Measurements of Stratospheric Water Vapor at Mauna Loa and the Effect of
the Hunga Tonga Eruption
The eruption of Hunga Tonga in January 2022 injected an amount of water
vapor into the stratosphere that is unprecedented in the satellite era.
In the ensuing months Aura Microwave Limb Sounder (MLS) measurements
showed that this plume of water vapor spread from its original injection
site at 20.5⁰S to Mauna Loa, Hawaii at 19.5⁰N, where an increase was
observed in April by the ground-based Water Vapor Millimeter-wave
Spectrometer (WVMS) instruments. Interannual variations in water vapor
occur over Mauna Loa due to both dynamical variations in the tropical
stratosphere and variations in the amount of water vapor crossing the
tropical tropopause, and we place the observed stratospheric water vapor
increase from Hunga Tonga into context of these other variations that
have been observed since 2013.