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Raikoke Volcanic Sulfate/SO2 Anticyclonic Contained Circulations: In Situ Proof, Morphology, and Radiative Signature

delete2025-08-29
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PRE
AI
M
Michael Fromm *
G
G. P. Kablick
I
Isabelle A. Taylor
R
R. G. Grainger
C
C. J. Seftor
E
Ellsworth J. Welton
G
Gilberto J. Fochesatto
DOI:10.1029/2024JD041653delete
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Abstract

Abstract

En 中文
We present an analysis of the stratospheric cloud from the June 2019 Raikoke volcanic eruption. The cloud is observationally characterized herein as consisting primarily of SO 2 ${\text{SO}}_{2}$ and sulfuric acid droplets, and marked by multiple distinctive, quasi-circular cloud features ∼ ${\sim} $ 300–400 km in diameter. Previous reports showed that one of these entities was traceable for 3 months. Anticyclonic circulation was also previously reported. We present multiple lines of evidence to characterize these cloud subelements by their spatial confinement, morphology, and sulfate-dominated aerosol aspect, which was evident from plume onset. In addition, we show that they were ably identifiable in geostationary satellite “cirrus channel” reflectance imagery and had an enduring signal of window infrared absorption, detectable for at least 1 month. The term we apply to this phenomenon is “sulfate/SO2 anticyclonic contained circulation,” abbreviated SSACC. Anticyclonic circulation is first detectable on 24 June, 2 days posteruption. Two SSACCs persist beyond June. One is traceable until mid-August over Canada. The other SSACC was discernible until 5 October after having completed three global circumnavigations. The internal SSACC circulation aspect is gleaned from geostationary-based visible image animations and confirmed in situ via a novel application of high-resolution radiosonde wind direction and balloon position data. We also examine diabatic lofting of both SSACCs in relation to their individual geographic and constituent morphologies. Thermal infrared observations show that SSACC aerosols produce brightness temperature depressions of ∼ ${\sim} $ 2.6 K, opening a new line of investigation into the source of heating that contributes to diabatic rise.
Keywords:
stratosphere
vulcanism
aerosol
cloud
sulfate

Journal

J
Journal of Geophysical Research and Atmospheres
IF:
3.4
Papers:
2.2W
Citations:
7.7W

Organization

U
u.s. naval research laboratory
Scholars:
154
Papers: 64
Citations: 0
U
university of alaska
Scholars:
52
Papers: 35
Citations: 0
N
NASA Goddard Space Flight Center
Scholars:
1.0W
Papers: 7.7K
Citations: 16
U
university of oxford
Scholars:
9.6W
Papers: 8.5W
Citations: 137
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