The Design and Execution of Precipitation Enhancement of the convective clouds / cloud seeding near water catchment area with Rocket Launch Technology
The proposed method of cloud seeding also referred as precipitation enhancement is based on carrying the Glaciogenic reagent into clouds with Rockets. The basic equipments of the cloud seeding technology consists of Rocket System to be launched to deliver the reagent containing 10.28 % of AgI, automated control system ACS-MRL-5 Meteorological Radar for collecting radar tracking data of clouds and its processing. The system allows scanning the cloudy atmosphere for identifying the possible convective region formation. Methods of cloud seeding in practice are Static, Dynamic and Hygroscopic. Static Cloud seeding approach involves introducing sprays of Silver Iodide (AgI) into the clouds. The moisture in the clouds then condenses around the crystals produced by silver iodide. This essentially makes rain clouds more effective in dispersing their water contents. Dynamic Cloud Seeding encourages more water to pass through the clouds by boosting the vertical air currents thus resulting into more rain. In Hygroscopic cloud seeding approach we disperse hygroscopic material like dry ice or salt through the means of flares or explosives well below the cloud base. Due to coalescence the salts particles grows in size and comes down with rain.
The phases for Cloud Seeding include the following activities:
- Assessment of pre-conditions for PE by climatological study of synoptic situations and upper-air conditions for clouds and precipitation, time-space and frequency distribution of local cloudiness and precipitation in the process of site selection in Upper Thracian Lowland: as pre-experimental stage for aircraft-laboratory in-situ experiment Cloud Modification.
- Using the radar records of cloud observations for the classification of cloud systems and their
- It serves also as local resource contributing to the planning, execution and evaluation the effects of cloud seeding for PE, as well as in assessing the efficiency of combined cloud seeding experiment.
- Design of experiment (including the choice of seeding means and agent) based on convective cloud climatology and the present knowledge of cloud macro- and microphysics and cloud modification after seeding with glaciogenic agent as well as on the skill in cloud seeding.
- Implementation of an experiment with randomization, using extensive radar measurements and data analyses with the purpose to verify the “precipitation acceleration” for convective cloud seeding by Glaciogenic agent in real (field) conditions
Methodology of radar cloud and precipitation observations
RADAR observations and Launch Operations following methodology is in use.
- The radar operator executes an hourly volume scan using an angular velocity of 4 turns per minute for 16 antenna turns with elevation angle growing from 1.5o to 21.3 o.
- If no echo is found within 150 km of the radar, but forecast indicates convective development, then, operator changes the observation regime to every half an hour scans.
- If a radar echo is detected over the Island or less than 15 km offshore, the observation regime is changed to a scan every 15 minutes.
- When a radar echo is found over the water catchment inside a radius of 150 km, the period of scanning is turned to 5-6 min.
One of the main objectives of target cloud seeding experiment is to determine the speed and direction of the target. The radar information about the displacement vector of the floating target clouds is used for the selection of the experimental cloud systems and delimitation of the experimental units during the Launch and also to calculate the intensity and volume of the precipitation in the target in the evaluation process.
The program-technical complex “ASU-Elia” helps in managing the rocket launchers network. It also allows to:
- Control and guide an unlimited number of remote RL from one monitor via radio and cellular communication channels
- Perform data packets exchange between Command Center and several rocket points in a parallel mode.
- Conduct full automatic control of rockets launch process while logging rockets quantity, coordinates and launch time.
- Increase the speed of hail and hail dangerous clouds seeding by increasing the efficiency of commands transmission, execution and control of execution of rockets launch commands and by simultaneous parallel transmission of commands to several Rocket Launcher.
- Collect data from the automatic meteorological stations built into “Elia-2” and to build maps of space distribution of temperature, humidity, pressure, precipitation amount, hail kinetic energy above the background of regional map.
Functions of the Rocket
The timing system of the rocket pyrotechnic payload container has to be set for 7 sec while launch the rocket. The electric firing mechanism is simply inserted in the rocket once the rocket is inserted in the launcher. A remote launch mechanism of the rocket launcher provides the firing impulse to the rocket and parallel activates the pyro lock of the payload container of the rocket to get free at right time of the seeding event in flight. The booster motor burns for 1.2 sec and accelerates the Pyrotechnic Mixture container up to 400 m/s. after the motor burn time the Rocket Payload bay pyrotechnic combustion of AgI mix is initiated and continues the flight till 4 km further.
Rocket booster continues the journey without rapid speed loss starts spraying the AgI pyromix at preset time till 16 sec. these AgI particles then moved with the updraft wind of approx 5 m/s which later reacts with cold environment of clouds forming the aerosol CCN particles for cloud seeding.
Physics of AgI based Reagent
for the purpose of cloud seeding various compositions of AgI mix were used and tested onboard the rocket in Indian Tropical environment. For the small rockets of cloud seeding AgI is considered as best seeding material. Its effectiveness is strongly affected by temperatures. Its best between 0 to -5 degree Celsius.
Emission of AgI Silver iodide from the payload bay of Rocket
The payload of Gyan ANjali Rocket is packed with 400 gm of Silver iodide composition based containing 11.8 % of silver iodide; a composition based in studies of Bulgarian weather modification experiments and produced in Engenious Aerospace Ltd. This combination of AgI produces active Nuclei per gram of mixture at – 10 degree Celsius i,e nuclei per container. At an average speed of 200 m/s there are active nuclei per meter.
Scheme of Daily Experiment