Climate-Optimized Trajectories and Robust Mitigation Potential: Flying ATM4E

Aviation can reduce its climate impact by controlling its CO2-emission and non-CO2 effects, e.g., aviation-induced contrail-cirrus and ozone caused by nitrogen oxide emissions. One option is the implementation of operational measures that aim to avoid those atmospheric regions that are in particular sensitive to non-CO2 aviation effects, e.g., where persistent contrails form. The quantitative estimates of mitigation potentials of such climate-optimized aircraft trajectories are required, when working towards sustainable aviation. The results are presented from a comprehensive modelling approach when aiming to identify such climate-optimized aircraft trajectories. The overall concept relies on a multi-dimensional environmental change function concept, which is capable of providing climate impact information to air traffic management (ATM). Estimates on overall climate impact reduction from a one-day case study are presented that rely on the best estimate for climate impact information. Specific weather situation that day, containing regions with high contrail impact, results in a potential reduction of total climate impact, by more than 40%, when considering CO2 and non-CO2 effects, associated with an increase of fuel by about 0.5%. The climate impact reduction per individual alternative trajectory shows a strong variation and, hence, also the mitigation potential for an analyzed city pair, depending on atmospheric characteristics along the flight corridor as well as flight altitude. The robustness of proposed climate-optimized trajectories is assessed by using a range of different climate metrics. A more sustainable ATM needs to integrate comprehensive environmental impacts and associated forecast uncertainties into route optimization in order to identify robust eco-efficient trajectories.

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Climate Impact Mitigation Potential of European Air Traffic in a Weather Situation with Strong Contrail Formation

Aerospace ◽

10.3390/aerospace8020050 ◽

2021 ◽

Vol 8 (2) ◽

pp. 50

Author(s):

Benjamin Lührs ◽

Florian Linke ◽

Sigrun Matthes ◽

Volker Grewe ◽

Feijia Yin

Keyword(s):

Climate Change ◽

Trajectory Optimization ◽

Climate Impact ◽

Air Traffic ◽

Mitigation Measures ◽

Aviation Industry ◽

Impact Mitigation ◽

Impact Reduction ◽

Fuel Burn ◽

Weather Situation

Air traffic contributes to anthropogenic global warming by about 5% due to CO2 emissions and non-CO2 effects, which are primarily caused by the emission of NOx and water vapor as well as the formation of contrails. Since—in the long term—the aviation industry is expected to maintain its trend to grow, mitigation measures are required to counteract its negative effects upon the environment. One of the promising operational mitigation measures that has been a subject of the EU project ATM4E is climate-optimized flight planning by considering algorithmic climate change functions that allow for the quantification of aviation-induced climate impact based on the emission’s location and time. Here, we describe the methodology developed for the use of algorithmic climate change functions in trajectory optimization and present the results of its application to the planning of about 13,000 intra-European flights on one specific day with strong contrail formation over Europe. The optimization problem is formulated as bi-objective continuous optimal control problem with climate impact and fuel burn being the two objectives. Results on an individual flight basis indicate that there are three major classes of different routes that are characterized by different shapes of the corresponding Pareto fronts representing the relationship between climate impact reduction and fuel burn increase. On average, for the investigated weather situation and traffic scenario, a climate impact reduction in the order of 50% can be achieved by accepting 0.75% of additional fuel burn. Higher mitigation gains would only be available at much higher fuel penalties, e.g., a climate impact reduction of 76% associated with a fuel penalty of 12.8%. However, these solutions represent much less efficient climate impact mitigation options.

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Influence of the actual weather situation on non-CO<sub>2</sub> aviation climate effects: The REACT4C Climate Change Functions

10.5194/acp-2020-529 ◽

2020 ◽

Cited By ~ 1

Author(s):

Christine Frömming ◽

Volker Grewe ◽

Sabine Brinkop ◽

Patrick Jöckel ◽

Amund S. Haslerud ◽

...

Keyword(s):

