Winds and currents

A special device was used to collect artificially resuspended sediment. In this device, the sediment was placed in a tube with overlying water. An oscillating grid placed in the water above the sediment caused a steady state resuspension equilibrium, under the same conditions as typically generated by winds and currents in the lagoon. This overlying water was then filtered, and the resuspended material analysed. 

Density stratification in coastal waters can result from increased freshwater flows from land due to heavy rainfall, and from seasonal surfece warming. Changes in winds and currents alter upwelling conditions that can also affect stratification, while concurrently affecting nutrient resupply to the surface waters. These changing environmental... 

Yirioplankton viruses that live in the water column and are vulnerable to the movement caused by wind and currents. 

Polynesians combined what they knew about the weather, winds, and currents to investigate the Pacific Ocean, while the Phoenicians, Greeks, and Arabs explored the Mediterranean Sea. The early Greeks in general and Herodotus (484-428 B.c.) in particular believed that the world was round. Heroditus performed studies of the Mediterranean, which helped sailors of his time. He was able to take depth measurements of the sea floor by using the fathom as a unit of measure, which was the length of a man s outstretched arms. Today the fathom has been standardized to measure 6 ft (1.8 m) in length. 

Effect of different wind and current directions on the movement of an oil slick... 

Winds and currents also spread the oil out and speed up the process. Oil slicks will elongate in the direction of the wind and currents, and as spreading progresses, take on many shapes depending on the driving forces. Oil sheens often precede heavier or thicker oil concentrations. If the winds are high (more than 20 km/h), the sheen may separate from thicker slicks and move downwind. 

When attempting to determine the movement of an oil slick, two factors affect accuracy. The more significant factor is the inability to obtain accurate wind and current speeds at the time of a spill. The other, very minor factor is a phenomenon... 

Spill models operate in a variety of modes. The most typical is the trajectory mode that predicts the trajectory and weathering of the oil. The stochastic mode uses available data to predict a variety of scenarios for the oil spill, which includes the direction, fate, and property changes in the oil slick. In another mode, often called the receptor mode, a site on the shore or water is chosen and the trajectory from the source of the oil is calculated. Increasingly, statistically generated estimates are added to oil spill models to compensate for the lack of accurate knowledge of winds and currents. 

The potential negative feedbacks tend to stabilize atmospheric C02 and 02 concentrations in the long term. However, the processes represented by boxes in Fig. 6.5 are the result of tectonic activity and so are not controlled by feedbacks. They have the potential to disrupt the carbon cycle severely, as considered in Section 6.3. As indicated in Fig. 6.5, oceanic circulation can influence the C cycle in complex ways via its influence on climate, through its impact on heat distribution over the surface of the Earth and the rate and net direction of C02 exchange with the atmosphere. Similarly, continental relief and distribution have an effect on the climate through their influence on winds and currents. All these factors are investigated in Section 6.3.1. 

Roether W, Mutmich KO, Ostlund HG (1970) Tritium profile at the North Pacific (1969) Geosecs Intercallibration Station. J Geophys Res 75 7672-7675 Roether W, Schlosser P, Kuntz R, Weiss W (1992) Transient-tracer studies of the thermohaline circulation of the Mediterranean. In Winds and Currents of the Mediterranean Basin Reports in Metereology and Oceanography 41, Vol. 2. H Chamock (ed) p 291-317... 

The safety of personnel transfers depends on many factors. The type of shore facility, the access site on the transfer vessel, the foundation and transition piece, and weather and sea conditions (waves, wind, and currents) influence whether safe access or egress is possible and the type of access system or vessel used. To minimize risk and maximize efficiency, any type of transfer vessel will need to nose into place easily and quickly rest safely in position at the transfer point and transfer personnel and equipment quickly, safely, and reliably. Above all, any personnel transfer system should maximize safety and minimize complexity. 

First of M. F. Maury s publications on winds and currents at sea is written. 

Equations (20.24) and (20.25) were developed for spills of constant volume, constant surface tension, and low viscosity on calm water. The effects of wind and currents on spreading rates are not well studied and are difficult to estimate. Therefore, the quantifiable uncertainty in the spreading rate lies in the estimation of the parameters used in Eqs. (20.24) and (20.25). The transition from a viscous spread, i.e., Eq. (20.25) to a surface tension spread, i.e., Eq. (20.23) occurs rapidly for most spills, and the spreading rate is described by Eq. (20.24). Since the density and viscosity of water can be estimated fairly confidently, most of the uncertainty in the spreading rate lies in the estimation of the net surface tension, specifically in the estimation of the air-oil surface tension and the oil-water surface tension. There is also an uncertainty in the applications of the slick-spreading model to a cross-sectional nonuniform velocity profile, where the nonuniformities would add to the spreading. In this case, the slick would experience a longitudinal dispersion in addition to the water. This phenomenon is not a component of the sensitivity analysis. 

Mean wind and current velocities are considered negligible during the passage. Their possible effects on the maneuvering conditions and ship response have been included as model uncertainties. The nominal value of the local depth along the channel was obtained from bathymetric data in LWL. The relative error in the depth measurements is 5%. The morphologic state during the storm event is considered stationary (i.e., Tc). The presence of small-scale bedforms and... 

Chapter 2 gives a thorough survey on data regarding the effect of ice floes. When floating ice sheets move under the influence of strong winds and currents, a seagoing vehicle or a semi-submersible will be subject to an impact given by... 

Inflatable booms use less storage space and can be deployed from ships or boats in open water. Towed booms Figure 3) are good for preventing dispersion of oil by winds and currents. 

Pollutants spread through the environment by convection (winds and currents) and by diffusion. How many steps must a molecule take to be 1000 step lengths away from its origin if it undergoes a one-dimensional random walk ... 

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