Summer and Autumn Insolation as the Pacemaker of Surface Wind and Precipitation Dynamics Over Tropical Indian Ocean During the Holocene: Insights From Paleoproductivity Records and Paleoclimate Simulations - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Paleoceanography and Paleoclimatology Année : 2024

Summer and Autumn Insolation as the Pacemaker of Surface Wind and Precipitation Dynamics Over Tropical Indian Ocean During the Holocene: Insights From Paleoproductivity Records and Paleoclimate Simulations

Résumé

Abstract Insolation is the engine of monsoon and Walker circulations over the tropical Indian Ocean. Here, we present Holocene coccolith‐related net primary productivity (NPP) signals from two sediment cores retrieved in the wind‐driven coastal upwelling systems off southern India and southern Sumatra. Upwelling‐induced NPP is enhanced during summer and autumn and is a powerful tool to reconstruct atmospheric features at a seasonal scale. Our records indicate that during summer and autumn, westerly winds off southern India strengthened from the early‐Holocene (EH) to late‐Holocene (LH), while southeasterly winds off southern Sumatra strengthened from the EH to mid‐Holocene (MH) and weakened from the MH to LH. Comparisons with previous paleoclimate records and simulations, allow us to confirm such wind patterns at a regional scale and identify distinct atmospheric features associated to insolation before and after the MH. From the EH to MH, as the insolation in the Northern Hemisphere weakens during summer and strengthens during autumn, the equatorial Indian Ocean is characterized by more vigorous Walker and monsoon circulations in summer and autumn, respectively. From the MH to LH, as the insolation weakens in the Northern Hemisphere during summer and over the equator during autumn, the equatorial Indian Ocean is influenced by a general reinforcement of the Walker circulation during both seasons, a feature that we relate to a modern negative IOD‐like mode. The changes in wind result in increasing precipitation over Indonesia and India from EH to MH and over Indonesia from MH to LH as India is getting dryer.
Fichier sous embargo
Fichier sous embargo
0 2 8
Année Mois Jours
Avant la publication
vendredi 5 juillet 2024
Fichier sous embargo
vendredi 5 juillet 2024
Connectez-vous pour demander l'accès au fichier

Dates et versions

hal-04379469 , version 1 (19-03-2024)

Identifiants

Citer

Xinquan Zhou, Stéphanie Duchamp-Alphonse, Franck Bassinot, Chuanlian Liu. Summer and Autumn Insolation as the Pacemaker of Surface Wind and Precipitation Dynamics Over Tropical Indian Ocean During the Holocene: Insights From Paleoproductivity Records and Paleoclimate Simulations. Paleoceanography and Paleoclimatology, 2024, 39 (1), ⟨10.1029/2023PA004786⟩. ⟨hal-04379469⟩
33 Consultations
2 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More