Trace gases

Trace gases in the stratosphere

Trace gases in the stratosphere - destruction of stratospheric ozone by halogenated hydrocarbons (CFC, HCFC etc.) - their vertical distribution measured using cryogenic sampling (balloon borne "cryosampler") and subsequent gaschromatographic analysis

	Science objectives
	Publications by MPS members

Science objectives

In 1974 Molina and Rowland alarmed the world with their hypothesis, continuous emissions of halogenated hydrocarbons to be responsible for a reduction of stratospheric ozone. This hypothesis and a tremendous need for experimental data initialised this project in 1976. The main task was the measurement of vertical distributions of all relevant trace gases, achieved by using cryogenic sampling ("cryosampler") with subsequent gaschromaotographic analyses.
Since then 25 balloon flights have been carried out at midlatitudes (Gap and Aire sur l'Adour, France), in the tropics (Hyderabad, India) and in the arctic (Kiruna, Sweden). So far the last two flights took place in France and India in 1999. Analytical methods were improved continuously. Today the most versatile instrument is a Varian SATURN GC/MS system with ion trap detector, besides other systems with different conventional detectors. The data base - soon available on this page - includes all species of importance in stratospheric ozone chemistry.

Other activities today: investigations on volcanogenic gases and glacier ice samples.