Lidar Observations in Relation to the Atmospheric Winds Aloft

Abstract

Lidar (laser radar) observations of the visually clear troposphere between 4 and 14 km are compared with data from simultaneous rawinsonde ascents for the purpose of exploring possible relationships between lidar echoes and the atmospheric winds aloft. Because of its low intensity, the backscattered laser signal was monitored by means of a pulse-counting technique. The data indicate a relative increase in atmospheric backscatter with height underneath the level of maximum wind speed. The increase in backscatter represents an increase in the concentration of particulate matter. Since its level corresponds to the average altitude for dons clouds, it in believed that the increase in particle density detected by the lidar is due to advection and/or formation of ice crystals near the level of maximum wind. It is concluded that lidar-observed back-scatter profiles of the upper troposphere may be of value in inferring wind shear or layers of maximum wind speed, particularly in terms of extending information acquired by conventional means to other times.