【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(ET_0) 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_(max)and P_(wv)increased considerably.(2) In the BTH region, ET_0 also exhibited a significant decreasing trend, and the sensitivity of ET_0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET_0 was most sensitive to P_(wv)in the fall and winter and R_nin the spring and summer. On the annual scale,ET_0 was most sensitive to P_(wv), followed by R_n, V_w, T_(max)and T_(min). In addition, the sensitivity coefficient of ET_0 with respect to P_(wv)had a negative value for all the areas, indicating that increases in P_(wv) can prevent ET_0 from increasing.(3)The sensitivity of ET_0 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.