, J.; Ivanova, D.; Brandon, S.; Domyancic, D.; Zhang, Y.

2013-08-01

Simulations using IPCC (Intergovernmental Panel on Climate Change)-class climate models are subject to fail or crash for a variety of reasons. Quantitative analysis of the failures can yield useful insights to better understand and improve the models. During the course of uncertainty quantification (UQ) ensemble simulations to assess the effects of ocean model parameter uncertainties on climate simulations, we experienced a series of simulation crashes within the Parallel Ocean Program (POP2) component of the Community Climate System Model (CCSM4). About 8.5% of our CCSM4 simulations failed for numerical reasons at combinations of POP2 parameter values. We applied support vector machine (SVM) classification from machine learning to quantify and predict the probability of failure as a function of the values of 18 POP2 parameters. A committee of SVM classifiers readily predicted model failures in an independent validation ensemble, as assessed by the area under the receiver operating characteristic (ROC) curve metric (AUC > 0.96). The causes of the simulation failures were determined through a global sensitivity analysis. Combinations of 8 parameters related to ocean mixing and viscosity from three different POP2 parameterizations were the major sources of the failures. This information can be used to improve POP2 and CCSM4 by incorporating correlations across the relevant parameters. Our method can also be used to quantify, predict, and understand simulation crashes in other complex geoscientific models.

UV-VIS backscattering measurements on atmospheric particles mixture using polarization lidar coupled with numerical simulations and laboratory experiments

NASA Astrophysics Data System (ADS)

Miffre, Alain; Francis, Mirvatte; Anselmo, Christophe; Rairoux, Patrick

2015-04-01

As underlined by the latest IPCC report [1], tropospheric aerosols are nowadays recognized as one of the main uncertainties affecting the Earth's climate and human health. This issue is not straightforward due to the complexity of these nanoparticles, which present a wide range of sizes, shapes and chemical composition, which vary as a function of altitude, especially in the troposphere, where strong temperature variations are encountered under different water vapour content (from 10 to 100 % relative humidity). During this oral presentation, I will first present the scientific context of this research. Then, the UV-VIS polarimeter instrument and the subsequent calibration procedure [2] will be presented, allowing quantitative evaluation of particles backscattering coefficients in the atmosphere. In this way, up to three-component particles external mixtures can be partitioned into their spherical and non-spherical components, by coupling UV-VIS depolarization lidar measurements with numerical simulations of backscattering properties specific to non-spherical particles, such as desert dust or sea-salt particles [3], by applying the T-matrix numerical code [4]. This combined methodology is new, as opposed to the traditional approach using the lidar and T-matrix methodologies separately. In complement, recent laboratory findings [5] and field applications [6] will be presented, enhancing the sensitivity of the UV-VIS polarimeter. References [1] IPCC report, Intergovernmental Panel on Climate Change, IPCC, (2013). [2] G. David, A. Miffre, B. Thomas, and P. Rairoux: "Sensitive and accurate dual-wavelength UV-VIS polarization detector for optical remote sensing of tropospheric aerosols," Appl. Phys. B 108, 197-216 (2012). [3] G. David, B. Thomas, T. Nousiainen, A. Miffre and P. Rairoux: "Retrieving simulated volcanic, desert dust, and sea-salt particle properties from two / three-component particle mixtures using UV-VIS polarization Lidar and T-matrix," Atmos. Chem Phys. 13, 6757-6776 (2013). [4] M.I. Mishchenko, L.D. Travis and A.A. Lacis: "Scattering, absorption and emission of Light by small particles," 3rd edition, Cambridge University Press UK, (2002). [5] G. David, B. Thomas, E. Coillet, A. Miffre, and P. Rairoux, Polarization-resolved exact light backscattering by an ensemble of particles in air, Opt. Exp., 21, No. 16, 18624-18639, (2013). [6] G. David, B. Thomas, Y. Dupart, B. D'Anna, C. George, A. Miffre and P. Rairoux, UV polarization lidar for remote sensing new particles formation in the atmosphere, Opt. Exp., 22, A1009-A1022, (2014).

Simulation of an ensemble of future climate time series with an hourly weather generator

NASA Astrophysics Data System (ADS)

Caporali, E.; Fatichi, S.; Ivanov, V. Y.; Kim, J.

2010-12-01

There is evidence that climate change is occurring in many regions of the world. The necessity of climate change predictions at the local scale and fine temporal resolution is thus warranted for hydrological, ecological, geomorphological, and agricultural applications that can provide thematic insights into the corresponding impacts. Numerous downscaling techniques have been proposed to bridge the gap between the spatial scales adopted in General Circulation Models (GCM) and regional analyses. Nevertheless, the time and spatial resolutions obtained as well as the type of meteorological variables may not be sufficient for detailed studies of climate change effects at the local scales. In this context, this study presents a stochastic downscaling technique that makes use of an hourly weather generator to simulate time series of predicted future climate. Using a Bayesian approach, the downscaling procedure derives distributions of factors of change for several climate statistics from a multi-model ensemble of GCMs. Factors of change are sampled from their distributions using a Monte Carlo technique to entirely account for the probabilistic information obtained with the Bayesian multi-model ensemble. Factors of change are subsequently applied to the statistics derived from observations to re-evaluate the parameters of the weather generator. The weather generator can reproduce a wide set of climate variables and statistics over a range of temporal scales, from extremes, to the low-frequency inter-annual variability. The final result of such a procedure is the generation of an ensemble of hourly time series of meteorological variables that can be considered as representative of future climate, as inferred from GCMs. The generated ensemble of scenarios also accounts for the uncertainty derived from multiple GCMs used in downscaling. Applications of the procedure in reproducing present and future climates are presented for different locations world-wide: Tucson (AZ), Detroit (MI), and Firenze (Italy). The stochastic downscaling is carried out with eight GCMs from the CMIP3 multi-model dataset (IPCC 4AR, A1B scenario).

a Brazilian Vulnerability Index to Natural Disasters of Drought - in the Context of Climate Change

NASA Astrophysics Data System (ADS)

Camarinha, P. I., Sr.; Debortoli, N. S.; Hirota, M.

2015-12-01

Droughts are characterized as one of the main types of natural disasters that occur in Brazil. During the 1991-2012, droughts affected more than 14 million Brazilians, so that the concern for the following decades is about the potential impacts triggered by climate change. To analyze the vulnerability of the Brazilian municipalities to drought disasters, we have assessed the effects of climate change to droughts until the end of 21th century. A composite index was created based on three different dimensions: i) Exposure, represented by climate anomalies related to the drought process, such as changes in accumulated rainfall averages, interannual variability of rainfall, and the frequency and magnitude of severe droughts (measured by the Standardized Precipitation-Evapotranspiration Index); ii) Sensitivity, encompassing socioeconomic, demographic, land use and water management data; iii) Adaptive Capacity, consisting of socioeconomic and institutional data from Brazilian municipalities, such as the Human Development Index (HDI), social inequality (Gini index) and illiteracy rate. The climate variables used in this study are results from simulations of the Regional Climate Model Eta (with a downscaling of 20km spatial resolution) nested with two global climate models (HadGEM ES and MIROC 5) and was provided by National Institute for Space Research. The baseline period was 1961-1990 and future periods was 2011-2040; 2041-2070 and 2071-2099. For the simulations of future climate it was used the 4.5 and 8.5 IPCC/AR5 RCP (Representative Concentration Pathways) scenarios. All variables used in this study was handled, exploited and related in a Geographic Information System (GIS). The methodology allowed the identification of vulnerability hotspots, the targeting of adaptation strategies and the development of public policy to minimize the potential impacts of future droughts. The final results (see attached image) indicate that the most vulnerable regions are located in the Midwest, in the northeastern Brazilian semi-arid and also on western Amazon.

Dissemination of Climate Model Output to the Public and Commercial Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert Stockwell, PhD

2010-09-23

Climate is defined by the Glossary of Meteorology as the mean of atmospheric variables over a period of time ranging from as short as a few months to multiple years and longer. Although the term climate is often used to refer to long-term weather statistics, the broader definition of climate is the time evolution of a system consisting of the atmosphere, hydrosphere, lithosphere, and biosphere. Physical, chemical, and biological processes are involved in interactions among the components of the climate system. Vegetation, soil moisture, and glaciers are part of the climate system in addition to the usually considered temperature andmore » precipitation (Pielke, 2008). Climate change refers to any systematic change in the long-term statistics of climate elements (such as temperature, pressure, or winds) sustained over several decades or longer. Climate change can be initiated by external forces, such as cyclical variations in the Earth's solar orbit that are thought to have caused glacial and interglacial periods within the last 2 million years (Milankovitch, 1941). However, a linear response to astronomical forcing does not explain many other observed glacial and interglacial cycles (Petit et al., 1999). It is now understood that climate is influenced by the interaction of solar radiation with atmospheric greenhouse gasses (e.g., carbon dioxide, chlorofluorocarbons, methane, nitrous oxide, etc.), aerosols (airborne particles), and Earth's surface. A significant aspect of climate are the interannual cycles, such as the El Nino La Nina cycle which profoundly affects the weather in North America but is outside the scope of weather forecasts. Some of the most significant advances in understanding climate change have evolved from the recognition of the influence of ocean circulations upon the atmosphere (IPCC, 2007). Human activity can affect the climate system through increasing concentrations of atmospheric greenhouse gases, air pollution, increasing concentrations of aerosol, and land alteration. A particular concern is that atmospheric levels of CO{sub 2} may be rising faster than at any time in Earth's history, except possibly following rare events like impacts from large extraterrestrial objects (AMS, 2007). Atmospheric CO{sub 2} concentrations have increased since the mid-1700s through fossil fuel burning and changes in land use, with more than 80% of this increase occurring since 1900. The increased levels of CO{sub 2} will remain in the atmosphere for hundreds to thousands of years. The complexity of the climate system makes it difficult to predict specific aspects of human-induced climate change, such as exactly how and where changes will occur, and their magnitude. The Intergovernmental Panel for Climate Change (IPCC) was established by World Meteorological Organization (WMO) and the United Nations in 1988. The IPCC was tasked with assessing the scientific, technical and socioeconomic information needed to understand the risk of human-induced climate change, its observed and projected impacts, and options for adaptation and mitigation. The IPCC concluded in its Fourth Assessment Report (AR4) that warming of the climate system is unequivocal, and that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increased in anthropogenic greenhouse gas concentrations (IPCC, 2007).« less

Kinetic and Potential Sputtering of Lunar Regolith: Contribution of Solar-Wind Heavy Ions

NASA Technical Reports Server (NTRS)

Meyer, F. W.; Harris, P. R.; Meyer, H. M., III; Hijiazi, H.; Barghouty, A. F.

2013-01-01

Sputtering of lunar regolith by protons as well as solar-wind heavy ions is considered. From preliminary measurements of H+, Ar+1, Ar+6 and Ar+9 ion sputtering of JSC-1A AGGL lunar regolith simulant at solar wind velocities, and TRIM simulations of kinetic sputtering yields, the relative contributions of kinetic and potential sputtering contributions are estimated. An 80-fold enhancement of oxygen sputtering by Ar+ over same-velocity H+, and an additional x2 increase for Ar+9 over same-velocity Ar+ was measured. This enhancement persisted to the maximum fluences investigated is approximately 1016/cm (exp2). Modeling studies including the enhanced oxygen ejection by potential sputtering due to the minority heavy ion multicharged ion solar wind component, and the kinetic sputtering contribution of all solar wind constituents, as determined from TRIM sputtering simulations, indicate an overall 35% reduction of near-surface oxygen abundance. XPS analyses of simulant samples exposed to singly and multicharged Ar ions show the characteristic signature of reduced (metallic) Fe, consistent with the preferential ejection of oxygen atoms that can occur in potential sputtering of some metal oxides.

Kinetic and Thermodynamic Characterization of Dihydrotestosterone-Induced Conformational Perturbations in Androgen Receptor Ligand-Binding Domain

PubMed Central

Jasuja, Ravi; Ulloor, Jagadish; Yengo, Christopher M.; Choong, Karen; Istomin, Andrei Y.; Livesay, Dennis R.; Jacobs, Donald J.; Swerdloff, Ronald S.; Mikšovská, Jaroslava; Larsen, Randy W.; Bhasin, Shalender

2009-01-01

Ligand-induced conformational perturbations in androgen receptor (AR) are important in coactivator recruitment and transactivation. However, molecular rearrangements in AR ligand-binding domain (AR-LBD) associated with agonist binding and their kinetic and thermodynamic parameters are poorly understood. We used steady-state second-derivative absorption and emission spectroscopy, pressure and temperature perturbations, and 4,4′-bis-anilinonaphthalene 8-sulfonate (bis-ANS) partitioning to determine the kinetics and thermodynamics of the conformational changes in AR-LBD after dihydrotestosterone (DHT) binding. In presence of DHT, the second-derivative absorption spectrum showed a red shift and a change in peak-to-peak distance. Emission intensity increased upon DHT binding, and center of spectral mass was blue shifted, denoting conformational changes resulting in more hydrophobic environment for tyrosines and tryptophans within a more compact DHT-bound receptor. In pressure perturbation calorimetry, DHT-induced energetic stabilization increased the Gibbs free energy of unfolding to 8.4 ± 1.3 kcal/mol from 3.5 ± 1.6 kcal/mol. Bis-ANS partitioning studies revealed that upon DHT binding, AR-LBD underwent biphasic rearrangement with a high activation energy (13.4 kcal/mol). An initial, molten globule-like burst phase (k ∼30 sec−1) with greater solvent accessibility was followed by rearrangement (k ∼0.01 sec−1), leading to a more compact conformation than apo-AR-LBD. Molecular simulations demonstrated unique sensitivity of tyrosine and tryptophan residues during pressure unfolding with rearrangement of residues in the coactivator recruitment surfaces distant from the ligand-binding pocket. In conclusion, DHT binding leads to energetic stabilization of AR-LBD domain and substantial rearrangement of residues distant from the ligand-binding pocket. DHT binding to AR-LBD involves biphasic receptor rearrangement including population of a molten globule-like intermediate state. PMID:19443608

Managing the Risks of Extreme Events and Disasters in a Changing Climate: Lessons for Adaptation to Climate Change (Invited)

NASA Astrophysics Data System (ADS)

Mastrandrea, M.; Field, C. B.; Mach, K. J.; Barros, V.

2013-12-01

The IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation, published in 2012, integrates expertise in climate science, disaster risk reduction, and adaptation to inform discussions on how to reduce and manage the risks of extreme events and disasters in a changing climate. Impacts and the risks of disasters are determined by the interaction of the physical characteristics of weather and climate events with the vulnerability of exposed human society and ecosystems. The Special Report evaluates the factors that make people and infrastructure vulnerable to extreme events, trends in disaster losses, recent and future changes in the relationship between climate change and extremes, and experience with a wide range of options used by institutions, organizations, and communities to reduce exposure and vulnerability, and improve resilience, to climate extremes. Actions ranging from incremental improvements in governance and technology to more transformational changes are assessed. The Special Report provides a knowledge base that is also relevant to the broader context of managing the risks of climate change through mitigation, adaptation, and other responses, assessed in the IPCC's Fifth Assessment Report (AR5), to be completed in 2014. These themes include managing risks through an iterative process involving learning about risks and the effectiveness of responses, employing a portfolio of actions tailored to local circumstances but with links from local to global scales, and considering additional benefits of actions such as improving livelihoods and well-being. The Working Group II contribution to the AR5 also examines the ways that extreme events and their impacts contribute to understanding of vulnerabilities and adaptation deficits in the context of climate change, the extent to which impacts of climate change are experienced through changes in the frequency and severity of extremes as opposed to mean changes, and the emergence of risks that are place-based vs. systemic.

Maynard Participation in Alaska Forum on the Environment Panel Discussion on Increasing Input to the US National Climate Assessment (NCA) and the Intergovernmental Panel on Climate Change (IPCC) Processes from Alaska, with Emphasis on Indigenous Peoples Issues

NASA Technical Reports Server (NTRS)

Maynard, Nancy G.

2012-01-01

Dr. Nancy Maynard was invited by the Alaska Forum on the Environment to participate in a Panel Discussion to discuss (1) background about what the US NCA and International IPCC assessments are, (2) the impact the assessments have on policy-making, (3) the process for participation in both assessments, (4) how we can increase participation by Indigenous Peoples such as Native Americans and Alaska Natives, (5) How we can increase historical and current impacts input from Native communities through stories, oral history, "grey" literature, etc. The session will be chaired by Dr. Bull Bennett, a cochair of the US NCA's chapter on "Native and Tribal Lands and Resources" and Dr. Maynard is the other co-chair of that chapter and they will discuss the latest activities under the NCA process relevant to Native Americans and Alaska Natives. Dr. Maynard is also a Lead Author of the "Polar Regions" chapter of the IPCC WG2 (5th Assessment) and she will describes some of the latest approaches by the IPCC to entrain more Indigenous peoples into the IPCC process.

Evaluation of modelled methane emissions over northern peatland sites

NASA Astrophysics Data System (ADS)

Gao, Yao; Burke, Eleanor; Chadburn, Sarah; Raivonen, Maarit; Susiluoto, Jouni; Vesala, Timo; Aurela, Mika; Lohila, Annalea; Aalto, Tuula

2017-04-01

Methane (CH4) is a powerful greenhouse gas, with approximately 34 times the global warming potential of carbon dioxide (CO2) over a century time horizon (IPCC, 2013). The strong sensitivity of methane emissions to environmental factors has led to concerns about potential positive feedbacks to climate change. Evaluation of the ability of the process-based land surface models of earth system models (ESMs) in simulating CH4 emission over peatland is needed for more precise future predictions. In this study, two peatland sites of poor and rich soil nutrient conditions, in southern and northern Finland respectively, are adopted. The measured CH4 fluxes at the two sites are used to evaluate the CH4 emissions simulated by the land surface model (JULES) of the UK Earth System model and by the Helsinki peatland methane emission model (HIMMELI), which is developed at Finnish Meteorological Institute and Helsinki University. In JULES, CH4 flux is simply related to soil temperature, wetland fraction and effective substrate availability. However, HIMMELI has detailed descriptions of microbial and transport processes for simulating CH4 flux. The seasonal dynamics of CH4 fluxes at the two sites are relatively well captured by both models, but model biases exist. Simulated CH4 flux is sensitive to water table depth (WTD) at both models. However, the simulated WTD is limited to be below ground in JULES. It is also important to have the annual cycle of LAI correct when coupling JULES with HIMMELI.

A CMIP5 Ensemble Assessment of Climate Change Impact on Durum Wheat Production in North Dakota, USA

NASA Astrophysics Data System (ADS)

Dillon, T. D.; Kirilenko, A.

2016-12-01

North Dakota is the main US and one of the world's leading producers of durum wheat (Triticum durum), the hardest wheat variety with high protein content, used in multiple food products. We investigated potential change in durum wheat production in connection with climate change. The study accounted for variations in environmental conditions by running a dynamic wheat yield model in thirteen climatically different regions of the state. North Dakota climate is representative of highly productive agricultural lands of the Northern Great Plains, which encompass five US states and two Canadian provinces. Eastern part of North Dakota has humid continental climate while the western past is semi-desert with distinct west-to east precipitation gradient. Low mean average temperatures (cir. +4C), and high temperature variability lead to relatively short growing season (cir. 130 days). Combined with limited rainfall (cir. 350 mm in the East and 560 mm in the West), it makes agriculture highly dependent on temperature and precipitation. Accordingly, climate change has high potential impact on crop production in the region. We used the ALMANAC crop growth model to simulate the production of durum wheat. Model performance was estimated by comparison of simulated yields with historical observations; and was found satisfactory (RMSE < 1.00 T/ha*yr). To account for uncertainty in projected future climate, we used an ensemble of 17 CMIP5 GCMs run under four IPCC AR5 RCP scenarios, for two time periods characteristic of the 2040s and the 2070s. GCM output data were further downscaled using MarkSim weather generator. We found statistically significant reductions in mean yields in 96% of model runs for both time periods (t-test for independent samples; p<.05). In 2040s climate, yield decrease varied from 17% for RCP 2.6 to 45% for RCP 8.5; in 2070s climate - from 35% for RCP2.6 to 73% for RCP 8.5. Further research will concentrate on crop fail risk analysis and geographical heterogeneity of simulated changes.

Great Plains Drought in Simulations of Twentieth Century

NASA Astrophysics Data System (ADS)

McCrary, R. R.; Randall, D. A.

2008-12-01

The Great Plains region of the United States was influenced by a number of multi-year droughts during the twentieth century. Most notable were the "Dust Bowl" drought of the 1930s and the 1950s Great Plains drought. In this study we evaluate the ability of three of the Coupled Global Climate Models (CGCMs) used in the Fourth Assessment Report (AR4) of the IPCC to simulate Great Plains drought with the same frequency and intensity as was observed during the twentieth century. The models chosen for this study are: GFDL CM 2.0, NCAR CCSM3, and UKMO HadCM3. We find that the models accurately capture the climatology of the hydrologic cycle of the Great Plains, but that they tend to overestimate the variability in Great Plains precipitation. We also find that in each model simulation at least one long-term drought occurs over the Great Plains region during their representations 20th Century Climate. The multi-year droughts produced by the models exhibit similar magnitudes and spatial scales as was observed during the twentieth century. This study also investigates the relative roles that external forcing from the tropical Pacific and local feedbacks between the land surface and the atmosphere have in the initiation and perpetuation of Great Plains drought in each model. We find that cool, La Nina-like conditions in the tropical pacific are often associated with long-term drought conditions over the Great Plains in GFDL CM 2.0 and UKMO HadCM3, but there appears to be no systematic relationship between tropical Pacific SST variability and Great Plains drought in CCSM3. It is possible the strong coupling between the land surface and the atmosphere in the NCAR model causes precipitation anomalies to lock into phase over the Great Plains thereby perpetuating drought conditions. Results from this study are intended to help assess whether or not these climate models are credible for use in the assessment of future drought over the Great Plains region of the United States.

Hybrid simulation of electron energy distributions and plasma characteristics in pulsed RF CCP sustained in Ar and SiH4/Ar discharges

NASA Astrophysics Data System (ADS)

Wang, Xi-Feng; Jia, Wen-Zhu; Song, Yuan-Hong; Zhang, Ying-Ying; Dai, Zhong-Ling; Wang, You-Nian

2017-11-01

Pulsed-discharge plasmas offer great advantages in deposition of silicon-based films due to the fact that they can suppress cluster agglomeration, moderate the energy of bombarding ions, and prolong the species' diffusion time on the substrate. In this work, a one-dimensional fluid/Monte-Carlo hybrid model is applied to study pulse modulated radio-frequency (RF) plasmas sustained in capacitively coupled Ar and SiH4/Ar discharges. First, the electron energy distributions in pulsed Ar and SiH4/Ar plasmas have been investigated and compared under identical discharge-circuit conditions. The electron energy distribution function (EEDF) in Ar discharge exhibits a familiar bi-Maxwellian shape during the power-on phase of the pulse, while a more complex (resembling a multi-Maxwellian) distribution with extra inflection points at lower energies is observed in the case of the SiH4/Ar mixture. These features become more prominent with the increasing fraction of SiH4 in the gas mixture. The difference in the shape of the EEDF (which is pronounced inside the plasma but not in the RF sheath where electron heating occurs) is mainly attributed to the electron-impact excitations of SiH4. During the power-off phase of the pulse, the EEDFs in both Ar and SiH4/Ar discharges evolve into bi-Maxwellian shapes, with shrinking high energy tails. Furthermore, the parameter of ion species in the case of SiH4/Ar discharge is strongly modulated by pulsing. For positive ions, such as SiH3+ and Si2H4+ , the particle fluxes overshoot at the beginning of the power-on interval. Meanwhile, for negative ions such as SiH2- and SiH3- , density profiles observed between the electrodes are saddle-shaped due to the repulsion by the self-bias electric field as it builds up. During the power-off phase, the wall fluxes of SiH2- and SiH3- gradually increase, leading to a significant decrease in the net surface charge density on the driven electrode. Compared with ions, the density of SiH3 is poorly modulated by pulsed power and is nearly constant over the entire modulation period, but the density of SiH2 shows a detectable decline in the afterglow. However, because of a much smaller content of SiH2, the deposition rate hardly shows any variation under the selected waveform of the pulse.

Spatial and Temporal Distributions of Carbonate Saturation State on the Mississippi River Dominated Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Huang, W. J.; Cai, W. J.; Wang, Y.; Hu, X.

2016-02-01

Carbonate saturation state (ΩAr) serves as an index of ocean acidification; however, its variation on river-dominated continental shelves remains unclear. Samples of total alkalinity (TA), dissolved inorganic carbon (DIC), and nutrients were taken from nine cruises on the Mississippi and Atchafalaya River dominated continental shelf during 2006 to 2010. The distributions of TA and DIC on sea surface generally follow salinity distributions, i.e. low on the inner shelf and high on the outer shelf. The riverine calcium concentration was considered to calculate ΩAr and the result showed high ΩAr (4 to 6) along the axis of the river plume trajectory, moderate ( 4) on the surface open gulf, and low (< 3) in the deep gulf. Strong seasonal variation of ΩAr was observed in the river endmembers, high in spring and low in winter. The ΩAr variation was dominated by mixing when salinities < 18. In waters of higher salinities, deficits of DIC from the conservative mixing lines were positively correlated to deficits of NO3 and the slope of regression line was close to the Redfield ratio after removing data affected by unbalanced Si and N. The fact that ΩAr was highly correlated to ΔDIC suggests that ΩAr was dominated by biological activity. Finally, model simulations suggest that the effect of increasing riverine TA (increasing ΩAr in low salinities zone) and the effect of decreasing riverine nitrate flux (decreasing ΩAr in middle-to-high salinities zone) on ΩAr might compensate each other in this study area.

A DSMC Study of Low Pressure Argon Discharge

NASA Astrophysics Data System (ADS)

Hash, David; Meyyappan, M.

1997-10-01

Work toward a self-consistent plasma simulation using the DSMC method for examination of the flowfields of low-pressure high density plasma reactors is presented. Presently, DSMC simulations for these applications involve either treating the electrons as a fluid or imposing experimentally determined values for the electron number density profile. In either approach, the electrons themselves are not physically simulated. Self-consistent plasma DSMC simulations have been conducted for aerospace applications but at a severe computational cost due in part to the scalar architectures on which the codes were employed. The present work attempts to conduct such simulations at a more reasonable cost using a plasma version of the object-oriented parallel Cornell DSMC code, MONACO, on an IBM SP-2. Due the availability of experimental data, the GEC reference cell is chosen to conduct preliminary investigations. An argon discharge is examined thus affording a simple chemistry set with eight gas-phase reactions and five species: Ar, Ar^+, Ar^*, Ar_2, and e where Ar^* is a metastable.

Engine component improvement: Performance improvement, JT9D-7 3.8 AR fan

NASA Technical Reports Server (NTRS)

Gaffin, W. O.

1980-01-01

A redesigned, fuel efficient fan for the JT9D-7 engine was tested. Tests were conducted to determine the effect of the 3.8 AR fan on performance, stability, operational characteristics, and noise of the JT9D-7 engine relative to the current 4.6 AR Bill-of-Material fan. The 3.8 AR fan provides increased fan efficiency due to a more advanced blade airfoil with increased chord, eliminating one part span shroud and reducing the number of fan blades and fan exit guide vanes. Engine testing at simulated cruise conditions demonstrated the predicted 1.3 percent improvement in specific fuel consumption with the redesigned 3.8 AR fan. Flight testing and sea level stand engine testing demonstrated exhaust gas temperature margins, fan and low pressure compressor stability, operational suitability, and noise levels comparable to the Bill-of-Material fan.

Atmospheric river influence on the intensification of extreme hydrologic events over the Western United States under climate change scenarios

NASA Astrophysics Data System (ADS)

Pagán, Brianna; Ashfaq, Moetasim; Nayak, Munir; Rastogi, Deeksha; Margulis, Steven; Pal, Jeremy

2017-04-01

The Western United States shares limited snowmelt driven water supplies amongst millions of people, a multi-billion dollar agriculture industry and fragile ecosystems. The climatology of the region is highly variable, characterized by the frequent occurrences of both flood and drought conditions that cause increasingly challenging water management issues. Although variable year to year, up to half of California's total precipitation can be linked to atmospheric rivers (ARs). Most notably, ARs have been connected to nearly every major historic flood in the region, establishing its critical role to water supply. Numerous prior studies have considered potential climate change impacts over the Western United States and have generally concluded that warmer temperatures will reduce snowpack and shift runoff timing, causing reductions to water supply. Here we examine the role of ARs as one mechanism for explaining projected increases in flood and drought frequency and intensity under climate change scenarios, vital information for water resource managers. A hierarchical modeling framework to downscale 11 coupled global climate models from CMIP5 is used to form an ensemble of high-resolution dynamically downscaled regional climate model (via RegCM4) simulations at 18-km and hydrological (via VIC) simulations at a 4-km resolution for baseline (1965-2005) and future (2010-2050) periods under RCP 8.5. Each ensemble member's ability to capture observational AR climatology over the baseline period is evaluated. Baseline to future period changes to AR size, duration, seasonal timing, trajectory, magnitude and frequency are presented. These changes to the characterizations of ARs in the region are used to determine if any links exist to changes in snowpack volume, runoff timing, and the occurrence of daily and annual cumulative extreme precipitation and runoff events. Shifts in extreme AR frequency and magnitude are expected to increase flood risks, which without adequate multi-year reservoir storage solutions could further strain water supply resources.

Characteristics and Scenarios Projection of Climate Change on the Tibetan Plateau

PubMed Central

Hao, Zhenchun; Ju, Qin; Jiang, Weijuan; Zhu, Changjun

2013-01-01

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents twenty-two global climate models (GCMs). In this paper, we evaluate the ability of 22 GCMs to reproduce temperature and precipitation over the Tibetan Plateau by comparing with ground observations for 1961~1900. The results suggest that all the GCMs underestimate surface air temperature and most models overestimate precipitation in most regions on the Tibetan Plateau. Only a few models (each 5 models for precipitation and temperature) appear roughly consistent with the observations in annual temperature and precipitation variations. Comparatively, GFCM21 and CGMR are able to better reproduce the observed annual temperature and precipitation variability over the Tibetan Plateau. Although the scenarios predicted by the GCMs vary greatly, all the models predict consistently increasing trends in temperature and precipitation in most regions in the Tibetan Plateau in the next 90 years. The results suggest that the temperature and precipitation will both increase in all three periods under different scenarios, with scenario A1 increasing the most and scenario A1B increasing the least. PMID:23970827

Signal Trees: Communicating Attribution of Climate Change Impacts Through Causal Chain Illustrations

NASA Astrophysics Data System (ADS)

Cutting, H.

2016-12-01

Communicating the attribution of current climate change impacts is a key task for engagment with the general public, news media and policy makers, particularly as climate events unfold in real time. The IPCC WGII in AR5 validated the use of causal chain illustrations to depict attribution of individual climate change impacts. Climate Signals, an online digital platform for mapping and cataloging climate change impacts (launched in May of 2016), explores the use of such illustrations for communicating attribution. The Climate Signals project has developed semi-automated graphing software to produce custom attribution trees for numerous climate change events. This effort offers lessons for engagement of the general public and policy makers in the attribution of climate change impacts.

Assessing the present and future probability of Hurricane Harvey's rainfall.

PubMed

Emanuel, Kerry

2017-11-28

We estimate, for current and future climates, the annual probability of areally averaged hurricane rain of Hurricane Harvey's magnitude by downscaling large numbers of tropical cyclones from three climate reanalyses and six climate models. For the state of Texas, we estimate that the annual probability of 500 mm of area-integrated rainfall was about 1% in the period 1981-2000 and will increase to 18% over the period 2081-2100 under Intergovernmental Panel on Climate Change (IPCC) AR5 representative concentration pathway 8.5. If the frequency of such event is increasingly linearly between these two periods, then in 2017 the annual probability would be 6%, a sixfold increase since the late 20th century. Copyright © 2017 the Author(s). Published by PNAS.

Climate-change-driven accelerated sea-level rise detected in the altimeter era.

PubMed

Nerem, R S; Beckley, B D; Fasullo, J T; Hamlington, B D; Masters, D; Mitchum, G T

2018-02-27

Using a 25-y time series of precision satellite altimeter data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3, we estimate the climate-change-driven acceleration of global mean sea level over the last 25 y to be 0.084 ± 0.025 mm/y 2 Coupled with the average climate-change-driven rate of sea level rise over these same 25 y of 2.9 mm/y, simple extrapolation of the quadratic implies global mean sea level could rise 65 ± 12 cm by 2100 compared with 2005, roughly in agreement with the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) model projections. Copyright © 2018 the Author(s). Published by PNAS.

Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing

NASA Astrophysics Data System (ADS)

Etminan, M.; Myhre, G.; Highwood, E. J.; Shine, K. P.

2016-12-01

New calculations of the radiative forcing (RF) are presented for the three main well-mixed greenhouse gases, methane, nitrous oxide, and carbon dioxide. Methane's RF is particularly impacted because of the inclusion of the shortwave forcing; the 1750-2011 RF is about 25% higher (increasing from 0.48 W m-2 to 0.61 W m-2) compared to the value in the Intergovernmental Panel on Climate Change (IPCC) 2013 assessment; the 100 year global warming potential is 14% higher than the IPCC value. We present new simplified expressions to calculate RF. Unlike previous expressions used by IPCC, the new ones include the overlap between CO2 and N2O; for N2O forcing, the CO2 overlap can be as important as the CH4 overlap. The 1750-2011 CO2 RF is within 1% of IPCC's value but is about 10% higher when CO2 amounts reach 2000 ppm, a value projected to be possible under the extended RCP8.5 scenario.

Methodologies for simulating impacts of climate change on crop production

USDA-ARS?s Scientific Manuscript database

Ecophysiological models of crop growth have seen wide use in IPCC and related assessments. However, the diversity of modeling approaches constrains cross-study syntheses and increases potential for bias. We reviewed 139 peer-reviewed papers dealing with climate change and agriculture, considering si...

Structural Changes Due to Antagonist Binding in Ligand Binding Pocket of Androgen Receptor Elucidated Through Molecular Dynamics Simulations.

PubMed

Sakkiah, Sugunadevi; Kusko, Rebecca; Pan, Bohu; Guo, Wenjing; Ge, Weigong; Tong, Weida; Hong, Huixiao

2018-01-01

When a small molecule binds to the androgen receptor (AR), a conformational change can occur which impacts subsequent binding of co-regulator proteins and DNA. In order to accurately study this mechanism, the scientific community needs a crystal structure of the Wild type AR (WT-AR) ligand binding domain, bound with antagonist. To address this open need, we leveraged molecular docking and molecular dynamics (MD) simulations to construct a structure of the WT-AR ligand binding domain bound with antagonist bicalutamide. The structure of mutant AR (Mut-AR) bound with this same antagonist informed this study. After molecular docking analysis pinpointed the suitable binding orientation of a ligand in AR, the model was further optimized through 1 μs of MD simulations. Using this approach, three molecular systems were studied: (1) WT-AR bound with agonist R1881, (2) WT-AR bound with antagonist bicalutamide, and (3) Mut-AR bound with bicalutamide. Our structures were very similar to the experimentally determined structures of both WT-AR with R1881 and Mut-AR with bicalutamide, demonstrating the trustworthiness of this approach. In our model, when WT-AR is bound with bicalutamide, Val716/Lys720/Gln733, or Met734/Gln738/Glu897 move and thus disturb the positive and negative charge clumps of the AF2 site. This disruption of the AF2 site is key for understanding the impact of antagonist binding on subsequent co-regulator binding. In conclusion, the antagonist induced structural changes in WT-AR detailed in this study will enable further AR research and will facilitate AR targeting drug discovery.

Greenhouse gas emissions from municipal solid waste management in Indian mega-cities: a case study of Chennai landfill sites.

PubMed

Jha, Arvind K; Sharma, C; Singh, Nahar; Ramesh, R; Purvaja, R; Gupta, Prabhat K

2008-03-01

Municipal solid waste generation rate is over-riding the population growth rate in all mega-cities in India. Greenhouse gas emission inventory from landfills of Chennai has been generated by measuring the site specific emission factors in conjunction with relevant activity data as well as using the IPCC methodologies for CH4 inventory preparation. In Chennai, emission flux ranged from 1.0 to 23.5mg CH4m(-2)h(-1), 6 to 460microg N2Om(-2)h(-1) and 39 to 906mg CO2m(2)h(-1) at Kodungaiyur and 0.9 to 433mg CH4m(-2)h(-1), 2.7 to 1200microg N2Om(-2)h(-1) and 12.3 to 964.4mg CO2m(-2)h(-1) at Perungudi. CH4 emission estimates were found to be about 0.12Gg in Chennai from municipal solid waste management for the year 2000 which is lower than the value computed using IPCC, 1996 [IPCC, 1996. Report of the 12th session of the intergovernmental panel of climate change, Mexico City, 1996] methodologies.

An Experiment to Evaluate Transfer of Low-Cost Simulator-Based Upset-Recovery Training

DTIC Science & Technology

2009-03-01

nclusve, LOC was the leadng cause of hull losses and passenger fataltes n worldwde ar transport operatons, causng almost 25% of all crashes ...research at the Calspan In-Flght Upset Recovery Tranng Program n Roswell , N.M.4 A second set of artcles focuses on centrfuge-based flght s...resulted n ar transport upsets leadng to uncontrolled crashes . Gawron used Calspan’s Learjet to test five groups of arlne plots wth varyng

Comparative Effectiveness of Tacrolimus-Based Steroid Sparing versus Steroid Maintenance Regimens in Kidney Transplantation: Results from Discrete Event Simulation.

PubMed

Desai, Vibha C A; Ferrand, Yann; Cavanaugh, Teresa M; Kelton, Christina M L; Caro, J Jaime; Goebel, Jens; Heaton, Pamela C

2017-10-01

Corticosteroids used as immunosuppressants to prevent acute rejection (AR) and graft loss (GL) following kidney transplantation are associated with serious cardiovascular and other adverse events. Evidence from short-term randomized controlled trials suggests that many patients on a tacrolimus-based immunosuppressant regimen can withdraw from steroids without increased AR or GL risk. To measure the long-term tradeoff between GL and adverse events for a heterogeneous-risk population and determine the optimal timing of steroid withdrawal. A discrete event simulation was developed including, as events, AR, GL, myocardial infarction (MI), stroke, cytomegalovirus, and new onset diabetes mellitus (NODM), among others. Data from the United States Renal Data System were used to estimate event-specific parametric regressions, which accounted for steroid-sparing regimen (avoidance, early 7-d withdrawal, 6-mo withdrawal, 12-mo withdrawal, and maintenance) as well as patients' demographics, immunologic risks, and comorbidities. Regression-equation results were used to derive individual time-to-event Weibull distributions, used, in turn, to simulate the course of patients over 20 y. Patients on steroid avoidance or an early-withdrawal regimen were more likely to experience AR (45.9% to 55.0% v. 33.6%, P < 0.05) and GL (51.5% to 68.8% v. 37.8%, P < 0.05) compared to patients on steroid maintenance. Patients in 6-mo and 12-mo steroid withdrawal groups were less likely to experience MI (11.1% v. 13.3%, P < 0.05), NODM (30.7% to 34.4% v. 37.7%, P < 0.05), and cardiac death (29.9% to 30.5% v. 32.4%, P < 0.05), compared to steroid maintenance. Strategies of 6- and 12-mo steroid withdrawal post-kidney transplantation are expected to reduce the rates of adverse cardiovascular events and other outcomes with no worsening of AR or GL rates compared with steroid maintenance.

Get Real: Augmented Reality for the Classroom

ERIC Educational Resources Information Center

Mitchell, Rebecca; DeBay, Dennis

2012-01-01

Kids love augmented reality (AR) simulations because they are like real-life video games. AR simulations allow students to learn content while collaborating face to face and interacting with a multimedia-enhanced version of the world around them. Although the technology may seem advanced, AR software makes it easy to develop content-based…

A Software Prototype For Accessing Large Climate Simulation Data Through Digital Globe Interface

NASA Astrophysics Data System (ADS)

Chaudhuri, A.; Sorokine, A.

2010-12-01

The IPCC suite of global Earth system models produced terabytes of data for the CMIP3/AR4 archive and is expected to reach the petabyte scale by CMIP5/AR5. Dynamic downscaling of global models based on regional climate models can potentially lead to even larger data volumes. The model simulations for global or regional climate models like CCSM3 or WRF are typically run on supercomputers like the ORNL/DOE Jaguar and the results are stored on high performance storage systems. Access to these results from a user workstation is impeded by a number of factors such as enormous data size, limited bandwidth of standard office networks, data formats which are not fully supported by applications. So, a user-friendly interface for accessing and visualizing these results over standard Internet connection is required to facilitate collaborative work among geographically dispersed groups of scientists. To address this problem, we have developed a virtual globe based application which enables the scientists to query, visualize and analyze the results without the need of large data transfers to desktops and department-level servers. We have used open-source NASA WorldWind as a virtual globe platform and extended it with modules capable of visualizing model outputs stored in NetCDF format, while the data resides on the high-performance system. Based on the query placed by the scientist, our system initiates data processing routines on the high performance storage system to subset the data and reduce its size and then transfer it back to scientist's workstation through secure shell tunnel. The whole operation is kept totally transparent to the scientist and for the most part is controlled from a point-and-click GUI. The virtual globe also serves as a common platform for geospatial data, allowing smooth integration of the model simulation results with geographic data from other sources such as various web services or user-specific data in local files, if required. Also the system has the capability of building and updating a metadata catalog on the high performance storage that presents a simplified summary of the stored variables, hiding the low-level details such as physical location, size or format of the files from the user. Since data are often contributed to the system from multiple sources, the metadata catalog provides the user with a bird's eye view of the recent status of the database. As a next step, we plan on parallelizing the metadata updating and query-driven data selection routines to reduce the query response time. At current stage, the system can be immediately useful in making climate model simulation results available to a greater number of researchers who need simple and intuitive visualization of the simulation data or want to perform some analysis on it. The system's utility can reach beyond this particular application since it is generic enough to be ported to other high performance systems and to enable easy access to other types of geographic data.

What is going on in augmented reality simulation in laparoscopic surgery?

PubMed

Botden, Sanne M B I; Jakimowicz, Jack J

2009-08-01

To prevent unnecessary errors and adverse results of laparoscopic surgery, proper training is of paramount importance. A safe way to train surgeons for laparoscopic skills is simulation. For this purpose traditional box trainers are often used, however they lack objective assessment of performance. Virtual reality laparoscopic simulators assess performance, but lack realistic haptic feedback. Augmented reality (AR) combines a virtual reality (VR) setting with real physical materials, instruments, and feedback. This article presents the current developments in augmented reality laparoscopic simulation. Pubmed searches were performed to identify articles regarding surgical simulation and augmented reality. Identified companies manufacturing an AR laparoscopic simulator received the same questionnaire referring to the features of the simulator. Seven simulators that fitted the definition of augmented reality were identified during the literature search. Five of the approached manufacturers returned a completed questionnaire, of which one simulator appeared to be VR and was therefore not applicable for this review. Several augmented reality simulators have been developed over the past few years and they are improving rapidly. We recommend the development of AR laparoscopic simulators for component tasks of procedural training. AR simulators should be implemented in current laparoscopic training curricula, in particular for laparoscopic suturing training.

Future Evolution of Marine Heat Waves in the Mediterranean: Coupled Regional Climate Projections

NASA Astrophysics Data System (ADS)

Darmaraki, Sofia; Somot, Samuel; Sevault, Florence; Nabat, Pierre; Cavicchia, Leone; Djurdjevic, Vladimir; Cabos, William; Sein, Dmitry

2017-04-01

FUTURE EVOLUTION OF MARINE HEAT WAVES IN THE MEDITERRANEAN : COUPLED REGIONAL CLIMATE PROJECTIONS The Mediterranean area is identified as a « Hot Spot » region, vulnerable to future climate change with potentially strong impacts over the sea. By 2100, climate models predict increased warming over the sea surface, with possible implications on the Mediterranean thermohaline and surface circulation,associated also with severe impacts on the ecosystems (e.g. fish habitat loss, species extinction and migration, invasive species). However, a robust assesment of the future evolution of the extreme marine temperatures remains still an open issue of primary importance, under the anthropogenic pressure. In this context, we study here the probability and characteristics of marine heat wave (MHW) occurrence in the Mediterranean Sea in future climate projections. To this end, we use an ensemble of fully coupled regional climate system models (RCSM) from the Med- CORDEX initiative. This multi-model approach includes a high-resolution representation of the atmospheric, land and ocean component, with a free air-sea interface.Specifically, dedicated simulations for the 20th and the 21st century are carried out with respect to the different IPCC-AR5 socioeconomic scenarios (1950-2100, RCP8.5, RCP4.5, RCP2.6). Model evaluation for the historical period is performed using satellite and in situ data. Then, the variety of factors that can cause the MHW (e.g. direct radiative forcing, ocean advection, stratification change) are examined to disentangle the dominant driving force. Finally, the spatial variability and temporal evolution of MHW are analyzed on an annual basis, along with additional integrated indicators, useful for marine ecosystems.

Examining the last few decades of global hydroclimate for evidence of anthropogenic change amidst natural variability

NASA Astrophysics Data System (ADS)

Seager, R.; Naik, N.; Ting, M.; Kushnir, Y.; Kelley, C. P.

2011-12-01

Climate models robustly predict that the deep tropics and mid-latitude-to-subpolar regions will moisten, and the subtropical dry zones both dry and expand, as a consequence of global warming driven by rising greenhouse gases. The models also predict that this transition to a more extreme climatological mean global hydroclimate should already be underway. Given the importance of these predictions it is an imperative that the climate science community assess whether there is evidence within the observational record that they are correct. This task is made difficult by the tremendous natural variability of the hydrological cycle on seasonal to multidecadal timescales. Here we will use instrumental observations, reanalyses, sea surface temperature forced atmosphere models and coupled model simulations, and a variety of methodologies, to attempt to separate global radiatively-forced hydroclimate change from ongoing natural variability. The results will be applied to explain trends and recent events in key regions such as Mexico, the United States and the Mediterranean. It is concluded that the signal of anthropogenic change is small compared to the amplitude of natural variability but that it is a discernible contributor. Globally the evidence reveals that radiatively-forced hydroclimate change is occurring with an amplitude and spatial pattern largely consistent with the predictions by IPCC AR4 models of hydroclimate change to date. However it will also be shown that the radiatively-forced component does not in and of itself provide a useful prediction of near term hydroclimate change because for many regions the amplitude of natural decadal variability is as large or larger. Useful predictions need to account for how natural variability may evolve as well as forced change.

Hydrologic response of Pacific Northwest river to climate change

NASA Astrophysics Data System (ADS)

Su, F.; Cuo, L.; Wu, H.; Mantua, N.; Lettenmaier, D. P.

2009-12-01

The climate of the Pacific Northwest (PNW - which we define as the Columbia River basin and watersheds draining to the Oregon and Washington coasts) is expected to warm by approximately 0.3°C per decade in the next 100 years based on the IPCC the Fourth Assessment Report (AR4) results. PNW hydrology is particularly sensitive to a warming climate because of the dominant role of snowmelt in seasonal streamflow. Timing shifts in seasonality of flows, peak discharge, and base flows will impact water resource management, regional electrical energy production, and freshwater ecosystems. In this work we update previous studies of implications of climate change on PNW hydrology using a macroscale hydrology model driven by simulations of temperature and precipitation downscaled from runs of 20 General Circulation Models (GCMs) under two emissions scenarios (lower B1 and mid-high A1B) in the 21st century. The hydrology model is implemented at 1/16th degree spatial resolution over the entire PNW. A (statistical) bias-correction and spatial disaggregation downscaling approach is used for translating the transient monthly climate model output into continuous daily forcings for the hydrologic analysis. We evaluate projected changes in snow water equivalent, seasonal streamflow, and frequency of peak low flows over a set of case study watersheds in the region. We also compare these hydrologic projections with previous analysis based on delta downscaling method over the PNW. This research is part of a project investigating climate change impacts on the future of wild Pacific salmon, and is a pilot effort to investigate the hydrologic sensitivity of salmon bearing watersheds around the entire North Pacific Rim.

The Current Status and Future of GNSS-Meteorology in Europe

NASA Astrophysics Data System (ADS)

Jones, J.; Guerova, G.; Dousa, J.; Dick, G.; Haan, de, S.; Pottiaux, E.; Bock, O.; Pacione, R.

2017-12-01

GNSS is a well established atmospheric observing system which can accurately sense water vapour, the most abundant greenhouse gas, accounting for 60-70% of atmospheric warming. Water vapour observations are currently under-sampled in operational meteorology and obtaining and exploiting additional high-quality humidity observations is essential to improve severe weather forecasting and climate monitoring. Inconsistencies introduced into long-term time series from improved GNSS processing algorithms make climate trend analysis challenging. Ongoing re-processing efforts using state-of-the-art models are underway which will provide consistent time series' of tropospheric data, using 15+ years of GNSS observations and from over 600 stations worldwide. These datasets will enable validation of systematic biases from a range of instrumentation, improve the knowledge of climatic trends of atmospheric water vapour, and will potentially be of great benefit to global and regional NWP reanalyses and climate model simulations (e.g. IPCC AR5) COST Action ES1206 is a 4-year project, running from 2013 to 2017, which has coordinated new and improved capabilities from concurrent developments in GNSS, meteorological and climate communities. For the first time, the synergy of multi-GNSS constellations has been used to develop new, more advanced tropospheric products, exploiting the full potential of multi-GNSS on a wide range of temporal and spatial scales - from real-time products monitoring and forecasting severe weather, to the highest quality post-processed products suitable for climate research. The Action has also promoted the use of meteorological data as an input to real-time GNSS positioning, navigation, and timing services and has stimulated knowledge and data transfer throughout Europe and beyond. This presentation will give an overview of COST Action ES1206 plus an overview of ground-based GNSS-meteorology in Europe in general, including current status and future opportunities.

Crop response to climate: ecophysical models

USDA-ARS?s Scientific Manuscript database

Ecophysiological models were the dominant tools used to estimate the potential impact of climate change in agroecosystems in the Third and Fourth Assessment Reports of the IPCC and are widely used elsewhere in climate change research. These models, also known as “crop models” or “simulation models”,...

Impacts of episodic storms on coastal wetland processes in the Northeastern U.S.

EPA Science Inventory

Climate model simulations corresponding to IPCC emissions scenarios suggest that by 2100, increases in precipitation intensity, the number of heavy precipitation events, and the intensity of the wettest events are all expected to increase, while concurrently, one to three month d...

Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

NASA Astrophysics Data System (ADS)

Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

2016-08-01

The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m-3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere's near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth's surface with a global average reduction in shortwave radiation of 1.2 W m-2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR's CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed treatments. This study indicates that effective climate mitigation and emission control strategies are needed to prevent future health impact and ecosystem stress. Further, studies that are used to develop these strategies should use fully coupled models with sophisticated chemical and aerosol-interaction treatments that can provide a more realistic representation of the atmosphere.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash

The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality ismore » projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O 3 level and of 0.3 mg m 3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO 2, H 2O 2, and the nitrate radical and increasing the atmosphere’s near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O 3, and increases in CH 4 and VOCs. Increasing NO x and O 3 levels enhances the nitrogen and O 3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth’s surface with a global average reduction in shortwave radiation of 1.2 W m 2 . This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR’s CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed treatments. This study indicates that effective climate mitigation and emission control strategies are needed to prevent future health impact and ecosystem stress. Further, studies that are used to develop these strategies should use fully coupled models with sophisticated chemical and aerosol-interaction treatments that can provide a more realistic representation of the atmosphere.« less

Simulations of Tornadoes, Tropical Cyclones, MJOs, and QBOs, using GFDL's multi-scale global climate modeling system

NASA Astrophysics Data System (ADS)

Lin, Shian-Jiann; Harris, Lucas; Chen, Jan-Huey; Zhao, Ming

2014-05-01

A multi-scale High-Resolution Atmosphere Model (HiRAM) is being developed at NOAA/Geophysical Fluid Dynamics Laboratory. The model's dynamical framework is the non-hydrostatic extension of the vertically Lagrangian finite-volume dynamical core (Lin 2004, Monthly Wea. Rev.) constructed on a stretchable (via Schmidt transformation) cubed-sphere grid. Physical parametrizations originally designed for IPCC-type climate predictions are in the process of being modified and made more "scale-aware", in an effort to make the model suitable for multi-scale weather-climate applications, with horizontal resolution ranging from 1 km (near the target high-resolution region) to as low as 400 km (near the antipodal point). One of the main goals of this development is to enable simulation of high impact weather phenomena (such as tornadoes, thunderstorms, category-5 hurricanes) within an IPCC-class climate modeling system previously thought impossible. We will present preliminary results, covering a very wide spectrum of temporal-spatial scales, ranging from simulation of tornado genesis (hours), Madden-Julian Oscillations (intra-seasonal), topical cyclones (seasonal), to Quasi Biennial Oscillations (intra-decadal), using the same global multi-scale modeling system.

Affordances and Limitations of Immersive Participatory Augmented Reality Simulations for Teaching and Learning

NASA Astrophysics Data System (ADS)

Dunleavy, Matt; Dede, Chris; Mitchell, Rebecca

2009-02-01

The purpose of this study was to document how teachers and students describe and comprehend the ways in which participating in an augmented reality (AR) simulation aids or hinders teaching and learning. Like the multi-user virtual environment (MUVE) interface that underlies Internet games, AR is a good medium for immersive collaborative simulation, but has different strengths and limitations than MUVEs. Within a design-based research project, the researchers conducted multiple qualitative case studies across two middle schools (6th and 7th grade) and one high school (10th grade) in the northeastern United States to document the affordances and limitations of AR simulations from the student and teacher perspective. The researchers collected data through formal and informal interviews, direct observations, web site posts, and site documents. Teachers and students reported that the technology-mediated narrative and the interactive, situated, collaborative problem solving affordances of the AR simulation were highly engaging, especially among students who had previously presented behavioral and academic challenges for the teachers. However, while the AR simulation provided potentially transformative added value, it simultaneously presented unique technological, managerial, and cognitive challenges to teaching and learning.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene--A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight.

PubMed

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A; Abuzenadah, Adel M; Damanhouri, Ghazi A; Bajouh, Osama S; AlBasri, Samera F; Assiri, Mansour M; Beg, Mohd A

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene—A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight

PubMed Central

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A.; Abuzenadah, Adel M.; Damanhouri, Ghazi A.; Bajouh, Osama S.; AlBasri, Samera F.; Assiri, Mansour M.; Beg, Mohd A.

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use. PMID:26379041

Augmented Reality-Based Simulators as Discovery Learning Tools: An Empirical Study

ERIC Educational Resources Information Center

Ibáñez, María-Blanca; Di-Serio, Ángela; Villarán-Molina, Diego; Delgado-Kloos, Carlos

2015-01-01

This paper reports empirical evidence on having students use AR-SaBEr, a simulation tool based on augmented reality (AR), to discover the basic principles of electricity through a series of experiments. AR-SaBEr was enhanced with knowledge-based support and inquiry-based scaffolding mechanisms, which proved useful for discovery learning in…

Real-time simulations for automated rendezvous and capture

NASA Technical Reports Server (NTRS)

Cuseo, John A.

1991-01-01

Although the individual technologies for automated rendezvous and capture (AR&C) exist, they have not yet been integrated to produce a working system in the United States. Thus, real-time integrated systems simulations are critical to the development and pre-flight demonstration of an AR&C capability. Real-time simulations require a level of development more typical of a flight system compared to purely analytical methods, thus providing confidence in derived design concepts. This presentation will describe Martin Marietta's Space Operations Simulation (SOS) Laboratory, a state-of-the-art real-time simulation facility for AR&C, along with an implementation for the Satellite Servicer System (SSS) Program.

Development and application of a mechanistic model to estimate emission of nitrous oxide from UK agriculture

NASA Astrophysics Data System (ADS)

Brown, L.; Syed, B.; Jarvis, S. C.; Sneath, R. W.; Phillips, V. R.; Goulding, K. W. T.; Li, C.

A mechanistic model of N 2O emission from agricultural soil (DeNitrification-DeComposition—DNDC) was modified for application to the UK, and was used as the basis of an inventory of N 2O emission from UK agriculture in 1990. UK-specific input data were added to DNDC's database and the ability to simulate daily C and N inputs from grazing animals and applied animal waste was added to the model. The UK version of the model, UK-DNDC, simulated emissions from 18 different crop types on the 3 areally dominant soils in each county. Validation of the model at the field scale showed that predictions matched observations well. Emission factors for the inventory were calculated from estimates of N 2O emission from UK-DNDC, in order to maintain direct comparability with the IPCC approach. These, along with activity data, were included in a transparent spreadsheet format. Using UK-DNDC, the estimate of N 2O-N emission from UK current agricultural practice in 1990 was 50.9 Gg. This total comprised 31.7 Gg from the soil sector, 5.9 Gg from animals and 13.2 Gg from the indirect sector. The range of this estimate (using the range of soil organic C for each soil used) was 30.5-62.5 Gg N. Estimates of emissions in each sector were compared to those calculated using the IPCC default methodology. Emissions from the soil and indirect sectors were smaller with the UK-DNDC approach than with the IPCC methodology, while emissions from the animal sector were larger. The model runs suggested a relatively large emission from agricultural land that was not attributable to current agricultural practices (33.8 Gg in total, 27.4 Gg from the soil sector). This 'background' component is partly the result of historical agricultural land use. It is not normally included in inventories of emission, but would increase the total emission of N 2O-N from agricultural land in 1990 to 78.3 Gg.

Direct Simulation Monte Carlo Application of the Three Dimensional Forced Harmonic Oscillator Model

DTIC Science & Technology

2017-12-07

quasi -classical scattering theory [3,4] or trajectory [5] calculations, semiclassical, as well as close-coupled [6,7] or full [8] quantum mechanical...the quasi -classical trajectory (QCT) calculations approach for ab initio modeling of collision processes. The DMS method builds on an earlier work...nu ar y 30 , 2 01 8 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /1 .T 52 28 to directly use quasi -classical or quantum mechanic

U.S. ozone air quality under changing climate and anthropogenic emissions.

PubMed

Racherla, Pavan N; Adams, Peter J

2009-02-01

We examined future ozone (O3) air quality in the United States (U.S.) under changing climate and anthropogenic emissions worldwide by performing global climate-chemistry simulations, utilizing various combinations of present (1990s) and future (Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 2050s) climates, and present and future (2050s; IPCC SRES A2 and B1) anthropogenic emissions. The A2 climate scenario is employed here because it lies at the upper extreme of projected climate change for the 21st century. To examine the sensitivity of U.S. O3 to regional emissions increases (decreases), the IPCC SRES A2 and B1 scenarios, which have overall higher and lower O3-precursor emissions for the U.S., respectively, have been chosen. We find that climate change, by itself, significantly worsens the severity and frequency of high-O3 events ("episodes") over most locations in the U.S., with relatively small changes in average O3 air quality. These high-O3 increases due to climate change alone will erode moderately the gains made under a U.S. emissions reduction scenario (e.g., B1). The effect of climate change on high- and average-O3 increases with anthropogenic emissions. Insofar as average O3 air quality is concerned, changes in U.S. anthropogenic emissions will play the most important role in attaining (or not) near-term U.S. O3 air quality standards. However, policy makers must plan appropriately for O3 background increases due to projected increases in global CH4 abundance and non-U.S. anthropogenic emissions, as well as potential local enhancements that they could cause. These findings provide strong incentives for more-than-planned emissions reductions at locations that are currently O3-nonattainment.

Aerosol–climate interactions in the Norwegian Earth System Model – NorESM1-M

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkevåg, A.; Iversen, T.; Seland, Ø.

2013-01-01

The objective of this study is to document and evaluate recent changes and updates to the module for aerosols and aerosol–cloud–radiation interactions in the atmospheric module CAM4-Oslo of the core version of the Norwegian Earth System Model (NorESM), NorESM1-M. Particular attention is paid to the role of natural organics, sea salt, and mineral dust in determining the gross aerosol properties as well as the anthropogenic contribution to these properties and the associated direct and indirect radiative forcing. The aerosol module is extended from earlier versions that have been published, and includes life-cycling of sea salt, mineral dust, particulate sulphate, blackmore » carbon, and primary and secondary organics. The impacts of most of the numerous changes since previous versions are thoroughly explored by sensitivity experiments. The most important changes are: modified prognostic sea salt emissions; updated treatment of precipitation scavenging and gravitational settling; inclusion of biogenic primary organics and methane sulphonic acid (MSA) from oceans; almost doubled production of land-based biogenic secondary organic aerosols (SOA); and increased ratio of organic matter to organic carbon (OM/OC) for biomass burning aerosols from 1.4 to 2.6. Compared with in situ measurements and remotely sensed data, the new treatments of sea salt and dust aerosols give smaller biases in near-surface mass concentrations and aerosol optical depth than in the earlier model version. The model biases for mass concentrations are approximately unchanged for sulphate and BC. The enhanced levels of modeled OM yield improved overall statistics, even though OM is still underestimated in Europe and overestimated in North America. The global anthropogenic aerosol direct radiative forcing (DRF) at the top of the atmosphere has changed from a small positive value to -0.08 W m-2 in CAM4-Oslo. The sensitivity tests suggest that this change can be attributed to the new treatment of biomass burning aerosols and gravitational settling. Although it has not been a goal in this study, the new DRF estimate is closer both to the median model estimate from the AeroCom intercomparison and the best estimate in IPCC AR4. Estimated DRF at the ground surface has increased by ca. 60%, to -1.89 W m-2. We show that this can be explained by new emission data and omitted mixing of constituents between updrafts and downdrafts in convective clouds. The increased abundance of natural OM and the introduction of a cloud droplet spectral dispersion formulation are the most important contributions to a considerably decreased estimate of the indirect radiative forcing (IndRF). The IndRF is also found to be sensitive to assumptions about the coating of insoluble aerosols by sulphate and OM. The IndRF of -1.2 W m-2, which is closer to the IPCC AR4 estimates than the previous estimate of -1.9 W m-2, has thus been obtained without imposing unrealistic artificial lower bounds on cloud droplet number concentrations.« less

Continuously on-­going regional climate hindcast simulations for impact applications

NASA Astrophysics Data System (ADS)

Anders, Ivonne; Piringer, Martin; Kaufmann, Hildegard; Knauder, Werner; Resch, Gernot; Andre, Konrad

2017-04-01

Observational data for e.g. temperature, precipitation, radiation, or wind are often used as meteorological forcing for different impact models, like e.g. crop models, urban models, economic models and energy system models. To assess a climate signal, the time period covered by the observation is often too short, they have gaps in between, and are inhomogeneous over time, due to changes in the measurements itself or in the near surrounding. Thus output from global and regional climate models can close the gap and provide homogeneous and physically consistent time series of meteorological parameters. CORDEX evaluation runs performed for the IPCC-AR5 provide a good base for the regional scale. However, with respect to climate services, continuously on-going hindcast simulations are required for regularly updated applications. The Climate Research group at the national Austrian weather service, ZAMG, is focusing on high mountain regions and, especially on the Alps. The hindcast-simulation performed with the regional climate model COSMO-CLM is forced by ERAinterim and optimized for the Alpine Region. The simulation available for the period of 1979-2015 in a spatial resolution of about 10km is prolonged ongoing and fullfils the customer's needs with respect of output variables, levels, intervals and statistical measures. One of the main tasks is to capture strong precipitation events which often occur during summer when low pressure systems develop over the Golf of Genoa, moving to the Northeast. This leads to floods and landslide events in Austria, Czech Republic and Germany. Such events are not sufficiently represented in the CORDEX-evaluation runs. ZAMG use high quality gridded precipitation and temperature data for the Alpine Region (1-6km) to evaluate the model performance. Data is provided e.g. to hydrological modellers (high water, low water), but also to assess icing capability of infrastructure or the calculation the separation distances between livestock farming and residential area.

AgMIP: Next Generation Models and Assessments

NASA Astrophysics Data System (ADS)

Rosenzweig, C.

2014-12-01

Next steps in developing next-generation crop models fall into several categories: significant improvements in simulation of important crop processes and responses to stress; extension from simplified crop models to complex cropping systems models; and scaling up from site-based models to landscape, national, continental, and global scales. Crop processes that require major leaps in understanding and simulation in order to narrow uncertainties around how crops will respond to changing atmospheric conditions include genetics; carbon, temperature, water, and nitrogen; ozone; and nutrition. The field of crop modeling has been built on a single crop-by-crop approach. It is now time to create a new paradigm, moving from 'crop' to 'cropping system.' A first step is to set up the simulation technology so that modelers can rapidly incorporate multiple crops within fields, and multiple crops over time. Then the response of these more complex cropping systems can be tested under different sustainable intensification management strategies utilizing the updated simulation environments. Model improvements for diseases, pests, and weeds include developing process-based models for important diseases, frameworks for coupling air-borne diseases to crop models, gathering significantly more data on crop impacts, and enabling the evaluation of pest management strategies. Most smallholder farming in the world involves integrated crop-livestock systems that cannot be represented by crop modeling alone. Thus, next-generation cropping system models need to include key linkages to livestock. Livestock linkages to be incorporated include growth and productivity models for grasslands and rangelands as well as the usual annual crops. There are several approaches for scaling up, including use of gridded models and development of simpler quasi-empirical models for landscape-scale analysis. On the assessment side, AgMIP is leading a community process for coordinated contributions to IPCC AR6 that involves the key modeling groups from around the world including North America, Europe, South America, Sub-Saharan Africa, South Asia, East Asia, and Australia and Oceania. This community process will lead to mutually agreed protocols for coordinated global and regional assessments.

Precise measurement of the angular correlation parameter aβν in the β decay of 35Ar with LPCTrap

NASA Astrophysics Data System (ADS)

Fabian, X.; Ban, G.; Boussaïd, R.; Breitenfeldt, M.; Couratin, C.; Delahaye, P.; Durand, D.; Finlay, P.; Fléchard, X.; Guillon, B.; Lemière, Y.; Leredde, A.; Liénard, E.; Méry, A.; Naviliat-Cuncic, O.; Pierre, E.; Porobic, T.; Quéméner, G.; Rodríguez, D.; Severijns, N.; Thomas, J. C.; Van Gorp, S.

2014-03-01

Precise measurements in the β decay of the 35Ar nucleus enable to search for deviations from the Standard Model (SM) in the weak sector. These measurements enable either to check the CKM matrix unitarity or to constrain the existence of exotic currents rejected in the V-A theory of the SM. For this purpose, the β-ν angular correlation parameter, aβν, is inferred from a comparison between experimental and simulated recoil ion time-of-flight distributions following the quasi-pure Fermi transition of 35Ar1+ ions confined in the transparent Paul trap of the LPCTrap device at GANIL. During the last experiment, 1.5×106 good events have been collected, which corresponds to an expected precision of less than 0.5% on the aβν value. The required simulation is divided between the use of massive GPU parallelization and the GEANT4 toolkit for the source-cloud kinematics and the tracking of the decay products.

Directing driver attention with augmented reality cues

PubMed Central

Rusch, Michelle L.; Schall, Mark C.; Gavin, Patrick; Lee, John D.; Dawson, Jeffrey D.; Vecera, Shaun; Rizzo, Matthew

2013-01-01

This simulator study evaluated the effects of augmented reality (AR) cues designed to direct the attention of experienced drivers to roadside hazards. Twenty-seven healthy middle-aged licensed drivers with a range of attention capacity participated in a 54 mile (1.5 hour) drive in an interactive fixed-base driving simulator. Each participant received AR cues to potential roadside hazards in six simulated straight (9 mile long) rural roadway segments. Drivers were evaluated on response time for detecting a potentially hazardous event, detection accuracy for target (hazard) and non-target objects, and headway with respect to the hazards. Results showed no negative outcomes associated with interference. AR cues did not impair perception of non-target objects, including for drivers with lower attentional capacity. Results showed near significant response time benefits for AR cued hazards. AR cueing increased response rate for detecting pedestrians and warning signs but not vehicles. AR system false alarms and misses did not impair driver responses to potential hazards. PMID:24436635

Climate-suitable planting as a strategy for maintaining forest productivity and functional diversity.

PubMed

Duveneck, Matthew J; Scheller, Robert M

2015-09-01

Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000-2100) at a 2-ha cell resolution and five-year time steps within two landscapes in the Great Lakes region (northeastern Minnesota and northern lower Michigan, USA). We compared current climate to low- and high-emission futures. We simulated a low-emission climate future with the Intergovernmental Panel on Climate Change (IPCC) 2007 B1 emission scenario and the Parallel Climate Model Global Circulation Model (GCM). We simulated a high-emission climate future with the IPCC A1FI emission scenario and the Geophysical Fluid Dynamics Laboratory (GFDL) GCM. We compared current forest management practices (business-as-usual) to CSP management. In the CSP scenario, we simulated a target planting of 5.28% and 4.97% of forested area per five-year time step in the Minnesota and Michigan landscapes, respectively. We found that simulated CSP species successfully established in both landscapes under all climate scenarios. The presence of CSP species generally increased simulated aboveground biomass. Species diversity increased due to CSP; however, the effect on functional diversity was variable. Because the planted species were functionally similar to many native species, CSP did not result in a consistent increase nor decrease in functional diversity. These results provide an assessment of the potential efficacy and limitations of CSP management. These results have management implications for sites where diversity and productivity are expected to decline. Future efforts to restore a specific species or forest type may not be possible, but CSP may sustain a more general ecosystem service (e.g., aboveground biomass).

Assessing climate change impacts, benefits of mitigation, and uncertainties on major global forest regions under multiple socioeconomic and emissions scenarios

DOE PAGES

Kim, John B.; Monier, Erwan; Sohngen, Brent; ...

2017-03-28

We analyze a set of simulations to assess the impact of climate change on global forests where MC2 dynamic global vegetation model (DGVM) was run with climate simulations from the MIT Integrated Global System Model-Community Atmosphere Model (IGSM-CAM) modeling framework. The core study relies on an ensemble of climate simulations under two emissions scenarios: a business-as-usual reference scenario (REF) analogous to the IPCC RCP8.5 scenario, and a greenhouse gas mitigation scenario, called POL3.7, which is in between the IPCC RCP2.6 and RCP4.5 scenarios, and is consistent with a 2 °C global mean warming from pre-industrial by 2100. Evaluating the outcomesmore » of both climate change scenarios in the MC2 model shows that the carbon stocks of most forests around the world increased, with the greatest gains in tropical forest regions. Temperate forest regions are projected to see strong increases in productivity offset by carbon loss to fire. The greatest cost of mitigation in terms of effects on forest carbon stocks are projected to be borne by regions in the southern hemisphere. We compare three sources of uncertainty in climate change impacts on the world’s forests: emissions scenarios, the global system climate response (i.e. climate sensitivity), and natural variability. The role of natural variability on changes in forest carbon and net primary productivity (NPP) is small, but it is substantial for impacts of wildfire. Forest productivity under the REF scenario benefits substantially from the CO 2 fertilization effect and that higher warming alone does not necessarily increase global forest carbon levels. Finally, our analysis underlines why using an ensemble of climate simulations is necessary to derive robust estimates of the benefits of greenhouse gas mitigation. It also demonstrates that constraining estimates of climate sensitivity and advancing our understanding of CO 2 fertilization effects may considerably reduce the range of projections.« less

Assessing climate change impacts, benefits of mitigation, and uncertainties on major global forest regions under multiple socioeconomic and emissions scenarios

NASA Astrophysics Data System (ADS)

Kim, John B.; Monier, Erwan; Sohngen, Brent; Pitts, G. Stephen; Drapek, Ray; McFarland, James; Ohrel, Sara; Cole, Jefferson

2017-04-01

We analyze a set of simulations to assess the impact of climate change on global forests where MC2 dynamic global vegetation model (DGVM) was run with climate simulations from the MIT Integrated Global System Model-Community Atmosphere Model (IGSM-CAM) modeling framework. The core study relies on an ensemble of climate simulations under two emissions scenarios: a business-as-usual reference scenario (REF) analogous to the IPCC RCP8.5 scenario, and a greenhouse gas mitigation scenario, called POL3.7, which is in between the IPCC RCP2.6 and RCP4.5 scenarios, and is consistent with a 2 °C global mean warming from pre-industrial by 2100. Evaluating the outcomes of both climate change scenarios in the MC2 model shows that the carbon stocks of most forests around the world increased, with the greatest gains in tropical forest regions. Temperate forest regions are projected to see strong increases in productivity offset by carbon loss to fire. The greatest cost of mitigation in terms of effects on forest carbon stocks are projected to be borne by regions in the southern hemisphere. We compare three sources of uncertainty in climate change impacts on the world’s forests: emissions scenarios, the global system climate response (i.e. climate sensitivity), and natural variability. The role of natural variability on changes in forest carbon and net primary productivity (NPP) is small, but it is substantial for impacts of wildfire. Forest productivity under the REF scenario benefits substantially from the CO2 fertilization effect and that higher warming alone does not necessarily increase global forest carbon levels. Our analysis underlines why using an ensemble of climate simulations is necessary to derive robust estimates of the benefits of greenhouse gas mitigation. It also demonstrates that constraining estimates of climate sensitivity and advancing our understanding of CO2 fertilization effects may considerably reduce the range of projections.

Assessing climate change impacts, benefits of mitigation, and uncertainties on major global forest regions under multiple socioeconomic and emissions scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, John B.; Monier, Erwan; Sohngen, Brent

We analyze a set of simulations to assess the impact of climate change on global forests where MC2 dynamic global vegetation model (DGVM) was run with climate simulations from the MIT Integrated Global System Model-Community Atmosphere Model (IGSM-CAM) modeling framework. The core study relies on an ensemble of climate simulations under two emissions scenarios: a business-as-usual reference scenario (REF) analogous to the IPCC RCP8.5 scenario, and a greenhouse gas mitigation scenario, called POL3.7, which is in between the IPCC RCP2.6 and RCP4.5 scenarios, and is consistent with a 2 °C global mean warming from pre-industrial by 2100. Evaluating the outcomesmore » of both climate change scenarios in the MC2 model shows that the carbon stocks of most forests around the world increased, with the greatest gains in tropical forest regions. Temperate forest regions are projected to see strong increases in productivity offset by carbon loss to fire. The greatest cost of mitigation in terms of effects on forest carbon stocks are projected to be borne by regions in the southern hemisphere. We compare three sources of uncertainty in climate change impacts on the world’s forests: emissions scenarios, the global system climate response (i.e. climate sensitivity), and natural variability. The role of natural variability on changes in forest carbon and net primary productivity (NPP) is small, but it is substantial for impacts of wildfire. Forest productivity under the REF scenario benefits substantially from the CO 2 fertilization effect and that higher warming alone does not necessarily increase global forest carbon levels. Finally, our analysis underlines why using an ensemble of climate simulations is necessary to derive robust estimates of the benefits of greenhouse gas mitigation. It also demonstrates that constraining estimates of climate sensitivity and advancing our understanding of CO 2 fertilization effects may considerably reduce the range of projections.« less

Multisite experimental cost study of intensive psychiatric community care.

PubMed

Rosenheck, R; Neale, M; Leaf, P; Milstein, R; Frisman, L

1995-01-01

A 2-year experimental cost study of 10 Intensive Psychiatric Community Care (IPCC) programs was conducted at Department of Veterans Affairs (VA) medical centers in the Northeast. High hospital users were randomly assigned to either IPCC (n = 454) or standard VA care (n = 419) at four neuropsychiatric (NP) and six general medical and surgical (GMS) hospitals. National computerized data were used to track all VA health care service usage and costs for 2 years following program entry. At 9 of the 10 sites, IPCC treatment resulted in reduced inpatient service usage. Overall, for IPCC patients compared with control patients, average inpatient usage was 89 days (33%) less while average cost per patient (for IPCC inpatient, and outpatient services) was $15,556 (20%) less. Additionally, costs for IPCC patients compared with control patients were $33,295 (29%) less at NP sites but were $6,273 (15%) greater at GMS sites. At both NP and GMS sites, costs were lower for IPCC patients in two subgroups: veterans over age 45 and veterans with high levels of inpatient service use before program entry. No interaction was noted between the impact of IPCC on costs and other clinical or sociodemographic characteristics. Similarly, no linear relationship was observed between the intensity of IPCC services and the impact of IPCC on VA costs, although the two sites that did not fully implement the IPCC program had the poorest results. With these sites excluded, the total cost of care for IPCC patients at GMS sites was $579 (3%) more per year than that for the control patients.

The Age of the Moon As Told By Dynamics and Asteroidal Meteorites

NASA Astrophysics Data System (ADS)

Bottke, W. F.; Marchi, S.; Vokrouhlicky, D.

2013-12-01

The Moon likely formed as a result of a collision between a large protoplanet and the early Earth. A long-standing mystery, however, is precisely when this giant impact (GI) took place. The conventional wisdom, based on both planet formation models and age estimates of ancient lunar samples, is that the GI occurred many tens of My after the formation of CAIs (~4.45-4.53 Ga). New work on ferroan anothosites by Borg et al. (2011; Nature), however, indicates the Moon may have formed ~200 My after CAIs (4.36 Ga). If true, our understanding of solar system evolution and lunar origin will require drastic revisions. The problem is that testing the claims of Borg et al. (2011) is difficult; ancient lunar samples are both rare and hard to date, while current planet formation models have their issues (e.g., they cannot yet make Mars or the asteroid belt with all of their observed properties). This prompted us to examine a novel method to calculate the timing of the GI. Consider that the GI, probably the largest collision to ever take place in the inner solar system, should have produced lots of debris. Numerical hydrocode simulations of the GI by R. Canup show that, on average, 5-10% of an Earth-mass escapes the Earth-Moon system as ejecta; this is equivalent to 100-200 times the mass of the asteroid belt. Our dynamical simulations show this material spreads rapidly across the inner solar system over tens of My, with most bodies going away by hitting the Earth (20-40%), Venus (20-40%), the Sun, or by being ejected out of the Solar System via an encounter with Jupiter. Before they are eliminated, however, a substantial fraction of ejecta reach orbits that allow them to slam into primordial main belt asteroids at high velocities (> 10 km/s). These kinds of impacts are particularly good at heating target material and thereby creating Ar-Ar shock degassing ages. Using the formalism of Marchi, Bottke et al. (2013; Nature Geosci.), we found that over a ~100 My interval, high velocity ejecta from the GI should have made numerous small craters on D > 100 km diameter asteroids in the main belt. If this heated material was ever delivered to Earth in the form of meteorites, it would produce an abundance of Ar-Ar ages at these times. Overall, we estimate the volume of material heated to high temperatures on main belt asteroids was at least several times that made by Late Heavy Bombardment projectiles between 3.5-4.1 Ga. Next, we tried to place these putative Ar-Ar events from the GI in time by examining the record of ancient Ar-Ar ages for various stony meteorite classes (i.e., H, L, LL, HED, EH, EL, EM, R, and AL; Bogard 2011; Chem. Erde). We found that (i) numerous ages can be found across all meteorite classes between 4.45-4.53 Ga and (ii) almost none can be found between ~4.1-4.4 Ga. We infer that the GI took place in interval (i) and not at 4.36 Ga as suggested by Borg et al. (2011); if it had, we would see numerous Ar-Ar ages there. We speculate that the source of the lunar magmatic events recorded at ~4.36 Ga may instead have been triggered by a massive impact event, possibly the formation of South Pole-Aitken basin, as postulated by Borg et al. (2011). Interestingly, this age agrees with the 4.33-4.39 Ga age derived for SPA by Morbidelli et al. (2012; EPSL) using their new lunar chronology and new measurements of the spatial density of craters found on SPA.

Implications of global warming for regional climate and water resources of tropical islands: Case studies over Sri Lanka and Puerto Rico

NASA Astrophysics Data System (ADS)

Mawalagedara, R.; Kumar, D.; Oglesby, R. J.; Ganguly, A. R.

2013-12-01

The IPCC AR4 identifies small islands as particularly vulnerable to climate change. Here we consider the cases of two tropical islands: Sri Lanka in the Indian Ocean and Puerto Rico in the Caribbean. The islands share a predominantly tropical climate with diverse topography and hence significant spatial variability of regional climate. Seasonal variability in temperatures is relatively small, but spatial variations can be large owing to topography. Precipitation mechanisms and patterns over the two islands are different however. Sri Lanka receives a majority of the annual rainfall from the summer and winter monsoons, with convective rainfall dominating in the inter-monsoon period. Rainfall generating mechanisms over Puerto Rico can range from orographic lifting, disturbances embedded in Easterly waves and synoptic frontal systems. Here we compare the projected changes in the regional and seasonal means and extremes of temperature and precipitation over the two islands during the middle of this century with the present conditions. Two 5-year regional climate model runs for each region, representing the present (2006-2010) and future (2056-2060) conditions, are performed using the Weather Research and Forecasting model with the lateral boundary conditions provided using the output from CCSM4 RCP8.5 greenhouse gas emissions pathway simulation from the CMIP5 ensemble. The consequences of global warming for water resources and the overall economy are examined. While both economies have substantial contributions from tourism, there are major differences: The agricultural sector is much more important over Sri Lanka compared to Puerto Rico, while the latter exhibits no recent growth in population or in urbanization trends unlike the former. Policy implications for water sustainability and security are discussed, which highlight how despite the differences, certain lessons learned may generalize across the two relatively small tropical islands, which in turn have diverse economic, infrastructural, and societal constraints.

Grassland production under global change scenarios for New Zealand pastoral agriculture

NASA Astrophysics Data System (ADS)

Keller, E. D.; Baisden, W. T.; Timar, L.; Mullan, B.; Clark, A.

2014-05-01

We adapt and integrate the Biome-BGC and Land Use in Rural New Zealand (LURNZ) models to simulate pastoral agriculture and to make land-use change, intensification and climate change scenario projections of New Zealand's pasture production at time slices centred on 2020, 2050 and 2100, with comparison to a present-day baseline. Biome-BGC model parameters are optimised for pasture production in both dairy and sheep/beef farm systems, representing a new application of the Biome-BGC model. Results show up to a 10% increase in New Zealand's national pasture production in 2020 under intensification and a 1-2% increase by 2050 from economic factors driving land-use change. Climate change scenarios using statistically downscaled global climate models (GCMs) from the IPCC Fourth Assessment Report (AR4) also show national increases of 1-2% in 2050, with significant regional variations. Projected out to 2100, however, these scenarios are more sensitive to the type of pasture system and the severity of warming: dairy systems show an increase in production of 4% under mild change but a decline of 1% under a more extreme case, whereas sheep/beef production declines in both cases by 3% and 13%, respectively. Our results suggest that high-fertility systems such as dairying could be more resilient under future change, with dairy production increasing or only slightly declining in all of our scenarios. These are the first national-scale estimates using a model to evaluate the joint effects of climate change, CO2 fertilisation and N-cycle feedbacks on New Zealand's unique pastoral production systems that dominate the nation's agriculture and economy. Model results emphasize that CO2 fertilisation and N cycle feedback effects are responsible for meaningful differences in agricultural systems. More broadly, we demonstrate that our model output enables analysis of Decoupled Land-Use Change Scenarios (DLUCS): the Biome-BGC data products at a national or regional level can be re-sampled quickly and cost-effectively for specific land-use change scenarios and future projections.

Making climate change projections relevant to water management: opportunities and challenges in the Colorado River basin (Invited)

NASA Astrophysics Data System (ADS)

Vano, J. A.

2013-12-01

By 2007, motivated by the ongoing drought and release of new climate model projections associated with the IPCC AR4 report, multiple independent studies had made estimates of future Colorado River streamflow. Each study had a unique approach, and unique estimate for the magnitude for mid-21st century streamflow change ranging from declines of only 6% to declines of as much as 45%. The differences among studies provided for interesting scientific debates, but to many practitioners this appeared to be just a tangle of conflicting predictions, leading to the question 'why is there such a wide range of projections of impacts of future climate change on Colorado River streamflow, and how should this uncertainty be interpreted?' In response, a group of scientists from academic and federal agencies, brought together through a NOAA cross-RISA project, set forth to identify the major sources of disparities and provide actionable science and guidance for water managers and decision makers. Through this project, four major sources of disparities among modeling studies were identified that arise from both methodological and model differences. These differences, in order of importance, are: (1) the Global Climate Models (GCMs) and emission scenarios used; (2) the ability of land surface hydrology and atmospheric models to simulate properly the high elevation runoff source areas; (3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and (4) the methods used to statistically downscale GCM scenarios. Additionally, reconstructions of pre-instrumental streamflows provided further insights about the greatest risk to Colorado River streamflow of a multi-decadal drought, like those observed in paleo reconstructions, exacerbated by a steady reduction in flows due to climate change. Within this talk I will provide an overview of these findings and insights into the opportunities and challenges encountered in the process of striving to make climate change projections more useful to water managers and decision makers.

Molecular modeling of the effects of 40Ar recoil in illite particles on their K-Ar isotope dating

NASA Astrophysics Data System (ADS)

Szczerba, Marek; Derkowski, Arkadiusz; Kalinichev, Andrey G.; Środoń, Jan

2015-06-01

The radioactive decay of 40K to 40Ar is the basis of isotope age determination of micaceous clay minerals formed during diagenesis. The difference in K-Ar ages between fine and coarse grained illite particles has been interpreted using detrital-authigenic components system, its crystallization history or post-crystallization diffusion. Yet another mechanism should also be considered: natural 40Ar recoil. Whether this recoil mechanism can result in a significant enough loss of 40Ar to provide observable decrease of K-Ar age of the finest illite crystallites at diagenetic temperatures - is the primary objective of this study which is based on molecular dynamics (MD) computer simulations. All the simulations were performed for the same kinetic energy (initial velocity) of the 40Ar atom, but for varying recoil angles that cover the entire range of their possible values. The results show that 40Ar recoil can lead to various deformations of the illite structure, often accompanied by the displacement of OH groups or breaking of the Si-O bonds. Depending on the recoil angle, there are four possible final positions of the 40Ar atom with respect to the 2:1 layer at the end of the simulation: it can remain in the interlayer space or end up in the closest tetrahedral, octahedral or the opposite tetrahedral sheet. No simulation angles were found for which the 40Ar atom after recoil passes completely through the 2:1 layer. The energy barrier for 40Ar passing through the hexagonal cavity from the tetrahedral sheet into the interlayer was calculated to be 17 kcal/mol. This reaction is strongly exothermic, therefore there is almost no possibility for 40Ar to remain in the tetrahedral sheet of the 2:1 layer over geological time periods. It will either leave the crystal, if close enough to the edge, or return to the interlayer space. On the other hand, if 40Ar ends up in the octahedral sheet after recoil, a substantially higher energy barrier of 55 kcal/mol prevents it from leaving the TOT layer over geological time. Based on the results of MD simulations, the estimates of the potential effect of 40Ar recoil on the K-Ar dating of illite show that some of 40Ar is lost and the loss is substantially dependent on the crystallite dimensions. The 40Ar loss can vary from 10% for the finest crystallites (two 2:1 layers thickness and <0.02 μm in diameter) to close to zero for the thickest and largest (in the ab plane) ones. Because the decrease of the K-Ar estimated age is approximately proportional to the 40Ar loss, the finer crystallites show lower apparent age than the coarser ones, although the age of crystallization is assumed equal for all the crystallites. From the model it is also clear that the lack of K removal from illite fringes (potentially Ar-free) strongly increases the apparent age differences among crystallites of different size.

The use of augmented reality glasses in central line simulation: "see one, simulate many, do one competently, and teach everyone".

PubMed

Huang, Cynthia Y; Thomas, Jonathan B; Alismail, Abdullah; Cohen, Avi; Almutairi, Waleed; Daher, Noha S; Terry, Michael H; Tan, Laren D

2018-01-01

The aim of this study was to investigate the feasibility of using augmented reality (AR) glasses in central line simulation by novice operators and compare its efficacy to standard central line simulation/teaching. This was a prospective randomized controlled study enrolling 32 novice operators. Subjects were randomized on a 1:1 basis to either simulation using the augmented virtual reality glasses or simulation using conventional instruction. The study was conducted in tertiary-care urban teaching hospital. A total of 32 adult novice central line operators with no visual or auditory impairments were enrolled. Medical doctors, respiratory therapists, and sleep technicians were recruited from the medical field. The mean time for AR placement in the AR group was 71±43 s, and the time to internal jugular (IJ) cannulation was 316±112 s. There was no significant difference in median (minimum, maximum) time (seconds) to IJ cannulation for those who were in the AR group and those who were not (339 [130, 550] vs 287 [35, 475], p =0.09), respectively. There was also no significant difference between the two groups in median total procedure time (524 [329, 792] vs 469 [198, 781], p =0.29), respectively. There was a significant difference in the adherence level between the two groups favoring the AR group ( p =0.003). AR simulation of central venous catheters in manikins is feasible and efficacious in novice operators as an educational tool. Future studies are recommended in this area as it is a promising area of medical education.

Sensitivity of Boreal-Summer Circulation and Precipitation to Atmospheric Aerosols in Selected Regions: Part I Africa and India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sud, Yogesh C.; Wilcox, Eric; Lau, William K.

2009-10-23

Version-4 of the Goddard Earth Observing System (GEOS-4) General Circulation Model (GCM) was employed to assess the influence of potential changes in aerosols on the regional circulation, ambient temperatures, and precipitation in four selected regions: India and Africa (current paper), as well as North and South America (companion paper). Ensemble-simulations were carried out with the GCM to assess the aerosol direct and indirect effects, hereafter ADE and AIE. Each simulation was started from the NCEP-analyzed initial conditions for May 1 and was integrated through May-June-July-August of each year: 1982-1987 to provide an ensemble set of six simulations. In the firstmore » set, called the baseline experiment (#1), climatological aerosols were prescribed. The next two experiments (#2 and #3) had two sets of simulations each: one with 2X and another with 1/2X the climatological aerosols over each of the four selected regions. In experiment#2, the anomaly regions were advectively restricted (AR), i.e., the large-scale prognostic fields outside the aerosol anomaly regions were prescribed while in experiment#3, the anomaly regions were advectively Interactive (AI) as is the case in a normal GCM integrations, but with the same aerosols anomalies as in experiment #2. Intercomparisons of circulation, diabatic heating, and precipitation difference fields showed large disparities among the AR and AI simulations, which raised serious questions about the AR assumption, commonly invoked in regional climate simulation studies. Consequently AI simulation mode was chosen for the subsequent studies. Two more experiments (#4 and #5) were performed in the AI mode in which ADE and AIE were activated one at a time. The results showed that ADE and AIE work in concert to make the joint influences larger than sum of each acting alone. Moreover, the ADE and AIE influences were vastly different for the Indian and Africa regions, which suggest an imperative need to include them rationally in climate models. We also found that the aerosol induced increase of tropical cirrus clouds would potentially offset any cirrus thinning that may occur due to global warming in response to CO2 increase.« less

Gas-phase evolution of Ar/H2O and Ar/CH4 dielectric barrier discharge plasmas

NASA Astrophysics Data System (ADS)

Barni, Ruggero; Riccardi, Claudia

2018-04-01

We present some experimental results of an investigation aimed to hydrogen production with atmospheric pressure plasmas, based on the use of dielectric barrier discharges, fed with a high-voltage alternating signal at frequency 30-50 kHz, in mixtures of methane or water vapor diluted in argon. The plasma gas-phase of the discharge was investigated by means of optical and electrical diagnostics. The emission spectra of the discharges was measured with a wide band spectrometer and a photosensor module, based on a photomultiplier tube. A Rogowski coil allowed to measure the electric current flowing into the circuit and a high voltage probe was employed for evaluating the voltage at the electrodes. The analysis of the signals of voltage and current shows the presence of microdischarges between the electrodes in two alternating phases during the period of oscillation of the applied voltage. The hydrogen concentration in the gaseous mixture was measured too. Besides this experimental campaign, we present also results from a numerical modeling of chemical kinetics in the gas-phase of Ar/H2O and Ar/CH4 plasmas. The simulations were conducted under conditions of single discharge to study the evolution of the system and of fixed frequency repeated discharging. In particular in Ar/H2O mixtures we could study the evolution from early atomic dissociation in the discharge, to longer time scales, when chemical reactions take place producing an increase of the density of species such as OH, H2O2 and subsequently of H and H2. The results of numerical simulations provide some insights into the evolution happening in the plasma gas-phase during the hydrogen reforming process.

Projected Changes to Streamflow Characteristics in Quebec Basins as Simulated by the Canadian Regional Climate Model (CRCM4)

NASA Astrophysics Data System (ADS)

Huziy, O.; Sushama, L.; Khaliq, M.; Lehner, B.; Laprise, R.; Roy, R.

2011-12-01

According to the Intergovernmental Panel on Climate Change (IPCC, 2007), an intensification of the global hydrological cycle and increase in precipitation for some regions around the world, including the northern mid- to high-latitudes, is expected in future climate. This will have an impact on mean and extreme flow characteristics, which need to be assessed for better development of adaptation strategies. Analysis of the mean and extreme streamflow characteristics for Quebec (North-eastern Canada) basins in current climate and their projected changes in future climate are assessed using a 10 member ensemble of current (1970 - 1999) and future (2041 - 2070) Canadian RCM (CRCM4) simulations. Validation of streamflow characteristics, performed by comparing modeled values with those observed, available from the Centre d'expertise hydrique du Quebec (CEHQ) shows that the model captures reasonably well the high flows. Results suggest increase in mean and 10 year return levels of 1 day high flows, which appear significant for most of the northern basins.

Stabilizing IkappaBalpha by "consensus" design.

PubMed

Ferreiro, Diego U; Cervantes, Carla F; Truhlar, Stephanie M E; Cho, Samuel S; Wolynes, Peter G; Komives, Elizabeth A

2007-01-26

IkappaBalpha is the major regulator of transcription factor NF-kappaB function. The ankyrin repeat region of IkappaBalpha mediates specific interactions with NF-kappaB dimers, but ankyrin repeats 1, 5 and 6 display a highly dynamic character when not in complex with NF-kappaB. Using chemical denaturation, we show here that IkappaBalpha displays two folding transitions: a non-cooperative conversion under weak perturbation, and a major cooperative folding phase upon stronger insult. Taking advantage of a native Trp residue in ankyrin repeat (AR) 6 and engineered Trp residues in AR2, AR4 and AR5, we show that the cooperative transition involves AR2 and AR3, while the non-cooperative transition involves AR5 and AR6. The major structural transition can be affected by single amino acid substitutions converging to the "consensus" ankyrin repeat sequence, increasing the native state stability significantly. We further characterized the structural and dynamic properties of the native state ensemble of IkappaBalpha and the stabilized mutants by H/(2)H exchange mass spectrometry and NMR. The solution experiments were complemented with molecular dynamics simulations to elucidate the microscopic origins of the stabilizing effect of the consensus substitutions, which can be traced to the fast conformational dynamics of the folded ensemble.

Influence of excitation frequency on the metastable atoms and electron energy distribution function in a capacitively coupled argon discharge

NASA Astrophysics Data System (ADS)

Sharma, S.; Sirse, N.; Turner, M. M.; Ellingboe, A. R.

2018-06-01

One-dimensional particle-in-cell simulation is used to simulate the capacitively coupled argon plasma for a range of excitation frequency from 13.56 MHz to 100 MHz. The argon chemistry set can, selectively, include two metastable levels enabling multi-step ionization and metastable pooling. The results show that the plasma density decreases when metastable atoms are included with higher discrepancy at a higher excitation frequency. The contribution of multistep ionization to the overall density increases with the excitation frequency. The electron temperature increases with the inclusion of metastable atoms and decreases with the excitation frequency. At a lower excitation frequency, the density of Ar** (3p5 4p, 13.1 eV) is higher than that of Ar* (3p5 4s, 11.6 eV), whereas at higher excitation frequencies, the Ar* (3p5 4s, 11.6 eV) is the dominant metastable atom. The metastable and electron temperature profile evolve from a parabolic profile at a lower excitation frequency to a saddle type profile at a higher excitation frequency. With metastable, the electron energy distribution function (EEDF) changes its shape from Druyvesteyn type, at a low excitation frequency, to bi-Maxwellian, at a high frequency plasma excitation; however, a three-temperature EEDF is observed without metastable atoms.

End-of-Century Projections of North American Atmospheric River Events in CMIP5 Climate Models

NASA Astrophysics Data System (ADS)

Warner, M.; Mass, C.; Salathe, E. P., Jr.

2014-12-01

Most extreme precipitation events that occur along the North American west coast are associated with narrow plumes of above-average water vapor concentration that stretch from the tropics or subtropics to the West Coast. These events generally occur during the wet season (October-March) and are referred to as atmospheric rivers (AR). ARs can cause major river management problems, damage from flooding or landslides, and loss of life. It is expected that anthropogenic global warming could lead to thermodynamic and dynamic changes in the atmosphere, such as increases in water vapor content and, thus, precipitation, and shifts in the climatological jet stream. Since AR events are associated with extreme values of integrated water vapor (IWV) near the West Coast, increases in IWV could impact the intensity of AR events intersecting the coast. Additionally, ARs are associated with cyclonic activity that originates near and propagates along the jet stream. The jet stream configuration influences the frequency and location of AR landfall along the North American west coast. It is probable that any changes in the general circulation of the atmosphere will result in changes in the frequency, orientation, and location of AR landfalls. Global climate models have sufficient resolution to simulate synoptic features associated with AR events, such as high values of vertically integrated vapor transport (IVT) approaching the coast. Ten Coupled Model Intercomparison Project (CMIP5) simulations are used to identify changes in ARs impacting the west coast of North America between historical (1970-1999) and end-of-century (2070-2099) runs, using representative concentration pathway (RCP) 8.5. The most extreme ARs are identified in both time periods by the 99th percentile of IVT days along a north-south transect offshore of the coast. Integrated water vapor (IWV) and IVT are predicted to increase, while lower-tropospheric winds change little. Winter-mean precipitation along the West Coast increases by 11-18% (4-6% C-1) while precipitation on extreme IVT days increases by 15-39% (5-19% C-1). The frequency of IVT days above the historical 99th percentile threshold increases as much as 290% by the end of this century.

CSIR Contribution to Defining Adaptive Capacity in the Context of Environmental Change

DTIC Science & Technology

2015-06-30

of Environmental Change 5a. CONTRACT NUMBER W911NF-14-1-0113 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6 . AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...Change page 4 The metrics were used to identify areas of vulnerability within the Mississippi River basin and Nile River basin region. The IPCC ...The opportunities for improving the communities’ adaptive capacity (in accordance with the IPCC framework) relate to the reduction of the hazard

The use of augmented reality glasses in central line simulation: “see one, simulate many, do one competently, and teach everyone”

PubMed Central

Huang, Cynthia Y; Thomas, Jonathan B; Alismail, Abdullah; Cohen, Avi; Almutairi, Waleed; Daher, Noha S; Terry, Michael H; Tan, Laren D

2018-01-01

Objective The aim of this study was to investigate the feasibility of using augmented reality (AR) glasses in central line simulation by novice operators and compare its efficacy to standard central line simulation/teaching. Design This was a prospective randomized controlled study enrolling 32 novice operators. Subjects were randomized on a 1:1 basis to either simulation using the augmented virtual reality glasses or simulation using conventional instruction. Setting The study was conducted in tertiary-care urban teaching hospital. Subjects A total of 32 adult novice central line operators with no visual or auditory impairments were enrolled. Medical doctors, respiratory therapists, and sleep technicians were recruited from the medical field. Measurements and main results The mean time for AR placement in the AR group was 71±43 s, and the time to internal jugular (IJ) cannulation was 316±112 s. There was no significant difference in median (minimum, maximum) time (seconds) to IJ cannulation for those who were in the AR group and those who were not (339 [130, 550] vs 287 [35, 475], p=0.09), respectively. There was also no significant difference between the two groups in median total procedure time (524 [329, 792] vs 469 [198, 781], p=0.29), respectively. There was a significant difference in the adherence level between the two groups favoring the AR group (p=0.003). Conclusion AR simulation of central venous catheters in manikins is feasible and efficacious in novice operators as an educational tool. Future studies are recommended in this area as it is a promising area of medical education. PMID:29785148

MHD Simulation for Investigating the Dynamic State Transition Responsible for a Solar Eruption in Active Region 12158

NASA Astrophysics Data System (ADS)

Lee, Hwanhee; Magara, Tetsuya

2018-06-01

We present a magnetohydrodynamic model of solar eruption based on the dynamic state transition from the quasi-static state to the eruptive state of an active region (AR) magnetic field. For the quasi-static state before an eruption, we consider the existence of a slow solar wind originating from an AR, which may continuously make the AR magnetic field deviate from mechanical equilibrium. In this model, we perform a three-dimensional magnetohydrodynamic simulation of AR 12158 producing a coronal mass ejection, where the initial magnetic structure of the simulation is given by a nonlinear force-free field derived from an observed photospheric vector magnetic field. We then apply a pressure-driven outflow to the upper part of the magnetic structure to achieve a quasi-static pre-eruptive state. The simulation shows that the eruptive process observed in this AR may be caused by the dynamic state transition of an AR magnetic field, which is essentially different from the destabilization of a static magnetic field. The dynamic state transition is determined from the shape evolution of the magnetic field line according to the κH-mechanism. This work demonstrates how the mechanism works to produce a solar eruption in the dynamic solar corona governed by the gravitational field and the continuous outflows of solar wind.

