摘要
土壤湿度是陆面与大气能量和物质交换的关键物理量,除地面观测外,卫星遥感也是获取土壤湿度的重要手段。本文针对欧洲卫星气象中心(EUMETSAT)基于卫星遥感而研发的面向水文气象卫星应用产品(H-SAF)中的土壤水分指数(SM-DAS-2)产品,分析产品在淮河流域土壤水分监测中的适用性,为在淮河流域利用该产品开展农田生态监测奠定基础。首先,分析了该产品监测得到的中国土壤表层水分空间分布特征,在此基础上,总结淮河流域表层土壤湿度的时空分布特征;并结合中国气象局发布的中国逐日降水量格点化产品,分析表层土壤湿度与降水量之间的相关关系,最后通过分析淮河流域土壤湿度与地面降水之间的对应关系,探讨土壤湿度对降水的响应时间。从分析结果来看,对于全国而言,该产品能够有效地反映出土壤湿度的分布特征,并且能够刻画出较细致的空间分布规律。在淮河流域,土壤湿度产品和人工观测数值之间具有性较好的相关性(相关系数为0.51,通过置信度0.05的t检验),但SM-DAS-2产品指数偏低(SMDAS-2产品的年均值为0.6,地面观测站监测的表层土壤湿度为0.69)。表层土壤湿度总体上保持"南高北低"空间分布特征,并且空间分布存在着季节性差异。山区和河流附近区域是土壤湿度的高值中心,这一特征在夏秋两季最为显著。表层土壤湿度与降水之间存在显著的相关关系,而在山区和河流附近,两者间的相关性变差。从时间上看,夏季是淮河流域表层土壤湿度与同期降水相关性最好的季节,总体上降水发生3 d以后表层土壤湿度才会对降水的变化产生响应,土壤湿度对降水变化的响应时间最长能延长到10~15 d。
Soil moisture is a key factor for the energy and matter exchange between land surface and atmosphere. In addition to the field observation, satellite remote sensing is also an important method for the soil moisture measure. In this study, the soil moisture index in the roots region product （SM-DAS-2） which is developed by EUMETSAT Hydrology Satellite Application Facility （HSAF） is applied in Huaihe River Basin, and the applicability of this produce in soil moisture monitoring is analyzed to provide better foundation for the application of this product. In this paper, the ability of monitoring the soil moisture over China is analyzed at the first step. And then, the spatial and temporal characters of soil moisture in Huaihe River basin were studied, and its relationship with the precipitation was analyzed with daily precipitation products from China Meterological Administration （CMA）. At last, the relationship of SM-DAS-2 and precipitation is calculated to discuss the response time of soil moisture to precipitation downloaded from CMA. As the results shown, SM-DAS-2 data could embody the spatial characteristics of soil moisture distribution in China. As to Huaihe River Basin, the soil moisture indexes of SM-DAS-2 were similar to the observed data in Meteorology Observatory （correlation coefficient was 0.51, which was tested by T with confidence level of 0.05）. But soil moisture indexes of SM-DAS-2 were lower than observation data （annual data of SM-DAS-2 was 0.6, and the observation data was 0.69）.The surface soil moisture shows a “Dry North, Wet South” pattern, and it was changed with season. The wet center is located in the mountain and the river areas which are stronger in summer and autumn. The study also shows that the soil moisture was obviously increasing with the rainfall. However, the relationship was less obvious in the mountain and the river regions. In summer, this relationship is even stronger when compared with other
出处
《生态环境学报》
CSCD
北大核心
2017年第4期561-569,共9页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(41275030)
公益性行业(气象)科研专项(GYHY201306040)
安徽省自然科学基金项目(1508085MD64)
中国气象局项目(CMAGJ2015M28)
