I spend at least a month (and usually two) every year in the north of Norway and Sweden, making the observations that I then try and make sense of during the rest of the year.

In spite of what you might expect (and I expected the first time I went up there) the Arctic isn't an empty space covered in snow, with only a few seals for company. In the summer it gets quite warm - warm enough to walk around in shorts and t-shirt and even warm enough to sunbathe!

The snow never goes from the mountains though, and last summer I was able to have a snowball fight with two visiting friends on the mountain above Tromsø. On the other hand this is what it looked like in late March, pretty wintry!

What is strange about the arctic in the summer is the daylight - the Sun stays up for months on end, so it never gets dark (in the winter it never gets light). The Norwegians like to make the most of this, so they often stay up all night too. I've often seen people working in their gardens at 2 or 3 in the morning!

I usually go up to Tromsø in May, which is right at the end of the winter there - two years ago there was 2 metres of snow still lying at the start of May. By the end of May most of the snow has gone, the trees are in leaf and there are flowers in the forest. I never get used to how fast spring happens in the Arctic.. And by the middle of September the snow is coming back.

The site where I work is in a valley about 30 km from Tromsø, the main city of the north of Norway (there are about 70000 people in Tromsø, but the city is very spread out over lots of islands). There are farms strung up the road along the valley, but the radar site is on the opposite site of the valley, in the forest and close to a waterfall. It's rather a beautiful place.

The other place I do a lot of work is Kiruna (which the Lapps call Giron, and they should know as they have their parliament there) in Sweden, which is about 5-6 hours drive from Tromsø, either over the mountains to the south or round, following the river down through Finland. The picture above is of the mountain near Kiruna, from the top of which it is said you can see 9% of Sweden - on a clear day presumably!

Kiruna is an iron-mining town - quite a surprising place to find in the middle of the arctic! It's also Sweden's "space city", where they have their rocket launching site and all their satellite receiving stations - the Swedes call Kiruna their "future city" and sometimes, when you see it from a distance across the forests it really does look like that.

So far I've not been up to the really far north - to Spitzbergen - an island off the north of Norway (at about 80 degrees north - try and find it on a map!), but I'm hoping to spend some time there one summer. EISCAT have a new observatory up there and I want to start using it - and besides, I'd like to see a polar bear (but only from a distance!).