Projections of wind-waves in South China Sea for the 21st century

NASA Astrophysics Data System (ADS)

Mohammed, Aboobacker; Dykyi, Pavlo; Zheleznyak, Mark; Tkalich, Pavel

2013-04-01

IPCC-coordinated work has been completed within Fourth Assessment Report (AR4) to project climate and ocean variables for the 21st century using coupled atmospheric-ocean General Circulation Models (GCMs). GCMs are not having a wind-wave variable due to a poor grid resolution; therefore, dynamical downscaling of wind-waves to the regional scale is advisable using well established models, such as Wave Watch III (WWIII) and SWAN. Rectilinear-coordinates WWIII model is adapted for the far field comprising the part of Pacific and Indian Oceans centered at the South China Sea and Sunda Shelf (90 °E-130 °E, 10 °S - 26.83 °N) with a resolution of 10' (about 18 km). Near-field unstructured-mesh SWAN model covers Sunda Shelf and centered on Singapore Strait, while reading lateral boundary values from WWIII model. The unstructured grid has the coarsest resolution in the South China Sea (6 to 10 km), medium resolution in the Malacca Strait (1 to 2 km), and the finest resolution in the Singapore Strait (400 m) and along the Singapore coastline (up to 100 m). Following IPCC methodology, the model chain is validated climatologically for the past period 1961-1990 against Voluntary Observing Ship (VOS) data; additionally, the models are validated using recent high-resolution satellite data. The calibrated model chain is used to project waves to 21st century using WRF-downscaled wind speed output of CCSM GCM run for A1FI climate change scenario. To comply with IPCC methodology the entire modeling period is split into three 30-years periods for which statistical parameters are computed individually. Time series of significant wave height at key points near Singapore and on ship sea routes in the SCS are statistically analysed to get probability distribution functions (PDFs) of extreme values. Climatological maps of mean and maximum significant wave height (SWH) values, and mean wave period are built for Singapore region for each 30-yrs period. Linear trends of mean SWH values for northeast (NE) and southwest (SW) monsoons have been derived. The maximum values of predicted 100 year return period (YRP) SWH are obtained for the 1st 30-yrs period (2011-2040). In the deep eastern part of the Singapore, 100yrp SWH are 2.4 - 2.8 m, whereas those at the shallow nearshore areas are 1.7-2.3 m. On the ship routes at Sunda Shelf the 100 YRP SWHs are 1.1 - 3.2 m, and those at the SCS routes are 3.6 - 10.4 m. The biggest changes in future against hindcasted SWH is in first 30-yrs, where extreme 100 YRP SWH will grow up in the range from 36%-120% at points near Singapore and to 39%-108% at ship sea routes.

Final Technical Report for Project "Improving the Simulation of Arctic Clouds in CCSM3"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stephen J. Vavrus

2008-11-15

This project has focused on the simulation of Arctic clouds in CCSM3 and how the modeled cloud amount (and climate) can be improved substantially by altering the parameterized low cloud fraction. The new formula, dubbed 'freeezedry', alleviates the bias of excessive low clouds during polar winter by reducing the cloud amount under very dry conditions. During winter, freezedry decreases the low cloud amount over the coldest regions in high latitudes by over 50% locally and more than 30% averaged across the Arctic (Fig. 1). The cloud reduction causes an Arctic-wide drop of 15 W m{sup -2} in surface cloud radiativemore » forcing (CRF) during winter and about a 50% decrease in mean annual Arctic CRF. Consequently, wintertime surface temperatures fall by up to 4 K on land and 2-8 K over the Arctic Ocean, thus significantly reducing the model's pronounced warm bias (Fig. 1). While improving the polar climate simulation in CCSM3, freezedry has virtually no influence outside of very cold regions (Fig. 2) or during summer (Fig. 3), which are space and time domains that were not targeted. Furthermore, the simplicity of this parameterization allows it to be readily incorporated into other GCMs, many of which also suffer from excessive wintertime polar cloudiness, based on the results from the CMIP3 archive (Vavrus et al., 2008). Freezedry also affects CCSM3's sensitivity to greenhouse forcing. In a transient-CO{sub 2} experiment, the model version with freezedry warms up to 20% less in the North Polar and South Polar regions (1.5 K and 0.5 K smaller warming, respectively) (Fig. 4). Paradoxically, the muted high-latitude response occurs despite a much larger increase in cloud amount with freezedry during non-summer months (when clouds warm the surface), apparently because of the colder modern reference climate. These results of the freezedry parameterization have recently been published (Vavrus and D. Waliser, 2008: An improved parameterization for simulating Arctic cloud amount in the CCSM3 climate model. J. Climate, 21, 5673-5687.). The article also provides a novel synthesis of surface- and satellite-based Arctic cloud observations that show how much the new freezedry parameterization improves the simulated cloud amount in high latitudes (Fig. 3). Freezedry has been incorporated into the CCSM3.5 version, in which it successfully limits the excessive polar clouds, and may be used in CCSM4. Material from this work is also appearing in a synthesis article on future Arctic cloud changes (Vavrus, D. Waliser, J. Francis, and A. Schweiger, 'Simulations of 20th and 21st century Arctic cloud amount in the global climate models assessed in the IPCC AR4', accepted in Climate Dynamics) and was used in a collaborative paper on Arctic cloud-sea ice coupling (Schweiger, A., R. Lindsay, S. Vavrus, and J. Francis, 2008: Relationships between Arctic sea ice and clouds during autumn. J. Climate, 21, 4799-4810.). This research was presented at the 2007 CCSM Annual Workshop, as well as the CCSM's 2007 Atmospheric Model Working Group and Polar Working Group Meetings. The findings were also shown at the 2007 Climate Change Prediction Program's Science Team Meeting. In addition, I served as an instructor at the International Arctic Research Center's (IARC) Summer School on Arctic Climate Modeling in Fairbanks this summer, where I presented on the challenges and techniques used in simulating polar clouds. I also contributed to the development of a new Arctic System Model by attending a workshop in Colorado this summer on this fledgling project. Finally, an outreach activity for the general public has been the development of an interactive web site () that displays Arctic cloud amount in the CMIP3 climate model archive under present and future scenarios. This site allows users to make polar and global maps of a variety of climate variables to investigate the individual and ensemble-mean GCM response to greenhouse warming and the extent to which models adequately represent Arctic clouds in the modern climate. This site was used extensively in the IARC summer school projects. This work has also led to a collaboration this year during a 4-month visit I made to NCAR through its Faculty Fellowship Program. I worked with scientists Marika Holland, David Bailey, Andrew Gettleman, and Jen Kay, who are researching polar climate and/or clouds. I met with this group frequently during my visit, leading to some fruitful interactions. This work led to the discovery of a tightly coupled response of clouds and sea ice during intervals of rapid sea ice loss in greenhouse simulations, as well as advising on the evolving CCSM3.5 to CCSM4 model development. This involvement with NCAR also led to a longer-term connection, as I have recently begun a two-year stint on the SSC for CCSM.« less

The cloud-radiative forcing of the U.S. landfalling atmospheric rivers

NASA Astrophysics Data System (ADS)

Luo, Qianwen

Atmospheric rivers (ARs) are narrow channels in the atmosphere that transport an enormous amount of moisture from the tropics to the higher latitudes. Streaks of highly reflective clouds are observed along with the ARs in satellite imagery. These clouds both influence the moisture transport of ARs, as well as modify the Earth-Atmospheric energy budget through pathways such as cloud-radiative forcing (CRF). This dissertation studies the CRF of the U.S. Landfalling ARs in weather and climate scales. Three crucial questions are addressed. First, how do clouds produced by the ARs modulate the moisture and heat balance of the Earth-Atmospheric system? Even though studies of ARs date back to the 90s, past research has been primarily focused on their hydrological impacts. We addressed this research gap by comparing the dominant types of precipitating clouds and convection of two ARs. Through quantifying their effects on the energy balance in the midlatitudes, we found that when deep convection was the dominant cloud types of an AR, impressive CRF cooling was produced. Second, what are the sufficient climate conditions for the extensive CRF in the continental U.S.? We studied 60 ARs that reached the California coast (the Southwest ARs) and 60 ARs that reached Pacific Northwest during Nov-Mar, 2000-2008. It was found that when these West-Coast ARs were followed by the moisture surge from the Gulf of Mexico (the Gulf-Coast AR), it resulted in apparent statewide CRF. Such condition happened more frequently in the Southwest-AR scenario. Third, how does the subgrid-scale-convection-induced CRF influence the moisture transport of ARs?We ran two WRF ARW simulations for a Southwest-AR that was followed by a Gulf-Coast AR. The only difference between the two simulations was one considered the CRF of subgrid-scale clouds while the other did not. By comparing the two simulations, we found that the subgrid-scale-convection-induced CRF helped prolong the lifespan of clouds in an AR, thus enabling moisture to be transported further downstream. In short, this work helps improve our understanding of CRF of the U.S. landfalling ARs from both weather and climate perspectives. Our results are useful for validating the representation of clouds and radiation processes in weather and climate models, thereby help to improve AR predictions.

Contributions of the Atmospheric Radiation Measurement (ARM) Program and the ARM Climate Research Facility to the U.S. Climate Change Science Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

SA Edgerton; LR Roeder

The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. The 2007 assessment (AR4) by the Intergovernmental Panel on Climate Change (IPCC) reports a substantial range among GCMs in climate sensitivity to greenhousemore » gas emissions. The largest contributor to this range lies in how different models handle changes in the way clouds absorb or reflect radiative energy in a changing climate (Solomon et al. 2007). In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program within the Office of Biological and Environmental Research (BER) to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To address this problem, BER has adopted a unique two-pronged approach: * The ARM Climate Research Facility (ACRF), a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes. * The ARM Science Program, focused on the analysis of ACRF data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report describes accomplishments of the BER ARM Program toward addressing the primary uncertainties related to climate change prediction as identified by the IPCC.« less

The importance of hydrological uncertainty assessment methods in climate change impact studies

NASA Astrophysics Data System (ADS)

Honti, M.; Scheidegger, A.; Stamm, C.

2014-08-01

Climate change impact assessments have become more and more popular in hydrology since the middle 1980s with a recent boost after the publication of the IPCC AR4 report. From hundreds of impact studies a quasi-standard methodology has emerged, to a large extent shaped by the growing public demand for predicting how water resources management or flood protection should change in the coming decades. The "standard" workflow relies on a model cascade from global circulation model (GCM) predictions for selected IPCC scenarios to future catchment hydrology. Uncertainty is present at each level and propagates through the model cascade. There is an emerging consensus between many studies on the relative importance of the different uncertainty sources. The prevailing perception is that GCM uncertainty dominates hydrological impact studies. Our hypothesis was that the relative importance of climatic and hydrologic uncertainty is (among other factors) heavily influenced by the uncertainty assessment method. To test this we carried out a climate change impact assessment and estimated the relative importance of the uncertainty sources. The study was performed on two small catchments in the Swiss Plateau with a lumped conceptual rainfall runoff model. In the climatic part we applied the standard ensemble approach to quantify uncertainty but in hydrology we used formal Bayesian uncertainty assessment with two different likelihood functions. One was a time series error model that was able to deal with the complicated statistical properties of hydrological model residuals. The second was an approximate likelihood function for the flow quantiles. The results showed that the expected climatic impact on flow quantiles was small compared to prediction uncertainty. The choice of uncertainty assessment method actually determined what sources of uncertainty could be identified at all. This demonstrated that one could arrive at rather different conclusions about the causes behind predictive uncertainty for the same hydrological model and calibration data when considering different objective functions for calibration.

Extreme Landfalling Atmospheric River Events in Arizona: Possible Future Changes

NASA Astrophysics Data System (ADS)

Singh, I.; Dominguez, F.

2016-12-01

Changing climate could impact the frequency and intensity of extreme atmospheric river events. This can have important consequences for regions like the Southwestern United Sates that rely upon AR-related precipitation for meeting their water demand and are prone to AR-related flooding. This study investigates the effects of climate change on extreme AR events in the Salt and Verde river basins in Central Arizona using a pseudo global warming method (PGW). First, the five most extreme events that affected the region were selected. High-resolution control simulations of these events using the Weather Research and Forecasting model realistically captured the magnitude and spatial distribution of precipitation. Subsequently, following the PGW approach, the WRF initial and lateral boundary conditions were perturbed. The perturbation signals were obtained from an ensemble of 9 General Circulation Models for two warming scenarios - Representative Concentration Pathway (RCP) 4.5 and RCP8.5. Several simulations were conducted changing the temperature and relative humidity fields. PGW simulations reveal that while the overall dynamics of the storms did not change significantly, there was marked strengthening of associated Integrated Vertical Transport (IVT) plumes. There was a general increase in the precipitation over the basins due to increased moisture availability, but heterogeneous spatial changes. Additionally, no significant changes in the strength of the pre-cold frontal low-level jet in the future simulations were observed.

Linguistic analysis of IPCC summaries for policymakers and associated coverage

NASA Astrophysics Data System (ADS)

Barkemeyer, Ralf; Dessai, Suraje; Monge-Sanz, Beatriz; Renzi, Barbara Gabriella; Napolitano, Giulio

2016-03-01

The Intergovernmental Panel on Climate Change (IPCC) Summary for Policymakers (SPM) is the most widely read section of IPCC reports and the main springboard for the communication of its assessment reports. Previous studies have shown that communicating IPCC findings to a variety of scientific and non-scientific audiences presents significant challenges to both the IPCC and the mass media. Here, we employ widely established sentiment analysis tools and readability metrics to explore the extent to which information published by the IPCC differs from the presentation of respective findings in the popular and scientific media between 1990 and 2014. IPCC SPMs clearly stand out in terms of low readability, which has remained relatively constant despite the IPCC’s efforts to consolidate and readjust its communications policy. In contrast, scientific and quality newspaper coverage has become increasingly readable and emotive. Our findings reveal easy gains that could be achieved in making SPMs more accessible for non-scientific audiences.

New chairman takes helm at Climate Change Panel

NASA Astrophysics Data System (ADS)

Showstack, Randy

An Indian industrial engineer and economist who supports the Kyoto Protocol, and who has sharply criticized the administration of George W. Bush on the climate change issue for not doing enough to curb greenhouse gas emissions, won the first-ever contested election for chairman of the Intergovernmental Panel on Climate Change (IPCC) during a meeting on 19 April.Rajendra Pachauri is the first representative from a developing country to chair the IPCC, a panel of about 2,500 experts on a wide range of areas related to climate change. The IPCC was established in 1988 by the World Meteorological Organization and the United Nations Environment Programme. In total, the IPCC currently includes 192 member states. Although the bulk of the IPCC's work is conducted by three technical working groups, the chairman plays a key role in facilitating the overall process of the IPCC, organizing the scientific debate within the IPCC, and serving as chief spokesman.

Antibiotic Resistome: Improving Detection and Quantification Accuracy for Comparative Metagenomics.

PubMed

Elbehery, Ali H A; Aziz, Ramy K; Siam, Rania

2016-04-01

The unprecedented rise of life-threatening antibiotic resistance (AR), combined with the unparalleled advances in DNA sequencing of genomes and metagenomes, has pushed the need for in silico detection of the resistance potential of clinical and environmental metagenomic samples through the quantification of AR genes (i.e., genes conferring antibiotic resistance). Therefore, determining an optimal methodology to quantitatively and accurately assess AR genes in a given environment is pivotal. Here, we optimized and improved existing AR detection methodologies from metagenomic datasets to properly consider AR-generating mutations in antibiotic target genes. Through comparative metagenomic analysis of previously published AR gene abundance in three publicly available metagenomes, we illustrate how mutation-generated resistance genes are either falsely assigned or neglected, which alters the detection and quantitation of the antibiotic resistome. In addition, we inspected factors influencing the outcome of AR gene quantification using metagenome simulation experiments, and identified that genome size, AR gene length, total number of metagenomics reads and selected sequencing platforms had pronounced effects on the level of detected AR. In conclusion, our proposed improvements in the current methodologies for accurate AR detection and resistome assessment show reliable results when tested on real and simulated metagenomic datasets.

Bridging the Gap Between Policy and Research Infrastructure: Risk and Vulnerability Case Study

NASA Astrophysics Data System (ADS)

Hugo, Wim; Rogers, Annabelle

2017-04-01

Linking sound scientific data and conclusions to decision and policy support is not a trivial task, and the difficulty in achieving this has been highlighted more than a decade ago (Reid, 2004). There are several reasons why this is the case, inter alia: 1. The language, (vocabularies, framework, and heuristics) adopted by the research community in a specific discipline may not translate into meaningful implementation language (Preston et al., 2015); 2. The researchers may not be in a position of influence (which includes aspects such as writing policy briefs, undertaking personal initiatives, and building up public or industry concern and interest) (Fox and Sitkin, 2015); 3. The frequency, timing, and/or certainty associated with research output is at odds with decision and policy-making cycles. Research typically progresses until there is a defensible level of certainty in statistical assessment of a result, while policy decisions are often made within a regular cycle; 4. Scientists are not trained for, or measured by, the typical work required for decision and policy support: synthesis of scenarios and cost-benefits of such scenarios given sometimes significant uncertainty in the input data, and cross-disciplinary concerns that need to be balanced. There is a significant expectation that research output, being increasingly open, standardised, and managed in formal research data infrastructure, will be useful to policy and decision makers without much additional intervention and modification. We believe that this is unlikely to be feasible in the majority of cases. For most instances, it will be necessary to provide a framework for the translation of scientific output into decision and policy support metrics or indicators at a frequency, with spatial and temporal resolution, and thematic coverage that suits the decision to be made. Such frameworks exist, since the need has been identified - sometimes formally - such as the very detailed framework developed by IPCC for translating climate science into policy - (IPCC, 2007), or less formally - such as the move to develop Essential Biodiversity Variables, loosely designed to support Aichi Targets (Pereira et al., 2013) or the UN Sustainable Development Goals (UN, 2016). In the paper, we examine a number of these frameworks, map them onto a generic framework for the translation of research output into policy and decision support, and discuss an example from the South African Risk and Vulnerability Atlas in detail. References Craig R. Fox & Sim B. Sitkin (2015). Bridging the divide between behavioral science & policy, Behavioral Science & Policy, Spring 2015, https://behavioralpolicy.org/wp-content/uploads/2016/1-1/Bridging-the-divide-between-behavioral-science-and-policy.pdf IPCC (2007). Conceptual framework for the identification and assessment of key vulnerabilities, https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch19s19-1-2.html Pereira et al. (2013). Essential Biodiversity Variables, Science 18 Jan 2013: Vol. 339, Issue 6117, pp. 277-278 DOI: 10.1126/science.1229931 Preston, B.L., Mustelin, J. & Maloney, M.C. Mitig Adapt Strateg Glob Change (2015) 20: 467. doi:10.1007/s11027-013-9503-x Reid WV (2004) Bridging the Science-Policy Divide. PLoS Biol 2(2): e27. doi:10.1371/journal.pbio.0020027 UN (2016). Sustainable Development Goals, http://www.un.org/sustainabledevelopment/sustainable-development-goals/

Recently amplified arctic warming has contributed to a continual global warming trend

NASA Astrophysics Data System (ADS)

Huang, Jianbin; Zhang, Xiangdong; Zhang, Qiyi; Lin, Yanluan; Hao, Mingju; Luo, Yong; Zhao, Zongci; Yao, Yao; Chen, Xin; Wang, Lei; Nie, Suping; Yin, Yizhou; Xu, Ying; Zhang, Jiansong

2017-12-01

The existence and magnitude of the recently suggested global warming hiatus, or slowdown, have been strongly debated1-3. Although various physical processes4-8 have been examined to elucidate this phenomenon, the accuracy and completeness of observational data that comprise global average surface air temperature (SAT) datasets is a concern9,10. In particular, these datasets lack either complete geographic coverage or in situ observations over the Arctic, owing to the sparse observational network in this area9. As a consequence, the contribution of Arctic warming to global SAT changes may have been underestimated, leading to an uncertainty in the hiatus debate. Here, we constructed a new Arctic SAT dataset using the most recently updated global SATs2 and a drifting buoys based Arctic SAT dataset11 through employing the `data interpolating empirical orthogonal functions' method12. Our estimate of global SAT rate of increase is around 0.112 °C per decade, instead of 0.05 °C per decade from IPCC AR51, for 1998-2012. Analysis of this dataset shows that the amplified Arctic warming over the past decade has significantly contributed to a continual global warming trend, rather than a hiatus or slowdown.

Intra-operative peritoneal lavage for colorectal cancer

PubMed Central

Passot, Guillaume; Mohkam, Kayvan; Cotte, Eddy; Glehen, Olivier

2014-01-01

Free cancer cells can be detected in peritoneal fluid at the time of colorectal surgery. Peritoneal lavage in colorectal surgery for cancer is not used in routine, and the prognostic significance of intraperitoneal free cancer cells (IPCC) remains unclear. Data concerning the technique of peritoneal lavage to detect IPCC and its timing regarding colorectal resection are scarce. However, positive IPCC might be the first step of peritoneal spread in colorectal cancers, which could lead to early specific treatments. Because of the important heterogeneity of IPCC determination in reported studies, no treatment have been proposed to patients with positive IPCC. Herein, we provide an overview of IPCC detection and its impact on recurrence and survival, and we suggest further multi-institutional studies to evaluate new treatment strategies. PMID:24616569

Aquatic Ecosystem Services in the 21st Century Northeast Corridor: Assessment Using a Regional Earth System Model

NASA Astrophysics Data System (ADS)

Rosenzweig, B.; Miara, A.; Stewart, R. J.; Wollheim, W. M.; Vorosmarty, C. J.

2012-12-01

Aquatic ecosystems of the Northeast United States will be significantly impacted by both global climate change and the regional-scale strategic management decisions made in the next few years. We have developed a Regional Earth System Model for the Northeast Corridor (NE-RESM) that simulates the impacts of climate, land use, and development policy on the interacting cycles of energy, water, carbon and nutrients. The NE-RESM will provide a unique and critically needed tool for policymakers to understand how their current decisions will impact ecosystem services over the 21st Century. To test our modeling framework, we conducted a retrospective experiment focusing on the water-energy-economy nexus during the period 2000-2010. Component models were developed to 'translate' physical outputs from the NE-RESM - such as stream discharge and water temperature - into ecosystem services including water regulation for thermoelectric cooling and the ability for streams to serve as a refugia for wildlife. Simulations were performed both with and without Clean Water Act limits on thermal pollution. Through this work, we were able to obtain spatially distributed information on how these laws impact power generation by the thermoelectric sector but also enable Northeast streams to serve as habitat for temperature-sensitive aquatic species (Brook Trout, Atlantic Salmon, River Herring and the American Eel). Our ongoing research examines future climate and policy scenarios through 2100. We are considering the impact of changing land cover patterns (a return to agriculture vs. suburban sprawl) and various strategies to meet energy and municipal water needs under different Representative Concentration Pathways (RCPs) developed for the Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5).

Arctic Ocean Pathways in the 21st century

NASA Astrophysics Data System (ADS)

Aksenov, Yevgeny; van Gennip, Simon J.; Kelly, Stephen J.; Popova, Ekaterina E.; Yool, Andrew

2017-04-01

In the last three decades, changes in the Arctic environment have been occurring at an increasing rate. The opening up of large areas of previously sea ice-covered ocean affects the marine environment with potential impacts on Arctic ecosystems, including through changes in Arctic access, industries and societies. Changes to sea ice and surface winds result in large-scale shifts in ocean circulation and oceanic pathways. This study presents a high-resolution analysis of the projected ocean circulation and pathways of the Arctic water masses across the 21st century. The analysis is based on an eddy-permitting high-resolution global simulation of the ocean general circulation model NEMO (Nucleus for European Modelling of the Ocean) at the 1/4-degree horizontal resolution. The atmospheric forcing is from HadGEM2-ES model output from IPCC Assessment Report 5 (AR5) simulations performed for Coupled Model Intercomparison Project 5 (CMIP5), and follow the Representative Concentration Pathway 8.5 (RCP8.5) scenario. During the 21st century the AO experiences a significant warming, with sea surface temperature increased by in excess of 4 deg. C. Annual mean Arctic sea ice thickness drops to less than 0.5m, and the Arctic Ocean is ice-free in summer from the mid-century. We use an off-line tracer technique to investigate Arctic pathways of the Atlantic and Pacific waters (AW and PW respectively) under this future climate. The AW tracers have been released in the eastern Fram Strait and in the western Barents Sea, whereas the PW tracer has been seeded in the Bering Strait. In the second half of the century the upper 1000 m ocean circulation shows a reduction in the eastward AW flow along the continental slopes towards the Makarov and Canada basins and a deviation of the PW flow away from the Beaufort Sea towards the Siberian coast. Strengthening of Arctic boundary current and intensification of the cyclonic gyre in the Nansen basin of the Arctic Ocean is accompanied by weakening of the current and an anti-cyclonic gyre spin-up in the Makarov Basin. This presents a shift of the Arctic circulation "dipole" and of the Transpolar Drift, with the consequence that the PW flow towards Fram Strait is significantly reduced by the end of the century, weakening the Pacific-Atlantic connection via the Arctic Ocean, and reducing the Arctic freshwater outflow into the North Atlantic. Examination of the simulations suggests that these circulation changes are primarily due to the shift in the wind.

Simulating Soil Organic Carbon Stock Changes in Agro-ecosystems using CQESTR, DayCent, and IPCC Tier 1 Methods

USDA-ARS?s Scientific Manuscript database

Models are often used to quantify how land use change and management impact soil organic carbon (SOC) stocks because it is often not feasible to use direct measuring methods. Because models are simplifications of reality, it is essential to compare model outputs with measured values to evaluate mode...

Modelling the thermosteric contribution to global and regional sea-level rise during the last interglacial

NASA Astrophysics Data System (ADS)

Singarayer, Joy; Stone, Emma; Whipple, Matthew; Lunt, Dan; Bouttes, Nathaelle; Gregory, Jonathan

2014-05-01

Global sea level during the last interglacial is likely to have been between 5.5 and 9m above present (Dutton and Lambeck, 2012). Recent calculations, taking into account latest NEEM ice core information, suggest that Greenland would probably not have contributed more than 2.2m to this (Stone et al, 2013), implying a considerable contribution from Antarctica. Previous studies have suggested a significant loss from the West Antarctic ice-sheet (e.g. Holden et al, 2010), which could be initiated following a collapse of the Atlantic Meridional Overturning Circulation (AMOC) and resultant warming in the Southern Ocean. Here, model simulations with FAMOUS and HadCM3 have been performed of the last interglacial under various scenarios of reduced Greenland and Antarctic ice-sheet configurations, and with and without collapsed AMOC. Thermal expansion and changes in regional density structure (resulting from ocean circulation changes) can also influence sea level, in addition to ice mass effects discussed thus far. The HadCM3 and FAMOUS simulations will be used to estimate the contribution to global and regional sea level change in interglacials from the latter two factors using a similar methodology to the IPCC TAR/AR4 estimations of future sea level rise (Gregory and Lowe, 2000). The HadCM3 and FAMOUS both have a rigid lid in their ocean model, and consequently a fixed ocean volume. Thermal expansion can, however, be calculated as a volume change from in-situ density (a prognostic variable from the model). Relative sea surface topography will then be estimated from surface pressure gradients and changes in atmospheric pressure. Dutton A., and Lambeck K., 2013. Ice Volume and Sea Level During the Last Interglacial. Science, 337, 216-219 Gregory J.M. and Lowe J.A., 2000. Predictions of global and regional sea-level using AOGCMs with and without flux adjustment. GRL, 27, 3069-3072 Holden P. et al., 2010. Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials. Clim. Past, 6, 431-443 Stone E.J., et al., 2013. Quantification of the Greenland ice sheet contribution to Last Interglacial sea level rise. Clim. Past, 9, 621-639

Creating Dynamically Downscaled Seasonal Climate Forecast and Climate Change Projection Information for the North American Monsoon Region Suitable for Decision Making Purposes

NASA Astrophysics Data System (ADS)

Castro, C. L.; Dominguez, F.; Chang, H.

2010-12-01

Current seasonal climate forecasts and climate change projections of the North American monsoon are based on the use of course-scale information from a general circulation model. The global models, however, have substantial difficulty in resolving the regional scale forcing mechanisms of precipitation. This is especially true during the period of the North American Monsoon in the warm season. Precipitation is driven primarily due to the diurnal cycle of convection, and this process cannot be resolve in coarse-resolution global models that have a relatively poor representation of terrain. Though statistical downscaling may offer a relatively expedient method to generate information more appropriate for the regional scale, and is already being used in the resource decision making processes in the Southwest U.S., its main drawback is that it cannot account for a non-stationary climate. Here we demonstrate the use of a regional climate model, specifically the Weather Research and Forecast (WRF) model, for dynamical downscaling of the North American Monsoon. To drive the WRF simulations, we use retrospective reforecasts from the Climate Forecast System (CFS) model, the operational model used at the U.S. National Center for Environmental Prediction, and three select “well performing” IPCC AR 4 models for the A2 emission scenario. Though relatively computationally expensive, the use of WRF as a regional climate model in this way adds substantial value in the representation of the North American Monsoon. In both cases, the regional climate model captures a fairly realistic and reasonable monsoon, where none exists in the driving global model, and captures the dominant modes of precipitation anomalies associated with ENSO and the Pacific Decadal Oscillation (PDO). Long-term precipitation variability and trends in these simulations is considered via the standardized precipitation index (SPI), a commonly used metric to characterize long-term drought. Dynamically downscaled climate projection data will be integrated into future water resource projections in the state of Arizona, through a cooperative effort involving numerous water resource stakeholders.

Estimating Amazonian rainforest stability and the likelihood for large-scale forest dieback

NASA Astrophysics Data System (ADS)

Rammig, Anja; Thonicke, Kirsten; Jupp, Tim; Ostberg, Sebastian; Heinke, Jens; Lucht, Wolfgang; Cramer, Wolfgang; Cox, Peter

2010-05-01

Annually, tropical forests process approximately 18 Pg of carbon through respiration and photosynthesis - more than twice the rate of anthropogenic fossil fuel emissions. Current climate change may be transforming this carbon sink into a carbon source by changing forest structure and dynamics. Increasing temperatures and potentially decreasing precipitation and thus prolonged drought stress may lead to increasing physiological stress and reduced productivity for trees. Resulting decreases in evapotranspiration and therefore convective precipitation could further accelerate drought conditions and destabilize the tropical ecosystem as a whole and lead to an 'Amazon forest dieback'. The projected direction and intensity of climate change vary widely within the region and between different scenarios from climate models (GCMs). In the scope of a World Bank-funded study, we assessed the 24 General Circulation Models (GCMs) evaluated in the 4th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4) with respect to their capability to reproduce present-day climate in the Amazon basin using a Bayesian approach. With this approach, greater weight is assigned to the models that simulate well the annual cycle of rainfall. We then use the resulting weightings to create probability density functions (PDFs) for future forest biomass changes as simulated by the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJmL) to estimate the risk of potential Amazon rainforest dieback. Our results show contrasting changes in forest biomass throughout five regions of northern South America: If photosynthetic capacity and water use efficiency is enhanced by CO2, biomass increases across all five regions. However, if CO2-fertilisation is assumed to be absent or less important, then substantial dieback occurs in some scenarios and thus, the risk of forest dieback is considerably higher. Particularly affected are regions in the central Amazon basin. The range of potential biomass change arising from the weighting of rainfall patterns is smaller than the uncertainty arising from CO2-fertilisation effects, which highlights the importance of reducing the uncertainties in the direct effects of CO2 on tropical ecosystems. Strong biomass changes also imply changes in forest structure and thus, forest stability. Our results display shifts in forest composition from closed rainforest to more open forest or even shrubland. Our probability-based risk analysis could be used to advise regional forest protection.

Climate Change in New York State Updating the 2011 ClimAID Climate Risk Information Supplement to NYSERDA Report 11-18 (Responding to Climate Change in New York State)

NASA Technical Reports Server (NTRS)

Horton, Radley M.; Bader, Daniel A.; Rosenzweig, Cynthia; DeGaetano, Arthur T.; Solecki, William

2014-01-01

In its 2013-2014 Fifth Assessment Report (AR5), the Intergovernmental Panel on Climate Change (IPCC) states that there is a greater than 95 percent chance that rising global average temperatures, observed since the mid-20th century, are primarily due to human activities. As had been predicted in the 1800s, the principal driver of climate change over the past century has been increasing levels of atmospheric greenhouse gases associated with fossil-fuel combustion, changing land-use practices, and other human activities. Atmospheric concentrations of the greenhouse gas carbon dioxide are now approximately 40 percent higher than in preindustrial times. Concentrations of other important greenhouse gases, including methane and nitrous oxide, have increased rapidly as well.

Gate simulation of Compton Ar-Xe gamma-camera for radionuclide imaging in nuclear medicine

NASA Astrophysics Data System (ADS)

Dubov, L. Yu; Belyaev, V. N.; Berdnikova, A. K.; Bolozdynia, A. I.; Akmalova, Yu A.; Shtotsky, Yu V.

2017-01-01

Computer simulations of cylindrical Compton Ar-Xe gamma camera are described in the current report. Detection efficiency of cylindrical Ar-Xe Compton camera with internal diameter of 40 cm is estimated as1-3%that is 10-100 times higher than collimated Anger’s camera. It is shown that cylindrical Compton camera can image Tc-99m radiotracer distribution with uniform spatial resolution of 20 mm through the whole field of view.

Assessment of the aerosol distribution over Indian subcontinent in CMIP5 models

NASA Astrophysics Data System (ADS)

Sanap, S. D.; Ayantika, D. C.; Pandithurai, G.; Niranjan, K.

2014-04-01

This paper examines the aerosol distribution over Indian subcontinent as represented in 21 models from Coupled Model Inter-comparison Project Phase 5 (CMIP5) simulations, wherein model simulated aerosol optical depth (AOD) is compared with Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite observations. The objective of the study is to provide an assessment of the capability of various global models, participating in CMIP5 project, in capturing the realistic spatial and temporal distribution of aerosol species over the Indian subcontinent. Results from our analysis show that majority of the CMIP5 models (excepting HADGEM2-ES, HADGEM2-CC) seriously underestimates the spatio-temporal variability of aerosol species over the Indian subcontinent, in particular over Indo-Gangetic Plains (IGP). Since IGP region is dominated by anthropogenic activities, high population density, and wind driven transport of dust and other aerosol species, MODIS observations reveal high AOD values over this region. Though the representation of black carbon (BC) loading in many models is fairly good, the dust loading is observed to be significantly low in majority of the models. The presence of pronounced dust activity over northern India and dust being one of the major constituent of aerosol species, the biases in dust loading has a great impact on the AOD of that region. We found that considerable biases in simulating the 850 hPa wind field (which plays important role in transport of dust from adjacent deserts) would be the possible reason for poor representation of dust AOD and in turn total AOD over Indian region in CMIP5 models. In addition, aerosol radiative forcing (ARF) underestimated/overestimated in most of the models. However, spatial distribution of ARF in multi-model ensemble mean is comparable reasonably well with observations with bias in magnitudes. This analysis emphasizes the fundamental need to improve the representation of aerosol species in current state of the art climate models. As reported in Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4), the level of scientific understanding (LOSU) of climatic impact of aerosols is medium-low. For better understanding of short and long term implications of changing concentrations of aerosol species on climate, it is imperative to have a realistic representation of aerosol distribution over regions with high aerosol loading.

Numerical simulations of water flow and tracer transport in soils at the USDA-ARS Beltsville OPE3 field site

USDA-ARS?s Scientific Manuscript database

The objective of this study was to develop a realistic model to simulate the complex processes of flow and tracer transport in USDA-ARS OPE3 field site and to compare simulation results with the detailed monitoring observations. The site has been studied for over 10 years with the extensive availabl...

Application of nuclear pumped laser to an optical self-powered neutron detector

NASA Astrophysics Data System (ADS)

Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

1996-05-01

A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

A unified equation of state for fluids of C-H-O-N-S-Ar composition and their mixtures up to very high temperatures and pressures

NASA Astrophysics Data System (ADS)

Belonoshko, A. B.; Saxena, S. K.

1992-10-01

A unified equation of state (EOS) is derived for 13 gases (including H2O, CO2, CH4, CO, O2, H2, Ar, N2, NH3, H2S, SO2, COS, and S2) in C-H-O-N-S-Ar system, on the basis of molecular dynamical simulated PVT data, assuming these species to be alpha-exponential-6 fluids at high temperature and pressure. The EOS equation is parameterized for these gases in the ranges of temperature and pressure 400-4000 K and 5-1000 kbar, respectively. It is shown that the equation reproduces most of the available experimental data in the limits of experimental accuracy of volume measurements.

Cucurbit[6]uril: A Possible Host for Noble Gas Atoms.

PubMed

Pan, Sudip; Mandal, Subhajit; Chattaraj, Pratim K

2015-08-27

Density functional and ab initio molecular dynamics studies are carried out to investigate the stability of noble gas encapsulated cucurbit[6]uril (CB[6]) systems. Interaction energy, dissociation energy and dissociation enthalpy are calculated to understand the efficacy of CB[6] in encapsulating noble gas atoms. CB[6] could encapsulate up to three Ne atoms having dissociation energy (zero-point energy corrected) in the range of 3.4-4.1 kcal/mol, whereas due to larger size, only one Ar or Kr atom encapsulated analogues would be viable. The dissociation energy value for the second Ar atom is only 1.0 kcal/mol. On the other hand, the same for the second Kr is -0.5 kcal/mol, implying the instability of the system. The noble gas dissociation processes are endothermic in nature, which increases gradually along Ne to Kr. Kr encapsulated analogue is found to be viable at room temperature. However, low temperature is needed for Ne and Ar encapsulated analogues. The temperature-pressure phase diagram highlights the region in which association and dissociation processes of Kr@CB[6] would be favorable. At ambient temperature and pressure, CB[6] may be used as an effective noble gas carrier. Wiberg bond indices, noncovalent interaction indices, electron density, and energy decomposition analyses are used to explore the nature of interaction between noble gas atoms and CB[6]. Dispersion interaction is found to be the most important term in the attraction energy. Ne and Ar atoms in one Ng entrapped analogue are found to stay inside the cavity of CB[6] throughout the simulation at 298 K. However, during simulation Ng2 units in Ng2@CB[6] flip toward the open faces of CB[6]. After 1 ps, one Ne atom of Ne3@CB[6] almost reaches the open face keeping other two Ne atoms inside. At lower temperature (77 K), all the Ng atoms in Ngn@CB[6] remain well inside the cavity of CB[6] throughout the simulation time (1 ps).

Molecular Dynamics Simulations of an Idealized Shock Tube: N2 in Ar Bath Driven by He

NASA Astrophysics Data System (ADS)

Piskulich, Ezekiel Ashe; Sewell, Thomas D.; Thompson, Donald L.

2015-06-01

The dynamics of 10% N2 in Ar initially at 298 K in an idealized shock tube driven by He was studied using molecular dynamics. The simulations were performed using the Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. Nitrogen was modeled as a Morse oscillator and non-covalent interactions were approximated by the Buckingham exponential-6 pair potential. The initial pressures in the He driver gas and the driven N2/Ar gas were 1000 atm and 20 atm, respectively. Microcanonical trajectories were followed for 2 ns following release of the driver gas. Results for excitation and subsequent relaxation of the N2, as well as properties of the gas during the simulations, will be reported.

Aerosol Indirect Effects on Cirrus Clouds in Global Aerosol-Climate Models

NASA Astrophysics Data System (ADS)

Liu, X.; Zhang, K.; Wang, Y.; Neubauer, D.; Lohmann, U.; Ferrachat, S.; Zhou, C.; Penner, J.; Barahona, D.; Shi, X.

2015-12-01

Cirrus clouds play an important role in regulating the Earth's radiative budget and water vapor distribution in the upper troposphere. Aerosols can act as solution droplets or ice nuclei that promote ice nucleation in cirrus clouds. Anthropogenic emissions from fossil fuel and biomass burning activities have substantially perturbed and enhanced concentrations of aerosol particles in the atmosphere. Global aerosol-climate models (GCMs) have now been used to quantify the radiative forcing and effects of aerosols on cirrus clouds (IPCC AR5). However, the estimate uncertainty is very large due to the different representation of ice cloud formation and evolution processes in GCMs. In addition, large discrepancies have been found between model simulations in terms of the spatial distribution of ice-nucleating aerosols, relative humidity, and temperature fluctuations, which contribute to different estimates of the aerosol indirect effect through cirrus clouds. In this presentation, four GCMs with the start-of-the art representations of cloud microphysics and aerosol-cloud interactions are used to estimate the aerosol indirect effects on cirrus clouds and to identify the causes of the discrepancies. The estimated global and annual mean anthropogenic aerosol indirect effect through cirrus clouds ranges from 0.1 W m-2 to 0.3 W m-2 in terms of the top-of-the-atmosphere (TOA) net radiation flux, and 0.5-0.6 W m-2 for the TOA longwave flux. Despite the good agreement on global mean, large discrepancies are found at the regional scale. The physics behind the aerosol indirect effect is dramatically different. Our analysis suggests that burden of ice-nucleating aerosols in the upper troposphere, ice nucleation frequency, and relative role of ice formation processes (i.e., homogeneous versus heterogeneous nucleation) play key roles in determining the characteristics of the simulated aerosol indirect effects. In addition to the indirect effect estimate, we also use field campaign measurements and satellite retrievals to evaluate the simulated micro- and macro- physical properties of ice clouds in the four GCMs.

The effect of future outdoor air pollution on human health and the contribution of climate change

NASA Astrophysics Data System (ADS)

Silva, R.; West, J. J.; Lamarque, J.; Shindell, D.; Collins, W.; Dalsoren, S. B.; Faluvegi, G. S.; Folberth, G.; Horowitz, L. W.; Nagashima, T.; Naik, V.; Rumbold, S.; Skeie, R.; Sudo, K.; Takemura, T.; Bergmann, D. J.; Cameron-Smith, P. J.; Cionni, I.; Doherty, R. M.; Eyring, V.; Josse, B.; MacKenzie, I. A.; Plummer, D.; Righi, M.; Stevenson, D. S.; Strode, S. A.; Szopa, S.; Zeng, G.

2013-12-01

At present, exposure to outdoor air pollution from ozone and fine particulate matter (PM2.5) causes over 2 million deaths per year, due to respiratory and cardiovascular diseases and lung cancer. Future ambient concentrations of ozone and PM2.5 will be affected by both air pollutant emissions and climate change. Here we estimate the potential impact of future outdoor air pollution on premature human mortality, and isolate the contribution of future climate change due to its effect on air quality. We use modeled present-day (2000) and future global ozone and PM2.5 concentrations from simulations with an ensemble of chemistry-climate models from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). Future air pollution was modeled for global greenhouse gas and air pollutant emissions in the four IPCC AR5 Representative Concentration Pathway (RCP) scenarios, for 2030, 2050 and 2100. All model outputs are regridded to a common 0.5°x0.5° horizontal resolution. Future premature mortality is estimated for each RCP scenario and year based on changes in concentrations of ozone and PM2.5 relative to 2000. Using a health impact function, changes in concentrations for each RCP scenario are combined with future population and cause-specific baseline mortality rates as projected by a single independent scenario in which the global incidence of cardiopulmonary diseases is expected to increase. The effect of climate change is isolated by considering the difference between air pollutant concentrations from simulations with 2000 emissions and a future year climate and simulations with 2000 emissions and climate. Uncertainties in the results reflect the uncertainty in the concentration-response function and that associated with variability among models. Few previous studies have quantified the effects of future climate change on global human health via changes in air quality, and this is the first such study to use an ensemble of global models.

Accounting for wetlands loss in a changing climate in the estimation of long-term flood risks of Devils Lake, North Dakota

NASA Astrophysics Data System (ADS)

Gulbin, S.; Kirilenko, A.; Zhang, X.

2016-12-01

Endorheic (terminal) lakes with no water outlets are sensitive indicators of changes in climate and land cover in the watershed. Regional variation in precipitation pattern in the US Northern Great Plaines lead to a long term flooding of Devils Lake (DL), ND, leading to a 10-m water level rise in just two decades, with estimated flood mitigation costs of over $1 billion. While the climate change contribution to flooding has been established, the role of large scale land conversion to agriculture has not been researched. Wetlands play a very important part in hydrological balance by storing, absorbing and slowing peak water discharge. In ND, 49 % of wetlands are drained and converted to agriculture. We investigated the role of wetlands loss in DL flooding in current and future climate. The Soil and Water Assessment Tool (SWAT) was used to simulate streamflow in all DL watershed subbasins. The model was calibrated using the 1991-2000 USGS gauge data for the first 10 years of study period and validated for the second 10 years (2001-2010), resulting in a satisfactory model performance compared against the measured water discharge in five streams in the watershed and against observed DL water level. A set of wetland loss scenarios were created based on the historical data and the Compound Topographic Index. To emulate the historical and future climate conditions, an ensemble of CMIP5 weather integrations based on IPCC AR5 RCP scenarios was downscaled with the MarkSim weather simulator. Model simulations indicate that the land use change in the DL watershed increased the impacts of climate change on hydrology by further elevating DL water level. Conversely, wetland restoration reduce the flooding and moderates risks of a potential high-impact DL overspill to the Sheyenne River watershed. Further research will concentrate on differentiation of climate change impacts under different types of land use change scenarios.

Regional Climate Change Hotspots over Africa

NASA Astrophysics Data System (ADS)

Anber, U.

2009-04-01

Regional Climate Change Index (RCCI), is developed based on regional mean precipitation change, mean surface air temperature change, and change in precipitation and temperature interannual variability. The RCCI is a comparative index designed to identify the most responsive regions to climate change, or Hot- Spots. The RCCI is calculated for Seven land regions over North Africa and Arabian region from the latest set of climate change projections by 14 global climates for the A1B, A2 and B1 IPCC emission scenarios. The concept of climate change can be approaches from the viewpoint of vulnerability or from that of climate response. In the former case a Hot-Spot can be defined as a region for which potential climate change impacts on the environment or different activity sectors can be particularly pronounced. In the other case, a Hot-Spot can be defined as a region whose climate is especially responsive to global change. In particular, the characterization of climate change response-based Hot-Spot can provide key information to identify and investigate climate change Hot-Spots based on results from multi-model ensemble of climate change simulations performed by modeling groups from around the world as contributions to the Assessment Report of Intergovernmental Panel on Climate Change (IPCC). A Regional Climate Change Index (RCCI) is defined based on four variables: change in regional mean surface air temperature relative to the global average temperature change ( or Regional Warming Amplification Factor, RWAF ), change in mean regional precipitation ( , of present day value ), change in regional surface air temperature interannual variability ( ,of present day value), change in regional precipitation interannual variability ( , of present day value ). In the definition of the RCCI it is important to include quantities other than mean change because often mean changes are not the only important factors for specific impacts. We thus also include inter annual variability, which is critical for many activity sectors, such as agriculture and water management. The RCCI is calculated for the above mentioned set of global climate change simulations and is inter compared across regions to identify climate change, Hot- Spots, that is regions with the largest values of RCCI. It is important to stress that, as will be seen, the RCCI is a comparative index, that is a small RCCI value does not imply a small absolute change, but only a small climate response compared to other regions. The models used are: CCMA-3-T47 CNRM-CM3 CSIRO-MK3 GFDL-CM2-0 GISS-ER INMCM3 IPSL-CM4 MIROC3-2M MIUB-ECHO-G MPI-ECHAM5 MRI-CGCM2 NCAR-CCSM3 NCAR-PCM1 UKMO-HADCM3 Note that the 3 IPCC emission scenarios, A1B, B1 and A2 almost encompass the entire IPCC scenario range, the A2 being close to the high end of the range, the B1 close to the low end and the A1B lying toward the middle of the range. The model data are obtained from the IPCC site and are interpolated onto a common 1 degree grid to facilitate intercomparison. The RCCI is here defined as in Giorgi (2006), except that the entire yea is devided into two six months periods, D J F M A M and J J A S O N. RCCI=[n(∆P)＋n(∆σP)+n(RWAF)+n(∆σT)]D...M + [n(∆P)＋n(∆σP)+n(RWAF)+n(∆σT)]J…N (1)

A correction in the CDM methodological tool for estimating methane emissions from solid waste disposal sites.

PubMed

Santos, M M O; van Elk, A G P; Romanel, C

2015-12-01

Solid waste disposal sites (SWDS) - especially landfills - are a significant source of methane, a greenhouse gas. Although having the potential to be captured and used as a fuel, most of the methane formed in SWDS is emitted to the atmosphere, mainly in developing countries. Methane emissions have to be estimated in national inventories. To help this task the Intergovernmental Panel on Climate Change (IPCC) has published three sets of guidelines. In addition, the Kyoto Protocol established the Clean Development Mechanism (CDM) to assist the developed countries to offset their own greenhouse gas emissions by assisting other countries to achieve sustainable development while reducing emissions. Based on methodologies provided by the IPCC regarding SWDS, the CDM Executive Board has issued a tool to be used by project developers for estimating baseline methane emissions in their project activities - on burning biogas from landfills or on preventing biomass to be landfilled and so avoiding methane emissions. Some inconsistencies in the first two IPCC guidelines have already been pointed out in an Annex of IPCC latest edition, although with hidden details. The CDM tool uses a model for methane estimation that takes on board parameters, factors and assumptions provided in the latest IPCC guidelines, while using in its core equation the one of the second IPCC edition with its shortcoming as well as allowing a misunderstanding of the time variable. Consequences of wrong ex-ante estimation of baseline emissions regarding CDM project activities can be of economical or environmental type. Example of the first type is the overestimation of 18% in an actual project on biogas from landfill in Brazil that harms its developers; of the second type, the overestimation of 35% in a project preventing municipal solid waste from being landfilled in China, which harms the environment, not for the project per se but for the undue generated carbon credits. In a simulated landfill - the same amount of waste for 20 years -, the error would be an overestimation of 25% if the CDM project activity starts from the very first year or an underestimation of 15% if it starts just after the landfill closure. Therefore, a correction in the tool to calculate emissions from landfills as adopted by the CDM Executive Board is needed. Moreover, in countries not using the latest IPCC guidelines, which provides clear formulas to prevent misunderstandings, inventory compilers can also benefit from this paper by having more accurate results in national GHG inventories related to solid waste disposal, especially when increasing amounts of waste are landfilled, which is the case of the developing countries. Copyright © 2015 Elsevier Ltd. All rights reserved.

