The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 2: Aviation

Abstract

Abstract. We use the EMAC (ECHAM/MESSy Atmospheric Chemistry) global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications) to simulate the impact of aviation emissions on global atmospheric aerosol and climate in 2030. Emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs) designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare our findings with the results of a previous study with the same model configuration focusing on year 2000 emissions. We also characterize the aviation results in the context of the other transport sectors presented in a companion paper. In spite of a relevant increase in aviation traffic volume and resulting emissions of aerosol (black carbon) and aerosol precursor species (nitrogen oxides and sulfur dioxide), the aviation effect on particle mass concentration in 2030 remains quite negligible (on the order of a few ng m −3 ), about 1 order of magnitude less than the increase in concentration due to other emission sources. Due to the relatively small size of the aviation-induced aerosol, however, the increase in particle number concentration is significant in all scenarios (about 1000 cm −3 ), mostly affecting the northern mid-latitudes at typical flight altitudes (7-12 km). This largely contributes to the overall change in particle number concentration between 2000 and 2030, which also results in significant climate effects due to aerosol-cloud interactions. Aviation is the only transport sector for which a larger impact on the Earth's radiation budget is simulated in the future: the aviation-induced radiative forcing in 2030 is more than doubled with respect to the year 2000 value of −15 mW m −2 in all scenarios, with a maximum value of −63 mW m −2 simulated for RCP2.6.

Implementation of a comprehensive ice crystal formation parameterization for cirrus and mixed-phase clouds in the EMAC model (based on MESSy 2.53)

“…The EMAC model is a numerical chemistry-climate model which describes tropospheric and middle-atmosphere processes and their interactions with ocean, land, and human influences. Such interactions are simulated via dedicated submodels in the MESSy framework (Modular Earth Submodel System; Jöckel et al, 2010), while the 5th generation European Centre Hamburg GCM (ECHAM5; Roeckner et al, 2006) is used as core of the atmospheric dynamics. For the present study we have used ECHAM5 version 5.3.02 and MESSy version 2.53.…”

Feasibility of climate-optimized air traffic routing for trans-Atlantic flights

“…Recent studies (e.g. Gettleman and Chen 2013, Righi et al 2016, Kapadia et al 2016 indicate that these effects may be substantial, but also that there are large uncertainties in their quantification. We have enough information and knowledge about major atmospheric processes to start the implementation and demonstration in an operational environment.…”

Supplementary material to "Global aerosol modeling with MADE3 (v3.0) in EMAC (based on v2.53): model description and evaluation"

“…It uses the second version of MESSy to link multiinstitutional computer codes. The core atmospheric model is the ECHAM5 (fifth-generation European Centre Hamburg) general circulation model (Roeckner et al, 2006). For the present study, we applied EMAC (ECHAM5 version 5.3.02, MESSy version 2.53) in the T42L19 resolution, i.e., with a spherical truncation of T42 (corresponding to a quadratic Gaussian grid of approximately 2.8 by 2.8 degrees in latitude and longitude) with 19 vertical hybrid sigma-pressure levels up to 10 hPa.…”

“…Cloud properties are calculated by the submodels CLOUD (stratiform clouds) and CONVECT (convective clouds) in EMAC. For stratiform clouds, we selected the standard ECHAM5 single-moment cloud scheme (Roeckner et al, 2003), i.e., a scheme that only considers water and ice mass but no droplet or ice crystal numbers. Although previous studies with the MADE3 predecessors were carried out with two-moment cloud schemes, a single-moment scheme is sufficient here, as we do not attempt to quantify the climatic impact of aerosol particles.…”

“…This will be the subject of follow-up studies, however. Instead of the Tompkins (2002) method to calculate fractional cloud cover (as described by Roeckner et al, 2003), we choose the parameterization developed by Sundqvist et al (1989). The high numerical stability of this scheme is advantageous for multi-year climate simulations.…”