Tuesday, January 1, 2013

Other fancy equipment

Aside from our measurements and samples that we take in the field, we have a few other pieces of equipment we use in the field to learn about the water tracks.

Soil temperature is being measured continuously in the water tracks. Soil temperature, of course, influences the melting of the water that creates the water tracks. To measure soil temperature, sensors are buried in the soil. They are attached to a data logger above ground, which records the temperature on a regular basis all year. A solar panel provides enough power to keep it running most of the year. Each year, we have to stop by and download the data. Here is Joe downloading the data from one of those loggers and replacing it with a fresh logger.

We've also been mapping the topography of the water tracks. The shape of the land surface influences how the water flows, so it's important to record each bump and turn in the land. To map the topography, we use a process called LIDAR. There is a special laser that shoots out an infrared beam. That infrared beam bounces off the land surface back to the source, and the speed at which the beam is returned will be influenced by the shape of the land surface. (Just think: The beam hitting a hill will come back sooner than the beam hitting the land farther away below it.) This way you can create a model of the surface in a computer using millions and millions of data points! Using this modern technology, we can determine the shape of the surface down to the scale of centimeters, and we can see how water is flowing through the soil in Antarctica and providing nutrients to the delicate ecosystems that exist here.

One new piece of equipment that we're using this year is an induction sounder. It measures how salty the soil is as you walk along! It does this by using a metal coil (inside the orange thing Joe is carrying), which creates a magnetic field. (That's called "inducing" a magnetic field, which is why it's called an induction sounder.) That magnetic field shoots into the soil, which bounces back as an electric field. Saltier soil bounces the electric field back differently than less salty soil, which is why we're able to measure how salty the soil is as we walk. The reason for measuring soil salinity is because water tracks tend to be very salty. Even if we can't see the water track on the surface, we can find them based on how salty the soil is.

Today was my last official day of field work. Tomorrow, I head back to McMurdo Station to finish up my work, pack my gear, and get ready to head back to the U.S. A short, but productive, field season!

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