Making observations at sea

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I've been an EML'er for exactly a year now, starting with my meager beginnings as an intern last May. This past year has been a fast pace transition. After graduating from the University of Maine in May of 2013 with a bachelor's in marine science, I essentially began working towards a master's in oceanography a week later. From that point on, I quickly evolved into a climate modeler and statistics geek. Now that the academic year is over, I can reflect back on my experiences as a first year graduate student and look forward to what the future may hold.

One such experience occurred during a recent (May 1-12) research cruise aboard the R/V Knorr. This cruise sailed between Woods Hole and Bermuda following a direct, linear path called Line W. The Line W field program is a long-term climate observing system put in place by the Woods Hole Oceanographic Institution (WHOI) in 2003. It consists of a moored array of 6 buoys extending over the shelf break. The goal of the program is to gather hydrographic data to better understand the baseline conditions of the Deep Western Boundary Current and Gulf Stream.

Line W is named after the late physical oceanographer, Valentine Worthington, who devoted much of his life and career to understanding the circulation and water mass formation in the North Atlantic Ocean. Like most great things in science, the Line W program recently came to an end due to unobtainable funds. I was fortunate enough to have been a part of its legacy by participating on the final leg of the program.
Scannell1.JPG On this cruise, we took shipboard hydrography measurements at 26 stations along Line W. We lowered a CTD rosette to depths beyond 5,000 meters to measure temperature, salinity and oxygen. An upward and downward facing acoustic Doppler current profiler (ADCP) was attached to the CTD to measure the water current velocity. From the CTD control station within the main lab aboard the Knorr, we fired Niskin bottles at different depths to collect 10-liters of water. A trip down to 5,000 meters can take over 3 hours, so a lot of time was spent waiting in the lab. The CTD and ADCP measurements allowed us to obtain vertical profiles of the Deep Western Boundary Current and Gulf Stream along the location where they intersect Line W. Changes in the global thermohaline circulation are expected to occur due to climate changes at high latitudes, and the past successes of the Line W program have given scientists the ability to document these changes through observational studies.

Yes, observations! During my experience on the Line W cruise, I couldn't help but fixate on the apparent divide between climate modeling and observational oceanography. Models enable us to force a condition, test our theories and make predictions, but perhaps every modeler should connect their virtual reality with hydrographic observations at sea. For me, this is exactly what Line W did.


As I look forward to the future, I am reassured as a modeler that the oceans continue to be explored, measured and observed through long-term field programs like Line W. 

On the Line W cruise, I not only gained a greater appreciation for the data I often take for granted, but I also gained a new admiration for the labor intensive field of observational oceanography.


Hillary Scannell, UMaine/GMRI

Photos provided by WHOI.

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This page contains a single entry by Hillary Scannell published on May 19, 2014 11:48 PM.

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