Long-term spatial distributions and trends of the latent heat fluxes over the global cropland ecosystem using multiple satellite-based models

PLoS One. 2017 Aug 24;12(8):e0183771. doi: 10.1371/journal.pone.0183771. eCollection 2017.

Abstract

Estimating cropland latent heat flux (LE) from continental to global scales is vital to modeling crop production and managing water resources. Over the past several decades, numerous LE models were developed, such as the moderate resolution imaging spectroradiometer LE (MOD16) algorithm, revised remote sensing-based Penman-Monteith LE algorithm (RRS), the Priestley-Taylor LE algorithm of the Jet Propulsion Laboratory (PT-JPL) and the modified satellite-based Priestley-Taylor LE algorithm (MS-PT). However, these LE models have not been directly compared over the global cropland ecosystem using various algorithms. In this study, we evaluated the performances of these four LE models using 34 eddy covariance (EC) sites. The results showed that mean annual LE for cropland varied from 33.49 to 58.97 W/m2 among the four models. The interannual LE slightly increased during 1982-2009 across the global cropland ecosystem. All models had acceptable performances with the coefficient of determination (R2) ranging from 0.4 to 0.7 and a root mean squared error (RMSE) of approximately 35 W/m2. MS-PT had good overall performance across the cropland ecosystem with the highest R2, lowest RMSE and a relatively low bias. The reduced performances of MOD16 and RRS, with R2 ranging from 0.4 to 0.6 and RMSEs from 30 to 39 W/m2, might be attributed to empirical parameters in the structure algorithms and calibrated coefficients.

MeSH terms

  • Algorithms
  • Crops, Agricultural*
  • Ecosystem*
  • Hot Temperature*
  • Models, Theoretical*
  • Remote Sensing Technology*

Grants and funding

This work was partially supported by the High-Tech Research and Development Program of China (Grant 2013AA122801), the Natural Science Fund of China (Grants 41205104 and, 41201331), the National Basic Research Program of China (Grant 2012CB955302), the Fundamental Research Funds for the Central Universities (Grant 2012LYB38), the youth talent support program of College of Global Change and Earth System Science (312231103) and the High Resolution Earth Observation Systems of National Science and Technology Major Projects (Grant 05-Y30B02-9001-13/15-9). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.