基于ENVISAT ASAR的长江口南汇潮滩土壤湿度定量研究

Soil moisture quantitative study for the Nanhui Tidal Flat in the Yangtze River estuary by using ENVISAT ASAR data

土壤湿度是潮滩湿地生态环境的重要参数之一。以长江口南汇潮滩为研究区,利用2005年5月2日和3日2景时序相近、低入射角HH极化的ENVISAT ASAR数据,在数据预处理的基础上,进行了入射角归一化处理,然后采用Zribi-Dechambre模型计算了南汇潮滩土壤粗糙度和土壤湿度。其土壤粗糙度分布范同为0.05～0.8 cm,土壤湿度分布范围为1%～3.8%。最后,采用上海地质调查研究院土壤湿度实测数据进行了验证,其均方根误差为3.62%,表明该方法对合成孔径雷达影像进行土壤湿度信息的提取有较好的适用性。

Soil moisture is one of the important ecology parameters of the tidal flat. In this paper, the Nanhui tidal flat in the Yangtze River estuary was taken as study area, and two close time and HH polarized ENVISAT-ASAR images with different small incidence angles for inversion were received on May 2 and 3, 2005. Then the images based on data pretreatment were normalized for angles, and inversed bare surface roughness and moisture of the Nanhui tidal flat by using Zribi-Dechambre model. The results showed that soil roughness mostly ranged from 0.05cm to 0.Scm and soil moisture mainly distributed in the range of 1%-3.8%. At last, the inversed results of soil moisture were validated by field measured data from Shanghai Geological Survey Academy. The RMSE was 3.62%. This research provided an available and suitable method which could extract soil moisture information by using synthetic aperture radar.