HR: 08:55h
AN: A41F-04    [Abstracts]
TI: Mechanistic studies of the role of Wind-Evaporation-SST feedback in ocean-atmosphere interaction
AU: * Mahajan, S
EM: salilmahajan@tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843, United States
AU: Saravanan, R
EM: sarava@tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843, United States
AU: Chang, P
EM: ping@ocean.tamu.edu
AF: Department of Oceanography, Texas A&M University, College Station, TX 77843, United States
AB: The Wind-Evaporation-SST (WES) feedback is believed to play an important role in thermodynamic ocean-atmosphere interaction. In the tropical Atlantic, the positive feedback associated with the WES feedback can lead to amplification of the interhemispheric gradient mode variability. It has also been argued that this feedback can communicate high-latitude Atlantic cooling to the tropical Atlantic. In the tropical Pacific, the WES feedback can help explain the propagation of westward propagation of SST anomalies purely through thermodynamic air-sea interaction. However, it is often difficult to conclusively identify the role of the WES feedback using observational analysis, or even by analyzing comprehensive coupled ocean-atmosphere general circulation models (GCMs), because the WES feedback may be masked by other processes. In this study, we report on studies using a modified version of an atmospheric GCM (AGCM), where the WES feedback is deliberately suppressed in the bulk aerodynamic formulation for surface fluxes. By comparing coupled integrations using the modified AGCM to those carried out using the control AGCM, we can focus on the role of the WES feedback. Preliminary results for tropical Atlantic region show that the WES feedback does lead to increased variability, and also helps explain why the ITCZ tends to stay north of the equator.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1626 Global climate models (3337, 4928)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly