CLOUD SEEDING

Abstract

Long-chain aliphatic alcohols are provided that induce ice nucleation at temperatures within the range of -8°C to 0.°C, from supercooled water present in small droplets and / or in the vapor state, and are useful for seeding supercooled clouds in order to enhance precipitation.

Description

TITLE CLOUD SEEDING INVENTOR POPOVITZ-BIRO RONIT GAVISH MICHAL LEISERWITZ LESLIE LAHAV MEIR PRIORITY ISRAEL PATENT APPLICATION FOR INDUSTRIAL INVENTION 15 JANUARY 1990 N. 93066 NOVEMBER 1990 N. 96512 Rome, 8 August 1994 THE MANAGER (GIOVANNA MORELLI) TO THE MINISTRY OF INDUSTRY, COMMERCE AND CRAFTS CENTRAL PATENT OFFICE - ROME PATENT APPLICATION FOR INDUSTRIAL INVENTION A. APPLICANT (O 1) Name L..................YEDARESEARCH AND DEVELOPMENT CO. LTD. RehOVOt Residence (IL) 2) Name L Residence L . . B. APPLICANT'S REPRESENTATIVE AT THE UCB , Raeh surname name L... ---------------y denomination study affiliation L. . le San Michele del Carso , 0004· , , Milan via I.....................................................................................................................1 n. I_1-LJ J cittì l--------ι see above C. ELECTIVE ADDRESS OF RECIPIENT L.........—------------------- ----------------------------via I________________________________________________________________________________________I n. I_LJ—LÌ city L-----------0. TITLE proposed class (sec / cl / scl) Li—LJ-J J Li IJ 1 CLOUD SEEDING_______________________________________ l ......... THE................... THE................. NTE AT UCB. Rae^eli Adele and others | r / t'Lvp_| DR. ING. A. RACHELI & C. E. DESIGNATED INVENTORS surname nomaLPOPOVITZ-BIRO Ronit2J LGAVISH Michal ___ yes L 4) L FORM A revenue stamp ____I NG J Lil J code LlJ J_1_I_LJ_l_1_1_LJ_1_1_lJ __________________________I LlJ J code LU__LJ_U_U_1_L_LJ_I_LLJ cod. tax I ι ι ι ι ι ι ι ι IIII Η II l .1 chap βίθιΙΔήΐ (evidence LlJ sister-in-law wife - — LEISEROWITZ Read it J cap LJ J .l_iJ (prov) LlJ. Bless Me f. PRIORITY nation or organization ι, L_…………….THE………………………. 2, L… . ....THE................................. G CENTER ABLE TO COLLECT MICROGANISMS, designation type of priority ………….JL ……JL D. INV. D. INV. H. SPECIAL NOTESNONE ………………. I ………………. I _____________________ ATTACHED DOCUMENTATION No. cs. Doc. 1| EJ ΓρκΟ'Ί n.pag. USJ Ooc. 2) £>: Cranium no. tav G4>J Ooc, 3) ELI Wl! Doc. 4) DJ XXK ) Doc. 5) Ql WJ Doc. 5) Pi L ms J Ooc. 7) PJ Γ RIS I 8.A «(deposit notes, total lire I___ request number ι 93066 96512 filing dates «denied S / R LLl / 91J / tL£P_£J Bl m / AAi / AWJ EJ summary with main drawing, description and claims (2 copies required) drawing (2 copies required if cited in the description) letter of assignment, powers of attorney or general power of attorney reference Inventor's designation priority documents with translation into Italian authorization for assignment deed full name of the applicant HUNDRED AND EIGHTY-ONE THOUSAND===_________ JDIE£IMILA==== fi bang brands for tire patent certificate I— COMPLETED ON Li J / LI J / A?L?1.J ​​SIGNATURE OEL(S) APPLICANT(S) L______£Β· IN CONTINUE Sl / NO ¢.9.] I---------------------------------------------- ---------------- (L A CERTIFIED COPY OF THIS APO IS REQUIRED Sl / NO PA ì J mandatory J mandatory PROVINCIAL OFFICE OF IND. COMM. ART. 01 ÌMILANO_______________________ MINUTES 0, FILING APPLICATION NUMBER IMI 01 A -4)00 71 The year nineteen hundred L................ROVeiìtUllO....................................................|, gjnrrìù(_ _________________I Reg.A fourteen 1. of the month of January, the applicant(s) indicated above, have submitted to me, the undersigned, this application, accompanied by additional documents for the granting of the patent reported above. I. MISCELLANEOUS NOTES BY THE AUTHORISATION OFFICER I The DEPOSITOR <L PROSPECTUS A SUMMARY OF THE INVENTION WITH MAIN DRAWING, DESCRIPTION AND CLAIM APPLICATION NUMBER L_MI-91-A-=€0071_____I REG A FILING DATE l_L-J / l_l-J / l .1 II .1 PATENT NUMBER L___________I ISSUE DATE Ld / 1 I l / l IIII D. TITLE CLOUD SEEDING___| THERE THERE L. SUMMARY Long-chain aliphatic alcohols are provided which induce ice nucleation at temperatures within the range of -8°C to 0.°C, from supercooled water present in small droplets and / or in the vapor state, and are useful for seeding supercooled clouds in order to increase precipitation. M. DRAWING MM / vem / 1154provv. DR. ING. A. RACHELI & C, Description of the invention entitled: 'CLOUD SEEDING' About the Company: SEE RESEARCH AND DEVELOPMENT CO. LTD. of Israeli nationality, with headquarters in Rehovot (Israel) - who appoints as agents, and domiciliaries, even severally between them, Dr. Eng. Adele Racheli, Dr. Ada Borella and Dr. Diana Domenighetti, of the DR. ING. A. RACHELI & C. Office - Milan - Viale San Michele del Karst, 4. Inventors: Deposited on: 14 GEfl. 1991 POPOVITZ-BIRO Ronit, GAVISH Mi.chal, LEISEROWITZ Leslie, LAHAV Meirj UPIC,À.* MILANO Patent Service N. : 000071 DESCRIPTION The invention relates to the enhancement of precipitation and the means to achieve this effect. The invention is based on the seeding of the atmosphere with finely divided, water-insoluble, long-chain alcohols that raise the threshold temperature for ice nucleation. Antifreeze molecules—both in the bloodstreams of polar fish and in car gas tanks—prevent ice from forming by interfering with crystal formation; a liquid containing antifreeze can only freeze if it has been cooled to a temperature lower than its normal freezing point. Nucleators have the opposite effect: they promote ice formation. Inducing or inhibiting crystal formation is - 3 DR. ING. A. RACHELI & C important in both biological systems (how frost bacteria destroy crops) and non-biological systems (how rain clouds can be seeded). Pure water can be supercooled to temperatures from -20°C to -40°C. The activation of ice nucleation, necessary for precipitation, has been used in induced rainfall by seeding silver iodide into clouds. Silver iodide is now used as an artificial rain nucleation system. It increases the