Department of Atmospheric Sciences | University of Illinois

Atmospheric Sciences | Department | Colloquia

Steve Nesbitt

Assistant Professor, DAS

Date:  October 8, 2008

3:00 pm: Conversation and Cookies in Room 108 Atmospheric Sciences Building

3:30 pm: Seminar in Room 144 Loomis Lab

ABSTRACT

The North American Monsoon is a crucial life support mechanism for the American Southwest, as well as Northwest Mexico, as important to the region’s economy as it is to the region’s unique landscape and ecology.  State of the art climate model predictions, such as the models used in the 2007 Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report take the region into multi-decadal drought within the next decade, potentially devastating the region's water resources and agriculture.  However, global climate models have been shown to dubiously represent and predict many key scale-dependent monsoon physical processes, including moisture transports and convective precipitation.  Thus, better understanding of monsoon processes (including how they may be better represented in climate models) is a key challenge in quantifying uncertainties in climate predictions in the monsoon region.

This talk will provide an overview of the dynamics and precipitation characteristics of the North American Monsoon that global climate models must represent in order to robustly predict regional climate change in the region.  New satellite precipitation data products allows many facets of North American Monsoon variability to be uncovered, including variability in regions where gauges do not exist (e.g., high terrain, sparsely populated areas, ocean), and variations in precipitation on small scales (<25 km).  Comparisons of these satellite precipitation products will be made with current gauge networks.  The variability of the NAM will be investigated using these products to highlight their strengths and weaknesses. Finally, the diurnal to intraseasonal variation of the NAM will be explored within the NAM, including uncovering role of orography in setting up cloud-radiative-precipitation feedbacks in the monsoon.

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