AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING-TIANJIN-HEBEI REGION UNDER CLIMATE CHANGE

于占江周伟灿张晓

Nanjing University of Information Science and TechnologyShijiazhuang Meteorological BureauCollege of Resources and Environment, Shijiazhuang University

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), wind 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_wand R_ndecreased significantly, whereas T_min, T_maxand P_wvincreased considerably.（2） In the BTH region, ET₀ also exhibited a significant decreasing trend, and the sensitivity of ET₀ to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET₀ was most sensitive to P_wvin the fall and winter and R_nin the spring and summer. On the annual scale,ET₀ was most sensitive to P_wv, followed by R_n, V_w, T_maxand T_min. In addition, the sensitivity coefficient of ET₀ with respect to P_wvhad 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.

基金资助：

National Natural Science Foundation of China（41475054）；