Under sponsorship from the NASA Aviation Safety Program (AvSP) and the FAA Aviation Weather
Research Program (AWR), we are researching methods to establish the character of turbulence, as it
impacts aviation safety. The goal is derive quantitative realistic three-dimensional + time fields of
atmospheric turbulence at scales aircraft, especially commercial aircraft, respond to, and use this to test and
evaluate turbulence remote and in-situ detection strategies as well as to derive aircraft response loadings.
Ideally, this data would be taken from field measurement campaigns, but unfortunately, such measurements
are scarce, and usually only provide single tracks, from which it is difficult to assess the full
three-dimensional character of the turbulence. Therefore, recourse has to be made to high resolution numerical
simulation of turbulence events. In collaboration with NCARís MMM division, we are developing
numerical simulations that resolve scales down to 100m. In particular, one thunderstorm simulation has
been produced at these scales, and others, including clear-air turbulence simulations will be undertaken
later this year. These are not idealized simulations, e.g., of rising hot bubbles, but are based on large scale
initializations that were known to produce severe turbulence encounters. Even though the resolution in
these models is very high, subgrid scale (unresolved) motions are still important, and evaluations of the
accuracy of current subgrid scale turbulence parameterizations are also part of this effort.
Research Lead: Bob Sharman