EGU Image of the Week: Algal blooms on GrIS

A short article I wrote for the EGU blog about biological darkening of ice and snow was posted last month. The article was built around an aerial view of our 2016 field camp on the Greenland Ice Sheet, where large areas of dark ice are clearly visible.

Aerial view of the field camp in July 2016

The dark colour is due to a collection of dusts, soot and algal cells, with the algal cells doing the bulk of the darkening. A second figure in the article shows the algal cells under the microscope along with the spectra of reflected light from the algal ice surfaces. This was one of several EGU blog posts about icy biology, including this one and this one!


Nouvelles Explorations Festival, Royan

Arriving in balmy Royan (France) straight from a frosty ice camp in Greenland was a welcome shock to the system. The small seaside town was home to a five day celebration of geographical and intellectual exploration – the Festival des Nouvelles Explorations. I had the pleasure of talking about icy science on Thursday afternoon and discovering some truly amazing work being done in the fields of virtual reality, art-science fusion, cyber-security, drone technology and conservation. Three short videos below explain some of the work on show at the festival.


New spec-tech! A smartphone-based UV spectrometer

In our new paper we report on some novel tech that uses the sensor in a smartphone for ultraviolet spectroscopy. It is low cost and based entirely on off-the-shelf components plus a 3-D printed case. The system was designed with volcanology in mind – specifically the detection of atmospheric sulphur dioxide, but may also have applications for supraglacial spectroscopy. As far as we know this is the first nanometer resolution UV spectrometer based on smartphone sensor technology and the framework can be easily adapted to cover other wavelengths.

This follows on from a Raspberry-Pi based UV camera reported in Sensors last year which was recently adapted to sense in the visible and near-infra-red wavelengths for use on ice. The plan now is to compare the images from the Pi-cam system to those made using an off-the-shelf multispectral imaging camera that detects the same wavelengths. A report of testing this camera system for detecting volcanic gases is available at Tom Pering’s blog here.

Raspberry-Pi and smartphone based spectroscopy could make obtaining high-spectral resolution data a real possibility for hobbyists and scientists lacking sufficient funds to purchase an expensive field spectrometer. The system is also small and light and therefore more convenient for some field applications than the heavy and cumbersome field specs available commercially and can easily be mounted to a UAV.

Storm at Camp Bloom

Summer 2017 seriously challenged the idea that summer in SW Greenland has a reliably stable, clear, dry meteorology. Our field work was characterized by unpredictable swings between weather extremes from blizzards dropping 1ft of snow in an evening to bright sunshine and low wind, to rain and tens of centimeters of surface lowering in a few hours. Most of this was inconsequential and actually scientifically very interesting since we experienced what would normally be a year’s worth of surface change in a few weeks. However, we did have to deal with a particularly vicious couple of days of unexpected storm… Here are the notes from my field diary…

Unseasonal snow early in the trip (ph. J Cook)

19th July:

Wind steadily increased through afternoon with frequent periods of heavy rain. No real work got done b/c too windy for drones and spectrometer needs to stay dry. As dinner time approached winds continued to strengthen. Tedstone cooked a killer dahl while Stefan and I redrilled the stakes holding down all the tents and added extra guy lines to the mess on the windward side. Side of mess pushing in towards middle of mess during dinner. The fabric was looking a bit delicate and the flex in the tent wall was knocking things off the cooking table – boxes and stove etc gradually moved into the middle of the tent over about an hour as we ate. Downloaded data from AWS – winds averaging 48 kmph with much stronger gusts. Getting a little concerned about the longevity of the mess.

Early on in the evening, adding guy lines to the windward wall of the mess tent (ph. A Tedstone)


By 2300 the mess was pressing in and becoming quite concave during stronger gusts. Avoided going outside because of rain, but some tent maintenance was now essential. Intense surface lowering around the ply under the mess has caused poles to float in space – tent not so geodesic now! To try to counter this, poles on opposite sides of the tent were tied together with accessory cord to try to maintain dome shape. Outside tent, tags were tied up to the fly sheet to try to stop poles coming out. Predict chance of mess tent survival 40%, so all contents packed down into Zarges boxes and/or tied down, gas disconnected from stove, electrics and batteries dry-bagged and stored. Essentials moved to personal tents or stashed in dry bags for moving later.

The mess tent starting to get badly misshapen at about 2130 (ph. J Cook)

Tedstone went to bed, but almost immediately came back with ‘bad feeling’… Bang on. On cue, a strong gust ripped the tent fabric on the windward side, which was now bending inwards to touch the plyboard floor in the centre of the tent. Now no chance of maintaining tent shape. We evacuated the tent, thankfully the rain had died down, and watched the tent collapse inwards. Seeing poles bending and breaking, we pulled as many as possible out of their tags to allow them to flop safely downwards rather than pinging dangerously as they or the fabric snapped under tension. Zarges boxes pulled onto the edges of the fabric to stop tent flying away entirely.

The collapsed mess tent at about 0200 (ph J Cook)

Now early morning and personal tents also looking in poor condition, with surface lowering causing stakes to bob uselessly in shallow drill holes and strong winds bending the tents out of shape. No sign of storm passing Р front after front lining up on horizon and winds only getting stronger. Tom and Stefan looking very cold, so sent to their tents to get warm. Buddy system established: in event of any problems with personal tents, warmth etc Tom would get into my tent and vice versa, and the same for Andrew and Stefan. Tedstone and I extracted the drill and flights from the wrecked mess and redrilled holes to stake down all of the personal tents. Agreed that if one personal tent goes down, we call in search and rescue. Rationale was that once a personal tent goes, the others will follow and we then have no shelter. With no sign of storm abating the risk of exposure and hypothermia was not justifiable. However, both know chances of heli getting here soon are slim. No panic yet Рpersonal tents standing up OK and everyone dry and warm. At 0120, Tedstone and I went to our personal tents with agreement to reconvene and check all tents again in 2 hours, and also call back to the UK for up to date forecast.

