Özet:

: Climate change refers to the statistically significant changes in the mean and dispersion values of meteorological factors. Characterizing potential evapotranspiration ( ET 0) and its climatic causes will contribute to the estimation of the atmospheric water cycle under climate change. In this study, based on daily meteorological data from 26 meteorological stations in Heilongjiang Province from 1960 to 2019, ET 0 was calculated by the Penman–Monteith formula, linear regression method and the Mann–Kendall trend test were used to reveal the seasonal and inter-annual changing trend of ET 0. The sensitivity-contribution rate method was used to clarify the climatic factors affecting ET 0. The results showed that: (1) From 1960 to 2019, the maximum temperature ( T max), minimum temperature ( T min) and average temperature ( T mean) showed an increasing trend, with climate tendency rate of 0.22 °C per decade (10a), 0.49 °C/(10a), 0.36 °C/(10a), respectively. The relative humidity ( RH), wind speed ( U) and net radiation ( Rn) showed a decreasing trend, with a climate tendency rate of −0.42%/(10a), −0.18 m/s/(10a), −0.08 MJ/m 2/(10a), respectively. (2) ET 0 showed a decreasing trend on seasonal and inter-annual scales. Inter-annually, the average climate tendency rate of ET 0 was −8.69 mm/(10a). seasonally, the lowest climate tendency rate was −6.33 mm/(10a) in spring. (3) ET 0 was negatively sensitive to T min, and RH, while positively sensitive to T max , T mean U and Rn, its sensitivity coefficient of U was the highest, which was 1.22. (4) The contribution rate of U to ET 0 was the highest on an inter-annual scale as well as in spring and autumn, which were −8.96%, −9.79% and −13.14%, respectively, and the highest contribution rate to ET 0 were Rn and T min in summer and winter, whose contribution rates were −4.37% and −11.46%, respectively. This study provides an understanding on the response of evapotranspiration to climatic change and further provides support on the optimal allocation of regional water resource and agricultural water management under climate change.

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