A two-dimensional response to a tropical storm on the Gulf of Mexico shelf

Surface current data from drifting buoys and remotely sensed wind data recorded over the continental shelf in the northeastern Gulf of Mexico during the passage of tropical storm Josephine in October 1996 are examined. Drifter data show the existence of a strong surface jet (velocities reaching 1 m s⁻¹) that moves up the west Florida shelf and westward along the Louisiana–Texas shelf, and lasts for nearly 1 week. The coastal jet occurs during an intense synoptic scale wind event where wind speeds reach 15 m s⁻¹. A simple force balance and statistical analysis are performed to assess the role of strong wind forcing. The primary balance shows an Ekman-type current. The role of local acceleration is greatest when winds are directed along bathymetry. A simple two-dimensional strongly forced shelf response model developed from the linear steady-state momentum equations also indicates larger along-shore currents due to both Ekman-type forcing by cross-shore winds and a cross-shore pressure gradient arising from conservation of mass. Model parameters fit empirically are within 15% of theoretical values. The simple model explains 30% and 46% of the variance in the observed along-shore and cross-shore surface currents, respectively.     

Numerical experiments on the prediction of sea surface temperature anomalies in the Gulf of Mexico

The conservation of thermal energy equation applied to the mixed layer of the ocean, has been used to predict the sea surface temperature anomalies (SSTA) and the month-to-month changes in the Gulf of Mexico. The model includes the horizontal transport of heat by mean ocean currents and by turbulent eddies, as well as the heating by short and long wave radiation, evaporation and sensible heat given off to the atmosphere. A comparative study is carried out on the relative importance of the heating and transport terms. An objective verification of the skill of the predictions is presented for each season and for the whole period from March 1986 to February 1987. The predictions using only the heating terms have some skill over the control predictions (persistence and return to normal). The skill is substantially increased when the horizontal transport of heat by turbulent mixing is included in the model. The incorporation in the model of the Ekman wind drift current anomalies computed from the anomalous surface geostrophic wind improves appreciably the skill of the predictions in winter and fall.The mixed layer depth computed using the Kraus and Turner theory with dissipation, shows that the depths in summer and fall are shallower than in spring and winter. The effect of the shallow mixed layer depth in the model becomes apparent in summer and fall, improving the skill of the predictions in these seasons, with respect to the skill obtained using a constant mixed layer depth of 60 m.The incorporation in the model of the cooling in the mixed layer by turbulent entrainment of colder water from the thermocline, does not improve in an appreciable way the average skill of the predictions.     

Nutrient biogeochemical cycles in the Gulf of Riga: scaling up field studies with a mathematical model

A box model has been implemented to understand the large-scale biogeochemical cycles of nitrogen, phosphorus, and silicon in the Gulf of Riga. The large data sets collected within the international Gulf of Riga Project in 1993/1995 were used to validate the model. The comparison to data was useful in scaling up to the gulf-wide level and scrutinizing the conclusions based on short-term field surveys and experimental studies. The simulations indicate that the limiting role was passing from silicon to phosphorus to nitrogen over the seasons of organic production. However, on an annual scale, nutrient limitation was close to the “Redfield equilibrium”. Mass balance considerations, based on modeled coupled fluxes, disagree with the conclusions on low sediment denitrification and high phosphorus retention in the pelagic system, which were derived from isolated measurements.Nutrient budgets constructed with the model revealed the high buffer capacity of the Gulf of Riga. The nutrient residence times span a range from 6 years for N to 70 years for Si. The buffering arises from intensive internal recycling in the water body and by the bottom sediments. The budgets indicate that the Gulf retains about two-thirds of external nitrogen and silicon inputs, while phosphorus retention is only 10%.A slow response to external perturbations is demonstrated with numerical experiments run for 15 years under 50% reductions of terrestrial nutrient inputs. These experiments imply that the most effective is the N+P reduction scenario, which resulted in a 20% decrease of primary production after 12 years. A reduction of P resulted in only a 6% decrease of primary production; however, it yielded an 80% drop in the amount of nitrogen fixation.     

