An empirical study on the importance of a speed-dependent Voigt line shape model for tropospheric water vapor profile remote sensing

Tropospheric water vapour isotopologue data (H<sub>2</sub><sup>16</sup>O, H<sub>2</sub><sup>18</sup>O, and HD<sup>16</sup>O) as obtained from NDACC/FTIR solar absorption spectra

“…For further optimisation of the HI-TRAN parameters, we used high-quality H 2 O and δD aircraft in situ profile references, coincident FTIR spectra, and FTIR spectra measured at three rather distinct sites (Izaña on Tenerife, subtropical ocean; Karlsruhe, central Europe; and Kiruna, northern Sweden). This method for line parameter optimisation by means of atmospheric spectra is described in detail in Hase (2009) andSchneider et al (2011). We changed line intensities and broadening parameters by about 5-10 %, which is in agreement with the uncertainty values as given in the HITRAN parameter files.…”

“…For both versions, the water vapour isotopologues parameters have been adjusted for the speed-dependent Voigt line shape (Schneider et al, 2011). For further optimisation of the HI-TRAN parameters, we used high-quality H 2 O and δD aircraft in situ profile references, coincident FTIR spectra, and FTIR spectra measured at three rather distinct sites (Izaña on Tenerife, subtropical ocean; Karlsruhe, central Europe; and Kiruna, northern Sweden).…”

“…D 'Eu et al, 2002;Schneider et al, 2011) and fit line intensity (S) and pressure broadening (γ air ). We use six high-quality H 2 O and δD in situ profiles measured during an aircraft campaign in the surroundings of Tenerife and in coincidence with ground-based FTIR observations Schneider et al, 2015) for empirically estimating the overall errors in S and γ air .…”

The MUSICA MetOp/IASI H<sub>2</sub>O and δD products: characterisation and long-term comparison to NDACC/FTIR data

“…2 of Schneider et al, 2012) as well as four spectral auxiliary microwindows containing CO 2 lines (in order to optimally estimate the temperature from the measured spectra; Schneider and Hase, 2008). We use HITRAN 2008 (High-Resolution Transmission Molecular Absorption Database) spectroscopic parameters (Rothman et al, 2009(Rothman et al, , with 2009, while for the water vapour isotopologues we use parameters that have been adjusted for the speeddependent Voigt line shape (Schneider et al, 2011b O, O 3 , N 2 O, CH 4 , HCl, and C 2 H 6 . For the constraint of the water vapour isotopologue state we construct a priori covariances for humidity and δD (S aH and S aI , respectively; see Eq.…”

MIPAS-STR measurements in the Arctic UTLS in winter/spring 2010: instrument characterization, retrieval and validation

“…Virtually continuum-like contributions might also result from imperfect spectral modelling of adjacent spectral signatures, using the Voigt model, since it does not always allow for a sufficient reconstruction of the observed spectral line shapes (e.g. Ciurylo, 1998;Boone et al, 2007;Schneider et al, 2011). However, we clarify that the retrieval of background-continuum does not correct imperfect spectral modelling of line shapes, but rather might partially compensate net-effects resulting from incorrectly modelled line-wings of adjacent spectral signatures.…”