Physical dynamics and biological implications of Cyclone Noah in the lee of Hawai’i during E-Flux I

摘要: Abstract Quasi-synoptic observations of the horizontal and vertical structure a cold-core cyclonic mesoscale eddy feature (Cyclone Noah) were conducted in lee Hawai’i from November 4–22, 2004 as part E-Flux interdisciplinary collaborative research program. Cyclone Noah appears to have spun up southwest ‘Alenuihaha Channel (between Maui Hawai’i) result strong persistent northeasterly trade winds through channel. Shipboard hydrographic surveys 2.5 months later suggest that weakened was hypothesized spin-down phase its life cycle. Although initial surface expression limited scale ∼40 km diameter and, evidenced by temperatures, 2–3 °C cooler than surrounding waters, depth profiles revealed fully developed semi-elliptical shallow (∼200 m), ∼144 km long ∼90 km wide (based on sigma-t=23 kg m−3) with tangential speeds 40–80 cm s−1, substantial isopycnal doming. Potential vorticity distribution suggests radial flow core water inhibited depths ∼75 m, high confined above sigma-t=23.5 kg m−3 surface. Upward displacements surfaces eddy's center (∼50 m) congruent enhanced pigment concentrations (0.50 mg m−3). Comparisons results obtained for I (Noah) III (Opal) translation characteristics Hawaiian eddies may be important establishing biogeochemical biological responses oligotrophic ocean eddies.