Project STORMFURY Annual Report, 1970
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US.DEPARTMAENT OF THE NAVY ii_ S. DEPARTMENT OF COMMERCE I K. CtIAFEE, Searefary &L R. STANS, Secrelari toN.val Weoffher Servie Commaxnd National Oceanic and Atmospheric Administration ro.J. KOTSCH, Rear Admiral, USN, Comm.ander R. K. WHITE, Administraor COD CP, -a co MIAMI, FLORID MA 91 DISTRMIJ" S TAT Approved for public JDisribution Unlimifedrelease; STAi"ARO TITLE PAW 1. X..r x' '$~ 1.v .- gz~- ~Na~ . FOR TECHICAL REPORTS !IOAA-7108 3002 .I___________ ProJect" STO)RMFURY - Annual V'enort 1970 Pla 21971 7.A~~s1U.S. !Haval 'Weather Sber~ice Coazand and 8 tt~ kaz~~Rp ?i0'4 Nationg! Hi'rriene Rsegrh T.a.___________ 9. Pegiocioz sracizJawm Max ani Address 10. MV<ci UzLit *;0. U.S. Nlaval Weather Service Cc=. INOAAL Department of the Navy National Hurricane Rese (-.taix vo~. foWashington Navy Yard Laboratory GrnNS--93 SWashington, D.C. 20390 P.0., Box 8265I 7 Spow-Onar A~erc) %.= aW~ Address Uiversit-y or M4ia~i Bra 02h Typeei Irpoa a Peid Coral Gables, Fla. 33>121 COvege'! "Same and National Science Foundation Annual Report 1970 14 Spooamar~wi Agency Code 5. SUPPICzeo:2ZY Notes b16.Abstr.c-. Project STOR14PURY is a joint Department of ronnerce (?IOAA)- ,- epart':ent of Defense (Havy) p2rogram of scientific experiments designed %fo exr~1ore the structure arnd dynamics of tropical cyclones anud their - otential for modification. The Project which vas eorna~ly established -n 1962 has as its principal objective exnerimenta%;ion directed towards changing the hurricane's energy exchange by strategic seeding fror, aircraft with silver iodide crystals. The crystals are dispensed from pyrotechnic devices developed by the U.S. Navy. The hypothesis calls for a measurable decrease in the maximum wind velocities near the center of the storm. Navy and NOAA scientists and aircraft, supplemented by those of the U.S. Air Forces have cooperated in STOF?'Lrpy experimental operations since 1962 when the Project began. The 1970 hurricane season produced no tropical cyclones which were eligible for seeding experiments In spite of this, or perhaps because of it, the 1970 season was 17. Key WordsanD)ocument Analysis. l7a. Descriptors undoubtedy the most productive research period for Project STORMFURY to date. W'eather modification The results of these various research Iiurricaa~es activities are given. Tropical cyclones Cloud physics Pyrotechnis Cloud seeding Research proJects Evaluation 17b. ldcsnifier./Opcn-Endcd Terizs Project STORMFURY Annual Report, 1970 .7c. (:OSATI F~ield/Group sA1 4B 18. Distribution Statement 19. Sccuriry class (This 21. No. of Pages Con~ies available at either address Report) f 16 a~ea.iff in2 . ecufity Class (This 22. Ptice ape '- n n b lo ck Pa1 N 1. S Ij:jf FORM CFSTI.35 W-70) USCOMM.DC 65002-P70 U.S. DEPARTMENT OF THE NAVY J. H. CHAFEE, Secretary Noval Weatlher Seivice Command W. J. KOTSCH, Rear Admiral, USN, Commander o U. S. DEPARTMENT OF COMMERCE M. H. STANS, Secretory National Oceanic and Atmospheric Adminis!ration R. M. WHITE, Adminisiraor PROJECT STORMFURY ANNUAL REPORT 1970 J,,l - i~i'A'4E-~ i : MIAMI, FLORIDA .7 MAY 1971 Project STOPIFTUFY was establishea by a. Inte,-departmental agreement betw een the Departent of Commerce and the Department of Defense, signed juiy 30, 1962. Additional support has been provided by the Natinal Science Foundation under Grant NSF-G-17993. This report ;s .he ninth of a series of annual reports to be prepared by the Office of 'he Director itoaccordance with the Project STOR!iFURY int,.erdepatmental agreement. Additional copies of this report may be obtained from: U. S. Naval Weather Service Comnand Department of the N/avy Washington Navy Yard Washington, D. C. 20390 or National Hurrtcane Research Laboratory P. 0. Box 8265, Universty of Miami B-anch Coral Gables, Florida 33124. NOTICE The National Hurricane Research Laboratory and the Naval Weather Service Command, do not approve, recow;,iend, or endorse any proprietpry product or proprietary material mentioned in this publication. No reference shall be made 1'o either or- ganization or to this publication in any advertising or sales promotion which would indicate or imply that the National Hur- ricane Pesearch Laboratory or the Naval Weather Service Com- mand approves, recommends, or endorses any proprietary product or material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this publication. TABLE OF CONTENTS Page INTRODUCTION I HISTORY AND ORGANIZATJON 2 PROJECT STORMFURY ADVISORY PANEL 3 PUBLIC AFFAIRS 4 PYROTECHNIC DEVICES - SILVER IODIDE 4 AREAS OF OPERATIONS 5 PLANS FOR FIELD OPERATIONS - 1970 5 FIELD OPERATIONS 8 RESEARCH ACTIVITIES In OPERATIONAL AND RESEARCH DATA COLLECTION 12 OUTLOOK FOR 1971 13 REFERENCES AND SPECIAL REPORTS 14 APPENDIX A. Report On Meeting Of Project Advisory Panel A-1 APPENDIX B. A Hypothesis For Modification Of Hurricanes B-1 APPENDIX C. Hurricane Modeling At 'he National Hurricane Research Laboratory (1970) C-1 