Partitioning of evapotranspiration in remote sensing-based models

Carl J. Talsma*, Stephen P. Good, Carlos Jimenez, Brecht Martens, Joshua B. Fisher, Diego G. Miralles, Matthew F. McCabe, Adam J. Purdy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

Satellite based retrievals of evapotranspiration (ET) are widely used for assessments of global and regional scale surface fluxes. However, the partitioning of the estimated ET between soil evaporation, transpiration, and canopy interception regularly shows strong divergence between models, and to date, remains largely unvalidated. To examine this problem, this paper considers three algorithms: the Penman-Monteith model from the Moderate Resolution Imaging Spectroradiometer (PM-MODIS), the Priestley-Taylor Jet Propulsion Laboratory model (PT-JPL), and the Global Land Evaporation Amsterdam Model (GLEAM). Surface flux estimates from these three models, obtained via the WACMOS-ET initiative, are compared against a comprehensive collection of field studies, spanning a wide range of climates and land cover types. Overall, we find errors between estimates of field and remote sensing-based soil evaporation (RMSD = 90–114%, r2 = 0.14–0.25, N = 35), interception (RMSD = 62–181%, r2 = 0.39–0.85, N = 13), and transpiration (RMSD = 54–114%, r2 = 0.33–0.55, N = 35) are relatively large compared to the combined estimates of total ET (RMSD = 35–49%, r2 = 0.61–0.75, N = 35). Errors in modeled ET components are compared between land cover types, field methods, and precipitation regimes. Modeled estimates of soil evaporation were found to have significant deviations from observed values across all three models, while the characterization of vegetation effects also influences errors in all three components. Improvements in these estimates, and other satellite based partitioning estimates are likely to lead to better understanding of the movement of water through the soil-plant-water continuum.

Original languageEnglish (US)
Pages (from-to)131-143
Number of pages13
JournalAgricultural and Forest Meteorology
Volume260-261
DOIs
StatePublished - Oct 15 2018

Keywords

  • Evapotranspiration
  • Modeling
  • Partitioning
  • Remote sensing
  • Soil evaporation
  • Transpiration

ASJC Scopus subject areas

  • Forestry
  • Global and Planetary Change
  • Agronomy and Crop Science
  • Atmospheric Science

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