Seminar Ozean, Eis, Atmosphäre

Termin: 16.04.2002

Referent/in:

T. Blumenstock, Institut für Meteorologie und Klimaforschung, Universität Karlsruhe und Forschungszentrum Karlsruhe

Title: Measurements of trace gases with ground-based FTIR Spectroscopy in Kiruna and on Tenerife Island

Two ground-based FTIR (Fourier Transform Infrared) spectrometers are operated in the framework of the NDSC (Network for the Detection of Stratospheric Change), one in Kiruna (S) and the other one at Izaa Observatory on Tenerife Island (E). While on Tenerife Island data have been recorded since the beginning of 1999, measurements at Kiruna have been performed on a campaign basis since winter 1989/90. Since March 1996 a FTIR spectrometer is operated on a routine basis in collaboration with the IRF Kiruna and the University Nagoya (J). These observations are made to study stratospheric processes in the Arctic and the Sub-tropics.

From individual absorption lines column abundances of several trace gases like O3, H2O, N2O, CH4, HF, HCl, ClONO2, NO, NO2, and HNO3 can be derived. Furthermore, using the line shape of pressure depending absorption lines useful height information can be retrieved for some species like O3, N2O, CH4, HF, HCl, NO and HNO3. This method will be described together with time series of profiles. These profiles will be compared with those from ground-based Millimeterwave Radiometer (MIRA) and with model results calculated with the 3-D CTM KASIMA (Karlsruhe Simulation Model of the Middle Atmosphere).

The focus will be on results of the SOLVE-THESEO-2000-campaign which took place in Kiruna during winter 1999/2000. These results will be discussed in respect to chlorine activation and ozone loss as observed during winter 1999/2000 and compared with results from earlier winters.

In winter 1999/2000 PSCs (Polar Stratospheric Clouds) have been observed with ground-based FTIR. It will be shown which aerosol parameter can be retrieved from broadband, calibrated spectra.