Another 50:50 day

It is that time that you have all been waiting for. Anyone who was reading this blog last year will recall a lot of statements along the lines of “I’m sure we will get some data tomorrow” or “I will get some data soon. Well the time has finally come where I can say that we have collected some DATA! Yay!

Placing the 100MHz receiver in a borehole after taking test shots along the ice surface. Optimism is always wearing a sun hat even if there is no sun!

Placing the 100MHz receiver in a borehole after taking test shots along the ice surface. Optimism is always wearing a sun hat even if there is no sun!

We have had on average a 50% success rate so far. The drill is working in the sense that it is heating the water – more than it did last year – however, it will not recharge the 12V battery that is powering the heater, so it only runs for a short time. It has also been leaking hot water onto the ice and has created a rather large, bath sized hole beneath the sledge, which we have since had to relocate!

The 250MHz radar managed to collect 80m worth of data in a borehole, which then had to be scrapped because the transmitter lost power before we could bring it back to the surface to quality control the data – grr. The 100MHz radar has managed to collect several bits of data including 2 zero-offset profiles, and some coarsely sampled borehole tomography – until it decided that it didn’t want to play anymore and randomly stopped working part way through a survey.

We have however also managed to collect some inclinometer data with the fancy kit we have from Icefield tools. We shall be going up to the glacier this afternoon to collect some differential GPS data to locate the top of each of the boreholes, and from all of this data, I

Typing up field notes waiting for the radar to charge. Making the most of the lack of rain.

Typing up field notes waiting for the radar to charge. Making the most of the lack of rain.

can calculate some rough velocities. Here’s hoping anyway.

The seismic kit is currently…missing. We have suffered a little mishap with our shipment being mixed up with…French soap. I am still trying to track this down, but I have every confidence we will locate it. Still, it’s lead to a lot of jokes about using the soap to speed up the glacier ice velocity, taking a bath on the glacier, and using it as a tracer in the nearby Moulin field!

The mini moulin on day 2 - on day 6 this was twice the size!

The mini moulin on day 2 – on day 6 this was twice the size and <100m from our field site!

Aside from issues with data collection, the glacier is pretty slippery at the moment because it has rained the last two days, smoothing the ice surface, so crampons have been essential. I slipped on the ice yesterday, without my crampons, and now have a nice bruise to show for my troubles! We also have a lot of surface meltwater around us, lots of deep, slushy puddles to test how waterproof our boots are, and a potential Moulin forming by borehole 2. It’s all go here!

Return to the glacier

We have arrived in Tarfala! We arrived in the evening on Tuesday on a helicopter, shared with a group from Minnesota University.  We were missing a parcel of inclinometer equipment from Canada, but apart from that I assumed the rest of the kit was in Nikkaluokta after a quick glance. Never assume.

We marked the kit drop points prior to the equipment drop. The talented helicopter pilots at KallaxFlyg managed to hit the bullseye with the drill (on the X) and the kit (on the O)!

We marked the kit drop points prior to the equipment drop. The talented helicopter pilots at KallaxFlyg managed to hit the bullseye with the drill (on the X) and the kit (on the O)!

We spent the next morning testing the drill including all it’s components. We managed to get it flowing and heated up(!) and the heater was burning with clean fumes. We went up onto the glacier in the afternoon to locate a good spot for the field site and played a small game of naughts and crosses to mark out the drop points for the kit. We then spent the evening packing up the drill and fuel ready for transport.

Yesterday we walked up onto the glacier for a supposed equipment drop off time of 10.30. 1 hour later, we were contacted by the helicopter crew to say they would be on the way. So by midday we had (what we thought was) all the kit on the glacier. We met Rafael (Tarfala technician) at the edge of the glacier, in order to carry the drill rig across. The plan was that afternoon to drill the first borehole and set up to complete a VSP the next day.

The obligatory drilling photo. Clemens tries his hand at hot water drilling for the first time. The weather is good; the water is warm. It's a good day.

The obligatory drilling photo. Clemens tries his hand at hot water drilling for the first time. The weather is good; the water is warm. It’s a good day.

It wasn’t until we were stacking the equipment together that I noticed we were missing a vital component – the hydrophone string. And I later noticed we were also missing a seismic box. SO I spent the afternoon calling the shipping companies and helicopters to track this down while Raf and Clemens drilled the first borehole. We managed to drill 95m in around 2hours – a vast improvement on last year.

As a back up plan, we decided to do the radar survey first, instead of the seismic survey, and hope that the kit could be tracked. I am still waiting for an update on that. On the plus side, the inclinometer package was tracked down and delivered, so we can now measure the borehole directions!

