Boundary Layer Experiment - 1983 (BLX83)

PROJECT DESCRIPTION

The Boundary Layer Experiment - 1983 (BLX83) took place in Oklahoma during the summer of 1983. The objective of the experiment was to study the interaction of the boundary layer and fair-weather cumulus clouds. Special attention was paid to the study of the entrainment zone and the relationship between thermals and turbulent motions.

The dates of the experiment were between 25 May and 18 June 1983. Remote sensors, surface observations, a high-density array of balloon soundings, and aircraft measurements were used to measure the boundary layer during the experiment. Lidar and sodar were also used, as well as turbulence sensors. For more information on BLX83, the reader is referred to Stull and Eloranta (1984).

Good conditions for the experiment existed during the time period. Most of the time was spent measuring during the day time, in order to study the evolution of the convective boundary layer (CBL). The case day chosen for this study, 7 June 1983, was selected because on this day boundary layer cumuli formed and dissipated during the daylight hours.

CASE STUDY

On 7 June 1983, a high pressure system was centered directly over Oklahoma. Relatively calm winds were observed over the state. The high pressure system moved very slowly to the south; however, no significant advection occurred over the area.

Small cumulus clouds began to form at about 11:00 a.m. local time. Cumulus humilis was reported throughout the day, slowly reaching up to 30% coverage near 2:00 p.m. local. After this time, cloud coverage gradually decreased until 6:00 p.m. local time when nearly all clouds had dissipated.

References