Winter Shrinking by Seven Days Each Decade
Climate trends in the northeastern U.S. show that in the past 40 years, winter has lost seven days every decade and the growing season has expanded by nearly four days each decade.
The warming climate and changing seasons affect farmers, foresters, outdoor recreation and wildlife, and society at large. Understanding these changes on a local level enables policymakers and others to adapt to the changes.
Seasonal climate has a natural variability from year to year. However, in recent decades Vermont’s climate has changed rapidly, with winter temperatures rising twice as fast as summer temperatures. The cold season is shrinking by one week every decade. As snow and ice cover decreases, less sunlight is reflected, which accelerates winter warming. The summer growing season-the time between the last spring frost and the first fall frost–is adding one week every two decades. For every degree (Fahrenheit) increase in temperature in late winter and early spring, leaf-out and bloom come earlier by two to three days.
Considerable progress has been made in evaluating the present generation of global models and reanalyses, but there are still deficiencies in their physical parameterizations, particularly in the modeling of energy and water transports at the land surface, and in the coupling of the surface and boundary layer to clouds and precipitation. This research advances the understanding of the interactions between the land surface fluxes of energy, water and carbon dioxide with clouds and precipitation, in support of global analysis and modeling of the earth’s land-atmosphere system.
Intellectual merit: The PI will (1) analyze flux tower datasets, examine their use for evaluating the representation of physical processes in global models, and evaluate global reanalyses on river basin scales, and (2) develop idealized models for the atmospheric boundary layer.
Broader Impacts: The research will improve medium-range and seasonal weather forecasting, and quantify the component of the surface CO2 budget associated with natural vegetation.