GFDL - Geophysical Fluid Dynamics Laboratory

GFDL Research Highlights

February 22nd, 2016 - Anthropogenic climate change drives shift and shuffle in North Atlantic phytoplankton communities

This study estimates the impact of projected anthropogenic climate change over the next century on marine phytoplankton communities, and increases our understanding of the environmental drivers of ecological change. The change in biogeography for North Atlantic phytoplankton taxa in response to anthropogenic climate change is quantified, and the primary physical drivers of the projected changes are diagnosed. These findings indicate that over the course of the next century, climate change may significantly modify phytoplankton assemblages throughout the North Atlantic, and may shift individual species ranges considerably, on a magnitude of the exclusive economic zones for the marine territory of many countries. Read More…

February 1st, 2016 - Enhanced Atlantic Sea Level Rise Relative to the Pacific Under High Carbon Emission Rates

Recent observational studies indicate that more than 90% of the anthropogenically-generated heat anomaly generated between 1971 and 2010 has gone into warming the oceans. Furthermore, the Atlantic basin is warming faster than the Pacific. This study demonstrates that basin scale differences in heat uptake and sea level rise are a forced response from increasing atmospheric carbon dioxide concentrations, and the inter-basin differences vary with emission rate (see figure). Weaker overturning circulations in the Atlantic in the higher emission scenarios (i.e. > 5 GtC yr-1) make the ocean interior both warmer and less ventilated and are associated with enhanced Atlantic sea level rise, relative to the Pacific. The basin scale differences in sea level rise that vary with emission rate are relevant to climate adaptation efforts because they illustrate the relative vulnerability of the Atlantic to high emission rates and demonstrate that global average metrics of sea level rise could become less representative of regional scale changes. Read More…

January 8th, 2016 - Enhanced warming of the Northwest Atlantic Ocean under climate change

The Intergovernmental Panel on Climate Change (IPCC) fifth assessment of projected global and regional ocean temperature change is based on global climate models that have coarse (~100-km) ocean and atmosphere resolutions. In the Northwest Atlantic, the ensemble of global climate models has a warm bias in sea surface temperature due to a misrepresentation of the Gulf Stream position; thus, existing climate change projections are based on unrealistic regional ocean circulation. Read More…

May 12th, 2015 - Climate variability modulates Western U.S. ozone air quality in spring via deep stratospheric intrusions

Exposure to ground-level ozone is associated with numerous effects on human health. It can also have harmful effects on sensitive vegetation and ecosystems. There is mounting evidence that deep stratospheric intrusions (when “good” ozone is forced from the stratosphere into the troposphere by strong winds) can elevate surface ozone to unhealthy levels at high-elevation western U.S. regions during spring. This study demonstrates a link between strong La Niña winters and late spring stratospheric intrusions in the western Rockies. This link is important for developing seasonal forecasts a few months in advance, to aid in western U.S. air quality planning and for effective implementation of U.S. ozone standards. Read More…

April 7th, 2015 - Mechanisms for Low Frequency Variability of Summer Arctic Sea Ice Extent

Satellite observations reveal a substantial decline in September Arctic sea ice extent (SIE) since 1979. The exact mechanisms causing this rapid decline are still unclear. The goals of this research are to provide a fundamental understanding of low frequency variability of summer Arctic sea ice extent, and the implications for the observed decline in summer Arctic sea ice in recent decades. A multiple regression model was developed to quantify the relative contributions of three key predictors on the low frequency variability of summer Arctic sea ice extent: Atlantic heat transport into the Arctic, Pacific heat transport into the Arctic, and Arctic Dipole. A 3,600 year segment of the GFDL’s CM2.1 global climate model control simulation was employed to develop this multiple regression model. Read More…

March 23rd, 2015 - Understanding ENSO Diversity

The El Niño / Southern Oscillation (ENSO) is Earth’s strongest interannual climate fluctuation, impacting weather, ecosystems, and economies around the world. Understanding the range of ENSO variation could help lead to longer range predictions of El Niño and La Niña events. The authors review the current state of understanding of diversity among different El Niño / Southern Oscillation (ENSO) events, which differ from event to event in their amplitude, spatial pattern, temporal evolution, dynamical mechanisms, and impacts. Read More…

March 13th, 2015 - A link between the hiatus in global warming and North American drought

The authors use three GFDL climate models (CM2.1, CM2.5_FLOR, CM2.5_FLOR_FA) to study the mechanisms behind the hiatus in global warming over the last decade and their possible relationship to southwestern U.S. drought. This study suggests that a majority of the drought in the southwestern U.S. over the last decade is the result of persistent anomalous wind conditions in the tropical Pacific, and is likely due to natural variability. Read More…

March 6th, 2015 - Improved Seasonal Prediction of Temperature and Precipitation over Land in a High-resolution GFDL Climate Model

Skillful seasonal predictions of surface temperature and precipitation over land are in demand, due to their importance to ecosystems and sectors such as agriculture, energy, transportation. This study demonstrates skillful seasonal prediction of near-surface air temperature and precipitation over land using a new high-resolution climate model developed at GFDL, called FLOR. The study also diagnoses the sources of the prediction skill. Read More…

February 24th, 2015 - An Extreme Event of Sea-level Rise along the Northeast Coast of North America in 2009–2010

Coastal sea levels along continental margins often show significant year-to-year upward and downward fluctuations. These fluctuations are superimposed on a longer term upward trend associated with the rise in global mean sea level, with global mean sea level rising at roughly 3 mm per year during the recent 20 years of accurate satellite measures. For society, it is the regional changes along any particular coastal zone that are most important. Our analysis of multi-decadal tide gauge records along the North American east coast identified an extreme sea-level rise event during 2009–2010. Within this relatively brief two-year period, coastal sea level north of New York City jumped by up to 128 mm. This magnitude of inter-annual sea level rise is unprecedented in the tide gauge records, with statistical methods suggesting that it was a 1-in-850 year event.
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February 5th, 2015 - Tropical Climate Change Control of the Lower Stratospheric Circulation

Tropical air has less ozone than polar air, even though the tropical stratosphere is where most atmospheric ozone is produced. The Brewer-Dobson circulation is considered key to understanding this apparent contrast. It also brings water vapor, aerosols and other species from the troposphere up into the stratosphere. The strength of the Brewer-Dobson circulation directly affects the thermal structure of the stratosphere and upper troposphere, and impacts the transport and distribution of important climate-influencing constituents including stratospheric water vapor, ozone, and volcanic aerosols. Read More…

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