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United States Department of Agriculture (USDA) 2010

REMOTELY-SENSED OBSERVATIONS OF WATER AVAILABILITY AND DROUGHT SUSCEPTIBILITY IN THE SOUTHWEST

Remote Sensing Water Drought

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : REMOTELY-SENSED OBSERVATIONS OF WATER AVAILABILITY AND DROUGHT SUSCEPTIBILITY IN THE SOUTHWEST

Identification : ARZT-136749-H-21-149

Pays : Etats Unis

Durée : Oct 1, 2009 à Dec 31, 2010

Domaine : remote sensing ; arid lands ; modis ; trmm ; productivity ; water use efficiency ; plant growth ; ecosystems ; global change ; climate variability

Partenaire : UNIVERSITY OF ARIZONA TUCSON,AZ 85721

Objectifs
In this project, our goal is to examine patterns of remote sensing phenologic variability across the arid and semiarid ecosystems of the southwest U.S. and northwest Mexico using space-borne fine resolution and moderate resolution satellite measurements. Moderate resolution satellite data provide high frequency but poor spatial resolution data of limited spectral content, while fine resolution satellite data offer improved spectral detail but at infrequent time intervals. We will focus on satellite data fusion methods and scaling methods for improved characterization of landscape seasonality, gross primary production, and vegetation responses to climate variability, including drought. We plan to examine how land cover modifications and land conversions alter vegetation responses to rainfall and the resulting consequences on land surface runoff, water storage, ecosystem health and drought vulnerability. The primary objectives of this study are to use satellite data sets to (1) quantify and map the spatial and temporal patterns of landscape phenology and primary production sensitivity to precipitation and soil water availability across the range of land cover conditions found in the Southwest region ; (2) spatially map precipitation use efficiency (PUE = production/ precipitation) relationships to identify potential mechanisms (e.g. soil water holding capacity) underlying variation in ecosystem sensitivity to precipitation ; and (3) evaluate the interannual variations in phenology and PUE with remotely-sensed satellite observations in order to improve the prediction of vegetation responses to climate change and/ or human land cover modifications. This will provide valuable and timely information on overall water use in arid land ecosystems. Specific questions we plan to address include the determination of precipitation use efficiencies (PUE) and interannual variations of the dominant land cover types and ecosystems in the Southwest ; assess how PUE and surface hydrology (runoff, soil water storage) are inter-related at the landscape scale ; determine how land cover modifications and land conversions alter land surface hydrology, productivity, and PUE and the consequences to land surface runoff and water storage ; assess the relative importance and magnitude of vegetational (physiognomy, phenology) and environmental constraints (biogeochemical, soil type, topography, temperature) on PUE/ WUE and surface hydrology ; and study how PUE and surface hydrology are related to ecosystem health, phenology, drought indices, and land degradation. The expected outcomes include (a) mapping patterns of change in the spatial and temporal sensitivity of productivity to annual precipitation,(b)identify sites and areas of greatest vulnerability to drought and sensitivity to climate change, (c) assessment of impacts of land cover modifications on water availability, and (d) achieve a better understanding of precipitation effects on ecosystem processes and the time lags generated by vegetational constraints to climate changes.

Présentation : USDA

Page publiée le 7 décembre 2015, mise à jour le 7 novembre 2017