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Accueil du site → Doctorat → États-Unis → 1993 → A hydrologic model for studying the influence of climate change on evapotranspiration and water yield

Utah State University (1993)

A hydrologic model for studying the influence of climate change on evapotranspiration and water yield

Sikka, Alok Kumar

Titre : A hydrologic model for studying the influence of climate change on evapotranspiration and water yield

Auteur : Sikka, Alok Kumar

Université de soutenance : Utah State University

Grade : Doctor of Philosophy (PhD) 1993

Résumé
Temperature and precipitation changes have been included in current climate change-runoff modeling studies without explicitly including the effects of vegetation changes. A procedure for estimating the impact of CO$\sb2$-induced climate and vegetation changes on actual evapotranspiration (ET), soil moisture, and water yield in a semi-arid vegetated mountain watershed is proposed and evaluated in this dissertation. A distributed parameter modeling approach is used whereby a watershed is partitioned into relatively homogeneous hydrologic response units (HRUs) to provide distributed parameter capabilities. A distributed parameter ET model is developed based on a biophysical approach for simulating actual ET from natural vegetated watersheds with closed or incomplete canopy cover. The hydrologic model, called Climate Vegetation Hydrologic Model (CVHM), is developed by incorporating these modifications into an existing hydrologic model, the Precipitation Runoff Modeling System (PRMS). Leaf area index (LAI) is used in the model as a measure of vegetation structure and as a surrogate for plant size to quantify energy and mass (water) exchange. Canopy conductance (reciprocal of resistance) is another important vegetative parameter which is included to represent CO$\sb2$-induced changes in vegetation. A new procedure is presented and evaluated for partitioning a watershed into HRUs through the utilization of digital terrain data and the application of an unsupervised fuzzy pattern recognition technique to Landsat TM data, using an interactive-graphic procedure in a GIS environment. To conduct the sensitivity analyses, climate and vegetation change scenarios are proposed based on the information from the literature. The procedure developed in this research is an effective and practical integrated approach to modeling the effects of climate and vegetation changes on the hydrologic response of watersheds.

Mots clés : Applied sciences, Hydrology, GIS, Earth sciences, Civil engineering, Agricultural engineering

Accès au document : Proquest Dissertations & Theses

Page publiée le 28 février 2015, mise à jour le 31 décembre 2016