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Dispatch 12: Direct Observation

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September 17th Photos
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David Jones and Andrey Proshutinsky

September 17, 2017


Weather: fog light snow, 5-8 knot winds, ice covered seas

Temperature: -11 ˚C

Relative humidity: 91%

Location: Beaufort Sea, 80˚ 02’ N; 149˚ 40’ W

News

Overnight we made our way south and west stopping along the way for a couple of overnight XCTD casts and arriving at station CB11b for the final ITP deployment. Since the ice has thinned considerably it was decided to deploy the ITP and its buoy into open water rather than onto the ice since it will probably just fall through the ice anyway. Turns out the water deployed ITP's do pretty well in the open water because the ice will form around them incorporating them into a new ice floe. The deck deployment of an ITP is similar to the ice in many respects with the sequence of events being pretty much the same. Rather than using a tripod to lower the 280 pounds of anchor weights, cable, ITP, and buoy, the ship’s forward deck cranes were used to pull off the job. Once the ITP deployment was completed, we began to head directly south to stations CB11, CB10, and eventually CB9 which is also our first mooring station referred to as BGOS-B or simply Mooring Station B.

One could and should ask the question, is all the money, time, and energy being put into this research cruise and others like it really worth it? Given that we have instant access to unlimited information from Google, Google Earth etc, are the limited resources best utilized in this manner? I believe the answer can be stated in two words: direct observation. All science is based on asking questions and using experimentation and data to come up with the best explanation we can. Models of systems like the Arctic Ocean or the Beaufort Sea can be generated with our incredibly powerful computers, but the data sets for those models needs to be collected through direct observation. Once we have a model we need to know if it actually works so again we rely on direct observation. A good example of that is the Sponge Bobbers that were deployed earlier in the cruise. Their ever-changing positions can be determined through a GPS signal. But we had to get them out there in the first place. That is direct observation. Some preliminary data from the Sponge Bobbers that were recently deployed can be viewed in the photo gallery – image 12.

The red line and the blue line represent the Sponge Bobbers that were deployed along a shelf break. The green trace is a set of Sponge Bobbers deployed mid shelf. Shelf breaks are known to have faster currents and mid shelf currents are relatively weak and meandering. The movement of the different sets of Sponge Bobbers tends to confirm this. But tracking these 3 sets of Sponge Bobbers will no doubt give us an idea of how the currents of the Beaufort Sea interact with the shelf break currents and mid shelf currents; something that is not well understood.

Chemistry Timeout

Last edition we said that the more acidic a solution, the lower the pH number and the higher the concentration (mol/L) of the H3O+. Since the pH scale is based on powers of ten each move from one pH number to the next represents a ten-fold change in the concentration of H3O+. BUT, the twist is that a one unit decrease in pH is a 10 fold increase in H3O+. So pH 0 is 10^0 or 1 mol/L H3O+ concentration. A pH 1 solution is 10^-1 or .1 mol/L which is 1/10 the concentration of the pH 0 solution. When we keep going with this, a pH 2 solution has a H3O+ concentration of 10^-2 mol/L or .01 mol/L and is 1/100 the concentration of the pH 0. So this keeps going. A pH 7 solution (sometimes called the neutral pH) has an H3O+ concentration of 10^-7 mol/L or .0000001 mol/L and is 1/10000000 the concentration of a pH 0 solution. Finally if we go to a pH 14 solution, the numbers just keep getting smaller. The H3O+ of a pH 14 solution is 10^-14 mol/L or .00000000000001 mol/L, really small. So to simplify all of this and get rid of all those 0's we chemists use the 0, 1, 2....to represent those various concentration levels. The rule is as the numbers go up, the concentration of H3O+ goes down each by a factor of ten. Next time we'll bring CO2 back into the picture.

Crew Member Focus

Although not officially a member of the Coast Guard, Jean Pierre Desormier is the Medical Officer for the CCGS Louis S. St. Laurent. Officially he works as a nurse for Health Canada. Normally the Louis does not have a Medical Officer on board, but when she takes excursions into the far north, where medical care could be days away, she is required to have a Medical Officer aboard and that is when Jean Pierre comes onboard. So essentially the way it works is Jean Pierre works for Health Canada but then contracts with the Coast Guard via Oceans and Fisheries Canada (DFO) for six-week stints in the Arctic.

Jean Pierre lives in Drummondville, Quebec with his spouse and two of his three daughters. He comes from a family of nurses and has worked for Health Canada for 22 years, mostly in small native communities. In that position, where he is the only medical resource, he essentially does the job of a nurse practitioner. In those villages he has seen and dealt with anything and everything medical. It is that experience that makes him well qualified to work aboard the Louis.

This cruise is Jean Pierre's sixth cruise, all of which are six weeks long. In his role as the Medical Officer he is on call 24 hours a day, 7 days a week for any and all medical issues or emergencies. As a bonus he gets to wear the White Officers Shirt on Sundays along with all the other officers aboard.

Some Beaufort Gyre Science: Fresh water hydrological cycle.

The fresh water plays an important role in climate stabilization. It evaporates in the tropics and as clouds protects the ocean from overheating. In polar regions, it freezes and as sea ice, protects the oceans from overcooling.

Driven by atmospheric circulation, the fresh water moves from the tropics northward and precipitates over land (Greenland, Northern Canada and Siberia), and over the Arctic Ocean as rain and snow.

Rivers bring this fresh water from land to the ocean too, and then this water is transported back to the tropics by ocean currents to close this very simplified hydrological cycle schematics (see schematics in Photo 12-12).

In some regions, Greenland for instance, the fresh water can be accumulated and stored as ice. In this case, the hydrological cycle cannot be closed (this water does not return to the tropics) and ocean water in the tropics becomes too warm and salty. During periods of a cold climate, there is a deficit of fresh water in the ocean and the sea level stays lower than normal. In warm climate conditions, the land ice melts and water returns to the ocean; ocean level rises and climate cools down. Periods of climate variability associated with Greenland fresh water accumulation and release range from tens of thousands to hundreds of thousands of years.

The climate variability with shorter periods of variability (10 to 15 years) are called decadal. They can be regulated by fresh water accumulation and released in the oceans. For the Arctic climate changes at decadal scales, the Beaufort Gyre fresh water reservoir plays this role. Some hypothetical mechanisms of decadal climate variability for the Arctic will be discussed in tomorrows dispatch.



Last updated: September 18, 2017
 


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