by Liz Kalaugher
Sometimes research can be tough. To protect their new air temperature measurement kit from the sun, the Helsinki research group I’m following this week needed beer cans. Sixty-one of them. So the team has been diligently drinking with the sole purpose of providing test equipment.
Once the challenge was met, Jussi Mäkinen spray-painted the cans white to increase their reflectivity and transform them into white ventilated radiation shields, although he did point out that this removed any sponsorship opportunities. Stakes made from wooden fence posts got the same treatment, along with the addition of a looped cable-tie that will hold an iButton temperature logger.
Out in the field on Tuesday, on the southern slopes of Saana fell, Peter le Roux hammered in 2 or 3 fence posts near the outer edges of six of the team’s study grids, so that the top was 50 cm above the ground. He placed an iButton, which looks like a large watch battery, into the circle of the cable tie, and nailed a beer can “hat” into position. Finally, an extra coating of white paint was in order, just in case.
By reflecting back sunlight, the paint – and beer can – will prevent the temperature sensor inside the iButton from measuring how much the sun has warmed the equipment, rather than the air temperature. A height of half a metre isn’t standard for measuring air temperature but in these sites it’s enough to be comfortably above the vegetation while hopefully too low to attract much attention from reindeer, who are nosey and like to scratch themselves on posts. It’s possible that snow movement down the slope may push the posts over, making the temperature readings too close to the vegetation. The team should get at least some measurements, however, before heavy snow sets in.
The iButtons will measure temperature every four hours for almost a year; a researcher will retrieve the data by holding a reader against each one.
The measurements should help clear up whether the large variations in soil temperature the team has found at their test plots are due, as they suspect, to local conditions such as soil moisture, drainage, vegetation cover and which way the slope faces, or are down to unexpectedly large variations in air temperature.
Slope is the name of the game here. It’s pretty steep up on Saana’s southern face but the views are stunning – lakes and mountains in a 180° panorama. The road, one of only two in the 8,400 square-km province of Enontekiö, lies far below, and across Lake Kilpisjärvi we can see the point where Finland, Norway and Sweden meet. A few hundred metres above us as we eat our lunch is the rocky summit, where ravens and falcons nest. An airborne battle breaks out between a falcon, probably a peregrine, and a raven. The raven, although larger, is driven away.
On the way home, I realise that I no longer feel the need to take a picture of every reindeer I see.
- This trip was funded by a European Geosciences Union (EGU) Science Journalism Fellowship.