Detection of clear air turbulence using a diagnostic Richardson number tendency formulation

The performance of a diagnostic Richardson number tendency (DRT) formulation in detecting areas of relative "high risk" for encountering turbulence is discussed. The results are encouraging. An index for risk-ofencounter, c, is calculated which may be considered proportional to the probability of encountering turbulence at a given time and place. Using a data base of ten days during the 1976 turbulence survey, the mean of this index at points of pilot-documented encounters, ce, was significantly (at a level of significance >99.9%) greater than that of the background sample. The operational adaptability of the DRT formulation seems particularly attractive in that the input data can be supplied by the currently operational upper-air sounding network. An index based on c could be incorporated into flight-path optimization software. The resulting long-term favorable bias in fleet fuel consumption characteristics should lead to significant savings.