WMOD00293

• Title: Summary of the NOAA/Utah Atmospheric Modification Program: 1990-1996
• Date: 9/1/1998
• State: UT
• Weather Modification - Doc Type: Report

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CONTENTS

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Page

1. Background and Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
'1.1 General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Objectives and Research Reported. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Problems with Statistical Evaluations ....................................... 2
1.4 Selection of Wasatch Plateau Experimental Area ..... . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.5 Experimental Field Projects. . . . .. . .. . '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.6 Report Structure. .............................. ..... ......... .-.......... 4

2. Availability of Supercooled Liquid Water. . . . . . . . . . . . . . . . . . . . . . . . . .'. . . . . . . . . . . . . . . 7
2.1 Background Information ................................................. 7
2.2 Field Observations of SL W ............................................... 8
2.3 Summary of SL W Findings ............................................... 9

3.

Transport and Dispersion of Ground-Released Seeding Agents and Tracer Gas ........... 11
3.1 Background Information ................................................. 11
3.2 Field Investigations of Transport and Dispersion .............................. 11
3.3 Analyses Based on Recent Laboratory StudJes ................................ 12
3.4 Seeding-Caused Snowfall Calculations ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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4. Results of Physical Cloud Seeding Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 Background Information ................................................. 17
4.2 Case Study Analyses .................................................... 17
4.3 Statistical Analysis of Pulsed Seeding Experiments .....................,...... 18

5. Numerical Modeling Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1 Background Information ................................................. 21
5.2 Model Applications to the Wasatch Plateau .................................. 21
5.3 Modeling of Generalized Weather Classes ................................... 22
5.4 Summary of Model Results ............................................... 22

6. Miscellaneous Associated Work. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . ... 25
6.1 Effect of type IT Statistical Errors on Experimental Duration ..................... 25
6.2 Runoff Increased Associated with Snowfall Enhancement . . . . . . . . . . . . . . . . . . . . . . . 25
6.3 New Instruments and Observational Approaches .............................. 26'

7. Summary and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.1 Overview ..... . . . . . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . : . . . . . . . . . . . . . . . . . . . .. 29

7.2 Key Physical Questions ....................;............................. 29
7."3 Key Physical Findings .......................................:........... 30
7.4 Summary of Findings and Recommendations. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .. 32
7.4.1 Recommendations to Improve AgI Seeding Effectiveness. . . . . . . .. . . . . . . . . 32
7,4.2 Additional Recommendations. . . . . . . . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33

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