A large surface high pressure system occupied the Beaufort Sea. Its center was east of SHEBA ship. A major low pressure system was in southern Alaska. Barrow and the Arctic Coast were under northeasterly winds between these two systems. Boundary layer stratus clouds covered most of the Arctic Coast. Some very thin cirrus appear over Barrow but not west of the city. North of the coast over the ice, no clouds could be seen on the satellite image. The boundary layer stratus were optically thin because they are very difficult to see on the visible satellite image. Ice patterns and the ice/water are easily seen through them. The boundary layer stratus appear vividly on the 3.7 micron image as dark clouds because they reflect some solar radiation and this is a negative image of the measured radiation.
The trajectories to SHEBA ship show the air from all levels coming from the vicinity of the ship. This occured because the high has been nearly stationary with light winds for several days. The lower level air appeared to come from just east of the ship while the 6 and 9 km air came from the Chukchi Sea area just west of the ship.
The trajectories to Wainright show the low level air, surface up to 1.0 km, coming from east in the Beaufort Sea just north of the Alaskan Coast. The 1.5 km trajectory follows the coast line east of Barrow before curving north into the Canadian Islands. The 3.0 km trajectory shows air coming from western Canada acrossed northern Alaska to the Wainright vicinity. The higher level air, 6.0 and 9.0 km appear to come from the Pacific Ocean north across Alaska.
