Thursday 10 April 2014

Planes, planes, everywhere!

Whilst we were out on the camp we had flyovers from three different aircraft carrying various geophysical instruments to measure the sea ice. Everyone got very excited by the DC3 (the same one that took us from Qaanaaq to Station Nord) towing the EM bird underneath. The EM bird is a torpedo shaped device that measures the sea ice thickness through electromagnetic sounding. The DC3 tows it on a cable 50m or so beneath the aircraft, only 15m above the ice surface. The cable makes a whistling sound as it cuts through the air and makes for a very dramatic sight.

At the same time as the DC3 we also had the TF-POF Twin Otter carrying a laser scanner and ASIRAS. ASIRAS mimics the operation of the instrument onboard CryoSat-2 and is very useful for linking what we see on the ground with what is seen on the aircraft, and what is seen by the satellite itself.

Then a couple of days later, on 1st April we were treated to multiple fly overs from the NASA Operation IceBridge P3. This is the biggest of the three aircraft and carries a comprehensive set of instruments for assessing the state of the sea ice.

Combined with the measurements that the ground teams made – thousands of snow depth measurements, ice thickness measurements, our radar penetration measurements – we have collected an incredible wealth of data on this sea ice floe. There will be a lot of analysis to do but it should shed some real light on how we measure sea ice using CryoSat-2 and hopefully even improve our methods.

Camp life

The camp itself was very well equipped. Marc and Petter did a great job taking care of us. There was always hot water for drinks and the food was really good considering it all came dried out of bags! When everyone got crowded into the domed mess tent it got really steamy from all the food, hot drinks and our frozen clothing. One downside was that it wasn't possible to dry or defrost clothing - Scarves and balaclavas got really soaked (and frozen solid) from breathing, and after a few days the inside of boots started to get a little damp as well – not good for cold toes (or trench foot!) Here's a picture of the camp. You can see the small sleeping tents on the left, the workshop tent in the middle where we could store equipment and briefly escape the wind, and the mess tent on the right:

And here we all are getting cosy in the mess tent for our evening meal:

By far the worst part of the camp was sleeping. The sleeping tents weren’t heated so getting into the multiple sleeping bags was really unpleasant! I slept with my face totally covered up by a neck scarf and a hat pulled over my eyes. This was great for keeping my face warm but they got totally frozen up on the outside from breathing and then froze to the top of the sleeping bag. The only thing more unpleasant than getting into bed was getting out again the following morning. After you’ve managed to get your face unstuck you have to crawl out of your multiple sleeping bags into a freezing tent to get dressed. Over night your warm breath freezes to the tent, so by the morning the inside of the tent is covered in snow, and if you knock it at all you get snowed on! But it was certainly an experience and we'd both do it all over again! The tents looked especially uninviting after the bad weather:

One night it was hard to get to sleep for another reason – we could hear the ice creaking and groaning. The thought of a crack opening up close to the tent was a little worrying, but highly unlikely (we think)! Marc and Petter surrounded the tents with a trip wire for bears and there were 2 guns on site. Whilst we were out we tried to keep looking around every few minutes in case we were being approached or stalked by a bear. As Marc remarked, if you’re digging a snow pit, wearing a black down jacket, to a bear you look a lot like a seal coming up for air.

We had a small loo tent, which was a relief, in particular for Rachel! Here’s a pretty awesome polar potty sunset pic:

Tuesday 8 April 2014

Making measurements

As soon as we arrived, we got to work building the set up for our experiment. Just as we had practiced in Qaanaaq we assembled the antenna frame, arranged the Network Analyser in its thermal box and mounted everything on the sled. It took a while in the afternoon to get the generator working but that first day we worked until about 10pm and got the first few radar shots done. The sun didn’t 'set' until about 1am, and it never really got dark so it was very easy to keep on working until late.


30th March - Today was a bit trickier. On site we had 3 generators and for some reason - possibly the cold, possibly because they had been shaken around a bit too much in transit – none of them wanted to run for any extended period of time! This was also the day that the rest of the ground team went on a day excursion to a northern site and Ewan came to the ice camp to help us make measurements. Luckily it wasn’t a wasted day as we made a load of snow depth measurements, and the generator eventually started working so we managed to make some radar shots late in the evening.

31st March – we had a really good day. We managed to get one of the generators to run for a whole day non-stop! Taking our radar shots of the sea ice and digging the snow pits to make notes about the snow layer characteristics quickly became a routine and we got really efficient at using our time effectively, so that neither of us was stood around for too long getting cold. The time absolutely whizzed by and we ended up working from the morning all the way through until about 10pm.

