HR: 14:10h
AN: H43I-02    [Abstracts]
TI: Impact of 300 Years of Land Cover Change on Climate
AU: Shevliakova, E
EM: elena@eno.princeton.edu
AF: Princeton University, Dept. of Ecology and Evolutionary Biology, Princeton, NJ 08542 United States
AU: * Findell, K L
EM: kirsten.findell@noaa.gov
AF: Geophysical Fluid Dynamics Lab/ NOAA, P.O. Box 308, Princeton, NJ 08542 United States
AU: Stouffer, R J
EM: ronald.stouffer@noaa.gov
AF: Geophysical Fluid Dynamics Lab/ NOAA, P.O. Box 308, Princeton, NJ 08542 United States
AU: Milly, P
EM: chris.milly@noaa.gov
AF: U.S. Geological Survey, GFDL/NOAA P.O. Box 308, Princeton, NJ 08542 United States
AB: The Geophysical Fluid Dynamics Laboratory's atmosphere/land/sea ice/mixed layer ocean model is used to investigate the impact of anthropogenic land cover changes estimated to have occurred over the past 300 years. Results of two equilibrium experiments with vegetation cover representing 1990 conditions and "natural" (~1700) conditions are compared. Land cover changes occurred over about 9% of the earth's surface, including large portions of Europe extending into Western Russia, India, Eastern China, and the Eastern United States. Smaller areas of change were in Central America, Northwestern South America, along the Guinea Coast of Africa, in much of Indonesia, and in other isolated spots around the globe. These changes were primarily conversion from native forests to agriculture or grassland. The effects of irrigation or other water management practices were not included in these experiments. The model shows that observed land cover changes have little to no significant impact on globally averaged climatic fields (e.g., 2 m air temperature is 0.008 K warmer in the simulation with 1990 land cover, net radiation at the top of the atmosphere is 0.007 W/m² lower). Field significance is not achieved in annual mean global representations of most climatic fields: for most variables, about 10% of global area passes a modified Student's t-test at the 90% significance level. Local to some of the altered regions, however, there are statistically significant changes to many climatic fields such as near-surface air temperature, evaporation, and radiative fluxes at the earth's surface. These changes are highly significant in the annual mean and in most months of the year in Eastern Europe, Eastern China, India, the Guinea Coast, and Northwestern South America, and are directly related to the local land surface changes.
DE: 1630 Impacts of global change (1225)
DE: 1632 Land cover change
DE: 1637 Regional climate change
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3337 Global climate models (1626, 4928)
SC: Hydrology [H]
MN: Fall Meeting 2005