Impacts of Climate Variability on Commercial Aviation Operations

Weather creates numerous operational and safety hazards within the National Airspace System (NAS). In 2014, extreme weather events attributed to 4.3% of the total number of delay minutes recorded by the Bureau of Transportation Statistics. When factoring weather's impact on the NAS delays and aircraft arriving late delays, weather was responsible for 32.6% of the total number of delay minutes recorded. Weather can also impact the economic performance of an operator by changing fuel requirements, weight and load limitations, and flight planning required during certain weather conditions thereby changing the fuel burn or usable load of flight. Today, a majority of the airlines utilize a hub-and-spoke route network to focus routes onto key airports (i.e. hubs) through which passengers can make connecting flights to smaller airports (i.e. spokes). Weather can prove especially threatening to this kind of route structure because one weather event at a key hub can cause cascading ripples throughout an airline's network. Hourly surface observations collected at major airports called METARs can be used to provide valuable insight into the likely causes of weather delays at individual airports. When combined with the Federal Aviation Administration's (FAA) Operations Network (OPSNET) delay data, METARs can be used to identify the major causes of weather delays and to create delay climatologies for specific airports. Also, long term trends for individual airports can be identified and used by operators and airport planners to optimize performance in the future.

The impact of climate variability has been seen in numerous studies; however teleconnections from various climate modes, such as in the El Nino-Southern Oscillation (ENSO) or the North Atlantic Oscillation (NAO), have not been applied directly to commercial aviation operations. These climatic modes can be quantitatively understood by using the climate indices provided by the National Climatic Data Center. By combining climate indices with surface observations, the influence of climate variability on aviation operations can be better understood. Changes in weather patterns that can create delays and economic loses, such as increases or decreases in snowstorm or low cloud ceiling frequencies, associated with different climatic modes can then be identified.

To better understand the impacts climate variability has on commercial aviation operations, METARs can be used to identify and focus on conditions most likely to create weather delays, decrease efficiency, and require more flight planning, such as weather likely to cause Instrument Flight Rules (IFR) conditions. This information can then be compared with recorded airline delay statistics to determine if climate variability has any influence on overall operations. The primary focus will be on airports in different regions of the United States with large volumes of commercial traffic (i.e. different regional airport hubs). Preliminary results using METAR data from three Dallas – Fort Worth area airports have shown varying trends in visibility, cloud ceiling height, temperature, precipitation, and wind speed and direction, and present weather type that can be linked to different ENSO phases. Later when combined with delay data from Dallas Love Airport and Dallas – Fort Worth International Airport, the influence of the ENSO phase on delays or impacts to efficiency can be assessed. Ultimately, this information can be used to develop probabilistic long term forecasts for specific key airports within an operator's network. With the use of these forecasts, commercial operators can better make adjustments to routes, equipment locations, and overall operations to minimize delays within the network and maximize economic gains.