A Deep-Learning Framework for Super Resolution Reconstruction of SOHO/MDI Magnetograms
摘要
Reconstructing fine-scale magnetic structure from legacy SOHO/MDI magnetograms is essential for extending reliable photospheric diagnostics to periods predating SDO/HMI. We introduce Resolution Enhancement of Solar Magnetogram (RESM), a novel deep-learning framework designed to enhance MDI magnetograms by integrating Feature Enhancement Blocks (FEB) with a Convolutional Block Attention Module (CBAM) to recover compact magnetic concentrations and polarity-inversion structure selectively. RESM achieves strong agreement with HMI, yielding PSNR of 55.6 dB, SSIM of 0.948, PCC of 0.929, and RMSE (G) of 0.071 G compared to state-of-the-art techniques. Physics-aware assessment further shows that RESM preserves multiscale spectral power, maintains signed and unsigned flux budgets, and reproduces coherent PIL contours with high spatial fidelity. A case study of NOAA AR 11131 confirms improved recovery of compact flux bundles and refined PIL topology relative to MDI, enhancing the interpretability of archived observations for active-region characterisation and pre-eruption analysis. These results demonstrate that RESM provides reliable, physically consistent reconstructions of historical magnetograms, expanding their scientific utility.