渭北旱塬地区典型频率年降水量分布特征研究

Research on Distribution Characteristics of Different Frequency Annual Precipitation in Northern Weihe Loess Plateau

不同频率降水的分布特征研究对水资源的高效利用和农业布局有重要意义。利用ArcGIS软件对陕西省渭北旱塬区28个县(区)1981—2005年的日降水资料进行整理分析,构建各站的年降水序列,利用克里金插值法绘制5%、50%和95%三个典型频率年降水量等值线图,分析了各频率下年降水量空间分布的特点。结果表明:渭北旱塬地区频率为5%的丰水年年降水量分布从东北至西南逐渐增多;频率为50%的平水年年降水量分布以铜川市宜君县和宝鸡市中部为最高,并向四周逐渐减少;频率为95%的枯水年年降水量分布与平水年的趋势相似,但降水量相对较大的区域扩大;研究区东北部区域较其他地区而言丰水年降水偏少,枯水年降水偏多,总体降水量分布较为均匀,应属于不易发生旱涝灾害的区域。

The study of characteristics of different frequency annual precipitation has important significance in efficient utilization of water resources and layout of agriculture. Different frequencies of annual precipitation in northern Weihe loess plateau were researched by using daily precipitation from 1981 to 2005 in 28 counties of the studied area through Arc GIS software. p = 5%,p = 50% and p = 95% annual precipitation contour maps of northern Weihe loess plateau by using the kriging interpolation method were drew and their characteristics were analyzed. It shows that in wet years( p = 5%),annual precipitation increases gradually from northeast to southwest; in normal years( p = 50%),Yijun and the central of Baoji have the highest annual precipitation and less in the surrounding area; in dry years( p = 95%),the annual precipitation is similar to that of the normal year,but the area is expanded; the northeast of the studied area is the region that hardly occurs drought or flood.