东北地区参考蒸散量的变化特征及其成因分析

蒸散是水分运动过程中地表热量平衡和水分平衡的组成部分,是影响气候变化的重要一项。进行蒸散量变化的研究,对了解气候变化、探讨水分循环变化规律具有十分重要的意义。论文利用东北地区124个气象站1961—2007年的日气象数据,采用Penman-Monteith方程计算了参考蒸散量,分析了参考蒸散量的变化趋势及其变化原因。结果表明,在这47 a间,东北地区年平均气温以0.38℃/(10 a)的趋势递增,但是参考蒸散量总体上却以4.4 mm/(10 a)的速度递减。在地区分布上,三分之二的地区参考蒸散量呈下降趋势,显著下降的地区集中在辽宁朝阳地区,三分之一的地区参考蒸散量呈上升趋势,主要集中在辽宁南部和吉林东部地区。对有关各气象因子分析表明,影响参考蒸散量的主要因子为日照时数和风速。

Changes in Reference Evapotranspiration and Its Causes in Northeast China

Reference evapotranspiration is an important component of the thermal balance and water budget during the water cycle of the earth surface; it is subjected to climate change directly. The research on reference evapotranspiration changes could help us understanding the characteristics of climate change and regional water cycle. Based on the observation data of temperature, wind, vapor pressure and sunshine hours collected from 124 weather stations from 1961 to 2007, the reference evapotranspiration in Northeast China was calculated by using Penman-Montieth model. Spatial-temporal characteristics of reference evapotranspiration and its causes in Northeast China were evaluated by space and time series analysis method. The results showed the reference evapotranspiration has continuously decreased at a rate of 4.4 mm/decade in Northeast China, but the annual mean temperature has increased at a rate of 0.38℃/decade. In the 1960s to the 1990s, the trend of reference evapotranspiration declined, and the trend of rising was significant in the 21st century. The average of spring and summer reference evapotranspiration in Northeast China decreased at a rate of -4.2 mm/10 a and-2.2 mm/10 a. There was a slight increase in reference evapotranspiration in autumn and winter at the rate of 0.3 mm/10 a and 1.6 mm/10 a in the recent 47 years. For spatial distributing characteristics of the average annual reference evapotranspiration, two-thirds of the region show decreasing trend especially in Chaoyang region of Liaoning Province, and one-third of the region show increasing trend especially in the south of Liaoning and the east of Jilin. The reference evapotranspiration was increased suddenly in spring from 1969, in summer from 1963, in autumn from 1963 and in winter from 1990. The correlation analysis of meteorological factors indicated that the most important factors which could influencing the reference evapotranspiration were sunshine duration and wind speed. Besides the meteorological factors influencing reference evapotranspiration, great concern has been given to the geographical location, land use, vegetation coverage and human activity.