0330 Reconvened with Tedstone – tents looking ok but storm still raging. Called Martyn (project PI) on satellite phone to ask for urgent weather forecast. Text response indicated clear weather after this storm, but could be a further 6-8 hours. Still satisfied with safety of personal tents, so 0430 back to tent to sleep with agreement to meet at 0730.

0730 Reconvene with Tedstone. Storm still strong and still looks heavy all the way to horizon. Back to tents to sit it out. Tried to snooze.

1000 Fetch stove and emergency dehy food from wrecked mess tent and cooked in porch of my personal tent. Tedstone delivered very odd breakfasts to very hungry researchers in their tents. Personal tents now looking ropey, so agreed to sit out until next break in rain, then repitch. 4 hours until next break in weather. By this time calmer weather was on the way. Cooked a second dehy meal for team and waited another 2 hours. Rain stopped and wind calmed through day. Once manageable, wrecked mess was packed down and entire camp rebuilt. No science done today!


On the ice with the BBC

The BBC Science team joined us for our first twenty-four hours on the ice this year, documented our work on algal darkening of the Greenland Ice Sheet. This started in the dusty town of Kangerlussuaq, where I took David Shukman, Kate Stephens and Jonathon Sumberg out to Russell Glacier. There, while I flew the drone to get aerial shots for the news broadcasts, the team did their ‘to camera’ pieces and filmed the melt pouring off out out of the glacier’s calving front. Here’s one of the short UAV clips showing the dramatic front of Russell.

The next morning it was onto the ice. We worked as quickly as possible to get a camp established, including the mess tent, personal tents, equipment cage and toilet. The BBC team filmed their on location pieces and Andrew and I flew the various UAVs and set up the science kit to demonstrate the measurements we’d be taking after the film team were gone. We all gave our interviews which were used for the 6 O’clock and 10 O’clock Evening News, the Morning News, Radio 4 and BBC On Demand. I also recorded a more light-hearted interview about living on the ice sheet which is linked to in the online news article.

Here’s the online article:

and the Radio 4 show:

The next morning the team packed up and shipped out back to dry land, leaving four of us (me, Andrew Tedstone, Stefan Hofer and Tom Gribbin) on the ice to start making our measurements of surface reflectance and algal growth. The picture below shows our camp from the air, looking roughly west.


One of our team, Tom Gribbin, also made this short film about the season using his GoPro camera.

Automating the boring (& expensive) stuff for Gradconsult

As a bit of an aside from the usual cold stuff, I’ve also gotten very interested recently in applying some scientific skills to streamlining processes in business settings. This led to a collaboration with the Sheffield-based business Gradconsult. They are contracted by Sheffield City Council to deliver a regional recruitment scheme called RISE SCR. RISE aims to grow the economy of the Sheffield city region by retaining graduate talent, while helping local companies find the right people to join their teams. This scheme has now gone through 12 cycles, growing each time.


The monthly reporting process had become long and arduous, with loads of data needing to be recorded for each individual business, application and applicant. This was taking the team several days every month and in the private sector, time = money. Automating the monthly reporting process frees up their time and enables them to deliver a better service to their RISE clients.


My first thought was to set to work in Python, naively thinking that an open source, free pseudocoding language was ideal for this purpose – I could almost see the pandas dataframes assembling in my mind. But it quickly became apparent that this was entirely the wrong road to go down. For a product to be useful to the business it has to a) be familiar, b) work on the company’s existing software, c) require no new specialist knowledge, d) require minimal interaction or modification, e) be transferable and immediately accessible to different team members and partners, f) be aesthetic and clear.

So, it was back to Excel. I admit I have completely binned Excel in favour of Matlab or Python over the past few years. But, it is industry standard for a reason – mostly self-perpetuating ubiquity, but also because it is a very simple interface. However, some things that would have been easy to code were a bit cumbersome in Excel, like finding unique entries in a dataset that satisfy several criteria.

Frontiers Paper: Albedo products from drones

A new paper, led by Johnny Ryan, shows that a consumer grade digital camera mounted to a drone can be used to estimate the albedo of ice surfaces with an accuracy of +/- 5%. This is important because albedo measurements are fundamental to predicting melt, but satellite albedo data is limited in its spatial and temporal resolution and ground measurements can only be for small areas. Methods employing UAV technology can therefore bridge the gap between these two scales of measurement. The work demonstrates that this is achievable using a relatively simple workflow and low cost equipment.

The fixed-wing UAV setup (Figure 1 in the paper)

The full workflow is detailed in the paper, involving processing, correcting and calibrating raw digital images using a white reference target, and upward and downward shortwave radiation measurements from broadband silicon pyranometers. The method was applied on the SW Greenland Ice Sheet, providing albedo maps over 280 km2 at a ground resolution of 20 cm.

An example of a UAV-derived albedo map from the SW Greenland Ice Sheet (Figure 3 in the paper)

This study shows that albedo mapping from UAVs can provide useful data and as drone technology advances it will likely provide a low cost, convenient method for distinguishing surface contaminants and informing energy balance models.