CryoVEx 2014: ONR/MIZ Camp 2

First thing each morning and at 1930 each evening we would call back to Sachs Harbour to let people know we were alive, to report weather and visual conditions, and to learn various plans for the day as it pertained to the different groups. 

With our successful day yesterday we were ready to move on to Camp 2 and were really hoping that the British Antarctic Survey (BAS) team was ready to move to Camp 3; our morning checkin confirmed this to us.

One of the only issues we had the day before was that our ground based electromagnetic induction sensor, the EM31 was not working.  This sensor measures the distance between itself and conductive layers underneath it, so we use it to measure the total snow plus ice thickness.  The sea ice is salty but relatively non-conductive, sea water though is very conductive and so it returns a signal to the sensor. It is a nice way to fill in the spaces between our manual drill hole measurements.

During our morning check in we asked for our backup EM31 to be flown to us. We had one sitting in its shipping box, and the empty shipping box from the one we took on the ice, guess which case we got?  The BAS Twin Otter showed up from Sachs Harbor first to drop off buoys for the BAS team while the Ken Borek Twin Otter went to Camp 2 to drop off the rest of our equipment and to pick up the BAS team.  The EM31 case on the BAS Twin Otter was the empty shipping case.  We made a few phone calls and quickly had the right box thrown onto the Ken Borek Twin Otter to be brought to Camp 3 for a quick survey.

Arrival of BAS team from Camp 2. 

Above you can see us eagerly greeting the Ken Borek Twin Otter, hoping that the EM31 was on it, and it was.  The plan we developed was to slowly offload the BAS team and then slowly load up our stuff so that Christian and Bruce would have time to quickly use the EM31 on our survey lines.  The first problem was that our EM31 was at the bottom of the gear pile from BAS, and the second problem was that everyone was WAY TOO HELPFUL and was putting gear on the plane very quickly (not something I would normally worry about).  In the end it did not matter anyways, we asked the pilot for some extra time to survey the line but as luck would have it, this EM31 did not work either!! The first unit had been for maintenance and calibration just before the survey and the second unit was a rental! What was going on?! We had no choice but to pack up and move on to Camp 2. It was another cold windy day, you could see frost nip developing on people very quickly so we were all trying to play close attention to each other's faces.

After a short flight to Camp 2 we immediately set to work.  This was to be our main camp complete with a dedicated survey grid and overflights by NASAs Operation IceBridge, our AEM system below a Ken Borek Basler (retrofitted DC-3), and the DTU Twin Otter carrying ASIRAS, an airborne version of CryoSat-2. As aircraft overflights could start immediately we set about building the radar corner reflectors we had made and shipped up.  These reflectors strongly reflect RADAR waves back to the sensor that sent them (i.e. from ASIRAS). Because it was a cold windy day we built the reflectors inside as there really is not much worse than working with small metal pieces in -20C with a strong wind.

Putting together the 1m corner reflectors inside the cooking tent. Nothing is worse than working with small metal parts in a strong wind at -20C.

We braved the elements outside to build the stands as they were rather large to fit into the cooking tent.
I was glad I had marked the wood and predrilled the holes because it was a snap to put them together.

Putting together the corner reflector stands.  I had mocked these up once in Edmonton, pre-drilling all the holes, and labelling each piece of wood so that everything would fit together nicely and quickly.

The plan that we had agreed to with various other scientists (such as though involved with the NASA IceBridge Campaign was to install the corner reflectors approximately 360m apart, within a 400m x 60m measurement grid.  The grid would be in the middle of a 2km long measurement line where we would put out buoys and visual markers to help align the aircraft over the measurement grid.

Christian's sketch of the site layout with the grid, transect, buoys, camp and runway shown.

We setup one edge of the 400m survey grid and then worked up the center line and finally the outer edge.  We often use bamboo poles as markers as they are light and very strong. The reflectors were setup and then the transect was laid out.  We could nicely use the corner reflectors and the grid markers to line up our transect. Then using a handheld GPS we placed the ends of the transects about 800m from each edge of the transect.  AS you can see in the sketch above we actually ran out of space on the eastern edge of the transect due to a large lead, but we were still 700+ meters away from the start of the grid. One of the issues with using the handheld GPS to place the ends of the transects, and one of the general issues when using GPS for sea ice work is that the sea ice may be drifting.  At Camp 2 were were drifting some 800m/hr! So one of our transect legs was about 15m shorter than we planned. Measuring the 800m with tapes or ropes would have taken much much longer than just running them out and using the GPS for measuring the distance.

Christian standing proudly by the first corner reflector.

This was basically the rest of the first day at C2 as we only arrived around 2pm or so.
We had a simple dinner, though excellent (thanks for doing most of the cooking Christopher!, I especially loved the grilled cheese sandwiches!).

Enjoying a warm beverage during a well earned break.

The next day it was time to start measuring. We started by measuring the edges of the transects that extended from our survey grid.  The main idea was that we would delay measuring in the survey grid until the NASA P3 flew overhead (and hopefully the other planes as well) or as late as possible.
We started with just 5m spacing along the transects measuring the snow surface elevation with the construction laser, the snow depth. We also did drill hole measurements of ice thickness and bulk snow density measurements every 50m.

Around 1300 local time we stopped for a quick lunch break and heard the noise of a plane...it was the NASA Operation IceBridge P3. We watched a few passes and took a few photos but then went back in for lunch so that we could continue our measurements in the afternoon.

The NASA P3!

It seems that our garbage bags work well for directing the plane, as do the buoys which the NASA team could look at until take off (and even receive positions of on their Iridium phones). It also helped that the ice was drifting in the same direction as our survey transect was set up.

A DMS image of the survey line markers and corner reflector taken from the NASA P3. Credit: Dennis Gearhardt/DMS and Michael Studinger/NASA.

In all the P3 flew 10 passes over our survey line before continuing on with the rest of the days flight mission. It was great to see the P3.

Maps of the overpasses of the P3 flight. Credit: M. Studinger/NASA.

 We finished the afternoon with the second transect leg and called it a day at around 7pm.
Well that is all for todays post.  The next post will continue with Camp 2 as there's still so much to talk about!