Airborne Multi AXis DOAS instrument and measurements of two-dimensional tropospheric trace gas distributions

The Airborne Multi AXis DOAS instrument was developed and successfully operated during four measurement campaigns. Depending on the purpose the instrument was installed on two different aeroplanes flying either close to the tropopause or in the mixing layer. In a detailed sensitivity study the possibilities of the measurements were investigated. For a qualitatively good observation of tropospheric trace gases (e.g. NO2 and HCHO) additional information about the mixing layer height and the aerosol extinction is essential. This information can be gained from either independent measurements or retrieved from the measurements themselves. For example based on the O4 observation from different lines of sight the aerosol extinction can be estimated. A very good agreement between tropospheric vertical NO2 columns for AMAXDOAS and SCIAMACHY measurements will be derived, if the AMF calculation is based on independent observation. The linear correlation between the datasets results in a slope of 1 ± 0.07. Due to the measurement system the AMAXDOAS instrument is ideal for flux estimations. For one flight just above the mixing layer the total HCHO production of Milano is estimated to 3.5*10^24 molec/s. In total the plume was 20 km wide. A detailed plume study in lee of a power plant was performed. Here the different NO2 slant column densities were used for the reconstruction of a 2-dimensional trace gas distribution. The estimated flux originating from the power plant equals 2.5*10^24 molec/s