Wednesday, 14 January 2009: 1:45 PM
Impacts of remotely-sensed, seasonal land cover dynamics on distributed hydrological response in two forested mountain settings
Room 127B (Phoenix Convention Center)
In forested mountain watersheds, seasonal forest dynamics play an important role on hydrologic responses due to strong influences of thick and spatially extensive vegetation cover on a variety of hydrological processes. In this study, we capture the monsoon (summer) season dynamics of mountain vegetation, including its albedo and vegetative areal fraction, from remotely-sensed datasets (Landsat5 TM and MODIS) and then investigate its impact on the hydrologic responses using a distributed hydrological model. The study sites include a small basin known as the Redondo Creek (30.4 square km) and the Ponderosa pine hillslope site (870 square m) both in the Jemez Mountains, New Mexico. Our preliminary focus is on distributed hydrologic simulations for the 2005 summer monsoon period using the TIN-based Real-time Integrated Basin Simulator (tRIBS). We have modified tRIBS model to incorporate remotely-sensed vegetation parameters at prescribed temporal intervals. We investigate the impacts of vegetation dynamics by comparing the model estimates using remotely-sensed dynamic vegetation with model estimates using static vegetation. In this study, we force the tRIBS model using three precipitation products to investigate the impacts on the hydrological response for static and dynamic vegetation parameters. The rainfall forcings are gauge corrected NEXRAD observations, in-situ rainfall estimates and remotely-sensed satellite products. Our model simulations are evaluated using daily and continuous soil moisture observation at distributed sites. The preliminary results indicate that seasonal vegetation dynamics significantly alter the energy and water balance in the study sites. Furthermore, we intercompare results from the different products to assess the interrelationship of rainfall forcing and land cover change.
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