One of my buoys beached! BUT WENT BACK OUT TO SEA!!!

Hey Everyone,

Today's post is a bit different, I will talk a tiny little bit about my research, but don't worry it should be fun or at least interesting.
I want to tell you about a buoy, a small buoy, that has had an interesting life and has recently beached on the Shetland Islands (Scotland).

Buoy 300234010730040 is a small iSphere drifting type buoy. These buoys, developed by MetOcean are designed to be deployed in open water and track the drift of the surface water. They are very much like the MetOcean SVP, or the MetOcean Polar iSVP but are more simple (maybe I should get paid some advertising money by MetOcean??). The buoys have a normal maximum life time of about 12-18 months, at least from our experience.  They are rated for longer, but often stop working, either crushed by the ice or ??

They are used in the sea ice community as an inexpensive drift buoy for tracking the motion of sea ice, we just place them on the ice instead of in water. The buoys provide measurements of their position via GPS. You can also request other sensors such as air temperature, sea surface temperature, barometric pressure, humidity and other sensors (see the website).

Now Buoy 300234010730040 is a simple model, just has temperature and position. We deployed this buoy in the Lincoln Sea of the Arctic Ocean during the ESA CryoVEx campaign in April 2011.  The Lincoln Sea is between Greenland and northern Ellesmere Island. It is the main study region of our group because the ice drifts towards the coasts in this region producing very thick sea ice that usually survives the summer to become multi-year ice.  The Lincoln Sea sits north of Nares Strait, where sea ice can flow out of the Arctic Ocean to the warmer waters to the south and then melt.

During the CryoVEx campaign we deployed four of these buoys. We had two main research sites called North and South at 85.5 and 83.5, respectively. At each site we put out two buoys to track the location of the sites between two visits we made and for aircraft surveys over the sites.  Above each buoy we placed a corner reflector.  A corner reflector is just a bit of metal that is shaped into a corner and then point so that the bottom of the corner is down. When radar signals from the aircraft hit the corner reflector they bounce right back to the sensor. Normally, when radar hits a surface, only some of the energy goes back to the sensor, the rest is mainly reflected away.

Buoy and Corner Reflector. Photo Courtesy of Rosemary Willatt, (C) 2011.

Okay, so we used the buoys successfully during the campaign, we took down our corner reflectors on the second visit the in-situ  team made and decided to leave the buoys to track the ice.


Okay, now the interesting bit, of the four buoys that we deployed, two are still working. One of the buoys from the north site died in October of 2011, so it definitely did not make the 18 month expected lifetime.
The second buoy from the north site is still operational, and amazingly is still in the Lincoln Sea.  It has spent more than two years there now, it is a pretty interesting data record.  In 2012, we looked for it from the air, but I think it was buried. I guess this because 1) they are bright orange and can be pretty easy to spot, and 2) the temperature profile from the buoy was very smooth in 2012, which may indicate it was buried in snow as the snow would limit fluctuations in temperature.

From the South site both buoys drifted out of the Lincoln Sea  through Nares Strait in October 2011. And then their lives get interesting.  Below is a map showing the positions from Buoy 30023401070040 (i.e. the buoy that is still going).

Both buoys drifted south into Nares Strait. Both had drifted quite aways south but then a strong wind from the south sent the ice drifting back up the strait but this time on the opposite side of the channel. Pretty cool.

After this they flowed south past Baffin Island and into Hudson Strait. The buoy that is still running drifted back out, while the other one beached on shore.

Here you can see that the buoy spent a bit of time circulating in and out of Hudson Strait/ Ungava Bay.

Since then the buoy has travelled all the way to Ireland, then most of the way back to Greenland and then now up to the Shetland Islands.

Buoy 300234010730040 travelled somewhere around 22,000km (I have not gone through all the gps points to remove outliers, but did remove a couple).  22,000km is longer than all of the coastline of the U.S.A. (according to the CIA World Fact Book (here), or a little less than 4 times the distance from Edmonton to Tromso, or (last one I promise) about 5 times the distance between Edmonton, AB and the North Pole.
Compare this to the buoy (300234010735050) that has stayed in the Lincoln Sea.  In two years, it has travelled only about 1700km! That's less than 10% of Buoy 300234010730040.

Here is the temperature record from the buoy. Some interesting things, the melt in 2011, then maybe sitting in water, maybe a melt pond, or open water, then back down to freezing temperatures and then finally warming.  Can see some points big changes in temperature in May and June 2012, but it was near Hudson Strait then.

If you look at all the buoys together, there are many cool features sitting in this data, for instance, Buoy S1 and S2 were together, separated by about 460m until September 5, 2011. Then the ice floes that each one was on started drifting apart, then smashing back together, then apart, and eventually one or both of the floes was/were turning and coming closer to the/each other.


OKAY!  BACK TO THE BUOY'S DRIFTING LIFE:

Last week, the buoy was beached on a small beach near Gunnister, Shetland Islands, Scotland.
It spent a couple days on the beach, and then with a high tide ?? and maybe some wind and good fortune, it drifted back out to sea.  Who knows maybe some one pushed it back out. In any event, it can continue on its' merry way.  Below are some Google Maps Street View pictures of as close to the spot the buoy beached as you can get.

In the picture below you can see the beach where the buoy beached. Nice place for a rest.

I had hoped it would go up the coast of Norway, but hey let's just see where time takes it.  It is currently heading back out into the Atlantic towards Greenland ( though still not far from the Shetlands). I'll try to remember to post about this buoy when it finally dies, as it inevitably will. For now, the battery voltage is high (very high actually), so who knows where it will end up and when it will die, hopefully not for awhile.