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<br />SEPTEMBER 1982 J. B. SNIDER AND D. ROTTNER 1291
<br />TABLE 2. Average values of tl~mperature, liquid water content, cloud droplet concentration and mean diameter, and ice particle
<br />concentration as a function of size observed by the University of Wyoming cloud physics aircraft before and during three cloud seeding
<br />experiments on 3 March 1980 (after Stewart and Marwitz). !:;.t is the time rel;ative to the start of seeding with each agent.
<br /> LWC Ice particle concentration (L -1)
<br /> (g m-3)
<br />Seeding !:;.t Temperature Concentration jj
<br />agent (min) (oC) JW FSSP (cm-3) (~m)i (12.5-187.5 ~m) (25-800 ~m) (200-6400 ~m)
<br /> -4 -7.7 0.05 0.16 64 13 0 0 0.0
<br /> 13.4 -5.4 0.03 0.13 35 12 8 3 0.0
<br /> 20 -5.5 0.06 0.23 75 16 15 8 1.4
<br /> 26 -5.6 0.05 0.22 76 16 37 25 2.5
<br />AgI 31 -5.8 0.03 0.12 59 15 37 40 3.7
<br />37 -3.6 0.00 0.00 0 0 27 14 2.0
<br /> 44 -7.7 0.07 0.23 69 14 9 2 0.1
<br /> 48 -5.6 0.02 0.02 28 10 46 19 2.7
<br /> 53 -6.0 0.00 0.01 19 13 20 7 0.8
<br /> 57 -5.8 0.01 0.01 25 9 15 6 0.6
<br /> -8 -7.7 0.04 0.21 60 17 7 2 0.4
<br />CO2 4 -7.3 0.02 0.09 53 13 100 25 0.0
<br />8.5 -7.2 0.04 0.14 52 15 79 36 0.4
<br /> 14 -5.4 0.03 0.16 56 12 100 32 6.8
<br /> 0 -6.9 0.07 0.32 102 15 25 1 0.0
<br /> 8 -6.8 0.06 0.39 106 17 0 1 0.0
<br /> 12 -6.9 0.07 0.28 103 14 0 1 0.0
<br />None 15 -6.9 0.07 0.36 131 15 0 1 0.0
<br /> 20 -5.2 0.14 0.41 189 14 101 3 0.0
<br /> 24 -3.2 0.14 0.37 139 13 238 24 1.8
<br /> 29 -7.0 0.14 0.44 138 16 31 1 0.2
<br />
<br />Acknowledgments. The authors wish to thank Pro-
<br />fessor J. D. Marwitz and the crew of the University
<br />of Wyoming cloud physics aircraft for the in situ data
<br />reported herein. Mr. James A. Moore, Bureau of
<br />Reclamation site director, made the decision to per-
<br />form the seeding experiments. Dr. Arlen Huggins of
<br />Electronic Techniques, Inc., the operations director,
<br />coordinated the aircraft operations.
<br />
<br />REFERENCES
<br />
<br />Carley, W. J., L. E. Li1ie and F. S. Solheim, 1980; Sierra Coop-
<br />erative Pilot Project Field Season 1979-80. Final report, 65
<br />pp. [NTIS PB297065jAS].
<br />Guiraud, F. 0., J. Howard and D. C. Hogg, 1979: A dual-channel
<br />microwave radiometer for measurement of precipitable water
<br />vapor and liquid. IEEE Trans, Geosci, Electron., GEI7, 129-
<br />136.
<br />
<br />
<br />Gunn, K. L. S., and T. W. R. East, 1954: The microwave properties
<br />of precipitation particles. Quart. J. Roy. Meteor. Soc., 80, 522-
<br />545.
<br />Hogg, D. c., and T. S. Chu, 1975: The role of rain in satellite
<br />communications. Proc. IEEE,63, 1308-1331.
<br />Marwitz, J. D., R. E. Stewart and J. A. Moore, 1978: Dynamical
<br />and microphysical characteristics of winter storms over the
<br />Sien'a Nevada. Pre prints, Con! on Cloud Physics and Atmo-
<br />spheric Electricity, Issaquah, Amer. Meteor. Soc., 244-246.
<br />Snider, J, 8., H. M. Burdick and D. C. Hogg, 1980a: Cloud liquid
<br />measurement with a ground-based microwave instrument.
<br />Radio Sci., 15, 683-693.
<br />-, F. O. Guiraud and D. C. Hogg, 1980b: Comparison of cloud
<br />liquid content measured by two independent ground-based
<br />syst(:ms. J. Appl. Meteor., 19, 577-579.
<br />-, and D. C. Hogg, 1981: Ground-based radiometric obser-
<br />vations of cloud liquid in the Sierra Nevada. NOAA Tech.
<br />Memo., ERL WPL-72, 46 pp.
<br />Stewart, R. E., and J. D. Marwitz, 1982: Microphysical effects of
<br />seeding wintertime stratiform clouds near the Sierra Nevada
<br />Mountains. J, Appl. Meteor., 21, 874-880.
<br />
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