Convection, turbulence, generating cells and other fine scale structures within a Nor'easter: a first look at high resolution HIAPER Cloud Radar Observations

On February 2, 2015, the High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) cloud radar (HCR) was flown on its maiden research voyage on the NSF/NCAR Gulfstream V (GV) aircraft over a cyclone along the northeast coast of the United States. Six straight flight legs were flown over 7 hours between Washington DC and Bangor, Maine, crossing the rain snow line, and passing directly over Boston, which received nearly 12 inches of snow during the event. The HCR, a W-Band dual-polarimetric, Doppler research radar, recorded reflectivity, radial velocity, spectral width, and linear depolarization ratio. The 0.7° beam was pointed at nadir from a flight altitude of 12800 m (42,000 feet). At aircraft speeds varying between 200 m/s and 275 m/s (depending on which way it was traveling), the along track resolution ranged between 20 to 30 m. The range resolution was 19.2 m.

Remarkably detailed fine-scale structures invisible to standard scanning radar systems were found throughout the storm system, including cloud-top generating cells, upright elevated convection, layers of turbulence, complex structures across the melting level, gravity waves, boundary layer structures, and other complex features. Vertical velocities in these features ranged from 1-5 m/s, and many were on scales of 5 km or less. This talk will highlight these remarkable structures and examine their relationship to meteorological conditions in the storm.