哀牢山山区降水时空分布的影响因素及插值方法比较

为了研究哀牢山山区降水的影响主要因素并探索适于山区降水的空间插值方法,本文利用研究区内30个地面测站10年(2005~2014)的降雨实测数据,根据降雨的时间分布特征,将研究时段划分为年季、干季和湿季,并对影响降水的因素进行空间自相关分析,确定并组合得到影响降水的主要因子,使用留一法交叉检验插值精度,通过分析验证,寻求最优的降雨插值方法。研究结果表明,1)影响降水的主要因子为高程、纬度、坡度、坡向和主风向效应指数(PWEI);2)影响年季降水变化的主要因子为高程、纬度、坡度和坡向;影响湿季降水的主要因子为高程、纬度、坡度和PWEI;影响干季降水的主要因子为高程、坡度、纬度和坡向;3)插值过程中结合环境特征引入影响降水的因子,很大程度上提高了插值结果的精确性。由此可见,降雨插值精度不仅和插值方法本身的结构有关,更重要的是在降水特征的基础上合理筛选及引入主要环境影响因子。

A Study on Factors of Space-time Distributions of Precipitation in Ailao Mountain Area and Comparison of Interpolation Methods

In order to study the main factors influencing the precipitation of the Ailao Mountain area, and to explore the best way for spatial interpolation,rainfall data of 30 weather stations in the study area from 2005 to 2014 were analyzed. According to the characteristics of rainfall, study period was divided into "year" "dry season" and "wet season".Spatial autocorrelation of the influencing factors of precipitation was analyzed. Selection and combination of major correlation factors were conducted and Leave-One-Out method was used to check the interpolation accuracy. Furthermore, the optimal rainfall interpolation method was conducted by comparative analysis and verification. Results show that 1) the main factors affecting the mountainous area precipitation include latitude, elevation, gradient, slope direction and PWEI(prevailing wind-direction effect index); 2) the main factors affecting the annual and seasonal precipitation include latitude, elevation, gradient and slope direction; the main factors affecting the wet season precipitation are latitude, altitude, slope and PWEI; the main factors affecting the dry season precipitation are latitude, elevation, gradient and slope direction; and 3) by introducing as much as possible of environmental factors influencing precipitation, operation and analysis could largely improve the accuracy of the interpolation results. Thus it can be seen that rainfall interpolation accuracy is related to not only the structure of the interpolation method itself, but above all, reasonable selection and introduction of the main environmental impact factors based on the characteristics of precipitation.