Modeling Ocean Acoustic Tomography
Ocean acoustic tomography is a recent scientific breakthrough in the last thirty years. This usage of this tomography is key because of the major affect the oceans play on the Earth’s biosphere. Water takes up about 75% of the world and plays a role in land temperature variance and seasonal climate changes.
In 1965, scientists pictured the ocean’s general circulation being large slow-moving currents like the Gulf Stream. These conclusions were based on periodic observations. No one had a grasp on the water’s vast expansion and high reaching depths.
In the 1950’s and 1960’s, new instruments were brought to the table. Subsurface floats moved with the ocean currents. Data was gathered while a signal was emitted so ships could track it. Ocean current meters weren’t mobile, but rather fixed to one location. They would remain anchored for several months gathering the changes within the water around them. These tools discovered variability within the water’s movements. The theories on slow, basin-scale currents were hidden by the domination of mesoscale fields. These fields are high energy flows that reach ten times the average velocity of major currents. These up-tempo movements relate to the out of water weather patterns. A mesoscale can be 100 square km in size and persist for 100 days while atmospheric weather will be 1000 km, but only resonant for 3-5 days. 99% of the ocean’s kinetic energy can be summed into these mesoscale rather than the slow basin-scales.
Monitoring the newly discovered mesoscales became a problem. A grid would have to be set up with monitoring equipment at 50 km intervals. Sensors would be lowered to average ocean depths (approximately 5...
... middle of paper ...
...phy system along with the old ship method. The tomography setup accomplished the task in 24 hours. It took the ship, though, three weeks because each interval stop took 4-5 hours. The map was also blurred because of the long “exposing” time. Quickness has become a major role characteristic, along with coverage. 1000 km of a current was measured for temperature averages. The methods are near the point of being able to measure temperatures around the world simultaneously for references on global warming. 75% of the world is water. Finally, we are being able to study it and apply it to weather patterns within the air.
Works Cited
Munk, Worcester, and Wunsch. Ocean Acoustic Tomography. New York: Cambridge University Press, 1995.
Spindel, Robert C., and Peter F. Worcester. “Ocean Acoustic Tomography.” Scientific American Oct. 1990, vol. 263: 94-99.
The next method that was discussed in the article was side-scan sonar systems. This method uses an object that is shaped like a torpedo; this is then towed behind the ship at a depth that is around 10 percent of the width. The side-scan method uses two fan shaped beams, as the beams reflect off of the sea floor there is a scan line that when plotted with the other scan lines an image is created. This method also has it’s downsides as well radiometric artifacts are harder to distinguish than geometric artifacts, this can lead to some artifacts not being noticed or being confused with natural objects such as rocks.
Ultrasounds use the same concepts that allow sonar on boats to see the bottom of the o...
Review: The opportunity and endeavor of exploring the Earth’s oceans can reap great rewards for mankind and unravel many of the mysteries that the Earth has left to discover.
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).
The Sun’s radiation heats the upper atmosphere, sending the energy toward the earth’s surface and finally mixes with the planet’s counter-rotational currents, creating jetstream flows. The winds flow over the ocean’s surface creating friction that spawns chops, pushing up the seas forming perfect bands of open ocean swell. Pushed on by gravitational forces, the swells speed away from the winds that they came from, moving across the deeps until they feel the drag of the shallows near the coast. As the swells rise up out of themselves, they peak, curling into the liquid dreams that we surfers ride (Kampton 4).
Sound waves are measured in frequency which can be defined as the number of pressure waves passing a fixed point in a set time. “The velocity of sound in seawater is approximately 1500ms”(Wright et al., 1995, p. 71) Wavelength is the distance
Nearly 500 whales beach themselves every year due to an excessive use of sonar. Military passive sonar (sound navigation and ranging) is killing and causing whales to avoid their major feeding and breeding grounds while temporarily deflecting from the high frequency sound coming from this unknown source. This event is raising hell in the political sector. Scientists have found many similarities between all the beached whales that have been in the same area that military sonar was being used. Military sonar is affecting the life of whales and their natural habitat for the worst.
What do the scientists plan to do to measure Ocean Acidification on this cruise? Scientists plan to measure ocean acidification on this cruise by equipping each mooring line with a ‘CTD’ that measures the water’s conductivity (salinity), temperature, and depth (pressure). In addition to measuring these tracers, each line is equipped with current meters (RCM-8 and ADCPs) that determine both themagnitude and direction of the water flow. Continuous measurements of current velocities, temperature and salinity supply the information needed to construct an annual budget for heat and salt transport through the Strait.
variety of means such as ship surveys, and remote sensing will lead to a better
I decided to focus this Mathematical Exploration on the math behind oceanic tides. I began by looking at the generic possibilities set out by my teacher. Among them was the idea of math being applied to water. In my initial search I found nothing that seemed interesting to me, however, I wanted to stick to the broad topic of water. After continued search I decided to focus on a subject important to me the ocean, specifically oceanic tides. Every year my family takes a trip to California for a week at the beach and since I was a little kid I was perplexed that the water would come up the beach at night and recede during the day. As I grew older and I learned this movement was called the tide and was caused by the moon and the sun’s gravity affecting the ocean. Thus I decided to take the exploration as a chance to further my knowledge of this subject and tides became my subject for this.
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.
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...
An acoustic wave can simply be described as a longitudinal wave. A longitudinal wave is a wave that vibrates and moves in the direction of its propagation. This means the medium is either in the same or opposite direction of the way the wave travels. Acoustic waves are a form of Mechanical longitudinal waves; these waves are otherwise known as compression waves or compressional waves. Compressional waves obviously produce compression, decompression, and rarefaction to travel.