The drill site in action.

The drill site in action.

Today, Clemens and Rafael have gone up onto the glacier to start the drilling. Unfortunately, I have a condition that makes me sensitive to sun exposure – so working on a glacier during the polar summer is not always the best plan! I am hiding in the shade this morning while the other two finish the drilling – which they can complete without me. The radar is on charge, and I will go up this afternoon to hopefully complete some data collection. I realise this phrase is slightly similar to one I frequently used last year, however this year I feel more confident that this will actually happen! Let’s just hope that isn’t in vain…

More updates to come! Hopefully we’ll be able to improve on our 50% success rate so far.

Irreparably Broken

Your equipment is irreparably broken. These are not words you want to hear 2 weeks before your shipment leaves for the final and most vital fieldwork season for your PhD research. Even though that precise phrase was not used, that was the gist of the email that I received yesterday morning. My heart and stomach felt like they were imitating a routine by the Olympic 2012 gymnasts.

It’s ok. I assumed there was a possibility that this might happened. I had crossed my fingers and hoped that this wasn’t going to be the case, but I guess you can’t fix equipment through will power alone. So what to do now? Plan B.

The inclinometer (the aforementioned equipment) is a vital piece of equipment measuring the deviation of the borehole from vertical. Without it, any other borehole data I collect will be pointless. It is not so much a case of if I should hire one, but where to hire it from and is it within budget. With specialist equipment such as this, there are not many places you can get the kit from. In this case, there is only one company, based in the Yukon. We are still in the process of finalising the hire, but it looks like we may have a feasible Plan B that is, more importantly, within budget. Phew!

More updates to come soon. Shipment leaves on 11th July, so not long to go now!

Practice Makes Perfect

Seismic Station

The seismic station set up at the end of our line. The geodes (yellow boxes) are both next to it as we are packing the kit away.

Now as I haven’t done any field Geophysics since last year, I decided that the best thing to do prior to going to the field, would be to complete a practice survey. This is especially important for seismic surveys, where set-up is extremely important, AND time consuming. It also gave me and Clemens a chance to see how we worked together – pretty well as it turns out!

We took the Swansea seismic kit out of storage and set up outside the back of the building. We won’t be using that kit in the summer, but it needed testing anyway! With 30m of space to play around it, it was not quite the same scale as a glacier. And with 20˚C (or so Clemens insists) temperatures and brilliant sunshine, it was hardly difficult Arctic conditions. But it is always better to test your survey skills in good conditions, before you start trying it in difficult conditions. Mood plays a big part in how well a survey goes.

We put the geode batteries on charge, and started by planting the geophones (receivers) 50cm apart from each other, starting at 4m along the 30m tape measure, and finishing at 27.5m. We then starting laying out the geophone cable, being careful to untangle it in such a way that it would not find a way to get itself back into knots again – cables have a magic power to do that you see. Once we came to plugging the cables in, we realised two were in the wrong place and one was reverse of what it should have been. First fail. But, we have now learned!

The seismic line, as seen by gawking eyes from the second floor of our building.

The seismic line, as seen by gawking eyes from the second floor of our building.

We then hooked up the cables to the geodes (information-sending boxes) and then turned on the laptop. After turning on seismodule controller – for recording seismic surveys – I realised the data on screen implied that when we made some noise (stamping) that the energy seemed to start halfway down the line and then travel towards us. I had set up the geophones in the wrong place. Second fail. But again, at least we made these mistakes quite literally in our back garden, and not during vital data collection time on the glacier.

After moving the geodes to the correct location, we started the survey. We took several shots to practice, with me on the computer and Clemens on the hammer. As much as I hate to admit defeat due to my gender, I know that I simply do not have the upper body strength to continually swing a 6.5 kg sledge hammer. But that’s why I have Clemens!

It took us over 2 hours to set up and almost 2 hours to fully pack up. In theory, this should be a bit quicker in the field when we get going, although being on ice it might even take longer, but I think I will have to readjust my field plan to include this set up time!

The Science Behind the Survey

So for those who are interested, here is some technical stuff, for a more in depth description of what I plan to do in the field, and why I am doing this.

The overall aim of this project is to measure the changes in the microscale air and water content stored between ice crystals. We can use geophysics to measure these properties as radar and seismic surveys are each sensitive to any changes. Each technique is differently affect by property changes, therefore for the best result, it is necessary to do both. In particular we want to see how the properties vary as we measure deeper into the ice.

