|
|||||
|
|
Simulated impacts of the South Atlantic Ocean Dipole on summer precipitation at the Guinea Coast |
|
| Authors: | Hyacinth C Nnamchi Jianping Li In-Sik Kang Fred Kucharski |
| Institution: | 1. State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China 2. Graduate University of the Chinese Academy of Sciences, Beijing, China 3. School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea 4. Earth System Physics Section, Abdus Salam International Center for Theoretical Physics, Trieste, Italy |
| Abstract: | An intermediate complexity atmospheric general circulation model has been used to investigate the influence of the South Atlantic Ocean (SAO) dipole (SAOD) on summer precipitation over the Guinea Coast of West Africa. Two ensemble integrations in which idealized but realistic SAOD-type sea surface temperature (SST) anomaly is prescribed only in the SAO, and then globally are performed and inter-compared. Consistently, above (below) the average precipitation is simulated over the Guinea Coast during the positive (negative) phase of the SAOD. Comparison of the two set of experiments reveal that in its active years, the SAOD is a dominant mechanism that shapes the spatial character of summer precipitation at the Guinea coast, the global SST variability merely slightly moderate its effects. During the SAOD, cool SST anomaly in the extra-tropical SAO off the Brazil–Uruguay–Argentina coast gives rise to suppressed convection and mass divergence. In turn, the subsidence tends to amplify the sub-tropical arm of anomalous Hadley-type circulation and consequently large scale convection and mass flux convergence in the equatorial Atlantic Ocean/Gulf of Guinea region bordering on the coastal fringes of West Africa. Precipitation is therefore increased at the Guinea Coast. |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ | |