The Arctic Part 2: What the heck is a flux tower?

Our research in the arctic is primarily concerned with measuring carbon dioxide movement from the soil to the atmosphere (or atmosphere to soil), known as net ecosystem exchange. To do this we use instruments that measure carbon dioxide concentration, wind speed, solar radiation, and a bunch of other weather information. All of these sensors are attached to a tower in the field which we call flux towers. Also attached is a datalogger, which is basically a computer that stores all of the information the sensors collect.

As explained in a previous post, Adrian’s main interest is how wildfires change the landscape including biotic and abiotic (living and nonliving) features and how these changes affect the ecosystem’s ability to store carbon (this of course has climate change implications). In 2007, the largest arctic wildifire in known history occurred about 30 miles away from Toolik along the Anaktuvuk river. Adrian immediatly took advantage of this “natural experiment” by setting up three flux towers at the site. He’s been measuring CO2 flux there for the past five years to amass a long term data set that will hopefully allow us to see trends that could not be seen over short time periods.

A few days after getting to Toolik, we visited the field sites by helicopter to get the infrastructure for these towers built. The snow here was deeper than at the station. The helicopter had to force it’s nose down into the snow to prevent the tail from hitting the ground. Our pilot was able to get us about fifty feet from the towers, forcing us to plow a path the rest of the way. Walking in the snow is very precarious and awkward and is even harder when you are carrying equipment. I was immediatly given a shovel and put to work digging up the equipment that had been left over the winter. I didn’t mind this because it allowed me to warm up and get some excercise. Additionally, some of the sensors needed to be calibrated and they were collected to bring back to lab. The whole setup is powered by solar panels that charge car batteries. An additional set of solar panels were installed and the batteries replaced. We were lucky to get some great weather for doing our work and everything was set up in a pretty reasonable amount of time.

In addition to the Anaktuvuk fire, Adrian has been taking flux measurements at several other burn sites of various ages. This year he chose to go to a fire from 1977 which was about 25 miles from the arctic village of Point Lay (I will talk more about this town in the future). Here we had to set up two flux towers and solar panels from scratch which took considerably logner. But once again, the weather was in our favor and all of the work got done. Through all of this work, I gained a pretty good understanding of how the towers work (what all of the sensors do, how the power is supplied, etc.)

So while I will be working on many different projects in my time in the arctic, these flux towers are the heart of it all. They are the main reason I’m here. I will be flying out to them about every two weeks to switch out the memory cards (which have all of the collected data stored on it) , check that the instruments are working properly, and take some other measurements that need to be done by hand. By the end of the season I expect to be a flux tower wiz.

One of the amazing things about modern science is that more and more of it is becoming automated (see previous post), and more and more data sets are becoming freely available to the public through the internet. The arctic observatory network (AON) is a project that has several flux towers set up not far from here and their data is freely available for anyone to use, although it is a bit technial. Another cool site with free atmospheric CO2 data that is easier to understand if you are not a scientist is co2now.org. Check them out, look at some of their data, and maybe even use it to answer some questions or test some hypotheses of your own!

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