A new field campaign for tropospheric turbulence studies with the MU radar and intensive insitu observations with RS92G Vaisala radiosondes

Soon after their conceptions, ST VHF radars have been used simultaneously with instrumented balloons for measuring atmospheric parameters. Intercomparisons improved our knowledge on the radar backscattering mechanisms at VHF which, in turn, provided some information on atmospheric dynamics and structures at various scales. Various methods were then developed for retrieving small-scale turbulence parameters from ST radars. However, the dominant sources and characteristics of the turbulent events detected by the ST radars in the troposphere are still poorly documented partly due to the lack of resolution of these instruments. The MU radar can be operated in range imaging (FII) mode so that a range resolution of several ten meters can be achieved at a time resolution of a few tens of seconds. For the first time, a field campaign was carried out in September 20011 for about three weeks with intensive balloon observations (59 RS92G Vaisala radiosondes launched every three hours mainly during night periods). The balloon data were devoted to the detection of turbulent events using an original processing method based on Thorpe analysis of potential temperature profiles (see the companion abstract by R. Wilson et al.). In addition, static stability and Richardson number profiles could be estimated in the vicinity or even within some turbulent layers. These data helped us to identify the nature of the instabilities detected by the MU radar and the background atmospheric conditions in which they occurred. Dynamical shear instabilities and convective instabilities at cloud edges will be particularly addressed in this work.