On our second day (August 23) in Trail valley Creek (TVC) my scientific dream came through: we are measuring on the ground, while the Polar5 aircraft is flying a grid above us with the extent of about 19 km x 13 km. That means we can directly compare our ground measurements with the airborne measurements. This is a rare case and from a scientific point of view pretty awesome!
Stephan operating the Global Network Satellite System survey station. Source: Julia Boike
The ice in the soil is disappearing
It took a while to make this happen. There was a very long stretch of bad weather, some trouble with the flight planning software, and one flight with bad weather over TVC with no data. But today it all works out. We are spread out on the tundra and survey climate, vegetation and soil while the Polar5 does aerial laser scanning and takes high resolution optical images. We also use a Global Network Satellite System (GNSS) survey station to measure our position with very high precision, that is with an accuracy better than 1 cm. These measurements will be necessary to check and validate the aerial laser scanning data from the Polar5. In 2016 we measured this grid already with the Polar5 taking airborne measurments simultaneously. Now we can compare the different years and see how the land surface changed during that time over the larger TVC area. We already had a quick look at the 2016 and 2018 data – it seems that the ground subsided a few centimetres meaning that the permafrost ice in the soil is dissapearing.
Julia digging soil pits, taking samples of the soil and installing soil sensors. Source: Stephan Lange
Mapping thermokarst with the drone. Source: Julia Boike
Workout on the tundra
Measuring this grid is hard work. Just walking on the tussock tundra, over and through dense shrubs, or crossing waterways, can be challenging and is a full workout. In addition, we have to move our equipment such as the climate stations to take measurements in our survey grid. We also take daily thaw depth measurements with a penetration probe. Because the clay soil is very dense this is a physical challenge as well!
Julia measuring thaw depth. Source: Stephan Lange
Walking through dense shrubs. Source: Inge Juszak
Edited by: Sina Muster
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