HR: 16:15h
AN: A34A-03 INVITED     [Abstracts]
TI: Impact of Surface Changes on US Temperature Trends: Seasonal Cycle
AU: * Kalnay, E
EM: ekalnay@atmos.umd.edu
AF: Department of Meteorology University of Maryland, 3431 CSS Bdg, Greenbelt, MD 20742 United States
AU: Li, H
EM: lhhelen@atmos.umd.edu
AF: Department of Meteorology University of Maryland, 3431 CSS Bdg, Greenbelt, MD 20742 United States
AU: Cai, M
EM: cai@met.fsu.edu
AF: Department of Meteorology Florida State University, 404 Love Bdg, Tallahassee, FL 32306 United States
AB: Kalnay and Cai (Nature, 2003) proposed a method to identify the impact of surface changes as the difference between the trends of the surface observations (which reflect all the sources of climate forcing, including surface effects) and the NCEP-NCAR Reanalysis (which only contains forcings that influence the assimilated atmospheric temperature trends). This difference would include not only urbanization effects but also changes in agricultural practices, such as irrigation and deforestation, and any other changes not included in the Reanalysis and should depend on the land type. We slightly correct previous results by excluding West Coast stations. Since the estimated land-use changes impact increases the minimum temperature and decreases the maximum temperature, the impact on the mean temperature is small and geographically similar to the nightlight estimate of Hansen et al (2001), but the impact on the diurnal temperature range is large. The seasonal cycle shows that the impact of the greenhouse gases trends dominates in the winter, whereas the apparent impact of land-use changes is larger in the summer. The impact of the NCDC station corrections on the estimates is also discussed.
DE: 0399 General or miscellaneous
DE: 1600 GLOBAL CHANGE (New category)
DE: 1610 Atmosphere (0315, 0325)
DE: 1699 General or miscellaneous
DE: 9350 North America
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly