Timelines of plume characteristics of the Hunga Tonga-Hunga Ha’apai
eruption sequence from 19 December 2021 to 16 January 2022: Himawari-8
observations
Abstract
The 15 January 2022 shallow water eruption of Hunga Tonga-Hunga Ha’apai
(HTHH) volcano was remarkable, in part, because it produced the highest
plume observed in the advanced satellite era. The Himawari-8
geostationary satellite captured this HTHH eruption well and provides a
unique opportunity to track the evolution (plume and umbrella cloud
height) of a large volcanic eruption through time. The 15 January 2022
eruption was preceded by eruptions in late December 2021 and 13 January
2022, for which we have also assessed plume characteristics. In addition
to umbrella cloud height, we use Himawari-8 data to determine the radial
expansion of the umbrella clouds and volumetric flow rates (VFR). The
altitude of umbrella clouds preceding 15 January 2022 reached
~16-18 km, crossing into the stratosphere. On the day of
the large climactic eruption (15 January 2022), the umbrella clouds
attained a height close to 31 km. We observed two powerful explosive
eruptions on 15 January at an interval of four hours, indicated by the
minimum 11.2μm brightness temperature occurring at 04:10 UTC (172 K) and
08:10 UTC (174 K). On 15 January 2022, beyond 05:30 UTC, the strong
westward propagation of upper umbrella (UB) clouds at
~31 km enabled the visibility of lower umbrella (UA)
clouds at ~18 km. We find that UA is mainly dominant
with ash, whereas UB is dominant with thick ice clouds based on
brightness temperature difference analysis. The satellite-derived VFR
for 15 January 2022 is around 5.00 x 10^11 m3s-1, nearly two orders
of magnitude higher than that estimated on 19 December 2021 and 13
January 2022 eruptions.