Downscaling of Tiangong-2 Land Surface Temperature
Tiangong-2 is equipped with a new generation of earth observation instrument, i.e. Wide-band Imaging Spectrometer (WIS), which has a wide range and multiple spatial resolutions with visible and near infrared bands (VNIR, 100 m), shortwave infrared bands (SWIR, 200 m) and thermal infrared bands (TIR, 400 m). It provides the possibility to retrieve land surface temperature (LST) with a 400 m spatial resolution. However, such a spatial resolution limit the applications of TIR spectrum range of WIS in many fields. This study reports the downscaling of LST derived from Tiangong-2 WIS from 400 m to 100 m by utilizing different bands of Tiangong-2 WIS. Specifically, different downscaling methods are compared. Results shows that it is possible to downscale the 400 m LST to a 100 m resolution. Furthermore, the Random Forest (RF) method outperforms the traditional DisTrad method and the Multiple Linear Regression (MLR) method in LST downscaling. The downscaled LST at 100 m can satisfy applications such as the urban heat island monitoring, evapotranspiration calculation and environment modeling.
KeywordsLand surface temperature Downscaling Random Forest Wide-band Imaging Spectrometer (WIS) Tiangong-2
Thanks to China Manned Space Engineering for providing space science and application data products of Tiangong-2. This study is supported by the National Key Research and Development Program of China under grant 2017YFB0503905.
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