Guideline Geo : Ice and Snow, or maybe thaw

June 18 2021

It is August, the days are hot and the sun keeps shining. Perhaps like myself you are spending time somewhere between sweating in the field, on the beach, or trying to avoid most of the heat in the shade. But have you spared a thought for ice and snow lately? 'Brrrrrr, don´t mention it now, it ruins my summer feeling!' 'Oh yes, I think of ice, ice in my drink, all the time!' 'Are you thinking about climate change?!' We all get different associations, in high summer, when somebody starts to talk about ice and snow. I mostly miss it, a lot. Both for adventures. But also for our future. This article will be a mix of them both.

My ice and snow background

I live in Stockholm, Sweden, and have always done so, so snow and ice are a part of life. I remember my childhood winters as white and cold, with plenty of Snowmen and constant snow shoveling. Nowadays in Stockholm winters tends to be grey, wet and windy. Did I mention wet and grey? My shovel leaves the garage on rare occasions during the winter months of November to March. And yes, memory fails, but according to measured mean values, the amount of snow in Stockholm has decreased by almost 20% since I was a kid.

I love to ski, cross-country. I love to skate, on lakes and sea-ice. But the opportunities to do this in southern Sweden seems to constantly be decreasing. So, I am lucky to have an occupation which have given me the possibility to work with and travel to ice and snow elsewhere in the world.

I work with GPR, this is an amazing tool for so many fun applications and I have done so for the last +20 years. It all started in 1920's. But not for me.

GPR recap

GPR, Ground Penetrating Radar, in fact started as an investigation tool for ice, and not the ground. One of the first recorded surveys was carried out to determine the ice thickness of a glacier by W. Stern already in 1929. And from there and onwards GPR and its electromagnetic waves has been used for constructions, railways and roads, geology, lost objects as utilities and historical remains etc around the world. Easily explained, GPR works as a fish-finder on boats. Electromagnetic waves are transmitted and the back-reflection is received and stored.

Keep an eye on the snow cover

2005 was the first time I interpreted snow layer thicknesses from Northern Sweden. The aim of the investigation was to get a better grip of how much snow was actually thawing to water, running into creeks, and finally filling up the hydropower dams. I had convinced my husband (researcher within hydrogeology) to use GPR to map the snow layers in an ongoing water management project. He and his colleagues were used to check the thickness by core samples, giving spare data input to their model calculations of the water content. Now, instead they could mount a GPR equipment behind a snowmobile, go comparably fast and gather plenty of data from the mountain region above the waterpower dam. The GPR delivered, and measurements are still ongoing on yearly basis to map snow layer thicknesses and the variation in the same.

For the use of green electricity, from waterpower plants, this is essential knowledge for the discharge planning from the dams and GPR is used in many snow regions around the world to provide this input, combined with both sampling and laser scanning. And as a side effect the variation in snow cover can be used to model risks for e.g. avalanches. I am glad for the nice data and the application, but still think I should also do the measurements and not only the interpretations… Snowmobile is still on my bucket list. Or maybe do the same from a helicopter.

Bits and pieces of icebergs

In 2012 I talked to colleague, asking if I wanted to go to Greenland. He was busy travelling to some other exotic place on Earth. I said yes, without blinking and then asked what the purpose was. To find an airplane. Deep down in the ice cap. 900 kilometers from the civilization. This was the start of a series of trips to South-East Greenland. And what I still long for most, every summer. The possibility to live in a tent for weeks, experience a starting pitoraq (high speed winds on the ice cap) in a rolling tent with your favorite GPR antenna, amongst friends, eating freeze-dried food (with expiration date September 2037), is indescribable.

The plane is still un-found, but during these years the ice cap and surrounding sea has changed. The best coffee-drinking-spot has a magnificent view over the ice cap, the sea and the enormous icebergs. From 2012 to 2018 the icebergs have decreased in size, and what in 2012 was a huge island, is today only bits and pieces. The climate change is very visible. I hope we will return, for the plane, so I can use a new favorite GPR antenna, the GD80, the one for a drone, to finally avoid all crevasses we have been struggling with for the past years and efficiently scan the vast amount of ice.

Slowly thawing glaciers

The phone rang in September 2015, it was a long-distance call from a friend in Nepal. She was working in Kathmandu with research regarding climate change and glaciers and needed to investigate a smaller glacier at 5800-6000 m.a.sl. in the west Himalaya region. Research on the glacier had been ongoing for several years, but only on topography and movement of the ice. Now information was needed on the actual volume of the ice. To see how much it decreased in volume, cubic meters of ice is water, and not just in elevations or length. So, the aim for the expeditions was to map the bottom of the glacier. Which is most suitable to do with a low frequency GPR antenna. Again, I said yes, without blinking. And then realized I am afraid of heights… But off I went, reached 5200 m.a.sl., got height-sick, instructed our local mountaineer guide in GPR investigations between my periods of feeling really sick, and climbed down again.

During the days at the mountain, we hiked in moon-like surroundings, encountered yaks in the middle of the night, breathed deep, walked slow and had amazing views of the Himalaya peaks Annapurna and Dhaulagiri. It was a nervous wait for me, down in the valley again, but when the expeditions returned plenty of GPR data had been stored and could be analyzed for both the bottom topography of the glacier as well as for understanding the different parts of cold and warm ice. All to get a better picture of how the climate change affects our ice and snow deposits.

Snow and Ice fun

Investigations with GPR takes part all around the year, regardless of if you are trying to stay alive on an ice cap or lost in a snow drift on your backyard. So, snow and ice encounters are inevitable, and you may need to:

• Use snowshoes and a low frequency GPR antenna to measure the depth to bedrock in a very snowy steep slope at a ski-resort. During your sport holiday.
• Train the car testing industry to used high frequency GPR for lake ice thickness. Measurements can be made by foot, snowmobile, or old car wreck. The ice needs to be safe before expensive cars are allowed, of course.
• Instruct your colleagues to pull the low frequency GPR antenna behind a snowmobile to map super huge areas of peat. This was done to estimate the volume of peat, or in other words, the amount of renewable energy available.
• Misunderstand ground frost for nice soil layers in roads. It can be really difficult to see the difference.
• Measure the lake bottom topography and bottom conditions from the top of the lake ice. Sometimes you need to check these out, for instance prior construction of a sub-merged gas pipe. But be aware of double-ices, these ruins any GPR investigation efficiently.
• Construct home made snow chains to my measuring wheel. A wheel on ice or firm snow can really mess up your length measurements. PS. Today we have ready ones, with studs.
• Dig out your GX system from underneath snow cover, gathered both from snow fall and snow splash. I am glad the systems are water proof.
• Think, very often, if a big, shielded antenna could be used as a sledge for the downhill parts of your investigation lines. I think it would work perfect.

Some final words

Ice and snow are beautiful. And needed. For both the climate and for the adventure. So, let´s continue to work together to find environmentally friendly solutions for us and our planet Earth´s future development!

Jaana Gustafsson, Applications Specialist, Phd