Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Airborne measurements of stratospheric constituents

Airborne measurements were made of some of the most critical stratospheric constituents during the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME). Two high sensitive sub-millimetre sensors working at 500 GHz and at 625/650 GHz using superconducting superconductor insulator superconductor (SIS) diode mixers have been developed and interfaced to the SUMAS back-end spectrometers. Twenty measurement flights over Northern Europe have been performed onboard the high-flying research aircraft FALCON based at Kiruna (Sweden) during the campaign. Many flights were co-ordinated with other instruments participating in SESAME. With these sensors rotational line spectra of stratospheric trace gases have been observed. From the pressure broadened lineshape, height profiles of the volume-mixing-ratio were obtained using appropriate inversion methods. The vertical resolution is 8-10 km and the horizontal resolution less than 50 km for chlorine monoxide, hydrogen chloride, nitrous oxide and ozone. The project has been completed successfully, giving the following major results. Measurements inside and outside the polar vortex indicated the impact of heterogeneous chemistry over the Arctic. Up to 2.0 parts ber billion (ppb) chlorine monoxide have been obtained at 20 km altitude. Comparison with global model calculations (SLIMCAT, REPROBUS) show good agreement. Many flights have been co-ordinated with other experiments on the ground, in balloons, aircraft and satellites. The submillimetre measurements were combined and compared with the results of these instruments. All results have been stored on the NILU data bank and are available for further research.

Reported by

Universität Bremen
28334 Bremen