黄土高原地区降水资源特征及其对植被分布的可能影响

THE FEATURES OF PRECIPITATION IN THE LOESS PLATEAU AND ITS POSSIBLE IMPACTS ON VEGETATION DISTRIBUTION

选取了黄土高原 4 1个站点 1 96 1年～ 1 990年的月降水资料 ,计算并分析了黄土高原地区多年平均年降水量、年内各个季节的降水分配比例、年降水变率和离差系数等分布特征 ,同时对黄土高原不同地区光热水资源的耦合特征和土壤水分在雨季恢复的程度进行了分析。结果表明 :森林地带分布在黄土高原东南部和立地条件好的山地 ;荒漠草原带分布在水热资源缺乏的西北部 ;森林草原过渡带和典型草原带分布在森林带和荒漠草原带之间 ,是黄土高原地区的主要植被地带。最后 ,给出了林草适宜分布区域及其受限区域 。

Using the monthly precipitation data from 1961 to 1990 at 41 stations in the Loess Plateau, the features of the precipitation resources including seasonal distribution of annual precipitation, the ratio of maximum and average, the ratio of maximum and minimum, the annual precipitation change rate, and the coupling combination with radiation and heat resources are analyzed. Then, the possible impacts of precipitation on vegetation distribution are discussed. The results show that the distribution of vegetation is determined by the coupling among the resources of light, heat and water. The forest is only distributed in the southeast area where are abundant in resources of heat and water; the desert grassland is located in the northwest where is short of heat and water resources. The typical grassland and the transition from forest to grassland, which are main vegetation zone in Loess Plateau, are distributed between the two zones as forest and grassland. At last, the areas which are favorable for forest and grass in the Loess Plateau are identified, which can be taken as the reference for the vegetation rehabilitation and ecological construction in this region.