Study of wind fields associated with subtropical squall lines using Envisat Synthetic Aperture Radar images and ground-based weather radar data

Abstract

Squall lines are lines of organized convective rain cells accompanied by wind shear and high wind gusts. They are usually studied by using ground-based weather radar. In this paper, three squall line events, which occurred over the South China Sea in 2006 and 2007, are investigated by using simultaneously acquired Synthetic Aperture Radar (SAR) images of the European Envisat satellite and ground-based Doppler weather radar data of the Hong Kong Observatory. Both radars yield wind fields: the SAR near-sea surface wind fields and the Doppler radar upper-air wind fields. Both wind fields are of high spatial resolution (sub-kilometre scale), making them useful to study fine-scale features in squall lines. Three squall lines events, each having distinct features, are presented. They show exemplarily the advantage of synergistic use of both SAR and ground-based weather radar in the study of squall lines.