A method of cloud seeding with use of ice-nucleating agents

Abstract

The present invention relates to a method of cloud seeding for the control of atmospheric precipitation (rainfall, snowfall, hail and fog) which uses as sowing agents, ice-nucleating of natural or plant or mineral origin.

Description

SUMMARY Cloud seeding method using natural ice nucleating agents 5 The present invention relates to a cloud seeding method for controlling atmospheric precipitation (rainfall, snowfall, hail and fog) which uses as seeding agents, ice nucleating agents of natural origin, either vegetable or mineral. DESCRIPTION CLOUD SEEDING METHOD USING NATURAL ICE NUCLEUSING AGENTS The technical field of the present invention relates to a cloud seeding method using natural ice nucleating agents. In nature, water can exist in solid (ice), liquid, or gaseous phases. The first appearance of a thermodynamically stable ice phase is called ice nucleation (Vali et al 2015). Freezing is a phase change process in which a liquid turns into a solid. The freezing process begins with ice nucleation, when an ice nucleus (nucleus) is formed, followed by crystallization, which is the further growth of the nucleus that attracts water molecules and arranges them in a crystal lattice. During crystallization, an amount of energy is released, the latent heat of fusion, which can be measured non-invasively using a thermal camera as described in the publication by Zaragotas et al (2016). Homogeneous ice nucleation is the process of ice nucleation that begins and continues without the presence of a foreign substance to facilitate the process, while heterogeneous ice nucleation is assisted by the presence of a foreign substance, usually referred to as an ice nucleating agent (Vali et al 2015). There are two different modes of heterogeneous ice nucleation. Deposition nucleation, which refers to supersaturated vapors settling on an ice nucleating agent, and freezing nucleation, which refers to the ice nucleation of a supercooled liquid (water that remains liquid at sub-zero temperatures) due to the presence of an ice nucleating agent. Freezing nucleation modes are further divided into immersion freezing, which is caused by an ice nucleating agent in supercooled water, conduct freezing, which is caused by an ice nucleating agent coming into contact with a supercooled liquid, and condensation freezing, which is caused by the formation of liquid on a cloud condensation nucleus. Cloud condensation nuclei are microscopic aerosol particles on the surfaces of which water vapor condenses. Warm natural nucleating agents are active at high, sub-zero, temperatures, between -1 °C and -8 °C. An nucleating agent can be a natural microorganism such as a nucleating bacterium, or a virus, or a fungus, or a lichen (e.g. US 5,169,783) or an organism such as a plant that possesses at least one nucleating gene, enabling it to produce an nucleating protein. Snomax (SNOMAX International, Englewood, CO) is a commercially available nucleating agent that has been used in cloud seeding experiments (Ward and Demott 1989, Woodley and Henderson 1990). The production of SNOMAX begins with fermentation of a bacterial culture of Pseudomonas syringae, then the ice nucleating proteins are separated from the rest of the culture using special filters and finally they undergo lyophilization.Despite the well-defined production process of SNOMAX, Polen et al (2016) reported on the unstable nature of the ice nucleating properties of SNOMAX. In addition to ice nucleating proteins, other organic components that can act as ice nucleating agents include, in particular, phospholipids, amino acids (Parungo et al 1967), carbohydrates and alcohols (UN 5,174,498). Ice nucleating agents can vary in size, for example microparticles, nanoparticles, powders, mineral particles and chemical compositions for example silver iodide, silver oxides, or aluminum oxide, due to their processing and / or composition. IceStart (Asymptote, Cambridge, UK) is a mineral ice nucleator produced by Asymptote, which holds several related patents relating to tectosilicate minerals and particularly feldspar, WO / 2014 / 091216, US Patent No. 10015958 and US Patent No. 0327538, or a formula containing tectosilicate minerals and ammonium salt to promote spontaneous ice nucleation WO / 2017 / 194954. Cloud seeding methods are generally used to control atmospheric precipitation, where in some cases we seek to increase it, as for example in cases of rainfall or snowfall, while in others we seek to suppress or limit it, as in hail and fog