F. Köpp

Remote Measurements of Boundary-Layer Wind Profiles Using a CW Doppler Lidar

Abstract We have demonstrated practical measurement of profiles of horizontal wind magnitude and direction to altitudes of 750 m by making radial velocity measurements with a Doppler lidar using conical scanning. Comparison with surface anemometers and with profiles measured by balloon sondes allows one to evaluate the consistency between lidar measurements and more conventional sensors. Overall we find a correlation coefficient of 0.83 and an rms difference of 1.3 m s−1 for magnitude and a correlation coefficient of 0.91 and an rms difference of 12° for direction when the lidar and sonde profiles are compared. The differences are not a result of lidar errors because comparisons of 20 s averages between the lidar and a sonic anemometer show a correlation coefficient of 0.98, an rms difference of 0.19 m s−1, and a long-term average difference of 0.05 m s−1 for a single component. Profile differences are attributable to horizontal inhomogeneity in the wind field and uncertainty inherent in balloon sondes. I...

A Joint Lidar Solar Radiometer Experiment

Abstract Remote sensing of the lower atmosphere by lidar yields profiles of the backscattering cross section along the optical path. These may be simply converted to give a qualitative picture of the distribution of atmospheric aerosol, but quantitative values can only be obtained if further information is available on aerosol properties such as refractive index and size distribution. In the experiments described below, use was made of a solar radiometer to give information on the second of these. This is then used to calculate an improved value for the ratio of backscattering to aerosol mass (β/m) for the interpretation of the lidar data. Comparison is made of the results of radiometer measurements, taken at a rural area outside Munich, with airborne lidar measurements of the tropospheric aerosol made in the same locality. Aerosol density profiles obtained in another flight made near Augsburg on 22 July 1977 show the presence of a heavy aerosol concentration over the city and the effects of the north win...

Remote sensing of mass fluxes of trace gases in the boundary layer

The combination of remote sensing methods like Doppler lidar and FTIR offers the possibility to determine mass fluxes of gases remotely. Doppler lidar measures the three-dimensional wind vector in the vicinity of diffuse sources or the velocity of air in a chimney plume if an industrial complex is monitored. FTIR is a multi-component remote sensing method for gas concentrations. The Fourier transformation of an interferogram of a Michelson interferometer within a FTIR system converts the recorded intensity (function of optical path length) to a spectral signal (function of wavenumber). Both information, velocity and concentration, give the mass fluxes of the tracer (gas). A first test was performed at Munich-North power station with FTIR and cw-Doppler lidar. Fluxes of CO2, CO, NO, and HC1 were determined. The results are in good agreement with the fluxes measured by in-situ instruments of the power station. The method can be used to control industrial complexes from an outside observation site.

Turbulent Energy Dissipation Rate Measurement Using Doppler Lidar

The experimental results for the temporal spectra of wind velocity measured by cw Doppler lidar at large probing volume are presented. The Doppler lidar method of measurement of turbulent kinetic energy diisipation rate eT, which is free of restriction on sounding range, is suggested. The example of restoration of height profile of eT from Doppler lidar measurements is presented.

Überwachung von Aerosolquellen und Bestimmung von Ausbreitungssparametern mit dem DFVLR-Minilidar

Vor zwei Jahren wurde auf der Laser 79 das DFVLR-Minilidar zum Einsatz fur Umweltschutzaufgaben vorgestellt [1]. Deshalb soll heute eine kurze Zusammenfassung der Systemeigenschaften genugen. Dafur soll umso ausfuhrlicher ausfallen die Prasentation der Mesergebnisse, mit Schwerpunkt auf zwei Mesreihen, die eine uber einem Industriegebiet und die andere uber Meeresoberflachen. Dabei werden die Moglichkeiten und die Grenzen dieser Mesmethode aufgezeigt.