Today was a beautiful day on the North Slope! Low clouds formed over Oliktok Point, replacing the clear weather we’d seen yesterday. This set up a very interesting scene, with the clouds supported by an air layer that was not the same one as was being observed at the surface. A perfect reason to deploy some unmanned aircraft and a tethered balloon to see what’s going on up there! We didn’t waste the opportunity, and sampled the atmosphere from sun up until well after sunset. It was a very long day, so for the time being I’ll let the photos do the talking!
![The tethered balloon getting ready for flight, as seen from a morning DataHawk flight.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMAG0671-1024x682.jpg)
The tethered balloon getting ready for flight, as seen from a morning DataHawk flight.
![Dancing among the clouds -- A DataHawk samples the cloud base environment over Oliktok Point.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMAG0361-1024x682.jpg)
Dancing among the clouds — A DataHawk samples the cloud base environment high over Oliktok Point.
![Temperature profiles from today's flights, showing the evolution of the surface and cloud-driven layers.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/profiles.jpg)
Temperature profiles from today’s flights, showing the evolution of the surface and cloud-driven layers.
![The newly forming sea ice, as seen from 20 meters above during a DataHawk flight.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMAG1224-1024x682.jpg)
The newly forming sea ice, as seen from 20 meters altitude during a DataHawk flight this afternoon.
![The tethered balloon during a good snow squall.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMG_3683-1024x768.jpg)
The tethered balloon during a good snow squall. It looks as though Carl’s VIPS instrument was able to sample some significant snowfall today.
![Eric, part of the tethered balloon crew, bringing the POPS and VIPS instruments back in after a long day of sampling.](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMG_3690-768x1024.jpg)
Eric, a member of the tethered balloon crew, bringing the POPS (top) and VIPS (bottom) instruments back in after a long day of sampling.
![Al, Carl and Matt working to get the last few meters of tether in at the end of the day. All smiles!](http://ciresblogs.colorado.edu/alaska-unmanned-3/wp-content/uploads/sites/56/2016/10/IMG_3697-1024x768.jpg)
Al, Carl and Matt working to get the last few meters of tether in at the end of the day. All smiles — thanks to everyone for helping to get some great measurements today!