近40年丹江口库区潜在蒸散量变化特征及影响因素

全球气候变化背景下,丹江口库区潜在蒸散量变化特征对于南水北调中线水源区水循环研究及水资源评估具有重要意义。应用Penman-Monteith蒸散模型估算潜在蒸散量,分析近40年丹江口库区潜在蒸散量和干燥度指数时间变化规律,研究结果表明:(1)丹江口库区年降水量呈波动减少趋势,年均值839.9mm,其中年降水量、雨季和旱季降水量分别以14.3mm/(10a)、4.5mm/(10a)和9.0mm/(10a)的速率减少;(2)丹江口库区年蒸散量呈波动增加趋势,年均值860.0 mm,其中年蒸散量、雨季和旱季蒸散量分别以12.2 mm/(10a)、10.2 mm/(10a)和2.9mm/(10a)的速率增加;(3)丹江口库区干燥度指数呈波动增加趋势,年均值1.07,其中年干燥度指数、雨季和旱季干燥度指数分别以0.02/(10a)、0.07/(10a)和0.31/(10a)的速率增加;(4)潜在蒸散量与干燥度指数和相对湿度呈显著负相关性,与平均风速和日照时数呈显著正相关性,与温度相关性不显著。近40年来,由于降水量减少和蒸散量增加,丹江口库区气候有向干旱化演变的趋势。

Variation characteristics and influencing factors of potential evapotranspiration in Danjiangkou reservoir area

Variation characteristics of potential evapotranspiration (ET0) has important significance in water cycle research and water resource assessment in the background of global climate change in Danjiangkou reservoir area. ET0 and dry index (DI) measured by Penman-Monteith model were analyzed based on the measured meteorological data during 1970-2009, which came from the National Meteorological Center public network. The results showed that: 1) Annual precipitation with a mean value of 839.9 mm decreased with the increment of annual series, and the annual, rainy season and dry season precipitation decreased by 14.3, 4.5 and 9.0 mm/10a respectively. 2) Annual ET0 with a mean value of 860.0 mm increased with the increment of annual series, and the annual, rainy season and dry season ET0 increased by 12.2, 10.2 and 2.9 mm/10a respectively. 3) Annual DI with a mean value of 1.07 increased with the increment of annual series, and the annual, rainy season and dry season DI increased by 0.02, 0.17 and 0.31 mm/10a respectively. 4) ET0 and DI had significant negative correlation with relative humid, and significant positive correlation with mean wind speed and sunshine hours. The climate in Danjiangkou reservoir area had a drought trend stem from the decrease of precipitation and increase of ET0 in the recent 40 years.