太行山区降水空间扩展方法与垂直地带性分析

Comparison of the Methods of Precipitation Spatial Expansion and Analysis of Vertical Zonality in the Taihang Mountains

山区降水影响机制复杂,空间变异性强,由于观测资料稀缺,降雨数据从站点到空间的扩展一直是水文学界的难点。本文基于太行山区34个国家气象站和130个雨量站的降水实测数据,评估了距离平方反比法(IDS)、改进的降水海拔关系模型(MPAR)和两种综合方法(MPAR-IDS和IDS-MPAR)应用于太行山区降雨空间扩展的效果,探讨了山区降雨空间扩展的影响机制及方法优劣性。结果表明,4种空间扩展方法中IDS-MPAR精度最高,其年降水平均相对误差(MRE)仅8.7%,比IDS方法小14.0%,MPAR-IDS的误差比IDS低10.4%,MPAR与IDS的精度接近。基于IDS-MPAR插值结果的分析表明:太行山区降水分布规律主要受地形影响,降水等值线与山体走向基本一致;在小五台山、南太行迎风坡山腰存在一个最大降水高度,在恒山、五台山则存在两个最大降水高度,分别在迎风坡山腰和山顶附近;大同盆地等几个背风坡盆地降水很少,而喇叭口形的长治盆地降水较多。

The precipitation in mountainous area is complex in pattern partly because of strong spatial variability of rainfall distribution. Due to the scarcity of observation data,the expansion of rainfall data from sites to space has been a difficult issue of hydrography community. Based on the collected precipitation data from 34 national meteorological stations and 130 rainfall stations in the Taihang Mountains,in this paper it assessed the applicability of the Inverse Distance Square method（ IDS）,the Modified Precipitation-Altitude Relationship（ MPAR） and other two approaches combined the previous two methods（ i. e.,MPAR-IDS and IDS-MPAR） to the spatial expansion of rainfall distribution in the Taihang Mountains,and then it discussed the mechanism influencing the rainfall expansion,its methodological advantages and disadvantages. Four kinds of criteria including Coefficient of Correlation（ CC）,Mean Relative Error（ MRE）,Mean Absolute Error（ MAE） and Root Mean Square Error（ RMSE） were applied to compare the accuracy of the four interpolation methods. The pattern of spatial distribution of precipitation with the highest accuracy was used to analyze the topographic effects on precipitation,especially the issue of Maximum Precipitation Height（ MPH）. Results showed that the accuracy of IDS-MPAR was the highest among the four methods,with only 8. 7% annual MRE,14. 0% smaller than IDS method,and the error of MPARIDS was 10. 4% lower than that of IDS whereas MPAR and IDS had close accuracy. Based on IDS-MPAR interpolation analysis,it found that the spatial variation of precipitation in the Taihang Mountains was mainly affected by local terrain,and the contour of precipitation was basically parallel to the mountain stretch. There existed a maximum precipitation height on the hillside of Xiaowutai Mountain as well as South Taihang Mountain.Two maximum precipitation heights in Heng Mountain and Wutai Mountain was found at windward hillside and the peak,respectively,In Datong Basin and other leeward slope basin,rainfall was very low,while the bell-shaped Changzhi basin received more precipitation.