1997–1998 El Niño off Peru: A numerical studyстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 29 сентября 2021 г.
Аннотация:An eddy-resolving numerical simulation for the Peru–Chile system between 1993 and 2000 is analyzed,mainly for the 1997–1998 El Niño. Atmospheric and lateral oceanic forcings are realistic and contain awide range of scales from days to interannual. The solution is validated against altimetric observationsand the few in situ observations available. The simulated 1997–1998 El Niño closely resembles the real1997–1998 El Niño in its time sequence of events. The two well-marked, sea-level peaks in May–June andNovember–December 1997 are reproduced with amplitudes close to those observed. Other sub-periodsof the El Niño seem to be captured adequately. Simple dynamical analyses are performed to explain the1997–1998 evolution of the upwelling in the model. The intensity of the upwelling appears to be determinedby an interplay between alongshore, poleward advection (related to coastal trapped waves) andwind intensity, but also by the cross-shore geostrophic flow and distribution of the water masses on ascale of 1000 km or more (involving Rossby waves westward propagation and advection from equatorialcurrents). In particular, the delay of upwelling recovery until fall 1998 (i.e., well after the second El Niñopeak) is partly due to the persistent advection of offshore stratified water toward the coast of Peru. Altimetrydata suggest that these interpretations of the numerical solution also apply to the real ocean.