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<br />34
<br />
<br />Table 5.-Parameter u.U vs. Diffusion Tests and Storm Periods.
<br />
<br />PARK RANGE ATMOSPHERIC WATER RESOURCES PROGRAM
<br />
<br />Diffusion <T.U Analysis <T,U
<br />test Date period Date
<br />1 February 2, . . . , , , ' , , , . ' . , .41 1 February 5, . , . , , , ' . , , , ' , , 0,69
<br />2 February 3,.",.,...",.. .44 2 February 7 ' , . , , , , , , ' , , , , ' 0,15
<br />3 February IS. ",.".""., ,21 3 February 10, , . ' , , , , ' , , , , , 1.:37
<br />4 February 22, , , , , . , , , . , , . , ,S2 4 February 14, ............ . O,:{S
<br />5 March 11. . . , , , . , . . , . , , . , ' ,09 5 February 22, ............ . 1. 57
<br />6 March 25, , . , , , , , , . . , , , , . , .71 6 February 24, , , , . , , , ' , , , ' 0,93
<br />7 April S.....,..,..,.""., .27 7 February 27 , , , . , , ' , . , , , ' . 2,12
<br /> S February 2S, , ' , . , , . , , , , , , 1. 70
<br /> 9 March 9-10"", , . , , , , . , , . 0.13
<br /> 10 March 13. , . , , ' . , . , , . , , ' , , 0,44
<br /> 11 March 14, , , . , , , , . , , , , , , , . 1.24
<br /> 12 March 16-17, , , , , ' , , , ' , , , ' MSG
<br /> 13 March IS".,. , , ' , , ' , , , , . ' 1. 90
<br /> 14 March 21. , , , , ' . , , ' , . , , . , , 1.42
<br /> 15 March ,22, ' , , . , ' , , , ' , , , , ' , I.S9
<br /> 16 March 24"" , , , , , , , , , , ' , , 0,92
<br /> 17 March 27, , , . , ' , , , , ' , , , , ' , 1.48
<br /> 18 April 5"""".""""" 2,36
<br /> 19 April 7.,.""""",.",. MSG
<br /> 20 April 9"."",.""."". 0,78
<br /> 21 April 10, ' . , , . , , . , , . , , , , , , 1.06
<br /> 22 April 12, . , . , , . , , , , ' , , ... . MSG
<br /> 23 April 17. . , , , , . , , , ' , , , , . , , MSG
<br /> 24 April 23, , ' . , . , , . , , , , , , , . , MSG
<br /> 25 April 25, , , . , , , . . , , . ' , , , ' . MSG
<br /> 26 April 27, , , . , , , . , , , , , , , . ' . MSG
<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 storms 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 />
<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 nuclei count be-
<br />tween storms with nuclei counter. Determine rela-
<br />tive abundance of supercooled water drops and arti-
<br />ficial nuclei in replicas.
<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 Lodge 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 />2 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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