Fig. 3: Robustness of post-volcanic circulation and hydroclimatic anomalies across different internal climate states.
From: Tropical volcanism triggers pan-Asian monsoon droughts via circumglobal teleconnection
a, b Composite anomalies in the first summer after all selected tropical volcanic eruptions. c, d Same as (a, b), but composited over eruptions followed by a negative circumglobal teleconnection (CGT) phase. e, f Same as (a, b), but composited over eruptions followed by a positive CGT phase. g, h Same as (a, b), but restricted to cases with neutral El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) background states. Left panels (a, c, e, g) display 200-hPa meridional wind standardized anomalies (V200; shading). Overlaid black contours denote the climatological summer CGT pattern, defined as the leading empirical orthogonal function (EOF) mode of the ERA5 200-hPa meridional wind (solid and dashed lines indicate positive and negative values, respectively). Right panels (b, d, f, h) display precipitation anomalies (shading, σ) and 850-hPa wind anomalies (vectors). All anomalies are derived from Community Earth System Model–Last Millennium Ensemble (CESM-LME) simulations (1657–2000) relative to a 5-year pre-eruption baseline. Stippling (for shading) and black vectors (for winds) indicate regions where at least 10 out of 13 ensemble members agree on the sign of the anomaly. Numbers in parentheses indicate the total number of events included in each composite.
