复杂地表条件下冻融土的微波辐射特性模拟及判别分析

Microwave Radiation of Frozen and Thawed Soils under Complicated Surface Condition: Simulation and Discrimination Analysis

针对AMSR-E数据的新特点,在HUT积雪辐射模型的基础上,增加冻土介电模型计算冻融土的介电常数,并使用AIEM模型描述地表的散射特性,建立寒区地表微波辐射模型,对寒区6种典型环境的微波辐射进行了模拟.结果表明:使用36.5 V的亮温以及6.925 H、10.65 H、18.7 H与36.5 V的亮温比分别衡量地表温度和发射率的变化,最能体现地表土壤的冻融变化特征.通过Fisher判别分析,建立了复杂地表条件下的冻融土判别算法,并使用微波辐射计观测数据进行修正.AMSR-E星载数据的验证结果表明,该判别算法能够有效区分较长时间序列和大范围的地表冻融状态,是一种可靠的判别模式.

Frozen soils have strong implications on fresh water hydrology,terrestrial ecology,weather and climatology.In the Watershed Airborne Telemetry Experimental Research(WATER) deployed in March,2008 in the Heihe River basin,continuous observations of the freezing-thawing cycles on typical ground surfaces were carried out at 18.7 and 36.5 GHz by a trunk-mounted microwave radiometer with dual polarizations.The observations are in consistent with the features of AMSR-E data.On the basis of the HUT snow emission mo...