Study of Divergence in the Boundary Layer Using Optical Propagation Techniques

Abstract

A wind-measuring system using three separate optical systems, each consisting of a 3 mW He-Ne 1aser and two photodiode receivers, forming an equilateral triangle 300 m on a side, has successfully measured the divergence over the area of the triangle, and the space-averaged horizontal wind vector. Good correlation was found between the flow into the triangle and occurrences of thermal plumes seen by an adjacent acoustic sounder. The flow into the triangle was proportional to the vertical velocity. During large convective activity, there was a certain periodicity in the occurrence of plumes.