Now back in the UK, after a fascinating trip.  The helicopter finally made it to the iceberg on the last afternoon, which meant that the BBC could get the all-important aerial shots for the programme.  And so, on a slightly misty, but otherwise clear night we steamed away from the berg, back to Ilulissat to make our way home.  This has certainly been an extraordinary experience: a giant iceberg decaying before our very eyes, polar bears at every turn, with mist and fog swirling around adding to the surreal atmosphere.

Polar fieldwork can often be a bit of a lottery, especially when trying something new. Very often you come away with insights you would have never expected.  This is definitely one of those occasions.  All of the ship-based work was achieved, but very little of the iceberg-based activities came to fruition.  Looking back, though, it’s now clear to me that, had we been able to set up camp in the middle of the ice island, we would have missed out on some important observations of the dominant iceberg-ocean interactions.  Those observations are now in the process of being turned into hypotheses that can be tested using computer modelling, and possibly future fieldwork.

As for the filming activities, the programme will clearly take on a hue different to that originally planned.  But the Series Producer is confident that they have what they need to make a good programme, so both the scientists and programme makers can be happy with the outcome, and we couldn’t have asked for more than that.

This iceberg has proved extraordinarily difficult to board. We’ve been fended off by a variety of threats, often cunningly working in consort. The combination of fog and the threat of bears is a particularly effective deterrent to going “ashore”. The helicopter that had been planned to be used for transport around the iceberg has been held back by poor weather on Baffin Island, and it’s possible that it won’t be able to join us. On the other hand, we have made some real progress in understanding how icebergs decay in warmer waters, and also how icebergs affect the water around them.

Today we were able to pull alongside and land a science party, who succeeded in deploying some instruments, despite strong winds, driving rain and the coming and going of mist. It was a great feeling finally to set foot on the ice, after seeing others go ashore in the past, however briefly. At one point we had to make a temporary retreat back to the ship when a female bear and two cubs came shambling towards us out of the mist. In the event they showed little interest and wondered off, although another animal was quietly snoozing several hundred metres away. For researchers used to working in the Antarctic, having polar bears wondering freely around one’s study site adds a piquancy missing in our usual fieldwork.

Tomorrow is our last day, and so we are keen to make the most of it. Overnight we plan to undertake the last scan of the face of the iceberg, which uses multibeam sonar imaging to record the shape of the submerged face, and laser scanning to do the same for the exposed ice cliff. These are then meshed together to generate an impressive image of the entire ice wall. This will be the third entire scan of the iceberg, and will help show how the shape has changed during over the last ten days. One thing we can be sure of is that the changes will be substantial – we were part of one of them when the ice we were moored to broke out. The scans will mean that we can estimate the iceberg’s volume change due to the breaking of ice from the edges, and the detailed shape of the wall will be evidence for the mechanisms for that ice loss.

Despite the difficulties faced by the expedition, the coming together of different groups to tackle aspects of the problem of iceberg decay from a variety of different points of view has been very exciting. And the fact that we have divers on board, keen to dive down the ice walls, has offered opportunities for unique experiments. The mix of different expertises has led to fascinating discussions, and to some wonderful datasets ready to be analysed.

We’ve been spending a few days prowling around the iceberg trying to find a suitable spot for landing. The weather has varied between days of glorious sunshine, but with wind high enough to make a swell that prevents mooring alongside, to calm days with fog and misty rain. Pulling alongside in any sort of swell risks damaging the ship’s side: on one occasion one of the crew had an unpleasant awakening with the wood of his wardrobe splintering as the ship’s side was pushed in a few inches during a particularly vicious bump. Attempts to land using small boats in inlets have been parried by strong river flows from the surface of the berg. Places that look good to land are often compromised by a large ice foot jutting out below sea level. These features can be one or two times the width of the ship, and if they decided to break off and float to the surface while the ship was moored above them, the situation would become very serious. One way and another, this particular iceberg seems to be determined to hang on to its secrets.

Ship-based work has been progressing well. We’ve finished an oceanographic survey around the iceberg, using the ship during the night when it’s not been used for other activities. These data will need careful analysis, but one feature that has been very obvious is the sharp change in water temperature and salinity at a depth of fourteen metres. This thermocline, which in this area is very near the surface, goes hand-in-hand with a change in density, and it’s on this density interface that we have seen strong internal waves. Internal waves are just like the waves on the surface of the ocean, except that they are under water. The characters of surface waves and internal waves are very different, as they depend on the change in density across the interface: the change in density across the thermocline is only 0.4% of the huge difference between water and air. Those internal waves have a period of several minutes, and can move the thermocline up and down by over five metres. When they arrive at the iceberg, they wash up and down the ice wall and might make a real contribution to the rate of melting. They were even felt by one of the divers when they were filming over the ice foot. Oceanographers normally only see the behaviour of the ocean through the lens of their instrumentation – it’s really exciting to listen to the reports from divers who actually experience these effects first hand.

Yesterday we finally managed to moor up alongside and get some instruments deployed on the ice surface, and also some fuel for use by the helicopter pilot who’s patiently waiting on Baffin Island. Whenever a group is working on the ice, we have a team of watchful observers on the ship, keeping an eye out for polar bears. There was one animal moving around in the vicinity while the moorings were being installed and while the instruments were being deployed, but it kept a healthy distance from ship and all was well. We’ve since had to move away from this mooring point, as the ever-changing circumstances became awkward again. There’s no doubt that getting onto the iceberg has been a great deal trickier than anyone ever imagined, but we’re optimistic that we’re going to get back “ashore” and win some great insights into the decay of these enigmatic leviathans of the ocean. Whatever else it is, it’s a great adventure.

