Developing a Global Turbulence and Convection Nowcast and Forecast System

Turbulence is widely recognized as the leading cause of injuries to flight attendants and passengers on commercial air carriers. Turbulence encounters frequently occur in oceanic and remote regions where ground-based observations are sparse, making hazard characterization more difficult, and where current World Area Forecast System products provide only low temporal and spatial resolution depictions of potential hazards. This paper describes a new effort to develop a global diagnosis and forecast system that will augment and enhance international turbulence and convective SIGMETs and provide authoritative global turbulence data for the NextGen 4-D database. This fully automated system, modeled on the FAA’s Graphical Turbulence Guidance (GTG) and GTG Nowcast systems, will provide 3-D probabilistic turbulence nowcasts and forecasts globally above 10,000 feet MSL for 0-36 hour lead times, comprehensively addressing clear-air turbulence (CAT), mountain wave turbulence (MWT), and convectively-induced turbulence (CIT). The system will employ NCEP Global Forecast System model output and data from NASA and other national and international satellite assets to produce the CAT and MWT diagnoses based on both model-based turbulence diagnostics and satellite-based turbulence detection algorithms. The convective nowcast methodology makes use of GFS data and operational satellite data from GOES, Meteosat and MTSAT, and will be tuned and verified using data from NASA’s TRMM, Cloudsat and MODIS instruments. The convective nowcasts will be coupled with the GFS environmental information to assess the near-term likelihood of CIT. This paper presents an overview of the system elements and initial algorithm development results. Future work will perform additional development and verification using comparisons with automated quantitative in situ turbulence reports, AIREPs and AMDAR data. A real-time demonstration including a webbased display and cockpit uplinks is also planned.

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