Cm. Perigaud et C. Cassou, Importance of oceanic decadal trends and westerly wind bursts for forecasting El Nino, GEOPHYS R L, 27(3), 2000, pp. 389-392
In the western Pacific, Westerly Wind Bursts (WWB) usually show up in the b
oreal fall-winter season, depending on the activity of the Madden and Julli
an oscillation. It is demonstrated with a coupled ocean-atmosphere model th
at WWB have an impact on the coupled system in El Nino forecasting that dep
ends on the ocean preconditioning. Sea level data reveal decadal changes of
the Ocean Heat Content of the entire tropical Pacific (the OHC), with a mi
nimum in the mid-1980s relative to highs before 1982 and after 1996. Adding
the WWB in the forecast system does not degrade the successful predictions
when the OHC is low whereas WWB are necessary in winter 1981-82 and 1996-9
7 to successfully predict the forthcoming warm events. Thus, when the OHC i
s high in addition to the other traditional conditions being favorable for
a warm growth, WWB contribute to having a strong El Nino event the followin
g year.