The surveys we planned to complete were cross-borehole profiles (XHP), using two boreholes, one containing an energy source, and the other a receiver, measuring the energy output. These produce accurate measurements for each depth. However, last year we had many issues when we attempted the seismic XHP. I therefore decided to investigate alternative methods, such as the Vertical Seismic Profile (VSP). This uses 1 borehole containing receivers, and the source set up on the surface. Logistically, this is easier, requiring only 1 borehole, however, the energy must travel further and therefore may not be as accurate.

Squinting at the computer screen as I set up the radar. Photo by Yoann Drocourt.

Squinting at the computer screen as I set up the radar. Photo by Yoann Drocourt.

I modelled the results I would get, using synthetic data so I could control the inputs. As expected, I found the speed of seismic energy depends a lot on the air content of the ice, whereas the radar energy is affected by both. The XHP model was more accurate for measurements deeper in the ice. However, the VSPs still produced a good result. The ability to obtain data we need, in addition to the improved logistical ease of collecting data in a VSP survey, lead me to decide that this was the best option to ensure data collection this time in the field.

A more realistic view of the practicalities of seismic data collection. Hoping for better weather next time!

A more realistic view of the practicalities of seismic data collection. Hoping for better weather next time!

We have since hired a hydrophone string to use in the field. This has 24 receivers separated by 1m, which is non-adjustable. The acoustic energy source will be a hammer blow at the surface. The survey will involve multiple shots at the surface, with at least 12 lines of shot locations – like a clock face. Each shot location needs to be repeated several times so we can average out the noise.

All this pre-planning should hopefully lead to better data collection in order to calculate what we want. Improving the calculation of ice properties, like I am attempting to do here, should inevitably lead to the improved production of ice flow model, to see how ice should react to future changes in climate -but that is a LONG way off yet!

The Calm Before the Storm

We have confirmed our fieldwork dates! We will be travelling to Sweden from the UK on 22nd July and returning to the UK on 14th August. We have begun collecting equipment and will soon be packing it up ready to be shipped on the 15th July. It is vital to test that the equipment works before sending it to the field in order to ensure data collection is successful.

The hot water drill and radar have both been sent away for repair, and the inclinometer tool is also currently on it’s way to be repaired. The kind folks at Icefield Tools will hopefully get that fixed and back to us before we need to ship it away to Sweden! If I look at last year as a learning experience, I can see all the things that can go wrong – because they probably already did go wrong. Testing equipment before I leave is therefore a top priority to avoid any further issues.

Caught in the act: Yoann takes a quick nap while waiting for the drill to work..

Caught in the act: Yoann takes a quick nap while waiting for the drill to work..

In addition to logistical issues, I also have to consider the actual data that I want to collect. Last year, the aim was to collect two sets of cross-borehole surveys, one for seismic, one for radar. This is fairly simple for radar as we own the kit and it easily fits into boreholes. For seismic, we had hired a sparker source and a geophone that clamped to the side of the borehole, borrowed from Queen’s University, Belfast. The issue with this was the sparker had a 10cm diameter, and the clamping arm for the geophone could only extend to fill a 15cm borehole. The borehole diameter could only be controlled by the speed of lowering the hose of the borehole drill. In an ideal world (where the drill worked) this might not have been so bad, we just would not have been able to use the spaker in the same hole as the geophone. However it took us so long to drill the hole for the sparker, the previous hole had closed up. Sigh…hard work!

But wait! “It’s hard” is not really a valid scientific reason not to do a survey? Correct. So this year I have spent my time completing forward modelling for seismic surveys to predict the outcomes of Cross Borehole Surveys, and the alternative, a Vertical Seismic Profile (VSP), which requires only 1 borehole, with the receivers in the borehole, and the source on the surface.

So, we have hired (from Geomatrix) a hydrophone string (measured the pulse of acoustic waves in water) which has 24 receivers – great, now we don’t have to lower it down 1m to take each measurement!! We can get 80m worth of measurements (at a 50cm spacing) in 8 different depth measurements. It’s so fast! We will also use several shot positions, so that our GPS positions will look like a star with arms out like a clock face. This is called a multi-azimuthal walkaway VSP.

We also have a new laptop to use with it as well! Well, it’s not entirely new, since our radar kit communicates to the laptop via a parallel port, we had to get a 5 year old model, but it is an improvement on the old one we have affectionately nicknamed “the brick”.

Photo by Torbjörn Bergelv. Early snowmelt caused by hot air from the east has exposed the ice surface on Storglaciären (13th June 2013)

Photo by Torbjörn Bergelv. Early snowmelt caused by hot air from the east has exposed the ice surface on Storglaciären (13th June 2013)

The good news is the melt has come early this year and ice is already exposed on the glacier. With any luck we should have some meltwater to use when we get there in July.

