GFDL - Geophysical Fluid Dynamics Laboratory

GFDL Research Highlights

January 23rd, 2017 - Reconciling Ocean Productivity and Fisheries Yields

The authors explore the complex relationship between phytoplankton production and fish, using recent critical advances in our knowledge of global patterns in fish catch and fishing effort, as well as the plankton food webs that connect phytoplankton and fish. A high-resolution global earth system model, developed at GFDL, was used to assess the potential magnitude of future changes in fish yield under climate change. This model has ten times the resolution of a typical climate model and includes comprehensive plankton dynamics. Read More…

September 5th, 2016 - Exploring the role of movement in determining the global distribution of marine biomass using a coupled hydrodynamic – size-based ecosystem model

Modeling the dynamics of marine populations at a global scale – from phytoplankton to fish – is necessary in order to quantify how climate change and other broad-scale anthropogenic actions affect the supply of marine-based food. In this study, the abundance and distribution of fish biomass in the ocean is estimated, by coupling a size-based fish food web model to retrospective ocean physics and biogeochemistry simulations covering the past 60 years. The authors focused on the spatial distribution of biomass, identifying highly productive regions – shelf seas, western boundary currents and major upwelling zones. Read More…

June 20th, 2016 - The North Atlantic Oscillation as a driving force for observed rapid Arctic sea ice change, hemispheric warming, and Atlantic tropical cyclone variability

In order to better understand the factors governing observed climate variability and change, it is critical to better understand the mechanisms contributing to natural climate variability, particularly on decadal and longer time scales. The ocean is thought to play a critical role in such variability. This study examined factors that influence decadal and longer time-scale variability of the Atlantic Ocean, and its subsequent influence on the overall climate system. Read More…

April 13th, 2016 - U.S. regional tornado outbreaks and their links to spring ENSO phases and North Atlantic SST variability

Tornado outbreaks are one of nature’s most destructive forces. This study breaks new ground on a potential basis for seasonal predictability of tornado outbreak probability over the U.S. in boreal spring. The goal of the study was to explore the scientific basis for predictions of outbreaks a month or more in advance. Currently, the risk of regional tornado outbreaks is predictable only about a week ahead. Read More…

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…

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