that limits visibility, e.g. on highways and airports. Cloud seeding methods are either hygroscopic or glaciogenic. Hygroscopic seeding methods involve the dispersion of salt aerosols by aircraft at the base of updrafts. This method has been used in updrafts with a warm base to induce precipitation and increase visibility in foggy conditions near airports (Haupt et al 2018). Glacial seeding can be applied by aircraft but also by ground-based generators and involves the dispersion of silver iodide aerosols, or dry ice, into a cloud containing supercooled droplets (Deshler et al 1990). It has been used in severe thunderstorms to protect against hail (by reducing the size of hailstones), over river basins to increase snowfall, in cumulo-nimbus and cumulus congestus clouds to induce precipitation, and in supercooled fog to increase visibility near airports. French et al 2018 demonstrated that glaciogenetic seeding in orographic clouds can lead to precipitation (snowfall) that would not otherwise fall in the target area. Silver iodide is the most common ice nucleator used in cloud seeding. Under certain conditions, it can affect living organisms in terrestrial and aquatic ecosystems (Fajardo et al 2016). Cloud seeding agents that can nucleate ice as effectively as silver iodide have been identified for some time, such as some crystalline organic substances (Parungo et al 1967) and certain bacteria (Levin et al 1987). Cloud seeding with silver iodide remains the most common method of cloud seeding. Its application requires the use of pyrotechnic cartridges that, upon combustion, release the ice nucleating agent of their composition, which are silver iodide crystals. Silver iodide crystals act as cloud condensation nuclei, the number of which is a function of temperature. The effects of silver iodide on human health and the environment remain controversial (Haupt et al 2018). Freezing by immersion is related to cloud formation (Murray, et al 2012). With the present invention, I propose to replace silver iodide and other common cloud seeding agents with natural cloud seeding agents, of plant or mineral origin, that have ice nucleation capacity, as demonstrated by a series of freezing by immersion experiments. Some of the cloud seeding agents we identified demonstrated extremely high ice nucleation capacity compared to the most effective, known ice nuclei. The proposed natural ice-snow method is suitable for existing technologies using airplanes or ground-based cannons and does not require the use of special structures such as, for example, cloud ionization, electrical precipitation, or laser-guided weather modification. It is more economical than silver iodide, which has been the standard cloud seeding technology for many years. The proposed method in a preferred embodiment uses biological seeding agents of plant origin (such as, for example, from the sea buckthorn plant) that are not toxic to humans and the living environment. In another preferred embodiment, the proposed method mimics natural precipitation phenomena (such as, for example, mineral dust present in the atmosphere). The following are non-limiting experiments for the invention. All experimental results presented below were generated using a technological platform and the appropriate methodology described in the publication of Zaragotas et al 2016. Experiment 1 Hail suppression -4 OOI ·.: 32 . -4 60 -4 60 -4 49 --4 Z i.' ·-.· · MI i·ii -4 G llgjggl llfS ojii MBiiil ea MM β -3 29ί -4 24 -4 22| -4 43 -3 84 IM® -4 34 -4 '9 : -3 9η -3 94 - .: : -4 5G -4 49 -4 65 -4 49 : ΙΙΙΙβι^ - 37ί -4 24 liSS -3 Sc 4 50 4 2 / | -3.94 -4 .4 70 4 54 IM—M -4 5y -3 63! 4 49 -4 73 . --4 -4 3η -3 98 111· -3 93 Billjiii Table 1A. Nucleation temperatures of 96 hail samples (above). _________<·______j_______ HALAZ1j ...............Tw..............I | Table 1B. Mean nucleation temperature (np), standard deviation (sd) and temperatures at which 50% of the samples froze (T50). As shown in Table 1A, the warmest ice core temperature measured for pea-sized hailstones collected on 18 / 4 / 2019 from Terpsithea, Larissa, was -3.29 °C (out of 96 measurements), while the average nucleation temperature was -4.30 °C (Table 1B). Therefore, in this specific case, an effective hail suppression program must include the use of ice cores warmer than -3.29 °C. Experiment 2 Comparative experiment (sea salts and potassium feldspar) K Feld 10-4 ............................... 