ice nucleation temperature by about 5°C, resulting in an increase of about 20% in precipitation in a given region. There is an ongoing search for better materials that can be used as cloud seeding agents. Some crystalline organic substances (Perungo et al., J. Atmos. Sci, 24: 274 (1967) and some bacteria (Levin et al., J. Climate and Appi. Meteorology, 26: 1188 (1987)) were found to nucleate ice as efficiently as silver iodide. It was now found that the spreading of alcohol monolayers! insoluble in water on water droplets, raises the freezing point of these significantly and reduces supercooling to a greater extent than the means used up to now for the formation of ice by nucleation. The present invention relates to the use of long-chain aliphatic alcohols of the formula CH + 011 or η 2n 1 HC-(CH) -R-(CH ) -OH 3 2 m 2 p - 4 DR. ING. A. RACHELI & C. where n > 14 and m + p > 14 and R is an unsaturated radical, a heteroatom, a carbonyl or an oxycarbonyl, to induce ice nucleation at temperatures within the range of -8°C to 0°C, from supercooled water present in droplets and / or in the vapor state. In particular, the invention relates to the use of such alcohols for cloud seeding to enhance precipitation. In a preferred embodiment, alcohols of the formula CH + OH are used when n is an odd number. Preferably, n is 27, η 2n 1 ~ 29 or 31 when ice nucleation is induced at temperatures from about -2.7°C to about 0°C. The most preferred alcohol is CH OH. 63 The invention further relates to a method of enhancing precipitation comprising seeding supercooled clouds with an alcohol as defined above. The alcohols of the invention can have both antifreeze and nucleating effects, depending on whether they mix in the solution or form surface monolayers. At the monolayer-solution interface, hexagonal ice crystals and hexagonal OH groups from the alcohol clearly fit together well; this favors ice formation and the growth of oriented crystals. The freezing point elevation was sensitive to the length of the alcohol chain, the number (even or odd) of carbon atoms in the chain, and the percentage of the liquid droplet surface that was covered by the nucleating alcohol. The ice nucleation temperature elevation achieved by the monolayer systems of the invention is about 10°C compared to only 5°C for silver iodide. The alcohols DR. ING. A. RACHELI & C. - 5 amphiphiles are also biodegradable, are cheaper and must be used in very small quantities. In the invention experiments, freezing point measurements were performed on two water drops of the same size (ranging from 10 to 40 µl) placed on a cooling plate in a purged envelope with cooled nitrogen gas. One drop was completely covered with a monolayer of amphiphilic chain alcohol and the other with a reference material, such as the corresponding long-chain fatty acid. In this way, the effect of all factors responsible for inducing nucleation, other than a difference in structural comparison, was eliminated. The samples were cooled at a rate of -1°C / min. The temperature of the drops was measured using a thermocouple. The melting point of ice was used for its calibration. The freezing points were observed. using a light microscope. The freezing temperatures were determined in comparative experiments performed simultaneously on two different materials. The different amphiphiles can be divided into three categories: (a) the reference materials have the lowest ice nucleation temperatures; (b) aliphatic alcohols show an order of nucleation efficiency that increases with increasing chain length, and (c) alcohols with larger surface areas per molecule are insufficient nucleators. EXAMPLES Drops of water (10 µl) were placed on a cooled plate under an optical microscope. One of the drops was covered with DR. ING. A. RACHELI & C. 0.5 µL of the alcohol in chloroform. The second drop was similarly coated with an amphiphilic reference material. The solvent was evaporated. The system was purged with nitrogen and cooled at a rate of approximately 1°C / min. The observed cooling points for both drops were determined. The cooling point of the drop coated with the reference material was at a lower temperature. The results are shown in Table 1. The results of freezing point measurements showed that aliphatic-chain alcohols nucleate ice at higher temperatures, and with greater reproducibility, than analogous carboxylic acids. The freezing points of pure water droplets, for comparison, ranged from -20°C to -25°C. It is surprising that the freezing point is so sensitive to the length and parity of the alcohol chain CH + OH. The freezing point curve η 2n 1 for the n-odd series increases asymptotically with chain length, approaching 0°C for n-31. The n-even series behaves differently; the freezing point curve reaches a plateau of about -8°C for n in the range from 22 to 30. This trend suggests that just before ice nucleation, the orientation of the OH groups in the even and odd analogues are not the same, the former having a closer structural fit to the ice lattice structure. In accordance with the invention, a suitable preparation of long-chain aliphatic alcohols, e.g., an emulsion, is brought to DR. ING. A. RACHELI & C. Contact with supercooled clouds to induce nucleation and increase precipitation. The dynamic cloud seeding method, whereby material is seeded in increased concentrations onto the supercooled upper part of the cloud, is suitable for this purpose. The material can be dispersed in clouds in a finely dispersed form. It can be applied as a mist released from a high altitude. TABLE 1 Examples or Ale voi / Point of cotlEdlnmenl.o Molars t è Hifcrlmento / Point of óóflgelamdrlto 1 C3 <Hes.0H / -7,5i0,5°C G,6xl0~'lM Ca.JIr^COOnZ-15, 011,6°C 2 Ca iHcaOKZ-0,510,5°C ΰ,ΰχΙΟ-'Ή c9j»nB!.cooH / -i5f βίΐ,δ’ο 3 Ca3IU3<)H / ~5,311,4°C 4,0x10-*H CaolUxCOOHZ-17,311 jO°C 4 CasF]3!> OH / '-1,4il,0oC 5,0xl0~*M Canili-,vCOOHZ~12,011,5°C 5 Ca,1Is»OH / -2,?.i 0,5°C 5,2x10**14 Ca^lU oCOOIlZ-15,311,5 °C fi CaBHSxOH / -3,4±l,OeC 5,0x10**11 CasCOOllZ-15,311,5°C 7 Caa|l

