Air-Sea Interaction at Contrasting Sites in the Eastern Tropical Pacific: Mesoscale Variability and Atmospheric Convection at 10 deg N
MASSACHUSETTS INST OF TECH CAMBRIDGE
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The role of ocean dynamics in driving air-sea interaction is examined at two contrasting sites on l25 deg W in the eastern tropical Pacific Ocean using satellite data and data from two air-sea interaction moorings. Analysis reveals marked differences in the role of ocean dynamics in modulating sea surface temperature SST. At a near-equatorial site 3 deg S, the 1997-1998 El Nino event dominated the evolution of SST and surface heat fluxes, and it is found that wind-driven southward Ekman transport was important in the local transition from El Nino to La Nina conditions At a l0 deg N site near the summertime position of the Inter-tropical Convergence Zone, oceanic mesoscale motions played an important role in modulating SST at intraseasonal 50- to 100-day timescales. The characteristics and possible generation mechanisms of this mesoscale variability are examined. Focusing on l0 deg N in the eastern tropical Pacific, the hypothesis that mesoscale oceanic SST variability can systematically influence cloud properties is investigated using several satellite data products. A statistically significant relationship between SST and columnar cloud liquid water and surface solar radiation is identified within the wavenumber-frequency band corresponding to oceanic Rossby waves.