June 28, 2011: US
June 29, 2011: AU
The Southern Ocean was under solid cover during the flight from Christchurch, New Zealand to Hobart, Australia, on the island of Tasmania. However the GV was able to get low enough to sample the boundary layer on most dips. The boundary layer is a low level layer in the atmosphere that is directly influenced by its contact and interaction with the surface of the earth, both land and sea. It is an important atmospheric layer to sample as it is mixed very well, and it is the layer that directly influences life on Earth, while the layer above has more bands and streaks of various air samples. The boundary layer is, for the most part, where the majority of the weather that we see and experience exists.
Special precautions were taken to avoid the ash cloud that is circumnavigating the Southern Hemisphere, causing issues with flight traffic, mostly due to safety concerns for the aircraft. Many forecast models were consulted, and with a highly calculated and educated decision, the HIPPO team planned a conservative flight for their "Southern Polar Region" flight, going only as far south as about 46.5ºS, and then turning North to Hobart. They did not encounter any ash along the way and arrived happily in Tasmania.