HR: 0800h
AN: H41D-0432    [Abstracts]
TI: Weak Simulated Extratropical Responses to Tropical Deforestation
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: Knutson, T R
EM: tom.knutson@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 AM2/LM2 version of the Geophysical Fluid Dynamics Laboratory's atmosphere/land model coupled to a slab ocean model has been used to investigate remote responses to tropical deforestation. Magnitudes and significance of differences between a control run and a deforested run are assessed through comparisons of 50-year time series, accounting for autocorrelation and field significance. Complete conversion of the broadleaf evergreen forests of South America, central Africa, and the islands of Oceania to grasslands leads to highly significant local responses. In addition, a broad but mild warming is seen throughout the tropical troposphere (< 0.2 °C between 700 and 150 mb), significant in northern spring and summer. However, the simulation results show very little statistically significant response beyond the tropics. There are no significant differences in any hydroclimatic variables (e.g., precipitation, soil moisture, evaporation) in either the northern or the southern extratropics. Small but statistically significant local differences in some geopotential height and wind fields are present in the southeastern Pacific Ocean. Use of the same statistical tests on two 50-year segments of the control run show that the small but significant extratropical differences between the deforested run and the control run are similar in magnitude and area to the differences between non-overlapping segments of the control run. These simulations suggest that on the time scale of 50 years, extratropical responses to complete tropical deforestation are unlikely to be distinguishable from natural climate variability.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1632 Land cover change
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3337 Global climate models (1626, 4928)
SC: Hydrology [H]
MN: Fall Meeting 2005