洞庭湖典型洲滩湿地水分时空变化特征及其相关性分析

Spatiotemporal variation characteristics of moisture and its correlation analysis of in a typical beach wetland of Dongting Lake

为了分析变化条件下洲滩内部土壤水分时空变化特征及不同深度土壤水分含量和湖水位的相关性,以洞庭湖典型洲滩断面为研究对象,利用原位监测装置连续2个月监测了湖水位、大气温度及土壤水分含量的动态变化过程。结果表明:洞庭湖洲滩水分场的分布在垂向上呈现明显的分层现象,同一位置的土壤水分含量的波动幅度随着深度的增加而逐渐减小,至深层处(大于50 cm)趋于稳定,同一深度的土壤水分含量的波动幅度随着与岸边距离的增加而逐渐减小。土壤水分含量与湖水位之间的相关性随着深度的增加呈先增强后减弱的趋势,浅层及深层的土壤水分含量和湖水位之间均呈无显著相关性,地表以下50~70 cm深度处土壤水分含量与湖水位相关性较高。研究结果有助于了解土壤水分在洲滩生态系统地下含水层-土壤-大气界面的相互作用机制,为洲滩水文过程及生态环境保护研究提供重要方法和理论参考。

In order to study the temporal and spatial variation characteristics of soil moisture and the correlation between soil moisture content and lake water level in the beach wetlands under changing conditions,the typical continental wetland section of Dongting Lake was taken as the research object,and the water level,atmospheric temperature,and soil moisture content were monitored by in-situ monitoring device for two months.The results indicate that the distribution of moisture field in the wetland of Dongting Lake presents an obvious stratification phenomenon in the vertical direction.The fluctuation range of soil moisture content in the same location gradually decreased with the increase of depth,and became stable in the deep(>50 cm).The fluctuation range of soil moisture content at the same depth decreased with the increase of distance from the bank.The correlation between soil moisture content and lake water level increased first and then weakened with the increase of depth.There was no significant correlation between the soil moisture content of the shallow and deep layers and the lake water level.The soil moisture content at the depth of 50~70 cm below the surface was highly correlated with the lake water level.The results reveal the interaction mechanism of soil moisture in the underground aquifer-soil-atmosphere interface of the wetland ecosystem,and provide important methods and theoretical references for the study of hydrological processes and ecological environment protection in the wetlands.