Measurement of airborne radioactivity and its meteorological application. Part VII. Annual report, August 1, 1975--July 31, 1976

The studies of the stratospheric-tropospheric exchange were continued. The methods described in previous reports were retained. Continuous data of the cosmogenic nuclides /sup 7/Be, /sup 32/P, /sup 33/P and /sup 35/S and of fallout are given for the reporting period. A lidar system permitting remote sensing of stratospheric aerosol layers is described. Some examples of application demonstrate the effectiveness of an earlier described method for the forecasting of stratospheric intrusions. Fresh fallout from a Chinese nuclear weapon test could be identified by means of a GeLi-Gamma-Spectrometer. A harmonic analysis of the /sup 7/Be data resulted in frequencies which suggest a direct influence of solar rotation on the influx of /sup 7/Be and thus on the stratospheric-tropospheric exchange

Raman-shifted laser sources suitable for differential-absorption lidar measurements of ozone in the troposphere

Measurements have been performed at eight laboratories on Raman-shifted radiation from frequency-quadrupled Nd:YAG and KrF lasers. Each of these sources is a possible candidate for making differential-absorption lidar measurements of ozone in the free troposphere. The spectral purity, efficiency and divergence of the different sources are compared and explained using a simplified model of the Raman interaction. Particular attention has been given to the use of buffer gases to optimize the Raman gain and divergence. The experimental results show that the operating conditions required to optimize the output energy of each of these types of laser source can be quite different. In the case of the KrF laser, it has been shown that high energies can be generated at low active gas pressures, and that increasing the pressure increases the beam quality, but decreases the energy