First data set of H2O/HDO columns from the Tropospheric Monitoring Instrument (TROPOMI)

Schneider, Andreas; Borsdorff, Tobias; Brugh, Joost aan de; Aemisegger, Franziska; Feist, Dietrich G.; Kivi, Rigel; Hase, Frank; Schneider, Matthias und Landgraf, Jochen (2020): First data set of H2O/HDO columns from the Tropospheric Monitoring Instrument (TROPOMI). In: Atmospheric Measurement Techniques, Bd. 13, Nr. 1: S. 85-100

Abstract

Global measurements of atmospheric water vapour isotopologues aid to better understand the hydrological cycle and improve global circulation models. This paper presents a new data set of vertical column densities of H2O and HDO retrieved from short-wave infrared (2.3 mu m) reflectance measurements by the Tropospheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite. TROPOMI features daily global coverage with a spatial resolution of up to 7km x 7km. The retrieval utilises a profile-scaling approach. The forward model neglects scattering, and strict cloud filtering is therefore necessary. For validation, recent ground-based water vapour isotopologue measurements by the Total Carbon Column Observing Network (TCCON) are employed. A comparison of TCCON delta D with ground-based measurements by the Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) project for data prior to 2014 (where MUSICA data are available) shows a bias in TCCON delta D estimates. As TCCON HDO is currently not validated, an overall correction of recent TCCON HDO data is derived based on this finding. The agreement between the corrected TCCON measurements and co-located TROPOMI observations is good with an average bias of (-0.2 +/- 3) x 10(21) molec cm(-2) ((1.1 +/- 7.2) %) in H2O and (-2 +/- 7) x 10(17) molec cm(-2) ((-1.1 +/- 7.3) %) in HDO, which corresponds to a mean bias of (-14 +/- 17) parts per thousand) in a posteriori delta D. The bias is lower at low- and mid-latitude stations and higher at high-latitude stations. The use of the data set is demonstrated with a case study of a blocking anticyclone in northwestern Europe in July 2018 using single-overpass data.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1867-1381
• Sprache: Englisch