Introduction The questions what causes polar ice to melt, variation in temperature at same latitudes, climate change and others have led meteorologist, ocean scientist and other researchers to investigate currents. According to the oxforddictionaries.com, a current is a body of water or air moving in a definite direction, especially through a surrounding body of water or air in which there is less movement. Currents can be generated both on the ocean surface flowing horizontally and sub surface flowing vertically. However these currents are generated by different factors. Horizontal currents are generated by the wind blowing across the ocean surface while vertical currents are generated by the density differences in water masses caused by temperature and salinity variation. To understand the significance of these currents researchers used a number of oceanographic tools which incorporates different techniques to measure them. The Lagrangian measurement incorporates all drifter measurements, which was named after the mathematician Joseph Louis Lagrange while the Eulerian measurement incorporates measuring currents of a fluid at only a given point and was named after Swiss mathematician Leonhard Euler (oceanservice.noaa.gov). Ocean currents are typically measured in Knots. According to NOAA ocean service education, Knot is defined as one nautical mile per hour and is used to measure speed (oceanservice.noaa.gov). Oceanographic Tools to Measure Currents Incorporating both the Lagrangian and Eulerian measurements allowed researchers to measure both surface and sub surface currents. The floating devices, which scientist call a ‘drifter’, to take the measure surface current as well as devices which scientist call a ‘profiling floats’ ,... ... middle of paper ... ...er fisher come and feed on the smaller fisher and hence produces a large fishing industry. When two currents flow towards each other on show it pushes the flow of the current outward which causes a rip current. Rip current can be dangerous but it is an easy way for surfers to get out in the sea and catch the wave. Works Cited current: definition of current in Oxford dictionary (American English) (US). (n.d.). Retrieved from http://www.oxforddictionaries.com/us/definition/american_english/current NOAA's National Ocean Service Education: Currents: How Are Currents Measured?(n.d.). Retrieved from http://oceanservice.noaa.gov/education/kits/currents/07measure2.html NOAA Ocean Explorer: Education - Multimedia Discovery Missions | Lesson 8 - Ocean Currents. (n.d.). Retrieved from http://oceanexplorer.noaa.gov/edu/learning/8_ocean_currents/ocean_currents.html#slide
walking across them. The lines and pulleys and some parts of the waves are example of
Figure 6 - How longshore drift works (Brief). Source: Classwork image (originally from Google images)
Rachel begins by stating that when tides or waves occur in the ocean they don’t just effect the surface but also the deepest levels of the water. How would you know for a fact that the wave currents run deeper than just the surface? Proof given by her illustrates
The vertical flow velocities show that the flow is attempting to push the wake in, from both the top and bottom of the wake, and restore the water to its original state of steady flow.
“The world’s smallest porpoise is slipping closer to extinction…” (Malkin). This porpoise is called a vaquita, and they are being run into extinction because of drift nets set for their larger cousin, called the totoaba. But, this isn’t just happening with these species, it is happening to many species all over the world. A drift net is a large net that is placed underwater for catching fish. Taking all of these fish out of the world’s oceans does not have a positive impact on the ecosystem. Michael Pollan, author of The Omnivore’s Dilemma, talked about destroying the ecosystem through farming (162), but he didn’t mention how it can also happen through fishing Fishermen should stop using drift nets to collect fish because they can catch the
That complexity makes it difficult to measure. Nearly all of these channels funnel into Baffin Bay. The Davis Strait bounds the southern end of Baffin Bay, and thus provides a convenient “choke point.” By measuring at this one location (rather than in the many channels to the north), it captures all of the water going in and out of the Canadian Arctic Archipelago. As a connector between the Arctic Ocean and the Atlantic Ocean, the Davis Strait is a unique environment to study water
In order to explore the tides one must first deduce the big ideas needed to understand them. These include factors that can affect the tides such as the geography of an area and gravitational pulls. Also a separate look at solar and lunar tides will be taken. Finally tidal predictions will be taken under consideration...
Salmon Fishery Management in Alaska. (n.d.b). NOAA Fisheries Alaska. Retrieved February 18, 2011, from http://www.alaskafisheries.noaa.gov/sustainablefisheries/salmon/default.htm
Surf experts say rips are a danger to beachgoers, whether they are experienced or not. Rips are strong, powerful currents of channeled water that flow away from the shore and pull swimmers out to sea. They are complex and can quickly change shape and location, and are at times difficult to sea.
