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  • Author or Editor: N. L. Abshire x
  • Journal of Applied Meteorology and Climatology 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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C. M. R. Platt
,
N. L. Abshire
, and
G. T. McNice

Abstract

Lidar observations of a winter ice cloud in the zenith gave a very high reflection but a very small depolarization. When the lidar was tilted more than 0.5° away from the zenith, the reflection amplitude fell to 3% of it's zenith value, but the depolarization increased. The above properties proved unambiguously that reflection was occurring from the specular surfaces of horizontal crystals. These properties were used to estimate some cloud microphysical properties. At a selected time, the estimates gave a mean “diameter” of 74 μm for the horizontal faces, a crystal number density of 0.78 −1, and a maximum departure of the crystal axis from the horizontal of 0.5°. The fraction of the total crystal cross section which was specularly reflecting was estimated as unity.

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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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J. C. Kaimal
,
N. L. Abshire
,
R. B. Chadwick
,
M. T. Decker
,
W. H. Hooke
,
R. A. Kropfli
,
W. D. Neff
,
F. Pasqualucci
, and
P. H. Hildebrand

Abstract

Three in-situ and five remote sensing techniques for measuring the height of the daytime convective boundary layer were compared. There was, as a rule, good agreement between the different systems when the capping inversion was steep and well defined, and some variability when the stratification was not so sharply defined. Two indirect methods for estimating boundary-layer heights from the length scales of convective motions in the layer are also discussed.

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