In the night from Friday to Saturday, a frontal system passed Inuvik. After it went trough a wide field of low level clouds remained above the Beaufort Sea. The clouds were forecasted to become thinner and disappear during the course of the day. That's why the flight was scheduled early with take-off at 10 am local. The target area for the cloud sampling was chosen straight north of Inuvik up to 71° North.At the airport fog again delayed the departure about 15 minutes.
Soon north of Inuvik low level clouds showed up. A cloud top altitude of 900 m above ground was observed by AMALi, the backscatter lidar on Polar 5. Only a few miles later, a second cloud layer with tops of about 1200 m overlayed the lower clouds. These clouds remained with no visible variability until end of the leg. So we decided to release only one drop sonde which confirmed the two layer structure of the low clouds. Temperatures were quite warm with a cloud top temperature of about -3° C while in flight level -5° C were measured. During the entire leg high cirrus clouds were observed by eye and by the radiation sensors. For Polar 6 penetrating the cloud was easy, as only liquid droplets were found and no icing occurred. 
On the way back to the shore line the clouds did not change. Observations of glories indicate pure liquid water clouds. Sometimes large glories related to small particles and narrow size distributions were seen. The transition of the two layer cloud to a single layer cloud was again detected by the lidar. Surprisingly in the altitudes between both tops of the layers an aerosol signal was measured by AMALi. This single layer cloud remained during the overpass of Tuk. While Polar 5 did fly only once above Tuk, Polar 6 measured at different altitudes to connect the airborne aerosol measurements with the ground station in Tuk. On the lowest level, the people in the ground station could easily see Polar 6 what was a big success for this flight.
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