Observations of vertical velocity over Illinois by the Flatland Radar

Abstract

A new VHF clear‐air Doppler radar has been constructed in very flat terrain near Urbana, Illinois. This radar, called the Flatland radar, as presently configured measures a profile of the vertical component of the wind velocity every 2.5 minutes. It is found that typical time variances of vertical velocity over this very flat terrain are similar to the small variances observed during “quiet” periods near mountains. The observed absence of extended periods of large variance supports the hypothesis that the “active” periods observed near mountains are mainly due to orographic effects. The absence of such effects at Flatland should facilitate the study of other meteorological processes. For example, in the case study presented here it is suggested that the vertical motions associated with large‐scale baroclinic storms are measurable by the Flatland radar.