87th AMS Annual Meeting

Monday, 15 January 2007
Impact of land use change on the boundary layer development and cloud formation in Southwest Australia
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Salvi AsefiNajafabady, University of Alabama in Huntsville, Huntsville, AL; and Y. Wu, U. S. Nair, R. A. Pielke Sr., T. J. Lyons, J. Hacker, and R. M. Welch
Southwest Australia has experienced significant changes in land use in the recent decades with areas in excess of 13 million hectares being cleared for agricultural purposes. The Rabbit Proof Fence, approximately 750 km long, separates the croplands to the west from the native vegetation to the east. Winter growing agricultural crops have consistently higher albedo and transpire freely compared to the native vegetation consisting of mallee woodlands dominated by eucalyptus. Satellite imagery over this area show indications that cloud formation may be significantly influenced by land use. Boundary layer clouds often form preferentially over the native vegetation areas and at times the cloud fields over the native vegetation areas terminate at the Fence.

Recently a field experiment, BuFex-05, was conducted in this area with the aim of understanding this phenomenon. A variety of measurement, including radiosondes, aircraft observations and surface energy flux and meteorological measurements were made during this field campaign. A series of Large Eddy Simulation experiments, using the Regional Atmospheric Modeling System, is being conducted to understand the physical processes responsible for differences in cloud formation between the agricultural and native vegetation areas. Results from the numerical modeling experiments and comparison observations will be presented.

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