Evaluation of Landsat-Based METRIC Modeling to Provide High-Spatial Resolution Evapotranspiration Estimates for Amazonian Forests
1
Geospatial Sciences Center of Excellence, South Dakota State University, Brookings, SD 57007, USA
2
Biosystems and Agricultural Engineering Department, Oklahoma State University, Stillwater, OK 74078, USA
3
South Dakota Water Resources Institute, South Dakota State University, Brookings, SD 57007, USA
4
Campus Floresta, Universidade Federal do Acre, Rio Branco de69920-900, Brazil
*
Author to whom correspondence should be addressed.
Academic Editors: Gabriel Senay and Prasad S. Thenkabail
Remote Sens. 2017, 9(1), 46; https://doi.org/10.3390/rs9010046
Received: 4 October 2016 / Revised: 24 December 2016 / Accepted: 28 December 2016 / Published: 6 January 2017
While forest evapotranspiration (ET) dynamics in the Amazon have been studied both as point estimates using flux towers, as well as spatially coarse surfaces using satellite data, higher resolution (e.g., 30 m resolution) ET estimates are necessary to address finer spatial variability associated with forest biophysical characteristics and their changes by natural and human impacts. The objective of this study is to evaluate the potential of the Landsat-based METRIC (Mapping Evapotranspiration at high Resolution with Internalized Calibration) model to estimate high-resolution (30 m) forest ET by comparing to flux tower ET (FT ET) data collected over seasonally dry tropical forests in Rondônia, the southwestern region of the Amazon. Analyses were conducted at daily, monthly and seasonal scales for the dry seasons (June–September for Rondônia) of 2000–2002. Overall daily ET comparison between FT ET and METRIC ET across the study site showed r2 = 0.67 with RMSE = 0.81 mm. For seasonal ET comparison, METRIC-derived ET estimates showed an agreement with FT ET measurements during the dry season of r2 >0.70 and %MAE <15%. We also discuss some challenges and potential applications of METRIC for Amazonian forests.
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Keywords:
evapotranspiration; METRIC; Landsat; rainforests; Amazon
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MDPI and ACS Style
Numata, I.; Khand, K.; Kjaersgaard, J.; Cochrane, M.A.; Silva, S.S. Evaluation of Landsat-Based METRIC Modeling to Provide High-Spatial Resolution Evapotranspiration Estimates for Amazonian Forests. Remote Sens. 2017, 9, 46.
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