EDITORIAL: Tropical deforestation and greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Gibbs, Holly K.; Herold, Martin

2007-10-01

Carbon emissions from tropical deforestation have long been recognized as a key component of the global carbon budget, and more recently of our global climate system. Tropical forest clearing accounts for roughly 20% of anthropogenic carbon emissions and destroys globally significant carbon sinks (IPCC 2007). Global climate policy initiatives are now being proposed to address these emissions and to more actively include developing countries in greenhouse gas mitigation (e.g. Santilli et al 2005, Gullison et al 2007). In 2005, at the Conference of the Parties (COP) in Montreal, the United Nations Framework Convention on Climate Change (UNFCCC) launched a new initiative to assess the scientific and technical methods and issues for developing policy approaches and incentives to reduce emissions from deforestation and degradation (REDD) in developing countries (Gullison et al 2007). Over the last two years the methods and tools needed to estimate reductions in greenhouse gas emissions from deforestation have quickly evolved, as the scientific community responded to the UNFCCC policy needs. This focus issue highlights those advancements, covering some of the most important technical issues for measuring and monitoring emissions from deforestation and forest degradation and emphasizing immediately available methods and data, as well as future challenges. Elements for effective long-term implementation of a REDD mechanism related to both environmental and political concerns are discussed in Mollicone et al. Herold and Johns synthesize viewpoints of national parties to the UNFCCC on REDD and expand upon key issues for linking policy requirements and forest monitoring capabilities. In response to these expressed policy needs, they discuss a remote-sensing-based observation framework to start REDD implementation activities and build historical deforestation databases on the national level. Achard et al offer an assessment of remote sensing measurements across the world's tropical forests that can provide key consistency and prioritization for national-level efforts. Gibbs et al calculate a range of national-level forest carbon stock estimates that can be used immediately, and also review ground-based and remote sensing approaches to estimate national-level tropical carbon stocks with increased accuracy. These papers help illustrate that methodologies and tools are indeed available to estimate emissions from deforestation. Clearly, important technical challenges remain (e.g. quantifying degradation, assessing uncertainty, verification procedures, capacity building, and Landsat data continuity) but we now have a sufficient technical base to support REDD early actions and readiness mechanisms for building national monitoring systems. Thus, we enter the COP 13 in Bali, Indonesia with great hope for a more inclusive climate policy encompassing all countries and emissions sources from both land-use and energy sectors. Our understanding of tropical deforestation and carbon emissions is improving and with that, opportunities to conserve tropical forests and the host of ecosystem services they provide while also increasing revenue streams in developing countries through economic incentives to avoid deforestation and degradation. References Gullison R E et al 2007 Tropical forests and climate policy Science 316 985 6 Intergovernmental Panel on Climate Change (IPCC) 2007 Climate Change 2007: The Physical Science Basis: Summary for Policymakers http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf Santilli M et al 2005 Tropical deforestation and the Kyoto Protocol: an editorial essay Clim. Change 71 267 76 Focus on Tropical Deforestation and Greenhouse Gas Emissions Contents The articles below represent the first accepted contributions and further additions will appear in the near future. Pan-tropical monitoring of deforestation F Achard, R DeFries, H Eva, M Hansen, P Mayaux and H-J Stibig Monitoring and estimating tropical forest carbon stocks: making REDD a reality Holly K Gibbs, Sandra Brown, John O Niles and Jonathan A Foley Elements for the expected mechanisms on 'reduced emissions from deforestation and degradation, REDD' under UNFCCC D Mollicone, A Freibauer, E D Schulze, S Braatz, G Grassi and S Federici

Promoting long-term survival of insulin-producing cell grafts that differentiate from adipose tissue-derived stem cells to cure type 1 diabetes.

PubMed

Zhang, Shuzi; Dai, Hehua; Wan, Ni; Moore, Yolonda; Dai, Zhenhua

2011-01-01

Insulin-producing cell clusters (IPCCs) have recently been generated in vitro from adipose tissue-derived stem cells (ASCs) to circumvent islet shortage. However, it is unknown how long they can survive upon transplantation, whether they are eventually rejected by recipients, and how their long-term survival can be induced to permanently cure type 1 diabetes. IPCC graft survival is critical for their clinical application and this issue must be systematically addressed prior to their in-depth clinical trials. Here we found that IPCC grafts that differentiated from murine ASCs in vitro, unlike their freshly isolated islet counterparts, did not survive long-term in syngeneic mice, suggesting that ASC-derived IPCCs have intrinsic survival disadvantage over freshly isolated islets. Indeed, β cells retrieved from IPCC syngrafts underwent faster apoptosis than their islet counterparts. However, blocking both Fas and TNF receptor death pathways inhibited their apoptosis and restored their long-term survival in syngeneic recipients. Furthermore, blocking CD40-CD154 costimulation and Fas/TNF signaling induced long-term IPCC allograft survival in overwhelming majority of recipients. Importantly, Fas-deficient IPCC allografts exhibited certain immune privilege and enjoyed long-term survival in diabetic NOD mice in the presence of CD28/CD40 joint blockade while their islet counterparts failed to do so. Long-term survival of ASC-derived IPCC syngeneic grafts requires blocking Fas and TNF death pathways, whereas blocking both death pathways and CD28/CD40 costimulation is needed for long-term IPCC allograft survival in diabetic NOD mice. Our studies have important clinical implications for treating type 1 diabetes via ASC-derived IPCC transplantation. © 2011 Zhang et al.

Promoting Long-Term Survival of Insulin-Producing Cell Grafts That Differentiate from Adipose Tissue-Derived Stem Cells to Cure Type 1 Diabetes

PubMed Central

Zhang, Shuzi; Dai, Hehua; Wan, Ni; Moore, Yolonda; Dai, Zhenhua

2011-01-01

Background Insulin-producing cell clusters (IPCCs) have recently been generated in vitro from adipose tissue-derived stem cells (ASCs) to circumvent islet shortage. However, it is unknown how long they can survive upon transplantation, whether they are eventually rejected by recipients, and how their long-term survival can be induced to permanently cure type 1 diabetes. IPCC graft survival is critical for their clinical application and this issue must be systematically addressed prior to their in-depth clinical trials. Methodology/Principal Findings Here we found that IPCC grafts that differentiated from murine ASCs in vitro, unlike their freshly isolated islet counterparts, did not survive long-term in syngeneic mice, suggesting that ASC-derived IPCCs have intrinsic survival disadvantage over freshly isolated islets. Indeed, β cells retrieved from IPCC syngrafts underwent faster apoptosis than their islet counterparts. However, blocking both Fas and TNF receptor death pathways inhibited their apoptosis and restored their long-term survival in syngeneic recipients. Furthermore, blocking CD40-CD154 costimulation and Fas/TNF signaling induced long-term IPCC allograft survival in overwhelming majority of recipients. Importantly, Fas-deficient IPCC allografts exhibited certain immune privilege and enjoyed long-term survival in diabetic NOD mice in the presence of CD28/CD40 joint blockade while their islet counterparts failed to do so. Conclusions/Significance Long-term survival of ASC-derived IPCC syngeneic grafts requires blocking Fas and TNF death pathways, whereas blocking both death pathways and CD28/CD40 costimulation is needed for long-term IPCC allograft survival in diabetic NOD mice. Our studies have important clinical implications for treating type 1 diabetes via ASC-derived IPCC transplantation. PMID:22216347

Integrated Farm System Model Version 4.1 and Dairy Gas Emissions Model Version 3.1 software release and distribution

USDA-ARS?s Scientific Manuscript database

Animal facilities are significant contributors of gaseous emissions including ammonia (NH3) and nitrous oxide (N2O). Previous versions of the Integrated Farm System Model (IFSM version 4.0) and Dairy Gas Emissions Model (DairyGEM version 3.0), two whole-farm simulation models developed by USDA-ARS, ...

Comparison of upright LBPP and supine LBNP in terms of cardiovascular and biomechanical parameters to simulate 1/6-G (lunar gravity) and 3/8-G (Martian gravity) activities

NASA Astrophysics Data System (ADS)

Schlabs, Thomas; Rosales-Velderrain, Armando; Ruckstuhl, Heidi; Richardson, Sara E.; Hargens, Alan

Background: Missions of astronauts to Moon and Mars may be planned in the future. From over 40 years of manned spaceflight it is known that the human body experiences cardiovascular and musculoskeletal losses and a decrease in aerobic fitness while exposed to reduced gravity. Because future missions will be much longer than before, further research is needed to improve Earth-based simulations of reduced gravity. Among others, two methods are capable of simu-lating fractional gravity on Earth: upright Lower Body Positive Pressure (LBPP) and supine Lower Body Negative Pressure (LBNP). No previous study has directly compared these two methods to determine which method is better suited to simulate both the biomechanical and cardiovascular responses of performing activity in lunar (1/6-G) and Martian (3/8-G) gravities. Taken previous studies into account and considering the fact that supine posture is closer to the established 10 head-up-tilt lunar simulation, we hypothesized that exercise performed in supine LBNP better simulates the cardiovascular conditions that occur in lunar and Martian gravities. Methods: 12 healthy normal subjects underwent a protocol consisting of resting and walking (0.25 Froude) with LBNP and LBPP. Each protocol was performed in simulated 1/6-G and 3/8-G. Heart-rate (HR), blood pressure, oxygen consumption (VO2), vertical component of the ground reaction force, comfort of the subject and perceived exertion of the subject (Borg Scale) were assessed. The obtained parameters were compared to predicted values for lunar and Martian gravity conditions in order to determine the method that shows the best level of agreement. Results: There was no difference in gait parameters between LBPP and LBNP simulation of lunar and Martian gravity (cadence: P=0.427, normalized stride length: P=0.373, duty fac-tor: P=0.302, and normalized vertical peak force (P=0.064). Mean blood pressure (P=0.398), comfort (P=0.832) and BORG rating (P=0.186) did not differ between the two methods. How-ever, we found that the heart rate (P=0.022) and VO2 (P=0.038) were significantly higher during LBPP (HRM oon =74±3 bpm, HRM ars =80±3 bpm, VO2M oon =4.6±0.22 l*kg-1 *min-1 , VO2M ars =6.17±0.38 l*kg-1 *min-1 ) than in LBNP (HRM oon =72±3 bpm, HRM ars =77±3 bpm, VO2M oon =4.66±0.43 l*kg-1 *min-1 , VO2M ars =5.66±0.42 l*kg-1 *min-1 ). A further analysis of deviation from the predicted parameters (HRM oon =77 bpm, HRM ars =84 bpm, VO2M oon =5.40 l*kg-1 *min-1 , VO2M ars =7.14 l*kg-1 *min-1 ) revealed a smaller deviation for LBPP (∆HR=4 bpm, ∆VO2=0.89 l*kg-1 *min-1 ) as compared to LBNP (∆HR=6 bpm, ∆VO2=1.11 l*kg-1 *min-1 ). Discussion: We conclude that biomechanical characteristics of gait are not different between supine LBNP and upright LBPP. In terms of cardiovascular parameters there are only differ-ences in heart rate and VO2. The higher heart rate during upright LBPP is probably due to a lower preload of the heart; as venous return is attenuated when the subject is positioned upright instead of supine. The higher VO2 during upright LBPP reflects the increased activity of anti-gravity muscles working to keep the upper body in balance without body suspension. Most skeletal muscles are not used when lying at rest in supine LBNP. Considering that values for heart rate and VO2 produced with the LBPP simulation had a smaller deviation from the predicted values than with the LBNP simulation, we conclude that upright LBPP is obviously better suited to simulate both lunar and Martian activities.

Molecular interactions between fenoterol stereoisomers and derivatives and the β₂-adrenergic receptor binding site studied by docking and molecular dynamics simulations.

PubMed

Plazinska, Anita; Kolinski, Michal; Wainer, Irving W; Jozwiak, Krzysztof

2013-11-01

The β2 adrenergic receptor (β2-AR) has become a model system for studying the ligand recognition process and mechanism of the G protein coupled receptors activation. In the present study stereoisomers of fenoterol and some of its derivatives (N = 94 molecules) were used as molecular probes to identify differences in stereo-recognition interactions between β2-AR and structurally similar agonists. The present study aimed at determining the 3D molecular models of the fenoterol derivative-β2-AR complexes. Molecular models of β2-AR have been developed by using the crystal structure of the human β2-AR T4 lysozyme fusion protein with bound (S)-carazolol (PDB ID: 2RH1) and more recently reported structure of a nanobody-stabilized active state of the β2-AR with the bound full agonist BI-167107 (PDB ID: 3P0G). The docking procedure allowed us to study the similarities and differences in the recognition binding site(s) for tested ligands. The agonist molecules occupied the same binding region, between TM III, TM V, TM VI and TM VII. The residues identified by us during docking procedure (Ser203, Ser207, Asp113, Lys305, Asn312, Tyr308, Asp192) were experimentally indicated in functional and biophysical studies as being very important for the agonist-receptor interactions. Moreover, the additional space, an extension of the orthosteric pocket, was identified and described. Furthermore, the molecular dynamics simulations were used to study the molecular mechanism of interaction between ligands ((R,R')- and (S,S')-fenoterol) and β2-AR. Our research offers new insights into the ligand stereoselective interaction with one of the most important GPCR member. This study may also facilitate the design of improved selective medications, which can be used to treat, prevent and control heart failure symptoms.

Effects of future climate change, CO2 enrichment, and vegetation structure variation on hydrological processes in China

USGS Publications Warehouse

Zhu, Qiuan; Jiang, Hong; Peng, Changhui; Liu, Jinxun; Fang, Xiuqin; Wei, Xiaohua; Liu, Shirong; Zhou, Guomo

2012-01-01

Investigating the relationship between factors (climate change, atmospheric CO2 concentrations enrichment, and vegetation structure) and hydrological processes is important for understanding and predicting the interaction between the hydrosphere and biosphere. The Integrated Biosphere Simulator (IBIS) was used to evaluate the effects of climate change, rising CO2, and vegetation structure on hydrological processes in China at the end of the 21st century. Seven simulations were implemented using the assemblage of the IPCC climate and CO2 concentration scenarios, SRES A2 and SRES B1. Analysis results suggest that (1) climate change will have increasing effects on runoff, evapotranspiration (ET), transpiration (T), and transpiration ratio (transpiration/evapotranspiration, T/E) in most hydrological regions of China except in the southernmost regions; (2) elevated CO2 concentrations will have increasing effects on runoff at the national scale, but at the hydrological region scale, the physiology effects induced by elevated CO2 concentration will depend on the vegetation types, climate conditions, and geographical background information with noticeable decreasing effects shown in the arid Inland region of China; (3) leaf area index (LAI) compensation effect and stomatal closure effect are the dominant factors on runoff in the arid Inland region and southern moist hydrological regions, respectively; (4) the magnitudes of climate change (especially the changing precipitation pattern) effects on the water cycle are much larger than those of the elevated CO2 concentration effects; however, increasing CO2 concentration will be one of the most important modifiers to the water cycle; (5) the water resource condition will be improved in northern China but depressed in southernmost China under the IPCC climate change scenarios, SRES A2 and SRES B1.

Accuracy requirements. [for monitoring of climate changes

NASA Technical Reports Server (NTRS)

Delgenio, Anthony

1993-01-01

Satellite and surface measurements, if they are to serve as a climate monitoring system, must be accurate enough to permit detection of changes of climate parameters on decadal time scales. The accuracy requirements are difficult to define a priori since they depend on unknown future changes of climate forcings and feedbacks. As a framework for evaluation of candidate Climsat instruments and orbits, we estimate the accuracies that would be needed to measure changes expected over two decades based on theoretical considerations including GCM simulations and on observational evidence in cases where data are available for rates of change. One major climate forcing known with reasonable accuracy is that caused by the anthropogenic homogeneously mixed greenhouse gases (CO2, CFC's, CH4 and N2O). Their net forcing since the industrial revolution began is about 2 W/sq m and it is presently increasing at a rate of about 1 W/sq m per 20 years. Thus for a competing forcing or feedback to be important, it needs to be of the order of 0.25 W/sq m or larger on this time scale. The significance of most climate feedbacks depends on their sensitivity to temperature change. Therefore we begin with an estimate of decadal temperature change. Presented are the transient temperature trends simulated by the GISS GCM when subjected to various scenarios of trace gas concentration increases. Scenario B, which represents the most plausible near-term emission rates and includes intermittent forcing by volcanic aerosols, yields a global mean surface air temperature increase Delta Ts = 0.7 degrees C over the time period 1995-2015. This is consistent with the IPCC projection of about 0.3 degrees C/decade global warming (IPCC, 1990). Several of our estimates below are based on this assumed rate of warming.

Photosynthetic and antioxidant responses of Liquidambar formosana and Schima superba seedlings to sulfuric-rich and nitric-rich simulated acid rain.

PubMed

Chen, Juan; Wang, Wen-Hua; Liu, Ting-Wu; Wu, Fei-Hua; Zheng, Hai-Lei

2013-03-01

To study whether differential responses occur in photosynthesis and antioxidant system for seedlings of Liquidambar formosana, an acid rain (AR)-sensitive tree species and Schima superba, an AR-tolerant tree species treated with three types of pH 3.0 simulated AR (SiAR) including sulfuric-rich (S-SiAR), nitric-rich (N-SiAR), sulfate and nitrate mixed (SN-SiAR), we investigated the changes of leaf necrosis, chlorophyll content, soluble protein and proline content, photosynthesis and chlorophyll fluorescence characteristics, reactive oxygen species production, membrane lipid peroxidation, small molecular antioxidant content, antioxidant enzyme activities and related protein expressions. Our results showed that SiAR significantly caused leaf necrosis, inhibited photosynthesis, induced superoxide radical and hydrogen peroxide generation, aggravated membrane lipid peroxidation, changed antioxidant enzyme activities, modified related protein expressions such as Cu/Zn superoxide dismutase (SOD), l-ascorbate peroxidase (APX, EC 1. 11. 1. 11), glutathione S transferase (GST, EC 2. 5. 1. 18) and Rubisco large subunit (RuBISCO LSU), altered non-protein thiols (NPT) and glutathione (GSH) content in leaves of L. formosana and S. superba. Taken together, we concluded that the damages caused by SiAR in L. formosana were more severe and suffered from more negative impacts than in S. superba. S-SiAR induced more serious damages for the plants than did SN-SiAR and N-SiAR. Crown Copyright © 2013. Published by Elsevier Masson SAS. All rights reserved.

Indirect effect of changing aerosol concentrations on methane and ozone radiative forcing

NASA Astrophysics Data System (ADS)

Rowlinson, Matthew; Rap, Alexandru; Arnold, Steve; Forster, Piers; Chipperfield, Martyn

2017-04-01

Atmospheric aerosols interact with climate in number of complex ways and quantifying the overall effect remains the dominant uncertainty in estimating anthropogenic climate forcing (IPCC, 2013). The radiative forcing (RF) caused by the direct effect of aerosol interacting with radiation is estimated at -0.35 (-0.85 to +0.15) Wm-2, while cloud-aerosol interactions are estimated at -0.45 (-1.2 to 0.0) Wm-2 (IPCC, 2013). The net impact is a cooling with an effective radiative forcing (ERF) of 0.9 (-1.9 to -0.1) Wm-2 (IPCC, 2013). One effect of aerosols which has not been well evaluated is their effect on atmospheric chemistry. Atmospheric aerosols provide a surface for homogeneous reactions to occur, altering reactions rates and the availability of oxidants, thereby influencing the removal/production of radiatively important species such as methane (CH4) and tropospheric ozone (O3). Oxidants such as the hydroxyl radical (OH) determine the atmospheric lifetime and hence burden of CH4, therefore changes to atmospheric aerosols which impact oxidation chemistry will also influence RF due to CH4. This effect could enhance or offset the negative RF of aerosols, depending on how the individual aerosol changes availability of oxidants. Quantifying the importance of this mechanism for RF is necessary to provide accurate estimates of the effect of aerosols, and assess relative effectiveness of measures to decrease aerosol emissions and precursors. Using a sophisticated aerosol micro-physics model (GLOMAP) coupled to the TOMCAT three-dimensional chemical transport model, we separately simulate changes in atmospheric composition resulting from a 50% decline in anthropogenic emissions of black carbon aerosol (BC), volatile organic compounds (VOCs) and anthropogenic precursors of sulphate and nitrate. The impact of changes to each aerosol on lifetime of CH4 is then calculated to establish the resulting impact on CH4 burden and RF. Cutting global anthropogenic SO2 emissions by 50% decreases atmospheric sulpate concentrations by 44% after 2 years, while increasing global OH concentrations by 0.9%. CH4 lifetime is reduced by approximately 50 days as a result, leading to a decrease in CH4 burden of 38ppb. NOx is anticipated to have a similar but much larger effect (Matsui and Koike 2016). The Edwards and Slingo offline radiation model is also used to calculate changes to direct and indirect aerosol forcing. Presented here is the net RF change following 50% emission decrease of each aerosol or precursors, accounting for the direct and indirect aerosol effect as well as indirect effects via oxidation chemistry on the RF due to CH4 and tropospheric O3.

KDM4B and KDM4A promote endometrial cancer progression by regulating androgen receptor, c-myc, and p27kip1

PubMed Central

Kwan, Suet-Ying; Chen, Limo; Chen, Jin-Hong; Ying, Zuo-Lin; Zhou, Ye; Gu, Wei; Wang, Li-Hua; Cheng, Wei-Wei; Zeng, Jianfang; Wan, Xiao-Ping; Mok, Samuel C.; Wong, Kwong-Kwok; Bao, Wei

2015-01-01

Epidemiological evidence suggests that elevated androgen levels and genetic variation related to the androgen receptor (AR) increase the risk of endometrial cancer (EC). However, the role of AR in EC is poorly understood. We report that two members of the histone demethylase KDM4 family act as major regulators of AR transcriptional activityin EC. In the MFE-296 cell line, KDM4B and AR upregulate c-myc expression, while in AN3CA cells KDM4A and AR downregulate p27kip1. Additionally, KDM4B expression is positively correlated with AR expression in EC cell lines with high baseline AR expression, while KDM4A and AR expression are positively correlated in low-AR cell lines. In clinical specimens, both KDM4B and KDM4A expression are significantly higher in EC tissues than that in normal endometrium. Finally, patients with alterations in AR, KDM4B, KDM4A, and c-myc have poor overall and disease-free survival rates. Together, these findings demonstrate that KDM4B and KDM4A promote EC progression by regulating AR activity. PMID:26397136

A Projection of Changes in Landfilling Atmospheric River Frequency and Extreme Precipitation over Western North America from the Large Ensemble CESM Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagos, Samson M.; Leung, Lai-Yung R.; Yoon, Jin-Ho

Simulations from the Community Earth System Model Large Ensemble project are analyzed to investigate the impact of global warming on atmospheric rivers (ARs). The model has notable biases in simulating the subtropical jet position and the relationship between extreme precipitation and moisture transport. After accounting for these biases, the model projects an ensemble mean increase of 35% in the number of landfalling AR days between the last twenty years of the 20th and 21st centuries. However, the number of AR associated extreme precipitation days increases only by 28% because the moisture transport required to produce extreme precipitation also increases withmore » warming. Internal variability introduces an uncertainty of ±8% and ±7% in the projected changes in AR days and associated extreme precipitation days. In contrast, accountings for model biases only change the projected changes by about 1%. The significantly larger mean changes compared to internal variability and to the effects of model biases highlight the robustness of AR responses to global warming.« less

Simulations of Liners and Test Objects for a New Atlas Advanced Radiography Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. V. Morgan; S. Iversen; R. A. Hilko

2002-06-01

The Advanced Radiographic Source (ARS) will improve the data significantly due to its smaller source width. Because of the enhanced ARS output, larger source-to-object distances are a reality. The harder ARS source will allow radiography of thick high-Z targets. The five different spectral simulations resulted in similar imaging detector weighted transmission. This work used a limited set of test objects and imaging detectors. Other test objects and imaging detectors could possibly change the MVp-sensitivity result. The effect of material motion blur must be considered for the ARS due to the expected smaller X-ray source size. This study supports the originalmore » 1.5-MVp value.« less

Development of methane emission factors for enteric fermentation in cattle from Benin using IPCC Tier 2 methodology.

PubMed

Kouazounde, J B; Gbenou, J D; Babatounde, S; Srivastava, N; Eggleston, S H; Antwi, C; Baah, J; McAllister, T A

2015-03-01

The objective of this study was to develop emission factors (EF) for methane (CH4) emissions from enteric fermentation in cattle native to Benin. Information on livestock characteristics and diet practices specific to the Benin cattle population were gathered from a variety of sources and used to estimate EF according to Tier 2 methodology of the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories. Most cattle from Benin are Bos taurus represented by Borgou, Somba and Lagune breeds. They are mainly multi-purpose, being used for production of meat, milk, hides and draft power and grazed in open pastures and crop lands comprising tropical forages and crops. Estimated enteric CH4 EFs varied among cattle breeds and subcategory owing to differences in proportions of gross energy intake expended to meet maintenance, production and activity. EFs ranged from 15.0 to 43.6, 16.9 to 46.3 and 24.7 to 64.9 kg CH4/head per year for subcategories of Lagune, Somba and Borgou cattle, respectively. Average EFs for cattle breeds were 24.8, 29.5 and 40.2 kg CH4/head per year for Lagune, Somba and Borgou cattle, respectively. The national EF for cattle from Benin was 39.5 kg CH4/head per year. This estimated EF was 27.4% higher than the default EF suggested by IPCC for African cattle with the exception of dairy cattle. The outcome of the study underscores the importance of obtaining country-specific EF to estimate global enteric CH4 emissions.

Assessing the capability of high resolution climatic model experiments to simulate Mediterranean cyclonic tracks

NASA Astrophysics Data System (ADS)

Hatzaki, M.; Flocas, H. A.; Giannakopoulos, C.; Kostopoulou, E.; Kouroutzoglou, I.; Keay, K.; Simmonds, I.

2010-09-01

In this study, a comparison of a reanalysis driven simulation to a GCM driven simulation of a regional climate model is performed in order to assess the model's ability to capture the climatic characteristics of cyclonic tracks in the Mediterranean in the present climate. The ultimate scope of the study will be to perform a future climate projection related to cyclonic tracks in order to better understand and assess climate change in the Mediterranean. The climatology of the cyclonic tracks includes inter-monthly variations, classification of tracks according to their origin domain, dynamic and kinematic characteristics, as well as trend analysis. For this purpose, the ENEA model is employed based on PROTHEUS system composed of the RegCM atmospheric regional model and the MITgcm ocean model, coupled through the OASIS3 flux coupler. These model data became available through the EU Project CIRCE which aims to perform, for the first time, climate change projections with a realistic representation of the Mediterranean Sea. Two experiments are employed; a) the ERA402 with lateral Boundary conditions from ERA40 for the 43-year period 1958-2000, and b) the EH5OM_20C3M where the lateral boundary conditions for the atmosphere (1951-2000) are taken from the ECHAM5-MPIOM 20c3m global simulation (run3) included in the IPCC-AR4. The identification and tracking of cyclones is performed with the aid of the Melbourne University algorithm (MS algorithm), according to the Lagrangian perspective. MS algorithm characterizes a cyclone only if a vorticity maximum could be connected with a local pressure minimum. This approach is considered to be crucial, since open lows are also incorporated into the storm life-cycle, preventing possible inappropriate time series breaks, if a temporary weakening to an open-low state occurs. The model experiments verify that considerable inter-monthly variations of track density occur in the Mediterranean region, consistent with previous studies. The classification of the tracks according to their origin domain show that the vast majority originate within the examined area itself. The study of the kinematic and dynamic parameters of tracks according to their origin demonstrate that deeper cyclones follow the SW track. ACKNOWLEDGMENTS: M. Hatzaki would like to thank the Greek State Scholarships Foundation for financial support through the program of postdoctoral research. The support of EU-FP6 project CIRCE Integrated Project-Climate Change and Impact Research: the Mediterranean Environment (http://www.circeproject.eu) for climate model data provision is also greatly acknowledged.

Identification of key binding site residues of MCT1 for AR-C155858 reveals the molecular basis of its isoform selectivity.

PubMed

Nancolas, Bethany; Sessions, Richard B; Halestrap, Andrew P

2015-02-15

The proton-linked monocarboxylate transporters (MCTs) are required for lactic acid transport into and out of all mammalian cells. Thus, they play an essential role in tumour cells that are usually highly glycolytic and are promising targets for anti-cancer drugs. AR-C155858 is a potent MCT1 inhibitor (Ki ~2 nM) that also inhibits MCT2 when associated with basigin but not MCT4. Previous work [Ovens, M.J. et al. (2010) Biochem. J. 425, 523-530] revealed that AR-C155858 binding to MCT1 occurs from the intracellular side and involves transmembrane helices (TMs) 7-10. In the present paper, we generate a molecular model of MCT4 based on our previous models of MCT1 and identify residues in the intracellular substrate-binding cavity that differ significantly between MCT4 and MCT1/MCT2 and so might account for differences in inhibitor binding. We tested their involvement using site-directed mutagenesis (SDM) of MCT1 to change residues individually or in combination with their MCT4 equivalent and determined inhibitor sensitivity following expression in Xenopus oocytes. Phe360 and Ser364 were identified as important for AR-C155858 binding with the F360Y/S364G mutant exhibiting >100-fold reduction in inhibitor sensitivity. To refine the binding site further, we used molecular dynamics (MD) simulations and additional SDM. This approach implicated six more residues whose involvement was confirmed by both transport studies and [3H]-AR-C155858 binding to oocyte membranes. Taken together, our data imply that Asn147, Arg306 and Ser364 are important for directing AR-C155858 to its final binding site which involves interaction of the inhibitor with Lys38, Asp302 and Phe360 (residues that also play key roles in the translocation cycle) and also Leu274 and Ser278.

Identification of key binding site residues of MCT1 for AR-C155858 reveals the molecular basis of its isoform selectivity

PubMed Central

Nancolas, Bethany; Sessions, Richard B.; Halestrap, Andrew P.

2014-01-01

The proton-linked monocarboxylate transporters (MCTs) are required for lactic acid transport into and out of all mammalian cells. Thus, they play an essential role in tumour cells that are usually highly glycolytic and are promising targets for anti-cancer drugs. AR-C155858 is a potent MCT1 inhibitor (Ki ~2 nM) that also inhibits MCT2 when associated with basigin but not MCT4. Previous work [Ovens, M.J. et al. (2010) Biochem. J. 425, 523–530] revealed that AR-C155858 binding to MCT1 occurs from the intracellular side and involves transmembrane helices (TMs) 7–10. In the present paper, we generate a molecular model of MCT4 based on our previous models of MCT1 and identify residues in the intracellular substrate-binding cavity that differ significantly between MCT4 and MCT1/MCT2 and so might account for differences in inhibitor binding. We tested their involvement using site-directed mutagenesis (SDM) of MCT1 to change residues individually or in combination with their MCT4 equivalent and determined inhibitor sensitivity following expression in Xenopus oocytes. Phe360 and Ser364 were identified as important for AR-C155858 binding with the F360Y/S364G mutant exhibiting >100-fold reduction in inhibitor sensitivity. To refine the binding site further, we used molecular dynamics (MD) simulations and additional SDM. This approach implicated six more residues whose involvement was confirmed by both transport studies and [3H]-AR-C155858 binding to oocyte membranes. Taken together, our data imply that Asn147, Arg306 and Ser364 are important for directing AR-C155858 to its final binding site which involves interaction of the inhibitor with Lys38, Asp302 and Phe360 (residues that also play key roles in the translocation cycle) and also Leu274 and Ser278. PMID:25437897

Modeling Holocene Barrier Island Morphodynamics and Potential Future Response to Sea- Level Rise, Outer Banks, North Carolina

NASA Astrophysics Data System (ADS)

Moore, L. J.; List, J. H.; Williams, S. J.; Stolper, D.

2006-12-01

A morphological-behavior model, GEOMBEST, which simulates the evolution of coastal morphology and stratigraphy resulting from changes in sea level and sediment supply provides insight into how barriers evolve over time scales ranging from decades to millenia. The model is based upon behavior rules originating from "Bruun rule" concepts, with additional parameters to allow simulation of more complex real-world scenarios. Morphological evolution in the model is driven by disequilibrium between the shoreface and a user-specified theoretical equilibrium profile that maintains its vertical position relative to sea level. As sea level continues rising to an estimated 48 cm above current MSL by AD 2100 (IPCC 2001) and hurricanes of potentially greater intensity impact the coast, barrier islands will respond either by transgressing across underlying strata or by disintegrating and ultimately submerging. Recent studies suggest that some barriers along the U.S. East Coast will break up and become submerged within decades. Other studies show that barriers in Louisiana have already submerged while others are in the process of narrowing in place and submerging. Several factors determine barrier island response to sea-level rise. These include initial topography and morphology of the barrier, underlying geologic framework, availability and supply of sediment, rate of sea-level rise, frequency and intensity of coastal storms, and anthropogenic modifications to the coast. Sensitivity analyses conducted in GEOMBEST suggest that of these factors, barrier-island response is most sensitive to the rate of sea-level rise. The Holocene evolution of the Outer Banks and potential future responses to sea-level rise are explored for a 25-km stretch of coast between Rodanthe and Cape Hatteras, NC using GEOMBEST. An 8500-year hindcast simulation for the study area reproduces closely the morphology and stratigraphy of the modern barrier with approximately 5 x 109 m3 excavated from the Pleistocene substrate, liberating a volume of material sufficient to construct Diamond Shoals. This hindcast simulation serves as the basis for forward simulations of potential future barrier island evolution. A series of model runs based on the low- (0.09 m), mid- (0.48 m) and upper- (0.88 m) range of IPCC (2001) estimates for sea-level rise by the year 2100, suggest the barrier would migrate at rates of approximately 2, 6 and 10 m/yr, respectively. The latter two results would represent an increase over modern long-term erosion rates in the study area, which serve as a proxy for migration rates. Model simulations of barrier response to 4 and 6 m of sea-level rise by AD 2100 (Overpeck et al., 2006), result in model-generated migration rates of 43 and 68 m/yr, respectively. These rates far exceed the highest average long-term barrier island erosion rates observed today along the Louisiana Coast where the Chandeleur Islands disintegrated in response to Hurricane Katrina. If observations in Louisiana can be applied to barrier islands in North Carolina, then we can expect the Outer Banks to become vulnerable to disintegration when migration rates reach approximately 15-20 m/yr. The five forward simulations for the study area suggest rates in this range may be achieved in the Outer Banks if sea-level rise by AD 2100 exceeds IPCC (2001) estimates.

Regional Climate and Streamflow Projections in North America Under IPCC CMIP5 Scenarios

NASA Astrophysics Data System (ADS)

Chang, H. I.; Castro, C. L.; Troch, P. A. A.; Mukherjee, R.

2014-12-01

The Colorado River system is the predominant source of water supply for the Southwest U.S. and is already fully allocated, making the region's environmental and economic health particularly sensitive to annual and multi-year streamflow variability. Observed streamflow declines in the Colorado Basin in recent years are likely due to synergistic combination of anthropogenic global warming and natural climate variability, which are creating an overall warmer and more extreme climate. IPCC assessment reports have projected warmer and drier conditions in arid to semi-arid regions (e.g. Solomon et al. 2007). The NAM-related precipitation contributes to substantial Colorado streamflows. Recent climate change studies for the Southwest U.S. region project a dire future, with chronic drought, and substantially reduced Colorado River flows. These regional effects reflect the general observation that climate is being more extreme globally, with areas climatologically favored to be wet getting wetter and areas favored to be dry getting drier (Wang et al. 2012). Multi-scale downscaling modeling experiments are designed using recent IPCC AR5 global climate projections, which incorporate regional climate and hydrologic modeling components. The Weather Research and Forecasting model (WRF) has been selected as the main regional modeling tool; the Variable Infiltration Capacity model (VIC) will be used to generate streamflow projections for the Colorado River Basin. The WRF domain is set up to follow the CORDEX-North America guideline with 25km grid spacing, and VIC model is individually calibrated for upper and lower Colorado River basins in 1/8° resolution. The multi-scale climate and hydrology study aims to characterize how the combination of climate change and natural climate variability is changing cool and warm season precipitation. Further, to preserve the downscaled RCM sensitivity and maintain a reasonable climatology mean based on observed record, a new bias correction technique is applied when using the RCM climatology to the streamflow model. Of specific interest is how major droughts associated with La Niña-like conditions may worsen in the future, as these are the times when the Colorado River system is most critically stressed and would define the "worst case" scenario for water resource planning.

Teaching binocular indirect ophthalmoscopy to novice residents using an augmented reality simulator.

PubMed

Rai, Amandeep S; Rai, Amrit S; Mavrikakis, Emmanouil; Lam, Wai Ching

2017-10-01

To compare the traditional teaching approach of binocular indirect ophthalmoscopy (BIO) to the EyeSI augmented reality (AR) BIO simulator. Prospective randomized control trial. 28 post-graduate year one (PGY1) ophthalmology residents. Residents were recruited at the 2012 Toronto Ophthalmology Residents Introductory Course (TORIC). 15 were randomized to conventional teaching (Group 1), and 13 to augmented reality simulator training (Group 2). 3 vitreoretinal fellows were enrolled to serve as experts. Evaluations were completed on the simulator, with 3 tasks, and outcome measures were total raw score, total time elapsed, and performance. Following conventional training, Group 1 residents were outperformed by vitreoretinal fellows with respect to all 3 outcome measures. Following AR training, Group 2 residents demonstrated superior total scores and performance compared to Group 1 residents. Once the Group 1 residents also completed the AR BIO training, there was a significant improvement compared to their baseline scores, and were now on par with Group 2 residents. This study provides construct validity for the EyeSI AR BIO simulator and demonstrates that it may be superior to conventional BIO teaching for novice ophthalmology residents. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Defect printability of ArF alternative phase-shift mask: a critical comparison of simulation and experiment

NASA Astrophysics Data System (ADS)

Ozawa, Ken; Komizo, Tooru; Ohnuma, Hidetoshi

2002-07-01

An alternative phase shift mask (alt-PSM) is a promising device for extending optical lithography to finer design rules. There have been few reports, however, on the mask's ability to identify phase defects. We report here an alt-PSM of a single-trench type with undercut for ArF exposure, with programmed phase defects used to evaluate defect printability by measuring aerial images with a Zeiss MSM193 measuring system. The experimental results are simulated using the TEMPEST program. First, a critical comparison of the simulation and the experiment is conducted. The actual measured topographies of quartz defects are used in the simulation. Moreover, a general simulation study on defect printability using an alt-PSM for ArF exposure is conducted. The defect dimensions, which produce critical CD errors, are determined by simulation that takes into account the full 3-dimensional structure of phase defects as well as a simplified structure. The critical dimensions of an isolated bump defect identified by the alt-PSM of a single-trench type with undercut for ArF exposure are 300 nm in bottom dimension and 74 degrees in height (phase) for the real shape, where the depth of wet-etching is 100 nm and the CD error limit is +/- 5 percent.

Effects of HO-/MeO-PBDEs on androgen receptor: in vitro investigation and helix 12-involved MD simulation.

PubMed

Wang, Xiaoxiang; Yang, Huaiyu; Hu, Xinxin; Zhang, Xiaowei; Zhang, Qiansen; Jiang, Hualiang; Shi, Wei; Yu, Hongxia

2013-10-15

Hydroxylated and methoxylated polybrominated diphenyl ethers (HO-/MeO-PBDEs) have received increasing attention for their potential endocrine disrupting activities and widely environmental distribution. However, little information is available for the anti-androgenic activities, and the molecular mechanism of interactions with androgen receptor (AR) is not fully understood. In the present study, cell line assay and computational simulation were integrated to systematically explore the molecular mechanism of interactions between chemicals and AR. The metabolites with similar molecular structures exhibited different anti-androgenic activity while none of them showed androgenic activity. According to the multisystem molecular dynamics simulation, minute differences in the structure of ligands induced dramatic different conformational transition of AR-ligand binding domain (LBD). The Helix12 (H12) component of active ligands occupied AR-LBD could become stable, but this component continued to fluctuate in inactive ligands occupied AR-LBD. Settling time and reposition of H12 obtained in dynamics process are important factors governing anti-androgenic activities. The related settling times were characteristic of anti-androgenic potencies of the tested chemicals. Overall, in our study, the stable reposition of H12 is characterized as a computational mark for identifying AR antagonists from PBDE metabolites, or even other various environmental pollutants.

Domain size sensitivities of landfalling eastern Pacific atmospheric rivers

NASA Astrophysics Data System (ADS)

McClenny, E. E.; Ullrich, P. A.; Grotjahn, R.; Guan, B.; Waliser, D. E.

2017-12-01

Atmospheric rivers (ARs) concentrate a majority of mid-latitude latent heat transport into narrow bands. ARs making landfall along the North American coast typically originate in the waters surrounding Hawaii. We explore here the effects of explicitly simulating this "genesis region" on AR characteristics. We do this using two models and three domains centered on the North American coast. The Weather Research and Forecast (WRF) model, forced by National Center for Environmental Prediction Final Reanalysis data, provides a representative regional model. The simulation domains include: 1. Just off the coastline (100-130W), 2. The coastline to the Pacific just east of Hawaii (100-155W), and 3. The coastline to the Pacific west of Hawaii (100-180W). The Variable Resolution Community Earth System Model simulates ARs while preserving global interactions. In this global model, "domain" refers to the mesh refinement region, each of which corresponds to one of the three previously described WRF domains. We compare ARs from the wet season (October-April) for water years 2009-2017 in the test models against those found in the Modern Era Retrospective Reanalysis 2 (MERRA2). We objectively detect events with the global AR detection algorithm introduced in Guan and Waliser (2015). Comparisons between all model configurations and the reference MERRA2 data will be assessed by characteristics including landfall location (meridional distributions, including quartile ranges and standard deviations of landfalls across the coast), as well as vapor flux and precipitation (in terms of both the contribution of ARs to the larger regional climatology and any differences in the intensity of individual AR events across runs).

ID4 promotes AR expression and blocks tumorigenicity of PC3 prostate cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komaragiri, Shravan Kumar; Bostanthirige, Dhanushka H.; Morton, Derrick J.

Deregulation of tumor suppressor genes is associated with tumorigenesis and the development of cancer. In prostate cancer, ID4 is epigenetically silenced and acts as a tumor suppressor. In normal prostate epithelial cells, ID4 collaborates with androgen receptor (AR) and p53 to exert its tumor suppressor activity. Previous studies have shown that ID4 promotes tumor suppressive function of AR whereas loss of ID4 results in tumor promoter activity of AR. Previous study from our lab showed that ectopic ID4 expression in DU145 attenuates proliferation and promotes AR expression suggesting that ID4 dependent AR activity is tumor suppressive. In this study, wemore » examined the effect of ectopic expression of ID4 on highly malignant prostate cancer cell, PC3. Here we show that stable overexpression of ID4 in PC3 cells leads to increased apoptosis and decreased cell proliferation and migration. In addition, in vivo studies showed a decrease in tumor size and volume of ID4 overexpressing PC3 cells, in nude mice. At the molecular level, these changes were associated with increased androgen receptor (AR), p21, and AR dependent FKBP51 expression. At the mechanistic level, ID4 may regulate the expression or function of AR through specific but yet unknown AR co-regulators that may determine the final outcome of AR function. - Highlights: • ID4 expression induces AR expression in PC3 cells, which generally lack AR. • ID4 expression increased apoptosis and decreased cell proliferation and invasion. • Overexpression of ID4 reduces tumor growth of subcutaneous xenografts in vivo. • ID4 induces p21 and FKBP51 expression- co-factors of AR tumor suppressor activity.« less

Projected Risk of Flooding Disaster over China in 21st Century Based on CMIP5 Models

NASA Astrophysics Data System (ADS)

Li, Rouke; Xu, Ying

2016-04-01

Based on the simulations from CMIP5 models, using climate indices which have high correlation with historical disaster data, and in combination with terrain elevation data and the socio-economic data, to project the flooding disaster risk, the vulnerability of flooding hazard affected body and the risk of flooding hazard respectively during the near term(2015-2039), medium term(2045-2069) and long term(2075-2099) under RCP8.5. According to the IPCC AR5 WGII, we used risk evaluation model of disaster: R=E*H*V. R on behalf of disaster risk index. H, E and V express risk, exposure and vulnerability respectively. The results show that the extreme flooding disaster risk will gradually increase during different terms in the future, and regions with high risk level of flooding hazard are might mainly located in southeastern and eastern China. Under the RCP8.5 greenhouse gas emissions scenario, the high risk of flooding disaster in future might mainly appear in eastern part of Sichuan, most of North China, and major of East China. Compared with the baseline period,21st century forward, although the occurrence of floods area changes little, the regional strong risk will increase during the end of the 21st century. Due to the coarse resolution of climate models and the methodology for determining weight coefficients, large uncertainty still exists in the projection of the flooding disaster risk.

Impact of Lateral Mixing in the Ocean on El Nino in Fully Coupled Climate Models

NASA Astrophysics Data System (ADS)

Gnanadesikan, A.; Russell, A.; Pradal, M. A. S.; Abernathey, R. P.

2016-02-01

Given the large number of processes that can affect El Nino, it is difficult to understand why different climate models simulate El Nino differently. This paper focusses on the role of lateral mixing by mesoscale eddies. There is significant disagreement about the value of the mixing coefficient ARedi which parameterizes the lateral mixing of tracers. Coupled climate models usually prescribe small values of this coefficient, ranging between a few hundred and a few thousand m2/s. Observations, however, suggest values that are much larger. We present a sensitivity study with a suite of Earth System Models that examines the impact of varying ARedi on the amplitude of El Nino. We examine the effect of varying a spatially constant ARedi over a range of values similar to that seen in the IPCC AR5 models, as well as looking at two spatially varying distributions based on altimetric velocity estimates. While the expectation that higher values of ARedi should damp anomalies is borne out in the model, it is more than compensated by a weaker damping due to vertical mixing and a stronger response of atmospheric winds to SST anomalies. Under higher mixing, a weaker zonal SST gradient causes the center of convection over the Warm pool to shift eastward and to become more sensitive to changes in cold tongue SSTs . Changes in the SST gradient also explain interdecadal ENSO variability within individual model runs.

Interplay Between Cytoplasmic and Nuclear Androgen Receptor Splice Variants Mediate Castration Resistance

PubMed Central

Zhan, Yang; Zhang, Guanyi; Wang, Xiaojie; Qi, Yanfeng; Bai, Shanshan; Li, Dongying; Ma, Tianfang; Sartor, Oliver; Flemington, Erik K.; Zhang, Haitao; Lee, Peng; Dong, Yan

2016-01-01

Androgen receptor splice variants (AR-Vs) are implicated in resistance of prostate cancer to androgen-directed therapies. When expressed alone in cells, some AR-Vs (e.g., AR-V7) localize primarily to the nucleus, whereas others (e.g., AR-V1, AR-V4, and AR-V6) localize mainly to the cytoplasm. Significantly, the latter are often co-expressed with the nucleus-predominant AR-Vs and the full-length AR (AR-FL). An important question to be addressed is whether the cytoplasmic-localized AR-Vs play a role in castration-resistant prostate cancer (CRPC) through interaction with the nucleus-predominant AR-Vs and AR-FL. Here, it is demonstrated that AR-V1, -V4, and -V6 can dimerize with both AR-V7 and AR-FL. Consequently, AR-V7 and androgen-bound AR-FL induced nuclear localization of AR-V1, -V4, and -V6, and these variants, in turn, mitigated the ability of the anti-androgen enzalutamide to inhibit androgen-induced AR-FL nuclear localization. Interestingly, the impact of nuclear localization of AR-V4 and -V6 on AR transactivation differs from that of AR-V1. Nuclear localization leads to an increased ability of AR-V4 and -V6 to transactivate both canonical AR targets and AR-V-specific targets and to confer castration-resistant cell growth. However, while AR-V1, which lacks inherent transcriptional activity, appears to activate AR-FL in an androgen-independent manner, it significantly antagonizes AR-V7 transactivation. Together, these data demonstrate that the complex interactions among different AR-Vs and AR-FL play a significant role in castration resistant disease. Implications This study suggests important consequences for clinical castration resistance due to simultaneous expression of AR-FL and AR-Vs in patient tumors and suggests that dissecting these interactions should help develop effective strategies to disrupt AR-V signaling. PMID:27671337

Interaction of AR and iNOS in lens epithelial cell: A new pathogenesis and potential therapeutic targets of diabetic cataract.

PubMed

Li, Xue; Liu, Wenping; Huang, Xinduo; Xiong, Jianping; Wei, Xiaoyong

2017-02-01

Although there is significant interest in revealing the role of aldose reductase (AR) and inducible nitric oxide synthase (iNOS) in diabetic cataract (DC), the interaction of AR and iNOS remains unknown. The aim of this study is to investigate the pathogenesis mechanisms and explore as a new potential therapeutic targets for DC. This study investigated the interaction of AR-iNOS through the methods of enzyme kinetics, molecular docking and molecular dynamics simulation, co-immunoprecipitation and fluorescence resonance energy transfer (FRET). The IC50 of AR for inhibition of iNOS activity is 0.04 μM, and the IC50 of iNOS for inhibition of AR activity is 0.042 μM through enzyme kinetics; the interface showed that ARG99 on AR and GLU317 on iNOS played the key roles in the interaction of AR-iNOS predicted by molecular docking and molecular dynamics simulation. Co-immunoprecipitation of protein complexes in human lens epithelial cell (HLEC) demonstrated that AR could association with iNOS in cell; and the interaction distance of AR-iNOS was 6.50 ± 0.22 nm detected by FRET. This study exhibited a direct inhibition interaction between AR and iNOS in HLECs. It is the first report of inhibition interaction between AR and iNOS, suggesting a new pathophysiological mechanism and providing a new insight into the therapeutic mechanism of DC. Copyright © 2017 Elsevier Inc. All rights reserved.

Collisional excitation of ArH+ by hydrogen atoms

NASA Astrophysics Data System (ADS)

Dagdigian, Paul J.

