Yan Huan-Huan, Li Xiao-Jing, Zhang Xing-Ying, Wang Wei-He, Chen Liang-Fu, Zhang Mei-Gen, Xu Jin. Comparison and validation of band residual difference algorithm and principal component analysis algorithm for retrievals of atmospheric SO2 columns from satellite observationsJ. Acta Physica Sinica, 2016, 65(8): 084204. DOI: 10.7498/aps.65.084204