This work was supported by the National Natural Science Foundation of China ( 41601215 , 41977009 , 41771261 , and 91025018 ), the Natural Science Foundation of Shandong Province, China ( ZR2020QD112 ) and the Fundamental Research Funds for the Central Universities (No. CCNU20QN030 , CCNU20TD008 ). Special thanks go to the staff of the Linze CERN station for their help on field experiments and meteorological data. The authors also thank the anonymous reviewers for their valuable comments.