One of the larger instruments being connected to the auxiliary balloon

The Envisat Stratospheric Aircraft and Balloon Campaign (ESABC) continued last month in the north of Sweden where 4 balloon flights were successfully carried out. The objective of these balloon flights is to validate the data of Envisat’s 3 chemistry instruments at high latitudes.

The balloon flights are an important component of the larger ESABC campaign, which began in Italy in July and is set to continue for the next 12 months. The campaign as a whole is designed to check the results from the MIPAS, GOMOS and SCIAMACHY chemistry instruments on board Envisat. This is achieved by taking independent atmospheric measurements using airborne remote sensing and in-situ instruments as Envisat passes over the campaign launch area. The instruments on Envisat are then validated by confirming that the data from Envisat are consistent with the independent data taken during the campaigns. These validation campaigns play an important role in obtaining good vertical resolution measurements, far better than using data taken from the ground. Although such atmospheric campaigns are expensive to implement, the advantage of retrieving such high accuracy data and ease with which in-situ measurements can be interpreted justifies the cost. In order for the validation programme to be as complete as possible the ESABC campaign is to measure atmospheric constituents at different latitudes and during several seasons. The main purpose of the balloon flights launched from Kiruna in Sweden is to validate the chemistry instruments at high latitudes. Kiruna has been a major European site for atmospheric chemistry campaigns for more than 11 years and has played an important role in the observation of ozone depletion.

The lightest instruments (SOAZ) and the balloons minutes before the launch

The campaign was carried out in this remote part of Sweden over a 3-week period in August. Despite the constant plague of mosquitoes the scientists and operational staff had to endure throughout their stay there, it was hailed as a complete success. Each of the 4 balloon flights carried a different instrument configuration provided by scientific teams from France, Japan, Germany and Finland whilst the actual launches were carried out by CNES (Centre National d’Etudes Spatiales) using the Swedish Space Corporation (SSC) facilities at the ESRANGE launch pad near Kiruna. Just 5 kilometres from Kiruna is the Envisat Receiving Station, which receives data from Envisat when the satellite is over northern latitudes – the station was fully operational throughout the balloon campaign.