Timmermann, A.
An, S.-I.
Krebs, U.
Goosse, Hugues
[UCL]
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.
Bibliographic reference |
Timmermann, A. ; An, S.-I. ; Krebs, U. ; Goosse, Hugues. ENSO suppression due to weakening of the North Atlantic thermohaline circulation. In: Journal of Climate, Vol. 18, no.16, p. 3122-3139 (2005) |
Permanent URL |
http://hdl.handle.net/2078.1/129622 |