WMOD00412

• Title: Final Report on Utah Cloud Seeding Experimentation Using Propane During the 2003/04 Winter
• Date: 3/1/2005
• State: UT
• Weather Modification - Doc Type: Report

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CONTENTS - continued

12.

HAS temperature partition: Warmer half of EUs, -7.5 to -0.90C.................................................... 57

13.

HAS direction partition <= 270 deg combined with icing detection anywhere, or at the TAR but
not necessarily at the other sites.. ........... .......... .................. ......................... .......... .......................... 59

14.

HAS direction partition <= 270 deg combined with HAS warm temperature partition, from -7.5 to

-0.90C . ........... .... ................. ........... ..................... ............ ...................... .......... ....................., ... ....... 60

15. HAS direction partition <= 270 deg combined with GNO SWE less than or equal to 0.05 inch.. 61

16.

HAS direction partition <= 270 deg combined with slower HAS wind speed partition................ 62

17.

Tests using GSO as a control. ......................................................................................................... 66

18.

Mean double ratios and median double ratios for EUs in the HAS median direction partition of

<= 270.......... ................. ............. ............. ....... ........... .............................. ........... ........ ............... ...... 67

19.

Summary of HAS and TAR observations during 3 EU periods of21 December 2003, each 40 min

in duration ............ ............................................................ ............... ............. ................ .............. ...........72

20.

Summary of TAR 2D-C ice crystal concentrations and estimated precipitation rates by size ranges
from 1216 to 1246 MST during the seeded period on 21 December 2003........................................79

21.

Distribution of mean IPCs for 21 seeded and 22 nonseeded EUs with available 2D-C obs.ervations
and HAS median wind directions between 169 to 270 deg........................................................... 82

22.

Summary of Mammoth-Cottonwood snow pillow SWE for four listed months and the 4-month

total ............................................................................................................................... .................. 85

23. Summary of daily SWE observations for 60 days with significant snowfall................................. 92

24.

Summary of gauge GTR hourly observations during 60 days with significant snowfall at two or

more gauges.. ............. ...................... ........... ...... .................... ................... .......... ............ ......... ........ 96

Figures

Figure

Page

I.

Map of experimental area for the Utah 2003-2004 propane seeding experiment............................ 4

2.

Vertical cross section through HAS and GTR snowing relative locations of instrumented sites.... 5

3.

An example ofSF6 tracer gas plume detection by the passage of an instrumented van on 21

February 1994 ............... .......... ............... ................... ................ ......... .................... ....... ................ 10

4.

Plot of southern SF6 plume edges south of the TAR versus HAS wind direction .......................11

5.

Plot of northern SF6 plume edges north and south of the TAR versus HAS wind direction ........ 12

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