88th Annual Meeting (20-24 January 2008)

Wednesday, 23 January 2008: 11:15 AM
Impact of land use change on the evolution of convective boundary layer
220 (Ernest N. Morial Convention Center)
Yuling Wu, Univ. of Alabama, Huntsville, AL; and U. U. Nair, T. J. Lyons, J. Hacker, R. M. Welch, and R. A. Pielke Sr.
A series of field campaigns (Bunny Fence Experiment, BUFEX) have been conducted in Southwest Australia to investigate the influence of land use modification on the observed changes in atmospheric processes, such as dust devil occurrence, sea breeze circulation, and cloud formation. The analysis of the data collected during the first phase of the field campaigns, conducted during December of 2005, shows that there exists differential thermodynamic properties, energy fluxes, and boundary layer evolution between native vegetation and agricultural areas in the region. Model simulation of five BUFEX days yielded results in agreement with the analysis, suggesting that the removal of native vegetation is responsible for energy fluxes redistribution and change in boundary layer evolution that are likely to have contributed to the observed changes of the atmospheric processes in the region. Using large eddy simulation, sensitivity tests were conducted on surface characteristics of soil moisture, vegetation coverage, and vegetation albedo to quantify the land use effects on the planetary boundary layer to provide further insight of the land-atmosphere interaction. The results show how these surface characteristics alter the boundary layer evolution via changing the surface energy budget balanced by radiation, surface heat fluxes, and ground flux.

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