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Feedback of Atmosphere‐Ocean Coupling on Shifts of the Intertropical Convergence Zone
Author(s) -
Schneider Tapio
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075817
Subject(s) - intertropical convergence zone , equator , atmosphere (unit) , atmospheric sciences , energy flux , environmental science , climatology , atmospheric electricity , convergence zone , energy balance , flux (metallurgy) , perturbation (astronomy) , atmospheric model , latitude , geology , meteorology , physics , geodesy , chemistry , precipitation , organic chemistry , quantum mechanics , astronomy , electric field , thermodynamics
It is well known that the Intertropical Convergence Zone (ITCZ) shifts in response to remote perturbations in the atmospheric energy balance, with shifts roughly in proportion to changes in the cross‐equatorial atmospheric energy flux. However, atmospheric and oceanic energy fluxes in low latitudes are mechanically coupled, and the oceanic energy flux dominates the atmospheric energy flux. Here a quantitative framework is derived that shows how Ekman coupling of atmospheric and oceanic energy fluxes damps the perturbation response of the atmospheric energy flux, energy flux equator (EFE), and ITCZ. To first order, Ekman coupling alone mutes the response of EFE and ITCZ in the coupled atmosphere‐ocean system by a factor γ = 1+ O 0 /NEI 0 , where O 0 is the ocean energy uptake and NEI 0 is the net energy input into the atmosphere at the equator. In the current climate in the zonal and annual mean, this factor is about γ ≈3.