SIMULATION OF THE TROPICAL THERMAL DOMES IN THE ATLANTIC - A SEASONALCYCLE

Citation
T. Yamagata et S. Iizuka, SIMULATION OF THE TROPICAL THERMAL DOMES IN THE ATLANTIC - A SEASONALCYCLE, Journal of physical oceanography, 25(9), 1995, pp. 2129-2140
Citations number
34
Categorie Soggetti
Oceanografhy
ISSN journal
00223670
Volume
25
Issue
9
Year of publication
1995
Pages
2129 - 2140
Database
ISI
SICI code
0022-3670(1995)25:9<2129:SOTTTD>2.0.ZU;2-3
Abstract
A general ocean circulation model is used to analyze seasonal variatio ns in the Guinea Dome and Angola Dome regions. The cold Guinea Dome de velops from June through September due to active divergence of heat tr ansport. The cooling is related to upwelling generated by the local wi nd stress curl associated with the northeast trade winds. The Guinea D ome thus provides an active mechanism of absorbing heat from the atmos phere. The coastal Guinea region experiences semiannual warming in Apr il-July and November-December due to intrusion of coastal downwelling Kelvin waves from the equatorial region. The Angola Dome in the Southe rn Hemisphere is found to be cooled from March through August. The sur face flux plays a major role in the seasonal variation of the heat bud get in contrast to the situation of the Guinea Dome in the Northern He misphere. The Angola front located at the northern border of the cold Angola Dome becomes distinguishable particularly during the boreal fal l because of the intrusion of warm water from the equatorial region. T he coastal warming occurs twice a year in both hemispheres mostly due to intrusion of warm water accumulated in the eastern border of the Gu lf of Guinea. The semiannual relaxation of the trade winds east of 30 degrees W as well as the semiannual intensification of the eastward co mponent of the West African monsoon is responsible for this remarkable oceanic phenomenon.