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地表温度被认为是影响生态系统的关键因子之一,它与许多地表过程有关。目前,热红外卫星遥感技术是获取有关区域和全球尺度地表温度信息的一个有效、可行的手段。针对不同卫星上搭载的热红外传感器,许多学者开展了大量的研究,其中针对单波段热红外的特点(如Landsat TM/ETM+,CBERS和HJ-1B)提出了单通道(或单窗)算法。该类算法需要准确的地表比辐射率和大气参数(如大气水分含量)。这些参数在现实中又很难轻易获得,从而在一定程度上限制了现有算法的应用。针对HJ-1B高回访频率的特点,本文提出了利用多时相影像的时空信息来直接反演地表温度的Multi-Temporal and Spatial Information-Based Single Channel(MTSC),以解决现有算法对地表比辐射率和大气参数的过度依赖性。实例分析结果显示,基于MTSC法由HJ-1B反演得到的地表温度结果与MODIS地表(陆表和海表)温度产品具有很好的空间一致性;HJ-1B的陆表温度结果总体上被高估了约1 K,而海表温度结果总体上被高估了0.5 K;同时,MTSC法得到的HJ-1B地表温度结果具有更好的细节和空间完整性。最后,通过分析和讨论指出了一些可能的完善途径,如相似像元的确定、修改优化求解中的目标函数、参数的自适应初始化等,以便提高MTSC法的反演精度和实用性。
Surface temperature is considered as one of the key factors affecting ecosystems and is associated with many surface processes. At present, thermal infrared satellite remote sensing technology is an effective and feasible means of obtaining surface temperature information on regional and global scales. A great deal of research has been conducted on thermal infrared sensors mounted on different satellites. Single-channel (or single-window) algorithms are proposed for single-band thermal infrared features such as Landsat TM / ETM +, CBERS and HJ-1B. Such algorithms require accurate surface emissivity and atmospheric parameters (such as atmospheric moisture content). In practice, these parameters are hard to obtain easily, which limits the application of the existing algorithms to a certain extent. In view of the characteristics of HJ-1B high-return frequency, this paper proposes Multi-Temporal and Spatial Information-Based Single Channel (MTSC) which can directly retrieve the surface temperature by using the temporal and spatial information of multi-temporal images. Over-dependence of rates and atmospheric parameters. The case study shows that the surface temperature obtained from HJ-1B inversion based on the MTSC method has good spatial consistency with the MODIS surface (land surface and sea surface temperature) products. The HJ-1B land surface temperature results are generally The estimated sea surface temperature is overestimated by about 0.5 K, while the HJ-1B surface temperature obtained by the MTSC method has better detail and spatial integrity. Finally, we point out some possible ways of improvement, such as the determination of similar pixels, the modification of the objective function in the optimization solution and the adaptive initialization of the parameters through analysis and discussion, in order to improve the accuracy and practicability of MTSC inversion.