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| DOI：10.13522/j.cnki.ggps.2019053 |
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| Change in reference crop evapotranspiration from humid climate region of sichuan province and its determinants |
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WU Jianfei, KANG Yinhong*, LIANG Youpeng
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College of Water Conservancy and Hydropower Engineering, Sichuan Agriculture University, Ya’an 625014, China
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| Abstract: |
| 【Objective】Evapotranspiration is the most important water loss from terrestrial ecosystems and understanding its spatiotemporal change is critical for improve water management. We took the humid region in Sichuan province as an example and analyzed the temporal change in reference crop evapotranspiration (ET0) as well as its determinants in the region. 【Method】 We calculated ET0 using daily meteorological data measured from 1954 to 2009 in Ya’an based on the Penman-Monteith (PM) equation first, and then analyzed the characteristics in its change as well as its determinants using the Mann-Kendall test and path analysis respectively.【Result】The annual ET0 over the 1954—2009 was 861.2 mm, but the ET0 had been in decline at 9.3 mm/10a. Although the relative humidity remained almost unhanged (z=-0.52), wind speed (z=-7.09), sunshine hours (z=-2.61) and net radiation (z=-2.64) had all been falling accompanied by an significant rise in daily mean temperature (z=2.9). Path analysis revealed that the factors that impacted ET0 more were net radiation, relative humidity, wind speed and daily average temperature. The ET0 calculated by the Pristley-Taylor method was comparable to that estimated from the PM equation.【Conclusion】The annual average ET0 in Ya’an has been declining, and the sunshine hours is the main determinant. The Pristley-Taylor method can be used to calculate ET0 for the humid areas lacking of meteorological data. |
| Key words: reference crop evapotranspiration; Mann-Kendall test; path analysis; Pristley-Taylor method |
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