2018-06-01

The rotational excitation of the 36ArH+ ion in collisions with hydrogen atoms is investigated in this work. The potential energy surface (PES) describing the 36ArH+-H interaction, with the ion bond length r fixed at the average of r over the radial v = 0 vibrational state distribution, was obtained with a coupled cluster method that included single, double, and (perturbatively) triple excitations [RCCSD(T)]. A deep minimum (De = 3135 cm-1) in the PES was found in linear H-ArH+ geometry at an ion-atom separation Re = 4.80a0. Energy-dependent cross-sections and rate coefficients as a function of temperature for this collision pair were computed in close-coupling (CC) calculations. Since the PES possesses a deep well, this is a good system to test the performance of the quantum statistical (QS) method developed by Manolopoulos and co-workers as a more efficient method to compute the cross-sections. Good agreement was found between rate coefficients obtained by the CC and QS methods at several temperatures. In a simple application, the excitation of ArH+ is simulated for conditions under which this ion is observed in absorption.

Complexity and interdisciplinary approaches to environmental research

NASA Astrophysics Data System (ADS)

Kammen, Daniel M.

2013-03-01

The launch of volume 8 of Environmental Research Letters (ERL) comes at a critical time in terms of innovations and exciting areas of science, but particularly in the areas linking environmental research and action. The most recent climate change Conference of the Parties meeting (COP), in Doha in December 2012, has now come and gone. As has been dissected in the press, very little was accomplished. Some will see this as a failure, as I do, and others will reasonably enough note that this meeting, the 18th such COP was1 never intended to be a milestone moment. The current plan, in fact, is for a 'post-Kyoto' international climate agreement to be adopted only at the COP20 summit in December 2015. As we lead up to COP20, and potentially other regional or national approaches to climate protection, innovations in science, innovations in policy tools, and political commitment must come together. The science of climate change only continues to get clearer and clearer, and bleaker [1]. Later this year the IPCC will release its Fifth Assessment Report, AR5. The draft versions are out for review now. ERL has published a number of papers on climate change science, mitigation and adaptation, but one area where the world needs a particular focus is on the nexus of science and action. A summary of the Intergovernmental Panel on Climate Change's findings from the first assessment report (FAR; 1990) to the latest report is presented in figure 1. This graphic is specifically not about the scientific record alone. What is most important about this figure is the juxtaposition of the language of science and the language of ... language. Figure 1. Figure 1. A superposition of the state of climate science in three key data sets, and the dates of the first, second, third and fourth assessment reports (FAR, SAR, TAR, and AR4, respectively) plotted as vertical lines. On the right are the key statements from each of these reports, along with the conclusion of the Special Report on Renewable Energy (SRREN, completed in 2011) which found that up to an 80% decarbonization of the global economy was possible if we can enable and launch a large-scale transition to a clean energy system consistent with what a number of 'leading edge' cities, regions, and nations have already accomplished or started. Note, in particular, that as the physical climate change metrics have progressed, the words—shown on the right—have also progressed. In 1990, at the time of the FAR the strongest scientific consensus statement was that another decade of data would likely be needed to clearly observe climate change. Through the second to fourth (SAR, TAR, and AR4) reports, increasing clarity on the science of climate change translated into a consensus of overwhelming blame on human activities. The key statements from each report are not only about the growing evidence for anthropogenically driven climate change, but they have moved into the ecological and social impacts of this change. AR4 critically concluded that climate change would lead to climate injustice as the poor, globally, bear the brunt of the impacts. Despite this 'Rosetta Stone' translating science to language, we have failed to act collectively. One area where ERL can advance the overall conversation is on this science/action interface. As AR5 emerges, the climate change/climate response interface will need deep, substantive, action that responds rapidly to new ideas and opportunities. The rapid publication and open access features of ERL are particularly critical here as events a such as Hurricane Sandy, economic or political advances in climate response made by cities, regions or nations, all warrant assessment and response. This is one of many areas where ERL has been at the forefront of the conversation, through not only research letters, but also commentary-style Perspective pieces and the conversation that ERL's sister community website environmentalresearchweb can facilitate. This process of translating proposed solutions—innovations—between interest groups, has been in far too short supply recently. One promising example has been the science/action dialog between a leading climate research center and the World Bank [2]. 'The Earth system's responses to climate change appear to be non-linear', points out Potsdam Institute for Climate Impact Research (PIK) Director, John Schellnhuber. 'If we venture far beyond the 2° guardrail, towards the 4° line, the risk of crossing tipping points rises sharply. The only way to avoid this is to break the business-as-usual pattern of production and consumption'. This assessment came in a report on climate science commissioned by the World Bank. Dr Jim Yong Kim, president of the World Bank noted succinctly and critically that: '... most importantly, a 4 °C world is so different from the current one that it comes with high uncertainty and new risks that threaten our ability to anticipate and plan for future adaptation needs.' This statement warrants careful discussion. Not only is World Bank President Kim affirming the results of the PIK study, and by direct extension the IPCC (because the same authors at PIK are also central to the work of the IPCC), but he is clearly noting that while many climate analysts rightly talk about the need to not exceed a 2° temperature increase, the path the world is currently on, namely 4°-6° will be catastrophic. This may come as too soft a statement to many in the scientific community, but it opens the door to an increasingly detailed dialog between climate change science and agencies engaged in action. Where ERL and other outlets for this conversation can play a critical role is in the many dimensions of climate change and response. The story is far from one only at the global level. As http://climatehotmap.org and many other location specific assessments detail, the environmental change story is playing out in millions of critical cases. Each warrants reporting and action, as well as integration with assessments of current data gathering and 'big data' needs, and with wider socioeconomic questions of effective political, and policy response. Through that, dialog papers in ERL will be critically important to advancing not only climate science, but the interactive dialog between knowledge and action. References [1] Hansen J, Sato M and Ruedy R 2012 Perception of climate change Proc. Natl Acad. Sci. USA 109 E2415-23 [2] Potsdam Institute for Climate Impact 2013 Turn Down the Heat: Why a 4 °C Warmer World Must be Avoided (Washington, DC: The World Bank) 1 The Kyoto Protocol was adopted on 11 December 1997 in Kyoto, Japan, and entered into force on 16 February 2005. As of September 2011, 191 states have signed and ratified the protocol. The United States signed but did not ratify the Protocol and Canada withdrew from it in 2011.

Climatological Impact of Atmospheric River Based on NARCCAP and DRI-RCM Datasets

NASA Astrophysics Data System (ADS)

Mejia, J. F.; Perryman, N. M.

2012-12-01

This study evaluates spatial responses of extreme precipitation environments, typically associated with Atmospheric River events, using Regional Climate Model (RCM) output from NARCCAP dataset (50km grid size) and the Desert Research Institute-RCM simulations (36 and 12 km grid size). For this study, a pattern-detection algorithm was developed to characterize Atmospheric Rivers (ARs)-like features from climate models. Topological analysis of the enhanced elongated moisture flux (500-300hPa; daily means) cores is used to objectively characterize such AR features in two distinct groups: (i) zonal, north Pacific ARs, and (ii) subtropical ARs, also known as "Pineapple Express" events. We computed the climatological responses of the different RCMs upon these two AR groups, from which intricate differences among RCMs stand out. This study presents these climatological responses from historical and scenario driven simulations, as well as implications for precipitation extreme-value analyses.

Modeling barrier island response to sea-level rise in the Outer Banks, North Carolina

USGS Publications Warehouse

Moore, Laura J.; List, Jeffrey H.; Williams, S. Jeffress; Stolper, David

2007-01-01

An 8500-year Holocene simulation developed in GEOMBEST provides a possible scenario to explain the evolution of barrier coast between Rodanthe and Cape Hatteras, NC. Sensitivity analyses suggest that in the Outer Banks, the rate of sea-level rise is the most important factor in determining how barrier islands evolve. The Holocene simulation provides a basis for future simulations, which suggest that if sea level rises up to 0.88 m by AD 2100, as predicted by the highest estimates of the Intergovernmental Panel on Climate Change, the barrier in the study area may migrate on the order of 2.5 times more rapidly than at present. If sea level rises beyond IPCC predictions to reach 1.4–1.9 m above modern sea level by AD 2100, model results suggest that barrier islands in the Outer Banks may become vulnerable to threshold collapse, disintegrating during storm events, by the end of the next century. Consistent with sensitivity analyses, additional simulations indicate that anthropogenic activities, such as increasing the rate of sediment supply through beach nourishment, will only slightly affect barrier island migration rates and barrier island vulnerability to collapse.

Lack of prognostic significance of conventional peritoneal cytology in colorectal and gastric cancers: results of EVOCAPE 2 multicentre prospective study.

PubMed

Cotte, E; Peyrat, P; Piaton, E; Chapuis, F; Rivoire, M; Glehen, O; Arvieux, C; Mabrut, J-Y; Chipponi, J; Gilly, F-N

2013-07-01

In digestive cancers, the prognostic significance of intraperitoneal free cancer cells remains unclear (IPCC). The main objective of this study was to assess the prognostic significance of IPCC in colorectal and gastric adenocarcinoma. The secondary objectives were to evaluate the predictive significance of IPCC for the development of peritoneal carcinomatosis (PC) and to evaluate the prevalence of synchronous PC and IPCC. This was a prospective multicentre study. All patients undergoing surgery for a digestive tract cancer had peritoneal cytology taken. Patients with gastric and colorectal cancer with no residual tumour after surgery and no evidence of PC were followed-up for 2 years. The primary end point was overall survival. Between 2002 and 2007, 1364 patients were enrolled and 956 were followed-up over 2 years. Prevalence of IPCC was 5.7% in colon cancer, 0.6% in rectal cancer and 19.5% in gastric cancer. The overall 2-year survival rate for patients with IPCC was 34.7% versus 86.8% for patients with negative cytology (p<0.0001). By multivariate analysis, IPCC was not an independent prognostic factor. No relationship between cytology and recurrence was found. The presence of IPCC was not an independent prognostic and didn't add any additional prognostic information to the usual prognostic factors related to the tumour (pTNM and differentiation). Moreover the presence of IPCC detected with this method didn't appear to predict development of PC. Peritoneal cytology using conventional staining doesn't seem to be a useful tool for the staging of colorectal and gastric cancers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Racial/Ethnic Differences in Inpatient Palliative Care Consultation for Patients With Advanced Cancer.

PubMed

Sharma, Rashmi K; Cameron, Kenzie A; Chmiel, Joan S; Von Roenn, Jamie H; Szmuilowicz, Eytan; Prigerson, Holly G; Penedo, Frank J

2015-11-10

Inpatient palliative care consultation (IPCC) may help address barriers that limit the use of hospice and the receipt of symptom-focused care for racial/ethnic minorities, yet little is known about disparities in the rates of IPCC. We evaluated the association between race/ethnicity and rates of IPCC for patients with advanced cancer. Patients with metastatic cancer who were hospitalized between January 1, 2009, and December 31, 2010, at an urban academic medical center participated in the study. Patient-level multivariable logistic regression was used to evaluate the association between race/ethnicity and IPCC. A total of 6,288 patients (69% non-Hispanic white, 19% African American, and 6% Hispanic) were eligible. Of these patients, 16% of whites, 22% of African Americans, and 20% of Hispanics had an IPCC (overall P < .001). Compared with whites, African Americans had a greater likelihood of receiving an IPCC (odds ratio, 1.21; 95% CI, 1.01 to 1.44), even after adjusting for insurance, hospitalizations, marital status, and illness severity. Among patients who received an IPCC, African Americans had a higher median number of days from IPCC to death compared with whites (25 v 17 days; P = .006), and were more likely than Hispanics (59% v 41%; P = .006), but not whites, to be referred to hospice. Inpatient settings may neutralize some racial/ethnic differences in access to hospice and palliative care services; however, irrespective of race/ethnicity, rates of IPCC remain low and occur close to death. Additional research is needed to identify interventions to improve access to palliative care in the hospital for all patients with advanced cancer. © 2015 by American Society of Clinical Oncology.

Racial/Ethnic Differences in Inpatient Palliative Care Consultation for Patients With Advanced Cancer

PubMed Central

Sharma, Rashmi K.; Cameron, Kenzie A.; Chmiel, Joan S.; Von Roenn, Jamie H.; Szmuilowicz, Eytan; Prigerson, Holly G.; Penedo, Frank J.

2015-01-01

Purpose Inpatient palliative care consultation (IPCC) may help address barriers that limit the use of hospice and the receipt of symptom-focused care for racial/ethnic minorities, yet little is known about disparities in the rates of IPCC. We evaluated the association between race/ethnicity and rates of IPCC for patients with advanced cancer. Patients and Methods Patients with metastatic cancer who were hospitalized between January 1, 2009, and December 31, 2010, at an urban academic medical center participated in the study. Patient-level multivariable logistic regression was used to evaluate the association between race/ethnicity and IPCC. Results A total of 6,288 patients (69% non-Hispanic white, 19% African American, and 6% Hispanic) were eligible. Of these patients, 16% of whites, 22% of African Americans, and 20% of Hispanics had an IPCC (overall P < .001). Compared with whites, African Americans had a greater likelihood of receiving an IPCC (odds ratio, 1.21; 95% CI, 1.01 to 1.44), even after adjusting for insurance, hospitalizations, marital status, and illness severity. Among patients who received an IPCC, African Americans had a higher median number of days from IPCC to death compared with whites (25 v 17 days; P = .006), and were more likely than Hispanics (59% v 41%; P = .006), but not whites, to be referred to hospice. Conclusion Inpatient settings may neutralize some racial/ethnic differences in access to hospice and palliative care services; however, irrespective of race/ethnicity, rates of IPCC remain low and occur close to death. Additional research is needed to identify interventions to improve access to palliative care in the hospital for all patients with advanced cancer. PMID:26324373

Statistical downscaling of regional climate scenarios for the French Alps : Impacts on snow cover

NASA Astrophysics Data System (ADS)

Rousselot, M.; Durand, Y.; Giraud, G.; Mérindol, L.; Déqué, M.; Sanchez, E.; Pagé, C.; Hasan, A.

2010-12-01

Mountain areas are particularly vulnerable to climate change. Owing to the complexity of mountain terrain, climate research at scales relevant for impacts studies and decisive for stakeholders is challenging. A possible way to bridge the gap between these fine scales and those of the general circulation models (GCMs) consists of combining high-resolution simulations of Regional Climate Models (RCMs) to statistical downscaling methods. The present work is based on such an approach. It aims at investigating the impacts of climate change on snow cover in the French Alps for the periods 2021-2050 and 2071-2100 under several IPCC hypotheses. An analogue method based on high resolution atmospheric fields from various RCMs and climate reanalyses is used to simulate local climate scenarios. These scenarios, which provide meteorological parameters relevant for snowpack evolution, subsequently feed the CROCUS snow model. In these simulations, various sources of uncertainties are thus considered (several greenhouse gases emission scenarios and RCMs). Results are obtained for different regions of the French Alps at various altitudes. For all scenarios, temperature increase is relatively uniform over the Alps. This regional warming is larger than that generally modeled at the global scale (IPCC, 2007), and particularly strong in summer. Annual precipitation amounts seem to decrease, mainly as a result of decreasing precipitation trends in summer and fall. As a result of these climatic evolutions, there is a general decrease of the mean winter snow depth and seasonal snow duration for all massifs. Winter snow depths are particularly reduced in the Northern Alps. However, the impact on seasonal snow duration is more significant in the Southern and Extreme Southern Alps, since these regions are already characterized by small winter snow depths at low elevations. Reference : IPCC (2007a). Climate change 2007 : The physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. In : Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H.L. Miller (eds.). Cambridge University Press, Cambridge, UK and New York, NY, USA. This work is performed in the framework of the SCAMPEI ANR (French research project).

Simulation and prediction of equilibrium line altitude of glaciers in the eastern Tibetan plateau

NASA Astrophysics Data System (ADS)

Duan, Keqin

2017-04-01

As the third polar on the Earth, the Tibetan plateau holds more than 40,000 glaciers which have experienced a rapid retreat in recent decades. Glacier loss has increased concern for water resources around the Tibetan plateau. The variability of equilibrium line altitude (ELA) indicates expansion and wastage of glacier directly. Here we simulated the ELA variability in the eastern Tibetan Plateau based on a full surface energy and mass balance model. The simulation results are agreement with the observations. The ELAs have risen at a rate of 2-8m/a since 1970 throughout the eastern Plateau, especially in the Qilian Mountain and the southeastern Plateau where the ELAs have risen to or over the top altitude of glacier, indicating the glaciers are accelerating to melting over there. Two typical glacier, Xiaodongkemadi glacier in the center of the Plateau and Qiyi glacier in the Qilian Mountain, are chosen to simulate its future ELA variability in the scenarios of RCP2.6, RCP4.5 and RCP 8.5 given by IPCC. The results show the ELAs will arrive to its maximum in around 2040 in the scenario of RCP2.6, while the ELAs will be over the top altitude of glaciers in 2035-2045 in the scenarios of RCP4.5 and RCP8.5, suggesting the glaciers in the eastern plateau will be melting until the disappear of the glaciers.

Simulations of the Evolution of Vapor Ejected by the LCROSS Impact on the Moon

NASA Astrophysics Data System (ADS)

Hurley, D. M.; Killen, R. M.; Team, L.; Potter, A. E.

2009-12-01

We present simulations of the vapor plume evolution resulting from the LCROSS impact onto the Moon. The simulation employs the Monte Carlo technique to follow the trajectory of particles assuming a collisionless atmosphere from the time the particle reaches the collisionless regime until the particle is lost from the Moon. We use realistic topography and examine how different implementation of physics within the model affect the evolution of the vapor plume. We simulate Na, H2O, OH, H, O, and Ar. If observations from LAMP and ground-based observations of Na are successful (they are TBD at the time of writing the abstract), we present the observations and use the model to interpret them. LAMP is the Lyman Alpha Mapping Project onboard Lunar Reconnaissance Orbiter. After impact, LAMP will observe FUV spectra in search of H and Ar in the atmosphere. We propose to use the McMath-Pierce Main to observe the impact plume, which is scheduled to occur on October 9, 2009 at 11:30 UT (7:30 a.m. EDT, 4:30 a.m. PDT), +/- 30 minutes. The spectrum of the impact plume will be measured using the Stellar Spectrograph and the McMath-Pierce Main telescope. The spectral range will be chosen to observed sodium. The purpose of this observation is to calibrate the impact. We know the sodium content of the regolith. A measure of the extra sodium content in the impact plume will serve to calibrate the impact. We will observe the impact region with the East Auxillary Telescope in white light to estimate the amount of dust produced by the impact. Distribution of simulated Ar particles 2 hours after the LCROSS impact.

Physical investigation on silver-water nanofluid natural convection for an F-shaped cavity under the magnetic field effects

NASA Astrophysics Data System (ADS)

Yadollahi, A.; Khalesidoost, A.; Kasaeipoor, A.; Hatami, M.; Jing, D.

2017-08-01

The effects of a magnetic field on a free convection regime of silver-water nanofluid are investigated. The considered geometry is an F-shaped cavity under the influence of a constant magnetic field. The left vertical walls temperature is Th, while the middle and right walls are at a constant temperature Tc, and the other walls are insulated. A FORTRAN program is developed for the numerical simulation of the considered problem. The governing equations are solved using the FVM with the SIMPLE algorithm. The effect of important physical parameters such as the Rayleigh number, the Hartmann number, AR and φ on the problem are discussed in detail. We have concluded that the increase in the Hartmann number causes a decrease in vertical velocity and heat transfer. By increasing the Rayleigh number, the influence of the Hartmann number will be increased. An increase in the dimensional ratio of the cavity causes a decrease in the Nusselt number except in AR = 0.4. The AR has the maximum impact on the local Nusselt number, at the bottom of the hot wall. The effect of the dimensional ratio of the cavity on the Nusselt number is reversed on top of the wall. The maximum value of the Nusselt number is observed at AR = 0.4.

Continuously on-going hindcast simulations for impact applications

NASA Astrophysics Data System (ADS)

Anders, Ivonne; Geyer, Beate

2016-04-01

Observations for e.g. temperature, precipitation, radiation, or wind are often used as meteorological forcing for different impact models, like e.g. crop models, urban models, economic models and energy system models. To assess a climate signal, the time period covered by the observation is often too short, they have gaps in between, and are inhomogeneous over time, due to changes in the measurements itself or in the near surrounding. Thus output from global and regional climate models can close the gap and provide homogeneous and physically consistent time series of meteorological parameters. CORDEX evaluation runs performed for the IPCC-AR5 provide a good base for the regional scale. However, with respect to climate services, continuously on-going hindcast simulations are required for regularly updated applications. In this study two projects are presented where hindcast-simulations optimized for a region of interest are performed continuously. The hindcast simulation performed by HZG covering Europe includes the EURO-CORDEX domain with a wider extend to the north to cover the ice edge. The simulation under consideration of the coastDat-experiences is available for the period of 1979 - 2015, prolonged ongoing and fulfills the customer's needs with respect of output variables, levels, intervals and statistical measures. CoastDat - customers are dealing e.g. with naval architecture, renewable energies, offshore wind farming, shipping emissions, coastal flood risk and others. The evaluation of the hindcast is done for Europe by using the EVAL-tool of the CCLM community and by comparison with HYRAS - data for Germany and neighbouring countries. The Climate Research group at the national Austrian weather service, ZAMG, is focusing on high mountain regions and, especially on the Alps. The hindcast-simulation is forced by ERA-interim and optimized for the Alpine Region. One of the main tasks is to capture strong precipitation events which often occur during summer when low pressure systems develop over the Golf of Genoa, moving to the North-East. This leads to floods and landslide events in Austria, Czech Republic and Germany. Such events are not sufficiently represented in the CORDEX-evaluation runs. ZAMG use high quality gridded precipitation and temperature data for the Alpine Region (1-6km) to evaluate the model performance. Data is provided e.g. to hydrological modellers (high water, low water), but also to assess icing capability of infrastructure.

Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

NASA Astrophysics Data System (ADS)

Vavrus, S. J.

2012-12-01

Although impending Arctic climate change is widely recognized, a wild card in its expression is how extreme weather events in this region will respond to greenhouse warming. Intense polar cyclones represent one type of high-latitude phenomena falling into this category, including very deep synoptic-scale cyclones and mesoscale polar lows. These systems inflict damage through high winds, heavy precipitation, and wave action along coastlines, and their impact is expected to expand in the future, when reduced sea ice cover allows enhanced wave energy. The loss of a buffering ice pack could greatly increase the rate of coastal erosion, which has already been increasing in the Arctic. These and related threats may amplify if extreme Arctic cyclones become more frequent and/or intense in a warming climate with much more open water to fuel them. This possibility has merit on the basis of GCM experiments, which project that greenhouse forcing causes lower mean sea level pressure (SLP) in the Arctic and a strengthening of the deepest storms over boreal high latitudes. In this study, the latest Coupled Model Intercomparison Project (CMIP5) climate model output is used to investigate the following questions: (1) What are the spatial and seasonal characteristics of extreme Arctic cyclones? (2) How well do GCMs simulate these phenomena? (3) Are Arctic cyclones already showing the expected response to greenhouse warming in climate models? To address these questions, a retrospective analysis is conducted of the transient 20th century simulations among the CMIP5 GCMs (spanning years 1850-2005). The results demonstrate that GCMs are able to reasonably represent extreme Arctic cyclones and that the simulated characteristics do not depend significantly on model resolution. Consistent with observational evidence, climate models generate these storms primarily during winter and within the climatological Aleutian and Icelandic Low regions. Occasionally the cyclones remain very intense over the Arctic Ocean. The historical tendency in Arctic SLP varies considerably among the GCMs, but the intermodel average trend exhibits a lowering of mean-annual pressure over the Arctic during the past 150 years and an increase in extreme cyclones in the vicinity of the Aleutian and Icelandic Lows. However, only weak trends in extreme cyclones are simulated through 2005 over the Arctic Ocean, where simulations of future climate change produce the largest SLP falls.

Rarefaction Wave Eliminator Concepts For A Large Blast/Thermal Simulator.

DTIC Science & Technology

1985-02-01

hard copies of the pressure-time records. Final data process- ing was completed with the computer, printer , and plotter. Plots of pressure- time records...F ATTN: Prof 0. Zinke Fayetteville, AR 72701 Cdr, CRDC, AMCCOM ATTI: 4O-SPS-IL University of California PM=-J Lawrence Livermore Lab SOM-RSP-A ATTN

The Influences of the 2D Image-Based Augmented Reality and Virtual Reality on Student Learning

ERIC Educational Resources Information Center

Liou, Hsin-Hun; Yang, Stephen J. H.; Chen, Sherry Y.; Tarng, Wernhuar

2017-01-01

Virtual reality (VR) learning environments can provide students with concepts of the simulated phenomena, but users are not allowed to interact with real elements. Conversely, augmented reality (AR) learning environments blend real-world environments so AR could enhance the effects of computer simulation and promote students' realistic experience.…

Affordances and Limitations of Immersive Participatory Augmented Reality Simulations for Teaching and Learning

ERIC Educational Resources Information Center

Dunleavy, Matt; Dede, Chris; Mitchell, Rebecca

2009-01-01

The purpose of this study was to document how teachers and students describe and comprehend the ways in which participating in an augmented reality (AR) simulation aids or hinders teaching and learning. Like the multi-user virtual environment (MUVE) interface that underlies Internet games, AR is a good medium for immersive collaborative…

Fate of Glaciers in the Tibetan Plateau by 2100

NASA Astrophysics Data System (ADS)

Duan, K.

2017-12-01

As the third polar on the Earth, the Tibetan plateau holds more than 40,000 glaciers which have experienced a rapid retreat in recent decades. The variability of equilibrium line altitude (ELA) indicates expansion and wastage of glacier directly. Here we simulated the ELA variability in the Tibetan Plateau based on a full surface energy and mass balance model. The simulation results are agreement with the observations. The ELAs have risen at a rate of 2-8m/a since 1970 throughout the Plateau, especially in the eastern Plateau where the ELAs have risen to or over the top altitude of glacier, indicating the glaciers are accelerating to melting over there. Two glaciers, XD glacier in the center of the Plateau and Qiyi glacier in the Qilian Mountain, are chosen to simulate its future ELA variability in the scenarios of RCP2.6, RCP4.5 and RCP 8.5 given by IPCC. The results show the ELAs will arrive to its maximum in around 2040 in RCP2.6, while the ELAs will be over the top altitude of glaciers in 2035-2045 in RCP4.5 and RCP8.5, suggesting the glaciers in the eastern Plateau will be melting until the disappear of the glaciers by the end of 2100.

Statewide Groundwater Recharge Modeling in New Mexico

NASA Astrophysics Data System (ADS)

Xu, F.; Cadol, D.; Newton, B. T.; Phillips, F. M.

2017-12-01

It is crucial to understand the rate and distribution of groundwater recharge in New Mexico because it not only largely defines a limit for water availability in this semi-arid state, but also is the least understood aspect of the state's water budget. With the goal of estimating groundwater recharge statewide, we are developing the Evapotranspiration and Recharge Model (ETRM), which uses existing spatial datasets to model the daily soil water balance over the state at a resolution of 250 m cell. The input datasets includes PRISM precipitation data, MODIS Normalized Difference Vegetation Index (NDVI), NRCS soils data, state geology data and reference ET estimates produced by Gridded Atmospheric Data downscalinG and Evapotranspiration Tools (GADGET). The current estimated recharge presents diffuse recharge only, not focused recharge as in channels or playas. Direct recharge measurements are challenging and rare, therefore we estimate diffuse recharge using a water balance approach. The ETRM simulated runoff amount was compared with USGS gauged discharge in four selected ephemeral channels: Mogollon Creek, Zuni River, the Rio Puerco above Bernardo, and the Rio Puerco above Arroyo Chico. Result showed that focused recharge is important, and basin characteristics can be linked with watershed hydrological response. As the sparse instruments in NM provide limited help in improving estimation of focused recharge by linking basin characteristics, the Walnut Gulch Experimental Watershed, which is one of the most densely gauged and monitored semiarid rangeland watershed for hydrology research purpose, is now being modeled with ETRM. Higher spatial resolution of field data is expected to enable detailed comparison of model recharge results with measured transmission losses in ephemeral channels. The final ETRM product will establish an algorithm to estimate the groundwater recharge as a water budget component of the entire state of New Mexico. Reference ET estimated by GADGET suggests 10% - 22% increase by the end of this century under IPCC AR4 A2 emission scenario. ETRM will help water planning for the state to face drought brought by the climate change.

Ar-39-Ar-40 Ages of Euerites and the Thermal History of Asteroid 4-Vesta

NASA Technical Reports Server (NTRS)

Bogard, Donald D.; Garrison, Daniel H.

2002-01-01

Eucrite meteorites are igneous rocks that derive from a large asteroid, probably 4 Vesta. Prior studies have shown that after eucrites formed, most were subsequently metamorphosed to temperatures up to equal to or greater than 800 C, and much later many were brecciated and heated by large impacts into the parent body surface. The uncommon basaltic, unbrecciated eucrites also formed near the surface but presumably escaped later brecciation, whereas the cumulate eucrites formed at depth where metamorphism may have persisted for a considerable period. To further understand the complex HED parent body thermal history, we determined new Ar-39-Ar-40 ages for nine eucrites classified as basaltic but unbrecciated, six eucrites classified as cumulate, and several basaltic-brecciated eucrites. Relatively precise Ar-Ar ages of two cumulate eucrites (Moama and EET87520) and four unbrecciated eucrites give a tight cluster at 4.48 +/1 0.01 Gyr. Ar-Ar ages of six additional unbrecciated eucrites are consistent with this age, within their larger age uncertainties. In contrast, available literature data on Pb-Pb isochron ages of four cumulate eucrites and one unbrecciated eucrite vary over 4.4-4.515 Gyr, and Sm-147 - Nd-143 isochron ages of four cumulate and three unbrecciated eucrites vary over 4.41-4.55 Gyr. Similar Ar-Ar ages for cumulate and unbrecciated eucrites imply that cumulate eucrites do not have a younger formation age than basaltic eucrites, as previously proposed. Rather, we suggest that these cumulate and unbrecciated eucrites resided at depth where parent body temperatures were sufficiently high to cause the K-Ar and some other chronometers to remain open diffusion systems. From the strong clustering of Ar-Ar ages at approximately 4.48 Gyr, we propose that these meteorites were excavated from depth in a single large impact event approximately 4.48 Gyr ago, which quickly cooled the samples and started the K-Ar chronometer. A large (approximately 460 km) crater postulated to exist on Vesta may be the source of these eucrites and of many smaller asteroids thought to be spectrally or physically associated with Vesta. Some Pb-Pb and Sm-Nd ages of cumulate and unbrecciated eucrites are consistent with the 4.48 Gyr Ar-Ar age, and the few older Pb-Pb and Sm-Nd ages may reflect isotopic closure prior to the large cratering event. One cumulate eucrite gives an Ar-Ar age of 4.25 Gyr; three additional cumulate eucrites give Ar-Ar ages of 3.4-3.7 Gyr; and two unbrecciated eucrites give Ar-Ar ages of approximately 3.55 Gyr. We attribute these younger ages to later impact heating. In addition, we find Ar-Ar impact-reset ages of several brecciated eucrites and eucritic clasts in howardites to fall in the range of 3.5-4.1 Gyr. Among these, Piplia Kalan, the first eucrite to show evidence for extinct 26 Al, was strongly impact heated approximately3.5 Gyr ago. When these data are combined with eucrite Ar-Ar ages in the literature, they confirm the previous suggestion that several large impact heating events occurred on Vesta over the time period approximately 4.1-3.4 Gyr ago. The onset of major impact heating may have occurred at similar times for both Vesta and the Moon, but impact heating appears to have persisted to a somewhat later time on Vesta compared to the Moon.

Autoregressive model in the Lp norm space for EEG analysis.

PubMed

Li, Peiyang; Wang, Xurui; Li, Fali; Zhang, Rui; Ma, Teng; Peng, Yueheng; Lei, Xu; Tian, Yin; Guo, Daqing; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2015-01-30

The autoregressive (AR) model is widely used in electroencephalogram (EEG) analyses such as waveform fitting, spectrum estimation, and system identification. In real applications, EEGs are inevitably contaminated with unexpected outlier artifacts, and this must be overcome. However, most of the current AR models are based on the L2 norm structure, which exaggerates the outlier effect due to the square property of the L2 norm. In this paper, a novel AR object function is constructed in the Lp (p≤1) norm space with the aim to compress the outlier effects on EEG analysis, and a fast iteration procedure is developed to solve this new AR model. The quantitative evaluation using simulated EEGs with outliers proves that the proposed Lp (p≤1) AR can estimate the AR parameters more robustly than the Yule-Walker, Burg and LS methods, under various simulated outlier conditions. The actual application to the resting EEG recording with ocular artifacts also demonstrates that Lp (p≤1) AR can effectively address the outliers and recover a resting EEG power spectrum that is more consistent with its physiological basis. Copyright © 2014 Elsevier B.V. All rights reserved.

Estimating Regional and National-Scale Greenhouse Gas Emissions in the Agriculture, Forestry, and Other Land Use (AFOLU) Sector using the `Agricultural and Land Use (ALU) Tool'

NASA Astrophysics Data System (ADS)

Spencer, S.; Ogle, S. M.; Wirth, T. C.; Sivakami, G.

2016-12-01

The Intergovernmental Panel on Climate Change (IPCC) provides methods and guidance for estimating anthropogenic greenhouse gas emissions for reporting to the United Nations Framework Convention on Climate Change. The methods are comprehensive and require extensive data compilation, management, aggregation, documentation and calculations of source and sink categories to achieve robust emissions estimates. IPCC Guidelines describe three estimation tiers that require increasing levels of country-specific data and method complexity. Use of higher tiers should improve overall accuracy and reduce uncertainty in estimates. The AFOLU sector represents a complex set of methods for estimating greenhouse gas emissions and carbon sinks. Major AFOLU emissions and sinks include carbon dioxide (CO2) from carbon stock change in biomass, dead organic matter and soils, urea or lime application to soils, and oxidation of carbon in drained organic soils; nitrous oxide (N2O) and methane (CH4) emissions from livestock management and biomass burning; N2O from organic amendments and fertilizer application to soils, and CH4 emissions from rice cultivation. To assist inventory compilers with calculating AFOLU-sector estimates, the Agriculture and Land Use Greenhouse Gas Inventory Tool (ALU) was designed to implement Tier 1 and 2 methods using IPCC Good Practice Guidance. It guides the compiler through activity data entry, emission factor assignment, and emissions calculations while carefully maintaining data integrity. ALU also provides IPCC defaults and can estimate uncertainty. ALU was designed to simplify the AFOLU inventory compilation process at regional or national scales, disaggregating the process into a series of steps reduces the potential for errors in the compilation process. An example application has been developed using ALU to estimate methane emissions from rice production in the United States.

Methane emissions from a landfill in north-east India: Performance of various landfill gas emission models.

PubMed

Gollapalli, Muralidhar; Kota, Sri Harsha

2018-03-01

Rapid urbanization and economic growth has led to significant increase in municipal solid waste generation in India during the last few decades and its management has become a major issue because of poor waste management practices. Solid waste generated is deposited into open dumping sites with hardly any segregation and processing. Carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) are the major greenhouse gases that are released from the landfill sites due to the biodegradation of organic matter. In this present study, CH 4 and CO 2 emissions from a landfill in north-east India are estimated using a flux chamber during September, 2015 to August, 2016. The average emission rates of CH 4 and CO 2 are 68 and 92 mg/min/m 2 , respectively. The emissions are highest in the summer whilst being lowest in winter. The diurnal variation of emissions indicated that the emissions follow a trend similar to temperature in all the seasons. Correlation coefficients of CH 4 and temperature in summer, monsoon and winter are 0.99, 0.87 and 0.97, respectively. The measured CH 4 in this study is in the range of other studies around the world. Modified Triangular Method (MTM), IPCC model and the USEPA Landfill gas emissions model (LandGEM) were used to predict the CH 4 emissions during the study year. The consequent simulation results indicate that the MTM, LandGEM-Clean Air Act, LandGEM-Inventory and IPCC models predict 1.9, 3.3, 1.6 and 1.4 times of the measured CH 4 emission flux in this study. Assuming that this higher prediction of CH 4 levels observed in this study holds well for other landfills in this region, a new CH 4 emission inventory (Units: Tonnes/year), with a resolution of 0.1 0  × 0.1 0 has been developed. This study stresses the importance of biodegradable composition of waste and meteorology, and also points out the drawbacks of the widely used landfill emission models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inhibition of beta-adrenergic receptor trafficking in adult cardiocytes by MAP4 decoration of microtubules.

PubMed

Cheng, Guangmao; Qiao, Fei; Gallien, Thomas N; Kuppuswamy, Dhandapani; Cooper, George

2005-03-01

Decreased beta-adrenergic receptor (beta-AR) number occurs both in animal models of cardiac hypertrophy and failure and in patients. beta-AR recycling is an important mechanism for the beta-AR resensitization that maintains a normal complement of cell surface beta-ARs. We have shown that 1) in severe pressure overload cardiac hypertrophy, there is extensive microtubule-associated protein 4 (MAP4) decoration of a dense microtubule network; and 2) MAP4 microtubule decoration inhibits muscarinic acetylcholine receptor recycling in neuroblastoma cells. We asked here whether MAP4 microtubule decoration inhibits beta-AR recycling in adult cardiocytes. [(3)H]CGP-12177 was used as a beta-AR ligand, and feline cardiocytes were isolated and infected with adenovirus containing MAP4 (AdMAP4) or beta-galactosidase (Adbeta-gal) cDNA. MAP4 decorated the microtubules extensively only in AdMAP4 cardiocytes. beta-AR agonist exposure reduced cell surface beta-AR number comparably in AdMAP4 and Adbeta-gal cardiocytes; however, after agonist withdrawal, the cell surface beta-AR number recovered to 78.4 +/- 2.9% of the pretreatment value in Adbeta-gal cardiocytes but only to 56.8 +/- 1.4% in AdMAP4 cardiocytes (P < 0.01). This result was confirmed in cardiocytes isolated from transgenic mice having cardiac-restricted MAP4 overexpression. In functional terms of cAMP generation, beta-AR agonist responsiveness of AdMAP4 cells was 47% less than that of Adbeta-gal cells. We conclude that MAP4 microtubule decoration interferes with beta-AR recycling and that this may be one mechanism for beta-AR downregulation in heart failure.

ID4 promotes AR expression and blocks tumorigenicity of PC3 prostate cancer cells.

PubMed

Komaragiri, Shravan Kumar; Bostanthirige, Dhanushka H; Morton, Derrick J; Patel, Divya; Joshi, Jugal; Upadhyay, Sunil; Chaudhary, Jaideep

2016-09-09

Deregulation of tumor suppressor genes is associated with tumorigenesis and the development of cancer. In prostate cancer, ID4 is epigenetically silenced and acts as a tumor suppressor. In normal prostate epithelial cells, ID4 collaborates with androgen receptor (AR) and p53 to exert its tumor suppressor activity. Previous studies have shown that ID4 promotes tumor suppressive function of AR whereas loss of ID4 results in tumor promoter activity of AR. Previous study from our lab showed that ectopic ID4 expression in DU145 attenuates proliferation and promotes AR expression suggesting that ID4 dependent AR activity is tumor suppressive. In this study, we examined the effect of ectopic expression of ID4 on highly malignant prostate cancer cell, PC3. Here we show that stable overexpression of ID4 in PC3 cells leads to increased apoptosis and decreased cell proliferation and migration. In addition, in vivo studies showed a decrease in tumor size and volume of ID4 overexpressing PC3 cells, in nude mice. At the molecular level, these changes were associated with increased androgen receptor (AR), p21, and AR dependent FKBP51 expression. At the mechanistic level, ID4 may regulate the expression or function of AR through specific but yet unknown AR co-regulators that may determine the final outcome of AR function. Copyright © 2016 Elsevier Inc. All rights reserved.

Temporary refugia for coral reefs in a warming world

NASA Astrophysics Data System (ADS)

van Hooidonk, R.; Maynard, J. A.; Planes, S.

2013-05-01

Climate-change impacts on coral reefs are expected to include temperature-induced spatially extensive bleaching events. Bleaching causes mortality when temperature stress persists but exposure to bleaching conditions is not expected to be spatially uniform at the regional or global scale. Here we show the first maps of global projections of bleaching conditions based on ensembles of IPCC AR5 (ref. ) models forced with the new Representative Concentration Pathways (RCPs). For the three RCPs with larger CO2 emissions (RCP 4.5, 6.0 and 8.5) the onset of annual bleaching conditions is associated with ~ 510ppm CO2 equivalent; the median year of all locations is 2040 for the fossil-fuel aggressive RCP 8.5. Spatial patterns in the onset of annual bleaching conditions are similar for each of the RCPs. For RCP 8.5, 26% of reef cells are projected to experience annual bleaching conditions more than 5 years later than the median. Some of these temporary refugia include the western Indian Ocean, Thailand, the southern Great Barrier Reef and central French Polynesia. A reduction in the growth of greenhouse-gas emissions corresponding to the difference between RCP 8.5 and 6.0 delays annual bleaching in ~ 23% of reef cells more than two decades, which might conceivably increase the potential for these reefs to cope with these changes.

Kinetic restriction of simple gases in porous carbons: transition-state theory study.

PubMed

Nguyen, Thanh X; Bhatia, Suresh K

2008-01-01

The separation of simple gases such as N2, Ar, CO2, and CH4 is an industrially important problem, particularly for the mitigation of greenhouse emissions. Furthermore, these gases are widely accepted as standard probing gases for the characterization of the microstructure of porous solids. However, a consistent set of microstructural parameters of a microporous solid determined from the use of adsorption measurements of these different gases is not always achieved because of differences in their pore accessibility. This is a long-standing and poorly understood problem. Here, we present the calculated results of the crossing time of N2, Ar, CO2, and CH4 between two neighboring cages through a constricted window in a realistic structural model of saccharose char, generated from hybrid reverse Monte Carlo (HRMC) simulation (Nguyen, T. X.; Bhatia, S. K.; Jain, S. K.; Gubbins, K. E. Mol. Simul. 2006, 32, 567-577) using transition state theory (TST), as described in our recent work (Nguyen, T. X.; Bhatia, S. K. J. Phys. Chem. 2007, 111, 2212-2222). The striking feature in these results is that whereas very fast diffusion of carbon dioxide within the temperature range of 273-343 K, with crossing time on the molecular dynamics scale (10-4-10-6 s), leads to instantaneous equilibrium and no hysteresis on the experimental time scale, slower diffusion of Ar and N2 at the low temperature of analysis indicates an accessibility problem. These results rationalize the experimental results of hysteresis for N2 at 77 K and Ar at 87 K but not for CO2 at 273 K in Takeda 3 A carbon molecular sieves. Furthermore, it is shown that CH4 diffusion through narrow pore mouths can be hindered even at ambient temperature. Finally, we show that the use of pore size and wall thickness distributions extracted from the adsorption of Ar at 87 K using the finite wall thickness (FWT) model (Nguyen, T. X.; Bhatia, S. K. Langmuir 2004, 20, 3532-3535 and Nguyen, T. X.; Bhatia, S. K. J. Phys. Chem. B 2004, 108, 14032-14042) provides the correct prediction of experimental CO2 adsorption in BPL and PCB carbons whereas that from N2 at 77 K gives a significant underprediction for both CO2 and CH4 in the BPL carbon. These trends are in excellent agreement with those predicted using the calculated crossing times.

Permafrost carbon-climate feedbacks accelerate global warming.

PubMed

Koven, Charles D; Ringeval, Bruno; Friedlingstein, Pierre; Ciais, Philippe; Cadule, Patricia; Khvorostyanov, Dmitry; Krinner, Gerhard; Tarnocai, Charles

2011-09-06

Permafrost soils contain enormous amounts of organic carbon, which could act as a positive feedback to global climate change due to enhanced respiration rates with warming. We have used a terrestrial ecosystem model that includes permafrost carbon dynamics, inhibition of respiration in frozen soil layers, vertical mixing of soil carbon from surface to permafrost layers, and CH(4) emissions from flooded areas, and which better matches new circumpolar inventories of soil carbon stocks, to explore the potential for carbon-climate feedbacks at high latitudes. Contrary to model results for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), when permafrost processes are included, terrestrial ecosystems north of 60°N could shift from being a sink to a source of CO(2) by the end of the 21st century when forced by a Special Report on Emissions Scenarios (SRES) A2 climate change scenario. Between 1860 and 2100, the model response to combined CO(2) fertilization and climate change changes from a sink of 68 Pg to a 27 + -7 Pg sink to 4 + -18 Pg source, depending on the processes and parameter values used. The integrated change in carbon due to climate change shifts from near zero, which is within the range of previous model estimates, to a climate-induced loss of carbon by ecosystems in the range of 25 + -3 to 85 + -16 Pg C, depending on processes included in the model, with a best estimate of a 62 + -7 Pg C loss. Methane emissions from high-latitude regions are calculated to increase from 34 Tg CH(4)/y to 41-70 Tg CH(4)/y, with increases due to CO(2) fertilization, permafrost thaw, and warming-induced increased CH(4) flux densities partially offset by a reduction in wetland extent.

76 FR 6651 - Intergovernmental Panel on Climate Change Special Report Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-07

... time that they accept the overall report. Principles and procedures for the IPCC and its preparation of..._documents/ipcc-principles-appendix-a.pdf (pdf) http://ipcc.ch/organization/organization_procedures.shtml In.... The following section of the report discusses risk management at the local, national and international...

Aerosol direct, indirect, semidirect, and surface albedo effects from sector contributions based on the IPCC AR5 emissions for preindustrial and present-day conditions

NASA Astrophysics Data System (ADS)

Bauer, Susanne E.; Menon, Surabi

2012-01-01

The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas-induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, with the hope that mitigation policies could be developed to target those emitters. Understanding the net effect of multisource emitting sectors and the involved cloud feedbacks is very challenging, and this paper will clarify forcing and feedback effects by separating direct, indirect, semidirect and surface albedo effects due to aerosols. To this end, we apply the Goddard Institute for Space Studies climate model including detailed aerosol microphysics to examine aerosol impacts on climate by isolating single emission sector contributions as given by the Coupled Model Intercomparison Project Phase 5 (CMIP5) emission data sets developed for Intergovernmental Panel on Climate Change (IPCC) AR5. For the modeled past 150 years, using the climate model and emissions from preindustrial times to present-day, the total global annual mean aerosol radiative forcing is -0.6 W/m2, with the largest contribution from the direct effect (-0.5 W/m2). Aerosol-induced changes on cloud cover often depends on cloud type and geographical region. The indirect (includes only the cloud albedo effect with -0.17 W/m2) and semidirect effects (-0.10 W/m2) can be isolated on a regional scale, and they often have opposing forcing effects, leading to overall small forcing effects on a global scale. Although the surface albedo effects from aerosols are small (0.016 W/m2), triggered feedbacks on top of the atmosphere (TOA) radiative forcing can be 10 times larger. Our results point out that each emission sector has varying impacts by geographical region. For example, the single sector most responsible for a net positive radiative forcing is the transportation sector in the United States, agricultural burning and transportation in Europe, and the domestic emission sector in Asia. These sectors are attractive mitigation targets.

Aerosol Direct, Indirect, Semidirect, and Surface Albedo Effects from Sector Contributions Based on the IPCC AR5 Emissions for Preindustrial and Present-day Conditions

NASA Technical Reports Server (NTRS)

Bauer, Susanne E.; Menon, Surabi

2012-01-01

The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas-induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, with the hope that mitigation policies could be developed to target those emitters. Understanding the net effect of multisource emitting sectors and the involved cloud feedbacks is very challenging, and this paper will clarify forcing and feedback effects by separating direct, indirect, semidirect and surface albedo effects due to aerosols. To this end, we apply the Goddard Institute for Space Studies climate model including detailed aerosol microphysics to examine aerosol impacts on climate by isolating single emission sector contributions as given by the Coupled Model Intercomparison Project Phase 5 (CMIP5) emission data sets developed for Intergovernmental Panel on Climate Change (IPCC) AR5. For the modeled past 150 years, using the climate model and emissions from preindustrial times to present-day, the total global annual mean aerosol radiative forcing is -0.6 W/m(exp 2), with the largest contribution from the direct effect (-0.5 W/m(exp 2)). Aerosol-induced changes on cloud cover often depends on cloud type and geographical region. The indirect (includes only the cloud albedo effect with -0.17 W/m(exp 2)) and semidirect effects (-0.10 W/m(exp 2)) can be isolated on a regional scale, and they often have opposing forcing effects, leading to overall small forcing effects on a global scale. Although the surface albedo effects from aerosols are small (0.016 W/m(exp 2)), triggered feedbacks on top of the atmosphere (TOA) radiative forcing can be 10 times larger. Our results point out that each emission sector has varying impacts by geographical region. For example, the single sector most responsible for a net positive radiative forcing is the transportation sector in the United States, agricultural burning and transportation in Europe, and the domestic emission sector in Asia. These sectors are attractive mitigation targets.

Development of a low-level 39Ar calibration standard – Analysis by absolute gas counting measurements augmented with simulation

DOE PAGES

Williams, Richard M.; Aalseth, C. E.; Brandenberger, J. M.; ...

2017-02-17

Here, this paper describes the generation of 39Ar, via reactor irradiation of potassium carbonate, followed by quantitative analysis (length-compensated proportional counting) to yield two calibration standards that are respectively 50 and 3 times atmospheric background levels. Measurements were performed in Pacific Northwest National Laboratory's shallow underground counting laboratory studying the effect of gas density on beta-transport; these results are compared with simulation. The total expanded uncertainty of the specific activity for the ~50 × 39Ar in P10 standard is 3.6% (k=2).

Development of a low-level 39Ar calibration standard – Analysis by absolute gas counting measurements augmented with simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Richard M.; Aalseth, C. E.; Brandenberger, J. M.

Here, this paper describes the generation of 39Ar, via reactor irradiation of potassium carbonate, followed by quantitative analysis (length-compensated proportional counting) to yield two calibration standards that are respectively 50 and 3 times atmospheric background levels. Measurements were performed in Pacific Northwest National Laboratory's shallow underground counting laboratory studying the effect of gas density on beta-transport; these results are compared with simulation. The total expanded uncertainty of the specific activity for the ~50 × 39Ar in P10 standard is 3.6% (k=2).

