ENSO suppression due to weakening of the North Atlantic thermohaline circulation
(2005) Journal of Climate — Vol. 18, n° 16, p. 3122-3139 (2005)
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- Changes of the North Atlantic thermohaline circulation (THC) excite wave patterns that readjust the thermocline globally. This paper examines the impact of a freshwater-induced THC shutdown on the depth of the Pacific thermocline and its subsequent modification of the El Niño–Southern Oscillation (ENSO) variability using an intermediate-complexity global coupled atmosphere–ocean–sea ice model and an in- termediate ENSO model, respectively. It is shown by performing a numerical eigenanalysis and transient simulations that a THC shutdown in the North Atlantic goes along with reduced ENSO variability because of a deepening of the zonal mean tropical Pacific thermocline. A transient simulation also exhibits abrupt changes of ENSO behavior, depending on the rate of THC change. The global oceanic wave adjustment mechanism is shown to play a key role also on multidecadal time scales. Simulated multidecadal global sea surface temperature (SST) patterns show a large degree of similarity with previous climate reconstructions, suggesting that the observed pan-oceanic variability on these time scales is brought about by oceanic waves and by atmospheric teleconnections.
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Timmermann, A., An, S.-I., Krebs, U., & Goosse, H. (2005). ENSO suppression due to weakening of the North Atlantic thermohaline circulation. Journal of Climate, 18(16), 3122-3139. https://doi.org/10.1175/JCLI3495.1 (Original work published 2005)