Remote Sensing of Evapotranspiration for Global Drought Monitoring

ESSIC/CISESS scientists Li Fang, Jifu Yin, Mitchell Schull, and Jicheng Liu collaborated on a chapter in Global Drought and Flood: Observation, Modeling, and Prediction titled “Remote Sensing of Evapotranspiration for Global Drought Monitoring”.


Evapotranspiration (ET) is one of the main components of the water cycle. The latent heat from evapotranspiration is also one of the most important components of the energy cycle because it is the largest energy source for the atmosphere and thus is significant for weather and climate formation. Local scale evapotranspiration is mostly observed with ground instruments such as a lysimeter, Bowen ratio, or eddy covariance tower while regional scale evapotranspiration is estimated from surface water balance or atmospheric water balance. In recent decades, scientists have developed remote sensing approaches to retrieve regional or global scale evapotranspiration, particularly to monitor droughts.


In this chapter, the researchers briefly review evapotranspiration remote sensing studies, starting with a historical sketch before introducing the Geostationary Operational Environmental Satellites’ (GOES) ET and Drought (GET-D) product system that is operational at the National Environmental Satellite, Data, and Information Service (NESDIS). The GET-D system implements the Atmosphere–Land Exchange Inversion (ALEXI) model for estimating regional daily ET from observations of the NESDIS Geostationary Operational Environmental Satellites. The Evaporative Stress Index (ESI) based on ALEXI ET is used for monitoring drought currently for North America. An approach to merging the ESI data into microwave soil moisture observations and land-surface model soil-moisture simulations for a blended drought index is presented. The feasibility of using the ALEXI ET estimates from global satellite observations for drought monitoring is discussed.


Fang is an Assistant Research Scientist at ESSIC/CISESS and a research associate with the National Environmental Satellite, Data, and Information Service Center for Satellite Applications and Research, National Oceanic and Atmospheric Administration, College Park, MD. Her current research area is the extraction of land-surface parameters (temperature, emissivity and surface radiation) from multi-source remote sensing (active/passive, multi-angle, and multi-channel) in support of drought monitoring. 


In addition to his work at ESSIC, Yin is responsible for product development and analysis at NOAA/NESIS/STAR. His research interests include data assimilation, drought monitoring, microwave satellite soil moisture retrievals and land surface model.


To access the article, click here: “Remote Sensing of Evapotranspiration for Global Drought Monitoring”.