被动微波陆表发射率特性研究

发布时间：2018-03-23 04:16

本文选题：被动微波发射率　切入点：发射率极化差　出处：《辽宁工程技术大学》2013年硕士论文　论文类型：学位论文

【摘要】：地表微波发射率定义为地表向外发射的微波热辐射与同温度的黑体地表向外发射的热辐射的比率,是对地物微波辐射模型理解的关键,也是应用微波数据进行地球物理参数反演的基础。本文在晴空条件下高级微波扫描辐射计(AMSR-E)瞬时发射率产品的基础上,辅助MODIS (Moderate Resolution Imaging Spectroradiometer)的IGBP (International Geosphere-Biosphere Project labels)分类数据提取了不同地物覆盖下半月平均的微波发射率。选取和微波发射率有内在物理联系的卫星产品数据——AMSR-E的微波植被指数(MVIs)、光学MODIS (Moderate Resolution Imaging Spectroradiometer)的归一化植被指数NDVI (Normalized Difference Vegetation Index)、AMSR-E的土壤水分,研究他们和微波发射率之间的内在相关性。结果发现AMSR-E微波发射率和各卫星产品间相关性较高,从而达到简单、快速检验微波发射率的目的。在此基础上结合地表覆盖数据,提取和分析不同植被覆盖和戈壁沙漠的发射率随频率、极化、时间等变化的特性。结果表明,植被发射率在H和V极化均随频率的增加而增加,在有降雪的地区发射率随频率增加而迅速减小。植被区夏季发射率较高,89GHz的V极化发射率值大于0.944,且发射率时间序列上很稳定,极化差较低(0.081),同一地区发射率时间序列RSME小于0.0072。植被区冬季在积雪出现的地方发射率值降低,尤其表现在高频部分。随着植被密度的增加,植被地区发射率值增加而极化差降低。戈壁沙漠区发射率极化差随频率的增加而减小,极化差较大(0.03-0.127)。H极化发射率随频率增加而增加,V极化发射率由于体散射的原因随着频率的增加而减小。37GHz发射率极化差和MODIS的NDVI有很好的负相关性。
[Abstract]:The microwave emissivity of the surface is defined as the ratio of the microwave thermal radiation emitted from the surface to the surface of the blackbody at the same temperature, which is the key to the understanding of the microwave radiation model of the ground object. This paper is based on the instantaneous emissivity of advanced microwave scanning radiometer AMSR-E under clear sky. MODIS moderate Resolution Imaging Spectroradioradiometers) Classification data of IGBP Geosphere-Biosphere Project labels extracted the average microwave emissivity under different ground cover. The selection of satellite product data with inherent physical relationship with microwave emissivity is the microwave vegetation index of AMSR-E. Soil moisture of MODIS moderate Resolution Imaging Spectroradiorometer, a normalized Difference Vegetation index, AMSR-E, is studied. The intrinsic correlation between them and microwave emissivity is studied. The results show that the microwave emissivity of AMSR-E is highly correlated with each satellite product, so that the microwave emissivity can be tested easily and quickly. On this basis, the surface cover data are combined. The characteristics of the emissivity of different vegetation cover and Gobi desert with frequency, polarization and time are analyzed. The results show that the vegetation emissivity increases with the increase of the frequency of H and V polarization. In the region with snowfall, the emissivity decreases rapidly with the increase of frequency. The V polarization emissivity is greater than 0.944 when the emissivity is higher than 89GHz in the vegetation area in summer, and the emissivity time series is very stable. The emissivity time series RSME of the same area is less than 0. 0072. The emissivity value of the vegetation region decreases in winter, especially in the high frequency region, with the increase of vegetation density. The emissivity polarization difference in Gobi desert decreases with the increase of frequency. The polarization emissivity increases with the increase of frequency. The polarization emissivity of V decreases with the increase of frequency and has a good negative correlation with the NDVI of MODIS.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P237

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