@article{bignami_hopkins_2003, title={Salt and heat trends in the shelf waters of the southern Middle-Atlantic Bight}, volume={23}, ISSN={["0278-4343"]}, DOI={10.1016/S0278-4343(03)00023-2}, abstractNote={Abstract This work reports on the evolution of water masses within the southern portion of the Middle-Atlantic Bight (MAB) and their exchange with the slope waters based upon the Ocean Margins Program hydrographic dataset (February–October 1996). Water mass distributions were quantified in terms of their content of freshwater and of Gulf Stream Water, with the Cold Pool Water (CPW) as the core shelf water. The CPW entered the area during the early spring, migrated offshore during the early summer and disappeared by early fall. An analysis of the salt and heat balance was estimated from the observed data, extended over an annual cycle. Surface heat and evaporative exchanges were obtained using an atmospheric Eta-coordinate model. This analysis supported the concept that the southernmost portion of the MAB circulates more as a positive estuary, exchanging with the slope waters, than as a shelf conduit exporting MAB waters to the Southern Atlantic Bight. Thus, the primary disposition of the shelf waters, entering the SMAB from the north, is in an offshore surface flow. This offshore flow requires, in turn, a sub-surface onshore flow. Significantly, the type of estuarine circulation switches during the year. During the stratified period, the circulation was analogous to that of a ‘highly stratified’ estuary; during the unstratified period, it resembled that of a ‘well-mixed’ estuary. The important difference between these two modes is that the winter exchange is enhanced, relative to that during the summer period; for example, the offshore flow increased from 2.8 to 3.4 10 5  m s −1 and the onshore flow from 0.44 to 1.0 10 5  m s −1 , respectively. It is suggested that the enhanced exchange is linked to the reduced density gradients, in both the vertical and horizontal, characteristic of the winter convective season. The slower exchange during summer favored freshwater retention in the SMAB volume, with salinities decreasing by 2 psu over the period; the shorter, more intense exchange during the winter favored freshwater loss (salting). In addition to providing salt, the onshore flow brought enough heat to dominate the heat budgets; for example, the advective heat gain increased from 46 to 135 W m −2 , between the summer and winter periods. With regard to the OMP objectives, these results suggest a significantly enhanced potential for carbon loss off the shelf during the winter period, compared to that of summer.}, number={6}, journal={CONTINENTAL SHELF RESEARCH}, author={Bignami, F and Hopkins, TS}, year={2003}, month={Apr}, pages={647–667} }
 @article{grothues_cowen_pietrafesa_bignami_weatherly_flagg_2002, title={Flux of larval fish around Cape Hatteras}, volume={47}, ISSN={["0024-3590"]}, DOI={10.4319/lo.2002.47.1.0165}, abstractNote={Convergence of shelf water flows from the Middle and South Atlantic Bights (MAB and SAB) upon Cape Hatteras, North Carolina, presents a potential barrier to the exchange of fish larvae between bights. Impinging water often turns northeastward with the Gulf Stream, and larvae of both cool temperate and warm temperate/subtropical shelf fishes suffer expatriation. Transient oceanographic features exist, however, facilitating shelf retention, cross‐bight exchange, and return of expatriated larvae. The impact of these features is mitigated by specific distribution with relation to hydrography, resulting in a selective permeability of this barrier. Dynamic oceanography may result in dynamic recruitment success. We measured the springtime (1996) flux of seven larval fish species assemblages across the confluence by coupling measured water mass/depth specific larval fish concentration with water mass transport values obtained from an extensive moored instrument survey. Strong flows of shallow shelf water from the MAB to the SAB dominated transport of MAB spawned larvae even for groups with highest concentrations in waters without strong net flows. Most of these larvae passed from the MAB or the open sea into the study region shelf and from there into the SAB. Net flow of SAB water into the convergence retained SAB‐affiliated larvae arriving from the south, but nearshore MAB flows transported low numbers from the MAB to the SAB. The importance of this is tied to the unknown point of introduction of these SAB larvae to MAB waters (e.g., well north of the confluence), but northward exchange of SAB‐spawned fish was always prevented along the southern MAB shelf.}, number={1}, journal={LIMNOLOGY AND OCEANOGRAPHY}, author={Grothues, TM and Cowen, RK and Pietrafesa, LJ and Bignami, F and Weatherly, GL and Flagg, CN}, year={2002}, month={Jan}, pages={165–175} }