Volcanic-induced global monsoon drying modulated by diverse El Niño responses

Seungmok Paik (1) , Seung-Ki Min (1) , Carley Iles (2) , Erich Fischer (3) , Andrew Schurer (4)

1 POSTECH - Pohang University of Science and Technology
2 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
3 ETH Zürich - Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich]
4 School of Geosciences [Edinburgh]

There remains large intersimulation spread in the hydrologic responses to tropical volcanic eruptions, and identifying the sources of diverse responses has important implications for assessing the side effects of solar geoengineering and improving decadal predictions. Here, we show that the intersimulation spread in the global monsoon drying response strongly relates to diverse El Niño responses to tropical eruptions. Most of the coupled climate models simulate El Niño-like equatorial eastern Pacific warming after volcanic eruptions but with different amplitudes, which drive a large spread of summer monsoon weakening and corresponding precipitation reduction. Two factors are further identified for the diverse El Niño responses. Different volcanic forcings induce systematic differences in the Maritime Continent drying and subsequent westerly winds over equatorial western Pacific, varying El Niño intensity. The internally generated warm water volume over the equatorial western Pacific in the pre-eruption month also contributes to the diverse El Niño development.

Domaines: Océan, Atmosphère; Climatologie

Seungmok Paik, Seung-Ki Min, Carley Iles, Erich Fischer, Andrew Schurer. Volcanic-induced global monsoon drying modulated by diverse El Niño responses. Science Advances , 2020, 6 (21), pp.eaba1212. ⟨10.1126/sciadv.aba1212⟩. ⟨hal-02881722⟩