School of Engineering, University of Basilicata, 85100 Potenza, Italy.
ONERA, The French Aerospace Lab, 2 avenue Edouard Belin, 31055 Toulouse Cedex, France.
Sensors (Basel). 2019 Mar 29;19(7):1532. doi: 10.3390/s19071532.
Timely processing of observations from multi-spectral imagers, such as SEVIRI (Spinning Enhanced Visible and Infrared Imager), largely depends on fast radiative transfer calculations. This paper mostly concerns the development and implementation of a new forward model for SEVIRI to be applied to real time processing of infrared radiances. The new radiative transfer model improves computational time by a factor of ≈7 compared to the previous versions and makes it possible to process SEVIRI data at nearly real time. The new forward model has been applied for the retrieval of surface parameters. Although the scheme can be applied for the simultaneous retrieval of temperature and emissivity, the paper mostly focuses on emissivity. The inverse scheme relies on a Kalman filter approach, which allows us to exploit a sequential processing of SEVIRI observations. Based on the new forward model, the paper also presents a validation retrieval performed with in situ observations acquired during a field experiment carried out in 2017 at Gobabeb (Namib desert) validation station. Furthermore, a comparison with IASI (Infrared Atmospheric Sounder Interferometer) emissivity retrievals has been performed as well. It has been found that the retrieved emissivities are in good agreement with each other and with in situ observations, i.e., average differences are generally well below 0.01.
多光谱成像仪（如 SEVIRI（旋转增强可见和红外成像仪））的观测结果的及时处理在很大程度上取决于快速辐射传输计算。本文主要关注为应用于红外辐射的实时处理而开发和实施 SEVIRI 的新正向模型。与以前的版本相比，新的辐射传输模型将计算时间提高了约 7 倍，从而使 SEVIRI 数据能够接近实时处理。新的正向模型已应用于地表参数的反演。虽然该方案可用于同时反演温度和发射率，但本文主要侧重于发射率。逆方案依赖于卡尔曼滤波方法，这使我们能够利用 SEVIRI 观测的顺序处理。基于新的正向模型，本文还展示了在 2017 年在纳米布沙漠的 Gobabeb 验证站进行的现场实验中利用现场观测进行的验证检索。此外，还与 IASI（红外大气探测器干涉仪）的发射率检索进行了比较。结果发现，检索到的发射率彼此之间以及与现场观测值非常吻合，即平均差异通常远低于 0.01。
