HR: 1300h
AN: OS52D-07    [PDF]
TI: Tropical Atlantic Variability Based on PIRATA Buoy Data
AU: * Foltz, G R
EM: gregory.foltz@noaa.gov
AF: NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115 United States
AU: McPhaden, M J
EM: mcphaden@pmel.noaa.gov
AF: NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115 United States
AB: This study examines the causes of intraseasonal and interannual sea surface temperature (SST) anomalies in the tropical Atlantic during 1997 -- 2003. We use in situ measurements from the Pilot Research Array in the Tropical Atlantic (PIRATA) as well as satellite winds and sea surface temperature (SST). Both satellite and buoy data reveal strong interannual oscillations associated with the Atlantic Ni\~no and interhemispheric SST gradient modes, with wind speed and SST anomalies (with respect to the annual cycle) of up to $2\,\,\mathrm{m}\,\,\mathrm{s}^{-1}$ and $1\,^{\circ}\mathrm{C}$, respectively. Examination of the anomalous mixed layer heat balances at two PIRATA buoy locations ($15^{\circ}\mathrm{N},\,\,\mathrm{38}^{\circ}\mathrm{W}$ and $10^{\circ}\mathrm{S},\,\,\mathrm{10}^{\circ}\mathrm{W}$) reveals strong contributions from latent heat loss and shortwave radiation. Wind speed, relative humidity, and SST anomalies all contribute significantly to latent heat loss variability, while shortwave radiation anomalies most likely result from changes in cloud cover. In addition, PIRATA data at $15^{\circ}\mathrm{N},\,\,\mathrm{38}^{\circ}\mathrm{W}$ reveal strong 40 -- 60 day oscillations of wind speed, SST, and precipitation during boreal fall/winter. This period range encompasses the atmospheric Madden-Julian Oscillation, which is known to affect hurricane formation in the Atlantic sector. The intraseasonal wind speed and SST anomalies are associated with anomalous latent heat loss of up to $50\,\,\mathrm{W}\,\,\mathrm{m}^{-2}$ and anomalous mixed layer heat storage of up to $75\,\,\mathrm{W}\,\,\mathrm{m}^{-2}$. Through coupled ocean-atmosphere interactions, these oscillations may play an important role in the evolution of interannual tropical Atlantic SST anomalies.
DE: 1635 Oceans (4203)
DE: 4215 Climate and interannual variability (3309)
DE: 4231 Equatorial oceanography
DE: 4504 Air/sea interactions (0312)
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting