Spectroscopic Database for TROPOMI/Sentinel-5 Precursor – 2.3 µm Region Finalized

The ESA project „SEOM-Improved Atmospheric Spectroscopy Databases (IAS)“ will improve the spectroscopic database for retrieval of the data products CO, CH4, O3 and SO2 column amounts measured by the TROPOMI instrument (TROPOspheric Monitoring Instrument) aboard the Sentinel-5 Precursor. The project was launched in February 2014 with 3 years duration. The spectroscopy of CO, CH4 and O3 in the 2.3 µm region is covered in the first 2 years, while UV measurements of SO2 and UV/FIR/IR measurements of ozone will be carried out in the last year. User requirements for the spectroscopic database were obtained by retrieval simulations, indicating the need to take line mixing into account in case of CH4, to measure HDO in case of water and even to measure line broadening of CH4 lines by water vapor. A dedicated line model is used to represent the laboratory spectra since the Voigt routine was found to be not sufficient to obtain the needed accuracy. The measurements in the 2.3 µm region are finalized. The analysis is planned to be finalized by April 2016. The new spectroscopic data will be presented and discussed.