0 48 K Feld 10-5 5 83 li·^^ K Feld 10-6 7 65 K Feld 10-7 -6 82 5 31 ·· K Feld 10-8 -9 0 6 44 -14 35 K Feld 10-9 -11 84 7 39 H20 Bottled THEOHI : -UM 1 13 16 40 Sea Salts 10-4 1 58 -14 34 Sea Salts 10-5 »»1 1 85 -14 89 Sea Salts 10-6 -12 70 241 -13 52 Sea Salts 10-7 -13 55 2 13 -15 14 Sea Salts 10-8 · 0 61 -14 93 Table 2. Nucleation temperatures of 96 samples of potassium feldspar (K-Feld), bottled water (H2O Bottled THEONI) (negative control) and sea salts (Sea salts) at five different concentrations. Mean nucleation temperature (np), standard deviation (sd) and temperatures at which 50% of the samples froze (T50). Sea salts are hygroscopic in nature as they absorb moisture from the air (Zieger et al 2017). Lahav and Rosenfeld (2003) reported seeding concentrated brine from the Dead Sea in an attempt to produce more cloud condensation nuclei (CCN) of desired size, at appropriate concentrations for long periods, and at lower cost than conventional seeding systems with hygroscopic cartridges. In experiment 2 we used an artificial mixture of sea salts (Sigma Aldrich, S9883) representative of the inorganic mass of most oceanic seawater which has already been used in cloud chamber experiments (Zieger et al 2017). Additionally, we compared the ice nucleation capacity of sea salts with that of potassium feldspar (K-Feldsar). It is known that not all whites are equally effective in their ice nucleation capacity (Harrison et al 2016). A sample has been identified that ice nucleates significantly higher than any other known and we selected it to use in our measurements as a reference sample (Table 2). The feldspar sample included in the above experiments clearly showed ice nucleation activity at warmer temperatures than the sea salt mixture at the same concentrations. Experiment 3 Comparative experiment (Aerosols of mineral and biological origin) It is known that various aerosols of mineral or biological origin can act as cloud condensation nuclei (Kumar et al 2011; Hiranuma et al 2019). The mineral samples used were quartz (Quarz) and illite (NX Illite) (NX illite is mentioned in many relevant atmospheric studies, such as Hiranuma et al 2019, Welti et al. 2009) while the biological samples used were fibrous cellulose (FC) and microcrystalline cellulose (MCC). H20 ! 54 7-: :.: : lour 0 lUrnL )42 kJUSrZ U □CMUrnL -12 10 ! 191 FC Π -9 27 i 0 97 -9 IS C MCC 0 SgMOmL -12 IL ! 18 - : Z ·' Hx0 5gM0mL -6 17 j 1 34 6 05 1 Tour 0 7g-'10mL »66 imImi Table 3 Nucleation temperatures of bottled water (negative control), tourmaline (Tour) at two concentrations of 0.46 and 0.7g / 10mL, quartz (Quarz), illite (NX Illite), fibrous cellulose (FC) and microcrystalline cellulose (MCC) at concentrations of 0.5g / 10mL. Mean nucleation temperature (pH), standard deviation (sd) and temperatures at which 50% of the samples froze (T50). As demonstrated by the results reported in Table 3, the ice nucleation activity of tourmaline, which belongs to the silicate minerals, was superior to that of the other samples. Experiment 4 Comparative experiment (Silver iodide and potassium feldspar) Figures 1 and 2 show the results obtained from two different freezing experiments carried out under the same conditions and concerning the freezing profile of 8 samples of silver iodide suspension in water (figure 1) and 6 samples of potassium feldspar suspension in water (figure 2). Both silver iodide and potassium feldspar do not dissolve satisfactorily in water. The ice nucleation activity of both samples decreased with decreasing concentration and the observed decrease was greater for potassium feldspar than for silver iodide. The same freezing profiles were also obtained at dilutions of 1 in 10, although the diluted potassium feldspar froze significantly less than the silver iodide. Therefore, in seeding applications, potassium feldspar is expected to be used in approximately ten times the amount of silver iodide. Experiment 5. Comparative experiment (Seahorse and Snomax) In the early 1990s, pilot cloud seeding experiments with Snomax proved successful (Ward and Demott 1989). In this experiment, we used Snomax as a positive control and compared its ice nucleation activity with that of a freeze-dried sample of sea buckthorn leaves. The ice nucleation activity of sea buckthorn, although lower of Snomax, was comparable to this. n.p. SD T50 Lyophilized Sea Buckthorn Leaf Powder I 0.45 -2.16 O.