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…
GFDL Research Highlights
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…
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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Extreme seasonal/annual precipitation, defined here as ranking first, second, or third highest or lowest in the record of at least 100 years, occurred in several continental U.S. regions during 2013. The authors of this study used CMIP5 models to simulate internal climate variability and the response to historical anthropogenic and natural forcings, for the Northern Tier and the Upper Midwest regions of the U.S. This study suggests that, for these two regions, extreme annual or seasonal positive precipitation anomalies over the U.S. were at least partly attributable to a combination of anthropogenic and natural forcing.
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In order to produce better seasonal-to-interannual climate predictions, GFDL scientists explored improvements in the method of initializing a high-resolution coupled model. Traditionally, when observations are assimilated into a high-resolution coupled model, small-scale cyclones tend to get filtered out in the process of making corrections to the large-scale background. GFDL scientists pioneered a method of processing the large-scale background and the small-scale perturbations separately in a cyclone-permitting model.
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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.
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August 13th, 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.
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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. The projected sub-surface warming is twice as large as previously estimated, on average, and it affects almost all of coastal Antarctica. This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica. It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise.
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