Florian Linke

Bio: Florian Linke is an academic researcher from German Aerospace Center. The author has contributed to research in topics: Air traffic control & Aviation. The author has an hindex of 14, co-authored 60 publications receiving 552 citations. Previous affiliations of Florian Linke include Hamburg University of Technology.

Temporal evolution analysis of the European air transportation system: air navigation route network and airport network

Abstract: Airspace is a networked space that constantly changes in order to adapt with the changing demand of air traffic. The goal of this research is to study the temporal evolution of the European air transportation system. We analyse two network layers: the air navigation route network and the airport network. For each network layer, we analyse the temporal evolution of seven centrality measures. We quantify the seasonal and weekly variation patterns by the coefficient of variation. We find that the air navigation route network is dominated by the summer/winter seasonal variations, while the airport network shows both summer/winter seasonal variations and peak/off-peak weekly patterns. From the distributions of the metrics, we find that hub nodes existing in both network layers are potentially bottlenecks of the network. Our research helps the stakeholders in air transportation systems to monitor the network performance over time and to better understand the network dynamics.

Evaluating the climate impact of aviation emission scenarios towards the Paris agreement including COVID-19 effects.

Abstract: Aviation is an important contributor to the global economy, satisfying society’s mobility needs. It contributes to climate change through CO2 and non-CO2 effects, including contrail-cirrus and ozone formation. There is currently significant interest in policies, regulations and research aiming to reduce aviation’s climate impact. Here we model the effect of these measures on global warming and perform a bottom-up analysis of potential technical improvements, challenging the assumptions of the targets for the sector with a number of scenarios up to 2100. We show that although the emissions targets for aviation are in line with the overall goals of the Paris Agreement, there is a high likelihood that the climate impact of aviation will not meet these goals. Our assessment includes feasible technological advancements and the availability of sustainable aviation fuels. This conclusion is robust for several COVID-19 recovery scenarios, including changes in travel behaviour.

A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories

Abstract: Comprehensive assessment of the environmental aspects of flight movements is of increasing interest to the aviation sector as a potential input for developing sustainable aviation strategies that consider climate impact, air quality and noise issues simultaneously. However, comprehensive assessments of all three environmental aspects do not yet exist and are in particular not yet operational practice in flight planning. The purpose of this study is to present a methodology which allows to establish a multi-criteria environmental impact assessment directly in the flight planning process. The method expands a concept developed for climate optimisation of aircraft trajectories, by representing additionally air quality and noise impacts as additional criteria or dimensions, together with climate impact of aircraft trajectory. We present the mathematical framework for environmental assessment and optimisation of aircraft trajectories. In that context we present ideas on future implementation of such advanced meteorological services into air traffic management and trajectory planning by relying on environmental change functions (ECFs). These ECFs represent environmental impact due to changes in air quality, noise and climate impact. In a case study for Europe prototype ECFs are implemented and a performance assessment of aircraft trajectories is performed for a one-day traffic sample. For a single flight fuel-optimal versus climate-optimized trajectory solution is evaluated using prototypic ECFs and identifying mitigation potential. The ultimate goal of such a concept is to make available a comprehensive assessment framework for environmental performance of aircraft operations, by providing key performance indicators on climate impact, air quality and noise, as well as a tool for environmental optimisation of aircraft trajectories. This framework would allow studying and characterising changes in traffic flows due to environmental optimisation, as well as studying trade-offs between distinct strategic measures.

Climate-Compatible Air Transport System—Climate Impact Mitigation Potential for Actual and Future Aircraft

Abstract: Aviation guarantees mobility, but its emissions also contribute considerably to climate change. Therefore, climate impact mitigation strategies have to be developed based on comprehensive assessments of the different impacting factors. We quantify the climate impact mitigation potential and related costs resulting from changes in aircraft operations and design using a multi-disciplinary model workflow. We first analyze the climate impact mitigation potential and cash operating cost changes of altered cruise altitudes and speeds for all flights globally operated by the Airbus A330-200 fleet in the year 2006. We find that this globally can lead to a 42% reduction in temperature response at a 10% cash operating cost increase. Based on this analysis, new design criteria are derived for future aircraft that are optimized for cruise conditions with reduced climate impact. The newly-optimized aircraft is re-assessed with the developed model workflow. We obtain additional climate mitigation potential with small to moderate cash operating cost changes due to the aircraft design changes of, e.g., a 32% and 54% temperature response reduction for a 0% and 10% cash operating cost increase. Hence, replacing the entire A330-200 fleet by this redesigned aircraft ( M a c r = 0.72 and initial cruise altitude (ICA) = 8000 m) could reduce the climate impact by 32% without an increase of cash operating cost.

Annual review 腎臓

Abstract: １ Ｂａｓｉｃ ｎｅｐｈｒｏｌｏｇｙ（生理；免疫・病理；分子生物学；検査・診断） ２ Ｃｌｉｎｉｃａｌ ｎｅｐｈｒｏｌｏｇｙ（糸球体障害；尿細管・間質障害；全身性疾患と腎障害；水電解質異常；腎不全）

Strengthening and Implementing the Global Response

Abstract: The global response to warming of 1.5oC comprises transitions in land and ecosystem, energy, urban and infrastructure, and industrial systems. The feasibility of mitigation and adaptation options, and the enabling conditions for strengthening and implementing the systemic changes, are assessed in this chapter.

Formation and radiative forcing of contrail cirrus

Abstract: Aircraft-produced contrail cirrus clouds contribute to anthropogenic climate change. Observational data sets and modelling approaches have become available that clarify formation pathways close to the source aircraft and lead to estimates of the global distribution of their microphysical and optical properties. While contrail cirrus enhance the impact of natural clouds on climate, uncertainties remain regarding their properties and lifecycle. Progress in representing aircraft emissions, contrail cirrus and natural cirrus in global climate models together with tighter constraints on the sensitivity of the climate system will help judge efficiencies of and trade-offs between mitigation options.

On the Radiative Forcing by Contrails

Abstract: 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.