CO2 and O2 spectroscopy improvements: impacts on XCO2 retrieved from OCO-2 observations

Matthieu Dogniaux,  LMD / IPSL,  matthieu.dogniaux@lmd.ipsl.fr (Presenter)
Thibault Delahaye,  LMD / IPSL,  thibault.delahaye@lmd.ipsl.fr
Raymond Armante,  LMD / IPSL,  raymond.armante@lmd.ipsl.fr
Virginie Capelle,  LMD / IPSL,  virginie.capelle@lmd.ipsl.fr
Vincent Cassé,  LMD / IPSL,  vincent.casse@lmd.ipsl.fr
Cyril Crevoisier,  LMD / IPSL,  cyril.crevoisier@lmd.ipsl.fr
Lilian Joly,  GSMA, UMR CNRS 7331, Université de Reims,  lilian.joly@univ-reims.fr

Several satellite missions have been designed during the past decades in order to retrieve the atmospheric concentrations of CO2, initiating worldwide efforts towards better monitoring of its sources and sinks. The hyperspectral infrared spectra these missions provide are processed by using inverse radiative transfer that enables to interpret measured atmospheric absorptions in terms of column-averaged dry-air mole fraction of CO2 (hereafter XCO2). This method fundamentally relies on the knowledge of molecular spectroscopy that describes how CO2 and possible interfering gases absorb atmospheric radiation. In this work, we present recent spectroscopic parameter improvements for O2 in the 0.76 µm spectral band (empirical correction of the collision-induced absorption) and for CO2 in the 1.6 and 2.05 µm spectral bands (evolutions in spectroscopic parameters and line-mixing). We first show that they reduce 'calculated - observed' spectral residuals computed for measurements made by the ground-based Total Carbon Column Observing Network (TCCON). Then, we assess their impact on XCO2 retrieved from OCO-2 measurements, and compare the results against TCCON official products and vertical CO2 concentration profiles acquired during the 2019 Monitoring of Atmospheric composition and Greenhouse gases through mutli-Instruments Campaign (MAGIC). These results exhibit the interest of vertical concentration profile measurements co-located with satellite soundings for the validation of both forward radiative transfer modeling and inverse setup choices. They finally underline the critical importance of pursed efforts in the improvements of spectroscopic parameters for the interpretation of infrared spectra provided by greenhouse gas monitoring missions.

Poster: Poster_Dogniaux__136_25.pdf 

Presentation Type: Poster

Session: 1.5a Results from current missions

Session Date: Monday (6/14) 12:00 PM