Expectations:
Takeoff: 0830 UT, 0930 LT
Duration: About 9 hours.
Comments:
The vortex has a lobe that extends equatorward over Scandinavia. Low temperatures occur just to the north of Norway and past Spitsbergen. Some wave activity is forecast for Scandinavia, south of Kiruna, and for Spitsbergen.
Goals:
Flight Report:
Take off was on time. Beautiful sunrise on climb out. We were above the local cloud deck at 20 kft, and a spectacular set of PSCs is visible over the sun. These clouds appear as long linear features oriented roughly north-south. Near waypoint 2, there is a PSC between about 20 and 23 km. According to LASE and DIAL the backscatter ratio is about 2, which is depolarizing strongly in the infrared and weakly in the visible. The MTP temperature at 20 km coincides with the NAT condensation line and is too warm for ice condensation. However, visually it appears that some of the clouds on the sunrise horizon are made of ice. There are also isolated ice clouds on the western horizon. NAT temperatures and PSCs are at altitudes as low as 17 km near the end of the sun run. At the very end of the sun run, PSCs either vanished or were very weak. We were projected to cross the NAT line near this point. DIAL ozone suggests that we were near the edge of the vortex as well. Shortly after the turn toward waypoint 5, near 62䓲´N, Hostetler's lidar reported a PSC near 20 km. Parts of this cloud do not appear to be depolarizing. From 65 to 66°N, a highly backscattering PSC (20) that was depolarizing was present. This is possibly a type 2.
The ER-2 did take off, so we have decided to fly the flight as planned. Near 67°N, ice PSCs of small size are clearly visible to the west of the aircraft. The PSCs observed by DIAL also clearly show waves. As we approach Kiruna, there is a PSC that should be within ER-2 altitude range at about 18.5 km. It is strongly depolarizing (25% in infrared, but may not be depolarizing in the visible), with a total scattering ratio of about 1.5. At Kiruna we see a very dense field of ice clouds just ahead of and to the front of the aircraft. There is a PSC with a bottom at 19 km. Just north of Kiruna there is a cloud from 16 to 18 km and another at 20 to 21 km. This cloud is only weakly depolarizing in the infrared (about 2%). It also has a strong wavelength dependence.
Between about 69°N and 71°N there seemed to be no PSC above the aircraft; however, they were clearly visible on the western horizon. At 72°N we encountered a thin cloud at 20 km. At 73°N there was a distinct layer between about 16 and 18 km altitude. It had infrared depolarization, but no clear visible depolarization. The backscatter ratio in the infrared was about 1.2. At 80°N we remained below a double PSC layer. One layer was located between 18 and 19 km and had only modest or no infrared depolarization. The other layer, from 15 to 18 km, was strongly depolarizing in the infrared. The lower layer has been present for at least one hour; however, the upper layer has been present for only about 20 min. The ER-2 dip should take them across both of the layers. There is also another layer from 20 to 21 km that appeared in the past 10 min. This general pattern persisted at 83°N, where the ER-2 began its dive. There appears to be a depolarizing layer below 18 km, then a more weakly or not depolarizing (in the infrared) layer or set of layers above 18 km. The upper layer is more strongly scattering in the visible, while the lower one is more strongly scattering in the infrared. All of this is consistent with the lower layer being dominated by larger solid particles and the upper one being dominated by smaller liquid particles. At 87°N the layer between 18 and 19 km faded. A strong layer was present from 20 to 22 km, and another layer between 15 and 18 km. Both of these clouds were depolarizing. The upper cloud also had relatively strong visible backscattering (1.1). After the turn near 89°N, the PSCs repeated themselves very closely for about 30 min. After that, a faint layer near 22 km was visible on the southward trip that was not evident on the northbound leg. At 67°N on the return, the PSCs suddenly vanished.