Studying Ocean Currents By: Carolyn Mondesi, Karlos Ramos, Phillip Abreu

Lagrangian method (Float method) Essentially means you study the current by tracking and drifting. The Lagrangian method involves floating something. An example of this is the research vessel Ben Franklin, which with a special submarine, studied the Gulf stream by floating in it for weeks with crew on board.

Eulerian Method (Flow method) In this method you study the current by staying in one place and measuring the velocity of the water as it flows by.

The Flotsam Method This method is used to study the distribution of chemical tracers, such as certain radioactive elements and fluorocarbons. If scientist know when and where the tracer entered the water, they can analyze for its presence to determine flow patterns and velocities. This is the basis for studying North Atlantic Deep Water and its connection to the ocean conveyor belt.

Instruments (Lagrangian) The langrian method takes very little to do you can simply toss something that can float into the ocean, However most oceanographers use a device called a drogue. A Drogue’s advantage is its ability to be pushed on by current not wind.

Continued... Scientist now use floats that transmit to satellites. The Argo float drifts at depths from 1500 to 2000 meters. It sends periodically the information like salinity, speed, direction, and temperature.

Doppler Acoustic Current Meter This instrument determines current direction and speed by measuring sound bouncing off particles suspended in the water and analyzing the echo frequencies. It's name comes from the Doppler shift which is the change in frequency due to speed or direction change.

Chemical Tracers One method to not use current instruments is using chemical tracer. Chemical Tracers like radioactive elements and fluorocarbons are measured by scientists the moment they enter the water, they can then analyze its presence to determine flow patterns and velocities. This is used in order to study the connection between North Atlantic Deep water and the ocean conveyor belt.

The Rubber Ducks Method In 1992 a ship sailing from China to Seattle lost 29,000 rubber ducks, frogs, and turtles. The toys washed up along the North Pacific coast at various locations from Oregon to Alaska, moving at a rate predicted by the improved current model. Scientist expect them to eventually wash up in New England. Almost anything that falls into the water and floats can give scientists insight into the behavior of surface ocean currents.

Multiple Choice Questions (Quiz) The __________ method studies currents by traveling with their flow. The __________ method studies currents by measuring the water that flows by a fixed point. Eulerian, Lagrangian c. Drogue, Lagrangian Eulerian, Doppler d. Lagrangian, Eulerian Examples of instruments or methods used to study currents include (choose all that apply) Drogues e. Satellites Argo float f. Radioactive Chemicals Flow meters g. Rubber ducks Doppler Acoustic Current Meters

Which method doesn’t require an instrument? Doppler Acoustic Current Meters e. Chemical Tracing Lagrangian Method f. Flow Method Eulerian Method g. Ben Franklin Method Flotsam Method h. Argo Float Method

Bibliography Current Publishing Corp. “Chapter 9 - Highways in the Sea.” Life on an Ocean Planet, vol. 1, Current Publishing Corp., Rancho Santa Margarita, CA, 2006, pp. 9–1-9–41. Novak, Skip. “Parachute Anchors.” 16 Sept. 2014. Abrish shewa, Student at addis ababa institute of technology Follow. “Chapter Four Fluid Mechanics.” LinkedIn SlideShare, 25 May 2015, Accessed 31 Mar. 2017. Robohub,robohub.org/3600-strong-underwater-robot-sensor-network-returns-1000000th- measurement-has-scientists-craving-for-more/. Accessed 31 Mar. 2017. www.argo.ucsd.edu/float_csection.gif. toxics.usgs.gov/photo_gallery/photos/capecod/CapeCodTracerTestDiagram_l.png.