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…
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…
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…
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…
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…
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…
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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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…
Earth System Models (ESMs) project that climate change will lead to approximately 1-10% declines in global ocean phytoplankton productivity by the end of the 21st century, under high carbon emissions scenarios. This decline results from projected increases in ocean stratification under global warming, which hinders the supply of deep ocean nutrients to the well-lit surface ocean.
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The high mountains of Asia, including the Karakoram, Himalayas, and Tibetan Plateau, combine to form a region of perplexing hydroclimate changes. Glaciers in the Karakoram region have exhibited mass stability or even expansion, contrasting with glacial mass loss across the nearby Himalayas and Tibetan Plateau. This suggests that different regional snowfall or temperature signals might be detected in the Karakoram region. However, the remote location, complex terrain, and multi-country fabric of high-mountain Asia have made it difficult to maintain longer-term monitoring systems of the meteorological components that can influence glacial change.
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