The cloud seeding programs in Iran include the airborne method for the cold clouds, and the airplanes are equipped such that they are able to seed the clouds from the top and inside. The material used in Iran cloud seeding programs, is silver iodide for seeding the convective clouds and liquid nitrogen for seeding the stratiform clouds. Silver iodide acts as ice nuclei and with the initiation of the Bergeron’s process, leading to the production and enhancement of the ice crystals and the subsequent speed up of the precipitation process. Liquid nitrogen also acts as a coolant and with decreasing the environment’s temperature; leads to the freezing of the liquid droplets inside the cloud and forming the ice crystals (see the first chapter).
There are two Antonov-26 aircrafts which are used for the cloud seeding in Iran. The equipment mounted on these two aircrafts includes two sets, one for sensing the meteorological quantities, and another for injecting cloud seeding material inside the clouds.
Two aircrafts dedicated to the cloud seeding in the Yazd International airport
Inner view of the cloud seeding aircraft in Iran: the extended rear hatch is opened and the equipment are transferred to the inside.
Another inside view from an Iranian cloud seeding aircraft. A picture of the data recording equipment, and the injection management stand.
The set of the sensors, temperature sensor, hygrometer sensor and liquid water content sensor.
Radio altimeter Barometer
Radio communication system antenna
Flares containing silver iodide. Silver iodide complex in composition with pyrotechnic materials which are placed in Aluminium shields and are prepared as ejectable cartidges.
Blister glass for visual monitoring of the ice and liquid water in the clouds and the optical phenomena for the meteorological expert inside the aircraft.
Magazines for embedding ejectable cartridges, mountable on the fuselage.
The place on the fuselage to placement of the magazines containing the ejectable cartridges
Liquid nitrogen tanks, seated inside the seeding aircraft
The stand for management of the injection of the silver iodide cartridges, from inside the aircraft.
Connection pipes for connecting liquid nitrogen tanks to the output nozzle
Output nozzle of liquid nitrogen from fuselage
Blind areas and viewing ranges of AKSOPRI radar. Red circles are Shahr-e-Babak (Kerman province), Dehshir (Yazd province), and Kouhpayeh (Esfahan province) radars, respectively. The green areas are the radar viewing range and the rest of the areas inside the red circles are blind areas of radars.
Schematic of the procedures included in the conduction of a cloud seeding operation in Iran.
Forecasting and control center of the cloud seeding operations