Fig. 4From: Simulation study of atmosphere–ionosphere variations driven by the eruption of Hunga Tonga-Hunga Ha’apai on 15 January 2022Horizontal wind perturbation obtained by the NHM simulation. a 4:20 UT, b 4:25 UT, c 4:45 UT, and d 5:15 UT. Red color indicates outward from HTHH, and blue color indicates inwardBack to article page