Time-of-day/time-of-year response functions of planetary geomagnetic indices Mike Lockwood, Aude Chambodut, Ivan D. Finch, Luke A. Barnard, Mathew J. Owens and Carl Haines J. Space Weather Space Clim., 9 (2019) A20 Published online: 14 June 2019 DOI: 10.1051/swsc/2019017