Comparison of Leaf Area Index, Surface Temperature, and Actual Evapotranspiration Estimated Using the METRIC Model and In Situ Measurements

• Main Authors: Arturo Reyes-González, Jeppe Kjaersgaard, Todd Trooien, David G. Reta-Sánchez, Juan I. Sánchez-Duarte, Pablo Preciado-Rangel, Manuel Fortis-Hernández
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Sensors
• Subjects: remote sensing; METRIC model; leaf area index; surface temperature; actual evapotranspiration; corn field
• Online Access: https://www.mdpi.com/1424-8220/19/8/1857

The verification of remotely sensed estimates of surface variables is essential for any remote sensing study. The objective of this study was to compare leaf area index (LAI), surface temperature (Ts), and actual evapotranspiration (ETa), estimated using the remote sensing-based METRIC model and in situ measurements collected at the satellite overpass time. The study was carried out at a commercial corn field in eastern South Dakota. Six clear-sky images from Landsat 7 and Landsat 8 (Path 29, Row 29) were processed and used for the assessment. LAI and Ts were measured in situ, and ETa was estimated using an atmometer and independent crop coefficients. The results revealed good agreement between the variables measured in situ and estimated by the METRIC model. LAI showed r² = 0.76, and RMSE = 0.59 m² m^−2, the Ts comparison had an agreement of r² = 0.87 and RMSE 1.24 °C, and ETa presented r² = 0.89 and RMSE = 0.71 mm day^−1.