云南省大气中水资源分布特征初探

Distribution Characteristics of Yunnan Province Atmospheric Water Resource

利用1961—2004年云南124个气象站逐月降水(P)和气温(t)观测资料,依据高桥浩一郎的陆面实际蒸散发经验公式(以下简称高桥公式),计算了云南地面蒸发(E)和可利用降水(P-E)等与水资源有关的主要物理量,从大气可提供的水资源部分,分析了云南水资源各分量的时空演变特征及其显著周期,并对云南水资源进行了初步的区划。结果表明:云南大气中水资源各分量区域分布差异显著,南多北少,南部梯度大,北部梯度小;云南水资源各分量P,E及P-E季节变化明显,夏季各量最大,多年平均分别为548 mm,236 mm,313 mm,各占全年的55%,45%及67%,冬季各量最小,所占全年的比例也最小,分别为5%,7%,2%;云南P,E及P-E存在明显的月际、年际及年代际变化特征,各分量最大值出现在7月,最小值出现在1月或12月,通过功率谱周期分析发现,年降水量和可利用降水量存在显著的2.6年周期,年蒸发量存在显著的2.9年周期;云南省初步可划分为水资源丰富区、缺少区及一般区3个区,它们的区域平均P-E,E及P都存在明显差异。

Using the monthly precipitation and temperature of Yunnan 124 stations from 1961 to 2004, the water resource components, such as the evaporation（E） and utilizable rainfall（P - E）, are calculated by means of Takahashi＇s evaporation equation. The temporal and spatial features of water resource components and their periods are also analyzed. Results indicate that components （ P, E, P - E） of water resource in southern area are higher than that of northern area. The grads in southern area are big and that in northern area are small. 44-year average P - E and have very similar spatial and temporal distribution. The biggest and smallest center of P - E are unanimously corresponding with P, but the value of P - E is smaller than P. The components （P, E, P - E）of water resource in Yunnan have obvious seasonal changes. The biggest value of the components （P, E, P - E） appears in summer. Their annual average values are 548 mm, 236 mm, 313 mm respectively and their ratios to the whole year are respectively 55 %, 45 % and 67 %. The smallest value of the components （P, E, P - E） appears in winter and their ratios to the whole year are respectively 5 %, 7 % and 2 %. The components （P, E, P - E） of water resource in Yunnan also have obvious inter-monthly, interannual and interdecadal changes. The biggest value appears in July and the smallest appears in January or December. The difference between the maximum and the minimum of components （P, E, P - E） of water resource is very large. At the same time, the interdecadal difference of components （ P, E, P - E） of water resource is also very obvious. P and P - E are relatively abundant from 1960s to the middle of 1970s, they are less from mid 1970s to mid 1990s and more after mid 1990s. By the power spectrum period analysis method, it is revealed that there is a significant period of 2.6 years in total annual rainfall and total annual utilizable rainfall and there is a significant period of 2.9 years in total annual evaporation. The water resource of Yunnan Province is divided into three regions： abundant region, poor region and general region. There are very obvious differences among regional and annual mean utilizable rainfall, evaporation and rainfall of the three regions.