Because of its long lifetime below 45 km, ozone can deviate markedly from the concentration given by photochemical equilibrium considerations. Hence the ozone concentration can be used as an indicator of the motion of air masses, particularly in the stratosphere. The meteorological implications can be fully realized only by synoptic measurements, for which an artificial earth satellite is ideally suited. The method described employs the optical absorption properties of ozone in the ultraviolet region around 2900Å. A detector looking down towards the earth will receive solar ultraviolet scattered by the atmosphere which has been attenuated both by scattering out and by ozone absorption. Calculations are presented to illustrate the effective depth in the atmosphere to which the detector "sees," the effective depth being defined as the point above which 90 per cent of the contribution to the detector response is made. The sensitivity of the method to changes in the ozone concentration at various altitudes is also demonstrated.