arXiv subjects

Megan Ryerson

Publications and source records attributed to Megan Ryerson.

3 recordsLinked to original sources

arXiv2025

Identification and Characterization for Disruptions in the U.S. National Airspace System (NAS)

Disruptions in the National Airspace System (NAS) lead to significant losses to air traffic system participants and raise public concerns. We apply two methods, cluster analysis and anomaly detection models, to identify operational disruptions with geographical patterns in the NAS since 2010. We identify four types and twelve categories of days of operations, distinguished according to air traffic system operational performance and geographical patterns of disruptions. Two clusters--NAS Disruption and East Super Disruption, accounting for 0.8% and 1.2% of the days respectively, represent the most disrupted days of operations in U.S. air traffic system. Another 16.5% of days feature less severe but still significant disruptions focused on certain regions of the NAS, while on the remaining 81.5% of days the NAS operates relatively smoothly. Anomaly detection results show good agreement with cluster results and further distinguish days in the same cluster by severity of disruptions. Results show an increasing trend in frequency of disruptions especially post-COVID. Additionally, disruptions happen most frequently in the summer and winter.

eess.SY↗

arXiv2023

Equitable Optimization of U.S. Airline Route Networks

Restructuring route networks (i.e., modifying the graph of origin-destination pairs) remains a promising alternative for reducing the airline industry's environmental impact. However, there exists a fundamental trade-off between emissions from flight and airport accessibility, since flights connecting underserved, low-accessibility communities tend to possess high CO2 per seat-mile ratios. Thus, this work develops an open-source analytical framework and methodology that restructures U.S. airline route networks to simultaneously minimize emissions and maximize airport accessibility. To achieve this goal, this paper designs a metric to quantify airport accessibility and combines it with an open-source system-wide emissions estimation methodology. This facilitates the creation of a mixed-integer linear optimization model that returns revised flight frequencies and aircraft allotment. Using United Airlines 2019 Q3 data as a case study, this model is able to construct an alternative route network with a 25% reduction on the total number of flights, 4.4% decrease in the average emissions per seat-mile and a 17.6% improvement in the spread of the airports' accessibility scores, all while satisfying historic passenger demand.

physics.soc-ph↗

arXiv2022

Democratizing Aviation Emissions Estimation: Development of an Open-Source, Data-Driven Methodology

Through an aviation emissions estimation tool that is both publicly-accessible and comprehensive, researchers, planners, and community advocates can help shape a more sustainable and equitable U.S. air transportation system. To this end, we develop an open-source, data-driven methodology to calculate the system-wide emissions of the U.S. domestic civil aviation industry. This process utilizes and integrates six different public datasets provided by the Bureau of Transportation Statistics (BTS), the Federal Aviation Agency (FAA), EUROCONTROL, and the International Civil Aviation Organization (ICAO). At the individual flight level, our approach examines the specific aircraft type, equipped engine, and time in stage of flight to produce a more granular estimate than competing approaches. Enabled by our methodology, we then calculate system-wide emissions, considering four different greenhouse gases (CO2, NOx, CO, HC) during the Landing, Take-off (LTO) and Climb, Cruise, and Descent (CCD) flight cycles. Our results elucidate that emissions on a particular route can vary significantly due to aircraft and engine choice, and that emission rates differ significantly from airline to airline. We also find that CO2 alone is not a sufficient proxy for emissions, as NOx, when converted to its CO2-equivalency, exceeds CO2 during both LTO and CCD.

stat.AP↗