Spatial Resolution Enhancement of Microwave Radiation Imager (MWRI) Data

A spaceborne microwave radiometer has a low spatial resolution limited by its antenna size. Enhancing the spatial resolution of data acquired by such sensors can improve the quality of subsequent applications. To improve the spatial resolution of the Microwave Radiation Imager (MWRI) onboard the Fengyun 3D satellite, this study used a Scatterometer Image Reconstruction (SIR) algorithm to generate resolution-enhanced swath brightness temperature data based on redundant information from overlaps between scanning points. These swath data have a higher pixel resolution that can reach 1/4 of the sampling frequency. The quality of reconstructed images, evaluated through visual comparison and quantitative analysis, revealed reasonable potential for providing more detailed depictions of surface information. Statistical analysis revealed a lower root mean square deviation of 0.8 K and a bias of 0.04 K following the SIR process. Analysis of the pixel spatial response function confirmed that the enhanced data have substantially finer spatial resolution than that of Level-1 data for 10–89 GHz vertical/horizontal channels, with an improvement of 9–39% in effective resolution. The findings of this study show that the SIR algorithm has potential for enhancing the quality of MWRI data and for widening the application domain to satellite product development, satellite data assimilation for numerical weather prediction, and other related fields.