Application of surface-reported weather type in the Terminal Area Icing Diagnosis and Forecasting Capability

The Terminal Area Icing Weather Information for NextGen (TAIWIN) icing diagnosis and forecasting capability ingests and uniquely applies weather information from radar, satellite, numerical weather prediction models, and surface observations to provide information on icing conditions within the terminal airspace. However, best practices for the application of surface observations, particularly weather type, are still being investigated. Several studies led by the NSF National Center for Atmospheric Research have concluded that the indication of a weather type in a Meteorological Aerodrome Report (METAR) does not guarantee it is physically present. These weather reporting issues can be particularly problematic at airports that experience less traffic and do not have a contract weather observer on site 24/7 to augment METARs.

During the winter of 2022, a DMT fog monitor and a Parsivel² disdrometer were deployed to the Syracuse, NY airport to supplement instrumentation for a series of research flights conducted during the TAIWIN Demonstration Program. This purpose of this program was to collect data in icing conditions to support the development and evaluation of the TAIWIN icing diagnosis and forecasting capability. Drop size measurements and concentrations from these ground-based instruments were analyzed to provide direct evidence of obscurations and precipitation types and were compared to METAR weather types. The results of this study, as well as avenues to apply or modify METAR observations to better represent the expected conditions to the TAIWIN icing diagnosis and forecasting capability, will be discussed.

This research is in response to requirements and funding by the FAA. The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.