| 英文摘要: | Based on the measurements obtained at 64 national meteorological stations in the Beijing-Tianjin-Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman-Monteith equation and its sensitivity to maximum temperature (T-max), minimum temperature (T-min), xvind speed (V-w), net radiation (R-n) and water vapor pressure (P-wv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. V-w and R-n decreased significantly, whereas T-min, T-max and P-wv, increased considerably. (2) In the BTH region, ET0, also exhibited a significant decreasing trend, and the sensitivity of ET, to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to P-wv in the fall and winter and R-n in the spring and summer. On the annual scale, ET0, was most sensitive to P-wv, followed by R-n, V-w, and T-max and T-min. In addition, the sensitivity coefficient of ET0, with respect to P-wv had a negative value for all the areas, indicating that increases in P-wv can prevent ET0 from increasing. (3) The sensitivity of ET0 to T-min and T-max; was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in P-wv and R-n. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.
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