Validation of five years (2003-2007) of SCIAMACHY CO total column measurements using ground-based spectrometer observations
journal contribution
posted on 2024-11-14, 16:22 authored by A T J de Laat, A M S Gloudemans, H Schrijver, I Aben, Y Nagahama, K Suzuki, E Mahieu, Nicholas JonesNicholas Jones, Helen MurphyHelen Murphy, Nicholas DeutscherNicholas Deutscher, David GriffithDavid Griffith, M De Maziere, R L Mittermeier, H Fast, J Notholt, M Palm, T Hawat, T Blumenstock, F Hase, M Schneider, C Rinsland, A V Dzhola, E I Grechko, A M Poberovskii, M V Makarova, J Mellqvist, A Strandberg, R Sussmann, T Borsdorff, M RettingerAbstract. This paper presents a validation study of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) carbon monoxide (CO) total column measurements from the Iterative Maximum Likelihood Method (IMLM) algorithm using ground-based spectrometer observations from twenty surface stations for the five year time period of 2003–2007. Overall we find a good agreement between SCIAMACHY and ground-based observations for both mean values as well as seasonal variations. For high-latitude Northern Hemisphere stations absolute differences between SCIAMACHY and ground-based measurements are close to or fall within the SCIAMACHY CO 2 precision of 0.2×1018 molecules/cm2 (10%) indicating that SCIAMACHY can observe CO accurately at high Northern Hemisphere latitudes. For Northern Hemisphere mid-latitude stations the validation is complicated due to the vicinity of emission sources for almost all stations, leading to higher ground-based measurements compared to SCIAMACHY CO within its typical sampling area of 8 ×8. Comparisons with Northern Hemisphere mountain stations are hampered by elevation effects. After accounting for these effects, the validation provides satisfactory results