(note: This is part one of a report from Russia on their weather modification projects. Grammatical errors have been corrected from the original translation, as well as being lightly edited for readability-editor )
WEATHER MODIFICATION BY AIRCRAFT CLOUD SEEDING
Department of Cloud Physics and Weather Modification
Central Aerological Observatory
Rosgidromet, Russian Federation
An aircraft cloud seeding by ice-forming or hygroscopic agents is [the] basis of the technology.
The seeding is produced from aircraft equipped [with a] complex of onboard instrumentation for [the] measurement of aeronautical parameters and [the] characteristics of atmosphere and clouds necessary for decision making, fulfillment of seeding and assessment of its result, and also by the seeding means which include devices for dropping pyrotechnic generators of an aerosol of silver iodide (AgI) , liquid nitrogen generators of fine-dispersed ice particles and [with a] generator of hygroscopic particles.
The silver iodide aerosols, entered into a cloud by dropping pyrotechnical cartridges during the flight of an aircraft over the cloud top, is used as the main agent for cold-cloud seeding.
The seeding of the cold clouds which have reached definite stage of development, under condition of maintenance of optimal concentration of ice-forming aerosol particles provide realization of a dynamic seeding hypothesis, i.e. vertical growth of clouds, increase of this lateral dimensions, lifetime and, as a result, increase of amount of precipitations, falling out from cloud.
The nitrogen generators of crystallization nuclei provide forming of huge number of the fine-dispersed ice particles from the air water vapor at the expense of action of extremely low temperature[s] during the emitting into the atmosphere of a jet of steam-gaseous mixture of air and liquid nitrogen.
In this case the crystallization nuclei are being formed at the level of aircraft flight and [for] this reason the nitrogen generators are used, mainly, for seeding the relatively thin cloud layers.
The conceptual model for the warm cloud seeding by relatively large hydroscopic particles is based on acceleration the coalescence process by initiating the collision-coalescence process earlier in the life of the cloud.
It is postulated that by reducing the time required for the precipitation process to evolve with respect to the time available, rain efficiency will increase such that clouds that would not naturally rain will rain, and clouds that would naturally rain will rain more.