13th Conference on Applied Climatology and the 10th Conference on Aviation, Range, and Aerospace Meteorology

Monday, 13 May 2002: 4:00 PM
Mitigating the impact of oceanic weather hazards on transoceanic flights
Alan Nierow, FAA, Washington, DC; and R. C. Showalter, F. R. Mosher, and T. Lindholm
Poster PDF (148.8 kB)
Transoceanic flights will increase significantly in the next decade. To efficiently manage this increased demand for capacity, it is possible that the separation minima normally used between aircraft transiting oceanic regions will be reduced both horizontally and vertically. However, in implementing reduced separation standards between aircraft, the hazards of convective weather over oceanic routes must be considered as aircraft have less airspace to maneuver. Because of these hazards, the improvement of current and forecast oceanic weather products is needed. It is also imperative that these products are made available to the operational decision-makers (controllers, traffic managers, dispatchers, and pilots).

Forecasters need to have an idea of where the areas of oceanic convective activity are located, but are hampered in that the only weather data consistently available is from satellite imagery. Very often, the imagery alone cannot reveal areas of convection that would impact aviation operations and influence routing/re-routing decisions. To aid this effort, the National Weather Service’s (NWS) Aviation Weather Center developed a current convective product that integrates an indicator of convective activity – lightning – with satellite imagery. The results were encouraging since this product has assisted NWS forecasters in generating Significant Meteorological Information (SIGMET) products for oceanic regions, deemed necessary as the Center’s forecasting responsibilities extend well beyond the range of land-based weather radars. Realizing the potential of this product for oceanic routing and hazardous weather avoidance, the Federal Aviation Administration (FAA) and NWS promoted an evaluation of the experimental product in 1999. The results demonstrated a potential for improved safety (e.g., avoiding areas of convective activity, turbulence) as well as an increase in efficiency (e.g., facilitate routing/re-routing resulting in smaller flight track deviations and reduced fuel costs).

Taking this product a step further, the FAA and NWS, along with the National Center of Atmospheric Research (NCAR) are developing new oceanic products that will discriminate between high clouds (cirrus) and actual thunderstorms. These products will contain algorithms that examine infrared satellite data to determine the existence of thunderstorm clouds. NCAR is utilizing current commercial communication and display capabilities to simultaneously present selected graphical displays of oceanic traffic (current and future positions) with an updated depiction of en route convection. This product has been made available to dispatchers and forecasters, and the depiction of convection relative to the flight path has been put on flight decks. An evaluation of this product is currently being performed, and preliminary results will be presented at the conference.

Future products will consist of not only a nowcast of convection, but also of a time-phased ‘snapshot’ which will eventually show a 6 hour forecast. These convective products will employ more sophisticated algorithms that use satellite imagery, model data, and ultimately lightning data. If these new products, and other products for turbulence and volcanic ash, become operational, they could play a significant role in supporting the demand for increased airspace capacity over oceanic regions without compromising safety. Furthermore, these new products could reduce non-coordinated diversions due to weather through better coordination based on greater situational awareness among oceanic controllers, dispatchers, and pilots. These products have the potential to greatly enhance the collaborative decision making process, especially over oceanic regions where surveillance and communications are not optimal.

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