Session: Last Millennium & Past2K
Author: Wenmin Man / email@example.com / LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences
Co-author: Tianjun Zhou, LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences;
We examine the global monsoon (GM) precipitation response to volcanic eruptions in the CMIP5 past1000 simulations. The spatial patterns of precipitation exhibit drying in the monsoon regions in their respective warm season for years 1 and 2 combined following volcanic eruptions. The cooling in the western Paciﬁc is much stronger than that in the eastern Pacific. This zonal SST gradient across the Paciﬁc induces lowering SLP in the EP where the two subtropical Highs straddle the equator. This will weaken the trades which transports and converges moisture into the eastern hemisphere monsoon regions, thereby leading to the reduced GM precipitation. The ‘‘cold land-warm ocean’’ and ‘‘cold NH-warm SH’’ mechanisms can also explain why the NH monsoon has a strong reduction, while only the ‘‘cold land-warm ocean’’ lead to a weak SH monsoon. The summer monsoon rainfall shows a general decreasing anomaly across the majority of the regional monsoon regions. In contrast to a weakened global summer monsoon precipitation, most arid and semiarid desert regions, located to the west and poleward of each monsoon region, show wetting anomalies. The water budget analysis indicate that the change of the dynamic and thermodynamic terms equivalently dominate the change of precipitation.