SPATIAL COHERENCE OF INTERANNUAL VARIABILITY IN WATER PROPERTIES ON THE US NORTHEAST SHELF

Interannual variability in the surface and bottom temperature and sali nity on the U.S. northeast shelf is described by using hydrographic da ta from the Northeast Fisheries Science Center (NEFSC) MARMAP program. This 10 year data set provides the spatial resolution to describe spa tial patterns in the variability of the shelf water properties. An emp irical orthogonal function analysis is used to determine the primary m odes df variability. All parameters investigated have significant firs t modes, which contain 40-50% of the variance in the winter and 25-35% in the summer period. All parameters, except the summer surface tempe rature, exhibit coherent variability across the entire shelf region fr om near Cape Hatteras to the central Gulf of Maine. The summer surface temperature appears to have two regions of coherent variability: in t he central Middle Atlantic Eight and in the western Gulf of Maine. Thi s regionalization is believed due to the effect of local sources of co astal runoff.