Fig. 1: Observed enhancement of stratospheric water vapor and the associated simulated instantaneous radiative forcing during 2022 and 2023 following the Hunga eruption.
From: The January 2022 Hunga eruption cooled the southern hemisphere in 2022 and 2023
a, b show the zonal- and annual-mean latitude–altitude variation in the change of the stratospheric water vapor (H₂O) mixing ratio [ppmv] for 2022 and 2023, respectively, relative to the reference climatology (CLIM) period from 2017 to 2021. Contours denote near-zero changes, and the dashed black line represents the tropopause height. c, d show the corresponding vertically integrated changes from the lower stratosphere to the upper stratosphere. e, f show the latitude–altitude distribution of the difference in net (longwave + shortwave) radiative heating rates (∆NRHR; K day⁻¹) of water vapor within the stratosphere between each post-eruption year and the CLIM period. g, h depict changes in near-tropopause net radiative forcing (\({\triangle {NRF}}_{{H}_{2}O}\); W m⁻²) for 2022 and 2023, highlighting perturbations primarily observed near the lowest levels of the lower stratosphere (above the tropopause height). i, j show the changes at the top-of-atmosphere (TOA) net radiative forcing (\({\triangle {NRF}}_{{H}_{2}O}\); W m⁻²) for 2022 and 2023, respectively.