In the afternoon the weather set in a bit again. The wind picked up and it began to snow. It wasn’t too cold though – the combination of the low cloud and fresh snow meant that the temperature stayed reasonably high (when it was still with clear skies the air temperature could get down to -30C to -35C). The cloud and snow also meant that the visibility dropped significantly, from 10s of kilometres to a few hundred meters. We were working at the second corner reflector site, about 300m from the camp and when the visibility dropped we got quite paranoid about polar bears – we were stopping and checking around every few minutes. We had our whistles to attract the attention of Marc and Petter, and if it really got close we also had some bear bangers (small fireworks that you launch off a pen-sized device) to put off any curious bears. Here you can see how low the visibility can get with even mild wind and snow:

An interesting atmospheric effect also happens when there are ice crystals in the air - the suns light gets refracted and forms a ring around the sun, commonly known as a 'sundog'. Here's a pic:

We made a lot of measurements, and dug a lot of snow pits. It sure makes your back ache! But we got a really god idea of the variability of the snow layer on top of the sea ice. This is important for us because understanding how the radar interacts with the snow layer is essential for making the best measurements with the CryoSat-2 satellite.

Off to camp!

March 28th - The weather cleared up in the evening, so Christian, Bruce, Marc and Petter flew out to locate a site and set up the ice camp. It was windy where they landed and apparently it was quite a lot of work to get some tents up. The following morning Rachel, Chris, Justin and myself joined them on the ice. Here's a picture of the sea ice off the north coast of Greenland, and then a picture of the camp as we approached:

They had picked a big multi-year floe – thick ice (3-5m) that had survived last summer’s melt season. Multi-year ice tends to have much more topography than first-year ice and this floe had a very varied surface. There were fairly large pressure ridges surrounding us where the floe had be crushed up against neighbouring floes, large flatter areas where last summer’s melt ponds had been, hummocks where last summer’s ridges had been, and everywhere there were wind blown ice drifts and sastrugi. Sastrugi are wind blown erosional/depositional features of the surface, and appear quite similar to ocean waves - 10s of centimetres high and a few meters long - but frozen in time. This pic that Rach took gives an idea of the topography of the ice floe:

Most places there was a fairly thick snow layer – the deepest we measured was around 90cm but on average it was maybe 30 or 40cm. The top layer tended to be a firm crust called a wind slab that was maybe 10cm thick and made walking around much easier. About the bottom 10cm of the snow pack tended to be depth hoar – larger crystals formed by sublimation of water vapour due to the temperature gradient between the top and bottom of the snow pack. The depth hoar is much more loosely packed than the top layers (often the crystals aren’t bound at all) and the effect of the hard crust and the greater amount of air left between the spaces of the depth hoar crystals meant that your footsteps echoed in the snowpack as you walked around. Here's a close up of the depth hoar crystals, thumb for scale!

The flight out to the sea ice was very exciting: the four of us, plus a load of the scientific equipment all packed into the back of the Kenn Borek Twin Otter. We had excellent views of the north Greenland fjords and the sea ice all of the way. When we arrived at the camp the pilot descended to around maybe 100m and made multiple passes over the floe to get a better assessment of the landing conditions. The landing itself was great fun, a bit bouncy but if you put out of your mind the possibility of the plane falling through the ice then it was calm enough!

When we arrived there was a little bit of wind, but it quickly died down. By the late afternoon/evening of the 29th it was very still and sunny. To the south we could see the mountains of northern Greenland and Cape Morris Jesup, the most northerly land on the Earth. Here you can see the mountains:

Thursday 3 April 2014

Weather days

27th March- Marc and Petter arrived late last night in the Kenn Borek Twin Otter with all of the camping equipment and supplies. After a late supper we sat down and went through our plans for the ice camps, and they briefed us on some of the practicalities of the camp itself. It all sounds pretty promising: a heated mess tent, a workshop tent for storing some equipment and 4 two-man sleeping tents which aren’t heated but we have some pretty serious sleeping bag arrangements.

By the time we left the bar the wind had got up and on the walk back to our accommodation we were treated to a pretty serious snow-blasting. Unfortunately this was a sign of the bad weather to come. This morning it has been completely overcast and snowing a bit – the pilots can’t fly in these conditions so we’re stuck on base until it clears. We should have another update from colleagues with satellite imagery of the area this evening but there are no truly reliable forecasts for this area.

So another day of delay. Let’s hope it clears up by tomorrow… Here's Christian looking a little windswept:

28th March- The weather cleared up a little overnight and this morning but it’s deteriorated again – we just attempted to walk down to the sea ice in the local fjord but the wind picked up again and we turned back.

An interesting side story has been developing whilst we’ve been here though. One of the Danish Army dog sledding teams – there are six teams that patrol Greenland to maintain Danish sovereignty (“keep out the ugly Norwegians” as one of the base staff put it) – are having a bit of trouble. They’re less than 40km from Station Nord but they have run out of fuel and are on half rations. There is so much powdery snow, and no pre-made tracks, so the dogs can only get them about 5km per day and are getting very tired. Obviously these guys are incredibly well prepared and well trained, but it’s still a very difficult situation for them. The first night we were here they went out on skidoos to try to mark out a track for the dogs to use – two of the three skidoos broke down and one is still stuck 33km from the base. They are making contingency with our pilots to make a barrel drop of food and fuel to keep them going a bit longer, but so far the weather has prevented this.

