气候变化和人类活动对伊逊河流域径流变化的影响

借助Mann-Kendall趋势检验和突变检验对气象水文序列进行一致性分析,划分基准期（1961—1979年）和影响期（① 1980—1989年、② 1990—1999年、③ 2000—2016年）,利用基准期校准的可变下渗容量（VIC）模型,采用步进式方法,探究气候变化和人类活动对伊逊河流域径流变化的波动影响过程。结果表明:研究区近56年年均气温显著升高,年降水量无明显变化趋势,流域年径流量下降趋势明显,季节尺度上流域非汛期降水量增加显著。气候变化和人类活动均会对径流产生显著影响且作用机理复杂,步进式方法对影响机理的研究较传统方法更能体现其变化过程;在降水丰沛的影响 ② 期,冬季降水量增加会显著增加流域径流量,而在降水略少的影响 ① 期和 ③ 期,蒸发量增加以及土壤含水量降低使得流域径流减少;人类活动耗水在影响 ① 期和 ③ 期引起流域径流减少并且影响作用逐渐增强,影响 ② 期由于城镇化和耕地扩张使得流域产流能力增强导致径流增加。深入研究气候变化和人类活动对径流的影响机制,可为流域水资源管理和规划提供理论依据。

Impacts of climate change and human activities on runoff variations in Yixun River Basin

According to the consistency analysis of meteorological and hydrological series, one natural period (1961-1979) and three impact periods (① 1980-1989, ② 1990-1999 and ③ 2000-2016) have been divided by the Mann-Kendall's test in the Yixun River Basin. The variable infiltration capacity (VIC) model calibrated by the streamflow data in natural period and stepwise method was used to identify the fluctuant impacts of climate change and human activities on the river runoff. Results showed that the climate change in the study area at annual scale was mainly reflected in the significant increase in temperature and there was no obvious trend in precipitation, while the runoff indicated a notable descending trend. Furthermore, the significant increase of precipitation in non-flood season was found at seasonal scale. Climate change and human activities would have significant effects on runoff with the complex mechanism; stepwise method was more appropriate for analyzing the fluctuant impacts than traditional methods. In the period ② with abundant precipitation, the increase of winter rainfall would significantly increase runoff. However, in the period with less precipitation, such as periods ① and ③, the increase of evaporation and the decrease of soil water content would be two factors causing the reduction in runoff. Water consumption reduced runoff in periods ① and ③, and the impact of human activities gradually increased. In period ②, urbanization would be the major effect of the ascending on the runoff. The studies on how climate change and human activities affect the runoff could provide theoretical principal for water resources management and planning in future.