Ocean currents are horizontal or vertical movement of both surface and deep water throughout the world’s oceans (Briney, n.d.). The primary generating forces are wind and differences in water density caused by variations in temperature and salinity. Currents generated by these forces are modified by factors such as the depth of the water, ocean floor topography and deflection by the rotation of the Earth. Horizontal currents are wind driven, fast moving and carries small amount of water; while, vertical currents are slow moving, density driven and carries large bodies of water. In this paper I will describe horizontal and vertical currents, their importance and some of the tools used to measure ocean currents.
Multiple satellite methods exist for remote sensing of rip currents each with their own benefits and drawbacks. Photobathymetry, currents interaction using with Synthetic Aperture Radars (SARs), wave refraction, and wave kinematics bathymetry (WKB) are current technologies that are used most often due to the current satellite knowledge. Each of these techniques can be applied using low orbit satellites that are already currently orbiting Earth. All techniques aside from WKB have been tested as satellites for several years. WKB has been operational for 20 years, but not from a satellite until recently (1). Each method has a unique background as well as functionality that make them suitable for various constraints.
The currents at the surface of the ocean are split in to two categories, tidal currents and surface currents. Tidal currents occur around land masses and are influenced mainly by the gravitational pull of our sun and moon. They change rapidly but predictably and contribute to surface currents. Surface currents occur over different areas of earth’s ocean. Two main factors affecting the surface currents are wind and the Coriolis Effect. The Coriolis Effect explains how the rotation of the earth seems to cause a deflection of anything moving above the earth’s surface. It is this effect that causes winds and water in the northern hemisphere to appear to deflect to the right and in the southern hemisphere to deflect to the left. One of the major surface currents is the Gulf Stream. Water in around the Caribbean is warmed by the sun and then carried north and east along the coast North America. These sun warmed waters release their stored energy into the westerly winds and Northern Europe benefits by having a much milder winter than t...
Bathymetry is a study of underwater depth which can map large or small scale bodies of water. It is one way to measure, manage and explore water bodies. Earliest bathymetric systems used premeasured anchors or ropes to measure the depth of water on a single point of time. Bathymetry, until now has been used for a wide range of applications such as feature extraction, coastal mapping, road map guide for sea navigators, monitor erosions, monitor water rise, and classify the behavior of the community under water. For more than 50 years of development, bathymetry is done with the help of acoustic technology, namely Sound Navigation and Ranging (SoNAR). Using the basic principle of Physics, a transducer emits high frequency sound to the body of water.
“Tide Predicting Machines.” NOAA Tides & Currents. NOAA, 15 Oct. 2013. Web. 14 Apr. 2014.
The main idea behind El Nino is that the wind changes direction across the Pacific Ocean. In a non El Nino year (normal), the trade winds blow from east to west across the ocean, from North and South America towards the tropical regions of the Pacific Ocean. In an El Nino year, the trade winds change direction and blow from Asia and the tropical Pacific towards North and South America (NOAA B, 2004). The changes in these winds, commonly called Southern Oscillation winds because the majority of activity happens in the southern parts of the Pacific, produce many other changes. In the final analysis, the winds are the root of this scheme. John Daly (2004) discussed how the winds produce major changes in the temperature of the ocean water. This is the second main concept of El Nino. In normal years, when the wind blows from east to west, the temperature at “Sea Surface” is about 8 degrees cooler in the west than in the east. During El Nino, the winds blow a certain amount of water towards the west, thus piling it up and making its depth approximately one half meter deeper. Because of the loss of water at either coast, the deeper ocean water rises to replace what is gone. The deeper/cooler water is the source of many incomes in North and South America; however, in an El Nino year, the warmer water sits on top of the ocean, which creates many tribulations relating to both income and weather. The last main point of El Nino is the weather that follows due to the changes in water temperature. Precipitation follows the warmer water, whichever direction it flows. During the normal wind patterns the rainfall in the southern Pacific islands is consistent and creates their tropical identity. Whe...