Claims

CLAIMS 1. The use of long-chain aliphatic alcohols of the formula H,C-(CIL ) -R-(Cii) -OH 3 2 m 2 p DR. ING.A . RACHELI & C. where n>14em+p) 14 and R is an unsaturated radical, a heteroatom, carbonyl or oxycarbonyl, to induce ice nucleation at temperatures within the range of -8°C to 0°C, from supercooled water present in droplets and / or in the vapor state.

2. Use according to claim 1 for cloud seeding to increase precipitation.

3. Use according to claim 1 or 2 of alcohols of the formula CH + OH where n is an odd number, η 2n 1 4. Use according to claim 3 where n is 27, 29 or 31.

5. A method for inducing ice nucleation at temperatures within the range -8°C to 0°C, from supercooled water present in droplets and / or in the vapor state, comprising contacting the supercooled water with a long-chain aliphatic alcohol of the formula: C II + ,0H o η 2n 1 H,C-(CH ) -R-(CH ) -OH 3 2 m 2 p where n > 14 and m + p > 14 and R is an unsaturated radical, a heteroatom, carbonyl or oxycarbonyl.

6. A method according to claim 5 for enhancing precipitation comprising seeding supercooled clouds with said alcohol.

7. Method for enhancing precipitation involving seeding supercooled clouds with an alcohol of the formula C Hn + OH or η 2n 1 H„C-(CH„) -R-(CI1 ) -OH 3 2 m 2 p where n > 14 and m+ p > 14 and R is an unsaturated radical, a heteroatom, - 9 DR. ING. A. RACHELI & C carbonyl or oxycarbonyl.

8. Method according to claim 7 where the alcohol has the formula CH + OH and n is an odd number, η 2n 1 9. Method according to claim 8 where n is 27, 29 or 31.

10. Method according to claim 9 wherein the alcohol is