This blog has been quiet for two years- hard to believe how fast the time went by. We'll try to post more frequently, especially now that the field season is underway.
We opened the camp on May 18 and found the tents and equipment in generally good shape. Conditions were already looking unusually warm based on weather from other stations in the area, and a pilot mentioned that he saw little snow on Melville Island while flying over in March.
When we arrived, there seemed to be a lot of snow, especially around camp where we had to dig it out. However, when we did our snow survey, we found it was quite the opposite. Snow is a funny thing, you just can't measure it in one spot. It blows around all winter and the depth tends to be quite different from place to place. Each year we carry out a snow survey that involves 28 locations in the river basins and at each location, we measure depth in ten spots along a line. We also collect snow samples with a metal tube and weigh the snow to determine how much water there actually is in the snow. This gives us a way to calculate what hydrologists call the "snow water equivalence", or SWE (s-whee). One way to think of SWE is how much water would be left on the land if you melted all of the snow. It is measured as a depth, so you can think of the depth of water for a given SWE.
The snow at CBAWO this year was very limited, the least we have measured since 2005. It was 49 mm, about 60% of a typical year. In many places, the snow was just a thin covering over the soil. That indicates that there is very little water on the land for runoff this spring, something that is very important for many of the systems we monitor.
One of the things that we were interested in sampling this year was the frozen soil to see how much water was in it and how ice was formed the previous winter. This affects how the soil thaws and how the water will flow in the soil. Many researchers recover samples of the deeper permafrost, but this soil is not really permafrost, as it almost always thaws. We refer to this as the "active layer", or the part of the soil that thaws during the summer. As the name implies, this is the part of the soil where a lot of important things happen: plants root, water moves and changes properties, and an important ecosystem of microbial life recycles dead plant matter and supports vegetation growth.
To sample the frozen soil, we use a power auger and a hollow bit that cuts down and brings up frozen soil material. The auger is big, powerful, and has a mind of it's own: when it hits a rock, it can stop dead and throw the people operating it. We give it a lot a respect and have affectionately named it 'Taz', after the Tasmanian Devil in the cartoons!
The frozen soil is pretty neat to look at. This photo shows a section from 60-75 cm depth, and you can see some clear ice lenses and structure starting to appear. Ice formed in these lenses late in the autumn and will only thaw late this coming summer. When it does, the water released will be able to drain out, but we find the quality of this water is very different from snow runoff. As you go deeper, there is even more ice, sometimes just ice for intervals of 10 cm or more.
These samples will be analysed for their water content and we plan to get images of the ice structure while they are frozen using a special scanner like the ones they use in hospitals to image bones. We hope by understanding how water is stored and moves through the soil at different times of year, we can better predict how climate changes will affect water in the High Arctic, and how this will contribute to the stability of the landscape and ecosystem.
And now to tease with an image that looks like something out of a movie. No, it is not some futuristic weapon. We actually put that underwater in the lakes to learn more about what is going on at the bottom. That is a story for another time. Thanks for following.
