High-resolution simulation of the global climate and Asian monsoon at 6000 years BP

Abstract

The change in the global climate and the Asian monsoon during the mid-Holocene, 6000 years before present (6ka), is simulated by a high-resolution climate model at spectral truncations of T170, corresponding to grid cell sizes of roughly 75 km. The present simulation was forced with observed monthly sea surface temperatures, and specified atmospheric carbon dioxide concentration, while in the mid-Holocene experiment, orbital parameters (obliquity, precession, and eccentricity) were changed to 6ka. With the 6ka conditions, the precipitation associated with the summer monsoon is enhanced over wider zonal band from the middle-east to Southeast Asia, while in winter precipitation wasn't much altered. The monsoonal wind also increases over the Arabian Sea showing the enhanced southwest wind during the summer and the north east wind during the winter. Overall, the high-resolution simulation captures detailed features of the Asian monsoon and its strength is enhanced during the mid-Holocene, especially in summer, consistent with other previous model simulations.