Anomalies of O3, CO, C2H2, H2CO, and C2H6 detected with multiple ground-based Fourier-transform infrared spectrometers and assessed with model simulation in 2020: COVID-19 lockdowns versus natural variability

B. Gaubert, J.W. Hannigan, G. Brasseur, H.M. Worden, T. Blumenstock, H. Fu, F. Hase, P. Jeseck, N. Jones, C. Liu, E. Mahieu, I. Morino, I. Murata, J. Notholt, M. Palm, A. Röhling, Y. Té, K. Strong, Y. Sun, S. Yamanouchi