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International Journal of Agronomy
Volume 2017, Article ID 3632501, 16 pages
Research Article

Comparative Analysis of METRIC Model and Atmometer Methods for Estimating Actual Evapotranspiration

1Department of Agricultural and Biosystems Engineering, South Dakota State University, Brookings, SD 57007, USA
2Minnesota Department of Agriculture, Saint Paul, MN, USA
3Iowa Soybean Association, Ankeny, IA, USA

Correspondence should be addressed to Arturo Reyes-González; xm.bog.pafini@orutra.seyer

Received 28 April 2017; Revised 23 September 2017; Accepted 9 October 2017; Published 3 December 2017

Academic Editor: Othmane Merah

Copyright © 2017 Arturo Reyes-González et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Accurate estimation of crop evapotranspiration (ET) is a key factor in agricultural water management including irrigated agriculture. The objective of this study was to compare ET estimated from the satellite-based remote sensing METRIC model to in situ atmometer readings. Atmometer readings were recorded from three sites in eastern South Dakota every morning between 8:15 and 8:30 AM for the duration of the 2016 growing season. Seven corresponding clear sky images from Landsat 7 and Landsat 8 (Path 29, Row 29) were processed and used for comparison. Three corn fields in three sites were used to compare actual evapotranspiration (). The results showed a good relationship between estimated by the METRIC model (-METRIC) and estimated with atmometer (-atm) ( = 0.87, index of agreement of 0.84, and RMSE = 0.65 mm day−1). However, -atm values were consistently lower than -METRIC values. The differences in daily between the two methods increase with high wind speed values (>4 m s−1). Results from this study are useful for improving irrigation water management at local and field scales.