CARIBIC - The flying observing system
A Lufthansa passenger aircraft carries the CARIBIC container
to various destinations
to perform monthly measurements on long-distance flights.
The project CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) deploys a measurement container onboard a Lufthansa passenger aircraft (Airbus A340-600), see a picture of the inlet. The container accommodates 15 fully automated instruments for measurements of aerosols and various trace gases. In addition to in-situ measurements, whole air samples are collected in glass flasks during the CARIBIC flights at roughly one hour intervals with sampling times between 30 and 120 seconds. The samples are analysed for greenhouse gases as well as for organic compounds and isotopes by a number of European laboratories.
The container became operational in December 2004, with flights conducted almost monthly out of Frankfurt, Germany, to various destinations in South America, Asia, and North America (see map below). At cruising altitudes between 9 and 13 km the aircraft frequently crosses the tropopause, in the extra-tropics about 40% of the flight time is spent in the transition layer above the tropopause (ex-TTL).
The panel below shows CO2 from flask analysis of CARIBIC whole air samples taken on flights to Asia from 2005 to 2008 in comparison with measurements from ground stations situated close to the aircraft flight tracks (see map).
The annual cycle of CO2 with the summer minimum due to by the carbon fixation by the vegetation is clearly visible in all curves. The CARIBIC data show very good agreement with the ground-based observations. The comparison shows the expected damping of the seasonal cycle's amplitude with increasing altitude of the location. In winter, when the CO2 mixing ratio reaches its maximum, the CARIBIC tropospheric data matches the CO2 level of the highest of the selected stations, Hanle in northern India (HLE). In summer, the minimum mixing ratios are lower at the mountain station than the CARIBIC data. This reflects the influence of the local vegetation.
See the News Archive for previous news from the GEOmon project.
