Three-Dimensional Air Circulation in a Squall Line from Airborne Dual-Beam Doppler Radar Data: A Test of Coplane Methodology Software

Abstract The detailed structure of a tropical squall line observed in central Florida was investigated from an airborne dual-beam Doppler radar, pointing respectively fore and aft. This allowed dual-Doppler observations from a straight flight path in a way similar to the coplane sampling technique proposed for two ground-based Doppler radars and for which the authors had developed an elaborate method in order to obtain a reliable wind estimation. The application of this analysis method to the airborne dual-beam radar observations is discussed, along with the basic requirements due to the specific airborne data sampling. The retrieved three-dimensional airflow structures within the convective part of the squall line are found to be quite consistent with those previously documented from ground-based radars, such as the convective-scale downdrafts sustaining a well-marked rear-to-front flow or the convective updrafts associated with the front-to-rear flow at mid-to-upper levels and that detrain into the rear...