HR: 15:20h
AN: H43I-07    [Abstracts]
TI: Impacts of Remotely-Sensed Vegetation Dynamics on Ecohydrological Response in a Small Mountainous Watershed
AU: * MAHMOOD, T H
EM: tmahmood@nmt.edu
AF: Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, 801 Leroy Pl, Socorro, NM 87801, United States
AU: Vivoni, E R
EM: vivoni@nmt.edu
AF: Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, 801 Leroy Pl, Socorro, NM 87801, United States
AB: In forested mountain watersheds, the vegetation dynamics may play an important role in the seasonal distributed hydrologic response. For example, the seasonal dynamics of plant albedo and leaf area would affect the energy and mass balances in the hydrologic system through incoming radiation and rainfall interception. In this study, we attempt to capture the seasonal variations in mountain vegetation, including its albedo and areal fraction, from remotely-sensed datasets and then investigate its impact on the predictions of a distributed hydrological model. The study site is a small mountainous basin known as the Redondo Creek of the Valles Calderas National Preserve, New Mexico. Our initial focus is on distributed simulations of the 2005 summer monsoon period using the TIN-based Real-time Integrated Basin Simulator (tRIBS). We have modified tRIBS to incorporate remotely sensed vegetation parameters at prescribed temporal intervals. The vegetation observations are derived from two sensors: (1) fine spatial resolution Landsat 5 TM at 16-day intervals, and (2) is coarse spatial resolution MODIS composites at 8-day intervals. To force the distributed hydrologic model during the monsoon period, we utilize in- situ hydrometeorological forcing from a nearby weather station and gauge-corrected NEXRAD radar observations. Our model results are compared against the observed daily soil moisture obtained at a network of sites during late July of 2005 and the hourly soil moisture estimates at the weather station. We also assess model performance at a particular site relative to transpiration observations using the sapflow method. The model results using the dynamic vegetation are compared with a temporally static vegetation case to reveal the impacts of seasonal dynamics. Our study points to the importance of capturing spatiotemporal vegetation dynamics in hydrological simulations of forested ecosystems.
DE: 1800 HYDROLOGY
DE: 1813 Eco-hydrology
SC: Hydrology [H]
MN: 2007 Fall Meeting