HR: 14:25h
AN: A33B-04    [Abstracts]
TI: The Oceanic Aspects of the Remote Influence of ENSO on TAV
AU: * Fang, Y
EM: yfang@ocean.tamu.edu
AF: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77840 United States
AU: Chang, P
EM: ping@tamu.edu
AF: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77840 United States
AB: An anomaly coupled ocean-atmosphere model, consisting of the NCAR CCM3 and a Zebiak-Cane type of reduced gravity ocean model (RGO), is employed to investigate tropical Atlantic response to ENSO remote forcing. A suite of numerical experiments were carried out to assess the relative importance of various oceanic processes contributing to the Atlantic SST response. The result shows that ocean dynamics are required to produce a realistic simulation of the coupled system. It is further shown that the Atlantic response to ENSO can be divided into two stages. Stage one consists of basin-wide SST anomaly which lags ENSO by about a season and peaks in the boreal spring. This response can be largely explained by the ocean mixed layer response to changes in surface heat fluxes induced by ENSO, and is less affected by ocean dynamics. Stage two consists of a cross-equatorial SST anomaly which develops in the late spring and early summer. This response is affected strongly by ocean dynamics. The experiments show that entrainment dynamics are particularly important for maintaining the correct SST structure. Without entrainment the simulated equatorial SST anomaly tends to have the opposite sign of the observed SST. In constrast, the horizontal heat advection appears to be less important and mainly acts to broaden the structure of the SST anomaly.
DE: 4215 Climate and interannual variability (3309)
DE: 4504 Air/sea interactions (0312)
DE: 4522 El Ni¤o
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting