Shipborne solar absorption measurements of CO2, CH4, N2O and CO and comparison with SCIAMACHY WFM-DOAS retrievals

[摘要] CO, CH₄, N₂O and CO₂ were retrieved from high resolutionsolar absorption spectra obtained during a ship cruise from Capetown toBremerhaven in January/February 2003 by Fourier Transform Infrared (FTIR)spectroscopy. Precisions of better than 0.5% for the column averagedvolume mixing ratios (VMR) of CH₄ and CO₂ are achieved using ofO₂ as a reference gas. Shipborne FTIR-measurements of CO and data fromSCIAMACHY/ENVISAT retrieved by the Weighting Function Modified DifferentialOptical Absorption Spectroscopy (WFM-DOAS) retrieval algorithm showqualitatively the same latitudinal variations. WFM-DOAS data of CH₄,N₂O and CO₂ measured over sea exhibit a great spread. The spreadis significantly reduced for satellite measurements over land and areasonable agreement can be obtained if the shipborne data are compared withthe closest SCIAMACHY measurements over land. The number of comparisons istoo small to draw conclusions. However, by including only WFM-DOAS data withsmall errors the shipborne and WFM-DOAS data compare within 5% forCH₄ and CO₂ and within 30% for N₂O.

[学科分类] 大气科学