Large Amounts of Water Vapor Were Injected into the Stratosphere by the Hunga Tonga–Hunga Ha’apai Volcano Eruption

The Hunga Tonga–Hunga Ha’apai (Tonga) injected only small amount of SO2 into the stratosphere, while our analyses of the Microwave Limb Sounder (MLS) measurements show that a massive amount of water vapor was directly injected into the stratosphere by the Tonga eruption, which is probably due to its submarine volcanic activity. The Tonga eruption injected a total amount of 139 ± 8 Tg of water vapor into the stratosphere and resulted in an increase of 8.9 ± 0.5% in the global stratospheric water vapor. Analyses also show that the uppermost altitude impacted by Tonga reached the 1 hPa level (~47.6 km). Additionally, the maximum hydration region for increased water vapor is at 38–17 hPa (~22.2–27 km), where the water vapor mixing ratio increased by 6–8 ppmv during the three months after the Tonga eruption. The enhanced stratospheric water vapor has great potential to influence the global radiation budget as well as ozone loss.