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  • Author or Editor: V. E. Derr x
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N. L. Abshire
,
R. L. Schwiesow
, and
V. E. Derr

Abstract

Significant Doppler lidar returns have been observed from snow and rain. This demonstrates the feasibility of measuring velocity and range of hydrometeors with 10.6-μm wavelength CO2 laser lidar.

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V. E. Derr
,
N. L. Abshire
,
R. E. Cupp
, and
G. T. McNice

Abstract

The observed depolarization of polarized lidar signals scattered from virga and a source cloud may be interpreted to show that the source cloud is largely glaciated, and the virga is composed of ice crystals not randomly oriented. The orientation of the ice crystals in the virga, generally possible only in a nonturbulent atmosphere, is demonstrated by depolarization ratios greater than 1. The cloud processes suggested by this observation are in agreement with other independent observations.

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V. E. Derr
,
R. S. Stone
,
H. P. Hanson
, and
L. S. Fedor

Abstract

Surface measurements of solar flux and total integrated liquid-water content, radiosonde data, and infrared satellite images are analyzed in conjunction with radiative transfer calculations to derive an empirical parameterization for the shortwave transmissivity of continental stratiform water clouds. The data were collected near Denver, Colorado, over a period of six years. Seventeen days on which uniform stratiform clouds persisted over the observing site were selected for detailed analysis, and form the basis for deriving the parameterization. A mulitiple reflection radiative transfer model is employed to estimate stratus cloud transmissivity in terms of the measurable liquid-water path (LWP). A nonlinear fit of estimated transmissivities to the corresponding observations of LWP yields close agreement with a previous, more complicated parameterization. The derived expression for cloud transmissivity is used to predict mean daily surface fluxes for 61 days during which periods of stratiform clouds were observed over the Denver area. A comparison between predicted and measured fluxes shows agreement to within ±4%, with best agreement for clouds of moderate optical thickness. Potential sources of error are identified with sensitivity studies.

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R. L. Schwiesow
,
R. E. Cupp
,
V. E. Derr
,
E. W. Barrett
,
R. F. Pueschel
, and
P. C. Sinclair

Abstract

Using an airborne lidar, we have measured atmospheric aerosol backscatter coefficients (differential backscatter cross section per unit volume) for 10.6 μm wavelength laser radiation as a function of height to 5200 m for a number of meteorological conditions over the United States high plains. Airborne in situ samplers measured the particle size distribution at the same time and altitude as the lidar measured backscatter. One backscatter coefficient profile at 10.6 μm was compared with a 0.694 μm lidar backscatter profile as well as with the particle size distribution profile. The average infrared backscatter coefficient ranged from ∼8 × 10−9 m−1 sr−1 at the surface to 1 × 10−10 sr−1 at 5200 m altitude.

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atmospheric sciences and problems of society

A series of statements on the relevance of the scientific and technological areas of AMS STAC Committees to national and international problems

Earl G. Droessler
,
John S. Perry
,
Lance F. Bosart
,
Robert F. Dale
,
Walter A. Lyons
,
Robert E. Dickinson
,
Floyd C. Elder
,
Harold W. Baynton
,
J. A. Weinman
,
V. E. Derr
, and
William R. Bandeen
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