A NASA aircraft expedition from October 1991 to March 1992 was staged over a period of eight months from Moffett Field, California; Fairbanks, Alaska; Anchorage, Alaska; Stavanger, Norway; and Bangor, Maine. The mission used two aircraft to study the lower stratosphere: a high altitude ER-2 aircraft for in situ observations and a long range DC-8 for remote sensing observations.