AR4VI: AR as an Accessibility Tool for People with Visual Impairments

PubMed Central

Coughlan, James M.; Miele, Joshua

2017-01-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness – an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well. PMID:29303163

AR4VI: AR as an Accessibility Tool for People with Visual Impairments.

PubMed

Coughlan, James M; Miele, Joshua

2017-10-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness - an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well.

Modeling and simulation studies of human β3 adrenergic receptor and its interactions with agonists.

PubMed

Sahi, Shakti; Tewatia, Parul; Malik, Balwant K

2012-12-01

β3 adrenergic receptor (β3AR) is known to mediate various pharmacological and physiological effects such as thermogenesis in brown adipocytes, lipolysis in white adipocytes, glucose homeostasis and intestinal smooth muscle relaxation. Several efforts have been made in this field to understand their function and regulation in different human tissues and they have emerged as potential attractive targets in drug discovery for the treatment of diabetes, depression, obesity etc. Although the crystal structures of Bovine Rhodopsin and β2 adrenergic receptor have been resolved, to date there is no three dimensional structural information on β3AR. Our aim in this study was to model 3D structure of β3AR by various molecular modeling and simulation techniques. In this paper, we describe a refined predicted model of β3AR using different algorithms for structure prediction. The structural refinement and minimization of the generated 3D model of β3AR were done by Schrodinger suite 9.1. Docking studies of β3AR model with the known agonists enabled us to identify specific residues, viz, Asp 117, Ser 208, Ser 209, Ser 212, Arg 315, Asn 332, within the β3AR binding pocket, which might play an important role in ligand binding. Receptor ligand interaction studies clearly indicated that these five residues showed strong hydrogen bonding interactions with the ligands. The results have been correlated with the experimental data available. The predicted ligand binding interactions and the simulation studies validate the methods used to predict the 3D-structure.

First Person Point of View Augmented Reality for Central Line Insertion Training: A Usability and Feasibility Study

PubMed Central

Rochlen, Lauryn R.; Levine, Robert; Tait, Alan R.

2016-01-01

Introduction The value of simulation in medical education and procedural skills training is well recognized. Despite this, many mannequin-based trainers are limited by the inability of the trainee to view the internal anatomical structures. This study evaluates the usability and feasibility of a 1st person point of view (POV) augmented reality (AR) trainer on needle insertion as a component of central venous catheter (CVC) placement. Methods Forty subjects, including medical students and anesthesiology residents and faculty participated. AR glasses were provided through which the relevant internal anatomical landmarks were projected. Following a practice period, participants were asked to place the needle in the mannequin without the benefit of the AR projected internal anatomy. The ability of the trainees to correctly place the needle was documented. Participants also completed a short survey describing their perceptions of the AR technology. Results Participants reported that the AR technology was realistic (77.5%) and that the ability to view the internal anatomy was helpful (92.5%). Furthermore, 85% and 82.1%, respectively, believed that the AR technology promoted learning and should be incorporated into medical training. The ability to successfully place the needle was similar between experienced and non-experienced participants, however, less experienced participants were more likely to inadvertently puncture the carotid artery. Conclusions Results of this pilot study demonstrated the usability and feasibility of AR technology as a potentially important adjunct to simulated medical skills training. Further development and evaluation of this innovative technology under a variety of simulated medical training settings would be an important next step. PMID:27930431

Ar-40/Ar-39 and U-Th-Pb dating of separated clasts from the Abee E4 chondrite

NASA Technical Reports Server (NTRS)

Bogard, D. D.; Unruh, D. M.; Tatsumoto, M.

1983-01-01

Ar-40/Ar-39 and U-Th-Pb are investigated for three clasts from the Abee (E4) enstatite chondrite, yielding Ar-40/Ar-39 plateau ages (and/or maximum ages) of 4.5 Gy, while two of the clasts give average ages of 4.4 Gy. The 4.4-4.5 Gy range does not resolve possible age differences among the clasts. The U-Th-Pb data are consistent with the interpretation that initial clast formation occurred 4.58 Gy ago, and that the clasts have since remained closed systems which have been contaminated with terrestrial Pb. The thermal history of Abee deduced from Ar data seems consistent with that deduced from magnetic data, suggesting that various Abee components experienced separate histories until brecciation no later than 4.4 Gy ago, experiencing no significant subsequent heating.

Computational Study on the Different Ligands Induced Conformation Change of β2 Adrenergic Receptor-Gs Protein Complex

PubMed Central

Bai, Qifeng; Zhang, Yang; Ban, Yihe; Liu, Huanxiang; Yao, Xiaojun

2013-01-01

β2 adrenergic receptor (β2AR) regulated many key physiological processes by activation of a heterotrimeric GTP binding protein (Gs protein). This process could be modulated by different types of ligands. But the details about this modulation process were still not depicted. Here, we performed molecular dynamics (MD) simulations on the structures of β2AR-Gs protein in complex with different types of ligands. The simulation results demonstrated that the agonist BI-167107 could form hydrogen bonds with Ser2035.42, Ser2075.46 and Asn2936.55 more than the inverse agonist ICI 118,551. The different binding modes of ligands further affected the conformation of β2AR. The energy landscape profiled the energy contour map of the stable and dissociated conformation of Gαs and Gβγ when different types of ligands bound to β2AR. It also showed the minimum energy pathway about the conformational change of Gαs and Gβγ along the reaction coordinates. By using interactive essential dynamics analysis, we found that Gαs and Gβγ domain of Gs protein had the tendency to separate when the inverse agonist ICI 118,551 bound to β2AR. The α5-helix had a relatively quick movement with respect to transmembrane segments of β2AR when the inverse agonist ICI 118,551 bound to β2AR. Besides, the analysis of the centroid distance of Gαs and Gβγ showed that the Gαs was separated from Gβγ during the MD simulations. Our results not only could provide details about the different types of ligands that induced conformational change of β2AR and Gs protein, but also supplied more information for different efficacies of drug design of β2AR. PMID:23922653

Mathematical modeling physiological effects of the overexpression of β2-adrenoceptors in mouse ventricular myocytes.

PubMed

Rozier, Kelvin; Bondarenko, Vladimir E

2018-03-01

Transgenic (TG) mice overexpressing β 2 -adrenergic receptors (β 2 -ARs) demonstrate enhanced myocardial function, which manifests in increased basal adenylyl cyclase activity, enhanced atrial contractility, and increased left ventricular function in vivo. To gain insights into the mechanisms of these effects, we developed a comprehensive mathematical model of the mouse ventricular myocyte overexpressing β 2 -ARs. We found that most of the β 2 -ARs are active in control conditions in TG mice. The simulations describe the dynamics of major signaling molecules in different subcellular compartments, increased basal adenylyl cyclase activity, modifications of action potential shape and duration, and the effects on L-type Ca 2+ current and intracellular Ca 2+ concentration ([Ca 2+ ] i ) transients upon stimulation of β 2 -ARs in control, after the application of pertussis toxin, upon stimulation with a specific β 2 -AR agonist zinterol, and upon stimulation with zinterol in the presence of pertussis toxin. The model also describes the effects of the β 2 -AR inverse agonist ICI-118,551 on adenylyl cyclase activity, action potential, and [Ca 2+ ] i transients. The simulation results were compared with experimental data obtained in ventricular myocytes from TG mice overexpressing β 2 -ARs and with simulation data on wild-type mice. In conclusion, a new comprehensive mathematical model was developed that describes multiple experimental data on TG mice overexpressing β 2 -ARs and can be used to test numerous hypotheses. As an example, using the developed model, we proved the hypothesis of the major contribution of L-type Ca 2+ current to the changes in the action potential and [Ca 2+ ] i transient upon stimulation of β 2 -ARs with zinterol. NEW & NOTEWORTHY We developed a new mathematical model for transgenic mouse ventricular myocytes overexpressing β 2 -adrenoceptors that describes the experimental findings in transgenic mice. The model reveals mechanisms of the differential effects of stimulation of β 2 -adrenoceptors in wild-type and transgenic mice overexpressing β 2 -adrenoceptors.

Vadose zone attenuation of organic compounds at a crude oil spill site - interactions between biogeochemical reactions and multicomponent gas transport.

PubMed

Molins, S; Mayer, K U; Amos, R T; Bekins, B A

2010-03-01

Contaminant attenuation processes in the vadose zone of a crude oil spill site near Bemidji, MN have been simulated with a reactive transport model that includes multicomponent gas transport, solute transport, and the most relevant biogeochemical reactions. Dissolution and volatilization of oil components, their aerobic and anaerobic degradation coupled with sequential electron acceptor consumption, ingress of atmospheric O(2), and the release of CH(4) and CO(2) from the smear zone generated by the floating oil were considered. The focus of the simulations was to assess the dynamics between biodegradation and gas transport processes in the vadose zone, to evaluate the rates and contributions of different electron accepting processes towards vadose zone natural attenuation, and to provide an estimate of the historical mass loss. Concentration distributions of reactive (O(2), CH(4), and CO(2)) and non-reactive (Ar and N(2)) gases served as key constraints for the model calibration. Simulation results confirm that as of 2007, the main degradation pathway can be attributed to methanogenic degradation of organic compounds in the smear zone and the vadose zone resulting in a contaminant plume dominated by high CH(4) concentrations. In accordance with field observations, zones of volatilization and CH(4) generation are correlated to slightly elevated total gas pressures and low partial pressures of N(2) and Ar, while zones of aerobic CH(4) oxidation are characterized by slightly reduced gas pressures and elevated concentrations of N(2) and Ar. Diffusion is the most significant transport mechanism for gases in the vadose zone; however, the simulations also indicate that, despite very small pressure gradients, advection contributes up to 15% towards the net flux of CH(4), and to a more limited extent to O(2) ingress. Model calibration strongly suggests that transfer of biogenically generated gases from the smear zone provides a major control on vadose zone gas distributions and vadose zone carbon balance. Overall, the model was successful in capturing the complex interactions between biogeochemical reactions and multicomponent gas transport processes. However, despite employing a process-based modeling approach, honoring observed parameter ranges, and generally obtaining good agreement between field observations and model simulations, accurate quantification of natural attenuation rates remains difficult. The modeling results are affected by uncertainties regarding gas phase saturations, tortuosities, and the magnitude of CH(4) and CO(2) flux from the smear zone. These findings highlight the need to better delineate gas fluxes at the model boundaries, which will help constrain contaminant degradation rates, and ultimately source zone longevity. Copyright 2009 Elsevier B.V. All rights reserved.

Vadose zone attenuation of organic compounds at a crude oil spill site - Interactions between biogeochemical reactions and multicomponent gas transport

USGS Publications Warehouse

Molins, S.; Mayer, K.U.; Amos, R.T.; Bekins, B.A.

2010-01-01

Contaminant attenuation processes in the vadose zone of a crude oil spill site near Bemidji, MN have been simulated with a reactive transport model that includes multicomponent gas transport, solute transport, and the most relevant biogeochemical reactions. Dissolution and volatilization of oil components, their aerobic and anaerobic degradation coupled with sequential electron acceptor consumption, ingress of atmospheric O2, and the release of CH4 and CO2 from the smear zone generated by the floating oil were considered. The focus of the simulations was to assess the dynamics between biodegradation and gas transport processes in the vadose zone, to evaluate the rates and contributions of different electron accepting processes towards vadose zone natural attenuation, and to provide an estimate of the historical mass loss. Concentration distributions of reactive (O2, CH4, and CO2) and non-reactive (Ar and N2) gases served as key constraints for the model calibration. Simulation results confirm that as of 2007, the main degradation pathway can be attributed to methanogenic degradation of organic compounds in the smear zone and the vadose zone resulting in a contaminant plume dominated by high CH4 concentrations. In accordance with field observations, zones of volatilization and CH4 generation are correlated to slightly elevated total gas pressures and low partial pressures of N2 and Ar, while zones of aerobic CH4 oxidation are characterized by slightly reduced gas pressures and elevated concentrations of N2 and Ar. Diffusion is the most significant transport mechanism for gases in the vadose zone; however, the simulations also indicate that, despite very small pressure gradients, advection contributes up to 15% towards the net flux of CH4, and to a more limited extent to O2 ingress. Model calibration strongly suggests that transfer of biogenically generated gases from the smear zone provides a major control on vadose zone gas distributions and vadose zone carbon balance. Overall, the model was successful in capturing the complex interactions between biogeochemical reactions and multicomponent gas transport processes. However, despite employing a process-based modeling approach, honoring observed parameter ranges, and generally obtaining good agreement between field observations and model simulations, accurate quantification of natural attenuation rates remains difficult. The modeling results are affected by uncertainties regarding gas phase saturations, tortuosities, and the magnitude of CH4 and CO2 flux from the smear zone. These findings highlight the need to better delineate gas fluxes at the model boundaries, which will help constrain contaminant degradation rates, and ultimately source zone longevity. ?? 2009 Elsevier B.V.

Climate sensitivity uncertainty: when is good news bad?

PubMed

Freeman, Mark C; Wagner, Gernot; Zeckhauser, Richard J

2015-11-28

Climate change is real and dangerous. Exactly how bad it will get, however, is uncertain. Uncertainty is particularly relevant for estimates of one of the key parameters: equilibrium climate sensitivity--how eventual temperatures will react as atmospheric carbon dioxide concentrations double. Despite significant advances in climate science and increased confidence in the accuracy of the range itself, the 'likely' range has been 1.5-4.5°C for over three decades. In 2007, the Intergovernmental Panel on Climate Change (IPCC) narrowed it to 2-4.5°C, only to reverse its decision in 2013, reinstating the prior range. In addition, the 2013 IPCC report removed prior mention of 3°C as the 'best estimate'. We interpret the implications of the 2013 IPCC decision to lower the bottom of the range and excise a best estimate. Intuitively, it might seem that a lower bottom would be good news. Here we ask: when might apparently good news about climate sensitivity in fact be bad news in the sense that it lowers societal well-being? The lowered bottom value also implies higher uncertainty about the temperature increase, definitely bad news. Under reasonable assumptions, both the lowering of the lower bound and the removal of the 'best estimate' may well be bad news. © 2015 The Author(s).

Challenges in global modeling of wetland extent and wetland methane dynamics

NASA Astrophysics Data System (ADS)

Spahni, R.; Melton, J. R.; Wania, R.; Stocker, B. D.; Zürcher, S.; Joos, F.

2012-12-01

Global wetlands are known to be climate sensitive, and are the largest natural emitters of methane (CH4). Increased wetland CH4 emissions could act as a positive feedback to future warming. Modelling of global wetland extent and wetland CH4 dynamics remains a challenge. Here we present results from the Wetland and Wetland CH4 Inter-comparison of Models Project (WETCHIMP) that investigated our present ability to simulate large scale wetland characteristics (e.g. wetland type, water table, carbon cycling, gas transport, etc.) and corresponding CH4 emissions. Ten models participated, covering the spectrum from simple to relatively complex, including models tailored either for regional or global simulations. The WETCHIMP experiments showed that while models disagree in spatial and temporal patterns of simulated CH4 emissions and wetland areal extent, they all do agree on a strong positive response to increased carbon dioxide concentrations. WETCHIMP made clear that we currently lack observation data sets that are adequate to evaluate model CH4 soil-atmosphere fluxes at a spatial scale comparable to model grid cells. Thus there are substantial parameter and structural uncertainties in large-scale CH4 emission models. As an illustration of the implications of CH4 emissions on climate we show results of the LPX-Bern model, as one of the models participating in WETCHIMP. LPX-Bern is forced with observed 20th century climate and climate output from an ensemble of five comprehensive climate models for a low and a high emission scenario till 2100 AD. In the high emission scenario increased substrate availability for methanogenesis due to a strong stimulation of net primary productivity, and faster soil turnover leads to an amplification of CH4 emissions with the sharpest increase in peatlands (+180% compared to present). Combined with prescribed anthropogenic CH4 emissions, simulated atmospheric CH4 concentration reaches ~4500 ppbv by 2100 AD, about 800 ppbv more than in standard IPCC scenarios. This represents a significant contribution to radiative forcing of global climate.

High resolution interpolation of climate scenarios for the conterminous USA and Alaska derived from general circulation model simulations

Treesearch

Linda A. Joyce; David T. Price; Daniel W. McKenney; R. Martin Siltanen; Pia Papadopol; Kevin Lawrence; David P. Coulson

2011-01-01

Projections of future climate were selected for four well-established general circulation models (GCM) forced by each of three greenhouse gas (GHG) emissions scenarios, namely A2, A1B, and B1 from the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES). Monthly data for the period 1961-2100 were downloaded mainly from the web...

ACK1/TNK2 Regulates Histone H4 Tyr88-phosphorylation and AR Gene Expression in Castration-Resistant Prostate Cancer.

PubMed

Mahajan, Kiran; Malla, Pavani; Lawrence, Harshani R; Chen, Zhihua; Kumar-Sinha, Chandan; Malik, Rohit; Shukla, Sudhanshu; Kim, Jongphil; Coppola, Domenico; Lawrence, Nicholas J; Mahajan, Nupam P

2017-06-12

The androgen receptor (AR) is critical for the progression of prostate cancer to a castration-resistant (CRPC) state. AR antagonists are ineffective due to their inability to repress the expression of AR or its splice variant, AR-V7. Here, we report that the tyrosine kinase ACK1 (TNK2) phosphorylates histone H4 at tyrosine 88 upstream of the AR transcription start site. The WDR5/MLL2 complex reads the H4-Y88-phosphorylation marks and deposits the transcriptionally activating H3K4-trimethyl marks promoting AR transcription. Reversal of the pY88-H4 epigenetic marks by the ACK1 inhibitor (R)-9bMS-sensitized naive and enzalutamide-resistant prostate cancer cells and reduced AR and AR-V7 levels to mitigate CRPC tumor growth. Thus, a feedforward ACK1/pY88-H4/WDR5/MLL2/AR epigenetic circuit drives CRPC and is necessary for maintenance of the malignant state. Copyright © 2017 Elsevier Inc. All rights reserved.

Modeling protein-small molecule interactions: structure and thermodynamics of noble gases binding in a cavity in mutant phage T4 lysozyme L99A.

PubMed

Mann, G; Hermans, J

2000-09-29

The complexes of phage T4 lysozyme L99A with noble gases have been studied by molecular dynamics simulation. In a long simulation of the complex with one Xe atom, the structure was found to undergo global conformation change involving a reversible opening and closing of the entrance to the substrate-binding site, during which the conformations of the N and C-terminal domains varied little. The distributions of Xe positions sampled in dynamics simulations were refined in terms of anisotropic Gaussian distributions via least-squares minimization of the difference between Fourier transforms. In addition, molecular transformation simulations have been applied in order to calculate the binding free energies of Xe, Kr and Ar relative to a standard state at a pressure of 1 bar. A single bound Xe is found to assume an equilibrium distribution over three adjacent preferred sites, while in a two-Xe complex, the two Xe atoms preferentially occupy two of these. The positions of the three sites agree closely with the positions of bound Xe determined in the refined crystal structure of a complex formed at a pressure of 8 bar Xe, and the calculated affinities agree well with the observed partial occupancies. At a pressure of 8 bar, a mixture of one-Xe and two-Xe complexes is present, and similarly for complexes with Kr and Ar, with single occupancy relatively more prevalent with Kr and Ar. (Binding of a third Xe atom is found to be quite unfavorable.) A comparison with simulation results for the binding of benzene to the same site leads to the conclusion that binding of Xe within cavities in proteins is common because of several favorable factors: (1) Xe has a large atomic polarizability; (2) Xe can be applied at a relatively high pressure, i.e. high chemical potential; (3) an unfavorable entropic term related to the need to orient the ligand in the binding site is absent. Finally, it is found that the model's binding energy of a water molecule in the cavity is insufficient to overcome the unfavorable binding entropy. Copyright 2000 Academic Press.

High Spatial Resolution Forecasting of Long-Term Monthly Precipitation and Mean Temperature Trends in Data Scarce Regions

NASA Astrophysics Data System (ADS)

Mosier, T. M.; Hill, D. F.; Sharp, K. V.

2013-12-01

High spatial resolution time-series data are critical for many hydrological and earth science studies. Multiple groups have developed historical and forecast datasets of high-resolution monthly time-series for regions of the world such as the United States (e.g. PRISM for hindcast data and MACA for long-term forecasts); however, analogous datasets have not been available for most data scarce regions. The current work fills this data need by producing and freely distributing hindcast and forecast time-series datasets of monthly precipitation and mean temperature for all global land surfaces, gridded at a 30 arc-second resolution. The hindcast data are constructed through a Delta downscaling method, using as inputs 0.5 degree monthly time-series and 30 arc-second climatology global weather datasets developed by Willmott & Matsuura and WorldClim, respectively. The forecast data are formulated using a similar downscaling method, but with an additional step to remove bias from the climate variable's probability distribution over each region of interest. The downscaling package is designed to be compatible with a number of general circulation models (GCM) (e.g. with GCMs developed for the IPCC AR4 report and CMIP5), and is presently implemented using time-series data from the NCAR CESM1 model in conjunction with 30 arc-second future decadal climatologies distributed by the Consultative Group on International Agricultural Research. The resulting downscaled datasets are 30 arc-second time-series forecasts of monthly precipitation and mean temperature available for all global land areas. As an example of these data, historical and forecast 30 arc-second monthly time-series from 1950 through 2070 are created and analyzed for the region encompassing Pakistan. For this case study, forecast datasets corresponding to the future representative concentration pathways 45 and 85 scenarios developed by the IPCC are presented and compared. This exercise highlights a range of potential meteorological trends for the Pakistan region and more broadly serves to demonstrate the utility of the presented 30 arc-second monthly precipitation and mean temperature datasets for use in data scarce regions.

Impacts of climate change in the sugarcane production in the center-south macro-region of Brazil

NASA Astrophysics Data System (ADS)

R Pereira, V.; Zullo, J., Jr.; Koga-Vicente, A.

2016-12-01

This paper describes the most important results of a Project developed over four years by a research network having 19 researchers and 45 students. The main objective of this Project was to generate alcohol production scenarios as support for the formulation of public policy applied to the adaptation of the Brazilian sugar and alcohol industry to the possible climate changes. The study area was the center-south macro-region of Brazil, with the states of São Paulo, Paraná, Minas Gerais, Mato Grosso do Sul and Goiás, that is the main producer area of sugarcane in the world. The scenarios were developed using the HadGEM2-ES and Miroc5 models of CMIP5/IPCC and did not show significant differences between them and were very close to those obtained with the HadCM3 and Miroc3 models of the AR4/IPCC. The results considering the sugarcane varieties grown nowadays indicate that in a scenario with changes in precipitation and temperatures, the main producing region will not have a decrease in municipalities with low climatic risk. Also the expansion region (South of Goiás and North-West of São Paulo) may become of high climatic risk, becoming an area where the artificial irrigation will be demanded. The challenge related to the water use and availability that already exists nowadays will be yet more important in the future. The expansion of Brazilian sugarcane production is being much more based on the territorial extension, i.e. by increasing the production area, than by increasing the productivity. The increased mechanization of cane harvesting improves the air quality and reduces the incidence of respiratory diseases. It is extremely important that incentives to mechanization be extended to other regions of the country since the end of burning benefits the health of people living close to the sugarcane fields. This confirms the need for planning this sector, with the development of new varieties and new production technologies considering the possible future climate conditions.

Comparison of the results of climate change impact assessment between RCP8.5 and SSP2 scenarios

NASA Astrophysics Data System (ADS)

Lee, D. K.; Park, J. H.; Park, C.; Kim, S.

2017-12-01

Climate change scenarios are mainly published by the Intergovernmental Panel on Climate Change (IPCC), and include SRES (Special Report on Emission Scenario) scenarios (IPCC Third Report), RCP (Representative Concentration Pathways) scenarios (IPCC 5th Report), and SSP (Shared Socioeconomic Pathways) scenarios. Currently widely used RCP scenarios are based on how future greenhouse gas concentrations will change. In contrast, SSP scenarios are that predict how climate change will change in response to socio-economic indicators such as population, economy, land use, and energy change. In this study, based on RCP 8.5 climate data, we developed a new Korean scenario using the future social and economic scenarios of SSP2. In the development of the scenario, not only Korea's emissions but also China and Japan's emissions were considered in terms of space. In addition, GHG emissions and air pollutant emissions were taken into consideration. Using the newly developed scenarios, the impacts assessments of the forest were evaluated and the impacts were evaluated using the RCP scenarios. The average precipitation is similar to the SSP2 scenario and the RCP8.5 scenario, but the SSP2 scenario shows the maximum value is lower than RCP8.5 scenario. This is because the SSP2 scenario simulates the summer precipitation weakly. The temperature distribution is similar for both scenarios, and it can be seen that the average temperature in the 2090s is higher than that in the 2050s. At present, forest net primary productivity of Korea is 693 tC/km2, and it is 679 tC/km2 when SSP2 scenario is applied. Also, the damage of forest by ozone is about 4.1-5.1%. On the other hand, when SSP2 scenario is applied, the forest net primary productivity of Korea is 607 tC/km2 and the forest net primary productivity of RCP8.5 scenario is 657 tC/km2. The analysis shows that the damage caused by climate change is reduced by 14.2% for the SSP2 scenario and 6.9% for the RCP8.5 scenario. The damage caused by ozone was about 5.0-5.6% in the SSP2 scenario and 3.8-4.2% in the RCP scenario.

Ar-39-Ar-40 Evidence for Early Impact Events on the LL Parent Body

NASA Technical Reports Server (NTRS)

Dixon, E. T.; Bogard, D. D.; Garrison, D. H.; Rubin, A. E.

2006-01-01

We determined Ar-39-Ar-40 ages of eight LL chondrites, and one igneous inclusion from an LL chondrite, with the object of understanding the thermal history of the LL-chondrite parent body. The meteorites in this study have a range of petrographic types from LL3.3 to LL6, and shock stages from S1 to S4. These meteorites reveal a range of K-Ar ages from 23.66 to 24.50 Ga, and peak ages from 23.74 to 24.55 Ga. Significantly, three of the eight chondrites (LL4, 5, 6) have K-Ar ages of -4.27 Ga. One of these (MIL99301) preserves an Ar-39-Ar-40 age of 4.23 +/- 0.03 Ga from low-temperature extractions, and an older age of 4.52 +/- 0.08 Ga from the highest temperature extractions. In addition, an igneous-textured impact melt DOM85505,22 has a peak Ar-39-Ar-40 age of >= 4.27 Ga. We interpret these results as evidence for impact events that occurred at about 4.27 Ga on the LL parent body that produced local impact melts, reset the Ar-39-Ar-40 ages of some meteorites, and exhumed (or interred) others, resulting in a range of cooling ages. The somewhat younger peak age of 3.74 Ga from GR095658 (LL3.3) suggests an additional impact event close to timing of impact-reset ages of some other ordinary chondrites between 3.6-3.8 Ga. The results from MIL99301 suggest that some apparently unshocked (Sl) chondrites may have substantially reset Ar-39-Ar-40 ages. A previous petrographic investigation of MIL99301 suggested that reheating to temperatures less than or equal to type 4 petrographic conditions (600C) caused fractures in olivine to anneal, resulting in a low apparent shock stage of S1 (unshocked). The Ar-39-Ar-40 age spectrum of MIL99301 is consistent with this interpretation. Older ages from high-T extractions may date an earlier impact event at 4.52 +/- 0.08 Ga, whereas younger ages from lower-T extractions date a later impact event at 4.23 Ar-39-Ar-40 0.03 Ga that may have caused annealing of feldspar and olivine

Screening and Characterization of Polygalacturonase as Potential Enzyme for Keprok Garut Orange (Citrus nobilis var. chrysocarpa) Juice Clarification

NASA Astrophysics Data System (ADS)

Widowati, E.; Utami, R.; Kalistyatika, K.

2017-11-01

Use of thermostable enzyme from bacilli for industrial application is significant. This research aimed to isolate thermophilic pectinolytic bacteria from orange peel and vegetable waste which produced thermostable polygalacturonase, to investigate the polygalacturonase ability in clarifying keprok Garut orange juice, and to characterize polygalacturonase based on pH optimum, temperature optimum, enzyme stability, enzyme kinetics KM, and Vmax. Obtained, 14 isolates that further selected to 4 best isolates based on highest polygalacturonase activity and keprok Garut orange juice clarification ability. Four selected enzyme isolates were AR 2, AR 4, KK 4, and KK 5 had ability to increase juice transmittance, decrease juice viscosity and also reduce total soluble solid. Furthermore 4 selected isolates were partially purified by ammonium sulphate precipitation and dialysis method. Four partially purified enzymes were known that enzyme character of AR 2 optimum at pH 6; AR 4 optimum at pH 5.5; KK 4 optimum at pH 6; and KK 5 optimum at pH 4.5. Four enzymes were optimum at temperature 60°C thus stable at temperature 50-60°C, this characteristic indicate that enzymes were thermostable. AR 2 showed active activity stable at pH 4-7; AR 4 showed active activity stable at pH 6-7; KK 4 showed active activity stable at pH 4-6; however KK 5 stable at pH 4-5. Enzyme AR 2 and KK 4 was getting inactive at pH 11, thus AR 4 and KK 5 inactive at pH 12. KM value of AR 2, AR 4, KK 4, and KK 5 was 0.0959; 0.0974; 0.0966; and 0.178 mg/ml respectively. Vmax of AR 2, AR 4, KK 4, and KK 5 was 0.0203; 0.0202; 0.0185; and 0.0229 U/ml respectively. Enzyme AR 2 was the most compatible enzyme to be applied in keprok Garut orange juice clarification for it had the lowest KM value.

Broadband anomalous reflection caused by unsymmetrical specific acoustic impedance in phononic crystals

NASA Astrophysics Data System (ADS)

Han, S. K.; Wu, C. W.; Chen, Z.

2018-01-01

We investigate through numerical simulation the anomalous reflection (AR) of acoustic waves with perfect phononic crystals (PCs). Broadband AR is observed in a wide angle for the oblique incidence. The AR is due to the unsymmetrical specific acoustic impedance (SAI) profile along the surface, which is caused by the high frequency incidence. The findings in this paper complement the theories for the AR of acoustic waves with PCs, and may find applications in acoustic engineerings.

Bubble formation, vesicularity and fractionation of noble gases during MORB degassing

NASA Astrophysics Data System (ADS)

Sator, N.; Guillot, B. B.; Aubry, G.

2012-12-01

The fractionation of noble gases in oceanic basalts gives information on the source region and on the transport of volatiles up to the seafloor. For instance, the large distribution (~1-1,000) of the 4He/40Ar* ratio in mid-ocean ridge basalts (MORB), is interpreted as the signature of different degassing scenarios taking place at depth. Thus, a low value of this ratio is explained by a closed system degassing whereas a high value is assigned either to an open system degassing (where vesicles are lost in a magma chamber or at depth during magma ascent) or to a kinetic disequilibrium induced by a rapid magma ascent just prior eruption. Unfortunately, CO2 has a very low solubility in basaltic melts at pressure corresponding to the seafloor and an overwhelming majority of erupted lavas have lost their pristine volatile contents. However notable exceptions are the popping rocks characterized by a large vesicularity, a high CO2 content and a 4He/40Ar* ratio compatible with the expected U/K ratio of the upper mantle. Those samples likely have experienced a CO2 exsolution at about 35 km depth in the oceanic mantle. So, the very existence of these exceptional MORB samples suggests that CO2-rich melts could be present at a greater depth. Thus, explosive eruptions near ocean spreading centers are well documented (Hekinian et al., 2000) and are associated with volcaniclastic deposits containing highly vesicular basalts, a feature which suggests that this volcanism is driven by CO2-rich magmas (Helo et al., 2011). But how much CO2-rich are these magmas, that is the question. The objective of this study is to use molecular dynamics simulation (MD) to evaluate the vesicularity and the fractionation of noble gases in a degassing MORB melt. A previous simulation study (Guillot and Sator, 2011) has shown that the solubility of CO2 in basaltic melts increases steadily with the pressure and deviates significantly from the Henry's law at high pressures. From the CO2 solubility curve and the equations of state of the two coexisting phases, deduced from the MD simulation, we have evaluated the evolution of the vesicularity of a MORB melt at depth as function of its initial CO2 contents. An excellent agreement is obtained between our results and data on MORB samples collected at oceanic ridges. A conclusion is that CO2-rich magmas may exist at 100 km depth or more in the oceanic mantle. Moreover, we have evaluated the partitioning and the fractionation of noble gases between the CO2-saturated melt and supercritical CO2 vesicles as function of the pressure. We show that the large distribution of the 4He/40Ar* ratio reported in the literature can be explained if the magma experiences a suite of vesiculation and vesicle loss during ascent. Finally, by applying a pressure drop to a volatile bearing melt (CO2+noble gas), the MD simulation reveals the main steps of bubble formation and noble gas transfer at the nanometric scale. A key result is that the transfer of noble gases is found to be concomitant with CO2 bubble nucleation, a finding which suggests that the difference in diffusivity between He and Ar in the degassing melt has practically no effect on the 4He/40Ar* ratio measured in the vesicles. Guillot B., Sator N. (2011), GCA 75, 1829-1857 Hekinian et al. (2000), J. Volcanol. Geotherm. Res. 98, 49-77 Helo et al. (2011), Nature Geoscience 4, 260-263

Clinical impact and cost-effectiveness of making third-line antiretroviral therapy available in sub-Saharan Africa: a model-based analysis in Côte d'Ivoire.

PubMed

Ouattara, Eric N; Ross, Eric L; Yazdanpanah, Yazdan; Wong, Angela Y; Robine, Marion; Losina, Elena; Moh, Raoul; Walensky, Rochelle P; Danel, Christine; Paltiel, A David; Eholié, Serge P; Freedberg, Kenneth A; Anglaret, Xavier

2014-07-01

In sub-Saharan Africa, HIV-infected adults who fail second-line antiretroviral therapy (ART) often do not have access to third-line ART. We examined the clinical impact and cost-effectiveness of making third-line ART available in Côte d'Ivoire. We used a simulation model to compare 4 strategies after second-line ART failure: continue second-line ART (C-ART2), continue second-line ART with an adherence reinforcement intervention (AR-ART2), immediate switch to third-line ART (IS-ART3), and continue second-line ART with adherence reinforcement, switching patients with persistent failure to third-line ART (AR-ART3). Third-line ART consisted of a boosted-darunavir plus raltegravir-based regimen. Primary outcomes were 10-year survival and lifetime incremental cost-effectiveness ratios (ICERs), in $/year of life saved (YLS). ICERs below $3585 (3 times the country per capita gross domestic product) were considered cost-effective. Ten-year survival was 6.0% with C-ART2, 17.0% with AR-ART2, 35.4% with IS-ART3, and 37.2% with AR-ART3. AR-ART2 was cost-effective ($1100/YLS). AR-ART3 had an ICER of $3600/YLS and became cost-effective if the cost of third-line ART decreased by <1%. IS-ART3 was less effective and more costly than AR-ART3. Results were robust to wide variations in the efficacy of third-line ART and of the adherence reinforcement, as well as in the cost of second-line ART. Access to third-line ART combined with an intense adherence reinforcement phase, used as a tool to distinguish between patients who can still benefit from their current second-line regimen and those who truly need third-line ART would provide substantial survival benefits. With minor decreases in drug costs, this strategy would be cost-effective.

Inactivation of ID4 promotes a CRPC phenotype with constitutive AR activation through FKBP52.

PubMed

Joshi, Jugal Bharat; Patel, Divya; Morton, Derrick J; Sharma, Pankaj; Zou, Jin; Hewa Bostanthirige, Dhanushka; Gorantla, Yamini; Nagappan, Peri; Komaragiri, Shravan Kumar; Sivils, Jeffrey C; Xie, Huan; Palaniappan, Ravi; Wang, Guangdi; Cox, Marc B; Chaudhary, Jaideep

2017-04-01

Castration-resistant prostate cancer (CRPC) is the emergence of prostate cancer cells that have adapted to the androgen-depleted environment of the prostate. In recent years, targeting multiple chaperones and co-chaperones (e.g., Hsp27, FKBP52) that promote androgen receptor (AR) signaling and/or novel AR regulatory mechanisms have emerged as promising alternative treatments for CRPC. We have shown that inactivation of inhibitor of differentiation 4 (ID4), a dominant-negative helix loop helix protein, promotes de novo steroidogenesis and CRPC with a gene expression signature that resembles constitutive AR activity in castrated mice. In this study, we investigated the underlying mechanism through which loss of ID4 potentiates AR signaling. Proteomic analysis between prostate cancer cell line LNCaP (L+ns) and LNCaP lacking ID4 (L(-)ID4) revealed elevated levels of Hsp27 and FKBP52, suggesting a role for these AR-associated co-chaperones in promoting constitutively active AR signaling in L(-)ID4 cells. Interestingly, protein interaction studies demonstrated a direct interaction between ID4 and the 52-kDa FK506-binding protein (FKBP52) in vitro, but not with AR. An increase in FKBP52-dependent AR transcriptional activity was observed in L(-)ID4 cells. Moreover, pharmacological inhibition of FKBP52-AR signaling, by treatment with MJC13, attenuated the tumor growth, weight, and volume in L(-)ID4 xenografts. Together, our results demonstrate that ID4 selectively regulates AR activity through direct interaction with FKBP52, and its loss, promotes CRPC through FKBP52-mediated AR signaling. © 2016 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.

A Tale of Two Earths: Reconciling the Lunar and Terrestrial Hadean Records

NASA Astrophysics Data System (ADS)

Boehnke, Patrick

Studying early Earth history is complicated by the fact that the rock record doesn't extend past 4 Ga and our only record for the Hadean (>4 Ga) comes to us from detrital zircons from the Jack Hills in Western Australia. The Hadean zircon record extends back to almost 4.4 Ga and has revealed that the early Earth may have had liquid water, a felsic crust, plate boundary interactions, and possibly a biosphere. On the other hand, analyses of lunar and meteoritic samples are used to argue for a hellish Hadean Earth where frequent, large impactors repeatedly destroyed the crust. Indeed, these two models stand in direct contradiction. The focus of this thesis is to examine the evidence for these two models and ultimately propose a reconciliation based on a new interpretation of the chronology of the lunar samples used to constrain the impact history into the early Earth-Moon system. In order to improve the understanding of zircon crystallization in igneous settings, we undertook experimental studies of zircon saturation which were analyzed using a novel ion imaging approach by a secondary ion mass spectrometer. This study confirmed the original model for zircon saturation, that it is a function of only temperature, melt composition, and Zr content. Indeed, the primary implication for the early Earth from this work is that zircons are much more likely to crystallize in a felsic rather than mafic magma and therefore simply the existence of Hadean zircons suggests a high likelihood for felsic Hadean magmatism. The majority of the thesis focuses on the interpretation of 40 Ar/39Ar ages of lunar and meteorite samples, specifically with regards to impact histories derived from compilations of such ages. The primary complication with lunar and meteorite 40Ar/ 39Ar ages is that the vast majority show evidence for later disturbances due to diffusive loss of 40Ar. To try and extract meaningful thermal histories from these samples, we undertook investigations of samples from Apollo 16 and the Jilin chondrite. We then used an extension of the multi-domain diffusion model that can model samples containing multiple activation energies (i.e., whole rock samples with multiple K bearing minerals) to propose that the 40Ar/39Ar system can be used to recover shock heating temperatures and durations. Having shown the effects of diffusive 40Ar loss on the accuracy of 40Ar/39Ar dating, we then explored the question as to whether or not compilations of disturbed 40Ar/ 39Ar ages simply misestimate the timing of bombardment episodes or are fundamentally inaccurate. For this we created a simple numerical model that simulates a chosen impact history on a surface and then creates a histogram of 40Ar/39Ar plateau ages. Our results show that rather than simply misestimate timing, compilations of 40Ar/ 39Ar ages can lead to inferences of illusory bombardment episodes. Finally, we examine the 40Ar/39Ar ages of suite of geochemically related Apollo 16 rocks to examine the effects of mixing and brecciation on the accuracy of inferred ages. By analyzing multiple rocks from each soil sample, we show that three out of six samples are not compatible with a single thermal history. That is to say, despite their close proximity during sampling and geochemical similarities, analyzed rocks in the soil sample have unique chronologies. Based on these findings, we developed a simple numerical model which shows that internal isochrons of mixed samples can yield erroneous ages while retaining a statistically acceptable mean squared weighted deviation (MSWD).

Refining the intraoperative measurement of the distal intrapancreatic part of a choledochal cyst during laparoscopic repair allows near total excision.

PubMed

Koga, Hiroyuki; Okawada, Manabu; Doi, Takashi; Miyano, Go; Lane, Geoffrey J; Yamataka, Atsuyuki

2015-10-01

During surgery for choledochal cyst (CC), any intrapancreatic CC (IPCC) must also be excised to prevent postoperative pancreatitis and stone formation. We report our technique for laparoscopic total IPCC excision (n = 16; mean age 6.0 years). We insert a fine ureteroscope with a light source into the opened CC through an extra 3.9-mm trocar placed in the epigastrium through a minute incision to identify the pancreatic duct orifice. By pulling the end of the ureteroscope emerging from the trocar gently to withdraw the tip from the pancreatic duct to where distal dissection was ceased under laparoscopic view, the IPCC can be measured. If longer than 5 mm, the distal CC is dissected further caudally until it is less than 5 mm. For accuracy, the distal CC is elevated with a suture that is exteriorized and clamped to provide constant traction. The IPCC was able to be measured in 11/16 (68 %). Initial lengths measured were 3-10 mm (5.2 ± 2.7 mm). Final IPCC were all 5 mm or less. Surgery was uncomplicated without any pancreatic duct injury and postoperative recovery was unremarkable. Follow-up MRI at 32 months showed no IPCC in any case. Measuring the IPCC enables total CC excision, thus reducing the potential for postoperative complications.

Downscaling of sea level and fluxes in the Malacca and Singapore Straits using A2 scenario projections of AR4 GCMs

NASA Astrophysics Data System (ADS)

Tkalich, Pavel; Koshebutsky, Volodymyr; Maderich, Vladimir; Thompson, Bijoy

2013-04-01

IPCC-coordinated work has been completed within Fourth Assessment Report (AR4) to project climate and ocean variables for the 21st century using coupled atmospheric-ocean General Circulation Models (GCMs). Resolution of the GCMs is not sufficient to resolve local features of narrow Malacca and Singapore Straits, having complex coastal line and bathymetry; therefore, dynamical downscaling of ocean variables from the global grid to the regional scale is advisable using ocean models, such as Regional Ocean Modeling System (ROMS). ROMS is customized for the domain centered on the Singapore and Malacca Straits, extending from 98°E to 109°E and 6°S to 14°N. Following IPCC methodology, the modelling is done for the past reference period 1961-1990, and then for the 21st century projections; subsequently, established past and projected trends and variability of ocean parameters are inter-compared. Boundary conditions for the past reference period are extracted from Simple Ocean Data Assimilation (SODA), while the projections are made using A2 scenario runs of ECHAM5 and CCSM3 GCMs. Atmospheric forcing for ROMS is downscaled with WRF using ERA-40 dataset for the past period, and outputs of atmospheric variables of respective GCMs for the projections. ROMS-downscaled regional sea level change during 1961-1990, corrected for the global thermosteric effect, land-ice melting and Global Isostatic Adjustment (GIA) effect, corresponds to a mean total trend of 1.52 mm/year, which is higher than the global estimate 1.25 mm/year and observed global sea-level rise (1.44 mm/year) for the same period. Local linear trend in the Singapore Strait (0.9 mm/year) corresponds to the observed trend at Victoria Dock tide gauge (1.1 mm/year) for the past period. Mean discharges through the Karimata, Malacca and Singapore Straits are 0.9, 0.21 and 0.12 Sv, respectively, fall in the range of observations and recent model estimates. A2 scenario projections using ROMS-ECHAM5 and ROMS-CCSM3 for 2011-2099 suggest that linear trends of sea level rise in Singapore Strait are 5.4 and 6.1 mm/year, respectively. These values fall in the range of global estimates of 3.0-8.5 mm/year. Mean sea level rise is expected around 0.43 m (ROMS-ECHAM5) and 0.47 m (ROMS-CCSM3) in 2099 relative to mean sea level in 2011. These values are greater than median estimation of global sea rise 0.32 under scenario A2. Mean discharge through Singapore Strait for scenario A2 during 2011 to 2099 is projected to be 0.062 Sv for ROMS-ECHAM5 and 0.11 Sv for ROMS-CCSM3. These projections are comparable to the discharges during 1961-1990 (0.065 and 0.11 Sv, respectively). The linear trend in discharges for the period 2011-2099 is relatively small with statistical confidence level being less than 95%. An important feature computationally discovered is the transient reversal of flow in the Singapore Strait during southwest monsoon. In general, the reversals of flow in ROMS-ECHAM5 and ROMS-CCSM3 are observed respectively to occur 1/3 and 1/5 of the whole period.

75 FR 3516 - Invitation for Recommendations for U.S. Authors and Reviewers to the Fifth Assessment Report of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-21

... Reviewers to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) ACTION... Intergovernmental Panel on Climate Change (IPCC). SUMMARY: The U.S. Department of State invites recommendations for... Intergovernmental Panel on Climate Change (IPCC), which will be developed and finalized over the coming four years...

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

NASA Astrophysics Data System (ADS)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

2017-05-01

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections at the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections atmore » the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.« less

A Combined Proteomic and Transcriptomic Analysis on Sulfur Metabolism Pathways of Arabidopsis thaliana under Simulated Acid Rain

PubMed Central

Wang, Wenhua; Simon, Martin; Wu, Feihua; Hu, Wenjun; Chen, Juan B.; Zheng, Hailei

2014-01-01

With rapid economic development, most regions in southern China have suffered acid rain (AR) pollution. In our study, we analyzed the changes in sulfur metabolism in Arabidopsis under simulated AR stress which provide one of the first case studies, in which the systematic responses in sulfur metabolism were characterized by high-throughput methods at different levels including proteomic, genomic and physiological approaches. Generally, we found that all of the processes related to sulfur metabolism responded to AR stress, including sulfur uptake, activation and also synthesis of sulfur-containing amino acid and other secondary metabolites. Finally, we provided a catalogue of the detected sulfur metabolic changes and reconstructed the coordinating network of their mutual influences. This study can help us to understand the mechanisms of plants to adapt to AR stress. PMID:24595051

Ar-Ar and I-Xe Ages and the Thermal History of IAB Meteorites

NASA Technical Reports Server (NTRS)

Bogard, Donald D.; Garrison, Daniel H.; Takeda, Hiroshi

2005-01-01

Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Na, Al and Ca, which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New Ar-39- Ar-40 ages for silicate from three different Caddo samples are consistent with a common age of 4.50-4.51 Gyr ago. Less well defined Ar-Ar degassing ages for inclusions from two other IABs, EET8333 and Udei Station, are approx.4.32 Gyr, whereas the age for Campo del Cielo varies considerably over approx.3.23-4.56 Gyr. New I-129-Xe-129 ages for Caddo County and EET8333 are 4557.9+/-0.1 Myr and 4557-4560 Myr, respectively, relative to an age of 4562.3 Myr for Shallowater. Considering all reported Ar-Ar degassing ages for IABs and related winonaites, the range is approx.4.32-4.53 Gyr, but several IABs give similar Ar ages of 4.50-4.52 Gyr. We interpret these older Ar ages to represent cooling after the time of last significant metamorphism on the parent body, and the younger ages to represent later 40Ar diffusion loss. The older Ar-Ar ages for IABs are similar to Sm-Nd and Rb-Sr isochron ages reported in the literature for Caddo County. Considering the possibility that IAB parent body formation was followed by impact disruption, reassembly, and metamorphism (e.g., Benedix et al. 2000), the Ar-Ar ages and IAB cooling rates deduced from Ni concentration profiles in IAB metal (Herpfer et al., 1994) are consistent if the time of the post-assembly metamorphism was as late as approx.4.53 Gyr ago. However, I-Xe ages reported for some IABs define much older ages of approx.4558-4566 Myr, which cannot easily be reconciled with the much younger Ar-Ar and Sm-Nd ages. An explanation for the difference in radiometric ages of IABs may reside in combinations of the following: a) I-Xe ages have very high closure temperatures and were not reset during metamorphism approx.4.53 Gyr ago; b) a bias exists in the 40K decay constants which makes these Ar-Ar ages approx.30 Myr too young; c) the reported Sm-Nd and Rb-Sr ages for Caddo are in error by amounts equal to or exceeding their reported 2-sigma uncertainties; and d) about 30 Myr after the initial heating that produced differentiation of Caddo silicate and mixing of silicate and metal, a mild metamorphism of the IAB parent body reset the Ar-Ar ages.

An MHD Simulation of Solar Active Region 11158 Driven with a Time-dependent Electric Field Determined from HMI Vector Magnetic Field Measurement Data

NASA Astrophysics Data System (ADS)

Hayashi, Keiji; Feng, Xueshang; Xiong, Ming; Jiang, Chaowei

2018-03-01

For realistic magnetohydrodynamics (MHD) simulation of the solar active region (AR), two types of capabilities are required. The first is the capability to calculate the bottom-boundary electric field vector, with which the observed magnetic field can be reconstructed through the induction equation. The second is a proper boundary treatment to limit the size of the sub-Alfvénic simulation region. We developed (1) a practical inversion method to yield the solar-surface electric field vector from the temporal evolution of the three components of magnetic field data maps, and (2) a characteristic-based free boundary treatment for the top and side sub-Alfvénic boundary surfaces. We simulate the temporal evolution of AR 11158 over 16 hr for testing, using Solar Dynamics Observatory/Helioseismic Magnetic Imager vector magnetic field observation data and our time-dependent three-dimensional MHD simulation with these two features. Despite several assumptions in calculating the electric field and compromises for mitigating computational difficulties at the very low beta regime, several features of the AR were reasonably retrieved, such as twisting field structures, energy accumulation comparable to an X-class flare, and sudden changes at the time of the X-flare. The present MHD model can be a first step toward more realistic modeling of AR in the future.

Radioactivities in returned lunar materials.

NASA Technical Reports Server (NTRS)

Fireman, E. L.; D'Amico, J.; Defelice, J.; Spannagel, G.

1972-01-01

The difference between the Ar-37 activities from similar locations in the rocks 12002 and 15555 provides direct measures of the Ar-37 activities produced by the 2 November 1969 flare. Differences between the Ar-37 activities in 14321 and 15555 give Ar-37 activities produced by the 24 January 1971 flare. The intensities of the two flares were determined by making use of measured Ar-37 cross sections in simulated lunar material. The depth dependence of tritium in samples and its temperature-release pattern provides information about the sources of the tritium and about the intensity of solar flares integrated over the past 30 years.

