多极化多角度ASAR数据反演裸露和小麦地表土壤湿度  

Soil moisture inversion using multi-polarization and multi-angle ENVISAT ASAR data in surface soils of bare area and wheat-covered area

作　　者：王军战[1] 鲍艳松[2] 张友静[3] 屈建军[1] 张伟民[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所敦煌戈壁荒漠生态与环境研究站,兰州730000 [2]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [3]河海大学地球科学与工程学院,南京210098

出　　处：《农业工程学报》2010年第6期205-210,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(40701130)

摘　　要：为了更好地监测地表土壤湿度,利用多极化、多角度ASAR-APP影像数据,研究了裸露和小麦地表土壤湿度反演方法。对裸露地表,基于AIEM(advance integral equation model)模型,建立多项式半经验模型反演土壤湿度;对小麦地表,小入射角HH极化ASAR数据与土壤湿度相关性更好,大入射角HH极化ASAR数据与小麦含水率相关性更好。基于水云模型,首先利用大入射角HH极化ASAR数据去除小麦冠层对雷达后向散射的影响,然后利用多角度ASAR数据推导建立小麦地表土壤湿度反演半经验模型;实测数据验证了裸露和小麦地表土壤湿度反演模型的适用性,利用验证数据反演裸露和小麦地表土壤湿度精度(RMSE)分别为3.55%、3.81%。结果表明,该文半经验模型具有较高的反演精度。Soil moisture（Ms）is an important parameter for agricultural,meteorological and hydrographic studies.In order to monitoring soil moisture better,this paper is focused on the Ms estimation methodology based on the multi-polarization and multi-angle advanced synthetic aperture radar（ASAR）data.For the bare soil surface,the inversion model was built based on the simulated data using Advance Integral Equation Model（AIEM）.In a wheat-covered area,the HH polarization backscattering coefficient at a low incidence angle was significantly positively correlated with Ms,however,the HH polarization backscattering coefficient at a high incidence angle was significantly positively correlated with the vegetation water content（Mv）.Mv is an important parameter of the water-cloud model,so the ASAR data at HH polarization and high incidence angle was used to separate the contribution of wheat canopy backscatter coefficient from the total SAR backscatter coefficient.Then a semi-empirical model was developed to estimate Ms in a wheat-covered area based on the multi-angle ASAR data.Validation was performed by the measured data,the precision of Ms estimation for the bare soil surface and the wheat-covered area was 3.55%and 3.81%respectively.The semi-empirical model has a quite good estimation precision.

关 键 词：土壤湿度 后向散射 模型 ASAR 

分 类 号：TP751[自动化与计算机技术—检测技术与自动化装置]