Going Glacial! All set for Finse.

Hello, Adam here, and thanks for checking out our field blog!

Actually – ‘field blog’ is a little bit premature at the moment as I’m still sat in my flat in London…!  But my flight to Norway is early tomorrow morning, and I thought I’d just take the opportunity to outline the INTERACT-funded work we’re going to be doing at Finse Station over the next few weeks.

Finse Station is close to the glacier Midtdalsbreen (see the satellite photo below – thanks Google Earth!).   Midtdalsbreen flows in a north-easterly direction from the Hardangerjokulen ice cap, and we’ll be working on Midtdalsbreen while based at Finse.

Location of Finse and Midtdalsbreen in Norway.
Location of Finse and Midtdalsbreen in Norway.

What is so interesting about Midtdalsbreen?  I suppose that this is really a question for my colleague, Benny Reinardy, to answer – however, I will try to give you as good an overview as I can!  Benny is a glacial sedimentologist, and his trained eye has spotted something interesting in the landforms immediately in front of Midtdlasbreen.  These landforms are created as a glacier scrapes over the ground surface and, to a sedimentologist like Benny, they can serve as a record of what that glacier was like.  Benny believes that the landforms infront of Midtdalsbreen were created by a glacier that was frozen to its bed; however, the majority of Midtdalsbreen is unfrozen at its bed so, if Benny is right, the edges of the glacier must have a different thermal regime to the rest of it.  Our work at Finse is therefore to establish whether the marginal ice at Midtdalsbreen has liquid water at depth.  At some point during the fieldwork, I will ask Benny to contribute a blog to this page and he can give more detail.

However, when it comes to detecting liquid water within a glacier, I’m personally on more familiar territory!   I’m a geophysicist, and I specialise in the use of seismic and ground-penetrating radar (GPR) methods for characterising a target subsurface; and it’s GPR which we are using at Midtdalsbreen.  You can think of GPR as being like an x-ray for the ice; a transmitting antenna sends a pulse of radio wave energy into the glacier and, when that energy encounters some interface, it is reflected back to the ice surface and recorded at a receiving antenna.  That interface could be the glacier bed, rocky debris within the ice, or it could be pockets of englacial water.  The image below shows inclusions of englacial water within a glacier on Svalbard (at a depth of about 50-90 m beneath the glacier surface), in the high Norwegian Arctic.  Compared to the glacier bed, which gives a sharp radar response, englacial water is associated with a ‘fuzzy’ signal – if we see no such responses around the edges of Midtdalsbreen, this might indicate that the glacier is indeed frozen at its bed.

Englacial water2
GPR data from a glacier in Svalbard. Englacial water is interpreted from the ‘fuzzy region’ of GPR responses.

So – that’s the big idea!  We’ll give you some updates from Finse itself and let you know how we’re getting on.  I should also add that, while the Google Earth image suggests that Finse might be quite a green place, the image below is a shot the Finse webcam a couple of days ago.  However, the more snow, the better as far as I’m concerned – I did too many surveys last year in hot places, and it’s time to chill out again!

A still from the Finse webcam, taken on 15th April 2014.   Brrrr!
A still from the Finse webcam, taken on 15th April 2014. Brrrr!

Thanks for visiting – speak to you soon!

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