The evolution and structure of a "bow-echo-microburst' event. Part II: the bow echo

Abstract

A bow echo is a bow-shaped radar reflectivity pattern that is often accompanied by downbursts at the apex of the bulge. It appears that there are two types of bow echoes documented in the literature, the squall-line type (SLBE) and the single-cell type (CBE). It is not clear that these two types of bow echoes are dynamically similar. The elongated-shaped echo assumed a bowed shape below cloud base after the downdraft developed. The bow echo is associated with a cyclonic-anticyclonic vorticity couplet with maximum relative vorticity intensities of 5 × 10-3 and 4 × 10-3 s-1, respectively, at the 2.4-km height. This couplet does not exist prior to the initiation of the downdraft. -from Authors