Remote turbulence detection using ground-based doppler weather radar

Turbulence in and around clouds can pose a significant hazard to aviation, with convective turbulence identified as being responsible for a majority of all turbulence-related aircraft accidents. Regions of convective turbulence may be small (~1 km) and highly transient (~few minutes). Graphical Turbulence Guidance, an operational NWP-based turbulence forecast, produces hourly forecasts at a relatively coarse spatial resolution and does not explicitly forecast convective turbulence. High-resolution storm data from radar reflectivity or satellites may provide some indication of the likelihood of convective turbulence development, but cannot pinpoint its location or severity. The NCAR/NEXRAD Turbulence Detection Algorithm (NTDA) uses ground-based Doppler weather radar data to measure in-cloud turbulence, with a focus on identifying convective turbulence hazards. NTDA utilizes Level II data from the U.S. network of WSR-88Ds (NEXRADs) to produce real-time, rapid-update, three-dimensional mosaics of in-cloud turbulence. An NTDA product is also produced operationally in the Taiwan Advanced Operational Aviation Weather System using NEXRAD and Gematronik radar data. NTDA turbulence maps are suitable for tactical use by pilots and airline dispatchers and for providing input to comprehensive turbulence nowcasts. They also provide information about storm evolution useful for studying the relationship of turbulence production to thunderstorm dynamics and kinematics. This chapter motivates and describes the NTDA and discusses its performance.