Fitting Measurements of Thunderstorm Updraft Profiles to Model Profiles

Abstract

Twelve thunderstorm updrafts were analyzed in detail and a composite average derived. The updrafts were normalized in width and maximum intensity so they could he compared on the same scale. The composite average was compared with the Gaussian and the polynomial curves frequently used by modelers to describe some updraft characteristics. The composite average was also compared with an axially symmetric jet model. Favorable results were found in all three cases with good results in the case of the axially symmetric jet model. The relationship between updraft width and maximum vertical velocity is almost linear for smaller updrafts, but deviates from linear for the wider updrafts. It was found that a sensible temperature excess exists in the updrafts at the altitude where measurements were taken (5.0 to 6.2 km).