Cloud boundary statistics during FIRE II

Abstract

An 8-mm wavelength radar, 3-mm wavelength radar, and 10.6-μm wavelength lidar operated side by side in vertically pointing mode during the First ISCCP Regional Experiment (FIRE II). Statistics on the location of cloud boundaries during the FIRE II experiment indicate that cloud bases tended to form at two discrete levels centered around 2.5 and 7.5 km, cirrus cloud tops formed most frequently at 9.5 km, and cloud thicknesses were usually 2 km or less. The atmosphere had the highest incidence of cloudiness at 8.5 km AGL, with a secondary maximum at an altitude of 3.5 km AGL. The incidence of cloudiness fell off rapidly below 8 and 11 km; there was also a distinct minimum in cloudiness at 2 km AGL.