Local Insolation Drives Afro‐Asian Monsoon at Orbital‐Scale in Holocene.

Insolation changes play an important role in driving monsoon changes at orbital time scales. One key issue that has remained outstanding is whether the Asian monsoon is driven by local insolation from the Northern Hemisphere (NH) or remote insolation from the Southern Hemisphere (SH) at orbital band. Here, we perform a set of sensitivity experiments to quantify the impacts of local and remote insolation changes on the Afro‐Asian summer monsoon at 11 ka BP relative to the present. We show that the Afro‐Asian summer monsoon is overwhelmingly driven by the precession induced local insolation change in the tropical‐subtropical NH. The insolation from NH high latitudes also affects the Afro‐Asian summer monsoon. In contrast, the insolation from SH plays a negligible role. Our model experiments support the idea that the Afro‐Asian summer monsoon are driven predominantly by the direct forcing of NH low latitudes summer insolation for the Holocene. Plain Language Summary: The Afro‐Asian summer monsoon response to solar insolation has been studied extensively both in observation evidences and model simulations. However, whether the Afro‐Asian summer monsoon is driven by local insolation from the Northern Hemisphere (NH) and remote insolation from the Southern Hemisphere (SH) still remains an open question. This work, for the first time, systematically isolates local and remote insolation impacts on Afro‐Asian summer monsoon using insolation from 11 ka BP. Our study suggests that the Afro‐Asian summer monsoon is driven by local precession insolation change. The increased local summer insolation at 11 ka increases the land‐sea thermal contrast, migrating the subcloud moist static energy maximum and westerly jet northward. These processes lead to a belt of increased monsoon precipitation stretching from North Africa eastward into South and East Asia, resulting in enhanced monsoon circulation and precipitation. The remote insolation from NH high latitude can also drives the incremental Afro‐Asian summer monsoon precipitation but the magnitude is much smaller compared with local effect. The insolation from SH has negligible role. Our model experiments support the idea that NH summer monsoons are driven predominantly by the direct forcing of NH low latitudes summer insolation for the Holocene. Key Points: The first study to completely isolate the local and remote insolation effect on Afro‐Asian summer monsoon at geological timeThe Afro‐Asian summer monsoon during Holocene is driven by local precession forcing in the tropical‐subtropical Northern HemisphereThe "latent heat" hypothesis is not supported by this study [ABSTRACT FROM AUTHOR]