Seasonal climatology of wind‐driven circulation on the New Jersey Shelf

Abstract

[1] The spatial structure of the mean and seasonal surface circulation in the central region of the Mid-Atlantic Bight (New Jersey Shelf) are characterized using 6 years of CODAR long-range HF radar data (2002)(2003)(2004)(2005)(2006)(2007). The mean surface flow over the New Jersey Shelf is 2-12 cm/s down shelf and offshore to the south. The detided root-mean-square (RMS) velocity variability ranges from 11 to 20 cm/s. The variability is on the order of the mean current offshore and several times that of the mean current nearshore. The Hudson Shelf Valley and the shelf break act as dynamical boundaries that define the New Jersey Shelf. The surface flow on the New Jersey Shelf depends on topography, seasonal stratification, and wind forcing. The flow is in the approximate direction of the wind during the unstratified season and more to the right of the wind during the stratified season. During the stratified summer season, the dominant along-shore upwelling favorable winds from the SW drive cross-shelf offshore flow. During the unstratified/well-mixed winter season, the dominant cross-shore NW winds drive cross-shelf offshore flows. During the transition seasons of spring and autumn, along-shore NE winds, often associated with storm events, drive energetic down-shelf, along-shelf flows. The surface transport pathways are either cross-shelf dominated during summer and winter or along-shelf dominated during the transition seasons. The residence time of surface Lagrangian drifters on the New Jersey Shelf ranged from 1 to 7 weeks with summer and autumn showing faster transport than winter and spring.

Evaluation of two algorithms for a network of coastal HF radars in the Mid-Atlantic Bight

“…The processing and analysis metrics are consistent with those introduced in Ullman et al (2006) and applied in Gong et al (2010).…”

Ocean observatory data are useful for regional habitat modeling of species with different vertical habitat preferences

“…We speculate that coastal ocean areas impacted by estuarine plumes where upwelling occurs and productivity is high could serve as high quality spawning grounds that place eggs in close proximity to optimal feeding habitats for larvae which are at a lower trophic level of ~3 (Grimes & Kingsford 1996). These same areas also have physical transport mechanisms likely to deliver larvae south and west to important estuarine nurseries (Epifanio & Garvine 2001, Lentz 2008, Tilburg et al 2009, Zhang et al 2009, Gong et al 2010. Spawning habitat selection and suitability should be largely defined by conditions promoting the development, survival and successful transport of early life stages to juvenile nurseries rather than by the immediate requirements of adults.…”

“…Associations of the pelagic species with specific surface flows in our models may have reflected the efficient use of cross shelf transport pathways during seasonal migrations. However, the animals were collected in trawls on the bottom where current flows can be different to seasonally complex surface flows (Lentz 2008, Gong et al 2010. Furthermore, areas with higher velocity, low variance surface flows also tended to have weakly stratified water columns with shallow mixed layers.…”

Ocean–atmosphere dynamics during Hurricane Ida and Nor’Ida: An application of the coupled ocean–atmosphere–wave–sediment transport (COAWST) modeling system

“…The CODAR radial spectra's resolution is dependent on the operating frequency, the sweep rate, and the FFT length used in processing. The CODAR data were processed considering a standard 1 Hz sweep rate, an operating frequency of 4.55 MHz, and a 1024-point FFT, which gives a radial velocity resolution of 3.22 cm s À1 (Gong et al, 2010). The final total vector current map has a spatial resolution of 6 km with a cross-shelf range of 150 km.…”