Climate Change ◽

North Atlantic ◽

Climate Impact ◽

Flight Trajectory ◽

Atlantic Region ◽

The North ◽

Weather Situation ◽

Aviation Emissions ◽

Aircraft Trajectories ◽

Local Emissions

Abstract. Emissions of aviation include CO2, H2O, NOx, sulfur oxides and soot. Many studies have investigated the annual mean climate impact of aviation emissions. While CO2 has a long atmospheric residence time and is almost uniformly distributed in the atmosphere, non-CO2 gases, particles and their products have short atmospheric residence times and are heterogeneously distributed. The climate impact of non-CO2 aviation emissions is known to vary with different meteorological background situations. The aim of this study is to systematically investigate the influence of different weather situations on aviation climate effects over the North Atlantic region, to identify the most sensitive areas and potentially detect systematic weather related similarities. If aircraft were re-routed to avoid climate-sensitive regions, the overall aviation climate Impact might be reduced. Hence, the sensitivity of the atmosphere to local emissions provides a basis for the assessment of weather related, climate optimized flight trajectory planning. To determine the climate change contribution of an individual Emission as function of location, time and weather situation, the radiative impact of local emissions of NOx and H2O to changes in O3, CH4, H2O and contrail-cirrus was computed by means of the ECHAM5/MESSy Atmospheric Chemistry model. 4-dimensional climate change functions (CCFs) were derived thereof. Typical weather situations in the North Atlantic region were considered for winter and summer. Weather related differences in O3-, CH4-, H2O-, and contrail-cirrus-CCFs were investigated. The following characteristics were identified: Enhanced climate impact of contrail-cirrus was detected for emissions in areas with large scale lifting, whereas low climate impact of contrail-cirrus was found in the area of the jet stream. Northwards of 60° N contrails usually cause climate warming in winter, independent of the weather situation. NOx emissions cause a high positive climate impact if released in the area of the jet stream or in high pressure ridges, which induces a south- and downward transport of the emitted species. Whereas NOx emissions at, or transported towards high latitudes, cause low or even negative climate impact. Independent of the weather situation, total NOx effects show a minimum at ∼250 hPa, increasing towards higher and lower altitudes, with generally higher positive impact in summer than in winter. H2O emissions induce a high climate Impact when released in regions with lower tropopause height, whereas low climate impact occurs for emissions in areas with higher tropopause height. H2O-CCFs generally increase with height, and are larger in winter than in summer. The CCFs of all individual species can be combined, facilitating the assessment of total climate impact of aircraft trajectories considering CO2 and spatially and temporally varying non-CO2 effetcs. Furthermore they allow the optimization of aircraft trajectories with reduced overall climate impact. In most regions NOx and contrail-cirrus dominate the sensitivity to local aviation emissions. The findings of this study recommend, to consider weather related differences for flight trajectory optimization in favour of reducing total climate impact.

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Influence of weather situation on non-CO<sub>2</sub> aviation climate effects: the REACT4C climate change functions

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-9151-2021 ◽

2021 ◽

Vol 21 (11) ◽

pp. 9151-9172

Author(s):

Christine Frömming ◽

Volker Grewe ◽

Sabine Brinkop ◽

Patrick Jöckel ◽

Amund S. Haslerud ◽

...

Keyword(s):

Climate Change ◽

North Atlantic ◽

Climate Impact ◽

Individual Species ◽

Flight Trajectory ◽

The North ◽

Weather Situation ◽

Aviation Emissions ◽

Aircraft Trajectories ◽

Local Emissions

Abstract. Emissions of aviation include CO2, H2O, NOx, sulfur oxides, and soot. Many studies have investigated the annual mean climate impact of aviation emissions. While CO2 has a long atmospheric residence time and is almost uniformly distributed in the atmosphere, non-CO2 gases and particles and their products have short atmospheric residence times and are heterogeneously distributed. The climate impact of non-CO2 aviation emissions is known to vary with different meteorological background situations. The aim of this study is to systematically investigate the influence of characteristic weather situations on aviation climate effects over the North Atlantic region, to identify the most sensitive areas, and to potentially detect systematic weather-related similarities. If aircraft were re-routed to avoid climate-sensitive regions, the overall aviation climate impact might be reduced. Hence, the sensitivity of the atmosphere to local emissions provides a basis for the assessment of weather-related, climate-optimized flight trajectory planning. To determine the climate change contribution of an individual emission as a function of location, time, and weather situation, the radiative impact of local emissions of NOx and H2O to changes in O3, CH4, H2O and contrail cirrus was computed by means of the ECHAM5/MESSy Atmospheric Chemistry model. From this, 4-dimensional climate change functions (CCFs) were derived. Typical weather situations in the North Atlantic region were considered for winter and summer. Weather-related differences in O3, CH4, H2O, and contrail cirrus CCFs were investigated. The following characteristics were identified: enhanced climate impact of contrail cirrus was detected for emissions in areas with large-scale lifting, whereas low climate impact of contrail cirrus was found in the area of the jet stream. Northwards of 60∘ N, contrails usually cause climate warming in winter, independent of the weather situation. NOx emissions cause a high positive climate impact if released in the area of the jet stream or in high-pressure ridges, which induces a south- and downward transport of the emitted species, whereas NOx emissions at, or transported towards, high latitudes cause low or even negative climate impact. Independent of the weather situation, total NOx effects show a minimum at ∼250 hPa, increasing towards higher and lower altitudes, with generally higher positive impact in summer than in winter. H2O emissions induce a high climate impact when released in regions with lower tropopause height, whereas low climate impact occurs for emissions in areas with higher tropopause height. H2O CCFs generally increase with height and are larger in winter than in summer. The CCFs of all individual species can be combined, facilitating the assessment of total climate impact of aircraft trajectories considering CO2 and spatially and temporally varying non-CO2 effects. Furthermore, they allow for the optimization of aircraft trajectories with reduced overall climate impact. This also facilitates a fair evaluation of trade-offs between individual species. In most regions, NOx and contrail cirrus dominate the sensitivity to local aviation emissions. The findings of this study recommend considering weather-related differences for flight trajectory optimization in favour of reducing total climate impact.

