Impact of the Atlantic Ocean on the multidecadal fluctuation of El Niño–Southern Oscillation–South Asian monsoon relationship in a coupled general circulation model

2010 ◽  
Vol 115 (D17) ◽  
Author(s):  
Wei Chen ◽  
Buwen Dong ◽  
Riyu Lu
Keyword(s):  
Atlantic Ocean ◽  
General Circulation Model ◽  
South Asian ◽  
General Circulation ◽  
Asian Monsoon ◽  
El Nino ◽  
Southern Oscillation ◽  
Circulation Model ◽  
South Asian Monsoon ◽  
Coupled General Circulation Model

scholarly journals On the Role of the African Topography in the South Asian Monsoon

2016 ◽  
Vol 73 (8) ◽  
pp. 3197-3212 ◽  
Author(s):  
Ho-Hsuan Wei ◽  
Simona Bordoni
Keyword(s):  
South Asian ◽  
General Circulation ◽  
Asian Monsoon ◽  
Circulation Model ◽  
Atmospheric Model ◽  
South Asian Monsoon ◽  
The South ◽  
East African Highlands ◽  
Somali Jet

Abstract The Somali jet, a strong low-level cross-equatorial flow concentrated in a narrow longitudinal band near the coast of Somalia, is a key feature of the South Asian monsoon (SAM) circulation. Previous work has emphasized the role of the East African highlands in strengthening and concentrating the jet. However, the fundamental dynamics of the jet remains debated, as does its relation to the SAM precipitation. In this study, numerical experiments with modified topography over Africa are conducted with the GFDL atmospheric model, version 2.1 (AM2.1), general circulation model (GCM) to examine the influence of topography on the Somali jet and the SAM precipitation. It is found that when the African topography is removed, the SAM precipitation moderately increases in spite of a weakening of the cross-equatorial Somali jet. The counterintuitive precipitation increase is related to lower-level cyclonic wind anomalies, and associated meridional moisture convergence, which develop over the Arabian Sea in the absence of the African topography. Potential vorticity (PV) budget analyses along particle trajectories show that this cyclonic anomaly primarily arises because, in the absence of the blocking effect by the African topography and with weaker cross-equatorial flow, air particles originate from higher latitudes with larger background planetary vorticity and thus larger PV.

Sign in / Sign up

Export Citation Format

Share Document