DESCARTES is a lightweight instrument for the measurement
of long-lived trace gases. The instrument was originally developed by
dr Francois Danis at the University of Cambridge. It is designed to
fly piggyback on other payloads, with a low weight of about 16 kg and
no need for telemetry. The instrument collects samples by letting a
measured volume of air pass through a tube containing a Carboxen
adsorbent. With the current setup of the instrument and analysis
equipment, atmospheric CFC-11, CFC-113, CCl4 and
CH3CCl3 are adsorbed in measurable
quantities. At present the instrument performance is well known for
the measurement of CFC-11. Laboratory tests indicate that reliable
estimates of atmospheric levels of CFC-113, CCl4 and
CH3CCl3 can be made as well.
One copy of
DESCARTES is operated by the University
of Cambridge. Another copy is operated by the Swedish Institute of
Space Physics. This copy has participated in several campaigns with
flights from Kiruna and Andøya.
The Swedish DESCARTES team consists of:
Hans Nilsson, project leader 
Johan Arvelius, Ph D
student 
In addition we co-operate with Andrew Robinson, John Pyle and Neil
Harris at the University of Cambridge, Centre for Atmospheric Science
at the Department of
Chemistry. The Swedish team has participated two large
stratospheric ozone campaigns, the ILAS validation campaign and the THESEO campaign , as
well as the national Swedish SKERRIES balloon programme and the
EU funded SAMMOA
campaign. Currently all flights are reported to the THESEO
database. Publications related to the project can be found in the publication list.
Results from flights 2000 was presented at The Sixth European
Symposium on Stratospheric Ozone Sept 2002 on a poster called Measured tracer profiles from the polar
stratosphere covering all seasons 2000 [ps]. Flight profiles from all flights
are calculated and available from the THESEO database. The uncertainty
of the measurements are under investigation. At the moment there is a
student, Susanne Roslin is
working on a masters degree project investigating the adsorption
efficiency at low pressure connected to the DESCARTES project which is
thougt to be the largest error. As part of this a technical test
flight was performed 2002-11-25. In this flight the desorption
efficiency was tested and no measurements done.
A total of 7 succesful DESCARTES flights were made during the ILAS
validation campaign. In the first flight during the THESEO campaign
the instrument crashed in the Northern sea. The salt water caused
considerable damage and the instrument was not operative again until
fall 1998. Since then 27 flights have been made, in the THESEO,
SKERRIES, SOLVE and SAMMOA campaigns as well as technical flight
arranged by ESRANGE.
DESCARTES is a lightweight instrument for the measurement
of long-lived trace gases. The instrument was originally developed by
dr Francois Danis at the University of Cambridge. It is designed to
fly piggyback on other payloads, with a low weight of about 16 kg and
no need for telemetry. The instrument collects samples by letting a
measured volume of air pass through a tube containing a Carboxen
adsorbent. With the current setup of the instrument and analysis
equipment, atmospheric CFC-11, CFC-113, CCl4 and
CH3CCl3 are adsorbed in measurable
quantities. At present the instrument performance is well known for
the measurement of CFC-11. Laboratory tests indicate that reliable
estimates of atmospheric levels of CFC-113, CCl4 and
CH3CCl3 can be made as well.