Convective Boundary Layer Height Measurement with Wind Profilers and Comparison to Cloud Base

Abstract

The depth of the atmospheric boundary layer is of interest in several different areas, such as chemistry, pollutant studies, and global modeling. In this research the authors describe and compare several different measurements of boundary layer depth. First, the authors use the standard measurement from radiosondes to confirm the validity of wind-profiler measurements, which use humidity gradients to estimate the boundary layer depth. A method for obtaining meaningful cloud-base altitudes is then presented, and the results are compared to the wind-profiler boundary layer heights. The authors find good agreement between the different types of measurement but see that the profiler peak reflectivity is slightly raised above cloud base in the presence of boundary layer clouds. This may be due to increased humidity gradients at the top and edges of clouds or to increased turbulence within the cloud. Calculation of the boundary layer height using the bulk Richardson number is commonly used in computer models. Comparison with the authors? profiler measurements indicates that the calculation overestimates the height of the boundary layer and that the agreement between the methods is poor.