Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Richard M. Schotland x
  • Refine by Access: All Content x
Clear All Modify Search
Richard M. Schotland

Abstract

An experimental study using lidar has been made of possible resonance scattering from water vapor at 694.38 nm. This radiation was not detectable. An upper bound for the differential backscatter resonance cross section, based upon experimental uncertainties, was found to be 6.7 times that of the Rayleigh cross section.

Full access
Richard M. Schotland
and
James E. Hartman

Abstract

The accuracy in the determination or the solar constant by means of the Langley method is strongly influenced by the spatial inhomogeneities of the atmospheric aerosol. Volcanos frequently inject aerosol into the upper troposphere and lower stratosphere. This paper evaluates the solar constant error that would occur if observations were taken throughout the plume of El Chichón observed by NASA aircraft in the fall of 1982 and the spring of 1983. A lidar method is suggested to minimize this error.

Full access
Kuo-Nan Liou
and
Richard M. Schotland

Abstract

A computational approach for the multiple backscattering from spherical cloud droplets for a collimated pulsed radar system has been developed, based on the geometry of the system. The radiative transfer relationships include a complete set of Stokes' parameters. The depolarization ratio of the multiple backscattering from a volume of spherically symmetrical and uniformly distributed water drops is obtained.

Calculations are performed for secondary backscattering from water clouds in terms of wavelength, cloud height, beam width and particle number density. It is found that the depolarization does not have a significant dependence on the wavelength in the visible and near visible, or on the distance between the target and receiver. However, the receiver beam width and particle number density significantly affect the depolarization as well as the returned power.

A small receiver beam width, on the order of 10−4 rad, is recommended for measurement of the depolarization due to ice crystals in clouds to avoid depolarization caused by multiple scattering from the liquid drops.

Full access
Richard M. Schotland
,
Kenneth Sassen
, and
Richard Stone

Abstract

Measurements by monostatic lidar have been performed in the laboratory and in the field of the linear depolarization ratios for hydrometeors. The depolarization ratios for water drops in the size range 10 to 2000 μ in diameter have been found to be less than 0.03. Similar measurements for ice crystal clouds and precipitation gave relatively high values. Laboratory studies of hydrometeors from young ice clouds of mixed type whose linear dimensions varied from 20–100 μ gave depolarization ratios of 0.38. Atmospheric observations of mixed crystals >350 μ in linear dimension gave depolarization ratios >0.8.

Full access