The impact of stratospheric volcanic aerosol on decadal‐scale climate predictions

Abstract

AbstractTo understand the impact of volcanic aerosol on multiyear seasonal and decadal climate predictions, we performed Coupled Model Intercomparison Project Phase 5‐type hindcasts without volcanic aerosol using the German Mittelfristige Klimaprognosen prediction system and compared them to the corresponding simulations including aerosols. Our results show that volcanic aerosol significantly affects the prediction skill for global mean surface air temperature in the first five years after strong volcanic eruptions. Also, on the regional scale a volcanic imprint on decadal‐scale variability is detectable. Neglecting volcanic aerosol leads to a reduced prediction skill over the tropical and subtropical Atlantic, Indic, and west Pacific but to an improvement over the tropical east Pacific, where the model has in general no skill. Multiseasonal differences in the skill for seasonal mean temperatures are evident over Continental Europe with significant skill loss due to neglection of volcanic aerosol in boreal winter over central Europe, Scandinavia and over southeastern Europe, and the East Mediterranean in boreal summer.