Dr. Bruno Valentinov Kaul Profile

KEYWORDS: LIDAR, Scattering, Crystals, Light scattering, Particles, Clouds, Anisotropy, Atmospheric optics, Mass attenuation coefficient, Optical testing

Read Abstract +

Proceedings Article | 15 December 1995 Paper

Polarization structure of lidar returns from water droplet clouds

Bruno Kaul, Christian Werner, H. Herrmann

Proceedings Volume 2581, (1995) https://doi.org/10.1117/12.228506

KEYWORDS: LIDAR, Scattering, Clouds, Polarization, Multiple scattering, Laser scattering, Particles, Optical spheres, Backscatter, Spherical lenses

Read Abstract +

Proceedings Article | 15 December 1995 Paper

Discriminants in a backscatter lidar

Christian Werner, Bruno Kaul, Ulrich Oppel

Proceedings Volume 2581, (1995) https://doi.org/10.1117/12.228501

KEYWORDS: LIDAR, Backscatter, Polarization, Clouds, Multiple scattering, Atmospheric particles, Aerosols, Particles, Space operations, Receivers

Read Abstract +

Proceedings Article | 20 September 1995 Paper

Determination of the orientation of the ice crystals in a cloud

Bruno Kaul, Christian Werner, H. Herrmann

Proceedings Volume 2506, (1995) https://doi.org/10.1117/12.221063

KEYWORDS: LIDAR, Polarization, Particles, Crystals, Clouds, Beam propagation method, Crystallography, Backscatter, Scattering, Atmospheric optics

Read Abstract +

Theoretical grounds are given in this paper for two methods of determining preferred orientation of crystal particles in a cloud. The methods proposed in the paper enable one to do this in a much simpler way than it could be done when measuring full backscattering phase matrix. One of the methods proposed assumes that a polarization lidar can be rotated as a whole, while the second technique uses rotation of the polariztion plane of a linearly polarized sounding beam. Feasibility of the former technique is illustrated in the paper with the results of field experiments on sounding of a snowfall. Recent experimental studies of crystal clouds conducted with a polarization lidar capable of measuring backscattering phase matrices (BPM) have revealed the fact that preferred orientation of symmetry axes of particles in crystal clouds is very often observed to be in horizontal plane. This conclusion is drawn from the fact that off-diagonal elements of BPMs measured differ from zero. Using a model ensemble of crystal particles of axially symmetric plates and columns one can determine the direction of preferred orientation and the degree of particles orientation about this direction. For many practical reasons it is quite desirable to try to construct a technique for detecting situations in clouds under study when a preferred orientation of crystal particles occurs, which is more simple than that based on measurements of BPMs of clouds. Below we describe two possible versions of lidar measurements using a polarization lidar with a linearly polarized sounding radiation. Such a lidar can record two cross polarized components of lidar returns from scattering medium, i.e. two first Stokes parameters. One of the versions assumes that a lidar facility can be turned around the sounding beam axis as a whole, white in the second version we need to use a (lambda) /2 phase plate in the lidar transmitter to enable changes of sounding beam polarization. In order to make understanding of the techniques proposed easier, let us remind basic relationships for a polarization lidar sensing scheme.

Proceedings Article | 20 September 1995 Paper

Measurements of backscattering phase matrices of crystalline clouds with a lidar

Bruno Kaul, A. Kuznetsov, Ignatii Samokhvalov

Proceedings Volume 2506, (1995) https://doi.org/10.1117/12.221064

KEYWORDS: Beam propagation method, Particles, Atmospheric particles, Aerosols, Backscatter, Polarization, LIDAR, Crystals, Clouds, Scattering

Read Abstract +

Backscattering phase matrices (BPM) have been measured by a polarization lidar with controllable polarization of output laser radiation for measuring all the Stokes parameters at (lambda) equals 532 nm. The degree of orientation and the preferred orientation of particles are determined. To this end, the properties of BPM for the model of axisymmetric prolate particel (APP) ensemble are used. It has been suggested that scattering anisotropy of an aeosol layer, whose BPM is not described by the APP model, is caused by birefringence. In laser sensing of the atmosphere ensembles of aerosol particles being sounded are characterized by the backscattering coefficient. Very often, in addition to this parameter, the intensities of polarized and crosspolarized components of backscattered radiation are determined provided that lineraly polarized laser radiation is used. The ratio of these components is called depolarization and it is assumed a measure of the particle nonsphericity. Use of the above characteristics is based on the concept that atmospheric aerosols are ensembles of spherical or nonspherical randomly oriented particles. An experience of optical studies has shown that such a concept is quite justifiable for the majority of atmospheric aerosols. However, these exists quite a wide class of natural aerosols in the atmosphere, namely, the crystalline clouds, for which the lidar equation in scalar form is insufficient since such aerosol ensembles should be described with a backscattering phase matrix. Below we shall demonstrate this by an example. Of course, the necessity of using the BPM to describe such aerosols is, in certain sense, obvious because anomalous optical phenomena resulting from a pronounced anisotropy of light scattering by crystal clouds have been known long ago. Nevertheless, such phenomena are too rare and it is not a proiri clear how often essential deviations from the scalar approximation occur. Thus, the experimental material available for our analysis at present and partially described in references allow us to arrive at the conclusions that in 30-40 percent lidar observations of crystalline clouds either the backscattering coefficient depends on the direction of sounding radiation polarization or the polarization of scattered light becomes elliptical, or both these effects occur simultaneously.

Proceedings Article | 9 December 1994 Paper

Some peculiarities in sounding cirrus clouds from space

Bruno Kaul, Christian Werner

Proceedings Volume 2310, (1994) https://doi.org/10.1117/12.195860

KEYWORDS: Clouds, Particles, LIDAR, Backscatter, Atmospheric optics, Crystals, Earth's atmosphere, Polarization, Aerospace engineering, Space operations

Read Abstract +

Proceedings Article | 7 October 1994 Paper

Interpretation of the backscattering phase matrix of cirrus clouds

Bruno Kaul, Ignatii Samokhvalov, Olga Shefer

Proceedings Volume 2260, (1994) https://doi.org/10.1117/12.189219

KEYWORDS: Crystals, Backscatter, LIDAR, Atmospheric particles, Scattering, Clouds, Matrices, Atmospheric modeling, Atmospheric optics, Atmospheric physics

Read Abstract +

Showing 5 of 14 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years