Science Flight #2 - April 30

On Wednesday a small but intense low pressure system moved north of the shore line fast from west to east. The severe weather with freezing rain did not allow an early flight. At about 9 am rain and shortly after that snowfall reached Inuvik. After the low pressure system crossed Inuvik, the conditions improved. As forecasted, at the rear side of the low pressure system in the cold air mass, low level clouds were situated. Mid-level and cirrus clouds were not predicted for the area north east of Inuvik which was the target of this flight. The flight strategy was not changed compared to flight #1. One straight leg between C1 and C2 was sampled in collocation by Polar 5 and Polar 6.

Chasing Polar 6

On the first leg we observed clouds with different cloud top altitudes. In the first quarter, cloud top was below 600 m. In parts, the clouds were thin enough to be penetrated by AMALi. Later, the cloud top altitude increased in steps. First up to about 750 m above ground then to 1000 m. Towards the end of the log close to and behind C2 multiple thin cloud layers were detected, some reaching altitudes above 2000 m. The varying cloud structure made it hard for Polar 6 to define the vertical steps for covering the clouds profile. However on the long leg tree complete staircase profiles were sampled. 

For P5 the first leg was extended for some miles to let P6 pass and get in front position for the leg back to C1. While P6 again penetrated the clouds and finally climbed up to 10,000 ft for a trace gas profile, from Polar 5 four drop sondes were released. Each intended to characterize one of the different cloud sequences identified before by Amali. The drop sondes also detected the multilayer clouds. Close to C1, the clouds intensified showing a homogeneus cloud field. To probe this cloud with sufficient data and to release a further dropsonde, the second leg was expended for 20 NM behind C1.

For details read here: http://www.uni-leipzig.de/~racepac/flights/flight_02.html