Feedback of Tropical Instability-Wave-Induced Atmospheric Variability onto the Ocean

• Published in: Journal of climate Vol. 20; no. 23; pp. 5842 - 5855
• Main Authors: Seo, Hyodae, Jochum, Markus, Murtugudde, Raghu, Miller, Arthur J., Roads, John O.
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.12.2007
• Subjects: Air currents; Atmosphere; Atmospheric boundary layer; Atmospheric effects; Atmospheric models; Atmospheric variability; Atmospherics; Baroclinic instability; Boundary conditions; Budgets; Climate models; Climatic analysis; Damping; Earth, ocean, space; Ekman pumping; Energy; Equatorial currents; Equatorial regions; Exact sciences and technology; External geophysics; Feedback; Heat; Heat flux; Heat transfer; Instability; Instability waves; Instability waves (fluids); Latent heat; Latent heat flux; Meteorology; Nonfiction; Ocean circulation models; Ocean currents; Oceanography; Oceans; Parameterization; Perturbation; Physics of the oceans; Remote sensing systems; Scatterometers; Sea-air exchange processes; South Equatorial Current; Stress; Tropical atmosphere; Waves; Wind; Wind effects; Wind stress; Equatorial Atlantic; Atlantic Ocean; AS, Equatorial Atlantic; ocean currents; Tropical instability wave; Wind effect; Climate models; digital simulation; ocean-atmosphere interaction; Ocean-atmosphere model; feedback; Hindcast; Momentum transfer; ocean waves; wave damping; high resolution
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/jcli4330.1

The effects of atmospheric feedbacks on tropical instability waves (TIWs) in the equatorial Atlantic Ocean are examined using a regional high-resolution coupled climate model. The analysis from a 6-yr hindcast from 1999 to 2004 reveals a negative correlation between TIW-induced wind perturbations and TIW-induced ocean currents, which implies damping of the TIWs. On the other hand, the feedback effect from the modification of Ekman pumping velocity by TIWs is small compared to the contribution to TIW growth by baroclinic instability. Overall, the atmosphere reduces the growth of TIWs by adjusting its wind response to the evolving TIWs. The analysis also shows that including ocean current (mean + TIWs) in the wind stress parameterization reduces the surface stress estimate by 15%–20% over the region of the South Equatorial Current. Moreover, TIW-induced perturbation ocean currents can significantly alter surface stress estimations from scatterometers, especially at TIW frequencies. Finally, the rectification effect from the atmospheric response to TIWs on latent heat flux is small compared to the mean latent heat flux.