(Lamont Doherty Earth Observatory, Columbia University, New York, NY)
The Role of Aerosol and Greenhouse Gas Forcing on Asian Monsoon Changes.
Oct 12, 2016 03:30 PM
Oct 12, 2016 04:30 PM
Oct 12, 2016
from 03:30 pm to 04:30 pm
|Where||112 Walker Building|
|Contact Name||Sukyoung Lee|
|Contact Phone||(814) 863-1587|
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In this talk, I will discuss our recent work on the regional climate changes in the historical period due to both the aerosol and greenhouse gas forcing, in particular how these anthropogenic forcing may have impacted the Asian monsoon. While aerosols and greenhouse gases tend to produce opposite sign changes in terms of sea surface temperature and precipitation as previously discussed, the mechanisms by which these changes occur are not entirely symmetric between the two forcing cases. For example, aerosols tend to produce largely dynamical responses in Asian monsoon circulation changes, while greenhouse gas forcing tends to be dominated by the thermodynamic impact through changes in atmospheric moisture content. The circulation changes are relatively weak in the case of GHG forcing. Further analysis using atmospheric GCM with prescribed aerosol and GHG radiative forcing versus those with the prescribed sea surface temperature (SST) warming suggests that the weak circulation changes due to GHG forcing is a result of the cancellation between CO2 radiative forcing and the SST warming. On the other hand, the aerosol radiative forcing tends to dominate the circulation responses to both the fast and slow responses to aerosol. Future changes in Asian monsoon and hurricane intensity as simulated by the CMIP5 models will also be discussed as a comparison to that during the historical period.