气象卫星亚像元火点面积和亮温估算方法

THE METHOD OF EVALUATING SUB-PIXEL SIZE AND TEMPERATURE OF FIRE SPOT IN AVHRR DATA

该文给出了利用极轨气象卫星AVHRR多个红外通道资料在不同火点强度条件下估算亚像元火点面积和温度的方法 ,包括利用牛顿迭代法求解不同红外波段 (如 :中红外 3.7μm通道和热红外 1 1 μm通道 ,或短波红外 1 .6μm通道和热红外 1 1 μm通道 )混合像元表达式建立的二元非线性方程组 ,得到亚像元火点面积和温度 ;通过建立亚像元火点面积和温度与1 1 μm混合像元亮温增量和 1 1 μm与 1 2 μm混合像元亮温增量差异的关系 ,以查表方式获得对于相同红外波段不同通道 (如 1 1 μm和 1 2 μm通道 )

A method to evaluate the sub-pixel size and temperature of fire spot was presented by using the multiple infrared channel data from polar-orbiting meteorological satellite sensor under various fire spot conditions with the different infrared band data, for example, the mid-band (3.7 μm) and thermal-band (11 μm), or short infrared band (1.6 μm) and thermal-band (11 μm). The Newton's iteration method can be used to find an accurate solution from a dual non-linear coupled equation established by the expression of mixed pixel. For the different channels in the same infrared band, the relationship, between sub-pixel size and temperature of active fire vs the brightness temperature increment of mixed pixel in 11μm channel and difference of brightness temperature increment of mixed pixel in 11μm and 12μm channel, can be established by generating a look up table, and from the table, the evaluating of sub-pixel size and temperature of fire spot can be derived from the brightness temperature of a mixed pixel.