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| DOI：10.13522/j.cnki.ggps.2017.0439 |
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| Evapotranspiration and the Factors Affecting It in Chakou Basin Studied with the SEBS Model |
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WEN Yuanyuan, GUO Qingxia, WANG Yanqiang
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Shanxi Agricultural University, Taigu 030801, China； Northwest Normal University, Lanzhou 730070, China
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| Abstract: |
| 【Objective】 This paper presents a case study in the Chakou catchment to determine the evapotranspiration and the factors impacting it in the Loess Plateau, aimed to provide data for diagnosing drought and improving water management. 【Method】 We calculated daily evapotranspiration and its spatial distribution of five crop growth seasons from April to October using the SEBS model, remote sensing and meteorological data measured in the catchment. We also analyzed the dependence of the evapotranspiration on climate, temperature, NDVI, as well as terrain parameters. 【Result】 The average daily evapotranspiration in the basin was 3.34, 5.22, 5.49, 4.22 and 3.76 mm on April 21, June 8, July 26, August 27 and September 12, respectively. Compared with the reference crop evapotranspiration calculated from the Penman-Monteith formula, the model had an average relative error of 5.57%. The impact of land usage on evapotranspiration was ranked in the order of forest land > grassland > arable land > garden plot > water area > residential area. The evapotranspiration peaked in July and had a positive correlation with air temperature and surface temperature. The impact of NDVI on evapotranspiration was negligible. Spatially, the magnitude of the evapotranspiration varied in the order of northwest > southeast > center. It was also found that the evapotranspiration was negatively correlated to the temperature on soil surface and positively related to NDVI, and had no noticeable correlation to the terrain parameters. 【Conclusion】 The daily evapotranspiration calculated from the SEBS model was consistent with measurements, affected mainly by air temperature and land-surface temperature. The surface temperature and NDVI impacted the spatial distribution of the evapotranspiration across the catchment. |
| Key words: evapotranspiration; SEBS model; Chakou Basin; influencing factor |
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