Malcolm J. Bowman

Proceedings of the Workshop

A universal, concise definition of an oceanic front is difficult to set down. Rather, the nature of fronts are best perceived through a community of characteristics.

Rim current and coastal eddy mechanisms in an eddy resolving Black Sea general circulation model.

Abstract The DieCAST ocean model is applied to a study of the circulation in the Black Sea, using 1/12° horizontal resolution and with 20 vertical layers. Boundary forcings are monthly wind stress, evaporation minus precipitation, air–sea heat flux, freshwater influx from 11 rivers and exchange with the Mediterranean Sea through the Bosphorus Strait. The model reproduces fundamental physical features of the Black Sea: seasonal fluctuations in the quasi-permanent cyclonic Rim Current, numerous anticyclonic meanders and eddies lying between the Rim Current and the coast, Rossby waves propagating westward across the basin, coastally trapped waves, and the annual cycle of vertical mixing. Model results shed light on the mechanisms affecting such features. These include interactions of the Rim Current with coastal bathymetry abutments, leading to recirculations that pinch off vortices as in island wakes, and possible baroclinic instability of the Rim Current; these are modulated by the large annual stratification cycle above a relatively shallow and strong pycnocline, as is the Rim Current itself. The resulting wake eddies often merge into major coastal circulation features such as the seasonal Batumi and Sevastopol eddies. These anticyclonic eddies play a fundamental role in coastal and open-sea exchange processes. Hydrographic data from sampling cruises and recent Topex–Poseiden (T/P) altimeter data strongly supports our analysis.

Tidal mixing and plankton dynamics

Phytoplankton Responses to Vertical Tidal Mixing.- Island Stirring Effects on Phytoplankton Growth.- Patterns of Phytoplankton Production Around the Galapagos Islands.- The Stimulation of Phytoplankton Production on the Continental Shelf within Von Karman Vortex Streets.- Dynamics of Phytoplankton Patches on Nantucket Shoals: an Experiment Involving Aircraft, Ships and Buoys.- The Influence of Tidal Mixing on the Timing of the Spring Phytoplankton Development in the Southern Bight of the North Sea, the English Channel and on the Northern Armorican Shelf.- Are Red Tides Correlated to Spring-Neap Tidal Mixing?: Use of a Historical Record to Test Mechanisms Responsible for Dinoflagellate Blooms.- Tidal Stirring vs. Stratification: Microalgal Dynamics with Special Reference to Cyst-Forming, Toxin Producing Dinoflagellates.- Dynamics of Larval Herring (ClupeaHarengus L.) Production in Tidally Mixed Waters of the Eastern Coastal Gulf of Maine.- The Importance of Bathymetry to Seasonal Plankton Blooms in Hecate Strait, B.C.- The Effects of Seasonal Variations in Stratification on Plankton Dynamics in Long Island Sound.- Observations of the Structure of Chlorophyll A in Central Long Island Sound.- Phytoplankton Patchiness in the Central Long Island Sound.- Empirical Models of Stratification Variation in the York River Estuary, Virginia, USA.- Temporal and Spatial Sequencing of Destratification in a Coastal Plain Estuary.- Effects of Tidal Mixing on the Plankton and Benthos of Estuarine Regions of the Bay of Fundy.- Real-Time Characterization of Individual Marine Particles at Sea: Flow Cytometry.- Development of a Moored in Situ Fluorometer for Phytoplankton Studies.- An Inexpensive Moored Water Sampler for Investigating Chemical Variability.- An Induced Mixing Experiment?.

Bioconcentration of chlorinated hydrocarbons from sediment by oligochaetes

Previously published data on the accumulation of 15 chlorinated hydrocarbons from sediment by oligochaetes have been interpreted on the basis of bioconcentration from interstitial water. Calculation of the interstitial water concentration allowed determination of uptake and clearance rate constants together with bioconcentration factors (KB) for these compounds. These three factors each exhibited a systematic relationship to the octanol/water partition coefficient (KOW). The log KB versus log KOW relationship was roughly linear over the log KOW range from 4.4 to 6.4 and displayed an increasing nonlinear deviation for log KOW values greater than 6.4. These relationships are qualitatively similar to those established for other aquatic organisms where bioconcentration from water was the mechanism involved. This suggests that interstitial water may be the phase from which lipophilic compounds in sediment are bioconcentrated by oligochaetes. An expression relating the bioconcentration factor to the biotic concentration and various sediment characteristics has also been developed.

