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<br />
<br />34
<br />
<br />PARK RANGE ATMOSPHERIC WATER RESOURCES PROGRAM
<br />
<br />"
<br />
<br />Table 5.-Parameter u.U vs. Diffusion Testsand Stonn Periods.
<br />
<br />Diffusion
<br />test
<br />
<br />Date
<br />
<br />(f.U
<br />
<br />February 2. , . . . . . . . . . . . . .
<br />February 3. . . . . . . . . . . . . . .
<br />February 18. . . . . . . . . . . . . .
<br />February 22. . " . , . . . . . . . . .
<br />March 11. . . . . . . . . . . . . . . . .
<br />March 25.. .. . . . . . . . . . . . . .
<br />
<br />April 8. . . . . . . . . . . . . . . . . . .
<br />
<br />.41
<br />.44
<br />.21
<br />,82
<br />.09
<br />.71
<br />.27
<br />
<br />1
<br />2
<br />3
<br />4
<br />5
<br />6
<br />7
<br />
<br />\~
<br />I':
<br />I.
<br />i
<br />;~
<br />tt
<br />.If
<br />
<br />. site, Emerald Mountain, can be used for most
<br />storms. During storm periods, the 11,000 foot ASL
<br />wind must be measured periodically to determine
<br />that nucleation will be effective on the target area.
<br />With a single nucleating generator site, it is desira-
<br />ble to install calibration equipment at the site and
<br />make frequent calibrations of generator output dur-
<br />ing storm periods. Auxiliary nucleating sites should
<br />be ready at all times to nucleate stonns with an
<br />11,000 foot ASL wind between 1800 and 2400, in
<br />order not to lose data or nucleating opportunities.
<br />
<br />Was There a Deficiency of
<br />Natural Freezing Nuclei?
<br />Method.-Determine whether supercooled water
<br />drops existed over the target prior to artificial nuclei
<br />release by taking snowcrystal replicas. Determine
<br />whether the abundance of supercooled water drops
<br />changed during and after nuclei release by taking
<br />replicas. Monitor natural freezing nucld count be-
<br />tween storms with nuclei counter. Determine rela-
<br />tive abundance of supercooled wat,er drops and arti-
<br />ficial nuclei in replicas.
<br />
<br />Analysis
<br />period
<br />
<br />Date
<br />
<br />1
<br />2
<br />3
<br />4
<br />5
<br />6
<br />7
<br />8
<br />9
<br />10
<br />11
<br />12
<br />13
<br />14
<br />15
<br />16
<br />17
<br />18
<br />19
<br />20
<br />21
<br />22
<br />23
<br />24
<br />25
<br />26
<br />
<br />February 5. . . . . . . . . . . . . . .
<br />February 7. . . . . . , . . , . . . . .
<br />February 10. .. , . . , . , . . . . .
<br />February 14, . . . . . . . . . . . , .
<br />February 22. . . . . , . . . , . . . .
<br />February 24. . . . . . . . , . , . . .
<br />February 27 , . . . . . . . . . . . . .
<br />February 28, , . . . . . . . . . . . .
<br />March 9-10...............
<br />March 13, . . . . . . . . . . . . , . . ,
<br />March 14. .... . . . . . . . . , . . ,
<br />March 16-17..,..........,
<br />March 18. ,... . . . . , . . . . . . .
<br />March 21. . . . . . . . . . . . . . . . .
<br />March 22.. .. . . . . . . , . . . .. .
<br />March 24. , . . . . . . . . . . . . . . .
<br />March 27. . . . . . . . . . . , . , . . .
<br />April 5.. . . . . . . . , . . . . . . . . .
<br />April 7. . . , , , . . . . . . . . . . . . .
<br />April 9.. . . . , , . . . . . . . . . .. .
<br />April 10.. . , . .. . . . . . . . .. . ,
<br />April 12.. . . . . . . . . , . . . . , . .
<br />April 17. . . , . . . . . . . . . . . . . ,
<br />April 23.. . . . . . . . . . .. .. . . .
<br />April 25. . . . . . . . . . . . . . . . . .
<br />
<br />April 27. . . . . . . . . . . . . . . . . .
<br />
<br />(f.U
<br />
<br />0.69
<br />0.15
<br />1.37
<br />0.38
<br />1.57
<br />0.93
<br />2,12
<br />1.70
<br />0.13
<br />0.44
<br />1.24
<br />MSG
<br />1.90
<br />1.42
<br />1.89
<br />0.92
<br />1.48
<br />2.36
<br />MSG
<br />0,78
<br />1.06
<br />MSG
<br />MSG
<br />MSG
<br />MSG
<br />MSG
<br />
<br />Data.- Visual observation of rime ice on trees in
<br />the target area during winter season. Natural
<br />freezing nuclei count at Valley View Lodge 1 Febru-
<br />ary to 1 May 1965; figures 47a, 47b and 47c. Re-
<br />plicas taken at Valley View Lodge between January
<br />and May 1965. Neutron activation analysis of arti-
<br />ficial snow samples.
<br />Analysis.-During ridge runs in the early winter
<br />months, we observed rime ice on the trees-indica-
<br />tive of frozen supercooled water drops. If this is a
<br />consistent phenomenon, it indicates a deficiency in
<br />natural freezing nuclei. The nuclei count at Valley
<br />View Lodg~ generally shows a reduction during
<br />storm periods. This could be due to (1) natural
<br />freezing nuclei being used in forming snowcrystals,
<br />and (2) natural freezing nuclei being scavenged by
<br />already-formed snowcrystals. Available data2 indi-
<br />cate that the' nucleus of a snowcrystal is always by
<br />far the largest solid particle present. Therefore,
<br />
<br />· Kumai, M., 1961: "Snow Crystals and the Identification of
<br />Nuclei in the Northern United States of America," Journal
<br />of Meteorology, Vol. 18, No.2, pp. 139-150.
<br />
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