89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009: 2:00 PM
Impact of Land Cover Land Use Changes on a Sea Breeze Dominated Climate in the Tropics
Room 126A (Phoenix Convention Center)
Daniel E. Comarazamy, Santa Clara University, New York, NY; and J. E. Gonzalez and E. Harmsen
The overall goal of this project is to gain a better understanding of the climate and hydrological cycle of a tropical sea breeze dominated regional climate. The location of interest is the western coast of the island of Puerto Rico, located in the eastern edge of the Caribbean Basin. The regional climate of the area is controlled by the interaction of the westerly sea breeze with the easterly warm and humid air masses from the trade winds. This convergence is the main source of local precipitation events and rainfall. Changes in land use may influence the variability and intensity of this process. To address the analysis, the team of researchers has made use of integrated information from remote sensors, numerical models, and observational data. The Regional Atmospheric Modeling system (RAMS) has been coupled with remote sensing data and GIS digital maps to update the model's surface characteristics, and the results have been validated with ground sensors and gauge data. The atmospheric model highest resolution grid size is 1km and has been tested separately for the study region. The land use configuration for this study consists of two scenarios: the current conditions are provided by the USGS 1992-93 LCLU data, and the past conditions represented by digitalized maps of LCLU for 1951. The research focuses on the impact that these land use scenarios may have on temperature, precipitation, and the land/sea breeze circulation, which produces afternoon clouds over MayagŁez with its associated rain showers. Of interest is the development of a threshold of trade wind intensity and direction that allows a sea breeze regime to dominate the climate and weather of the area of interest. The preliminary control simulations (performed with the current LCLU specifications) show a sea breeze penetrating an average of 50km at variable intensity. The sea breeze front then encounters the eastern hills, which provide an extra lifting mechanism to enhance convection and produce the observed afternoon showers in the western coast of Puerto Rico. These preliminary simulations produced a monthly accumulated precipitation of ~30mm for January 2007 (dry season), and ~125mm in August 2007 (late rainfall season), both values compared very well with the total recorded by the rain gauges located in the region.

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