The experimental Indian Nano-Satellite (INS)-2TD acquires data in a long-wave infrared (7 to 16 μm) region with a fairly good spatial resolution of 175 m. Our study focuses on the retrieval of land surface temperature (LST) using a physics-based generalized single-channel (GSC) algorithm for the INS-2TD observations. A total of 597,240 at-sensor radiance simulations were carried out using moderate resolution atmospheric transmittance 5.3 radiative transfer model for varying conditions pertaining to surface, atmosphere, and sensor geometry to develop and validate the GSC algorithm for broadband INS-2TD sensor. The result from simulated test dataset shows the algorithm’s consistent performance with root-mean-square error (RMSE) of 2.87 K and 0.97 R2. Pixel-to-pixel intercomparison of retrieved LST and standard LST product of Indian National Satellite (INSAT)-3D indicates a good agreement with 0.99 R2 and range of RMSE from 1.17 to 4.78 K over the six selected datasets of South-Asia. The results reveal that the retrieved INS-2TD LST products perform very well, except having a hot bias of around 4.78 K compared to INSAT-3D LST over the Himalayan mountains due to the topographic effect. These results show the overall reasonable accuracy of the retrieved LST over heterogeneous surfaces and highly dynamic atmospheric conditions.

中文翻译：

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使用广义单通道算法从南亚地区 INS-2TD 热红外观测中反演地表温度

实验性印度纳米卫星 (INS)-2TD 采集长波红外（7 至 16 μm）区域的数据，具有 175 m 的相当好的空间分辨率。我们的研究重点是使用基于物理的广义单通道 (GSC) 算法对 INS-2TD 观测进行地表温度 (LST) 反演。使用中等分辨率大气透射率 5.3 辐射传输模型，针对与表面、大气和传感器几何形状相关的不同条件，总共进行了 597,240 次传感器处辐射率模拟，以开发和验证宽带 INS-2TD 传感器的 GSC 算法。模拟测试数据集的结果表明该算法具有一致的性能，均方根误差 (RMSE) 为 2.87 K 和 0.97 R2。检索到的地表温度与印度国家卫星 (INSAT)-3D 的标准地表温度产品的逐像素比对表明，在南亚的六个选定数据集上，R2 为 0.99，RMSE 范围为 1.17 至 4.78 K。结果表明，与 INSAT-3D LST 相比，由于地形效应，在喜马拉雅山脉上空检索的 INS-2TD LST 产品表现良好，但与 INSAT-3D LST 相比存在 4.78 K 左右的热偏差。这些结果表明，在非均匀表面和高度动态的大气条件下反演的地表温度具有总体合理的精度。