APPENDIX D. Summary Of Preliminary Results Fron: An Asymmetric Model Of The Tropical Cyclone D-1 APPENDIX E. Response of STORMFURY Cloudline Cumuli To AgI And AgINal Ice Nuclei From A Solution-Combustion Generator E-i APPENDIX F. Measurements Of Vertical Motion In The Eyewal'i Cloud Region Of Hurricane Debbie F-l APPENDIX G. An Estimate Of The Fraction Ice In Tropical Storms G-l APPENDIX H. Ice-Phase Modification Potential Of Cumulus Clouds In Hurricanes H-i APPENDIX I. Use Of Light Aircraft In STORMFURY Activities I-i APPFNDIX J. Use Of Echo Velocities To Evaluate Hurricane Modification Experiments J-1 Page Precipitationl AP PEi DitX V, A Swulmnary Of Padar IEcho Heights In HurricanesK- Project STORMiFURY Experimfenltal APPENIX L. NorthL- KPac:ificL-Eliigibility Toi The Western iv PROJECT STORMFURY ANIUAL REPORT - 1970 !UTRODI'CTION The apparently successful seeding operations on Hurri- cane Debbie in 1969 made it most urgent that similar experi- ments be carried out on a 1970 storm to provide further eval- uation of the effectiveness of the technique. The 1970 hurricane season, however, produced no tropical cyclones which were eligible for seeding experiments. In spite of this, or perhaps because of it, the 1970 season was undoubt- edly the most productive research period for Project STORMIFURY to date. Even though no eligible storm developed, the STORMFURY forces did operate together during dry-run exercises, cloud- line experiments, and on a data-gathering mission in Tropical Storm Dorothy. The dry-run exercises were conducted from the Naval Station Roosevelt Roads, Puerto Rico, on 21 through 24 July, and these were followed immediately by the cloudline exercises during the last 6 days of the month. The STORMFURY forces were again deployed to Puerto Rico when it appeared on 19 August that Tropical Storm Dorothy might develop into a hurricane and move into the Caribbean. Even if she did not intensify and become eligible for a modification experi- ment, she could still have provided a good storm for a STORM- FURY monitoring mission if her intensity remained suffi- ciently stable. On this basis, the STORMFURY forces moved to Puerto Rico on 20 August. Dorothy, however, started to weaken after crossing the island of Martinique, and the op- eration reverted to a data-gathering mission to provide badly needed information on a tropical wave. With the lack of eligible storms in 1970, the hurri- cane research efforts were intensified and carried out with- out operational interruptions. The results of these various research activities are extremely interesting particularly as they relate to future STORMFURY operations, and the more significant results are given in the Appendices to this re- port. Of special interest in this connection is Appendix B which details a new and better explanation for the apparent success of the 1969 "Debbie" experiments than was possible with the pre-existing hypothesis. The optimism generated by the "Debbie" work also re- sulted in increased emphasis being placed on the Project by the Government. In 1970 Project STORFURY was designated a National Pilot Project by the Interdepartmental Committee for Atmospheric Science (ICAS), and some additional STORMFURY funding was made available in the FY-1971 budget of the Department of Commerce. HISTORY AND ORSANIZATION Project STOR14FU.RY is a joint Department of Commerce (NOAA)-Department oF Defense (Navy) program of scientific ex- periments designed to explore the structure and dynamics of tropical cyclones and their potential for modification. The Project waich was formally established in 1962 has as its principal -bjective experimentation directed towards changing the hurricane's energy exchange by strategic se-ding from aircraft with silver iodide crystals. The crystals are dis- pensed from pyrotechnic devices developed by the U.S. Navy. The hypothesis calls for a measurable decrease in the maximum wind velocities near the center of the storm. Navy and HOAA scientists and aircraft, supplemented by those of the U.S. Air Force, have cooperated in STORMFURY experimental opera- tions since 1961 when the first informal agreement was pro- posed. TG date, the experiments conducted by the Project consist of: Hurricane Esther - seeded in 1961 - Single seeding Hurricane Beulah - seeded in 1963 - Single seeding Tropical Cumulus Cloud Seedings - 1963 Tropical Cumulus Cloud Seedings - 1965 Tropical Cloudline Seedings - 1968 Tropical Cloudline Seedings - 1969 Hurricane Debbie Seedings - 1969 - Multiple seeding Tropical Cloudline Seedings - 1970. Since 1962, only two hurricanes have been seeded!. The results of the Hurricane Debbie multiple seeding experiments conducted on 18 and 20 August 1969, were extremely encour- aging in that a decrease in the maximum wind velocity of the hurricane was observed on both days. Although by no means conclusive, these observations coupled with radar and other meteorological data strongly suggest that a modification to Hurricane Debbie was achieved.