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为解决气候变化与灌溉对区域参考作物蒸散量(ET0)的影响问题,利用Penman-Monteith公式计算都江堰灌区5个站点60年逐日蒸散量,定性定量研究气候变化与灌溉对灌区蒸散量的影响。结果表明:近60年灌区蒸散量总体呈降低趋势。各气候变量对蒸散量的敏感性由高到底依次为相对湿度、平均温度、日照时数、风速;风速、日照时数的降低是蒸散量下降的主要原因,灌区建设前后相比,遂宁站风速的下降趋势远大于全国风速的下降趋势,灌溉主要使区域风速显著下降。在春、夏、秋、冬、主要作物生长期,蒸散量变化的主控因素分别为平均温度、相对湿度、平均温度、相对湿度和相对湿度。灌区灌溉与气候变化对蒸散量影响分别为49.97%、50.03%,因此气候变化与灌溉是引起灌区蒸散量变化的重要原因。
In order to solve the impact of climate change and irrigation on regional reference crop evapotranspiration (ET0), Penman-Monteith formula was used to calculate the daily evapotranspiration of five stations in Dujiangyan Irrigation Area over the past 60 years, and qualitative and quantitative study of the impacts of climate change and irrigation on evapotranspiration was conducted. The results showed that the evapotranspiration of irrigation area in the recent 60 years showed a decreasing trend. The sensitivity of each climate variable to evapotranspiration was relative humidity, average temperature, sunshine duration and wind speed from the highest level to the lowest level. The decrease of wind speed and sunshine duration was the main reason for the decrease of evapotranspiration. Compared with before and after the construction of irrigation area, The declining trend is far greater than the national wind speed declining trend, and irrigation mainly causes the regional wind speed to drop significantly. The main controlling factors of evapotranspiration in spring, summer, autumn, winter and main crop growing period were average temperature, relative humidity, average temperature, relative humidity and relative humidity respectively. The impacts of irrigation and climate change on evapotranspiration are 49.97% and 50.03% respectively. Therefore, climate change and irrigation are the important reasons that cause the variation of evapotranspiration in irrigation area.