A Practice-Based Coupling of the Precautionary Principle to the Large Marine Ecosystem Fisheries Management Concept with a Policy Orientation: The Northeast United States Continental Shelf as a Case Example

This article addresses interdisciplinary sustainable aspects of fisheries as part of ocean management. Human-caused impacts and their role as modifiers of living marine resources is discussed. The research note also theorizes about contemporary global change and its prospective biological consequences, especially when coupled with human-induced factors in coastal marine waters. Also addressed is the management and ecological aspects of fish stock populations as part of a large marine ecosystem (LME) in the Northeast United States continental shelf of the Atlantic Ocean with suggestions for an interdisciplinary policy orientation paradigm to foster the sustainability of marine life in the sea.     

Characterization of fall–winter upwelling recurrence along the Galician western coast (NW Spain) from 2000 to 2005: Dependence on atmospheric forcing

Upwelling events driving ENACW (Eastern North Atlantic Coastal Water) into the Galician western coast rias had been considered typical spring–summer processes, according to the research developed in this area. However, they can also be observed in fall or winter under northerly winds blowing at shelf. Six different upwelling events were analyzed in the Ria of Pontevedra during the wet season (NDJF) from 2000 to 2005. These events were characterized by means of the zonal Ekman transport (Q_x) at four control points in front of the western rias (locally known as Rias Baixas) and thermohaline variables measured at a fixed station in the main mouth of the Ria of Pontevedra. The duration of the upwelling events ranged from 27 days (during February and March 2002) to 69 days (during November–December 2004 and January 2005). Upwelling events studied in the Ria of Pontevedra from 2000 to 2005 showed the similarity in upwelling features during both seasons (similar wind forcing and upwelled water). Finally, Q_x was correlated with the most representative atmospheric patterns in the Northern Hemisphere (EA, NAO, EA/WR, POL and SCA) from 1966 to 2005. The winter EA pattern has the most influence on Q_x showing an annual evolution with a prevalence of the positive phase from 1976 on. This positive phase is directly correlated with a prevalence of positive values of Q_x which are upwelling unfavorable in the Rias Baixas.     

The study on maritime transport along the southern coast of Thailand on the Gulf of Thailand: a summary

This paper examines the potential of developing coastal ports and channels along the Southern coast on the Gulf of Thailand. There were 18 channels included in the study area, ranging from Ban Don Channel to Pattani Channel. The study approach was based on the analysis of the data on cargo movement to and from the study area by coastal shipping and truck, in terms of quantity and types of cargo. The study found that there are three potential areas to be developed for coastal shipping in Thailand (along the southern part on the Gulf of Thailand), namely Songkhla (Songkhla channel), Surat Thani (Ban Don and/or Ta Thong) and Nakhon Sri Thammarat (Sichon and/or Pak Phanang). This paper, however, suggests that further study on the technical part for support of the precise channels to be developed is needed.     

The study on maritime transport along the southern coast of Thailand on the Gulf of Thailand: a summary

This paper examines the potential of developing coastal ports and channels along the Southern coast on the Gulf of Thailand. There were 18 channels included in the study area, ranging from Ban Don Channel to Pattani Channel. The study approach was based on the analysis of the data on cargo movement to and from the study area by coastal shipping and truck, in terms of quantity and types of cargo. The study found that there are three potential areas to be developed for coastal shipping in Thailand (along the southern part on the Gulf of Thailand), namely Songkhla (Songkhla channel), Surat Thani (Ban Don and/or Ta Thong) and Nakhon Sri Thammarat (Sichon and/or Pak Phanang). This paper, however, suggests that further study on the technical part for support of the precise channels to be developed is needed.     

海岸工程设计波要素推算方法探讨——以如东人工岛设计波要素推算为例

以如东人工岛设计波要素推算为例,分别利用历史台风天气图推算法和设计风速推算法推求不同重现期设计波要素并进行对比分析。结果表明,两种方法各有优劣,但历史台风天气图推算法的计算精度比设计风速推算法的精度差,为了安全起见,建议采用设计风速推算法。     

保险人基于损害补偿原则的拒赔抗辩——在《沿海、内河船舶保险条款》下的讨论

以沿海、内河船舶保险中保险人的视角,寻求其在《沿海、内河船舶保险条款》下以损害补偿原则作为拒绝赔付被保险人的抗辩理由的法律正当性,并试图通过探究这些原则和条款本身的内在涵义,为保险人和被保险人双方提供实践的参考;同时在分析这些抗辩理由在司法实践中的现实价值的过程中,进一步揭示该领域相关问题的法的实然所在。