洱海弥苴河流域降雨侵蚀力特征研究

Characteristics of Rainfall Erosion Force of Miju River Basin of Erhai

收集了洱海弥苴河流域内5个雨量站1997—2006年共10年的逐日降雨量及洱源县气象站1957—2000年共44年的逐年降雨量资料,对比分析了不同降雨侵蚀力估算方法的适用性,在此基础上对1997—2006年间弥苴河流域降雨侵蚀力的年内和空间分布特征及1957—2000年间降雨侵蚀力的长期年际变化特征进行了较为详细的探讨。研究结果表明:RUSLE模型中采用的降雨侵蚀力估算方法,对采用不同降雨资料所估算的年均降雨侵蚀力结果均具有较高的精度;1997—2006年间弥苴河流域年均降雨侵蚀力R值为1 941.8 M J.mm/(hm2.h.a),并且集中分布于6—10月,其中以7—9月的集中程度最高;1997—2006年10年内流域年均降雨侵蚀力的空间分布呈现北部→西南部→中部→东南部依次降低的特点;1957—2000年间流域年均降雨侵蚀力R值为2 352.1 M J.mm/(hm2.h.a),逐年降雨侵蚀力大致呈现出10年左右的周期性变化。

It selects 10-year daily rainfall data from 1997 to 2006 of 5 rain gauge stations of Miju River basin in Erhai and 44-year yearly rainfall data from 1957 to 2000 of Eryuan County Meteorological Station,compares and analyzes the applicability of estimation method of different rainfall erosion and discusses the characteristics of spatial distribution and rainfall erosion force of the river basin within a year of 1997-2006 period and long-term variation characteristic of rainfall erosion force of 1957-2000 period based on that condition.The outcomes show that the estimation method used by RUSLE model has higher precision of annual average erosion force calculated by different rainfall data;the R value of annual average rainfall erosion force of the basin of 1997-2006 period is 1941.8 MJ·mm/(hm2·h·a) and concentrates in the period of June-October,of which, mostly concentrates in July-September period;the 10-year spatial distribution of annual average rainfall erosion force of the basin of 1997-2006 period gradually decreases from north → southwest → the middle part → southeast and;the R value of annual average rainfall erosion force of the basin of 1957-2000 period is 2 352.1 MJ·mm/(hm2·h·a),showing that the variation is in about 10-year cycle.