https://escholarship.org/content/qt7gh3p3z1/qt7gh3p3z1.pdf?t=qgqugr

The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018

A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmosphere. The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres. Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere, a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 Wm−2 daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude. The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover.

On the Radiative Forcing by Contrails

EU ETS versus CORSIA – A critical assessment of two approaches to limit air transport's CO2 emissions by market-based measures

Unstart phenomena induced by flow choking in scramjet inlet-isolators

This paper aims at exploring the perspective of sustainability when digital transformation is adopted by one organization, although it was not the first goal targeted. Two different cases are analyzed, covering manufacturing and service industries. In those cases different factors will be analyzed, mainly focused on the positive effects of knowledge creation facilitated by direct or indirect application of digitalization. Specific analysis of different cases were carried out to identify different initiatives and the impact on environmental performance. The positive effects of the institutional dimension were also assessed.

Digitalization: An Opportunity for Contributing to Sustainability From Knowledge Creation

An operational measure that is inspired by migrant birds aiming toward the mitigation of aviation climate impact is to fly in aerodynamic formation. When this operational measure is adapted to commercial aircraft it saves fuel and is, therefore, expected to reduce the climate impact of aviation. Besides the total emission amount, this mitigation option also changes the location of emissions, impacting the non-CO2 climate effects arising from NOx and H2O emissions and contrails. Here, we assess these non-CO2 climate impacts with a climate response model to assure a benefit for climate not only due to CO2 emission reductions, but also due to reduced non-CO2 effects. Therefore, the climate response model AirClim is used, which includes CO2 effects and also the impact of water vapor and contrail induced cloudiness as well as the impact of nitrogen dioxide emissions on the ozone and methane concentration. For this purpose, AirClim has been adopted to account for saturation effects occurring for formation flight. The results of the case studies show that the implementation of formation flights in the 50 most popular airports for the year 2017 display an average decrease of fuel consumption by 5%. The climate impact, in terms of average near surface temperature change, is estimated to be reduced in average by 24%, with values of individual formations between 13% and 33%.

https://www.mdpi.com/2226-4310/7/12/172/pdf

Assessing the climate impact of formation flights

Climate assessment of single flights: Deduction of route specific equivalent CO2 emissions

Wing configuration effects on flow field and aerodynamic performance of supersonic biplane for sonic-boom reduction

. Climate impact of aviation is expected to increase further. Aircraft routings are an important measure for climate impact reductions. To find an effective aircraft routing strategy for reducing the impact, the first version of the submodel AirTraf has been developed; this submodel can simulate global air traffic in the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. This paper describes the updated submodel AirTraf 2.0. Seven new aircraft routing options are introduced, including contrail avoidance, minimum economic costs, and minimum climate impact. Example simulations of the new routing options are presented by using around 100 north-Atlantic flights of an Airbus A330 aircraft for a typical winter day. The results clearly show that the family of optimum flight trajectories (three-dimensional) varies according to the routing options. The comparison of the results for various routing options reveals characteristics of the routing with respect to air traffic performances. The minimum cost option obtains a trade-off solution between the minimum time and the minimum fuel solutions. The aircraft routings for contrail avoidance and minimum climate impact reduce the potential climate impact, which is estimated by using algorithmic Climate Change Functions, whereas these two routings increase flight operating costs. A trade-off between the aircraft operating costs and the climate impact is confirmed. The simulation results are compared with literature data and the consistency of the submodel AirTraf 2.0 is verified.

/pdf/various-aircraft-routing-options-for-air-traffic-simulation-a36c6fwse0.pdf

Hiroshi Yamashita

Papers

Assessing the climate impact of formation flights

Climate assessment of single flights: Deduction of route specific equivalent CO2 emissions

Wing configuration effects on flow field and aerodynamic performance of supersonic biplane for sonic-boom reduction

Various aircraft routing options for air traffic simulation in the chemistry-climate model EMAC 2.53: AirTraf 2.0

Climate impact assessment of routing strategies: Interactive air traffic in a climatemodel