Scientists have a habit of looking at instruments and burying their themselves in data. This is all well and good for many, but for environmental scientists it sometimes pays to lift your head and look around. This came home to me very powerfully yesterday when we were circumnavigating the iceberg to do the scanning work, and spending a lot of time staring at the ice cliff, speculating on the various processes responsible for creating the features that we were seeing.

Ice cliffs have always struck me as some of the most stunning natural structures. The ice fronts of “our” iceberg are especially chiselled-looking, as if they’d been hewn out by a cubist sculptor. A freshly calved parts of the ice front are particularly sharply featured. Streams of surface melt run off the berg every few tens of metres, mostly small streams and trickles, but larger flows are occasionally also seen. The upper surface undulates gently, with continuous ice hummocks and ridges, perhaps ten or twenty metres across and a metre or two in height. The small streams we see at the edge of the cliffs run between the hummocks, with the occasional pond or small lake visible a hundred metres or so onto the berg.

Planning for polar fieldwork always has to remain flexible, and this work is no exception. The present idea is to moor the ship to the iceberg as soon as possible, and to start getting fuel and equipment ashore. What’s been delaying us is the poor visibility and the sea swell. The visibility means we can’t see bears, and the sea state makes it too dangerous to off-load personnel. The good news is that the weather conditions are due to improve over the next day or two; we shall have to wait and see what happens in reality.

We arrived at the iceberg this morning at 0700 Greenland time. The rather cool, overcast conditions couldn’t dampen the enthusiasm of BBC crew and scientists alike. Yesterday was a day of intensive preparation for the scientists, assembling and testing instruments, and being filmed now and again.

Everything is now ready, and the arrival at the iceberg signalled the start of a circumnavigation to obtain a combined laser-scan of the ice cliff and multibeam sonar scan of the ice below the waterline. The aim is to create a continuous image of the entire edge of the iceberg, so that it can be compared with a similar image to be obtained at the end of the visit. Using the images, it’ll be possible to find out how much ice has been lost from the perimeter during the period of the stay here.

Other activities have included a trial deployment of the CTD profiler, an instrument to measure the properties of the water around the iceberg, and the deployment of a Waverider buoy, used to monitor the waves that the iceberg will be subjected to. By measuring the way the iceberg tilts and deforms in response to the waves that it’s exposed to, it will be possible to work out the stresses the berg is under from wave activity and the likelihood of its breaking up.

Today the scanning has been interrupted by three separate polar bear sightings, which led to huge excitement on board and the dash to the upper deck of several hundreds of thousands of pounds worth of camera equipment. This early exposure to the bear population has led to a great deal of enthusiasm from those who will be staying on the ship, and a similar amount of trepidation in the “iceberg group”, or “bear-fodder” as they are now being termed.

Povl and I are making the short hop up the west coast of Greenland from Kangerlussuaq to Ilulissat, where we will board the ship to take us to the iceberg.  The flight is only forty minutes long, but offers fabulous views of the western edge of the Greenland Ice Sheet.  To the east the ice sheet rises up towards the interior plateau; to the west lies Baffin Bay and, eventually, Canada.  The magical area is the bit that lies between, where the ice ends, and the exposed land gives way to the sea.

The junction between ice sheets and the ocean has always held a fascination for me – it’s what I’ve spent my career studying in the Antarctic. It offers some of the most stunning scenery, with the grandeur of huge floating ice shelves abruptly ending in the sheer drop of the ice cliffs, with the sea below decorated with a scatter of sea ice.  Conditions in all but the far north of Greenland are different though.  Here the climate is warm enough for the ice sheet to end short of the ocean and not to go afloat to form ice shelves.  But the landscape is equally magnificent.

We fly over a glacier whose off-white surface is incised by hundreds of crevasses, all aligned in swirls, and giving a texture reminiscent of elephant skin.  Where the glacier ends we can see the melting ice feeding streams coloured white by their load of rock flour – material from the glacier bed that has been pulverised by the passage of the ice.  Between the ice and the ocean the landscape is low and undulating.  Inlets from the sea form a filigree of waterways that have a colour ranging from the white of the melt water, through malachite-green and every shade of turquoise, before taking on the dark blue of the ocean.

As we fly closer to the coast we get to see our first icebergs. Small bergy-bits calved from the nearby Jacobshavn Glacier, one of the many Greenland glaciers that does make it all the way to the ocean before ending in a crumbling wall of ice.  We decide we wouldn’t want to camp on what we see below, with the larger bergs only a few tens of metres across.  From overhead we can easily make out each iceberg’s broad extent below its waterline, blooming out like an eerie jellyfish, the iridescent-green contrasting strongly with the bright white of the exposed ice above.

We fly over Ilulissat.   The buildings cling to the steep slope down to the harbour, and are painted in different colours, dramatically extending the palette of the landscape. We have two nights here, before boarding the MV Neptune.  Then there will be an intensive period of prepping equipment before we get the first glimpse of “our” iceberg.  Exciting times ahead.