Fig. 2: Evolution of the absolute changes and corresponding top-of-atmosphere (TOA) and near-tropopause instantaneous net radiative forcing (ΔNRF) of three radiatively important stratospheric species perturbed by the Hunga eruption.

Show the evolution of the seasonal mean absolute changes (relative to the reference climatology [CLIM] period) from 2017 until 2023 for: a stratospheric water vapor (SH₂O) concentration, b stratospheric aerosol optical depth (SAOD), c ozone concentration (with 2D-filtered condition), and d ozone concentration (unfiltered, showing values exceeding 2σ above background climatology, UNF). These values are presented for the Southern Hemisphere (SH; blue line), the Northern Hemisphere (NH; gray line), and near-global (60°S–60°N; nGL; red line). Show the clear-sky net (longwave plus shortwave) radiative forcing (ΔNRF) at TOA due to post-eruption perturbations in: e SH₂O, f SAOD, g ozone (2D-filtered; 2DF), and h the combined effect of SH₂O + SAOD + ozone (2D-filtered). i–l show the corresponding dashed blue, gray, and red lines indicate the clear-sky ΔNRF near the tropopause. Dashed cyan lines indicate the horizonal bar near zero in (e–h) and (i–l). Shaded regions represent the interannual standard deviation (1σ) of the background values (except for 2D-filtered ozone, which is extracted above 2σ; see Methods). The perturbations in SH₂O, SAOD, and ozone (2D-filtered) following the eruption exceed their interannual variability, resulting in the combined instantaneous radiative forcing shown in (l).