HR: 0830h
AN: OS41D-62    [PDF]
TI: Processes Underlying Seasonal Chlorophyll Variability in the Tropical Pacific
AU: * Palomino, E
EM: palomino@mbari.org
AF: MBARI, 7700 Sandholdt Road, Moss Landing, CA 95039-9644 United States
AU: Ryan, J
EM: ryjo@mbari.org
AF: MBARI, 7700 Sandholdt Road, Moss Landing, CA 95039-9644 United States
AU: Strutton, P
EM: stpe@mbari.org
AF: MBARI, 7700 Sandholdt Road, Moss Landing, CA 95039-9644 United States
AU: Chavez, F
EM: chfr@mbari.org
AF: MBARI, 7700 Sandholdt Road, Moss Landing, CA 95039-9644 United States
AU: Chao, Y
EM: yi.chao@jpl.nasa.gov
AF: NASA/JPL, M/S 300-323, Jet Propulsion Laboratory 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Golubev, Y
EM: ygolubev@sdsio.jpl.nasa.gov
AF: Raytheon, 299 N. Euclid Avenue, Suite 500 , Pasadena, CA 91101 United States
AU: Polito, P
EM: polito@ltid.inpe.br
AF: INPE, Av. dos Astronautas 1758 , Sao Jose dos Campos,, SP 12227-010 Brazil
AU: Chai, F
EM: fchai@maine.edu
AF: University of Maine, 5741 Libby Hall, Orono, ME 04469-5741 United States
AB: Since it began operation in September 1997, the SeaWiFS ocean color sensor has observed great variability in surface chlorophyll concentrations in the tropical Pacific. Seasonal variation emerges as an important mode of variation in EOF decomposition of nearly 4 years of monthly mean SeaWiFS chlorophyll between 10{\deg}N and 10{\deg}S. The first EOF mode, describing El Ni\~{n}o, accounts for 41\% of the variance. The second mode, accounting for 15\% of the variance, describes the seasonal cycle that is out of phase between waters on and near the equator (approximately 5{\deg}S to 4{\deg}N) and adjacent waters poleward of this latitude range. Seasonal variability defined by this mode is greatest along and north of the equator. In near-equatorial waters, positive chlorophyll anomalies of the seasonal mode peak during July-September. Poleward of this region, the out-of-phase seasonal chlorophyll anomalies peak during February-April. EOF decomposition of TOPEX sea surface height (SSH) shows similar spatial and temporal variation in the third EOF mode (10\% of the variance) that describes seasonal variability. The relationship between seasonal variation in chlorophyll and SSH defined by EOF decomposition is peak seasonal chlorophyll during minimum seasonal SSH in both regions, consistent with the importance of thermocline depth to nutrient supply to the euphotic zone. Using satellite sea surface height and temperature, scatterometer winds, moored observations from Tropical Atmosphere Ocean (TAO) array, and numerical model simulations of the tropical Pacific using the Regional Ocean Modeling System (ROMS), we examine seasonal and spatial variation in processes influencing euphotic zone nutrient supply from the nutricline.
DE: 4223 Descriptive and regional oceanography
DE: 4227 Diurnal, seasonal, and annual cycles
DE: 4231 Equatorial oceanography
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 4279 Upwelling and convergences
SC: OS
MN: 2002 Ocean Sciences Meeting