We first design experiments to investigate the sensitivity of ILS (instrumental line shape) monitoring for a high-resolution FTIR spectrometer within the TCCON and NDACC networks with respect to different optical attenuators. The ILS characteristics derived from lamp and sun spectra are in good agreement. A potential strategy to adapt incident intensity of a detector was deduced.
We first design experiments to investigate the sensitivity of ILS (instrumental line shape)...
Technical note: Sensitivity of instrumental line shape monitoring for the ground-based high-resolution FTIR spectrometer with respect to different optical attenuators
Youwen Sun1,2,*,Mathias Palm3,*,Christine Weinzierl3,Christof Petri3,Justus Notholt3,Yuting Wang3,and Cheng Liu4,2,1Youwen Sun et al.Youwen Sun1,2,*,Mathias Palm3,*,Christine Weinzierl3,Christof Petri3,Justus Notholt3,Yuting Wang3,and Cheng Liu4,2,1
Received: 06 Jan 2016 – Discussion started: 08 Mar 2016 – Revised: 17 Sep 2016 – Accepted: 11 Oct 2016 – Published: 13 Mar 2017
Abstract. The TCCON (Total Carbon Column Observing Network) and most NDACC (Network for Detection of Atmospheric Composition Change) sites assume an ideal ILS (instrumental line shape) for analysis of the spectra. In order to adapt the radiant energy received by the detector, an attenuator or different sizes of field stop can be inserted in the light path. These processes may alter the alignment of a high-resolution FTIR (Fourier transform infrared) spectrometer, and may result in bias due to ILS drift. In this paper, we first investigated the sensitivity of the ILS monitoring with respect to application of different kinds of attenuators for ground-based high-resolution FTIR spectrometers within the TCCON and NDACC networks. Both lamp and sun cell measurements were conducted after the insertion of five different attenuators in front of and behind the interferometer. The ILS characteristics derived from lamp and sun spectra are in good agreement. ILSs deduced from all lamp cell measurements were compared. As a result, the disturbances to the ILS of a high-resolution FTIR spectrometer with respect to the insertion of different attenuators at different positions were quantified. A potential strategy to adapt the incident intensity of a detector was finally deduced.
We first design experiments to investigate the sensitivity of ILS (instrumental line shape) monitoring for a high-resolution FTIR spectrometer within the TCCON and NDACC networks with respect to different optical attenuators. The ILS characteristics derived from lamp and sun spectra are in good agreement. A potential strategy to adapt incident intensity of a detector was deduced.
We first design experiments to investigate the sensitivity of ILS (instrumental line shape)...