Messerschmidt, J; Geibel, MC; Blumenstock, T; Chen, H; Deutscher, NM; Engel, A; Feist, DG; Gerbig, C; Gisi, M; Hase, F; Katrynski, K; Kolle, O; Lavric, JV; Notholt, J; Palm, M; Ramonet, M; Rettinger, M; Schmidt, M; Sussmann, R; Toon, GC; Truong, F; Warneke, T; Wennberg, PO; Wunch, D; Xueref-Remy, I
The Total Carbon Column Observing Network (TCCON) is a
ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the
column abundances of CO2, CH4, N2O, CO and O-2 are measured. CO2 is constrained with a precision
better than 0.25% (1-sigma). To achieve a similarly high accuracy, calibration to World
Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft
calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO
standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with
retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show
that the FTS measurements are consistently biased 1.1%+/-0.2% low with respect to WMO standards,
in agreement with previous TCCON calibration campaigns. The standard a priori profile for the
TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using
aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO
standards, the highly precise TCCON CO2 measurements of total column concentrations provide a
suitable database for the calibration and validation of nadir-viewing satellites.