Predicting the climate impact of aviation for en-route emissions: The algorithmic climate change function submodel ACCF 1.0 of EMAC 2.53

Abstract

Abstract. The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a base model via a modular flexible data management facility. This paper presents the newly developed MESSy submodel, ACCF version 1.0 (ACCF 1.0), based on algorithmic Climate Change Functions version 1.0 (aCCFs 1.0), which describes the climate impact of aviation emissions. The ACCF 1.0 is coupled via the second version of the standard MESSy infrastructure. ACCF 1.0 takes the simulated atmospheric conditions at the location of emission as input to calculate the climate impact (in terms of average temperature response over 20 years (ATR20)) of aviation emissions, including CO2 and non-CO2 impacts, such as from NOx emissions (via ozone production and methane destruction), water vapour emissions, and contrail-cirrus. The online calculated ATR20 value per emitted mass fuel burn or flown-kilometer using ACCF 1.0 in the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model is presented. We perform quality checks of the ACCF 1.0 outputs in two aspects. Firstly, we compare climatological values calculated by the ACCF 1.0 to previous studies. Secondly, we evaluate the reduction of NOx-induced O3 effects through trajectory optimization, employing the tagging chemistry approach (contribution approach to tag species according to their emission categories and to inherit these tags to other species during the subsequent chemical reactions). Finally, we couple the ACCF 1.0 to the air traffic simulation submodel AirTraf version 2.0 and demonstrate the variability of the flight trajectories when the efficacy of individual effect is considered.

A python library for computing individual and merged non-CO2 algorithmic climate change functions: CLIMaCCF V1.0

“…Nevertheless, it was shown that these aCCFs are in broad agreement with the climate change metric of earlier studies (e.g. van Manen and Grewe, 2019;Yin et al, 2022).…”

“…The algorithm for contrail aCCFs was developed differently. Contrail aCCFs are obtained from contrail radiative forcing calculations which are based on ERA-Interim reanalysis data (Dee et al, 2011) and on contrail trajectory data (Yin et al, 2022). A short overview of the mathematical formulation of these emission type dependent prototype aCCFs is given in Appendix A of this document.…”

“…For a detailed description of the first complete and consistent set of prototype aCCFs (aCCF-V1.0) the reader is referred to Yin et al (2022). Moreover, within the EU project FlyATM4E an updated set of aCCFs (aCCF-V1.1) was developed that considers current level of scientific understanding of aviation's climate effects: For more details, readers are referred to Matthes et al (2022, in preparation)..…”

“…For a merged aCCF it is required that the individual aCCFs are based on the same physical climate metric, emission scenario and time horizon. The recent publication of Yin et al (2022) comprises such a consistent set of individual updated prototype aCCFs. Note, that earlier publications (as e.g.…”

“…The emission scenario assumed was either based on pulse emission (P) or on the future business as usual emission scenario (F). This inconsistency has been discovered and a revision of the aCCFs is given in the recent publication of Yin et al (2022). Now all direct outputs of aCCF formulas are given in P-ATR20 (ATR20 based on pulse emission).…”