关键词: 气候变化, Penman-Monteith模型, 参考作物蒸散量, 海河流域

Abstract:

Based on the daily data of 159 meteorological stations over the Haihe River basin during 1961-2014, the potential evapotranspiration (ET0) was calculated by Penman-Monteith equation to analyze the sensitivity coefficients of ET0 to meteorological elements including maximum temperature, minimum temperature, relative humidity, average wind speed and sunshine duration. Additionally, the dominant factors influencing ET0 change were discussed combined with the multi-year relative variations of meteorological elements. The results show that annual mean ET0 over the Haihe River basin reduced significantly with the rate of 22.7 mm·(10 a)-1 from 1961 to 2014, and the mutation occurred in 1979. From the spatial distribution, ET0 reduced significantly in the most of the basin, except for the northwestern part. The sensitive coefficients of ET0 to meteorological elements were almost positive, except for relative humidity. Considering the sensitive coefficients of ET0 to meteorological elements and the multi-year relative variations of each element, the relative humidity and the maximum, minimum temperature were the factors causing the increase of ET0, the average wind speed and sunshine duration were the factors causing the decrease of ET0. The sensitive coefficients of ET0 to average wind speed and sunshine duration were not the highest, but the average wind speed and sunshine duration decreased significantly and their relative variations were larger, so they contributed great to ET0 and became the dominant factors of ET0 change. To summarize, ET0 decreased significantly due to the decreasing of average wind speed and sunshine duration over the Haihe River basin.

Key words: climate change, Penman-Monteith, potential evapotranspiration, Haihe River basin