EASOE Campaign (1991 - 1992)
The European Arctic Stratospheric Ozone Experiment (EASOE) was a project carried out during five months between November 1991 and March 1992, to study processes in the Arctic leading to ozone destruction and their connection with the northern middle latitudes. The aim was to produce a campaign which was extensive in both time and space, covering the period from vortex spin-up to decay and making measurements over large parts of the northern hemisphere.
The effort -that relied heavily in the experience gained from previous campaigns like CHEOPS and TECHNOPS- involved near 250 scientists from 18 countries.
Twenty stations have been involved in ground based measurements of chemical composition at locations near the Arctic Circle and in northern Europe, three aircrafts flew 100 missions during the campaign to determine the distributions of a wide variety of trace species, and the ozone concentration was measured routinely at many locations using small balloons carrying lightweight ozone sensors, giving unprecedented coverage of the Arctic stratosphere in winter.
The wide spatial coverage provided by the ground-based and aircraft measurements was complemented by stratospheric balloon flights that measured the vertical profiles of stratospheric constituents. Those were launched by the balloon group of the Centre National de E'tudes Spatiales (CNES) from the Swedish base of ESRANGE, near Kiruna. Typical flights of several hours duration took the payloads to Finland. In addition, recovery from the Kola Peninsula (in the then Soviet Union) was negotiated and some flights took advantage of the longer flight duration provided.
43 balloon flights were performed during the campaign, transporting instruments like ELHYSA (Etude de L'Hygromérie Stratosphérique), SAOZ (Systeme d'Analyse par Observation Zenithale), MIPAS-B (Michelson Interferometer for Passive Atmospheric Sounding - Balloonborne) and RADIBAL (RADIomètre BALlon), to name a few.
The results obtained were perturbing, since they revealed that ozone quantities had never been so low in Northern Europe. This campaign would be continued by several others in the years to come like SESAME, and SOLVE-THESEO.
List of balloons launched during the EASOE campaign