Fig. 3.

Equatorial Pacific response following the Pinatubo eruption. Equatorial Pacific (120 °E–80 °W) clear-sky surface shortwave radiation, relative sea surface temperature (SST), precipitation, zonal wind stress, zonal current and 20 °C isotherm depth (D20) anomalies following the Pinatubo eruption in IPSL-CM5B sensitivity experiments for initial conditions favourable to neutral ENSO state at the end of the eruption year in the unforced control run based on the warm water volume. a Time series of mean tropical (20 °S–20 °N) surface clear-sky shortwave anomalies for IPSL-CM5B. Longitude–time section of 5 °S–5 °N anomalous b relative SST (°C); the dashed black box locates the Niño3.4 (5 °N–5 °S, 170 °W–120 °W) region during November–March; c precipitation (mm day⁻¹) and d zonal wind stress (10⁻² N m⁻²); the dashed black box indicates the region of large-scale westerly wind anomaly in the western Pacific around October of the eruption year, e zonal current integrated over the upper 100 m (cm s⁻¹) and f depth of 20 °C isotherm depth (m) from June of the year of the Pinatubo eruption (year 0) until July 2 years after (year 2). On e eastward current corresponds to positive anomalies. Stippling on b–f indicates time and locations for which at least two thirds of the members display consistent sign anomalies. Contours on b–f indicate anomalies that are significantly different from zero at the 90% confidence level, based on a two-tailed Welch’s t-test