HR: 12:05h
AN: PP52A-08    [Abstracts]
TI: Using Model Simulations to Improve Interpretations of Paleoclimate Variability and Estimates of Vegetation Response to Potential Future Drought
AU: * Shafer, S L
EM: sshafer@usgs.gov
AF: U.S. Geological Survey, 200 SW 35th St., Corvallis, OR 97333 United States
AU: Bartlein, P J
EM: bartlein@uoregon.edu
AF: Dept. of Geography, Univ. of Oregon, 1251 Univ. of Oregon, Eugene, OR 97403 United States
AB: Future climate change will involve not just changes in the mean state of the climate but also changes in climate variability and the frequency of extreme climate events. How will modern ecosystems respond to these future climate changes? Paleoenvironmental data provide an important record of past environmental response to changes in climate variability. Often, however, paleoenvironmental records do not have a sufficient temporal resolution to indicate whether an observed environmental change was due to variations in the magnitude, frequency, or duration of a particular climate change. For example, pollen records from lakes may record a vegetation shift indicating that a drought occurred at a particular time in the past, but they may not have the temporal resolution to indicate whether the observed vegetation response was the result of one large multi-year drought or frequent annual-scale droughts occurring over a period of decades. In this study we use models to simulate vegetation response to drought under a range of climate variability scenarios. We focus on drought events because they are frequently recorded in paleoenvironmental data and because the potential impacts of droughts under future climate are of particular societal concern. We use climate data from the Climate Research Unit (East Anglia, UK) 30-minute CL 2.0 data set (New et al. 2002) and the Tyndall Centre (East Anglia, UK) 30-minute TS 2.0 data set (Mitchell et al. 2003). Our climate variability scenarios include changes in the frequency, magnitude, and duration of drought events on intra-annual, inter-annual, and decadal time scales. Vegetation responses to these changes in climate variability are simulated using LPJ, a dynamic global vegetation model (Sitch et al. 2003). We focus on simulations of woodlands and grassland-forest boundaries in North America because these vegetation types are particularly responsive to changes in moisture regime, such as drought. The results of this study indicate how model experiments can be used to improve both interpretations of paleoenvironmental data and estimations of the potential environmental impacts of future changes in climate variability.
DE: 9350 North America
DE: 3344 Paleoclimatology
DE: 1812 Drought
DE: 1851 Plant ecology
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting