85th AMS Annual Meeting

Monday, 10 January 2005: 1:45 PM
Hydrologic sensitivity and consequences in an integrated global system model
C. Adam Schlosser, MIT, Cambridge, MA
In this study, the impact of hydrologic (i.e. precipitation) change on the global climatic, ecologic, and policy-driven economic systems is investigated. The MIT Integrated Global System Model (IGSM) is designed for simulating the global environmental changes that may arise as a result of anthropogenic causes, the uncertainties associated with the projected changes, and the effect of proposed policies on such changes. The current IGSM formulation includes an economic model for analysis of greenhouse and aerosol precursor gas emissions and mitigation proposals, models of atmospheric chemistry, climate, ocean as well as of the terrestrial biogeophysical and ecologic systems. All of these models are global and coupled but with intermediate levels of regional detail. Through the use of the IGSM, the sensitivity of these globally linked systems to imposed changes in the frequency, duration and strength of precipitation is explored. A range of probability distribution functions which determine the arrival rates and duration of precipitation events at the surface is considered. This range is constructed in such a way as to statistically reproduce the increased probability of hydrologic extremes (i.e. droughts and floods), and span a range of plausible precipitation regime changes of the global system. Analysis will be presented that characterizes the sensitivity of these imposed stochastic precipitation changes on the major components of the globally integrated model. In particular, emphasis will be placed on the impacts of these hydrologic changes to the global biogeochemical fluxes, and their subsequent feedbacks to the modeled climate system.

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