A Performance Evaluation of the Juneau wind hazard alert system

This report presents a performance analysis of the Juneau Wind Hazard Alert System (JWHAS) system. The JWHAS system characteristics are compared to the current operational wind hazard information system, the Operations Specification (OPS Spec). The comparisons are done for a variety of hazard areas on the approach and departure paths from the Juneau airport. Additionally, system performance under three different wind regimes is considered. Overall, the JWHAS system outperforms the OPS Spec with respect to all measures. Typically, the JWHAS system shows a better ability to detect turbulence hazards, correctly doing so more than twice as often as the OPS Spec. Also, the OPS Spec has a very high false alarm rate compared to JWHAS. Accumulated over all hazard areas and all wind regimes, the OPS Spec alarms more than five times as often as the JWHAS system. The JWHAS identifies, but tends to underestimate the more severe turbulence hazards. When compared with Pilots’ Reports (PIREPs), the JWHAS system shows a good ability to discriminate between reports of no turbulence and reports of turbulence hazards that are moderate or severe.