From California dreaming to California data: Challenging historic models for landfill CH4 emissions

USDA-ARS?s Scientific Manuscript database

Improved quantification of diverse CH4 sources at the urban scale is needed to guide local greenhouse gas (GHG) mitigation strategies in the Anthropocene. Herein, we focus on landfill CH4 emissions in California, challenging the current IPCC methodology which focuses on a climate dependency for land...

Slow-proton reemission from noble-gas solids

NASA Astrophysics Data System (ADS)

Mills, A. P., Jr.; Leventhal, M.; Lanzerotti, M. Y.; Zuckerman, D. M.; Gullikson, E. M.; Brandes, G. R.

1990-10-01

A 1-μsec pulsed proton beam is being used to study H+ thermalization and reemission from solid target surfaces in ultrahigh vacuum in order to help clarify analogous experiments using muon beams. Using a solid Ar target, vapor deposited on an ~=6-K Cu substrate, the reemission probability Y is 6×10-4 at a proton implantation energy E+H=1.4 keV and falls with increasing energy to 3×10-4 at E+H=5 keV and 2×10-4 at E+H=15 keV. Ne exhibits a 25% larger yield, while the yield for Kr is a factor of 4 lower. The reemitted protons are slow, with kinetic energies of order 1 eV. The reemitted proton yield Y decreases with an ~=100-m time constant, presumably due to deposition of neutral contaminants associated with the incoming beam, and thus ruling out the possibility that the slow protons originate from surface contaminants. For Ar, the observed variation of Y with E+H is interpreted with the help of a Monte Carlo calculation of the stopping and backscattering of the incident protons. The observed magnitude of Y is significantly greater than the calculated backscattering yield at the higher values of E+H. We therefore hypothesize that few-eV protons in the solid, which are considered ``stopped'' by the simulation, can diffuse a significant distance and escape into the vacuum. In our model, the diffusion length for few-eV protons in pristine solid Ar, λ0, is found to be λ0=(50+70-20) Å. However, the diffusion length we deduce from our measurements and simulations varies with E+H, possibly because of the interaction of the slow proton with its implantation trail. The vacancy density is computed to be too low for few-eV protons near the surface to be trapped at defects created by the energetic incoming particle. On the other hand, the proton neutralization probability could be dependent on the availability of free electrons in the ion trail of the implanted particle [O. E. Mogensen, J. Chem. Phys. 60, 998 (1974)]. Extension of our model to the case of positive muons suggests that an experiment to moderate 4-MeV μ+ with a solid Ar target [Harshman et al., Phys. Rev. B 36, 8850 (1987)] may have underestimated λ0 for μ+ due to sample impurities. It appears that the prospects for making a slow μ+ beam are better than we thought, but that remoderation of a few-keV μ+ beam using an Ar surface might have an efficiency less than 1% due to the high muonium-formation probability.

[The climate debate: the facts].

PubMed

van den Broeke, Michiel R

2009-01-01

The first report by the Intergovernmental Panel on Climate Change (IPCC) appeared almost 20 years ago. Environmental contamination has a negative effect on the environment in which we live. However, the public at large is confused about the ins and outs of climate change. Managers, politicians, various kinds of advisors, scientists, so-called experts, sceptics and journalists have all taken it upon themselves to lead the debate. Whose task is it to ensure a sound discussion? Surely it is the IPCC's task. However, most politicians and many journalists, and even many scientists, do not take the trouble to read the entire IPCC report or parts of it. As a consequence, much nonsense is published and broadcast. An effective procedure to deal with the climate problem starts with a fair discussion of the scientific evidence. My advice is: just read the free IPCC report: http://www.ipcc.ch/ and click on 'WG I The Physical Science Basis'.

Simple Climate Model Evaluation Using Impulse Response Tests

NASA Astrophysics Data System (ADS)

Schwarber, A.; Hartin, C.; Smith, S. J.

2017-12-01

Simple climate models (SCMs) are central tools used to incorporate climate responses into human-Earth system modeling. SCMs are computationally inexpensive, making them an ideal tool for a variety of analyses, including consideration of uncertainty. Despite their wide use, many SCMs lack rigorous testing of their fundamental responses to perturbations. Here, following recommendations of a recent National Academy of Sciences report, we compare several SCMs (Hector-deoclim, MAGICC 5.3, MAGICC 6.0, and the IPCC AR5 impulse response function) to diagnose model behavior and understand the fundamental system responses within each model. We conduct stylized perturbations (emissions and forcing/concentration) of three different chemical species: CO2, CH4, and BC. We find that all 4 models respond similarly in terms of overall shape, however, there are important differences in the timing and magnitude of the responses. For example, the response to a BC pulse differs over the first 20 years after the pulse among the models, a finding that is due to differences in model structure. Such perturbation experiments are difficult to conduct in complex models due to internal model noise, making a direct comparison with simple models challenging. We can, however, compare the simplified model response from a 4xCO2 step experiment to the same stylized experiment carried out by CMIP5 models, thereby testing the ability of SCMs to emulate complex model results. This work allows an assessment of how well current understanding of Earth system responses are incorporated into multi-model frameworks by way of simple climate models.

Understanding observed and simulated historical temperature trends in California

NASA Astrophysics Data System (ADS)

Bonfils, C. J.; Duffy, P. B.; Santer, B. D.; Lobell, D. B.; Wigley, T. M.

2006-12-01

In our study, we attempt 1) to improve our understanding of observed historical temperature trends and their underlying causes in the context of regional detection of climate change and 2) to identify possible neglected forcings and errors in the model response to imposed forcings at the origin of inconsistencies between models and observations. From eight different observational datasets, we estimate California-average temperature trends over 1950- 1999 and compare them to trends from a suite of IPCC control simulations of natural internal climate variability. We find that the substantial night-time warming occurring from January to September is inconsistent with model-based estimates of natural internal climate variability, and thus requires one or more external forcing agents to be explained. In contrast, we find that a significant day-time warming occurs only from January to March. Our confidence in these findings is increased because there is no evidence that the models systematically underestimate noise on interannual and decadal timescales. However, we also find that IPCC simulations of the 20th century that include combined anthropogenic and natural forcings are not able to reproduce such a pronounced seasonality of the trends. Our first hypothesis is that the warming of Californian winters over the second half of the twentieth century is associated with changes in large-scale atmospheric circulation that are likely to be human-induced. This circulation change is underestimated in the historical simulations, which may explain why the simulated warming of Californian winters is too weak. We also hypothesize that the lack of a detectable observed increase in summertime maximum temperature arises from a cooling associated with large-scale irrigation. This cooling may have, until now, counteracted the warming induced by increasing greenhouse gases and urbanization effects. Omitting to include this forcing in the simulations can result in overestimating the summertime maximum temperature trends. We conduct an empirical study based on observed climate and irrigation changes to evaluate this assumption.

Estimation of CO2 emissions from waste incinerators: Comparison of three methods.

PubMed

Lee, Hyeyoung; Yi, Seung-Muk; Holsen, Thomas M; Seo, Yong-Seok; Choi, Eunhwa

2018-03-01

Climate-relevant CO 2 emissions from waste incineration were compared using three methods: making use of CO 2 concentration data, converting O 2 concentration and waste characteristic data, and using a mass balance method following Intergovernmental Panel on Climate Change (IPCC) guidelines. For the first two methods, CO 2 and O 2 concentrations were measured continuously from 24 to 86 days. The O 2 conversion method in comparison to the direct CO 2 measurement method had a 4.8% mean difference in daily CO 2 emissions for four incinerators where analyzed waste composition data were available. However, the IPCC method had a higher difference of 13% relative to the direct CO 2 measurement method. For three incinerators using designed values for waste composition, the O 2 conversion and IPCC methods in comparison to the direct CO 2 measurement method had mean differences of 7.5% and 89%, respectively. Therefore, the use of O 2 concentration data measured for monitoring air pollutant emissions is an effective method for estimating CO 2 emissions resulting from waste incineration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells

PubMed Central

Bolton, Eric C.

2015-01-01

The androgen receptor (AR) mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT). However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR), and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK) complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation. PMID:26372468

Thermal thresholds as predictors of seed dormancy release and germination timing: altitude-related risks from climate warming for the wild grapevine Vitis vinifera subsp. sylvestris.

PubMed

Orrù, Martino; Mattana, Efisio; Pritchard, Hugh W; Bacchetta, Gianluigi

2012-12-01

The importance of thermal thresholds for predicting seed dormancy release and germination timing under the present climate conditions and simulated climate change scenarios was investigated. In particular, Vitis vinifera subsp. sylvestris was investigated in four Sardinian populations over the full altitudinal range of the species (from approx. 100 to 800 m a.s.l). Dried and fresh seeds from each population were incubated in the light at a range of temperatures (10-25 and 25/10 °C), without any pre-treatment and after a warm (3 months at 25 °C) or a cold (3 months at 5 °C) stratification. A thermal time approach was then applied to the germination results for dried seeds and the seed responses were modelled according to the present climate conditions and two simulated scenarios of the Intergovernmental Panel on Climate Change (IPCC): B1 (+1·8 °C) and A2 (+3·4 °C). Cold stratification released physiological dormancy, while very few seeds germinated without treatments or after warm stratification. Fresh, cold-stratified seeds germinated significantly better (>80 %) at temperatures ≥20 °C than at lower temperatures. A base temperature for germination (T(b)) of 9·0-11·3 °C and a thermal time requirement for 50 % of germination (θ(50)) ranging from 33·6 °Cd to 68·6 °Cd were identified for non-dormant cold-stratified seeds, depending on the populations. This complex combination of thermal requirements for dormancy release and germination allowed prediction of field emergence from March to May under the present climatic conditions for the investigated populations. The thermal thresholds for seed germination identified in this study (T(b) and θ(50)) explained the differences in seed germination detected among populations. Under the two simulated IPCC scenarios, an altitude-related risk from climate warming is identified, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window.

Hybrid Modeling of SiH4/Ar Discharge in a Pulse Modulated RF Capacitively Coupled Plasma

NASA Astrophysics Data System (ADS)

Xi-Feng, Wang; Yuan-Hong, Song; You-Nian, Wang; PSEG Team

2015-09-01

Pulsed plasmas have offered important advantages in future micro-devices, especially for electronegative gas plasmas. In this work, a one-dimensional fluid and Monte-Carlo (MC) hybrid model is developed to simulate SiH4/Ar discharge in a pulse modulated radio-frequency (RF) capacitively coupled plasma (CCP). Time evolution densities of different species, such as electrons, ions, radicals, are calculated, as well as the electron energy probability function (EEPF) which is obtained by a MC simulation. By pulsing the RF source, the electron energy distributions and plasma properties can be modulated by pulse frequency and duty cycle. High electron energy tails are obtained during power-on period, with the SiHx densities increasing rapidly mainly by SiH4 dissociation. As the RF power is off, the densities in the bulk region decrease rapidly owing to high energy electrons disappear, but increase near electrodes since diffusion without the confinement of high electric field, which can prolong the time of radials deposition on the plate. Especially, in the afterglow, the increase of negative ions near the electrodes results from cool electron attachment, which are good for film deposition. This work was supported by the National Natural Science Foundation of China (Grant No. 11275038).

Assessing Leader Cognitive Skills with Situational Judgment Tests: Construct Validity Results

DTIC Science & Technology

2010-09-01

M2A1, M2A3 , M2A4a, M2A4b, M2A4e, M2A4k .54** Factor 5 (5 items): Mission Statement M3Ba, M3Bb, M3Bc, M3Bd, M3Be .33** Factor 6 (11 items): Mission...Organization. Team A 2/A/4-99 AR ( M2A3 ) 3/A/4-99 AR ( M2A3 ) 1/C/4-99 AR (M1A2 SEP) TF Control Scout Platoon Mortar Platoon 1/A/2-244 CHEM...SMK) (DS) B/1st BSB (OPCON) Maintenance Platoon Team B 2/B/4-99 AR ( M2A3 ) 3/B/4-99 AR ( M2A3 ) 1/DC/4-99 AR (M1A2 SEP) Team C 1

The North American Forest Sector Outlook Study 2006-2030

Treesearch

Jeffrey P. Prestemon; Joseph Buongiorno

2012-01-01

Projections for the United States and Canada to 2030 have been made with a global model to account for concurrent changes in other countries. Three future scenarios were investigated: two IPCC-based scenarios assuming the rapid growth of wood-based energy, and one IPCC-based scenario without this assumption. The model, under the IPCC scenarios, accounted for trends in...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duane, Greg; Tsonis, Anastasios; Kocarev, Ljupco

This collaborative reserach has several components but the main idea is that when imperfect copies of a given nonlinear dynamical system are coupled, they may synchronize for some set of coupling parameters. This idea is to be tested for several IPCC-like models each one with its own formulation and representing an “imperfect” copy of the true climate system. By computing the coupling parameters, which will lead the models to a synchronized state, a consensus on climate change simulations may be achieved.

An Approximately 4.35 Ga Ar-Ar Age for GRA 8 and the Complex Chronology of its Parent Body

NASA Technical Reports Server (NTRS)

Park, J.; Nyquist, Laurence E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Reese, Y. D.

2010-01-01

GRA06128 and GRA06129 (hereafter GRA 8 and GRA 9) are partial melts of a parent body of approximately chondritic composition. We reported a conventional Sm-147-Nd-143 isochron age of 4.559+/-0.096 Ga and a 146 Sm-142Nd model age of 4.549+/-0.036 for combined data for the two rocks. Plagioclase plus whole rock and leachate (approx.phosphate) samples gave a secondary Sm-147-Nd-143 age of 3.4+/-0.4 Ga. An Ar-39-Ar-40 age of 4.460+/-0.028 Ga was interpreted as dating metamorphism in GRA 9. We report Ar-39-Ar-40 ages in the range approx.4344-4366 Ma for GRA 8, establishing similar but different Ar-39-Ar-40 ages for the two rocks, consistent with their different Sr-isotopic systematics, and discuss these ages in the context of the complex sequence of events that affected these samples.

An Approximately 4.35 Ga Ar-Ar Age for GRA 8 and the Complex Chronology of its Parent Body

NASA Technical Reports Server (NTRS)

Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Reese, Y. D.

2010-01-01

GRA06128 and GRA06129 (hereafter GRA 8 and GRA 9) are partial melts of a parent body of approximately chondritic composition. We reported a conventional SM-147Sm-ND_143 isochron age of 4.559 +/-.096 Ga and a SM-146-142Nd model age of 4.549 +/- 0.036 for combined data for the two rocks. Plagioclase plus whole rock and leachate (approximately phosphate) samples gave a secondary SM-147-ND-143 age of 3.4 +/-0.4 Ga. An Ar-39-Ar-40 age of 4.460+/-0.028 Ga was interpreted by as dating metamorphism in GRA 9. We report Ar-39-Ar-40 ages in the range approximately 4344-4366 Ma for GRA 8, establishing similar but different Ar-39-Ar-40 ages for the two rocks, consistent with their different Sr-istopic systematics, and discuss these ages in the context of the complex sequence of events that affected these samples

Changes in the frequency of extreme air pollution events over the Eastern United States and Europe

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Fiore, A. M.; Fang, Y.; Staehelin, J.

2011-12-01

Over the past few decades, thresholds for national air quality standards, intended to protect public health and welfare, have been lowered repeatedly. At the same time observations, over Europe and the Eastern U.S., demonstrate that extreme air pollution events (high O3 and PM2.5) are typically associated with stagnation events. Recent work showed that in a changing climate high air pollution events are likely to increase in frequency and duration. Within this work we examine meteorological and surface ozone observations from CASTNet over the U.S. and EMEP over Europe and "idealized" simulations with the GFDL AM3 chemistry-climate model, which isolate the role of climate change on air quality. Specifically, we examine an "idealized 1990s" simulation, forced with 20-year mean monthly climatologies for sea surface temperatures and sea ice from observations for 1981-2000, and an "idealized 2090s" simulation forced by the observed climatologies plus the multi-model mean changes in sea surface temperature and sea ice simulated by 19 IPCC AR-4 models under the A1B scenario for 2081-2100. With innovative statistical tools (empirical orthogonal functions (EOFs) and statistics of extremes (EVT)), we analyze the frequency distribution of past, present and future extreme air pollution events over the Eastern United States and Europe. The upper tail of observed values at individual stations (e.g., within the CASTNet), i.e., the extremes (maximum daily 8-hour average (MDA8) O3>60ppb) are poorly described by a Gaussian distribution. However, further analysis showed that applying Peak-Over-Threshold-models, better capture the extremes and allows us to estimate return levels of pollution events above certain threshold values of interest. We next apply EOF analysis to identify regions that vary coherently within the ground-based monitoring networks. Over the United States, the first EOF obtained from the model in both the 1990s and 2090s idealized simulations identifies the Northeast as a region that varies coherently. Correlation analysis reveals that this EOF pattern is most strongly expressed in association with high surface temperature and high surface pressure conditions, consistent with previous work showing that observed O3 episodes over this area reflect the combined impacts of stagnation and increased chemical production. Next steps include the extension of this analysis applying EVT tools to the principal component time series associated with this EOF. The combination of EOF and EVT tools applied to the GFDL AM3 1990s vs. 2090s idealized simulations will enable us to quantify changes in the return levels of air pollution extremes. Therefore the combination of observational data and numerical and statistical models should allow us to identify key driving forces between high air pollution events and to estimate changes in the frequency of such events under different climate change scenarios.

Outcome of ABCA4 disease-associated alleles in autosomal recessive retinal dystrophies: retrospective analysis in 420 Spanish families.

PubMed

Riveiro-Alvarez, Rosa; Lopez-Martinez, Miguel-Angel; Zernant, Jana; Aguirre-Lamban, Jana; Cantalapiedra, Diego; Avila-Fernandez, Almudena; Gimenez, Ascension; Lopez-Molina, Maria-Isabel; Garcia-Sandoval, Blanca; Blanco-Kelly, Fiona; Corton, Marta; Tatu, Sorina; Fernandez-San Jose, Patricia; Trujillo-Tiebas, Maria-Jose; Ramos, Carmen; Allikmets, Rando; Ayuso, Carmen

2013-11-01

To provide a comprehensive overview of all detected mutations in the ABCA4 gene in Spanish families with autosomal recessive retinal disorders, including Stargardt's disease (arSTGD), cone-rod dystrophy (arCRD), and retinitis pigmentosa (arRP), and to assess genotype-phenotype correlation and disease progression in 10 years by considering the type of variants and age at onset. Case series. A total of 420 unrelated Spanish families: 259 arSTGD, 86 arCRD, and 75 arRP. Spanish families were analyzed through a combination of ABCR400 genotyping microarray, denaturing high-performance liquid chromatography, and high-resolution melting scanning. Direct sequencing was used as a confirmation technique for the identified variants. Screening by multiple ligation probe analysis was used to detect possible large deletions or insertions in the ABCA4 gene. Selected families were analyzed further by next generation sequencing. DNA sequence variants, mutation detection rates, haplotypes, age at onset, central or peripheral vision loss, and night blindness. Overall, we detected 70.5% and 36.6% of all expected ABCA4 mutations in arSTGD and arCRD patient cohorts, respectively. In the fraction of the cohort where the ABCA4 gene was sequenced completely, the detection rates reached 73.6% for arSTGD and 66.7% for arCRD. However, the frequency of possibly pathogenic ABCA4 alleles in arRP families was only slightly higher than that in the general population. Moreover, in some families, mutations in other known arRP genes segregated with the disease phenotype. An increasing understanding of causal ABCA4 alleles in arSTGD and arCRD facilitates disease diagnosis and prognosis and also is paramount in selecting patients for emerging clinical trials of therapeutic interventions. Because ABCA4-associated diseases are evolving retinal dystrophies, assessment of age at onset, accurate clinical diagnosis, and genetic testing are crucial. We suggest that ABCA4 mutations may be associated with a retinitis pigmentosa-like phenotype often as a consequence of severe (null) mutations, in cases of long-term, advanced disease, or both. Patients with classical arRP phenotypes, especially from the onset of the disease, should be screened first for mutations in known arRP genes and not ABCA4. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Kinetic and Potential Sputtering Enhancements of Lunar Regolith Erosion: The Contribution of the Heavy Multicharged (Minority) Solar Wind Constituents

NASA Technical Reports Server (NTRS)

Meyer, F. W.; Barghouty, A. F.

2012-01-01

We report preliminary results for H+, Ar+1, Ar+6 and Ar+9 ion sputtering of JSC-1A lunar regolith simulant at solar wind velocities, obtain ed at the ORNL Multicharged Ion Research Facility using quadrupole ma ss spectrometry. The multi-charged Ar ions were used as proxies for i ntermediate mass solar wind multicharged ions. Prior to the Ar beam e xposures, the sample was exposed to high fluence H+ irradiation to si mulate H-loading due to the dominant solar wind constituent. A x80 en hancement of oxygen sputtering by Ar+ over same velocity H+ was measu red and an additional x2 increase for Ar+9 over same velocity Ar+ was demonstrated, giving clear evidence of the importance of potential s puttering by multicharged ions. This enhancement was observed to pers ist to the maximum fluences investigated (approx 10(exp 16)/sq cm). As discussed in a companion abstract by N. Barghouty, such persistent s puttering enhancement has significant implications on weathering and aging of lunar regolith. In addition, XPS measurements showed strong evidence of Fe reduction for those target areas that had been exposed to high fluence Ar+ and Ar+8 beams. Preferential oxidation of the Fe -reduced beam-exposed regions during transfer to the XPS system led t o enhanced O concentrations in those regions as well. On the basis of these very promising preliminary results, a NASA-LASER project on mo re extensive measurements was recently selected for funding. The prop osal expands the collaboration with NASA-MSFC for the simulation effort, and adds a new collaboration with NASA-GSFC for lunar mission-rele vant measurements.

A Test of Sensitivity to Convective Transport in a Global Atmospheric CO2 Simulation

NASA Technical Reports Server (NTRS)

Bian, H.; Kawa, S. R.; Chin, M.; Pawson, S.; Zhu, Z.; Rasch, P.; Wu, S.

2006-01-01

Two approximations to convective transport have been implemented in an offline chemistry transport model (CTM) to explore the impact on calculated atmospheric CO2 distributions. GlobalCO2 in the year 2000 is simulated using theCTM driven by assimilated meteorological fields from the NASA s Goddard Earth Observation System Data Assimilation System, Version 4 (GEOS-4). The model simulates atmospheric CO2 by adopting the same CO2 emission inventory and dynamical modules as described in Kawa et al. (convective transport scheme denoted as Conv1). Conv1 approximates the convective transport by using the bulk convective mass fluxes to redistribute trace gases. The alternate approximation, Conv2, partitions fluxes into updraft and downdraft, as well as into entrainment and detrainment, and has potential to yield a more realistic simulation of vertical redistribution through deep convection. Replacing Conv1 by Conv2 results in an overestimate of CO2 over biospheric sink regions. The largest discrepancies result in a CO2 difference of about 7.8 ppm in the July NH boreal forest, which is about 30% of the CO2 seasonality for that area. These differences are compared to those produced by emission scenario variations constrained by the framework of Intergovernmental Panel on Climate Change (IPCC) to account for possible land use change and residual terrestrial CO2 sink. It is shown that the overestimated CO2 driven by Conv2 can be offset by introducing these supplemental emissions.

Augmented reality visualization of deformable tubular structures for surgical simulation.

PubMed

Ferrari, Vincenzo; Viglialoro, Rosanna Maria; Nicoli, Paola; Cutolo, Fabrizio; Condino, Sara; Carbone, Marina; Siesto, Mentore; Ferrari, Mauro

2016-06-01

Surgical simulation based on augmented reality (AR), mixing the benefits of physical and virtual simulation, represents a step forward in surgical training. However, available systems are unable to update the virtual anatomy following deformations impressed on actual anatomy. A proof-of-concept solution is described providing AR visualization of hidden deformable tubular structures using nitinol tubes sensorized with electromagnetic sensors. This system was tested in vitro on a setup comprised of sensorized cystic, left and right hepatic, and proper hepatic arteries. In the trial session, the surgeon deformed the tubular structures with surgical forceps in 10 positions. The mean, standard deviation, and maximum misalignment between virtual and real arteries were 0.35, 0.22, and 0.99 mm, respectively. The alignment accuracy obtained demonstrates the feasibility of the approach, which can be adopted in advanced AR simulations, in particular as an aid to the identification and isolation of tubular structures. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Exploring the Interaction Mechanism Between Cyclopeptide DC3 and Androgen Receptor Using Molecular Dynamics Simulations and Free Energy Calculations

PubMed Central

Zhang, Huimin; Song, Tianqing; Yang, Yizhao; Fu, Chenggong; Li, Jiazhong

2018-01-01

Androgen receptor (AR) is a key target in the discovery of anti-PCa (Prostate Cancer) drugs. Recently, a novel cyclopeptide Diffusa Cyclotide-3 (DC3), isolated from Hedyotisdiffusa, has been experimentally demonstrated to inhibit the survival and growth of LNCap cells, which typically express T877A-mutated AR, the most frequently detected point mutation of AR in castration-resistant prostate cancer (CRPC). But the interaction mechanism between DC3 and AR is not clear. Here in this study we aim to explore the possible binding mode of DC3 to T877A-mutated AR from molecular perspective. Firstly, homology modeling was employed to construct the three-dimensional structure of the cyclopeptide DC3 using 2kux.1.A as the template. Then molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MM-GBSA) methods were performed to determine the bind site and explore the detailed interaction mechanism of DC3-AR complex. The obtained results suggested that the site formed by H11, loop888-893, and H12 (site 2) was the most possible position of DC3 binding to AR. Besides, hydrogen bonds, hydrophobic, and electrostatic interactions play dominant roles in the recognition and combination of DC3-AR complex. The essential residues dominant in each interaction were specifically revealed. This work facilitates our understanding of the interaction mechanism of DC3 binding to AR at the molecular level and contributes to the rational cyclopeptide drug design for prostate cancer. PMID:29755968

Exploring the Interaction Mechanism between Cyclopeptide DC3 and Androgen Receptor Using Molecular Dynamics Simulations and Free Energy Calculations

NASA Astrophysics Data System (ADS)

Zhang, Huimin; Song, Tianqing; Yang, Yizhao; Fu, Chenggong; Li, Jiazhong

2018-04-01

Androgen receptor (AR) is a key target in the discovery of anti-PCa (Prostate Cancer) drugs. Recently, a novel cyclopeptide Diffusa Cyclotide-3 (DC3), isolated from Hedyotisdiffusa, has been experimentally demonstrated to inhibit the survival and growth of LNCap cells, which typically express T877A-mutated AR, the most frequently detected point mutation of AR in castration-resistant prostate cancer (CRPC). But the interaction mechanism between DC3 and AR is not clear. Here in this study we aim to explore the possible binding mode of DC3 to T877A-mutated AR from molecular perspective. Firstly, homology modeling was employed to construct the three-dimensional structure of the cyclopeptide DC3 using 2kux.1.A as the template. Then molecular docking, molecular dynamics (MD) simulations and molecular mechanics/generalized Born surface area (MM-GBSA) methods were performed to determine the bind site and explore the detailed interaction mechanism of DC3-AR complex. The obtained results suggested that the site formed by H11, loop888-893 and H12 (site 2) was the most possible position of DC3 binding to AR. Besides, hydrogen bonds, hydrophobic and electrostatic interactions play dominant roles in the recognition and combination of DC3-AR complex. The essential residues dominant in each interaction were specifically revealed. This work facilitates our understanding of the interaction mechanism of DC3 binding to AR at the molecular level and contributes to the rational cyclopeptide drug design for prostate cancer.

Exploring the Interaction Mechanism Between Cyclopeptide DC3 and Androgen Receptor Using Molecular Dynamics Simulations and Free Energy Calculations.

PubMed

Zhang, Huimin; Song, Tianqing; Yang, Yizhao; Fu, Chenggong; Li, Jiazhong

2018-01-01

Androgen receptor (AR) is a key target in the discovery of anti-PCa (Prostate Cancer) drugs. Recently, a novel cyclopeptide Diffusa Cyclotide-3 (DC3), isolated from Hedyotisdiffusa , has been experimentally demonstrated to inhibit the survival and growth of LNCap cells, which typically express T877A-mutated AR, the most frequently detected point mutation of AR in castration-resistant prostate cancer (CRPC). But the interaction mechanism between DC3 and AR is not clear. Here in this study we aim to explore the possible binding mode of DC3 to T877A-mutated AR from molecular perspective. Firstly, homology modeling was employed to construct the three-dimensional structure of the cyclopeptide DC3 using 2kux.1.A as the template. Then molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MM-GBSA) methods were performed to determine the bind site and explore the detailed interaction mechanism of DC3-AR complex. The obtained results suggested that the site formed by H11, loop888-893, and H12 (site 2) was the most possible position of DC3 binding to AR. Besides, hydrogen bonds, hydrophobic, and electrostatic interactions play dominant roles in the recognition and combination of DC3-AR complex. The essential residues dominant in each interaction were specifically revealed. This work facilitates our understanding of the interaction mechanism of DC3 binding to AR at the molecular level and contributes to the rational cyclopeptide drug design for prostate cancer.

ntermediate frequency atmospheric disturbances: A dynamical bridge connecting western U.S. extreme precipitation with East Asian cold surges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Tianyu NMI; Evans, Katherine J; Deng, Yi

In this study, an atmospheric river (AR) detection algorithm is developed to investigate the downstream modulation of the eastern North Pacific ARs by another weather extreme, known as the East Asian cold surge (EACS), in both reanalysis data and high-resolution global model simulations. It is shown that following the peak of an EACS, atmospheric disturbances of intermediate frequency (IF; 10 30 day period) are excited downstream. This leads to the formation of a persistent cyclonic circulation anomaly over the eastern North Pacific that dramatically enhances the AR occurrence probability and the surface precipitation over the western U.S. between 30 Nmore » and 50 N. A diagnosis of the local geopotential height tendency further confirms the essential role of IF disturbances in establishing the observed persistent anomaly. This downstream modulation effect is then examined in the two simulations of the National Center for Atmospheric Research Community Climate System Model version 4 with different horizontal resolutions (T85 and T341) for the same period (1979 2005). The connection between EACS and AR is much better captured by the T341 version of the model, mainly due to a better representation of the scale interaction and the characteristics of IF atmospheric disturbances in the higher-resolution model. The findings here suggest that faithful representations of scale interaction in a global model are critical for modeling and predicting the occurrences of hydrological extremes in the western U.S. and for understanding their potential future changes.« less

Regional climate projection of the Maritime Continent using the MIT Regional Climate Model

NASA Astrophysics Data System (ADS)

IM, E. S.; Eltahir, E. A. B.

2014-12-01

Given that warming of the climate system is unequivocal (IPCC AR5), accurate assessment of future climate is essential to understand the impact of climate change due to global warming. Modelling the climate change of the Maritime Continent is particularly challenge, showing a high degree of uncertainty. Compared to other regions, model agreement of future projections in response to anthropogenic emission forcings is much less. Furthermore, the spatial and temporal behaviors of climate projections seem to vary significantly due to a complex geographical condition and a wide range of scale interactions. For the fine-scale climate information (27 km) suitable for representing the complexity of climate change over the Maritime Continent, dynamical downscaling is performed using the MIT regional climate model (MRCM) during two thirty-year period for reference (1970-1999) and future (2070-2099) climate. Initial and boundary conditions are provided by Community Earth System Model (CESM) simulations under the emission scenarios projected by MIT Integrated Global System Model (IGSM). Changes in mean climate as well as the frequency and intensity of extreme climate events are investigated at various temporal and spatial scales. Our analysis is primarily centered on the different behavior of changes in convective and large-scale precipitation over land vs. ocean during dry vs. wet season. In addition, we attempt to find the added value to downscaled results over the Maritime Continent through the comparison between MRCM and CESM projection. Acknowledgements.This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's Center for Environmental Sensing and Modeling interdisciplinary research program.

Structures, bonding, and reaction chemistry of the neutral organogallium(I) compounds (GaAr)n(n = 1 or 2) (Ar = terphenyl or related ligand): an experimental investigation of Ga-Ga multiple bonding.

PubMed

Hardman, Ned J; Wright, Robert J; Phillips, Andrew D; Power, Philip P

2003-03-05

The synthesis, structure, and properties of several new organogallium(I) compounds are reported. The monovalent compounds GaAr* (Ar* = C(6)H(3)-2,6-Trip(2), Trip = C(6)H(2)-2,4,6-Pr(i)()(3), 1), GaAr# (Ar# = C(6)H(3)-2,6(Bu(t)Dipp)(2), Bu(t)Dipp = C(6)H(2)-2,6-Pr(i)(2)-4-Bu(t)(), 4), and the dimeric (GaAr')(2) (Ar' = C(6)H(3)-2,6-Dipp(2), Dipp = C(6)H(3)-2,6-Pr(i)(2), 6) were synthesized by the reaction of "GaI" with (Et(2)O)LiAr*, (Et(2)O)LiAr# (3), or (LiAr')(2). Compounds 1 and 4 were isolated as green crystals, whereas 6 was obtained as a brown-red crystalline solid. All three compounds dissolved in hydrocarbon solvents to give green solutions and almost identical UV/visible spectra. Cryoscopy of 1 and 6 showed that they were monomeric in cyclohexane. Crystals of 1 and 4 were unsuitable for X-ray crystal structure determinations, but an X-ray data set for 6 showed that it was weakly dimerized in the solid with a long Ga-Ga bond of 2.6268(7) A and a trans-bent CGaGaC core array. The 1,2-diiodo-1,2-diaryldigallane compounds [Ga(Ar*)I](2) (2), [Ga(Ar#)I](2) (5), and [Ga(Ar')I](2) (7) were isolated as byproducts of the synthesis of 1, 4, and 6. The crystal structures of 2 and 7 showed that they had planar ICGaGaCI core arrays with Ga-Ga distances near 2.49 A, consistent with Ga-Ga single bonding. Treatment of 1, 4, and 6 with B(C(6)F(5))(3) immediately afforded the 1:1 donor-acceptor complexes ArGa[B(C(6)F(5))(3)] (Ar = Ar*, 8; Ar#, 9; Ar', 10) that featured almost linear gallium coordination, Ga-B distances near the sum of the covalent radii of gallium and boron, as well as some close Ga...F contacts. Compound 1 also reacted with Fe(CO)(5) under ambient conditions to give Ar*GaFe(CO)(4) (11), which had been previously synthesized by the reaction of GaAr*Cl(2) with Na(2)Fe(CO)(4). Reaction of 1 with 2,3-dimethyl-1,3-butadiene afforded the compound [Ar*GaCH(2)C(Me)C(Me)CH(2)]2 (12) that had a 10-membered 1,5-Ga(2)C(8) ring with no Ga-Ga interaction. Stirring 1 or 6 with sodium readily gave Na(2)[Ar*GaGaAr*] (13) and Na(2)(Ar'GaGaAr') (14). The former species 13 had been synthesized previously by reduction of GaAr*Cl(2) with sodium and was described as having a Ga-Ga triple bond because of the short Ga-Ga distance and the electronic relationship between [Ar*GaGaAr*](2-) and the corresponding neutral group 14 alkyne analogues. Compound 14 has a similar structure featuring a trans-bent CGaGaC core, bridged by sodiums which were also coordinated to the flanking aryl rings of the Ar' ligands. The Ga-Ga bond length was found to be 2.347(1) A, which is slightly (ca. 0.02 A) longer than that reported for 13. Reaction of Ga[N(Dipp)C(Me)](2)CH, 15 (i.e., GaN(wedge)NDipp(2)), which is sterically related to 1, 4, and 6, with Fe(CO)(5) yielded Dipp(2)N(wedge)NGaFe(CO)(4) (16), whose Ga-Fe bond is slightly longer than that observed in 11. Reaction of the less bulky LiAr"(Ar"= C(6)H(3)-2,6-Mes(2)) with "GaI" afforded the new paramagnetic cluster Ga(11)Ar(4)" (17). The ready dissociation of 1, 4, and 6 in solution, the long Ga-Ga distance in 6, and the chemistry of these compounds showed that the Ga-Ga bonds are significantly weaker than single bonds. The reduction of 1 and 6 with sodium to give 13 and 14 supplies two electrons to the di-gallium unit to generate a single bond (in addition to the weak interaction in the neutral precursor) with retention of the trans-bent geometry. It was concluded that the stability of 13 and 14 depends on the matching size of the sodium ion, and the presence of Na-Ga and Na-Ar interactions that stabilize their Na(2)Ga(2) core structures.

Performance of Low-Density Parity-Check Coded Modulation

NASA Astrophysics Data System (ADS)

Hamkins, J.

2011-02-01

This article presents the simulated performance of a family of nine AR4JA low-density parity-check (LDPC) codes when used with each of five modulations. In each case, the decoder inputs are codebit log-likelihood ratios computed from the received (noisy) modulation symbols using a general formula which applies to arbitrary modulations. Suboptimal soft-decision and hard-decision demodulators are also explored. Bit-interleaving and various mappings of bits to modulation symbols are considered. A number of subtle decoder algorithm details are shown to affect performance, especially in the error floor region. Among these are quantization dynamic range and step size, clipping degree-one variable nodes, "Jones clipping" of variable nodes, approximations of the min* function, and partial hard-limiting messages from check nodes. Using these decoder optimizations, all coded modulations simulated here are free of error floors down to codeword error rates below 10^{-6}. The purpose of generating this performance data is to aid system engineers in determining an appropriate code and modulation to use under specific power and bandwidth constraints, and to provide information needed to design a variable/adaptive coded modulation (VCM/ACM) system using the AR4JA codes. IPNPR Volume 42-185 Tagged File.txt

Renewable Surface Fluorescence Sandwich Immunoassay Biosensor for Rapid Sensitive Botulinum Toxin Detection in an Automated Fluidic Format

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grate, Jay W.; Warner, Marvin G.; Ozanich, Richard M.

2009-03-05

A renewable surface biosensor for rapid detection of botulinum toxin is described based on fluidic automation of a fluorescence sandwich immunoassay, using a recombinant fragment of the toxin heavy chain as a structurally valid simulant. Monoclonal antibodies AR4 and RAZ1 bind to separate epitopes of both this fragment and the holotoxin. The AR4 antibody was covalently bound to Sepharose beads and used as the capture antibody. A rotating rod flow cell was used to capture these beads delivered as a suspension by the sequential injection flow system, creating a 3.6 microliter column. After perfusing the bead column with sample andmore » washing away the matrix, the column was perfused with Alexa 647 dye-labeled RAZ1 antibody as the reporter. Optical fibers coupled to the rotating rod flow cell at a 90 degree angle to one another delivered excitation light from a HeNe laser and collected fluorescent emission light for detection. After each measurement, the used sepharose beads are released and replaced with fresh beads. In a rapid screening approach to sample analysis, the toxin simulant was detected to concentrations of 10 pM in less than 20 minutes.« less

FASTER: The Fault Tolerant Architecture Simulation Tool for Evaluating Reliability, Introduction and Applications

DTIC Science & Technology

1990-02-01

0 0 Odle arre a 0.415r- M ,SI M 5l dlvi I x MOSI...M V, v-..,ar- cer. a ow a. re~~~relaa..~~6 (ac r r a 4 r. 0 0 ed~v... onln � M0. 0l...63166 TRW ATTN4: Sam Goggin 203 Highway 247 S Warner Robbins GA 31038 Signetics Coro. Attn: Dick Lamoert 4130 South Market Court Sacramentor CA 95834

Hybrid Simulation of Duty Cycle Influences on Pulse Modulated RF SiH4/Ar Discharge

NASA Astrophysics Data System (ADS)

Wang, Xifeng; Song, Yuanhong; Zhao, Shuxia; Dai, Zhongling; Wang, Younian

2016-04-01

A one-dimensional fluid/Monte-Carlo (MC) hybrid model is developed to describe capacitively coupled SiH4/Ar discharge, in which the lower electrode is applied by a RF source and pulse modulated by a square-wave, to investigate the modulation effects of the pulse duty cycle on the discharge mechanism. An electron Monte Carlo simulation is used to calculate the electron energy distribution as a function of position and time phase. Rate coefficients in chemical reactions can then be obtained and transferred to the fluid model for the calculation of electron temperature and densities of different species, such as electrons, ions, and radicals. The simulation results show that, the electron energy distribution f(ɛ) is modulated evidently within a pulse cycle, with its tail extending to higher energies during the power-on period, while shrinking back promptly in the afterglow period. Thus, the rate coefficients could be controlled during the discharge, resulting in modulation of the species composition on the substrate compared with continuous excitation. Meanwhile, more negative ions, like SiH-3 and SiH-2, may escape to the electrodes owing to the collapse of ambipolar electric fields, which is beneficial to films deposition. Pulse modulation is thus expected to provide additional methods to customize the plasma densities and components. supported by National Natural Science Foundation of China (No. 11275038)

Ar-39 - Ar-40 Evidence for an Approximately 4.26 Ga Impact Heating Event on the LL Parent Body

NASA Technical Reports Server (NTRS)

Dixon, E. T.; Bogard, D. D.; Rubin, A. E.

2003-01-01

Miller Range 99301 is a type 6, unbrecciated LL chondrite. MIL 99301 is of interest because some compositional and petrographic features suggest it experienced rather high shock grades, whereas other features suggest it is relatively unshocked. Inconsistent shock indicators could be explained if MIL 99301 was shocked but then partly annealed by heat produced by impacts on the parent body. The hypothesis that MIL 99301 experienced high temperature metamorphism (type 6) followed by a later shock event that heated, but did not melt, the constituent feldspar can be evaluated using (39)Ar-(40)Ar chronology. This is because (39)Ar-(40)Ar ages of shocked ordinary chondrites are generally <4.2 Ga, whereas (39)Ar-(40)Ar ages of unshocked meteorites are generally older, and between 4.52 - 4.38 Ga.

The Potential for Methane Isotopologue Channels in GOSAT-2

NASA Astrophysics Data System (ADS)

Malina, Edward; Yoshida, Yukio; Matsunaga, Tsuneo; Muller, Jan-Peter

2017-04-01

Of the major Greenhouse Gases (GHGs) currently considered as having a major impact on atmospheric chemistry, Methane is amongst the most important (IPCC, 2014). Methane concentration in the atmosphere has been documented to be rising steadily over the past century, aside from an unexplained short period in the middle of the last decade (Heimann., 2011), leading to renewed efforts to understand global atmospheric Methane. Atmospheric Methane is primarily composed of two key isotopologues, 12CH4 and 13CH4, which have a natural abundance of about 98% and 1.1% respectively. It is a well-established fact that different sources of Methane (i.e. biogenic sources such as methanogens, or non-biogenic such as industrial hydrocarbon burning) vary in the abundance of these isotopologues (Etiope, 2009). The global identification of the ratios of these isotopologues could vastly increase knowledge of global Methane sources, and shed some light on global Methane growth. GOSAT-2 due to be launched in 2018 is a follow on from the original GOSAT mission launched in 2009. GOSAT-2 aims to continue the legacy of GOSAT by providing global measurements of Methane and Carbon Dioxide on a global basis in order to monitor GHG emissions. GOSAT-2 in the context of this study has a significant advantage over GOSAT, which is the extension of the sensitivity of band 3 to 2330nm from 2080nm where significant numbers of Methane spectral lines are located. In this study we apply the well-established Information Content (IC) analysis techniques originally proposed by Rodgers (2000) to determine the potential benefit of retrieving total column Methane isotopologue concentrations assuming bands 2 and 3 of the GOSAT-2/TANSO-FTS-2 instrument. The value of such studies has been proven on multiple occasions and can provide guidance on appropriate potential retrieval setups. Due to the fact that there has been limited research in this area, no 'a priori' state vectors or Variance Covariance Matrices (VCMs) appropriate for isotopologues have been defined previously, we therefore test a number VCMs in order to explore the constraints on retrieving independent information in the total column based on the IC analysis. This analysis and VCM variations also provide the opportunity to explore the potential errors associated with retrievals of isotopologues. Based on this study we will comment on the feasibility of Methane isotopologues retrieval with GOSAT-2 under a range of atmospheric conditions, instrument geometry and VCM setups, as well as the errors associated with these conditions. References: Etiope, G. (2009) 'Natural emissions of methane from geological seepage in Europe', Atmospheric Environment, 43(7), pp. 1430-1443. doi: 10.1016/j.atmosenv.2008.03.014. Heimann, M. (2011) 'Atmospheric science: Enigma of the recent methane budget', Nature, 476(7359), pp. 157-158. doi: 10.1038/476157a. IPCC. Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Available online: https://ipcc-wg2.gov/AR5/report/ Rodgers, C.D. (2000) Inverse methods for atmospheric sounding: Theory and practice. Singapore, Singapore: World Scientific Publishing Company.

Climate Golden Age or Greenhouse Gas Dark Age Legacy?

NASA Astrophysics Data System (ADS)

Carter, P.

2016-12-01

Relying on the IPCC Assessments, this paper assesses legacy from total committed global warming over centuries, correlated with comprehensive projected impacts. Socio-economic inertia, climate system inertia, atmospheric greenhouse gas (GHG) concentrations, amplifying feedback emissions, and unmasking of cooling aerosols are determinants. Stabilization of global temperature (and ocean acidification for CO2) requires emissions of "long lived greenhouse gases" to be "about zero," including feedbacks. "The feedback … is positive" this century; many large feedback sources tend to be self- and inter-reinforcing. Only timely total conversion of all fossil fuel power to clean, virtually zero-carbon renewable power can achieve virtual zero carbon emissions. This results in multiple, increasing benefits for the entire world population of today's and all future generations, as laid out here. Conversions of methane- and nitrous oxide-emitting sources have large benefits. Without timely conversion to virtual zero emissions, the global climate and ocean disruptions are predicted to become progressively more severe and practically irreversible. "Continued emission of greenhouse gases will increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems." Crop yields in all main food-producing regions are projected to decline progressively with rising temperature (as proxy to multiple adverse effects) (AR5). Ocean heating, acidification, and de-oxygenation are projected to increase under all scenarios, as is species extinction. The legacy for humanity depends on reducing long-lived global emissions fast enough to virtual zero. Today's surface warming with unprecedented and accelerating atmospheric GHG concentrations requires an immediate response. The only IPCC scenario to possibly meet this and not exceed 2ºC by and after 2100 is the best-case RCP2.6, which requires CO2 eq. emissions to peak right away and decline at the latest by 2020.

iRODS-Based Climate Data Services and Virtualization-as-a-Service in the NASA Center for Climate Simulation

NASA Astrophysics Data System (ADS)

Schnase, J. L.; Duffy, D. Q.; Tamkin, G. S.; Strong, S.; Ripley, D.; Gill, R.; Sinno, S. S.; Shen, Y.; Carriere, L. E.; Brieger, L.; Moore, R.; Rajasekar, A.; Schroeder, W.; Wan, M.

2011-12-01

Scientific data services are becoming an important part of the NASA Center for Climate Simulation's mission. Our technological response to this expanding role is built around the concept of specialized virtual climate data servers, repetitive cloud provisioning, image-based deployment and distribution, and virtualization-as-a-service. A virtual climate data server is an OAIS-compliant, iRODS-based data server designed to support a particular type of scientific data collection. iRODS is data grid middleware that provides policy-based control over collection-building, managing, querying, accessing, and preserving large scientific data sets. We have developed prototype vCDSs to manage NetCDF, HDF, and GeoTIF data products. We use RPM scripts to build vCDS images in our local computing environment, our local Virtual Machine Environment, NASA's Nebula Cloud Services, and Amazon's Elastic Compute Cloud. Once provisioned into these virtualized resources, multiple vCDSs can use iRODS's federation and realized object capabilities to create an integrated ecosystem of data servers that can scale and adapt to changing requirements. This approach enables platform- or software-as-a-service deployment of the vCDSs and allows the NCCS to offer virtualization-as-a-service, a capacity to respond in an agile way to new customer requests for data services, and a path for migrating existing services into the cloud. We have registered MODIS Atmosphere data products in a vCDS that contains 54 million registered files, 630TB of data, and over 300 million metadata values. We are now assembling IPCC AR5 data into a production vCDS that will provide the platform upon which NCCS's Earth System Grid (ESG) node publishes to the extended science community. In this talk, we describe our approach, experiences, lessons learned, and plans for the future.

Introduction to the SONEX (Subsonic Assessment Ozone and Nitrogen Oxides Experiment) and POLINAT-2 (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) Special Issue

NASA Technical Reports Server (NTRS)

Thompson, Anne M.; Singh, Hanwant B.; Schlager, Hans; Einaudi, Franco (Technical Monitor)

2000-01-01

Emissions of atmospheric species from the engines of subsonic aircraft at cruise altitude (roughly, above seven kilometers) are of concern to scientists, the aviation industry and policymakers for two reasons. First, water vapor, soot and sulfur oxides, and related heterogeneous processes, may modify clouds and aerosols enough to perturb radiative forcing in the UT/LS (upper troposphere/lower stratosphere). A discussion of these phenomena appears in Chapter 3 of the IPCC Aviation Assessment (1999). An airborne campaign conducted to evaluate aviation effects on contrail, cirrus and cloud formation, is described in Geophysical Research Letters. The second concern arises from subsonic aircraft emissions of nitrogen oxides (NO + NO2 = NO(sub x)), CO, and hydrocarbons. These species may add to the background mixture of photochemically reactive species that form ozone. In the UT/LS, ozone is a highly effective greenhouse gas. The impacts of subsonic aircraft emissions on tropospheric NO(sub x) and ozone budgets have been studied with models that focus on UT chemistry [e.g. see discussions of individual models in Brasseur et al., 1998; Friedl et al., 1997; IPCC, 1999]. Depending on the model used, projected increases in the global subsonic aircraft fleet from 1992 to 2015 will lead to a 50-100 pptv increase in UT/LS NO. at 12 km (compared to 50-150 pptv background) in northern hemisphere midlatitudes. The corresponding 12-km ozone increase is 7-11 ppbv, or 5-10% (Chapter 4 in IPCC, 1999). Two major sources of uncertainties in model estimates of aviation effects are: (1) the often limited degree to which global models - the scale required to evaluate aircraft emissions - realistically simulate atmospheric transport and other physical processes; (2) limited UT/LS observations of trace gases with which to evaluate model performance. In response to the latter deficiency, a number of airborne campaigns aimed at elucidating the effect of aircraft on atmospheric nitrogen oxides and ozone were performed between 1990 and 1996 (see descriptions in Friedl et al., 1997; Brasseur et al., 1998).

