Climate Change, Variability and Prediction
We develop and use coupled ocean-atmosphere climate models to increase our understanding of climate variability and change on seasonal to centennial time scales, to assess the predictability of the climate system, and to make experimental climate predictions.
As the earth's climate continues to warm, there is concern that the characteristics of hurricanes, a phenomenon typically found over warm tropical oceans, may change. Our group seeks a better physical understanding of this issue through high resolution computer modeling studies.
Over the next decade or two the signal of climate change will be a combination of global warming and decadal variations in the climate system, including fluctuations of the Atlantic Meridional Overturning Circulation (AMOC). Here we study the mechanisms and impacts of decadal climate fluctuations, and attempt to predict the decadal scale evolution of climate.
We develop and use novel coupled data assimilation systems to produce state of the art ocean reanalyses. In addition to providing an important data set for the study of ocean changes, these reanalyses also provide initial conditions for seasonal to decadal climate predictions. These data sets are publicly available here.
El Nino is the dominant mode of climate variability on seasonal to interannual time scales. Here we pursue research to better understand and predict El Niño, including its response to global warming.
We develop and use new climate models with very high spatial resolution in both the atmospheric and oceanic components. These models provide important new insights on the climate system, and form the prototypes for future generations of climate models.
We develop and produce experimental forecasts of North Atlantic hurricane frequency
and their continued
evaluations in order to assess the performance of the system in as realistic a prediction mode as possible.
Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes
Our recent Science paper asks how the frequency of the most intense Atlantic hurricanes will change in in the current century due to human-caused climate change. It suggests that we should expect an increase in the frequency of the strongest hurricanes in the Atlantic, roughly by a factor of two by the end of the century, despite a decrease in overall number of hurricanes, but that we should not expect this trend to be clearly detectable until we near the end of the century.
For more information:
Experimental High Resolution Coupled Climate Model
Animation of daily values of sea surface temperature (SST) from an experimental high resolution coupled climate model under development at GFDL (click on figure at left to see animation). This model, named "CM2.4" has horizontal ocean resolution that varies from 25Km in the Tropics to 10 Km at high latitudes. The ocean model has 50 vertical levels, with 20 levels in the top 200 meters. The horizontal atmospheric resolution is approximately 100 KM, with 32 levels in the vertical. The model is global in domain, and has been run stably for hundreds of simulated years. The fine scale structures of many aspects of ocean circulation are clearly visible in the animation. One early result using this model is found in Farneti et al, showing the importance of oceanic mesoscale eddies in the response of the Southern Ocean to changing winds induced by climate change.
Impacts of SST on global drought and pluvial frequency
As part of the CLIVAR Drought initiative, Kirsten Findell and Thomas Delworth have helped uncover connections between North American drought and sea surface temperatures (SSTs) in the Pacific and Atlantic Oceans. Using idealized experiments with models from GFDL and four other institutions, the researchers show that both the frequency and the intensity of North American drought are highest when the eastern tropical Pacific is anomalously cold and the north Atlantic is anomalously warm, as shown in the figure below. The experiments were global in nature, allowing for similar analyses of droughts world-wide.
Findell, Kirsten L., and Thomas L Delworth, February 2010: Impact of common sea surface temperature anomalies on global drought and pluvial frequency. Journal of Climate, 23(3), 485-503. PDF