华南湿热山地小流域径流对气候变化和人类活动的响应——以宁江为例

基于1953—2013年宁江流域5个气象站日气温、降水量及控制站河口水文站月径流量数据与1986年、1995年、2005年、2013年宁江流域土地覆被分类数据,运用Mann-Kendall趋势分析、小波分析及累计量斜率变化比较法探讨了1953—2013年宁江流域气候变化与人类活动对径流变化影响。结果表明:(1)1953—2013年宁江流域温度发生显著上升,变化率为0.139℃/10a,降水变化波动较小,而径流量出现显著下降。(2)1990年前流域内径流量与气温、降水存在较为明显的27a周期规律,1990年以来受人类活动影响加大,径流量变化周期受到破坏,未能体现全域性;但在小尺度周期11a上仍与降水量保持同步,表明宁江流域径流量主要受降水影响。(3)随着经济发展以及水土保持工作的进行,到2013年林地面积占整个流域的73.8%,草地面积下降41.6%,耕地面积减少61.2%,土地利用变化较大区域发生在兴宁市北部。(4)与1953—1958年比,1959—2008年宁江流域径流量增加气候变化和人类活动贡献率分别为62.2%和37.8%,2009—2013年降水和人类活动对径流减少贡献率为45.8%和54.2%。

Response of Runoff to Climate Change and Human Activities in the River Basin of Southern Humid Area——A Case Study Of Ning Jiang

Based on the data of daily temperature and precipitation of six meteorological stations in Ningjiang River Basin and hydrological data gathered from Hekou station from 1953 to 2013,landscape pattern metrics with land use and land cover date derived from the Landsat TM imagery acquired in 1986,1995,2005 and 2013,we used the methods of Mann-Kendall trend analysis,Wavelet analysis and SCRAQ method aiming to analyze the contribution ratio of precipitation and human activities to the runoff in the Ningjiang River Basin.The results showed that:(1) the temperature presented significantly increasing trend and runoff demonstrated the decreasing trend,the precipitation appeared weakly increasing trend;(2) there was obvious correlation coefficients among temperature,precipitation and runoff at the scale of 27-year before 1990,while the scale was destroyed by human activities after 1990,it was still synchronization in scale of 11-year between runoff and precipitation,indicating that runoff changes were mainly affected by the precipitation;(3) with the development of economy and soil and water conservation from 1980s,woodland area increased by 26.2 ％,grassland area land reduced by 41.6％ and cultivated area reduced by 61.2％.The large area of land use change occurred in the northern Xingning;(4) the period from 1953 to 1958 was taken as the base period,the contribution rates of the precipitation and human activities to the increased runoff were 62.2％ and 37.8％ in the period from 1959 to 2008,the rates to the decreased runoff were 45.8％ and 54.2％,respectively,in the period from 2009 to 2013.