Expression of alpha-AR subtypes in T lymphocytes and role of the alpha-ARs in mediating modulation of T cell function.

PubMed

Bao, Jing-Yin; Huang, Yan; Wang, Feng; Peng, Yu-Ping; Qiu, Yi-Hua

2007-01-01

Previous work in our laboratory has shown that alpha-adrenoreceptors (alpha-ARs) and beta-ARs exist on lymphocytes from functional profile, and that the receptors mediate the regulation of lymphocyte function by catecholamines. In the present study, we directly examined the expression of alpha-AR subtypes, alpha(1)-AR and alpha(2)-AR mRNAs, in T lymphocytes and explored the roles of the alpha-AR subtypes and intracellular signal transduction mechanisms linked to the receptors in mediating the modulation of T lymphocyte function. T lymphocytes from mesenteric lymph nodes of rats were purified by using a nylon wool column. Reverse transcription polymerase chain reaction was used to detect the expression of alpha(1)-AR and alpha(2)-AR mRNAs in the freshly isolated T cells and the mitogen concanavalin A (Con A)-activated lymphocytes. Colorimetric methylthiazoletetrazolium assay was employed to measure lymphocyte proliferation induced by Con A. Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) levels in the Con A-stimulated lymphocyte culture supernatants were examined by enzyme-linked immunosorbent assay. T cells expressed both alpha(1)-AR and alpha(2)-AR mRNAs. The expression of both alpha(1)-AR and alpha(2)-AR mRNAs was significantly higher in the Con A-activated lymphocytes than in the resting lymphocytes. Phenylephrine, a selective alpha(1)-AR agonist, had no evident effect on lymphocyte proliferation nor on IFN-gamma and IL-4 production induced by Con A. However, the selective alpha(2)-AR agonist clonidine attenuated Con A-induced lymphocyte proliferation as well as IFN-gamma and IL-4 production. The inhibited lymphocyte proliferation and IFN-gamma and IL-4 production by clonidine were blocked by yohimbine, an alpha(2)-AR antagonist. Either phospholipase C inhibitor U-73122 or protein kinase C inhibitor chelerythrine partially prevented the suppressive effect of clonidine on Con A-stimulated lymphocyte proliferation and IL-4 production. T lymphocytes express both alpha(1)-ARs and alpha(2)-ARs, but only the alpha(2)-ARs participate in the suppressive modulation of lymphocyte proliferation and cytokine production in vitro. The inhibitory effect of alpha(2)-AR stimulation on lymphocyte function is partially mediated via the phospholipase C-protein kinase C pathway. (c) 2008 S. Karger AG, Basel.

Development of municipal solid waste classification in Korea based on fossil carbon fraction.

PubMed

Lee, Jeongwoo; Kang, Seongmin; Kim, Seungjin; Kim, Ki-Hyun; Jeon, Eui-Chan

2015-10-01

Environmental problems and climate change arising from waste incineration are taken quite seriously in the world. In Korea, the waste disposal methods are largely classified into landfill, incineration, recycling, etc. and the amount of incinerated waste has risen by 24.5% from 2002. In the analysis of CO₂emissions estimations of waste incinerators fossil carbon content are main factor by the IPCC. FCF differs depending on the characteristics of waste in each country, and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration. The characteristics possible for sorting were classified according to FCF and form. The characteristics sorted according to fossil carbon fraction were paper, textiles, rubber, and leather. Paper was classified into pure paper and processed paper; textiles were classified into cotton and synthetic fibers; and rubber and leather were classified into artificial and natural. The analysis of FCF was implemented by collecting representative samples from each classification group, by applying the 14C method, and using AMS equipment. And the analysis values were compared with the default values proposed by the IPCC. In this study of garden and park waste and plastics, the differences were within the range of the IPCC default values or the differences were negligible. However, coated paper, synthetic textiles, natural rubber, synthetic rubber, artificial leather, and other wastes showed differences of over 10% in FCF content. IPCC is comprised of largely 9 types of qualitative classifications, in emissions estimation a great difference can occur from the combined characteristics according with the existing IPCC classification system by using the minutely classified waste characteristics as in this study. Fossil carbon fraction (FCF) differs depending on the characteristics of waste in each country; and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration.

Five millennia of frozen vegetation and fire dynamics from an ice core in the Mongolian Altai

NASA Astrophysics Data System (ADS)

Brügger, S. O.; Gobet, E.; Sigl, M.; Osmont, D.; Papina, T.; Rudaya, N.; Schwikowski, M.; Tinner, W.

2017-12-01

The steppes of the Altai region in Central Asia are highly vulnerable to e.g. drought and overgrazing. Degradation during the past decades may undermine their resilience under global change conditions. Knowledge about past vegetation and fire dynamics in Mongolian Altai may contribute to a better understanding of future climate and human impact responses, however, paleo records are scarce in the area. Our novel high-alpine ice record from Tsambagarav glacier (48°39.338'N, 90°50.826'E, 4130m asl) in the Mongolian Altai provides unique paleoenvironmental informations at the landscape scale. The site is surrounded by dry steppes with scattered boreal tree stands. We assume that the site collects pollen and spores within several hundred km. The archive provides an exceptional temporal resolution with a sound chronology covering the past 5500 years (Herren et al. 2013). Microfossil analysis allows to reconstruct large-scale fire and vegetation dynamics to gain a better understanding of the timing and causes of late Holocene response variability. We use pollen as proxies for vegetation composition and structure, microscopic charcoal as a proxy for fire activity (Eichler et al. 2011), and spheroidal carbonaceous particles (SCPs or soots) as a proxy for fossil fuel combustion. Here we present the first microscopic charcoal record from Mongolia and link it to vegetation dynamics of the past. The reconstructed mid to late Holocene forest collapses likely in response to climate change underscore the vulnerability of relict forest ecosystems in the Mongolian Altai. Our multiproxy-study suggests that moisture is more important than temperature for forest preservation. The lacking resilience of vegetation to moisture changes in the past emphasizes the vulnerability of large forests in neighboring dry areas such as the Russian Altai, if global warming is associated to moisture declines as future projections forecast (IPCC; Climate Change 2013). References: Eichler et al. (2011). An ice-core based history of Siberian forest fires since AD 1250. Quat Sci Rev 30(9) Herren et al. (2013). The onset of Neoglaciation 6000 years ago in western Mongolia revealed by an ice core from the Tsambagarav mountain range. Quat Sci Rev 69 IPCC; Climate Change (2013): The Physical Science Basis. IPCC Working Group I Contribution to AR5

Distinct physiological effects of β1- and β2-adrenoceptors in mouse ventricular myocytes: insights from a compartmentalized mathematical model.

PubMed

Rozier, Kelvin; Bondarenko, Vladimir E

2017-05-01

The β 1 - and β 2 -adrenergic signaling systems play different roles in the functioning of cardiac cells. Experimental data show that the activation of the β 1 -adrenergic signaling system produces significant inotropic, lusitropic, and chronotropic effects in the heart, whereas the effects of the β 2 -adrenergic signaling system is less apparent. In this paper, a comprehensive compartmentalized experimentally based mathematical model of the combined β 1 - and β 2 -adrenergic signaling systems in mouse ventricular myocytes is developed to simulate the experimental findings and make testable predictions of the behavior of the cardiac cells under different physiological conditions. Simulations describe the dynamics of major signaling molecules in different subcellular compartments; kinetics and magnitudes of phosphorylation of ion channels, transporters, and Ca 2+ handling proteins; modifications of action potential shape and duration; and [Ca 2+ ] i and [Na + ] i dynamics upon stimulation of β 1 - and β 2 -adrenergic receptors (β 1 - and β 2 -ARs). The model reveals physiological conditions when β 2 -ARs do not produce significant physiological effects and when their effects can be measured experimentally. Simulations demonstrated that stimulation of β 2 -ARs with isoproterenol caused a marked increase in the magnitude of the L-type Ca 2+ current, [Ca 2+ ] i transient, and phosphorylation of phospholamban only upon additional application of pertussis toxin or inhibition of phosphodiesterases of type 3 and 4. The model also made testable predictions of the changes in magnitudes of [Ca 2+ ] i and [Na + ] i fluxes, the rate of decay of [Na + ] i concentration upon both combined and separate stimulation of β 1 - and β 2 -ARs, and the contribution of phosphorylation of PKA targets to the changes in the action potential and [Ca 2+ ] i transient. Copyright © 2017 the American Physiological Society.

Simulation study of 3-5 keV x-ray conversion efficiency from Ar K-shell vs. Ag L-shell targets on the National Ignition Facility laser

NASA Astrophysics Data System (ADS)

Kemp, G. E.; Colvin, J. D.; Fournier, K. B.; May, M. J.; Barrios, M. A.; Patel, M. V.; Scott, H. A.; Marinak, M. M.

2015-05-01

Tailored, high-flux, multi-keV x-ray sources are desirable for studying x-ray interactions with matter for various civilian, space and military applications. For this study, we focus on designing an efficient laser-driven non-local thermodynamic equilibrium 3-5 keV x-ray source from photon-energy-matched Ar K-shell and Ag L-shell targets at sub-critical densities (˜nc/10) to ensure supersonic, volumetric laser heating with minimal losses to kinetic energy, thermal x rays and laser-plasma instabilities. Using Hydra, a multi-dimensional, arbitrary Lagrangian-Eulerian, radiation-hydrodynamics code, we performed a parameter study by varying initial target density and laser parameters for each material using conditions readily achievable on the National Ignition Facility (NIF) laser. We employ a model, benchmarked against Kr data collected on the NIF, that uses flux-limited Lee-More thermal conductivity and multi-group implicit Monte-Carlo photonics with non-local thermodynamic equilibrium, detailed super-configuration accounting opacities from Cretin, an atomic-kinetics code. While the highest power laser configurations produced the largest x-ray yields, we report that the peak simulated laser to 3-5 keV x-ray conversion efficiencies of 17.7% and 36.4% for Ar and Ag, respectively, occurred at lower powers between ˜100-150 TW. For identical initial target densities and laser illumination, the Ag L-shell is observed to have ≳10× higher emissivity per ion per deposited laser energy than the Ar K-shell. Although such low-density Ag targets have not yet been demonstrated, simulations of targets fabricated using atomic layer deposition of Ag on silica aerogels (˜20% by atomic fraction) suggest similar performance to atomically pure metal foams and that either fabrication technique may be worth pursuing for an efficient 3-5 keV x-ray source on NIF.

The impact of past and future climate change on global human mortality due to ozone and PM2.5 outdoor air pollution

NASA Astrophysics Data System (ADS)

Silva, R.; West, J.; Anenberg, S.; Lamarque, J.; Shindell, D. T.; Bergmann, D. J.; Berntsen, T.; Cameron-Smith, P. J.; Collins, B.; Ghan, S. J.; Josse, B.; Nagashima, T.; Naik, V.; Plummer, D.; Rodriguez, J. M.; Szopa, S.; Zeng, G.

2012-12-01

Climate change can adversely affect air quality, through changes in meteorology, atmospheric chemistry, and emissions. Future changes in air pollutant emissions will also profoundly influence air quality. These changes in air quality can affect human health, as exposure to ground-level ozone and fine particulate matter (PM2.5) has been associated with premature human mortality. Here we will quantify the global mortality impacts of past and future climate change, considering the effects of climate change on air quality isolated from emission changes. The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has simulated the past and future surface concentrations of ozone and PM2.5 from each of several GCMs, for emissions from 1850 ("preindustrial") to 2000 ("present-day"), and for the IPCC AR5 Representative Concentration Pathways (RCPs) scenarios to 2100. We will use ozone and PM2.5 concentrations from simulations from five or more global models of atmospheric dynamics and chemistry, for a base year (present-day), pre-industrial conditions, and future scenarios, considering changes in climate and emissions. We will assess the mortality impacts of past climate change by using one simulation ensemble with present emissions and climate and one with present emissions but 1850 climate. We will similarly quantify the potential impacts of future climate change under the four RCP scenarios in 2030, 2050 and 2100. All model outputs will be regridded to the same resolution to estimate multi-model medians and range in each grid cell. Resulting premature deaths will be calculated using these medians along with epidemiologically-derived concentration-response functions, and present-day or future projections of population and baseline mortality rates, considering aging and transitioning disease rates over time. The spatial distributions of current and future global premature mortalities due to ozone and PM2.5 outdoor air pollution will be presented separately. These results will strengthen our understanding of the impacts of climate change today, and in future years considering different plausible scenarios.

Early Thermal History of Eucrites by Ar-39-Ar-40

NASA Technical Reports Server (NTRS)

Bogard, D. D.; Garrison, D. H.

2001-01-01

Ar-39-Ar-40 ages for Piplia Kalan (3.58 +/- 0.02 Ga) and two other eucrites indicate later impact resetting. Older Ar-39-Ar-40 ages exist for the Moama cumulate eucrite (4.42 +/- 0.01 Ga) and the PCA82502 (4.506 +/- 0.009 Ga) and PCA91007 non-brecciated eucrites. Additional information is contained in the original extended abstract.

Mathematical simulation of the amplification of 1790-nm laser radiation in a nuclear-excited He - Ar plasma containing nanoclusters of uranium compounds

NASA Astrophysics Data System (ADS)

Kosarev, V. A.; Kuznetsova, E. E.

2014-02-01

The possibility of applying dusty active media in nuclearpumped lasers has been considered. The amplification of 1790-nm radiation in a nuclear-excited dusty He - Ar plasma is studied by mathematical simulation. The influence of nanoclusters on the component composition of the medium and the kinetics of the processes occurring in it is analysed using a specially developed kinetic model, including 72 components and more than 400 reactions. An analysis of the results indicates that amplification can in principle be implemented in an active laser He - Ar medium containing 10-nm nanoclusters of metallic uranium and uranium dioxide.

First-Person Point-of-View-Augmented Reality for Central Line Insertion Training: A Usability and Feasibility Study.

PubMed

Rochlen, Lauryn R; Levine, Robert; Tait, Alan R

2017-02-01

The value of simulation in medical education and procedural skills training is well recognized. Despite this, many mannequin-based trainers are limited by the inability of the trainee to view the internal anatomical structures. This study evaluates the usability and feasibility of a first-person point-of-view-augmented reality (AR) trainer on needle insertion as a component of central venous catheter placement. Forty subjects, including medical students and anesthesiology residents and faculty, participated. Augmented reality glasses were provided through which the relevant internal anatomical landmarks were projected. After a practice period, participants were asked to place the needle in the mannequin without the benefit of the AR-projected internal anatomy. The ability of the trainees to correctly place the needle was documented. Participants also completed a short survey describing their perceptions of the AR technology. Participants reported that the AR technology was realistic (77.5%) and that the ability to view the internal anatomy was helpful (92.5%). Furthermore, 85% and 82.1%, respectively, believed that the AR technology promoted learning and should be incorporated into medical training. The ability to successfully place the needle was similar between experienced and nonexperienced participants; however, less experienced participants were more likely to inadvertently puncture the carotid artery. Results of this pilot study demonstrated the usability and feasibility of AR technology as a potentially important adjunct to simulated medical skills training. Further development and evaluation of this innovative technology under a variety of simulated medical training settings would be an important next step.

A Multilevel AR(1) Model: Allowing for Inter-Individual Differences in Trait-Scores, Inertia, and Innovation Variance.

PubMed

Jongerling, Joran; Laurenceau, Jean-Philippe; Hamaker, Ellen L

2015-01-01

In this article we consider a multilevel first-order autoregressive [AR(1)] model with random intercepts, random autoregression, and random innovation variance (i.e., the level 1 residual variance). Including random innovation variance is an important extension of the multilevel AR(1) model for two reasons. First, between-person differences in innovation variance are important from a substantive point of view, in that they capture differences in sensitivity and/or exposure to unmeasured internal and external factors that influence the process. Second, using simulation methods we show that modeling the innovation variance as fixed across individuals, when it should be modeled as a random effect, leads to biased parameter estimates. Additionally, we use simulation methods to compare maximum likelihood estimation to Bayesian estimation of the multilevel AR(1) model and investigate the trade-off between the number of individuals and the number of time points. We provide an empirical illustration by applying the extended multilevel AR(1) model to daily positive affect ratings from 89 married women over the course of 42 consecutive days.

A novel augmented reality simulator for skills assessment in minimal invasive surgery.

PubMed

Lahanas, Vasileios; Loukas, Constantinos; Smailis, Nikolaos; Georgiou, Evangelos

2015-08-01

Over the past decade, simulation-based training has come to the foreground as an efficient method for training and assessment of surgical skills in minimal invasive surgery. Box-trainers and virtual reality (VR) simulators have been introduced in the teaching curricula and have substituted to some extent the traditional model of training based on animals or cadavers. Augmented reality (AR) is a new technology that allows blending of VR elements and real objects within a real-world scene. In this paper, we present a novel AR simulator for assessment of basic laparoscopic skills. The components of the proposed system include: a box-trainer, a camera and a set of laparoscopic tools equipped with custom-made sensors that allow interaction with VR training elements. Three AR tasks were developed, focusing on basic skills such as perception of depth of field, hand-eye coordination and bimanual operation. The construct validity of the system was evaluated via a comparison between two experience groups: novices with no experience in laparoscopic surgery and experienced surgeons. The observed metrics included task execution time, tool pathlength and two task-specific errors. The study also included a feedback questionnaire requiring participants to evaluate the face-validity of the system. Between-group comparison demonstrated highly significant differences (<0.01) in all performance metrics and tasks denoting the simulator's construct validity. Qualitative analysis on the instruments' trajectories highlighted differences between novices and experts regarding smoothness and economy of motion. Subjects' ratings on the feedback questionnaire highlighted the face-validity of the training system. The results highlight the potential of the proposed simulator to discriminate groups with different expertise providing a proof of concept for the potential use of AR as a core technology for laparoscopic simulation training.

Heterologous desensitization of cardiac β-adrenergic signal via hormone-induced βAR/arrestin/PDE4 complexes

PubMed Central

Shi, Qian; Li, Minghui; Mika, Delphine; Fu, Qin; Kim, Sungjin; Phan, Jason; Shen, Ao; Vandecasteele, Gregoire; Xiang, Yang K.

2017-01-01

Aims Cardiac β-adrenergic receptor (βAR) signalling is susceptible to heterologous desensitization by different neurohormonal stimuli in clinical conditions associated with heart failure. We aim to examine the underlying mechanism of cross talk between βARs and a set of G-protein coupled receptors (GPCRs) activated by hormones/agonists. Methods and results Rat ventricular cardiomyocytes were used to determine heterologous phosphorylation of βARs under a series of GPCR agonists. Activation of Gs-coupled dopamine receptor, adenosine receptor, relaxin receptor and prostaglandin E2 receptor, and Gq-coupled α1 adrenergic receptor and angiotensin II type 1 receptor promotes phosphorylation of β1AR and β2AR at putative protein kinase A (PKA) phosphorylation sites; but activation of Gi-coupled α2 adrenergic receptor and activation of protease-activated receptor does not. The GPCR agonists that promote β2AR phosphorylation effectively inhibit βAR agonist isoproterenol-induced PKA phosphorylation of phospholamban and contractile function in ventricular cardiomyocytes. Heterologous GPCR stimuli have minimal to small effect on isoproterenol-induced β2AR activation and G-protein coupling for cyclic adenosine monophosphate (cAMP) production. However, these GPCR stimuli significantly promote phosphorylation of phosphodiesterase 4D (PDE4D), and recruit PDE4D to the phosphorylated β2AR in a β-arrestin 2 dependent manner without promoting β2AR endocytosis. The increased binding between β2AR and PDE4D effectively hydrolyzes cAMP signal generated by subsequent stimulation with isoproterenol. Mutation of PKA phosphorylation sites in β2AR, inhibition of PDE4, or genetic ablation of PDE4D or β-arrestin 2 abolishes this heterologous inhibitory effect. Ablation of β-arrestin 2 or PDE4D gene also rescues β-adrenergic stimuli-induced myocyte contractile function. Conclusions These data reveal essential roles of β-arrestin 2 and PDE4D in a common mechanism for heterologous desensitization of cardiac βARs under hormonal stimulation, which is associated with impaired cardiac function during the development of pathophysiological conditions. PMID:28339772

Heterologous desensitization of cardiac β-adrenergic signal via hormone-induced βAR/arrestin/PDE4 complexes.

PubMed

Shi, Qian; Li, Minghui; Mika, Delphine; Fu, Qin; Kim, Sungjin; Phan, Jason; Shen, Ao; Vandecasteele, Gregoire; Xiang, Yang K

2017-05-01

Cardiac β-adrenergic receptor (βAR) signalling is susceptible to heterologous desensitization by different neurohormonal stimuli in clinical conditions associated with heart failure. We aim to examine the underlying mechanism of cross talk between βARs and a set of G-protein coupled receptors (GPCRs) activated by hormones/agonists. Rat ventricular cardiomyocytes were used to determine heterologous phosphorylation of βARs under a series of GPCR agonists. Activation of Gs-coupled dopamine receptor, adenosine receptor, relaxin receptor and prostaglandin E2 receptor, and Gq-coupled α1 adrenergic receptor and angiotensin II type 1 receptor promotes phosphorylation of β1AR and β2AR at putative protein kinase A (PKA) phosphorylation sites; but activation of Gi-coupled α2 adrenergic receptor and activation of protease-activated receptor does not. The GPCR agonists that promote β2AR phosphorylation effectively inhibit βAR agonist isoproterenol-induced PKA phosphorylation of phospholamban and contractile function in ventricular cardiomyocytes. Heterologous GPCR stimuli have minimal to small effect on isoproterenol-induced β2AR activation and G-protein coupling for cyclic adenosine monophosphate (cAMP) production. However, these GPCR stimuli significantly promote phosphorylation of phosphodiesterase 4D (PDE4D), and recruit PDE4D to the phosphorylated β2AR in a β-arrestin 2 dependent manner without promoting β2AR endocytosis. The increased binding between β2AR and PDE4D effectively hydrolyzes cAMP signal generated by subsequent stimulation with isoproterenol. Mutation of PKA phosphorylation sites in β2AR, inhibition of PDE4, or genetic ablation of PDE4D or β-arrestin 2 abolishes this heterologous inhibitory effect. Ablation of β-arrestin 2 or PDE4D gene also rescues β-adrenergic stimuli-induced myocyte contractile function. These data reveal essential roles of β-arrestin 2 and PDE4D in a common mechanism for heterologous desensitization of cardiac βARs under hormonal stimulation, which is associated with impaired cardiac function during the development of pathophysiological conditions. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

Dressing the Coronal Magnetic Extrapolations of Active Regions with a Parameterized Thermal Structure

NASA Astrophysics Data System (ADS)

Nita, Gelu M.; Viall, Nicholeen M.; Klimchuk, James A.; Loukitcheva, Maria A.; Gary, Dale E.; Kuznetsov, Alexey A.; Fleishman, Gregory D.

2018-01-01

The study of time-dependent solar active region (AR) morphology and its relation to eruptive events requires analysis of imaging data obtained in multiple wavelength domains with differing spatial and time resolution, ideally in combination with 3D physical models. To facilitate this goal, we have undertaken a major enhancement of our IDL-based simulation tool, GX_Simulator, previously developed for modeling microwave and X-ray emission from flaring loops, to allow it to simulate quiescent emission from solar ARs. The framework includes new tools for building the atmospheric model and enhanced routines for calculating emission that include new wavelengths. In this paper, we use our upgraded tool to model and analyze an AR and compare the synthetic emission maps with observations. We conclude that the modeled magneto-thermal structure is a reasonably good approximation of the real one.

Mono- and dinuclear tetraphosphabutadiene ferrate anions.

PubMed

Chakraborty, Uttam; Leitl, Julia; Mühldorf, Bernd; Bodensteiner, Michael; Pelties, Stefan; Wolf, Robert

2018-03-12

Reduction of [Cp Ar Fe(μ-Br)] 2 (1, Cp Ar = C 5 (C 6 H 4 -4-Et) 5 ) by potassium napthalenide, followed by the addition of white phosphorus, affords [K(18-c-6){Cp Ar Fe(η 4 -P 4 )}] (2, 18-c-6 = [18]crown-6), which features a planar cyclo-P 4 2- ligand. The related diiron complex [Na 2 (THF) 5 (Cp Ar Fe) 2 (μ,η 4:4 -P 4 )] (3) was obtained by reducing 1 with sodium amalgam in the presence of P 4 . Protonation of 3 affords [Na(THF) 3 ][(Cp Ar Fe) 2 (μ,η 4:4 -P 4 )(H)] (4), while the reaction of 3 with trimethylchlorosilane gives the nortricyclane compound P 7 (SiMe 3 ) 3 as the main product.

Selective dry etching of III-V nitrides in Cl{sub 2}/Ar, CH{sub 4}/H{sub 2}/Ar, ICi/Ar, and IBr/Ar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vartuli, C.B.; Pearton, S.J.; MacKenzie, J.D.

1996-10-01

The selectivity for etching the binary (GaN, AlN, and InN) and ternary nitrides (InGaN and InAlN) relative to each other in Cl{sub 2}/Ar, CH{sub 4}/H{sub 2}/Ar, ICl/Ar, or IBr/Ar electron cyclotron resonance (ECR) plasmas, and Cl{sub 2}/Ar or CH{sub 4}/H{sub 2}/Ar reactive ion (RIE) plasmas was investigated. Cl-based etches appear to be the best choice for maximizing the selectivity of GaN over the other nitrides. GaN/AlN and GaN/InGaN etch rate ratios of {approximately} 10 were achieved at low RF power in Cl{sub 2}/Ar under ECR and RIE conditions, respectively. GaN/InN selectivity of 10 was found in ICl under ECR conditions.more » A relatively high selectivity (> 6) of InN/GaN was achieved in CH{sub 4}/H{sub 2}/Ar under ECR conditions at low RF powers (50 W). Since the high bond strengths of the nitrides require either high ion energies or densities to achieve practical etch rates it is difficult to achieve high selectivities.« less

Hydrogen and Ethene Plasma Assisted Ignition by NS discharge at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Starikovskiy, Andrey

2015-09-01

The kinetics of ignition in lean H2:O2:Ar and C2H4:O2:Ar mixtures has been studied experimentally and numerically after a high-voltage nanosecond discharge. The ignition delay time behind a reflected shock wave was measured with and without the discharge. It was shown that the initiation of the discharge with a specific deposited energy of 10 - 30 mJ/cm3 leads to an order of magnitude decrease in the ignition delay time. Discharge processes and following chain chemical reactions with energy release were simulated. The generation of atoms, radicals and excited and charged particles was numerically simulated using the measured time - resolved discharge current and electric field in the discharge phase. The calculated densities of the active particles were used as input data to simulate plasma-assisted ignition. Good agreement was obtained between the calculated ignition delay times and the experimental data. It follows from the analysis of the calculated results that the main mechanism of the effect of gas discharge on the ignition of hydrocarbons is the electron impact dissociation of O2 molecules in the discharge phase. Detailed kinetic mechanism for plasma assisted ignition of hydrogen and ethene is elaborated and verified.

Global precipitation measurements for validating climate models

NASA Astrophysics Data System (ADS)

Tapiador, F. J.; Navarro, A.; Levizzani, V.; García-Ortega, E.; Huffman, G. J.; Kidd, C.; Kucera, P. A.; Kummerow, C. D.; Masunaga, H.; Petersen, W. A.; Roca, R.; Sánchez, J.-L.; Tao, W.-K.; Turk, F. J.

2017-11-01

The advent of global precipitation data sets with increasing temporal span has made it possible to use them for validating climate models. In order to fulfill the requirement of global coverage, existing products integrate satellite-derived retrievals from many sensors with direct ground observations (gauges, disdrometers, radars), which are used as reference for the satellites. While the resulting product can be deemed as the best-available source of quality validation data, awareness of the limitations of such data sets is important to avoid extracting wrong or unsubstantiated conclusions when assessing climate model abilities. This paper provides guidance on the use of precipitation data sets for climate research, including model validation and verification for improving physical parameterizations. The strengths and limitations of the data sets for climate modeling applications are presented, and a protocol for quality assurance of both observational databases and models is discussed. The paper helps elaborating the recent IPCC AR5 acknowledgment of large observational uncertainties in precipitation observations for climate model validation.

Run Environment and Data Management for Earth System Models

NASA Astrophysics Data System (ADS)

Widmann, H.; Lautenschlager, M.; Fast, I.; Legutke, S.

2009-04-01

The Integrating Model and Data Infrastructure (IMDI) developed and maintained by the Model and Data Group (M&D) comprises the Standard Compile Environment (SCE) and the Standard Run Environment (SRE). The IMDI software has a modular design, which allows to combine and couple a suite of model components and as well to execute the tasks independently and on various platforms. Furthermore the modular structure enables the extension to new model combinations and new platforms. The SRE presented here enables the configuration and performance of earth system model experiments from model integration up to storage and visualization of data. We focus on recently implemented tasks such as synchronous data base filling, graphical monitoring and automatic generation of meta data in XML forms during run time. As well we address the capability to run experiments in heterogeneous IT environments with different computing systems for model integration, data processing and storage. These features are demonstrated for model configurations and on platforms used in current or upcoming projects, e.g. MILLENNIUM or IPCC AR5.

Tracking the release of IPCC AR5 on Twitter: Users, comments, and sources following the release of the Working Group I Summary for Policymakers.

PubMed

Newman, Todd P

2017-10-01

Using the immediate release of the Working Group 1 Summary for Policymakers of the Intergovernmental Panel on Climate Change Fifth Assessment Report as a case study, this article seeks to describe what type of actors were most active during the summary release, the substance of the most propagated tweets during the summary release, and the media sources that attracted the most attention during the summary release. The results from the study suggest that non-elite actors, such as individual bloggers and concerned citizens, accounted for the majority of the most propagated tweets in the sample. This study also finds that the majority of the most propagated tweets in the sample focused on public understanding of the report. Finally, while mainstream media sources were the most frequently discussed media sources, a number of new media and science news and information sources compete for audience attention.

Dynamic EROI Assessment of the IPCC 21st Century Electricity Production Scenario

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neumeyer, Charles; Goldston, Robert

Abstract: The Energy Return on Investment (EROI) is an important measure of the energy gain of an electrical power generating facility that is typically evaluated based on the life cycle energy balance of a single facility. The EROI concept can be extended to cover a collection of facilities that comprise a complete power system and used to assess the expansion and evolution of a power system as it transitions from one portfolio mix of technologies to another over time. In this study we develop a dynamic EROI model that simulates the evolution of a power system and we perform anmore » EROI simulation of one of the electricity production scenarios developed under the auspices of the Intergovernmental Panel on Climate Change (IPCC) covering the global supply of electricity in the 21st century. Our analytic tool provides the means for evaluation of dynamic EROI based on arbitrary time-dependent demand scenarios by modeling the required expansion of power generation, including the plowback needed for new construction and to replace facilities as they are retired. The results provide insight into the level of installed and delivered power, above and beyond basic consumer demand, that is required to support construction during expansion, as well as the supplementary power that may be required if plowback constraints are imposed. In addition, sensitivity to EROI parameters, and the impact of energy storage efficiency are addressed.« less

Dynamic EROI Assessment of the IPCC 21st Century Electricity Production Scenario

DOE PAGES

Neumeyer, Charles; Goldston, Robert

2016-04-28

Abstract: The Energy Return on Investment (EROI) is an important measure of the energy gain of an electrical power generating facility that is typically evaluated based on the life cycle energy balance of a single facility. The EROI concept can be extended to cover a collection of facilities that comprise a complete power system and used to assess the expansion and evolution of a power system as it transitions from one portfolio mix of technologies to another over time. In this study we develop a dynamic EROI model that simulates the evolution of a power system and we perform anmore » EROI simulation of one of the electricity production scenarios developed under the auspices of the Intergovernmental Panel on Climate Change (IPCC) covering the global supply of electricity in the 21st century. Our analytic tool provides the means for evaluation of dynamic EROI based on arbitrary time-dependent demand scenarios by modeling the required expansion of power generation, including the plowback needed for new construction and to replace facilities as they are retired. The results provide insight into the level of installed and delivered power, above and beyond basic consumer demand, that is required to support construction during expansion, as well as the supplementary power that may be required if plowback constraints are imposed. In addition, sensitivity to EROI parameters, and the impact of energy storage efficiency are addressed.« less

(Ar-39)-(Ar-40) dating of mesosiderites - Evidence for major parent body disruption less than 4 Ga ago

NASA Technical Reports Server (NTRS)

Bogard, D. D.; Jordan, J. L.; Garrison, D. H.; Mittlefehldt, D.

1990-01-01

The (Ar-39) (Ar-40) chronologies were determined for 14 different mesosiderites representing the full range of classification according to recrystallization, and these chronologies were compared with analogous data for other meteorite types and for lunar highland rocks. Results of Ar-Ar chronologies indicate the history of a degassing of Ar due to a major thermal event that occurred less than 3.9 Ga ago; this event is not the metal-silicate mixing event, which is known to have occurred earlier than 4.4 Ga ago. It is suggested that a major collisional disruption-reassembly event less than 3.9 Ga ago took place, leaving the metal-silicate breccias buried under tens of kilometers of rubble, where they cooled slowly through the Ar closure temperatures.

Pentaarylcyclopentadienyl Iron, Cobalt, and Nickel Halides.

PubMed

Chakraborty, Uttam; Modl, Moritz; Mühldorf, Bernd; Bodensteiner, Michael; Demeshko, Serhiy; van Velzen, Niels J C; Scheer, Manfred; Harder, Sjoerd; Wolf, Robert

2016-03-21

The preparation of new stable half-sandwich transition metal complexes, having a bulky cyclopentadienyl ligand C5(C6H4-4-Et)5 (Cp(Ar1)) or C5(C6H4-4-nBu)5 (Cp(Ar2)), is reported. The tetrahydrofuran (THF) adduct [Cp(Ar1)Fe(μ-Br)(THF)]2 (1a) was synthesized by reacting K[Cp(Ar1)] with [FeBr2(THF)2] in THF, and its molecular structure was determined by X-ray crystallography. Complex 1a easily loses its coordinated THF molecules under vacuum to form the solvent-free complex [Cp(Ar1)Fe(μ-Br)]2 (1b). The analogous complexes [Cp(Ar1)Co(μ-Br)]2 (2), [Cp(Ar1)Ni(μ-Br)]2 (3), and [Cp(Ar2)Ni(μ-Br)]2 (4) were synthesized from CoBr2 and [NiBr2(1,2-dimethoxyethane)]. The mononuclear, low-spin cobalt(III) and nickel(III) complexes [Cp(Ar2)MI2] (5, M = Co; 6, M = Ni) were prepared by reacting the radical Cp(Ar2) with NiI2 and CoI2. The complexes were characterized by NMR and UV-vis spectroscopies and by elemental analyses. Single-crystal X-ray structure analyses revealed that the dimeric complexes 1a, 1b, and 3 have a planar M2Br2 core, whereas 2 and 4 feature a puckered M2Br2 ring.

Intraocular Pressure, Blood Pressure, and Retinal Blood Flow Autoregulation: A Mathematical Model to Clarify Their Relationship and Clinical Relevance

PubMed Central

Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua

2014-01-01

Purpose. This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. Methods. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. Results. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. Conclusions. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics. PMID:24876284

Intraocular pressure, blood pressure, and retinal blood flow autoregulation: a mathematical model to clarify their relationship and clinical relevance.

PubMed

Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua

2014-05-29

This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Matrix effect on vibrational frequencies: Experiments and simulations for HCl and HNgCl (Ng = Kr and Xe)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinowski, Jaroslaw; Räsänen, Markku; Lignell, Antti

2014-03-07

We study the environmental effect on molecules embedded in noble-gas (Ng) matrices. The experimental data on HXeCl and HKrCl in Ng matrices is enriched. As a result, the H−Xe stretching bands of HXeCl are now known in four Ng matrices (Ne, Ar, Kr, and Xe), and HKrCl is now known in Ar and Kr matrices. The order of the H−Xe stretching frequencies of HXeCl in different matrices is ν(Ne) < ν(Xe) < ν(Kr) < ν(Ar), which is a non-monotonous function of the dielectric constant, in contrast to the “classical” order observed for HCl: ν(Xe) < ν(Kr) < ν(Ar) < ν(Ne).more » The order of the H−Kr stretching frequencies of HKrCl is consistently ν(Kr) < ν(Ar). These matrix effects are analyzed theoretically by using a number of quantum chemical methods. The calculations on these molecules (HCl, HXeCl, and HKrCl) embedded in single Ng{sup ′} layer cages lead to very satisfactory results with respect to the relative matrix shifts in the case of the MP4(SDQ) method whereas the B3LYP-D and MP2 methods fail to fully reproduce these experimental results. The obtained order of frequencies is discussed in terms of the size available for the Ng hydrides in the cages, probably leading to different stresses on the embedded molecule. Taking into account vibrational anharmonicity produces a good agreement of the MP4(SDQ) frequencies of HCl and HXeCl with the experimental values in different matrices. This work also highlights a number of open questions in the field.« less

Identification of Novel Aldose Reductase Inhibitors from Spices: A Molecular Docking and Simulation Study.

PubMed

Antony, Priya; Vijayan, Ranjit

2015-01-01

Hyperglycemia in diabetic patients results in a diverse range of complications such as diabetic retinopathy, neuropathy, nephropathy and cardiovascular diseases. The role of aldose reductase (AR), the key enzyme in the polyol pathway, in these complications is well established. Due to notable side-effects of several drugs, phytochemicals as an alternative has gained considerable importance for the treatment of several ailments. In order to evaluate the inhibitory effects of dietary spices on AR, a collection of phytochemicals were identified from Zingiber officinale (ginger), Curcuma longa (turmeric) Allium sativum (garlic) and Trigonella foenum graecum (fenugreek). Molecular docking was performed for lead identification and molecular dynamics simulations were performed to study the dynamic behaviour of these protein-ligand interactions. Gingerenones A, B and C, lariciresinol, quercetin and calebin A from these spices exhibited high docking score, binding affinity and sustained protein-ligand interactions. Rescoring of protein ligand interactions at the end of MD simulations produced binding scores that were better than the initially docked conformations. Docking results, ligand interactions and ADMET properties of these molecules were significantly better than commercially available AR inhibitors like epalrestat, sorbinil and ranirestat. Thus, these natural molecules could be potent AR inhibitors.

Identification of Novel Aldose Reductase Inhibitors from Spices: A Molecular Docking and Simulation Study

PubMed Central

Antony, Priya; Vijayan, Ranjit

2015-01-01

Hyperglycemia in diabetic patients results in a diverse range of complications such as diabetic retinopathy, neuropathy, nephropathy and cardiovascular diseases. The role of aldose reductase (AR), the key enzyme in the polyol pathway, in these complications is well established. Due to notable side-effects of several drugs, phytochemicals as an alternative has gained considerable importance for the treatment of several ailments. In order to evaluate the inhibitory effects of dietary spices on AR, a collection of phytochemicals were identified from Zingiber officinale (ginger), Curcuma longa (turmeric) Allium sativum (garlic) and Trigonella foenum graecum (fenugreek). Molecular docking was performed for lead identification and molecular dynamics simulations were performed to study the dynamic behaviour of these protein-ligand interactions. Gingerenones A, B and C, lariciresinol, quercetin and calebin A from these spices exhibited high docking score, binding affinity and sustained protein-ligand interactions. Rescoring of protein ligand interactions at the end of MD simulations produced binding scores that were better than the initially docked conformations. Docking results, ligand interactions and ADMET properties of these molecules were significantly better than commercially available AR inhibitors like epalrestat, sorbinil and ranirestat. Thus, these natural molecules could be potent AR inhibitors. PMID:26384019

Structured Antireflective Coating for Silicon at Submillimeter Frequencies

NASA Astrophysics Data System (ADS)

Padilla, Estefania

2018-01-01

Observations at millimeter and submillimeter wavelengths are useful for many astronomical studies, such as the polarization of the cosmic microwave background or the formation and evolution of galaxy clusters. In order to allow observations over a broad spectral bandwidth (approximatively from 70 to 420 GHz), innovative broadband anti-reflective (AR) optics must be utilized in submillimeter telescopes. Due to its low loss and high refractive index, silicon is a fine optical material at these frequencies, but an AR coating with multiple layers is required to maximize its transmission over a wide bandwidth. Structured multilayer AR coatings for silicon are currently being developed at Caltech and JPL. The development process includes the design of the structured layers with commercial electromagnetic simulation software, the fabrication by using deep reactive ion etching, and the test of the transmission and reflection of the patterned wafers. Geometrical 3D patterns have successfully been etched at the surface of the silicon wafers creating up to 2 layers with different effective refractive indices. The transmission and reflection of single AR layer wafers, measured between 75 and 330 GHz, are close to the simulation predictions. These results allow the development of new designs with 5 or 6 AR layers in order to improve the bandwidth and transmission of the silicon AR coatings.

Control of βAR- and N-methyl-D-aspartate (NMDA) Receptor-Dependent cAMP Dynamics in Hippocampal Neurons

PubMed Central

Chay, Andrew; Zamparo, Ilaria; Koschinski, Andreas; Zaccolo, Manuela; Blackwell, Kim T.

2016-01-01

Norepinephrine, a neuromodulator that activates β-adrenergic receptors (βARs), facilitates learning and memory as well as the induction of synaptic plasticity in the hippocampus. Several forms of long-term potentiation (LTP) at the Schaffer collateral CA1 synapse require stimulation of both βARs and N-methyl-D-aspartate receptors (NMDARs). To understand the mechanisms mediating the interactions between βAR and NMDAR signaling pathways, we combined FRET imaging of cAMP in hippocampal neuron cultures with spatial mechanistic modeling of signaling pathways in the CA1 pyramidal neuron. Previous work implied that cAMP is synergistically produced in the presence of the βAR agonist isoproterenol and intracellular calcium. In contrast, we show that when application of isoproterenol precedes application of NMDA by several minutes, as is typical of βAR-facilitated LTP experiments, the average amplitude of the cAMP response to NMDA is attenuated compared with the response to NMDA alone. Models simulations suggest that, although the negative feedback loop formed by cAMP, cAMP-dependent protein kinase (PKA), and type 4 phosphodiesterase may be involved in attenuating the cAMP response to NMDA, it is insufficient to explain the range of experimental observations. Instead, attenuation of the cAMP response requires mechanisms upstream of adenylyl cyclase. Our model demonstrates that Gs-to-Gi switching due to PKA phosphorylation of βARs as well as Gi inhibition of type 1 adenylyl cyclase may underlie the experimental observations. This suggests that signaling by β-adrenergic receptors depends on temporal pattern of stimulation, and that switching may represent a novel mechanism for recruiting kinases involved in synaptic plasticity and memory. PMID:26901880

Ab initio based study of the ArO- photoelectron spectra: Selectivity of spin-orbit transitions

NASA Astrophysics Data System (ADS)

Buchachenko, A. A.; Jakowski, Jacek; Chałasiński, Grzegorz; Szczȩśniak, M. M.; Cybulski, S. M.

2000-04-01

A combined ab initio atoms-in-molecule approach was implemented to model the photoelectron spectra of the ArO- anion. The lowest adiabatic states of Σ and Π symmetry of ArO and ArO- were investigated using the fourth-order Møller-Plessett perturbation theory including bond functions. The total energies were dissected into electrostatic, exchange, induction, and dispersion components. The complex of Ar with atomic oxygen is only weakly bound, primarily by dispersion interaction. The Π state possesses a deeper minimum (Re=3.4Å,De=380μEh) than the Σ state (Re=3.8Å,De=220μEh). In contrast, the anion complex is fairly strongly bound, primarily by ion-induced dipole induction forces, and the Σ state possesses a deeper minimum at shorter interatomic distances (Re=3.02Å,De=3600μEh) than the Π state (Re=3.35Å,De=2400μEh). The Σ-Π splittings in both systems are mainly due to differences in the exchange repulsion terms. Atoms-in-molecule models were used to account for the spin-orbit interaction, and to generate adiabatic relativistic potentials and wave functions. Collisional properties, diffusion, and mobility coefficients of O and O- in Ar, and absolute total Ar+O scattering cross sections, were calculated and found to agree well with the available experimental data. The photoelectron spectra were simulated within vibronic model, and were found in excellent agreement with the experimental measurements. The bimodal electron kinetic energy distribution was shown to stem from the strong selectivity of spin-orbit transitions, which split into two dense groups, depending on the initial electronic state of the anion. The latter feature cannot be described without explicit consideration of electronic intensity factor.

Methane emission from ruminants and solid waste: A critical analysis of baseline and mitigation projections for climate and policy studies

NASA Astrophysics Data System (ADS)

Matthews, E.

2012-12-01

Current and projected estimates of methane (CH4) emission from anthropogenic sources are numerous but largely unexamined or compared. Presented here is a critical appraisal of CH4 projections used in climate-chemistry and policy studies. We compare emissions for major CH4 sources from several groups, including our own new data and RCP projections developed for climate-chemistry models for the next IPCC Assessment Report (AR5). We focus on current and projected baseline and mitigation emissions from ruminant animals and solid waste that are both predicted to rise dramatically in coming decades, driven primarily by developing countries. For waste, drivers include increasing urban populations, higher per capita waste generation due to economic growth and increasing landfilling rates. Analysis of a new global data base detailing waste composition, collection and disposal indicates that IPCC-based methodologies and default data overestimate CH4 emission for the current period which cascades into substantial overestimates in future projections. CH4 emission from solid waste is estimated to be ~10-15 Tg CH4/yr currently rather than the ~35 Tg/yr often reported in the literature. Moreover, emissions from developing countries are unlikely to rise rapidly in coming decades because new management approaches, such as sanitary landfills, that would increase emissions are maladapted to infrastructures in these countries and therefore unlikely to be implemented. The low current emission associated with solid waste (~10 Tg), together with future modest growth, implies that mitigation of waste-related CH4 emission is a poor candidate for slowing global warming. In the case of ruminant animals (~90 Tg CH4/yr currently), the dominant assumption driving future trajectories of CH4 emission is a substantial increase in meat and dairy consumption in developing countries to be satisfied by growing animal populations. Unlike solid waste, current ruminant emissions among studies exhibit a narrow range that does not necessarily signal low uncertainty but rather a reliance on similar animal statistics and emission factors. The UN Food and Agriculture Organization (FAO) projects 2000-2030 growth rates of livestock for most developing countries at 2% to >3% annually. However, the assumption of rapidly rising meat consumption is not supported by current trends nor by resource availability. For example, increased meat consumption in China and other developing countries is poultry and pork that do not affect CH4 emissions, suggesting that the rapid growth projected for all animals, boosting growth in CH4 emission, will not occur. From a resource standpoint, large increases in cattle, sheep and goat populations, especially for African countries (~60% by 2030), are not supportable on arid grazing lands that require very low stocking rates and semi-nomadic management. Increases projected for African animal populations would require either that about 2/3 more animals are grazed on increasingly drier lands or that all non-forested areas become grazing lands. Similar to solid waste, future methane emission from ruminant animals is likely to grow modestly although animals are not a likely candidate for CH4 mitigation due to their dispersed distribution throughout widely varying agricultural systems under very local management.

Impact of climate change on Precipitation and temperature under the RCP 8.5 and A1B scenarios in an Alpine Cathment (Alto-Genil Basin,southeast Spain). A comparison of statistical downscaling methods

NASA Astrophysics Data System (ADS)

Pulido-Velazquez, David; Juan Collados-Lara, Antonio; Pardo-Iguzquiza, Eulogio; Jimeno-Saez, Patricia; Fernandez-Chacon, Francisca

2016-04-01

In order to design adaptive strategies to global change we need to assess the future impact of climate change on water resources, which depends on precipitation and temperature series in the systems. The objective of this work is to generate future climate series in the "Alto Genil" Basin (southeast Spain) for the period 2071-2100 by perturbing the historical series using different statistical methods. For this targeted we use information coming from regionals climate model simulations (RCMs) available in two European projects, CORDEX (2013), with a spatial resolution of 12.5 km, and ENSEMBLES (2009), with a spatial resolution of 25 km. The historical climate series used for the period 1971-2000 have been obtained from Spain02 project (2012) which has the same spatial resolution that CORDEX project (both use the EURO-CORDEX grid). Two emission scenarios have been considered: the Representative Concentration Pathways (RCP) 8.5 emissions scenario, which is the most unfavorable scenario considered in the fifth Assessment Report (AR5) by the Intergovernmental Panel on Climate Change (IPCC), and the A1B emission scenario of fourth Assessment Report (AR4). We use the RCM simulations to create an ensemble of predictions weighting their information according to their ability to reproduce the main statistic of the historical climatology. A multi-objective analysis has been performed to identify which models are better in terms of goodness of fit to the cited statistic of the historical series. The ensemble of the CORDEX and the ENSEMBLES projects has been finally created with nine and four models respectively. These ensemble series have been used to assess the anomalies in mean and standard deviation (differences between the control and future RCM series). A "delta-change" method (Pulido-Velazquez et al., 2011) has been applied to define future series by modifying the historical climate series in accordance with the cited anomalies in mean and standard deviation. A comparison between results for scenario A1B and RCP8.5 has been performed. The reduction obtained for the mean rainfall respect to the historical are 24.2 % and 24.4 % respectively, and the increment in the temperature are 46.3 % and 31.2 % respectively. A sensitivity analysis of the results to the statistical downscaling techniques employed has been performed. The next techniques have been explored: Perturbation method or "delta-change"; Regression method (a regression function which relates the RCM and the historic information will be used to generate future climate series for the fixed period); Quantile mapping, (it attempts to find a transformation function which relates the observed variable and the modeled variable maintaining an statistical distribution equals the observed variable); Stochastic weather generator (SWG): They can be uni-site or multi-site (which considers the spatial correlation of climatic series). A comparative analysis of these techniques has been performed identifying the advantages and disadvantages of each of them. Acknowledgments: This research has been partially supported by the GESINHIMPADAPT project (CGL2013-48424-C2-2-R) with Spanish MINECO funds. We would also like to thank Spain02, ENSEMBLES and CORDEX projects for the data provided for this study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.

Geant4-based Monte Carlo package named G4DS has been developed to simulate the response of DarkSide-50, an experiment operating since 2013 at LNGS, designed to detect WIMP interactions in liquid argon. In the process of WIMP searches, DarkSide-50 has achieved two fundamental milestones: the rejection of electron recoil background with a power of ~10^7, using the pulse shape discrimination technique, and the measurement of the residual 39Ar contamination in underground argon, ~3 orders of magnitude lower with respect to atmospheric argon.