HR: 1340h
AN: A43B-0041    [Abstracts]
TI: Equatorial Atlantic cold tongue variability and its impact on precipitation
AU: * M\"unnich, M
EM: munnich@atmos.ucla.edu
AF: Inst. Geophysics and Planetary Physics at UCLA, 3845 Slichter Hall, Los Angeles, CA 90095-1567 United States
AU: Neelin, D
EM: neelin@atmos.ucla.edu
AF: Inst. Geophysics and Planetary Physics at UCLA, 3845 Slichter Hall, Los Angeles, CA 90095-1567 United States
AB: Rank correlation maps of sea-surface temperature anomalies (SSTA) in the equatorial Atlantic cold tongue (ACT) with precipitation anomalies indicate a strong relationship of precipitation at the margin of the Atlantic ITCZ to ACT SSTA in all seasons. In May, the region of significant rain correlation with ACT reaches into equatorial South America, during July and August Upper Guinea. Using both models and observations we provide evidence for active involvement of equatorial ocean dynamics in ACT variability, with antecedent equatorial wind anomalies in the western Atlantic the likely forcing. A special role for the equatorial region appears to hold despite the strong correlation of equatorial SSTA with SSTA in the southern tropical Atlantic originating from local trade wind variations. An ocean dynamical connection between ACT variability and SSTA variability along the south-eastern Atlantic coast may also exist. Ocean model experiments indicate that ocean dynamics introduces a lag of about one month into the system, which may offer some prospects for forecasting. This must, however, be held in perspective with other known influences on precipitation over the Atlantic ITCZ and tropical South America, including El Nino/Southern Oscillation.
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting