基于ENVISAT ASAR数据的水稻遥感监测

以江苏省兴化市水稻试验区为例,利用单时相多极化ENVISAT ASAR(Advanced Synthetic Aperture Ra-dar)数据进行水稻识别和生长参数反演。通过分析水稻和其他地物在该时相上的VV极化和HH极化后向散射特征,选择合适的阈值和条件,利用阈值分类算法从影像中提取水稻分布。另外,利用实测水稻生长参数和获取的植被指数(NDVI)数据与水稻后向散射系数进行相关性分析。分析结果表明,水稻VV极化后向散射强度与水稻形态结构、叶面积指数和生物量具有较好的相关性,而水稻HH极化后向散射强度对水稻冠层含水量的变化更敏感。基于上述分析,建立反演水稻株高、叶面积指数和NDVI等参数的关系模型。经过验证,水稻识别精度为84.36%,反演的水稻生长参数的空间变化和实际情形相符合。

Rice Monitoring Based on ENVISAT ASAR Data

Radar remote sensing technology has become an important method for stable and long-time rice monitoring due to its capability to operate in all weather conditions.In this paper,ENVISAT Advanced Synthetic Aperture Radar(ASAR) alternative polarization VV/HH data was used for rice monitoring in rice experimental area in Xinghua city,Jiangsu province.Firstly,a threshold classification algorithm was developed for mapping rice growth area,according to the different characteristics of backscattering coefficients between paddy rice and other land surface objects.Then,relational models were built for retrieving rice growth parameters from ASAR image,a multi-spectral image being used as ancillary data for rice parameters retrieval,based on correlation analysis between backscattering coefficients and field measurements,as expected,the retrieved rice growth parameters were consistent with field measurements.