WMOD00490

• Title: The Effects of Mountain Lee Waves on the Transport of Liquid Propane-Generated Ice Crystals
• Date: 9/9/1996
• Weather Modification - Doc Type: Report

1444 JOURNAL OF APPLIED METEOROLOGY VOLUME 35
TABLE 5. Sulfur hexaflouride plume characteristics from site 7 as observed by aircraft for ridge pass.
Plume
width
Dist. site 7 Max SF6 Avg SF6 Alt Temp Avg LWC Wind speed Wind direction
Date Pass (0) (Ian) (Ian) (ppt) (ppt) (m) (0C) (g m-3) (m S-I) ("1')
5 February 8 8 3.3 23.0 75 29 2524 -2.0 0.05 8 173
5 February 10 7 2.6 23.0 119 63 2523 -2,2 0.08 3 180
5 February 12 6 2.5 23.0 107 66 2654 -3.0 0.12 1 250
5 February 14 8 2.9 22.0 20 8 2809 -3.9 0.03 9 190
8 February 6 6 2.4 24.0 16 6 2661 -3.7 0.11 11 176
9 February 4 6 2.1 22.0 12 8 2662 -8.0 0.08 8 239
9 February 10 4 1.5 21.0 19 7 2527 -7.1 0.01 14 221
17 February 4 1.4 0.5 21.8 13 11 2619 -8.6 0.01 14 215
17 February 6 13 5.0 22.3 24 7 2618 -8.5 0.02 15 185
17 February 8 12 4.4 22.4 16 8 2621 -8.5 0.01 17 190
17 February 10 7 2.8 22.2 14 6 2619 -8.3 0.03 16 182
9 March 10 20 7.1 19.8 124 44 2342 4.3 0.00 6 206
9 March 12 23 7.9 19.9 110 38 2404 3.9 0.00 7 194
9 March 14 7 2.6 20.1 27 13 2421 3.5 0.00 6 207
17 March 2 8 2.8 21.2 25 13 2664 -0.7 0.07 22 222
17 March 6 30 11.8 22.3 25 8 2650 -1.4 0.11 21 227
19 March 6 6 2.2 20.2 22 11 2313 5.0 0.00 9 208
19 March 8 12 4.6 21.4 37 18 2487 3.2 0.00 11 218
Average 10 3.8 21.7 45 20 2562 -2.5 0.04 11 205

one racetrack circuit. Approximately eight complete
circuits could be completed during a routine mission.
Nine separate aircraft experiments were conducted.
Of these, four had both SF6 and propane released, while
five had SF6 only. Table 2 lists the dates and times of
each experiment and other relevant information, in-
cluding the location and amount of the maximum SF6
observed by the network of sequential samplers. If the
maximum SF6 observed by the aircraft was below the
nominal flight altitudes, the actual altitude of intercep-
tion is noted in column 9.

b. Plume analyses

The SF6 plume was. defined as being present from
the time when the concentration moved above the back-
ground to the time when the concentration fell at or
below background levels. Background levels varied
from flight to flight but were generally between 5 and
10 ppt. This methodology was patterned after the work
of Stith et al. ( 1986) and Super et al. (1989). For these
1993 experiments it was found that there was an II-s
lag between the time that SF6 was ingested into the

TABLE 6. Sulfur hexaflouride plume characteristics from site 9 as observed by aircraft for ridge pass.
Plume
width
Dist. site 9 Max SF6 Avg SF6 Alt Temp Avg LWC Wind speed Wind direction
Date Pass CO) (km) (Ian) (ppt) (ppt) (m) eC) (g m-3) (m S-I) ("T )
17 February 12 9 4.5 28.0 17 8 2614 -6.6 0.02 20 191
17 February 14 7 3.5 28.5 11 6 2616 -6.7 0.02 20 193
17 February 16 1 0.7 29.4 13 8 2622 -6.5 0.02 19 183
2 March 12 18 7.9 25.0 107 43 2146 3.8 0.00 7 240
2 March 13 30 11.8 21.7 120 49 2134 3.7 0.00 4 208
2 March 14 17 7.2 24.2 58 26 2135 3.7 0.00 9 232
2 March 15 30 13.6 25.1 136 40 2144 3.5 0.00 8 208
9 March 10 15 6.7 24.9 77 42 2359 4.3 0.00 9 211
9 March 12 15 6.7 24.8 144 73 2419 3.9 0.00 10 216
9 March 14 13 5.7 24.7 87 20 2477 3.3 0.00 10 217
16 March 6 30 14.3 27.1 28 9 2689 -0.4 0.20 17 241
17 March 2 5 2.4 26.2 15 5 2671 -0.7 0.17 23 225
17 March 6 8 3.5 26.4 15 7 2658 -1.2 0.09 23 231
19 March 8 10 4.4 26.4 15 5 2480 3.5 0.00 7 228
Average 15 6.6 25.9 60 24 2440 0.54 0.04 13 216