基于陆面过程模式的热红外卫星遥感影像模拟

遥感服务于气象、气候领域的一个关键环节就是建立地表过程模式与遥感数据之间的联系,利用过程模式的可靠输出参数来模拟卫星影像,并与真实的观测数据进行对比.本文建立了一个以通用陆面过程模式(CLM)相关参数为地表输入信息,以再分析大气廓线为大气输入信息的卫星影像模拟系统,以期通过模拟数据与真实卫星数据的比较,为模式背景场、强迫场的修订及预报精度的提高服务.模拟结果表明,对于由植被和土壤等组成的自然地表,模拟的热红外卫星信号主要取决于过程模式输出的地表温度,模拟的地表方向性辐射温度与模拟的大气层顶部表观辐射温度相关性高达0.99.模拟到的表观辐射温度与AVHRR影像对应的辐射温度差异比较大,最大值超过30 K,大多数像元温差分布在-20～20 K之间.温差在高海拔地区普遍比较大,这可能是由于CLM对高海拔地区的温度估计偏低导致的.

SIMULATION OF THERMAL REMOTE SENSING SYSTEMS BASED ON COMMON LAND MODEL

The combination of remote sensing with the meteorology and climatology makes great progress in recent years.The key point of the combination is to establish the relationship between CLM and the remote sensing data.One important way is to simulate satellite remote sensing images using the output of CLM.It is also helpful to improve CLM itself.This paper reports the simulation of thermal radiation of remote sensing systems based on the CLM and NCEP reanalyzed data.The result shows that the simulation of thermal images is determined by the surface temperature based on CLM,and the correlation coefficient between the directional thermal radiation from ground surface and the effective brightness temperature of simulation reaches 0.996.However,the biggest temperature difference between real AVHRR images and simulations is larger than 30 K,while most of temperature difference is ranging from-10 K to 10 K.The effective brightness temperature of simulation is obviously lower than that of real AVHRR image where DEM is about 5000 m.The main reason is probably the lower brightness temperature from CLM at higher elevation.