John A. Cooney

Atmospheric temperature profiles from lidar measurements of rotational Raman and elastic scattering.

Criteria for optimizing system parameters in the lidar measurement of atmospheric temperature profiles from simultaneous Raman and elastic returns by use of a three-channel system are discussed and summarized. It is shown that the filter constraints of earlier techniques are removed thereby eliminating the need for the high rejection capability of spectrometers in this type of measurement. Also, SNR is improved, and a greater freedom in the choice of optimum Raman filters is demonstrated.

Measurements of high resolution atmospheric water-vapor profiles by use of a solar blind Raman lidar

Presented here are preliminary results of measurements of atmospheric water-vapor profiles which were obtained by use of a solar blind Raman lidar. Interesting new features of the data gathered include high spatial resolution during daylight hours along with associated measurement errors.

Asymptotic behavior of the efficiencies in Mie scattering

We prove that a previous derivation of the scattering and extinction efficiencies for infinitely large absorbing spheres is incorrect, and leads to an erroneous limit for the scattering efficiency. We then derive an expression for the scattering efficiency limit from geometrical optics and that is valid when the refractive index has a small imaginary part.

Variable-wavelength solar-blind Raman lidar for remote measurement of atmospheric water-vapor concentration and temperature.

System definition and performance calculations are presented for a variable-wavelength solar-blind Raman lidar capable of remotely measuring profiles of atmospheric water-vapor concentration and temperature. A figure of merit is defined which is related to the wavelength dependent SNR. It is shown that the figure of merit for a particular output wavelength depends critically on the instantaneous total ozone overburden as well as the ozone content from the earths surface up to a maximum measurement altitude. Figures of merit for water-vapor and temperature profile measurements are presented. Best performance output wavelengths are given, and total output energies required to yield prespecified accuracies are computed.

Coherent anti-Stokes Raman scattering by droplets in the Mie size range

Results of coherent anti-Stokes Raman scattering from droplets in the Mie size range are presented. Scattering intensities are shown to reach values of 30 greater than an equivalent mass of material in bulk form.

Uses Of Raman Scattering For Remote Sensing Of Atmospheric Properties Of Meteorological Significance

A brief historical review of Raman scattering as applied to remote sensing in the atmosphere is given. Recent data on relevant cross sections are tabulated. System performance characteristics of some of the more important measurements of the Raman lidar are reviewed and compared with experimental results to date. Comparisons are made with alternative methods of atmospheric probing with particular emphasis on differential absorption lidar (DIAL) system performance. System performance capabilities are reassessed on the basis of the latest available hardware and a near-term outlook is projected.

Lidar measurements of rotational Raman and double scattering

The analysis of unusually strong Raman backscattering signals from clouds shows that such signals cannot be merely related to filter on-line leakage. Theoretical calculations of Raman double scattering in an atmosphere with high optical depth values are presented, and it is shown that the Raman multiple scattering effect is not negligible. The results of the calculations are in good agreement with the experimental data.

Measurement of the Ratio of the Vibrational Raman Cross Section for H2O Vapor to the Nitrogen Vibrational-Rotational Raman Band

Abstract In this letter, measurements of the ratio of the v1 Raman cross section for H2O vapor to the Nitrogen vibrational-rotational Raman band cross section are reported. These measurements, Involving as they do, the technique of laser atmospheric probing have cone about through methods not usually a part of the repertoire of the spectroscopist.

Lidar method of measurement of atmospheric extinction and ozone profiles

A description of a method of measurement of atmospheric extinction and of ozone profiles by use of the backscatter signal from a monostatic lidar is given. The central feature of the procedure involves a measurement of the ratio of the Raman backscatter returns of both the oxygen and nitrogen atmospheric content. Because the ratio of the number density of both species is known to high accuracy, the measurement itself becomes a measure of the ratio of two transmissions to altitude along with a ratio of the two system constants. The calibration measurement for determining the value of the ratio of the two system constants or electro-optical conversion constants is accomplished by a lidar measurement of identical atmospheric targets while at the same time interchanging the two optical filters in the two optical channels of the receiver. More details of the procedure are discussed. Factoring this calibrated value into the measured O2/N2 profile ratio provides a measured value of the ratio of the two transmissions. Or equivalently, it provides a measurement of the difference of the two extinction coefficients at the O2 and N2 Raman wavelengths as a function of the height.

Can Lidar Detect CAT? Part 2

In an earlier communication a brief outline was given of a method of detecting atmospheric clear air turbulence (CAT) by optical laser radar (lidar). In this letter more details of this method are presented. In addition, a second method, quite distinct from the first, is also presented. A simple but direct calculation on the ratio of scattering of electromagnetic radiation from atmospheric thermally caused optical index inhomogeneities (Rayleigh scatter component) to that from the refractive index inhomogeneities arising from atmospheric turbulence, was presented by Munich. In his conclusion, ho seemingly foreclosed on the use of optical radar in any simple way, as a means of detecting CAT. Indeed, ex-