Abstract. An airfreight container with automated
Abstract. A large airfreight container with automated instruments for measurement of atmospheric gases and trace compounds was operated on a monthly basis onboard a Boeing 767-300 ER of LTU International Airways during long-distance flights from 1997 to 2002 (CARIBIC, Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container, http://www.caribic-atmospheric.com). Subsequently a more advanced system has been developed, using a larger capacity container with additional equipment and an improved inlet system. CARIBIC phase #2 was implemented on a new long-range aircraft type Airbus A340-600 of the Lufthansa German Airlines (Star Alliance) in December 2004, creating a powerful flying observatory. The instrument package comprises detectors for the measurement of O3, total and gaseous H2O, NO and NOy, CO, CO2, O2, Hg, and number concentrations of sub-micrometer particles (>4 nm, >12 nm, and >18 nm diameter). Furthermore, an optical particle counter and a proton transfer mass spectrometer (PTR-MS) are installed. Aerosol samples are collected for analyses of elemental composition and particle morphology after flight. Air samples are taken in glass containers for laboratory analyses of hydrocarbons, halocarbons and greenhouse gases in several laboratories. Absorption tubes collect oxygenated volatile organic compounds. Three differential optical absorption spectrometers (DOAS) with their telescopes mounted in the inlet system measure atmospheric trace gases such as BrO, HONO, and NO2. A video camera mounted in the inlet provides information about clouds along the flight track. Here we describe the flying observatory and report examples of measurement results.
Abstract. Atmospheric airborne measurements of CO 2 are very well suited for estimating the time-varying distribution of carbon sources and sinks at the regional scale due to the large geographical area covered over a short time. We present here an analysis of two cross-European airborne campaigns carried out on 23-26 May 2001 (CAATER-1) and 2-3 October 2002 (CAATER-2) over Western Europe. The area covered during CAATER-1 and CAATER-2 was 4 • W to 14 • E long; 44 • N to 52 • N lat and 1 • E to 17 • E long; 46 • N to 52 • N lat respectively. High precision in situ CO 2 , CO and Radon 222 measurements were recorded. Flask samples were collected during both campaigns to cross-validate the in situ data. During CAATER-1 and CAATER-2, the mean CO 2 concentration was 370.1 ± 4.0 (1-σ standard deviation) ppm and 371.7 ± 5.0 (1-σ ) ppm respectively. A HYS-PLIT back-trajectories analysis shows that during CAATER 1, northwesterly winds prevailed. In the planetary boundary layer (PBL) air masses became contaminated over Benelux and Western Germany by emissions from these highly urbanized areas, reaching about 380 ppm. Air masses passing over rural areas were depleted in CO 2 because of the photosynthesis activity of the vegetation, with observations as low as 355 ppm. During CAATER-2, the back-trajectory analysis showed that air masses were distributed among the 4 sectors. Air masses were enriched in CO 2 and CO over anthropogenic emission spots in Germany but also in Poland, as these countries have part of the most CO 2 -emitting coal-based plants Correspondence to: I. Xueref-Remy (irene.xueref@lsce.ipsl.fr) in Europe. Simultaneous measurements of in situ CO 2 and CO combined with back-trajectories helped us to distinguish between fossil fuel emissions and other CO 2 sources. The CO/ CO 2 ratios (R 2 = 0.33 to 0.88, slopes = 2.42 to 10.37), calculated for anthropogenic-influenced air masses over different countries/regions matched national inventories quite well, showing that airborne measurements can help to identify the origin of fossil fuel emissions in the PBL even when distanced by several days/hundreds of kms from their sources. We have compared airborne CO 2 observations to nearby ground station measurements and thereby, confirmed that measurements taken in the lower few meters of the PBL (low-level ground stations) are representative of the local scale, while those located in the free troposphere (FT) (moutain stations) are representative of atmospheric CO 2 regionally on a scale of a few hundred kilometers. Stations located several 100 km away from each other differ from a few ppm in their measurements indicating the existence of a gradient within the free troposphere. Observations at stations located on top of small mountains may match the airborne data if the sampled air comes from the FT rather than coming up from the valley. Finally, the analysis of the CO 2 vertical variability conducted on the 14 profiles recorded in each campaign shows a variability at least 5 to 8 times higher in the PBL (the 1-σ standard ...
CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) resumed regular measurement flights with an extended scientific payload in December 2004. After an automated measurement container was successfully deployed on intercontinental flights using a Boeing 767 from 1997 to 2002, a far more powerful package now is deployed using a new Airbus A340‐600 made available by Lufthansa German Airlines (Star Alliance). The new CARIBIC system will help address a range of current atmospheric science questions during its projected lifetime of 10 years. European and Japanese scientists are developing a variety of atmospheric chemistry research and monitoring projects based on the use of passenger aircraft. This is a logical approach with a main advantage being that near‐global coverage is obtained, in contrast to limited coverage through research aircraftbased expeditions. Moreover, highly detailed and consistent data sets can be acquired, as compared to satellite observations in general. In addition, even compared to land‐based observatories, operational costs are moderate.
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