1960—2014年松花江流域降雨侵蚀力时空变化研究

Spatial and Temporal Variation Characteristics of Rainfall Erosivity in the Songhua River Basin from 1960 to 2014

基于松花江流域及其邻近61个气象站1960—2014年逐日降雨数据,采用Mann-Kendall非参数趋势检验、小波周期分析和地统计插值方法,分析流域内不同地形区和子流域年降雨侵蚀力时空分异特征及其影响因素。结果表明:1)松花江流域多年平均降雨侵蚀力为1 717.6MJ·mm·hm^(-2)·h^(-1)·a^(-1),呈波动变化趋势,存在以15.2 a为主周期和4.7 a为小周期的周期性变化特征,且在1982和1998年发生显著突变;2)松花江流域降雨侵蚀力空间分布特征与降雨量分布特征基本一致,自东南向西北递减,与东南季风的影响区域相吻合;流域年降雨侵蚀力变化趋势呈现明显的区域分异,在流域西北地区年降雨侵蚀力呈增加趋势,而在中部平原区的东北部和西南部呈现下降趋势;3)年降雨侵蚀力随地形的变化表现为东部丘陵山地区>中部平原区>西部山地区。在东部丘陵山地区年降雨侵蚀力与经度、纬度显著相关(P<0.01),而在中部平原区和西部山地区降雨侵蚀力与海拔、经度和纬度关系不甚明显;4)流域内各子流域年降雨侵蚀力存在明显分异,年降雨侵蚀力在各子流域的变化趋势表现为从第二松花江流域到流域中游再到嫩江流域呈依次降低趋势,其分布特征与降雨量的分布一致,各子流域年降雨侵蚀力均呈不显著的降低趋势。

Soil erosion is one of the most serious global ecological environmental issues and rainfall erosivity is an important parameter influencing soil loss. This paper analyzed spatial and temporal variation characteristics of rainfall erosivity in different morphologic regions and sub- river basins within the Songhua River Basin from 1960 to 2014 based on Mann- Kendall,Wavelet Analysis and Arc GIS interpolation method. The results showed that the average rainfall erosivity in the Songhua River Basin was 1 717.6 MJ·mm·hm^（-2）·h^（-1）·a^（-1）and the trend of change was not significant whereas significant abrupt changes showed in 1982 and 1998.The main period was 15.2 a while the minor period was 4.7 a. The spatial variation of rainfall erosivity was generally consistent with the spatial variation of precipitation. Rainfall erosivity decreased from southeast to northwest, which was consistent with the influenced region of the southeast monsoon. The trend of rainfall erosivity varied in different sub- regions in the Songhua River Basin. Rainfall erosivity showed increasing trend in northwestern part of the basin and a deceasing trend in north eastern and south western part of the central plains region.There was a strong correlation between the rainfall erosivity and precipitation, which sequenced as eastern mountainous hilly region, central plains region and western mountain areas. In eastern mountainous hilly region, the rainfall erosivity significantly correlated with latitude and longitude, whereas in central plains region and western mountain areas there were no significant correlations between the rainfall erosivity and latitude, longitude as well as altitude. Rainfall erosivity varied in different sub-river basins within the Songhua River Basin.The rainfall erosivity decreased from the second Songhua River Basin, the midstream area of the Songhua River to the Nenjiang River Basin, which was consistent with the distribution of precipitation. In all sub- river basins within the Songhua River Basin, the rainfall erosivity showed a non-significant downward trend during the past 55 years.