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Evaluation of the Climate Impact Reduction Potential of the Water-Enhanced Turbofan (WET) Concept

Aerospace ◽

10.3390/aerospace8030059 ◽

2021 ◽

Vol 8 (3) ◽

pp. 59

Author(s):

Regina Pouzolz ◽

Oliver Schmitz ◽

Hermann Klingels

Keyword(s):

Co2 Emissions ◽

Aircraft Engine ◽

Steam Injection ◽

Climate Impact ◽

Formation Mechanisms ◽

Water Recovery ◽

Impact Reduction ◽

Fuel Burn ◽

Starting Point ◽

Reduction Of Co2

Aviation faces increasing pressure not only to reduce fuel burn, and; therefore, CO2 emissions, but also to provide technical solutions for an overall climate impact minimization. To combine both, a concept for the enhancement of an aircraft engine by steam injection with inflight water recovery is being developed. The so-called Water-Enhanced Turbofan (WET) concept promises a significant reduction of CO2 emissions, NOx emissions, and contrail formation. Representative missions for an A320-type aircraft using the proposed new engine were calculated. Applying a first-order one-dimensional climate assessment prospects the reduction of more than half of the Global Warming Potential over one hundred years, compared to an evolutionarily improved aero-engine. If CO2-neutrally produced sustainable aviation fuels are used, climate impact could be reduced by 93% compared to today’s aircraft. The evaluation is a first estimate of effects based on preliminary design studies and should provide a starting point for discussion in the scientific community, implying the need for research, especially on the formation mechanisms and radiation properties of potential contrails from the comparatively cold exhaust gases of the WET engine.

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Neural Network-Based Aircraft Conflict Prediction in Final Approach Maneuvers

Electronics ◽

10.3390/electronics9101708 ◽

2020 ◽

Vol 9 (10) ◽

pp. 1708

Author(s):

Rafael Casado ◽

Aurelio Bermúdez

Keyword(s):

Neural Network ◽

Traffic Management ◽

Autonomous Navigation ◽

Decision Support Tool ◽

Air Traffic ◽

Navigation Systems ◽

Support Tool ◽

Final Approach ◽

Aircraft Trajectories ◽

Available Information

Conflict detection and resolution is one of the main topics in air traffic management. Traditional approaches to this problem use all the available information to predict future aircraft trajectories. In this work, we propose the use of a neural network to determine whether a particular configuration of aircraft in the final approach phase will break the minimum separation requirements established by aviation rules. To achieve this, the network must be effectively trained with a large enough database, in which configurations are labeled as leading to conflict or not. We detail the way in which this training database has been obtained and the subsequent neural network design and training process. Results show that a simple network can provide a high accuracy, and therefore, we consider that it may be the basis of a useful decision support tool for both air traffic controllers and airborne autonomous navigation systems.

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Consumer Preferences for Different Designs of Carbon Footprint Labelling on Tomatoes in Germany—Does Design Matter?

Sustainability ◽

10.3390/su11061587 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1587 ◽

Cited By ~ 7

Author(s):

Stephan Meyerding ◽

Anna-Lena Schaffmann ◽

Mira Lehberger

Keyword(s):

Carbon Footprint ◽

Choice Experiment ◽

Latent Class ◽

Consumer Preferences ◽

Significant Proportion ◽

Climate Impact ◽

Traffic Light ◽

Tomato Production ◽

Impact Reduction ◽

Northern European

The climate impact of tomato production is an important issue in the sustainability of tomatoes, especially in northern European countries, such as Germany. Communicating the climate impact of products to the consumer is difficult and the design of the label might be the key to its success. For this reason, the present study compares the utilities of six different carbon footprint labels to evaluate which label design works best for the consumer. 598 consumers were surveyed in a representative online choice-experiment. The participants had to choose between tomatoes with different product characteristics, such as origin, price, organic label, and carbon footprint label. A split sample approach was used where each sub-sample with around n = 100 saw a different carbon footprint label design in the choice-experiment. The results suggest that qualitative carbon footprint labels using color-coded traffic light labelling are superior to those that claim climate impact reduction or neutrality, including those that provide more details regarding the climate impact of the product and the company. The latent class analysis with four consumer segments shows that a significant proportion of consumers in Germany would consider a carbon footprint label as an important characteristic.