-g / mL____________________________________j -2.23 Snomax C,lg / mL 0 33 Table 4. Nucleation temperatures of 96 samples of lyophilized sea buckthorn leaf powder 0.1g / mL and Snomax. Mean nucleation temperature (m.p.), standard deviation (sd) and temperatures at which 50% of the samples froze (T50). The present inventive method can be used to suppress or limit hail, induce artificial precipitation, induce artificial snowfall, and to limit or eliminate fog. Bibliographic References Deshler, T., Reynolds, DW, & Huggins, AW (1990). Physical response of winter orographic clouds over the Sierra Nevada to airborne seeding using dry ice or silver iodide. Journal of Applied Meteorology, 29(4), 288-330. French, JR, Friedrich, K., Tessendorf, SA, Rauber, RM, Geerts, B., Rasmussen, RM, ... & Blestrud, DR (2018). Precipitation formation from orographic cloud seeding. Proceedings of the National Academy of Sciences, 115(6), 11681173. Harrison, A. D., Whale, T. F., Carpenter, M. A., Holden, M. A., Neve, L., O'Sullivan, D., ... & Murray, B. J. (2016). Not all feldspars are equal: a survey of ice nucleating properties across the feldspar group of minerals. Atmospheric Chemistry and Physics, 16(17), 10927-10940. Haupt, S. E., Kosovic, B., McIntosh, S. W., Chen, F., Miller, K., Shepherd, M., ... & Drobot, S. (2018). 100 years of Progress in Applied Meteorology Part III: Additional Applications. Meteorological Monographs. Hiranuma, N., Adachi, K., Bell, D. M., Belosi, F., Beydoun, H., Bhaduri, B., & Cory, Κ. M. (2019). A comprehensive characterization of ice nucleation by three different types of cellulose particles immersed in water. Atmospheric Chemistry and Physics, 19(7), 4823-4849. Kumar, P., Sokolik, I. N., & Nenes, A. (2011). Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals. Atmospheric Chemistry and Physics, 11 (7), 3527. Levin, Z., Yankofsky, S. A., Pardes, D., & Magal, N. (1987). Possible application of bacterial condensation freezing to artificial rainfall enhancement. Journal of climate and applied meteorology, 26(9), 1188-1197. Lahav, R., & Rosenfeld, D. (2003). Natural and artificial rain enhancement by sea spray. American meteorological society 83rd annual meeting, Long Beach (p. J.5.6). Murray, B.J.; O’Sullivan, D.; Atkinson, J.D.; Webb, M.E. (2012) Ice nucleation by particles immersed in supercooled cloud droplets. Chern. Soc. Rev. 41,6519-6554. Parungo, F., and J. Lodge Jr., (1967) Amino acids as ice nucleators. J. Atmos. Sci., 24, 274-277. Polen, M., Lawlis, E., & Sullivan, R. C. (2016). The unstable ice nucleation properties of Snomax® bacterial particles. Journal of Geophysical Research: Atmospheres, 121(19), 11-666. Vali, G., DeMott, P. J., Mohler, 0., & Whale, T. F. (2015). A proposal for ice nucleation terminology. Atmospheric Chemistry and Physics, 15(18), 10263-10270. Zaragotas, D., Liolios, Ν. T., & Anastassopoulos, E. (2016). Supercooling, ice nucleation and crystal growth: a systematic study in plant samples. Cryobiology, 72(3), 239-243. Zieger, P., Vaisanen, 0., Corbin, J. C., Partridge, D. G., Bastelberger, S., Mousavi-Fard, M., ... & Nenes, A. (2017). Revising the hygroscopicity of inorganic sea salt particles. Nature communications, 8, 15883. Ward, P. J., and P. J. DeMott (1989), Preliminary experimental evaluation of Snomax (TM) snow inducer, nucleus Pseudomonas syringae, as an artificial ice for weather modification, J. Weather Modif., 21(1), 9-13. Welti, A., Luond, F., Stetzer, 0., and Lohmann, U. (2009) Influence of particle size on the ice nucleating ability of mineral dusts. Atmos.Chern. Phys., 9, 6705-6715. Woodley, W.L., and T.J. Henderson (1990) Atmospheric Tests of an Organic Nucleant in a Supercooled Fog, J. Weather Mod., 22: pp. 127-132.

Claims

1. Cloud seeding method characterised in that the cloud seeding agents required for its application are natural ice nucleating agents, - either silicate minerals of the cyclosilicate mineral group such as tourmaline, - or a plant, or part thereof, belonging to the order Rosales, active in the temperature range between -5 °C and 0 °C.

2. Cloud seeding method according to claim 1, characterized in that the natural ice nucleating agents are silicate minerals of the group of tectosilicate minerals such as feldspar, nepheline, petalite, leucite, sodalite, cancrinite, scapolite, analkite and zeolite.

3. Cloud seeding method according to claim 1, characterized in that the plant, or part thereof, preferably belongs to the family Elaeagnaceae and the genus Hippophae.

4. Cloud seeding method according to claim 3, characterized in that the plant is Hippophae rhamnoides or a part thereof or a product thereof.

5. Cloud seeding method according to claims 1-4, characterized in that the natural ice nucleating agents are used in a mixture with other known ice nucleating agents such as alcohols and salts, in order to increase their effectiveness in cloud seeding.