Abstract
On the seasonal and interannual migrations of the transition zone chlorophyll front
Pacific Fisheries Environmental Laboratory, NOAA National Marine Fisheries Service, Pacific Grove, California, USA
Joint Institute for Marine and Atmospheric Research, University of Hawaii at Manoa, Honolulu, Hawaii, USA
Pacific Fisheries Environmental Laboratory, NOAA National Marine Fisheries Service, Pacific Grove, California, USA
Pacific Fisheries Environmental Laboratory, NOAA National Marine Fisheries Service, Pacific Grove, California, USA
Pacific Fisheries Environmental Laboratory, NOAA National Marine Fisheries Service, Pacific Grove, California, USA
Pacific Islands Fisheries Science Center, NOAA National Marine Fisheries Service, Honolulu, Hawaii, USA
Pacific Islands Fisheries Science Center, NOAA National Marine Fisheries Service, Honolulu, Hawaii, USA
Pacific Islands Fisheries Science Center, NOAA National Marine Fisheries Service, Honolulu, Hawaii, USA
High-resolution satellite measurements of ocean color and surface winds, along with historical in situ data, are used to explore interannual variability in the annual migration of the transition zone chlorophyll front (TZCF) in the central North Pacific Ocean. Significant variations in frontal position and annual range were observed, including a significant southerly displacement during El Niño events. This displacement, apparently forced by enhanced surface convergence and vertical mixing in the transition zone, creates vast regions of anomalously high wintertime surface chlorophyll in the North Pacific Subtropical Gyre. A remarkably close correspondence between the positions of the TZCF and the 18°C surface isotherm over a portion of the central North Pacific allows historical temperature data to be used as a proxy for TZCF position. This surface temperature proxy has revealed decadal-scale variability in frontal position, with greater (lesser) annual range and southerly extent following the large-scale 1976–77 (1998–99) climate shifts. Interannual variations in TZCF position could have important implications for the distribution and survival of a number of apex predators that utilize the TZCF as a migratory and foraging habitat.
Received 31 May 2004; accepted 9 August 2004; published 2 September 2004.
Citation: (2004), On the seasonal and interannual migrations of the transition zone chlorophyll front, Geophys. Res. Lett., 31, L17204, doi:10.1029/2004GL020637.
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