Analysis of the Effect of Enhanced FOV and Sampling Strategy on the Spatial Resolution Enhancement of Spaceborne Microwave Radiometer

Higher spatial resolution can improve the application ability of spaceborne microwave radiometer data. To investigate the capability to enhance the spatial resolution of the radiometer measurements, we analyzed the effect of enhanced field of view (FOV) and sampling strategy on improving spatial resolution using the Backus-Gilbert (BG) method, with the scanning parameters of FengYun-3D Microwave Radiation Imager (MWRI) as an example. The results suggest that selecting an appropriate enhanced FOV and increasing the sampling overlap rate can yield better spatial resolution and effectively reduce the brightness temperature (BT) error that arises from resolution enhancement. As an example, the MWRI 18.7 GHz channel with a spatial resolution of 30 x 50 km is taken. When the spatial resolution of the enhanced FOV is set to 25 x 35 km, compared with other options, the average BT error caused by resolution enhancement is reduced to 0.38 K, and the spatial resolution is improved to 27.3 x 40.5 km. In addition, when the sampling overlap rate of cross-track and along-track directions is set to 91.4% x 92.4%, the highest in the experimental conditions, compared with the original sampling setting, the average BT error caused by resolution enhancement is reduced from 0.72 to 0.4 K, and the spatial resolution is improved to 22.8 x 35.7 km. These experimental findings may provide insights into designing future radiometers and applying the BG method.