Upper Rio Grande Basin Focus Area Study

Methods

Evapotranspiration

Evapotranspiration (ET) from irrigated croplands and native vegetation (e.g. riparian ecosystems) is a significant component of the water budget in the Western U.S., and therefore, quantification of ET is essential to water availability studies and water-use assessments for both agricultural and native lands. Remote sensing can provide useful, spatially-distributed information at a Landsat (100-meter grid) scale and has important advantages over statistical interpolation between evaporative flux towers and climate stations, or estimates made from indirect proxies, like consumption of electricity by irrigation pumps.

Study Component Lead

Gabriel Senay

USGS Earth Resources Observation and Science Center

Actual evapotranspiration (ETa) will be estimated using the Simplified Surface Energy Balance (SSEBop) model, using Landsat satellite images in conjunction with field verification. This analysis will result in a spatial distribution of annual and seasonal ETa, which will be aggregated to the HUC-8 scale. The approach to complete this study component is:

Evapotranspiration Estimates
  • Produce monthly and seasonal ET grids at the Landsat scale using the Simplified Surface Energy Balance (SSEBop) ET model for the URGB for 2015.
Field Verification
  • Verify irrigated acreage and riparian habitat in select areas to improve estimates of CU for irrigation.