Nutrient distributions and transport in Long Island Sound

Abstract Inorganic nitrogenous nutrient (NH 3 , NO 2 , NO 3 ) distributions and transport in Long Island Sound are investigated for both winter and summer conditions with a steady state, one dimensional mass balance model. Nutrient budgets based on horizontal exchange, lateral input from sewage and agricultural sources, and first order biochemical uptake (utilization minus regeneration) are computed for each of 13 regions in the Sound. All nutrient concentrations, principally ammonia, peak sharply in the upper East River where a strong point source exists. Concentration distributions and uptake rates are consistent with previous studies of the nitrogen cycle and productivity of the Sound. However, this paper stresses horizontal exchange and sewage as important and hitherto neglected components of the nutrient budgets in various regions. Estimates of the loss of nitrogen to the sediment are presented for the western, central and eastern regions, from the Sound to the ocean at the eastern end, and into New York Harbor from the upper East River. Sewage effluents are shown to be the prime external source of nutrients for the Sound.

Cost estimates for flood resilience and protection strategies in New York City

In the aftermaths of Hurricanes Irene, in 2011, and Sandy, in 2012, New York City has come to recognize the critical need to better prepare for future storm surges and to anticipate future trends, such as climate change and socio‐economic developments. The research presented in this report assesses the costs of six different flood management strategies to anticipate long‐term challenges the City will face. The proposed strategies vary from increasing resilience by upgrading building codes and introducing small scale protection measures, to creating green infrastructure as buffer zones and large protective engineering works such as storm surge barriers. The initial investment costs of alternative strategies vary between

Chapter 3: climate observations and projections.

11.6 and

Spreading and Mixing of the Hudson River Effluent into the News York Bight

23.8 bn, maximally. We show that a hybrid solution, combining protection of critical infrastructure and resilience measures that can be upgraded over time, is less expensive. However, with increasing risk in the future, storm surge barriers may become cost‐effective, as they can provide protection to the largest areas in both New York and New Jersey.

Numerical studies of small island wakes in the ocean

Climate change is extremely likely (see Fig. 3.1 for definitions of uncertainty terms and Box 3.1 for additional definitions) to bring warmer temperatures to New York City and the surrounding region (see CRI, Appendix A, for further information on all the material presented in this chapter). Heat waves are very likely to become more frequent, intense, and longer in duration. Total annual precipitation will more likely than not increase, and brief, intense rainstorms are also likely to increase, with concomitant flooding. Toward the end of the 21st century, it is more likely than not that droughts will become more severe. Additionally, rising sea levels are extremely likely, and are very likely to lead to more frequent and damaging flooding related to coastal storm events in the future. The treatment of likelihood related to the New York City Panel on Climate Change (NPCC) climate change projections is similar to that developed by the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4, 2007), with six likelihood categories. The assignment of climate hazards to these categories is based on global climate simulations, published literature, and expert judgment.

Coastal ocean circulation near Barbados, West Indies, spring 1990 and 1991

Abstract Results are presented from three Hudson River plume sampling cruises made in the New York Bight, in August 1976. The data show that the set and shape of the spreading effluent vary widely over time periods ∼6 days, and are clearly influenced by local wind stress. Application of Takanos model of a steady state plume spreading into a stagnant ocean suggests a horizontal eddy viscosity ~10 8 cm 2 sec −1 , and a strong anticyclonic deflection of the plume. This value is considered to be an overestimate, since interfacial shear stress is neglected in the model. More careful measurements and calculations are needed to separate out the effects of horizontal and vertical viscosities, Coriolis force, advection by a prevailing coastal current and local wind stress, on plume dynamics.