Cloud Seeding Fluid

Votes: 4
Views: 268


The cloud seeding using silver iodide, salt solutions, etc. to induce or increase rain is a procedure that is used in many countries in order to help crop irrigation, forest fire combat, water dam replenishment, and even air pollution reduction.

Clouds are formed by tiny water or ice particles that form around solid dust, salt pollen etc. micro particles nuclei, whenever an airmass temperature drops below the so-called dew point and freezing point temperatures that are function of the air mass water vapor content.

This temperature drop may be caused by air raising due to convection, or to orographic effects on wind, and to encounters with a lower temperature airmass or water or soil surfaces, and also simply due to heat radiation to surroundings.

If not attaining a sufficient size and mass to start to fall these particles stay suspended in the atmosphere forming a cloud or finish to evaporate or sublimate back as water vapor extinguishing the cloud.

Rain or hail appear when these particles mix and grow to form rain drops or snow ice crystals due to air turbulence, static charge attraction, etc.

The cloud seeding seeks to accelerate this growing process providing high surface tension (silver iodide), or lower temperature (dry ice), or high hygroscopic (marine salt), or just heavier (pure water spray) nuclei.

Glycerin or glycerol (C3H8O3), besides being a highly hygroscopic and a high surface energy substance, their water solutions may have freezing points below zero Celsius degree and have even already been used as anti-freezing fluid in ICE engine radiators. Its solution with one third of water and two thirds of Glycerol has a -35 degree Celsius freezing point!

Then here it is proposed the use of water and glycerol, mixtures at ambient or even better below water freezing temperatures to be used in cloud seeding using aerial vehicles flying through convective clouds and or over stratified clouds in order to induce or increase rain as result of the catalyzing or coalescing effect of the seeded drops on cloud water or ice particles. Since water surface tension increases for decreasing temperatures, the cloud seeding with below zero temperatures water glycerol mixtures will largely amplify the rain drops or ice crystals formation inside a cloud.

Glycerol has low price being also a byproduct of bio diesel production. Its use as in food processing as humectant, and in skin cosmetics as hydrating agent prove its friendly properties to humans and so to ambient.

This represents a great advantage in comparison to the high negative ambient impact and equipment corrosion caused by silver iodide one of the most used rain making cloud seeding product.

The accompanying illustration shows typical cloud seeding operation to induce or improve artificial rain precipitation over crops, dams, and fires, by glycerol solution spraying (1) being done by airplanes (2), gliders (3), rockets (4), helicopters (5), above and inside convective clouds (6) and above stratified clouds (7).


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  • Name:
    Francisco Leme Galvao
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  • Francisco is inspired by:
    Nature and God
  • Software used for this entry:
    MS word and Acrobat Reader
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