L. Coy1,2, P. A. Newman1, K.
Wargan1,2, G. Partyka1,2, S.
Strahan1,3, and S. Pawson1
1NASA GSFC, Greenbelt, MD, USA.
2SSAI, Lanham, MD, USA.
3University of Maryland Baltimore County, Baltimore,
MD, USA.
Corresponding author: Lawrence Coy
(lawrence.coy@nasa.gov)
Key Points:
- Extreme perturbations in the stratospheric winds and temperatures are
linked to a volcanic eruption.
- Hunga Tonga-Hunga Ha’apai eruption effects are unique in the
stratospheric record.
- Data assimilation can track temperature and wind perturbations, even
when some physics is missing.
Abstract
The 15 January 2022 eruption of the Hunga Tonga-Hunga Ha’apai underwater
volcano injected a record amount of water directly into the
stratosphere. This study attempts to quantify this impact on the
temperature, as well as the subsequent changes to the stratospheric
circulation, during the months following the eruption based on
reanalysis fields. The extreme nature of the temperature, wind, and
circulation changes are tracked through comparisons of the first six
months of 2022 with the past 42 years. Examination of the data
assimilation process shows that at 20 hPa the thermal observations are
forcing temperatures to cool significantly, compensating for the absence
of the excess stratospheric moisture in the model used for the
reanalysis, resulting in unusually low temperatures. In response to this
cooling the atmosphere adjusts by creating strong westerly winds above
the temperature anomaly and large changes to the downward and poleward
mean meridional circulation.