Super-Resolution of SOHO/MDI Magnetograms of Solar Active Regions Using SDO/HMI Data and an Attention-Aided Convolutional Neural Network

Deep learning, which is a subfield of machine learning, has drawn significant interest in recent years. It was originally used in speech recognition (Deng, Hinton, and Kingsbury, 2013), natural language processing (Kastrati et al., 2021), and computer vision (Hu et al., 2018). More recently, it has been applied to astronomy, astrophysics, and solar physics (Liu et al., 2020a; Jiang et al., 2021; Espuña Fontcuberta et al., 2023; Mercea et al., 2023; Scully et al., 2023). Here, we present a new deep-learning method, specifically an attention-aided convolutional neural network (CNN), named SolarCNN, for solar image super-resolution. SolarCNN aims to enhance the quality of line-of-sight (LOS) magnetograms of solar active regions (ARs) collected by the Michelson Doppler Imager (MDI; Scherrer et al., 1995) on board the Solar and Heliospheric Observatory (SOHO; Domingo, Fleck, and Poland, 1995). The ground-truth labels used for training SolarCNN are the LOS magnetograms of the same ARs collected by the Helioseismic and Magnetic Imager (HMI; Schou et al., 2012) on board the Solar Dynamics Observatory (SDO; Pesnell, Thompson, and Chamberlin, 2012). Training and test samples are collected from ARs in the HMI and MDI overlap period, between 1 May 2010 and 11 April 2011. An AR on the solar disk usually consists of one or more sunspots and pores that are formed because of the concentrations of strong magnetic fields.