Corey Walker

Date of Award


Document Type


Degree Name

Master of Science (MS)


Atmospheric and Earth Science

Committee Chair

John Mecikalski

Committee Member

Vilkalp Mishra

Committee Member

John Christy


Soil moisture--Remotes sensing, Soil moisture--Ala.bama--Measurement--Instruments


The Atmospheric Land Exchange Inverse (ALEXI) model uses Geostationary Operational Environmental Satellite (GOES) thermal bands to derive daily evapotranspiration estimates at the continental scale. These data are used to derive a weekly Evaporative Stress Index (ESI) representing standardized anomalies of the actual to potential evapotranspiration ratio (AET/PET). ESI is functionally related to the root zone soil moisture content. As the AET/PET ratio approaches unity, the greater the available water at the root zone is for agricultural fields, whereas the opposite is true during periods of drought. However, the relationship between ALEXI ESI and root zone soil moisture may not be linear or consistent across space or time. Therefore, there is a desire to better understand the relationship between ALEXI ESI and real soil moisture values, as well as an empirical knowledge of what ESI means in relation to point measurements of soil moisture on the ground. This thesis will provide such discussion on ESI and weekly-corrected, in-situ, volumetric soil moisture values from a collection of SCAN stations across Alabama. The implications of this research will lead to a better understanding of how ALEXI ESI can be used as an indicator for agriculture and flash drought in the Southeastern U.S.



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