HR: 16:35h
AN: GC54B-04 INVITED    [Abstracts]
TI: North Pacific Gyres Oscillation: a tropical source of ocean climate and ecosystem change
AU: * Di Lorenzo, E
EM: edl@gatech.edu
AF: Georgia Tech, School of Earth and Atmospheric Sciences 311 Ferst Drive, Atlanta, GA 30306, United States
AU: Schneider, N
EM: nschneid@hawaii.edu
AF: University of Hawaii, 2International Pacific Research Center and Dept. of Oceanography, Honolulu, HI 96816, United States
AB: Decadal fluctuations of salinity and key biological variables in the Northeast Pacific Ocean over the past 50 years have been well documented and are thought to be related to climate change. Dramatic fluctuations in salinity, nutrients, chlorophyll, zooplankton biomass, fish stocks and seabirds, however, are often poorly correlated with the most widely used index of large scale climate variability in the region, the Pacific Decadal Oscillation (PDO). Here we define a new index of climate change, the North Pacific Gyres Oscillation (NPGO) and show that it is significantly correlated with previously unexplained fluctuations of salinity, nutrients and chlorophyll. Fluctuations in the NPGO are teleconnected from the tropics and forced by regional and basin-scale variations in wind-driven upwelling and horizontal advection - the fundamental processes controlling salinity and nutrient concentrations. Nutrient fluctuations drive concomitant changes in phytoplankton concentrations, and may force similar variability in higher trophic levels. The NPGO thus provides a strong indicator of fluctuations in the mechanisms driving planktonic ecosystem dynamics. Observations and global warming simulations show the NPGO amplitude to be increasing over the last 50 years; we expect the dynamics underlying the NPGO to play increasingly dominant roles in forcing decadal changes in marine ecosystems.
UR: http://iManu.Org/npgo
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4516 Eastern boundary currents
DE: 4805 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting