TEXAS HIPLEX SUMMARY REPORT 1975·1980 Increasing Rainlall throuuh Research in weather Modification LP-184 TEXAS DEPARTMENT OF WATER RESOURCES 1983 TEXAS HIPLEX SUMMARY. REPORT, 1975-1980 By Robert F. Riggio William 0. Alexander Thomas J. Larkin George W. Bomar Texas Department of Water Resources Cooperators U.S. Bureau of Reclamation Texas Department of Water Resources Texas A&M University Texas Tech University Colorado River Municipal Water District LP-184 TEXAS DEPARTMENT OF WATER RESOURCES May 1983 TEXAS DEPARTMENT OF WATER RESOURCES Charles E. Nemir, Executive Director TEXAS WATER DEVELOPMENT BOARD Louis A. Beecher! Jr., Chairman ·George W. McCleskey, Vice Chairman Glen E. Roney Lonnie A. "Bo" Pilgrim W. 0. Bankston Louie Welch TEXAS WATER COMMISSION Felix McDonald, Chairman Lee B. M. Biggart, Commissioner John D. Stover, Commissioner Authorization for use or reproduction of any original material contained in this publication. i.e., not obtained from other sources, is freely granted. The Department would appreciate acknowledgement. Published and distributed by the Texas Department of Water Resources Pos t Office Box 13087 Austin, Texas 78711 ii TABLE OF CONTENTS Page FOREWORD.............................................................. ....... .. X ABSTRACT . .. .. .. .. .. .. .. xi 1. INTRODUCTION ................................................. ... .. ...... .. 1 1.1 Need for Research . ........................................ ............. ... 1 1.2 History of Weather Modification in Texas. ................... ... .... ........ 2 1.3 Recent Cloud Seeding Research in Texas . 3 1.3. 1 San Angelo Cumulus Project . 3 1.3.2 Colorado River Municipal Water District-Rain Augmentation Program . 4 1.3.2.1 District Ev aluation . 4 1.3.2 .2 Texas Department of Water Resources Sponsored Evaluation ... 5 1.3.3 Hail Suppression Activ ities in the Texas High Plains............ ... .... 6 1.4 High Plains Cooperative Program . 7 1.4. 1 Genera l.................................................... ... .. ... 7 1.4.2 Goals and Objectives . 7 1.4.3 HIPLEX Design . 8 2. TEXAS HIPLEX . 9 2.1 Statutory Responsibility .................................................... 9 2.2 Administration . 10 2.3 Texas HIPLEX Design . 10 2.4 Objectives . 11 2.4.1 Technical . 11 2.4.2 Delivery Techniques . 11 2.5 Project Area . 12 2.5.1 Terrain............................................ ................. 12 2.5.2 Climate . 12 2.5.3 Economy . 14 2.5.4 Water Resources and Needs . ........................................ 14 2.6 Field Operations........................................................... 14 2.6.1 General ......................... ................................... 14 2.6.2 Participants . .. 15 2.6.3 Instrumentation . 16 2.6.3.1 Radar . 16 2.6.3.2 Rawinsonde . 17 2.6.3.3 Surface Weather Stations . • . 17 2.6.3.4 Aircraft . 19 2.6.3.4. 1 Colorado River Municipal Water District.......... ....... 19 2.6.3.4.2 Meteorology Research, Inc. ............................. 21 2.6.3.4.3 Colorado International Corporation...................... 21 iii TABLE OF CONTENTS-Continued Page 2.6.3.4.4 Big Spring Aircraft ..................................... 23 2.6.3. 5 Raingages ................................................... 24 2.6.3.6 Satellite Laserfax ............................................ 26 2.6.4 Data Inventory ..............................., .............. ........ 26 2.6.5 Reports ........................................................... 26 2.6.6 Summary .......................................................... 27 3. TEXAS HIPLEX STUDIES ..................................................... 29 3.1 General .................................................................. 29 3.2 Meso a-scale Observations ................................................ 31 3.2.1 Satellite ............................................................ 31 3.2.2 Radar Echo Characteristics .......................................... 32 3.2.2. 1 Radar Echo Climatology ...................................... 32 3.2.2.2 Radar Echo Organization ..................................... 33 3.2.3 Precipitation ........................................................ 36 3.2.3.1 General ..................................................... 36 3.2.3.2 Rainfa ll Distribution .......................................... 36 3.2.3.3 Rainstorm Characteristics ..................................... 39 3.2.3.4 Results ...................................................•.. 51 3.3 Meso �-scale Observations ................................................ 53 3.3.1 Satellite ............................................................ 53 3.3.1.1 Albedo ...................................................... 53 3.3.1.2 Brightness Analysis .......................................... 53 3.3.1.3 Populations and Cloud Cover .................................. 54 3.3.1.4 Satellite Tracked Cloud Movement ............................. 54 3.3.1.5 Satellite De rived Cloud Tops Heights .......................... 55 3.3. 1.6 Satellite Analyses Compared with Radar and Raingage Data .... 55 3.3.1.7 Results ...................................................... 61 3.3.2 Radar .............................................................. 62 3.3.2.1 Radar Echo Climatology ...................................... 62 3.3.2.1.1 General ............................................... 62 3.3.2.1.2 Results ............................................... 63 3.3.2.2 Radar Echo Characteristics (A Climatological Approach) ......... 66 3.3.2.2.1 General ............................................... 66 3.3.2.2.2 Radar Echo Summary .................................. 66 3.3.2.2.3 Results ............................................... 71 3.3.2.3 Radar Echo Characteristics (A Case Study Approach) ........... 72 3.3.2.3.1 General ............................................... 72 3. 3. 2. 3. 2 Echo Interpretation .................................... 73 3.3.2.3.3 Echo Organization ..................................... 78 3.3.2.3.4 Results ............................................... 80 3.3.2.4 Skywater Radar Data Analyses ............................... 80 3.3.2.4. 1 Mesoscale Thermodynamic Profiles and Intensity of Convection ............................................ 80 3.3.2.4.2 A Mesoscale Case Study ............................... 81 3.3,2.4.3 Results .................................•............. 86 iv TABLE OF CONTENTS-Continued Page 3.3.3 Convective Cloud Environment ....................................... 87 3.3.3.1 General . 87 3.3.3.2 Methods of Meso {3-scale Data Analysis and Parameters Ev aluated ............................. ,...................... 88 3.3.3.2. 1 Gridding of Data....................................... 89 3.3.3.2.2 Surface Parameters .................................... 89 3.3.3.2.3 Upper Air Parameters.................................. 91 3.3.3.3 Results...................................................... 95 3.4 Microscale............................................................... 105 3.4. 1 Radar Structure . 105 3.4.2 Cloud Physics . 105 3.4.2. 1 The Microphysical Process................................... 107 3.4.2.2 Results..................................................... 113 3.4.3 A Massive Seed Case Study........................................ 119 3.5 Forecast Development . 120 3.5.1 Forecast Decision Tree . 120 3.5.1.1 Initial Stratification of Findings............................... 121 3.5.1.2 Refinement . 124 3.5.1.3 Performance................................................ 124 3.5.1.4 Conclusions . 126 3.5.2 Rainshower/Thunderstorm Forecast ing Model....................... 127 3.5.3 Severe Weather Studies . 127 3.6 Economic Studies . 129 4. PRELIMINARY FINDINGS AND CONCLUSIONS ................................ 131 4. 1 General . .. .. ... .......... .. .. ........ ...... ............... ......... 131 4.2 Convective Cloud Behavior................................................ 131 4.3 Precipitation . 133 4.4 Principa l Effects of Seeding . 134 4.5 Conclusions............................... ................................ 134 5. RECOMMENDATIONS ....................................................... 137 5.1 General . .. 137 5.2 Classification of Shower-Producing Clouds ............ �.................... 137 5.3 Experimental Unit . 138 5.4 Tentative Seeding Hypotheses . ............................................ 154 5.4.1 Seeding for Dynamic Effects of an Isolated Conv ectiv e Cell . 154 5.4.2 Seeding for Dynamic Effects of a Convectiv e Cluster . 155 5.4. 3 Seeding for Microphysical Effects................................... 156 5.5 Response Variables . 156 5.6 Future Work . 157 5.6.1 Meso {3 -scale Tasks . ... 157 5.6. 2 Microscale Tasks . 159 5.6.3 Supportive Tasks . 159 ACKNOWLEDGEMENTS......................................................... 16 1 REFERENCES ................................................................... 16 3 APPENDIX ...................................................................... 171 v TABLE OF CONTENTS-Continued Page TABLES 2. 1 Va riables measured and recorded by the District's P-Navajo in the 1979 Texas HIPLEX field program . 20 2.2 Variables measured and recorded by the District's P-Navajo in the 1980 Texas HIPLEX field program . 20 2.3 Va riables measured by MR I cloud physics package during the 1978-1979 Texas HIPLEX field program . 22 2.4 Variables measured by the CIC learjet during the 1979 Texas HIPLEX field season .................................................................... 23 2.5 Summary of Texas HIPLEX field operations