Projects in Climate Dynamics

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This project mainly covers three important research areas under the broad umbrella of climate dynamics by focusing on:a) Seasonal and year-to-year variations in the strength of the tropical upwelling in the Brewer-Dobson circulation. A major goal is to determine whether the annual cycle is forced primarily by variations in the upward flux of wave activity at high latitudes or by seasonal variations in the strength of the equatorial tropospheric planetary waves.b) 20th century climate variability. Possible foci are (i) drought episodes and/or (ii) the pronounced interdecadal variability of extratropical Northern Hemisphere temperature.c) Structure and dynamics of intermediate frequency (6-20 day period) variability and the degree to which it is dominated by linear Rossby-wave dynamics versus nonlinear processes such as wave breaking.In addition, this project will also explore preliminarily a strategy for quantitatively assessing the impact of global warming upon snowpack over the Pacific Northwest that is more robust with respect to sampling fluctuations than conventional analysis of trends in snowpack measurements. The temperature sensitivity of snowpack (i.e., the percentage loss in snowpack per °C temperature rise) is evaluated using four different approaches. This research will serve to promote more robust strategies for assessing the impacts of global warming, more useful measures of the impacts of global warming, understanding of mechanisms responsible for the secular trends in temperature and concentrations of trace constituents in the tropical lower stratosphere, a more definitive attribution of 20th century climate change, and a more sound phenomelogical basis for long range weather prediction.Broader impacts include the potential for improved weather and climate prediction and the training and mentoring of several graduate students.