Development of Super Ensemble-based Aviation Turbulence Information and Guidance (SEATIG) and its Application to the Advanced Air Traffic Management (ATM)

Near-Cloud Turbulence (NCT) forecasts around various convective storms can help reduce occupant injuries from turbulence encounters. These forecasts can be used to either confirm or not confirm the presence of NCT resulting in improved guidance around those convective systems that can lead to Air Traffic Management (ATM) efficiency. In this study, the Super Ensemble-based Aviation Turbulence Information and Guidance (SEATIG) is developed and applied to the Contiguous United States (CONUS) during 7-9 September 2013. Turbulence forecasts from SEATIG can be complementary to convective impact information already used by some research ATM Decision Support Tools (DSTs) developed at NASA/ARC. The SEATIG combines an ensemble of component turbulence diagnostics (e.g., Eddy Dissipation Rate; EDR) used in the Graphic Turbulence Guidance (GTG; Sharman et al. 2006) and that of the time-lagged subgrid-scale Turbulent Kinetic Energy (TKE) values, derived from the High-Resolution Rapid Refresh (HRRR)-Weather Research and Forecast (WRF) model with 3-km horizontal grid spacing covering the entire CONUS. Probabilistic turbulence forecasts from SEATIG are more useful to take into account the small-scales and statistical nature of turbulence, the uncertainty in weather prediction models, and the demand for turbulence information in ATM DSTs. The HRRR-WRF model for this study is the same as the HRRR-WRF model used by the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL), except that this model integration is performed on the Pleiades supercomputer in NASA/ARC with initial and boundary conditions provided by the hourly-updated 13-km National Center for Environmental Prediction (NCEP)-Rapid Refresh (RAP) operational model outputs. In situ EDR measurements equipped in commercial aircraft are used to evaluate the SEATIG forecast exclusively for smooth and moderate-or-greater (MOG) intensity of NCT during the evaluation period. The sensitivity tests to the forecast lead-time and number of component diagnostics are also conducted to find the best combination of forecast lead-time and diagnostics used in SEATIG. On 7 Sep. 2012, convective clouds developed along the squall line over Illinois and Indiana ahead of an elongated cold front from the Great Lakes to Kansas. On 8-9 Sep. 2012, as upper-level trough deepened, clusters of thunderstorms along the eastward-moving cold front swept out the entire eastern and southern CONUS regions. This weather scenario is reasonably well captured by the HRRR-WRF model, and the SEATIG EDR forecasts were very consistent with the observed in situ EDR around the thunderstorms. Detailed results of this research will be presented in the conference.