christina j williamson

The Most Famous Forest

 

The lake at Hyytiälä

In the atmospheric chemistry world, especially the aerosol world, there is one place that everyone has heard of. It’s a forest by small lake, near a tiny town in the middle of Finland, and it’s called Hyytiälä (I said everyone knows of it, I didn’t say they could pronounce it, but for reference it’s something like huu-tee-ah-la).

Professor Markku Kulmala (Director of Atmospheric Sciences Division, University of Helsinki) in his natural habitat at Hyytiälä

Hyytiälä is famous because the University of Helsinki has set up an extensive measurement station here (the station is SMEAR II, one in a chain of stations in Finland), and many scientific discoveries have been made here as a result. It’s one of the first places we ever saw aerosol nucleation (small particles being produced in the air from gases). It’s also something of an atmospheric chemistry boot-camp. Most PhD students in the world who work on aerosols and atmospheric chemistry go through at least one summer or winter school there, where they study the theory, latest developments and instrumentation of the field, as well as get experience using instruments or processing data. They also learn how to sauna properly, how to endure the very cold water of the lake for swimming, and provide a good supply of protein for the resident army of mosquitos.

A  measurement tower at Hyytiälä

I went through one of the summer schools during my doctoral studies, but when the opportunity came up to pay a quick visit at the end of a conference in Helsinki, I was happy to go back. We toured the instrumentation throughout the forest, measurements from the smallest clusters of molecules that can kick-off the aerosol nucleation, to using lasers to measure cloud properties, to trapping growing tree branches in sealed boxes to photosynthesis via gas fluxes, and much much more. They even have instrumentation up on a 35m high tower to measure how these things change with distance from the ground.

Measurements over the forest from a 35m high tower
Looking down from the measurement tower at ground level atmospheric sampling – instruments are housed in these containers as well as huts around the forest 

We also took the opportunity to use the wonderful sauna on the lake, complete with swimming off the doc. Right now is the most beautiful time of the year in Finland – it has been sunny and warm, wildflowers are in full bloom due to the late spring this year, and the days are super long. When we left the lakeside last night it was still light, with a pink-tinted sunset sky. It was midnight.

Sauna on the lake at Hyytiälä

Midnight over the lake at Hyytiälä