Influence of Land Use and Landscape Heterogeneity on Cloud Formation and Atmospheric Circulation in Southwest Australia

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Southwest Australia is an ideal test bed to investigate the influence of land use on cloud formation and atmospheric circulation patterns. Clearing of native vegetation for agricultural purposes has resulted in a 700 km long sharp boundary between the croplands and the undisturbed vegetation areas. Preliminary studies suggest that replacement of native vegetation by agricultural crops alters the surface energetics, directly influencing convective cloud formation. The drastic nature and large spatial extent of the land surface heterogeneity is conducive to the formation of secondary circulations that also impact cloud formation. This investigation will address a series of scientific questions related to the hypothesized impact on land use on cloud formation and regional atmospheric circulations of southwest Australia using a combination of ground, satellite, aircraft observations, spatial statistical analysis and numerical modeling experiments. This study will utilize these observations to characterize surface energetics and atmospheric thermodynamic structure as a function of land use and its relationship to cloud formation. Observations will also be used to verify the existence of secondary mesoscale circulations generated by landscape heterogeneity. Numerical simulations, in combination with observations, will be used to determine if differences in land use are responsible for observed variations in cloud formation and if mesoscale circulations are forced by landscape heterogeneity. Detailed analysis of satellite observed cloudiness will be conducted to determine the statistical significance of differences in cloud formation over the croplands and native vegetation This study is unique in the sense that the landscape heterogeneity has significantly higher spatial scales and exhibits drastic spatial changes. The scale and nature of the spatial heterogeneity is important since prior studies have been criticized for employing hypothetical landscape heterogeneity patterns with large spatial scales and drastic changes that have no counterparts in nature. One of the broader impacts of this study is expected to be its potential contribution towards resolving the ongoing debate on the impact of landscape heterogeneity on regional climate. The results from this study are also expected to be of utility to land use management planners experiencing drastic land use change. This research effort will enable international collaboration between researchers in United States, Australia and Japan and promote graduate education through the participation of graduate students in both the field campaign and the analysis of data generated during the project.