GFDL - Geophysical Fluid Dynamics Laboratory

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GFDL Research Highlights

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August 22, 2014 - Predicting a decadal shift in North Atlantic climate variability using the GFDL forecast system
The goals of this research were to assess the role of AMOC in global climate and identify the predictability of the associated climate impacts. Decadal prediction experiments were conducted as part of CMIP5 using a prototype GFDL-CM2.1 forecast system. The abrupt warming of the North Atlantic subpolar gyre (SPG), observed in the mid-1990s, was used as a case study to evaluate the forecast capabilities of the model, and to better understand the reasons for the observed changes. Read more...

August 13, 2014 - Seasonal Forecasting of Regional Tropical Cyclone Activity
Tropical cyclones (TCs, which include hurricanes and typhoons) are a major climate hazard across the Northern Hemisphere, and have exhibited variability and change on year-to-year timescales. Understanding and predicting future year-to-year TC activity is central to NOAA's mission and highly relevant to society. Of particular relevance for decision support is predicting seasonal activity on regional spatial scales (scales smaller than the entire basin) – a goal that has remained elusive. Read more...

July 21, 2014 - Rapid subsurface warming and circulation changes of Antarctic coastal waters by poleward shifting winds
Projected changes in the winds circling the Antarctic may accelerate global sea level rise significantly more than previously estimated. Changes to Antarctic winds may have a profound impact on warming ocean temperatures under the ice shelves along the coastline of West and East Antarctic. Projected Antarctic wind shifts were included in a detailed global ocean model, and the authors found water up to 4°C warmer than current temperatures rose up to meet the base of the Antarctic ice shelves. Read more...

July 13, 2014 - Regional rainfall decline in Australia attributed to anthropogenic greenhouse gases and ozone levels
A suite of simulations, with a new high-resolution climate model (CM2.5) developed at GFDL, were used to study the observed long-term decline of winter rainfall over parts of southern Australia. In addition to a control simulation, ensembles of simulations were performed that included various combinations of changing radiative forcing, including those from natural sources (volcanic eruptions and solar irradiance changes) and anthropogenic sources (changes in greenhouse gases, aerosols, ozone, and land use changes). Read more...

June 26, 2014 - Trajectory sensitivity of the transient climate response to cumulative carbon emission
The insensitivity of the global climate response once emissions cease in simplified coupled climate models has been used to argue for lack of committed warming based on past carbon emissions. Additional studies have also demonstrated that the cessation of carbon emissions results in a stabilization or decrease of global mean surface air temperature. Such studies generally assume either a 1%/year increase or an instantaneous doubling/quadrupling of atmospheric CO2. Read more...

May 23, 2014 - The Role of Global Climate Change in the Extreme Low Summer Arctic Sea Ice Extent in 2012
The rapid change in summer Arctic sea ice could have significant large scale climatic, ecological, and economic impacts. Understanding the mechanisms for the recent rapid decline in summer Arctic sea ice will help to predict future changes in summer Arctic sea ice and associated climatic, ecological, and economic impacts. Read more...

May 14, 2014 - The Poleward Migration of the Location of Tropical Cyclone Maximum Intensity
Tropical cyclones (TCs), including hurricanes and typhoons, are a major hazard around the globe, including North America. TCs have exhibited variability and change on a variety of timescales, including multi-decadal changes. Scientists used a novel method to measure changes in TC activity over the past 30 years: the location at which a tropical cyclone achieves its lifetime-maximum intensity (or LMI). Over the past 30 years the typical location of LMI has moved poleward in both hemispheres – at a rate of over 30 miles per decade. Read more...

May 7, 2014 - Contribution of Local and Remote Anthropogenic Aerosols to the 20th century Weakening of the South Asian Monsoon
The impact of the late 20th century changes of anthropogenic aerosols from local (i.e., South Asia) and remote (i.e., outside South Asia) sources on the South Asian summer monsoon is a rather unexplored topic. It has important implications for strategies to control regional pollution and understand its effect in climate. GFDL scientists investigated the impact of this change in aerosols on the South Asian monsoon. This work provides new insights into the pathway by which global anthropogenic aerosols affect long-term variations of the monsoon hydroclimate, which is still uncertain and largely debated in the scientific community. Read more...

February 14, 2014 - Changing Ocean may Challenge Atlantic Cod
This study uses climate projections from GFDL’s Earth system model (ESM2.1) to force an individual-based model for the larval stages of North Atlantic Cod at each of 5 cod spawning sites across the North Atlantic. The behavioral and physiological state of thousands of cod larvae is modeled in response to ESM projected physical and biological changes. The ESM-IBM coupling provides a unique means of exploring the mechanistic response of cod larvae to climate forcing. Read more...

February 6, 2014 - Solving the mystery of Hawaiian ozone changes
A potent greenhouse gas and biological irritant, ozone near the Earth surface is also a health-damaging air pollutant, regulated by the U.S. Environmental Protection Agency. Climate shifts have caused Asian ozone pollution reaching Hawaii to rise unexpectedly in autumn since mid-1990s, according to this study. The findings, published in Nature Geoscience, imply that variability in airflow patterns must be considered when attributing observed ozone changes to human-induced trends in precursor emissions. Read more...

January 28, 2014 - Regular patterns in frictional resistance of ice-stream beds seen by surface data inversion
This study advances our understanding of the physical processes controlling the dynamics of ice streams - pathways for ice discharge from the interior of ice sheets to surrounding oceans - and the leading source of uncertainty in projections of global sea level rise in the 21st century. Read more...

September 18, 2013 - The Extreme March-May 2012 Warm Anomaly Over the Eastern United States: Global Context and Multimodel Trend Analysis
The authors compared observations to model results, using 23 different CMIP5 models to simulate internal climate variability and the response to anthropogenic and natural forcing. The models were used to investigate the causes of the unusual warmth during March-May 2012 that occurred over the eastern U.S. The 20th century warming trend that was observed in this region is consistent with the CMIP5 multi-model ensemble results of All-Forcing runs but not consistent with model runs that did not include external forcing. Read more...

September 10, 2013 - Global-scale carbon and energy flows through the planktonic food web: an analysis with a coupled physical-biological model
Planktonic food web dynamics shape biogeochemical cycles and global patterns of ocean productivity across trophic levels. Primary production alone, for example, is a poor predictor of cross-ecosystem differences in fisheries yields. Predictive capability improves only after consideration of factors such as the number and efficiency of trophic links separating phytoplankton and fish. Limited representation and validation of planktonic food web dynamics within the present generation of Earth System Models limits both their resolution of biogeochemical processes and their utility for assessing climate impacts on living marine resources. Read more...

August 30, 2013 - Multi-Model Assessment of Regional Surface Temperature Trends: CMIP3 and CMIP5 20th Century Simulations
Evaluating climate simulations against observational data is a fundamental step in the evaluation and eventual improvement of models. Models can also help test our understanding of the causes of past variations of climate seen in the historical record. This analysis shows how current climate models, including those developed by NOAA, compare with observations in terms of their regional surface temperature trends since 1901. Read more...

August 19, 2013 - Model Projections of the Changes in Atmospheric Circulation and Surface Climate over North America, North Atlantic and Europe in the 21st Century
The impacts of climate change on the North America-North Atlantic-Europe sector are studied using a coupled general circulation model (CM3) and a high-resolution atmosphere-only model (HIRAM), both developed at the Geophysical Fluid Dynamics Laboratory. Long-term changes in surface temperature, precipitation and storminess patterns over Europe and the North Atlantic are projected. Read more...

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