汉江流域参照蒸散发和实际蒸散发计算及影响因素分析

The calculation of reference evapotranspiration and actual evapotranspiration and the analysis of climatic factors on them in Hanjiang basin

根据汉江流域1961年-2012年间的逐日气象资料,分别采用Penman-Monteith模型和GG模型计算参照蒸散发和实际蒸散发,分析了其时空变化趋势,并结合主要气候因子的变化趋势讨论了蒸散发变化的影响因素。结果表明:汉江流域参照蒸散发和实际蒸散发在过去的52年内均呈下降趋势,空间上呈东南向西北减少的分布;采用Mann-Kendall检验法发现在显著性水平0.05上,上游的参照蒸散发和中下游的实际蒸散发下降趋势显著;太阳辐射的减少是引起汉江流域参照蒸散发和实际蒸散发下降的最主要原因。

In this paper,the Penman-Monteith method and GG model were used to calculate the reference evapotranspiration and actual evapotranspiration based on the daily meteorological data in Hanjiang basin from 1961 to 2012.An analysis of the spatial distribution and temporal trend of those two evapotranspiration was carried out,and the impact of the climatic factors were also discussed combined with their changing trends.The result indicated that there was a downward trend in both reference evapotranspiration and actual evapotranspiration during the past 52 years,and the spatial distribution of those two kinds of evapotranspiration presented a decreasing trend from southeast to northwest.As for reference evapotranspiration,the decreasing trend was significant in the upper regions,while actual evapotranspiration decreased significantly in the middle and lower regions at the 0.05 significance level.And according to the analysis,it was found that the decrease of net radiation was the main cause of the decrease of the reference evapotranspiration and actual evapotranspiration in Hanjiang basin.