Arid Zone Research ›› 2019, Vol. 36 ›› Issue (2): 395-402.doi: 10.13866/j.azr.2019.02.15

• Water and Climate • Previous Articles     Next Articles

Dry-Wet Edge Based on Land Surface Temperature and Leaf Area Index and Estimation of Regional Evapotranspiration

WANG Jun1,2,3, LI He-ping1,2,3, LU Hai-yuan1,2,3, ZHANG Rui-qiang1,2,3, CAO Xue-song1,2,3   

  1. 1. Institute of Water Resources for Pastoral Area,China Institute of Water Resources and Hydropower Research, Hohhot 010020, Inner Mongolia,China;
    2. Institute of Water Resources for Pastoral Area, Ministry of Water Resources, Hohhot 010020, Inner Mongolia,China;
    3. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, Beijing 100038,China
  • Received:2018-05-24 Revised:2018-12-18 Published:2025-10-18

Abstract: The METRIC model was chosen to reveal the spatial ambiguity issue encountered during the calculation of regional evapotranspiration (ET) by remote sensing energy balance method. The study was based on the trend graph of surface temperature (Ts) and leaf area index (LAI). The dry pixel was chosen as the bare soil area where the Ts frequency histogram accounted for the top 5% of the high-temperature region, and the LAI frequency histogram accounted for 5% of the region. The wet pixel was chosen as the wetland or farmland where the Ts frequency histogram accounted for the last 5% of the low-temperature region, and the LAI frequency histogram accounted for the top 5% of the region. After that, the measured data of the eddy covariance system were used to verify the estimation accuracy of the model. The results showed that the average estimation accuracy of evapotranspiration in the calibration period and verification period was 15%, which was relatively reasonable compared with the previous research results. The selection scheme could help the Mapping Evapotranspiration with Internalized Calibration (METRIC) model to subjectively determine the dry-wet edge. The evapotranspiration values of different land use types were calculated, and they were in an order of ETwater>ETforest>ETarable land>ETunused land>ETurban and rural industrial land ≈ ETgrassland, which could be referred in researching the precision estimation of regional remote sensing evapotranspiration.

Key words: evapotranspiration, METRIC model, dry-wet edge, surface temperature, leaf area index, Inner Mongolia