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A volcanic hazard demonstration exercise to assess and mitigate the impacts of volcanic ash clouds on civil and military aviation

10.5194/nhess-2019-265 ◽

2019 ◽

Author(s):

Marcus Hirtl ◽

Delia Arnold ◽

Rocio Baro ◽

Hugues Brenot ◽

Mauro Coltelli ◽

...

Keyword(s):

Traffic Management ◽

Volcanic Eruptions ◽

Route Optimization ◽

Volcanic Plume ◽

Case Scenario ◽

Ensemble Techniques ◽

Current State ◽

Aviation Hazards ◽

Volcanic Cloud ◽

Flight Cancellations

Abstract. Volcanic eruptions comprise one of the most important airborne hazards for aviation. Although significant events are rare, they have a very high impact. The current state of tools and abilities to mitigate aviation hazards associated with an assumed volcanic cloud was tested within an international demonstration exercise. Experts in the field assembled at the Schwarzenberg barracks in Salzburg, Austria, in order to simulate the sequence of procedures for the volcanic case scenario of an artificial eruption of Etna volcano in Italy. The scope of the exercise ranged from the detection of the assumed event to the issuance of early warnings. Volcanic emission concentration charts were generated applying modern ensemble techniques. The exercise products provided an important basis for decision making for aviation traffic management during a volcanic eruption crisis. By integrating the available wealth of data, observations and modelling results directly into a widely used flight planning software, it was demonstrated that route optimization measures could be implemented effectively. With timely and rather precise warnings available, the new tools and processes tested during the exercise demonstrated vividly that a vast majority of flights could be conducted despite a volcanic plume widely dispersed within a high-traffic airspace over Europe. The resulting number of flight cancellations was minimal.

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Assessing the Climate Impact of Formation Flights

Aerospace ◽

10.3390/aerospace7120172 ◽

2020 ◽

Vol 7 (12) ◽

pp. 172 ◽

Cited By ~ 1

Author(s):

Katrin Dahlmann ◽

Sigrun Matthes ◽

Hiroshi Yamashita ◽

Simon Unterstrasser ◽

Volker Grewe ◽

...

Keyword(s):

Climate Impact ◽

Climate Impacts ◽

Response Model ◽

Climate Response ◽

Surface Temperature Change ◽

Near Surface ◽

Average Decrease ◽

Co2 Effects ◽

Saturation Effects ◽

The Impact

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%.

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Guidance for Healthy and More Climate-Friendly Diets in Nursing Homes—Scenario Analysis Based on a Municipality’s Food Procurement

Nutrients ◽

10.3390/nu13124525 ◽

2021 ◽

Vol 13 (12) ◽

pp. 4525

Author(s):

Anne Dahl Lassen ◽

Matilda Nordman ◽

Lene Møller Christensen ◽

Anne Marie Beck ◽

Ellen Trolle

Keyword(s):

Nursing Homes ◽

Protein Content ◽

Food Item ◽

Food System ◽

Climate Impact ◽

Sustainable Food ◽

Menu Planning ◽

Impact Reduction ◽

Food Procurement ◽

Increase Protein Content

Reducing the climate impact of food provided for residents in nursing homes is challenging, as the diets for older, frail adults must be high in protein content and energy density while at the same time ensuring that the meals are palatable and recognizable. This study aimed at providing guidance on healthy and more climate-friendly diets for nursing homes in the City of Copenhagen. The goal was to decrease greenhouse gas emissions (GHGE) by at least 25% while at the same time providing nutritionally adequate and recognizable menus. First, food purchase data were compiled with datasets matching each food item to a proxy food item and then to databases containing GHGE and nutrient information. Secondly, two diet scenarios were modelled based on current procurement practices, i.e., an energy- and protein-dense diet and a standard protein-dense diet, and converted into guidelines for menu planning. The diets contained less total meat, especially beef, and significantly more pulses, nuts and seeds in order to increase protein content according to recommendations for older adults. Finally, a combined scenario was calculated to reflect the joint climate impact reduction. This kind of innovation in food procurement is required in order to achieve the necessary transition to a sustainable food system.

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