青海黄南地区近54年蒸发量变化特征及其影响因子

Evaporation and Its Influencing Factors in Huangnan of Qinghai Province in Recent 54 Years

利用青海省黄南地区近54a(1960—2013年)蒸发量、气温、降水量、日照时数、水汽压等资料,应用地理信息系统、数理统计、线性回归和Mann-Kendall检验等方法分析了黄南地区蒸发量的空间及时间变化趋势,并对黄南地区蒸发量变化特征及其影响因子进行了诊断研究。结果表明:黄南地区年平均蒸发量呈明显的下降趋势,20世纪60—70年代为蒸发量偏多阶段,80年代及后为偏少阶段;黄南地区蒸发量最大的季节是春季和夏季,各季蒸发量均呈减少趋势;黄南地区年蒸发量在1973年发生了由多到少的突变,春、夏、秋、冬季分别发在1973、1975、1976和1974年;分析影响蒸发量的相关因子,蒸发量与日照时数呈显著的正相关关系,与水汽压和降水量呈显著的负相关关系,日照时数的减小是蒸发量减少的主要影响因子。

Based on the data of evaporation,temperature,precipitation,sunshine duration,vapor pressure from 4 meteorological stations in Huangnan of Qinghai Province in the recent 54 years,using the data from the geographic information system,by means of the methods of mathematical statistics,linear regression and Mann-Kendall test,the trends of spatial and temporal variation of evaporation in Huangnan are studied,and the characteristics of evaporation variation and the influencing factors are analyzed.The results indicated:(1)The average annual evaporation in Huangnan was 1441.5 mm from 1961 to 2013,which showed an obvious decreasing trend.In the 1960 sand 1970 s,the evaporation capacity had an increasing tendency.From the 1980 s,the evaporation capacity decreased,presenting a declining trend.(2)The evaporation was the greatest in spring and summer,accounting for over 60 percent of average annual capacity,and it was less in autumn and winter.Evaporation capacity saw a decreasing trend in all seasons,especially in spring,then in summer.(3)In 1973,Huangnan experienced a sudden change in annual evaporation from great to low,and seasonal sudden change from great to low happened in the spring of 1973,summer of 1975,autumn of 1976,and winter of 1974,respectively.(4)The analysis of the influencing factors of evaporation shows that evaporation had a significant positive correlation with sunshine and a negative correlation with vapor pressure.The reduction of sunshine duration was the main influencing factor of evaporation decrease.