Atmospheric Mission ODIN - Twelve Successful Years in Orbit Serving Atmospheric and Climate Science
Dannenberg, Kristine1; Frisk, Urban2; Lundin, Stefan3; Murtagh, Donal4; Silverlind, Stig-Ove5; von Schéele, Fredrik2
1Swedish National Space Board, SWEDEN; 2Omnisys Instruments, SWEDEN; 3OHB Sweden, SWEDEN; 4Chalmers, SWEDEN; 5SSC, SWEDEN

The Odin spacecraft, developed in Sweden in cooperation with partners in Canada, Finland and France was launched on a START-1 rocket from Svobodny in Russia on February 20, 2001, into a sun-synchronous circular orbit of 630 km altitude. More that ten years were required to develop and build the satellite, and its design life-time was assigned to be two years. In 2013 the satellite is still in orbit after twelve years of successful operations, carrying out atmospheric measurements and recording time-series of atmospheric species over a full solar circle. Esrange ground station, situated at a latitude of 68° in northern Sweden, is being used for the communications with the satellite during ten out of fifteen orbits per day.

Odin spacecraft carries two different instruments, a Sub-Milimeter Radiometer (SMR) and an Optical Spectrograph and Infra-Red Imaging System (OSIRIS). SMR measures profiles of many atmospheric species such as O3, CO, ClO and others. The OSIRIS instrument records vertical profiles of the scattered sunlight from the upper troposphere into the lower mesosphere and produces height profiles of O3, NO2 and stratospheric aerosols.

During the first six years of operations, the Odin satellite was operated as a joint mission sharing its observations between astronomy and aeronomy disciplines. In 2007 it was decided to focus on the aeronomy data as the astronomers were quite satisfied with the astronomy measurements and the results obtained. In addition, certain costs savings and optimisation of the operations had to be implemented in order to achieve affordable Odin operations during the extension of its life-time. The interest into the climate-relevant atmospheric data and time-series of various aeronomy parameters was large among the scientific community; therefore the decision to continue the Odin operations in the atmospheric mode was well motivated.

In 2007 the Odin satellite was approved as ESA Third Party Mission in order to serve even larger scientific community interested in atmospheric data and related climate research. Odin measurements, and the time-series of ozone in particular, are currently used in various science projects, including the Ozone_cci project within the ESA Climate Change Initiative, being a clear evidence of the high importance of the time-series obtained by the Odin instruments during the last decade. Since last year, the importance of the Odin data has increased further, being an important gap-filler after the loss of the Envisat satellite.

The current presentation will give an overview of the Odin spacecraft, its data and highlights from the scientific studies based on the Odin data and time-series in particular. It will also provide an overview of the data products available for atmospheric research.

We would like to acknowledge our colleagues at University of Saskatchewan, Saskatoon (Canada); CNRS, Service d'Aeronomie, Paris (France); CNRS, Laboratoire d'Aerologie, Toulouse (France); Finnish Meteorological Institute, Helsinki (Finland) and Department of Meteorology, Stockholm University, Stockholm (Sweden). We would also like to thank our partner agencies CNES, CSA, TEKES and ESA for their contribution to this highly successful mission.

Figure 1. Time-series of tropical mesospheric water vapour at 80 km altitude (-10 S to +10 N), measured by the Odin instrument SMR during 2002-2012 (courtesy of Joachim Urban, Chalmers, SWEDEN).