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Journal of Applied Remote Sensing • Open Access

Evaluation of a moderate resolution imaging spectroradiometer triangle-based algorithm for evapotranspiration estimates in subalpine regions
Author(s): Kyle R. Knipper; Alicia M. Kinoshita; Terri S. Hogue

Paper Abstract

The current study evaluates the application of a moderate resolution imaging spectroradiometer (MODIS) triangle-based method to estimate evapotranspiration (ET) in subalpine environments. Topographic corrections and improved soil moisture representation are applied to a previously developed net radiation (Rn) model and triangle algorithm to develop an 8-day average ET product based solely on satellite products. We evaluate modeled Rn and MODIS ET (MOD-ET) against ground-based values at four sites in the Sierra Nevada of northern California and also present a comparison between two monthly distributed ET datasets [operational simplified surface energy balance (SSEBop) and MODIS MOD16]. Modeled daily Rn results indicate a systematic underestimation (between −83 and −110  W/m2 bias). Consequently, Rn is bias-corrected before calculating MOD-ET. MOD-ET validation shows correlations between 0.15 and 0.45 with errors between 73 and 126  W/m2. MOD-ET and SSEBop ET report correlations of 0.36 and 0.20, respectively, on average, compared to ground-based monthly ET. MOD16 underestimates monthly totals, with bias values on the range of −14 to −144  W/m2. Semiarid conditions and scale differences between the MODIS pixel and station contribute to errors with respect to observation. Overall, MOD-ET provides reasonable ET estimates and may better capture temporal dynamics in environments undergoing chronic disturbance.

Paper Details

Date Published: 19 January 2016
PDF: 20 pages
J. Appl. Remote Sens. 10(1) 016002 doi: 10.1117/1.JRS.10.016002
Published in: Journal of Applied Remote Sensing Volume 10, Issue 1
Show Author Affiliations
Kyle R. Knipper, Colorado School of Mines (United States)
Alicia M. Kinoshita, San Diego State Univ. (United States)
Terri S. Hogue, Colorado School of Mines (United States)

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