喻家山土壤含水率对次降雨事件的响应及影响因素

Responses of soil moisture content to rainfall events and its influencing factors at Yujia Mountain

研究武汉市喻家山试验区次降雨事件下土壤含水率的响应特征和影响因素,为后续包气带和饱水带地下水储量变化研究提供科学依据。基于野外降雨、地下水位和土壤含水率的连续监测数据,分析4个典型剖面土壤含水率的动态变化及其对6次降雨事件的响应特征;以S4剖面为例采用灰色关联度法分析影响土壤含水率响应幅度的主导因子。结果表明:相对于喻家山山体较高位置,南坡和北坡坡脚的地形高程低,地下水位埋深小,土壤颗粒细,分选好,土壤剖面的含水率平均值较大,变异系数较小;4个剖面的土壤含水率大小和初始响应时间随埋深增加并不是系统地增加,反映研究区土壤剖面非均质性较强;平均降雨强度和最大降雨强度与含水率响应幅度间的关联度最大,是控制试验区含水率响应的主导因子。位于喻家山南坡坡脚实验大楼内的2个土壤剖面受人类建筑活动、周围绿化和浇水影响较大,后期应结合长期监测资料综合分析土壤含水率的响应特征和主控因素。

The response characteristics and influencing factors of soil moisture content under individual rainfall events at the test site of Yujia Mountain in Wuhan,China,were studied to provide a scientific basis for subsequent studies on groundwater storage changes in the unsaturated and saturated zones.Based on the continuous field monitoring data of rainfall,groundwater level and soil moisture content,the dynamic changes in soil moisture content in four typical profiles and their response characteristics to six rainfall events were analysed.Taking the S4 profile as an example,the dominant factors of the response amplitude of soil moisture content were identified using the grey correlation method.Compared with the higher position of Yujia Mountain,the foot of the southern and northern slopes is lower,with a shallow water table,fine soil particles,and good sorting.As a result,the mean value of the soil moisture content was larger,and the coefficient of variation was smaller.The soil moisture content and initial response time of the four profiles did not increase systematically with increasing burial depth,reflecting the strong heterogeneity of the soil profiles in the study area.The correlation analysis between the response amplitude of soil moisture content and the four influencing factors showed that the average and maximum rainfall intensities were the dominant factors.The two soil profiles located in the experimental building at the foot of the southern slope are strongly affected by human construction activities,surrounding greening and watering.The response characteristics and main influencing factors of soil moisture content should be comprehensively analysed based on long-term monitoring data in the future.