Abstract
Methods outlined indicate how an S-band radar with a broad vertical half-power beam width may be used profitably to obtain quantitative data on severe storms. Two Alberta hailstorms were studied using such a radar with gray-scale output; the 18 July 1964 storm was of a large, complex nature, while the 22 July 1964 storm produced a relatively small, isolated echo.
Contours of constant effective radar reflectivity, Ze, were integrated in the vertical to produce a single composite display of the “total radio reflectivity,” Zl, defined as the product of Ze and the beam depth. Largest values obtained were of the order of 105 mm6 m−2.
Equations were derived to calculate the liquid water content of the storms based on the assumption of constant Ze with height. About 50% of the total water aloft at the peak of the 18 July storm was contributed by only 10% of the horizontal area, i.e., the portion occupied by “core” (Ze > 105 mm6 m−2).
Although both storms displayed high concentrations of liquid water In small percentages of their total horizontal areas, it is shown that the smaller storm was far more “efficient,” in that it produced nearly half the liquid water in only one-fifth of the area.
Evidence was also found to suggest the presence of an “echo-free region.”
