The Application of RASS to Study the Marine Stratocumulus Boundary Layer

The vertical temperature structure of the boundary layer is of interest in the study of stratocumulus cloud formation and dissipation. During the ASTEX field observation period of June, 1992, Colorado State University operated a Radio Acoustic Sounding System (RASS) to take temperature measurements approximately every hour - three times the rate at which radiosondes were launched. The RASS temperature profiles agree favorably with those of coincident rawinsonde soundings and reveal changes in temperature patterns with greater temporal resolution. In some cases, data from strong temperature inversions were collected between sonde launchings thus providing a record of the evolution of the inversion region on a finer time scale.

There are several factors that limit the height coverage of a RASS including wind speed, wind and temperature gradients and turbulence. A mathematical model is used to simulate RASS in a variety of atmospheric conditions. The model serves in system development and in identifying those features of the boundary layer that are quantifiable using the RASS technique. Model results will be compared with actual RASS performance.