Anyway, it’s fairly disheartening to be stuck here. The base is great – the staff are brilliant and it’s very comfortable – but that’s not why we’re here! Rachel and I put in a huge effort to get us here and to think we might not be able to get all the data we want is pretty frustrating.

But here's an obligatory frosty beard shot to lighten the mood ;)

Arrival in Nord

26th March- Here's a pic with our host in Qaanaaq Hans Jensen as we were leaving to get on our flight to Station Nord:


We arrived up here in Nord (81.5N, 16.6W) after a really nice 3 hour flight in a Kenn Borek DC3. It was originally built in 1941 and took part in Operation Market Garden but the flight was very smooth, if a little noisy. Here's our Station Nord selfie:

Nord is a very interesting place! We had a guided tour from Tom, one of the more senior guys up here – he has been up here for 21 of his 26 month stint. There are only five guys based up here permanently but the base itself covers a fairly large area and includes 35 separate buildings – workshops, garages, stores, quarters, a mess, a bar, even a small but surprisingly well-equiped vet’s room to keep the camp’s two dogs in good health. One of the dogs is a retied Greenlandic sled dog and the younger one is a sled dog from the Danish military, and they’re absolutely great. Until a few years ago they had a sled team based here permanently but it was too costly to keep it going especially when skidoos will do the job. Here are the dogs snacking on some dried mackerel, and our dorm for our stay at Nord:

Today we have been checking through all the equipment and planning as we’re awaiting the arrival of the rest of the team in a Kenn Borek Twin Otter, hopefully sometime later this evening. There was a pause this afternoon however as we watched the arrival of a Danish C-130 Hercules containing a four star general, and then a huge Ukrainian aircraft landing. The Ukrainians are supplying Nord with fuel as well as new fuel tanks.

Then, depending on weather of course, the plan is to attempt to establish the camps tomorrow – first  our camp managers Marc Cornelissen and Petter Nyquist will be flown out to locate a suitable site, and begin setting up the tents and preparing the runway. Then later the science teams will be taken out onto the ice camps as well.  At least that is the plan – we’re running a little behind schedule (about a day) but if we get out tomorrow that will still be 5 nights camping on the ice.  

The sunsets are fantastic when you're so far north, because they last for absolutely hours. Here's a couple of pics from the first night in Nord:

Monday 24 March 2014

Time to go!

Around lunchtime today we will be getting picked up by our colleagues arriving from Resolute, northern Canada, in a plane filled with all of the stuff we’re going to need over the next 10-12 days. And it’s going to be quite the 10-12 days! During that time we’re going to be based at Station Nord, then spending up to 8 days camping on floating sea ice that’s a few meters thick, hundreds of kilometres from rescue. We’re looking forward to seeing what it’s like to land on the sea ice in a small plane! There are going to be six scientists on the ice, including two of the UCL team at any one time, along with our two camp managers. The ground teams will be making detailed observations of the sea ice and snow on the ground. At the same time there will be three planes in the area making measurements of the sea ice with a number of instruments. The planes can record the thickness of the ice and snow, take high resolution photographs, take detailed laser scans and much more. About 3 or 4 times a day, CryoSat-2 will shoot from horizon to horizon, 730km above our heads and moving at 7.5 kilometers per second. Needless to say it will be the culmination of a lot of effort from many people!
We’ve had a really great couple of days prep here in Qaanaaq. Yesterday we spent a few hours pulling each other around on the sled on the sea ice, to get a feel for how much effort it will be hauling the radar to our survey sites. It turns out it was easier than we anticipated, although the conditions here are very good because there is very little snow on the sea ice. We even had time to stop for a cup of tea by one of the icebergs that serve as Qaanaaq’s fresh water supply during the Winter.

 Yesterday we assembled the whole radar set up down on the sea ice and made some proper practice measurements. Hans Jensen gave us a lift to the ice in his car, then we assembled the radar and off we went. The local sled dogs were very interested in what we were doing (they probably thought we had food). It went extremely smoothly and we managed to make some very handy measurements to test whether our experiment plan will actually work. Good news, it will! We also did a complete run-through of all the experiments we will do in the field, including all the different radar measurements and digging pits in the snow to look at layering and snow characteristics. Hans took some great photos of us in action:

And so our first stint here in Qaanaaq is over. We’ll be spending some time here on our return back to the UK, waiting for the one flight per week and madly analysing all our data (fingers crossed!) There really isn’t a nicer place to be waiting. Whilst it’s been a great place to do our preparations, it’s also been an incredible place to have the pleasure of spending some time, and everyone has been extremely friendly. Not many people get the opportunity to come up here and we’re all feeling very lucky that we’ve had the chance.
Not sure how easy it will be to blog from Station Nord. But hopefully we’ll be able to provide a few updates whilst we’re there, maybe no pics though.