SHEBA ship was under a large uniform stratus cloud as evident in the satellite IR image. The satellite visible image shows that the cloud was optically thin enough for patterns in the ice to be seen through the cloud.
The ship radar shows that broken clouds up to 5 km altitude were over the ship in the morning but not after 22:00 UT when the C-130 reached the ship. After this time a uniform cloud up to 1 km appeared on the radar.
The lidar had the strongest returns near the cloud top, 1 km. However, the lidar did not seen the clouds above 1 km earlier in the day. This implies the lidar was blocked and cloud not see above the bright band. The maximum optical depth penetrable by the lidar is about 3.
The larger scale weather shows a strong surface low far north of the SHEBA ship ice camp. The higher clouds that appeared earlier on the radar apparently evaporated.
The trajectory analysis to SHEBA ship indicates that the low level air came from the west and traveled only a short distance. Upper level air came from near the pole rotating around the low that was north of the ship for a few days.
The trajectory analysis to Barrow shows the low level air, surface-1.0 km, came from the region near Barrow, while the 1.5 km air came from the south acrossed Alaska. Trajectories from 3-9 km indicate the air came from the arctic along the northern coast of Siberia.
