WMOD00277

• Contract/Permit #: 14-06-D-6467
• Title: An Operational Adaptation Program for the Colorado River Basin
• Prepared By: Lewis O. Grant, Chappell, Crow, Mielke Jr., Rasmussen, Shobe, Stockwell, Wykstra
• Date: 10/1/1969
• State: CO
• Country: United States
• Weather Modification - Doc Type: Report

TABLE VI. --Estimate of scale changes during seeded periods with respect to
non-seeded periods as computed by three statistical methods. Scale changes
are shown as a function of a computed mean temperature advection in the
700-500 mb layer.
With Controls Without Controls
Total Sample Scale Scale
Stratification Sample Size Change Change
(C/12 hr) Size Utilized Method (%) P- Value (%) P- Value
Climax I
1. 4 to < 4. 4 S 25 S 25 NP1 >+200 .0031 >+200 .0044
NS 31 NS 31 NP2 +119 .047 >+200 .0119
(819, NS22) PAR +98 .0150
-1. 6 to <+1. 4 S 50 S 50 NP1 -18 .159 -48 .0150
NS 55 NS 55 NP2 -16 .159 -28 .085
(S34, NS43) PAR -13 .215
- 3. 6 to < - 1. 6 S 17 S 17 NP1 +67 .149 +73 . 154
NS 21 NS 21 NP2 +68 .179 +42 .206
(815, NS15) PAR +24 .201
4.4 to < 14. 0 and S 28 S 28 NPl -28 .082 -36 .056
-1 2. 0 to < - 3. 6 NS 24 NS 24 NP2 -17 .169 -29 .064
(S22, NS22) PAR -24 .109
Climax II
1. 4 to < 4. 4 S 13 S 13 NP1 >+- 200 .100 >+200 .051
NS 15 NS 15 NP2 >+-200 .159 >+200 .066
(S11, NS11) PAR +75 .159
-1. 6 to <+1. 4 S 26 S 26 NP1 +11 .305 -27 .215
NS 27 NS 27 NP2 -37 .261 -9 .382
(519, NS22) PAR +10 .367
- 3. 6 to < - 1. 6 S 10 S 10 NP1 +20 .288 +80 .169
NS 13 NS 13 NP2 +130 .082 +190 .0367
(:39, NS9) PAR +14 .330
4.4to<14.0 and S 12 S 12 NP1 -32 .087 -37 .0281
- 12. 0 to < - 3. 6 NS 11 NS 11 NP2 < -50 .0322 -31 .057
(::)1 0, NS11) PAR -37 .048
Wolf C reek Summit
O. 4 to < 5. 4 S 51 S 45 NP1 +48 . 121 +23 .261
NS 69 NS 60 NP2 +49 .142 +39 .192
(S24, NS36) PAR +62 .0197
-0.6 to <+0.4 S 54 S 48 NP1 -10 .401 +23 .245
NS 65 NS 60 NP2 +24 .212 +33 .147
(S26, NS37) PAR +19 .233
- 3. 6 to < - O. 6 S 47 S 42 NP1 +56 .0294 +63 .0495
NS 54 NS 53 NP2 +37 .064 +49 .0485
(S34, NS40) PAR +55 .0045
5.4 to < 10. 0 and S 12 S 12 NP1 -5 .319 <-50 .095
-10. 0 to < - 3. 6 NS 10 NS 8 NP2 <-50 .218 <-50 .075
(SlO, NS8) PAR +8 .421

. It might be expected that modification
:potential would increase with the speed of the.hori-
"zontal wind flow since higher upward speeds would be
[nduced if the flow was near normal to the mountain
barrier. However, whether this potential is realized
in increased snowfall on top the mountain is also
clependent upon 1he total time it takes for (1) the
artificial nuclei to reach and activate in the cloud

system, (2) the crystal to grow, and (3) the crystal to
settle to the mountain. Thus, the generator-target
spacing arid the horizontal extent of the orographic
cloud itself become important considerations in
whether the existing modification potential is realized
at the top of the mountain. The interaction between
the ice nuclei concentration and crystal size becomes
increasingly important when seeding the very high

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