Signature of intraseasonal oscillations during Hunga Tonga volcanic eruption

The Hunga Tonga–Hunga Ha’apai (HTHH) volcanic (20.536°S, 175.382°W) eruption, took place on 15 January 2022, is one of the most powerful events ever recorded, generating a broad spectrum of atmospheric disturbances. The present study investigates the eruption impact on the Intraseasonal Oscillations (ISO) using satellite and reanalysis data. Wavelet analysis of Outgoing Longwave Radiation (OLR), Precipitation amount (RF), and Specific Humidity (SH) at the volcano location reveals enhanced intraseasonal variability in the period range 20–40 days. Estimated phase speeds obtained from the filtered profiles are found to be 3.6 m/s (OLR), 2.8 m/s (RF), and 3.7 m/s (SH) with eastward propagation direction. Despite strong ISO signature in OLR, RF, and SH, the zonal wind (U) shows no evident response to the event, indicating a possible decoupling of convection and wind. Investigation of the Solar F10.7 flux around the eruption time suggests no clear impact of the solar variability on the observed 20–40 day oscillations. An appreciable signature of the intra-seasonal period is observed in the DE3 (eastward-propagating diurnal tide with zonal wavenumber 3) amplitude in the lower stratosphere, indicating that the event influenced local convective activity and associated wave. Our present findings provide a novel perspective on how extreme volcanic events can impact the atmospheric wave dynamics of varying periods, offering valuable insights into atmospheric response to such powerful event.