Next challenge – finish testing and pack up the kit. Not long to go now until fieldwork take 2!

Storglaciären: Return of the Glaciologist

Now I am aware that last year, there was a lot of promises to collect data via this blog, and optimism that the next few days would provide this. However, it seems this was not to be. In the last few days, mother nature cut us off from the glacier, flooding the bridge and therefore our only access.

Lillsjön lake, by Tarfala Research Station, shown at the end of June, prior to snow melt (left), in early July after snow melt (centre) and flooding the valley after a day of heavy rainfall (right). This flooding prevented us from travelling onto the glacier.

Lillsjön lake, by Tarfala Research Station, shown at the end of June, prior to snow melt (left), in early July after snow melt (centre) and flooding the valley after a day of heavy rainfall (right). This flooding prevented us from travelling onto the glacier for 2 days, and delayed our ascent on the third.

The weigh of the water, in addition to any ice from upstream, caused the wood supporting the bridge to crack. The excess water flooded the valley so much that we were only JUST able to cross to the other side safely. We contacted the station over the radio about the bridge and it was repaired enough for us to cross back safely at the end of the day.

The weigh of the water, in addition to any ice from upstream, caused the wood supporting the bridge to crack. The excess water flooded the valley so much that we were only JUST able to cross to the other side safely. We contacted the station over the radio about the bridge and it was repaired enough for us to cross back safely at the end of the day.

The following day, after waiting until 10am, the waters receded enough for us to cross, although as you can see from the photo the bridge was not exactly stable. We thought that our luck might have changed for this last day.

Arriving at the drill site, we realised that the bad weather must have included a strong katabatic wind. Our generator (35kg) had been rolled onto the side of it’s square frame; two box lids and an entire zarges box had rolled off down the glacier, as had the (mostly empty) antifreeze barrel. Most of the missing items were located again, and with some gentle encouragement, we managed to get an unhappy generator working again.

In addition to this, the drill broke completely, one of our boreholes had closed beyond use, and the radar was also not working. All we were left with was the borehole geophone and a sledge hammer, in a >30cm wide, 22m deep borehole. In theory, for the geophone to work, it needs to be able to clamp to the sides of a borehole (max clamping width = 15cm). The hope was that the geophone might also collect data if it pretended to be a hydrophone (http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=hydrophone). Unfortunately, despite our best efforts to collect data with everything we had left, we simply did not have enough time.

We did manage to collect GPS readings of all boreholes and the seismic line using a Trimble differential GPS. GPS uses satellites to calculate the position of the mobile unit – the more satellites that the GPS can “see”, the more accurate the positioning  The accuracy of this particular GPS is further improved, as the mobile unit is calculated not only by satellites, by also relative to a base station. The base station is a second GPS unit set up at a precisely known location – in this case, the roof of a building in Tarfala Research Station. 

So, last summer did not exactly go to plan. However, I remain ever optimistic that this fieldwork will work. We have experience now, we know what can go wrong, and we know what needs fixing prior to arriving at Tarfala. Somewhat more importantly, INTERACT Transnational Access has yet again supplied me with the funding for the PIPS project (Physical Ice Properties of Storglaciären), so that I can travel to, and stay at Tarfala Research Station for the field season! THANK YOU!

So rather than just blogging from the field this time, I will also include you in the planning process.  The updates so far are that the hot water drill will be travelling to Kiruna by snowmobile this spring for a full service.  Unfortunately, Yoann will not be returning to Tarfala this summer; instead I will be travelling with a new field assistant, Clemens Schannwell. Clemens is an MSc student in the Glaciology Group at Swansea University; he is working with GPR data from Midtre Lovénbreen (Svalbard), analysing the glacier structure. In combination with spending a year studying in Fairbanks, Alaska, Clemens has experience in both geophysical surveying, and working in cold conditions.

Field Team #1: Charlotte Axtell.Second year PhD student at Swansea University. The face behind the blog, PI on the PIPS project, and an enduring optimist.

Field Team #1: Charlotte Axtell.
Second year PhD student at Swansea University. The face behind the blog, PI on the PIPS project, and an enduring optimist.

Field Team 2: Clemens Schannwell.MSc Student at Swansea University. Fieldwork Enthusiast.

Field Team #2: Clemens Schannwell.
MSc Student at Swansea University. Fieldwork Enthusiast.

We are looking forward to going back to Tarfala this summer and are hoping for better luck this season. In addition, we are doing everything we can to ensure the equipment is functioning correctly before we arrive at the station! Any useful suggestions to help make this field season as effective as possible are very welcome.

Bring it on Storglaciären, we’ll be back soon!