A Probabilistic Forecast Algorithm of Nonconvective Turbulence over the Tibetan Plateau

Abstract

The development of upper-level turbulence forecast algorithms is important for enhancing flight safety. Seventeen nonconvective turbulence indices were calculated over the Tibetan Plateau for August from 2012–2021 with ERA5 reanalysis data. The thresholds for these turbulence indices were reclassified by using the percentile method based on the Richardson number. The reclassified thresholds were found to be more reasonable than the empirical thresholds. A turbulence probability index was used to aggregate the 17 turbulence indices without requiring observational data. The validity of the turbulence probability index was preliminarily confirmed by comparing it with turbulence events. Further research revealed that the turbulence probability index exhibited interannual fluctuation.

Keywords

• upper-level turbulence
• probabilistic forecast algorithm
• turbulence index
• Tibetan Plateau