HR: 10:40h
AN: A52B-03    [Abstracts]
TI: Sensitivity of Tropical Atlantic Sea-Surface Temperature Variability to Changes in the Atlantic Meridional Overturning Circulation
AU: * Wen, C
EM: caihong@neo.tamu.edu
AF: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843-3146, United States
AU: Chang, P
EM: ping@tamu.edu
AF: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843-3146, United States
AB: Coupled climate model simulations suggest that a slow-down in the Atlantic Meridional Overturning Circulation (MOC) can cause a substantial change in tropical Atlantic sea-surface temperature (SST) variability. However, it is still not clear how the underlying dynamics work in linking the MOC change to the tropics. In this study, we use a reduced gravity ocean model to examine the sensitivity of the tropical Atlantic SST variability to changes in the MOC strength by systematically varying the imposed constant northward mass transport at the open boundaries from 14 SV to 0 SV. The results show that the tropical Atlantic SST responds nonlinearly to changes in the MOC strength. A prominent equatorial warming occurs when the MOC is weakened below a threshold value. This nonlinear behavior is attributed to an interaction between the Atlantic thermohaline circulation and the wind driven subtropical cells. A dynamic mechanism is proposed to explain how the MOC change can affect coupled climate variability in the tropical Atlantic sector.
DE: 0429 Climate dynamics (1620)
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting