HR: 16:15h
AN: A34B-03    [Abstracts]
TI: Regional climatic impact of land use change in Southwest Australia
AU: * Nair, U S
EM: nair@nsstc.uah.edu
AF: Earth Science System Center, University of Alabama in Huntsville, 320 Sparkman Dr, Huntsville, AL 35805 United States
AU: Ray, D K
EM: ray@nsstc.uah.edu
AF: Department of Atmospheric Sceice, University of Alabama in Huntsville, 320 Sparkman Dr, Huntsville, AL 35805 United States
AU: Welch, R M
EM: welch@nsstc.uah.edu
AF: Department of Atmospheric Sceice, University of Alabama in Huntsville, 320 Sparkman Dr, Huntsville, AL 35805 United States
AU: Lyons, T J
EM: lyons@essun1.murdoch.edu.au
AF: Environmental Science, Murdoch University, Murdoch, W.A 6150 Australia
AB: Southwest Australia is a site of drastic land use change, with an estimated 13 million hectares of native vegetation been removed for agricultural purposes. A 750 km rabbit proof fence marks the boundary between the croplands along the Southwest coast and the native vegetation in the continental interior. Due to the high contrast in albedo between the two land use types, the boundary separating these areas is a prominent feature in the satellite images for this region. A 20 precent decrease in rainfall has been observed in the agricultural region; satellite data analysis shows differences in cloud formation and development between the native vegetation and agricultural areas. The remotely sensed Clouds and Earth's Radiant Energy System (CERES) data is used to examine the seasonal variations in the clear sky radiative components of surface energy budget over agricultural and native vegetation areas. The net shortwave flux at the surface is consistently higher throughout the year over native vegetation areas compared to agricultural areas. The maximum difference in the net shortwave flux of approximately 150 Wm-2 occurs during the months of December-January when the agricultural areas are bare after harvest. The difference in net shortwave between the two land use types decreases steadily until August, the peak of the growing season, reaching an average value of approximately 25 Wm-2, after which it remains relatively constant until November. The net longwave flux at the surface is consistently lower over the agricultural areas throughout most of the year except during the months of September-November, when it is approximately the same over both land use types. The maximum difference in net longwave flux of 20Wm-2 occurs during the month of February, with a gradual decrease until September. The differences in radiative components of the surface energy budget, along with varied transpirational characteristics of the vegetation, are responsible for observed differences in cloud formation between the two land use types. Other potential regional climatic impacts, including the alteration of regional circulation patterns, will be discussed.
DE: 3307 Boundary layer processes
DE: 3322 Land/atmosphere interactions
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly