Laser Radar Observations of Seasonal Changes in Atmospheric Density in the Mesosphere and Lower Thermosphere

Abstract

The results of two years of laser radar observations, of the mesosphere and lower thermosphere over Kingston, Jamaica (18.0N, 76.8W), are described. These show the existence of a clear annual variation in atmospheric density with a maximum occurring between January and March and an amplitude of a few percent. Superimposed on this is a longer term trend producing a decrease in the mean density over the period of observation. A comparison is made with the U. S. Standard Atmosphere Supplements for 15N and with an existing model for atmospheric density variations based on other measurement techniques.