ACTIVE INTERVENTIONS IN THE ATMOSPHERE USING AVIATION
The use of aircraft for active response operations in the atmosphere involves modifying them to be able to transport response materials to the cloud target areas. By conducting experiments over the last few years, we want to implement this method in as many areas as possible throughout the country. It is among the most effective cloud seeding methods available.
Depending on the type of aircraft and the type of active intervention in the atmosphere, airplanes are adapted to carry smoke flares on the wings and ejectable cartridges on the underside. Thus, interventions on cloud systems to stimulate rainfall and combat hail using aircraft are carried out by two methods:
- seeding the top of the cloud by direct injection of crystallization nuclei
- seeding the base of the cloud by dispersing the condensation nuclei in the hot part.
Aircraft crews need to collaborate effectively with operational meteorologists on the ground, given the limited information generated by aircraft radar compared to the detailed, comprehensive view of clouds generated by ground-based radars. During the warm season, convective systems can develop rapidly and strongly, requiring vigilance on the part of both teams. The safety of our stakeholders is our highest priority.
For interventions in the upper cloud zone, it is the meteorologist on the ground who indicates to the aircraft the area where the seeding material should be released. For interventions at the base of the cloud, the pilot decides to position the aircraft near the intervention area in order to carry out the operation safely. Communication between all team members is essential.
Because of the unpredictability of the evolution and the high speed with which flight conditions change, especially in the warm season, this method is highly risky, the personnel involved need to be trained, the equipment high-performance and the meteorologists very well trained. This is an effective method for both combating hail and stimulating rainfall.
ACTIVE INTERVENTION IN THE ATMOSPHERE USING ROCKETS
Active interventions in the atmosphere using hail rockets are one of the most effective methods of intervening on hail-generating cloud systems. This approach involves the use of rockets that disperse silver iodide on their upward trajectory in a continuous and uniform manner over a well-defined time interval.
The anti-hail rockets used in these interventions are specially designed to carry the seeding material to the target area in the cloud.
This method of intervention can be defined as a complex system, and a sufficiently large number of Release Points is required for optimal coverage of a protection area.
Active atmospheric interventions over cloud systems to combat hail using specialized rockets are successfully used in several countries. This method has been successfully used for a long time in: Moldova, Georgia, Bulgaria, Serbia, Croatia, Slovenia, China, Argentina, Brazil and the Russian Federation.
In recent decades, as climate change has intensified, scientists and farmers alike have increasingly opted for active rocket interventions. Not only does it help to increase rainfall, but it also helps to reduce the devastating effects of hail and has a positive impact on agriculture, especially when it comes to crop protection.
ACTIVE INTERVENTIONS IN THE ATMOSPHERE USING LAND-BASED GENERATORS
The ground generator method for active atmospheric intervention is a complex method and requires careful selection of positions and number of generators to protect a given area of interest. To implement such a system, numerous studies are required prior to design.
Ground-based generators used in active intervention in the atmosphere operate with a mixture of substances, which maintain their physical and chemical properties throughout the temperature range in which they produce silver iodide aerosols.
The efficiency of ground-based generators in dispersing seed material in the target area inside the cloud is limited. The best results are obtained in active interventions in the atmosphere to increase the amount of precipitation, especially in mountain regions where ground temperatures are already close to the optimal range. In some cases, these areas are practically inside the clouds.
In conditions other than those mentioned above, when ground-based generators are used, aerosols are produced close to the earth's surface and not in or near clouds. These aerosols are then entrained in the atmosphere by updrafts and reach the target area in the cloud.
This type of intervention is much less effective than using missile systems or airplanes, but has advantages in terms of operating costs. Another advantage of this method is the ease with which the generators can be controlled remotely and also does not require airspace restriction when in use.
A more effective approach to combat hail by this method is to disperse artificial condensation nuclei (silver iodide) long before the convective system reaches the area, as a preventive method to combat hail, but also to stimulate precipitation.
Atmospheric turbulence and convection can transport these condensation nuclei from near-earth condensation nucleators inside convective clouds to the level where ice nucleation occurs. This process leads to a decrease in hail size. However, the method does not provide a guarantee as to the exact area where the condensation nuclei will arrive, as they can be influenced by atmospheric conditions and cloud movement.
Active interventions in the atmosphere using Helium Balloons
In addition to the methods outlined above, we have integrated cloud seeding using helium balloons into our active atmospheric intervention system.
Cloud seeding technology for rainfall stimulation and hail control using helium ballooning is a safe and automated method that allows for both efficient and rapid intervention. Their release can be controlled manually or remotely, and once done, dispersal of the seeding agent will occur in less than 10 minutes.
The balloon is made from biodegradable latex, resulting in little to no environmental impact. Inside, it contains 1m cubic metre of helium and an electronic control system, whose functionality is to ignite the cartridge, which in turn can contain a charge of 23g silver iodide or 220g sodium chloride.
This technology is suitable for both stratiform cloud formations, present in the cold season, and convective cloud formations, present in the warm season. After completing its mission, the balloon self-destructs by activating a heat source, which creates a hole in the balloon, causing it to fall to the ground.
What advantages do we gain by using helium balloons for active intervention? The intervention material can be spread at an altitude within a flexible range compared to previous methods. At the same time, the seeding material hooked onto the bubble can easily be changed.
It is important to note that this type of intervention is effective in conditions of thermal inversion or when the isotherm level is low, when other methods cannot be used.
WEATHER RADARS
Meteorological radars that we have in IAA’s equipment are high-precision devices used for detection and analysis of atmospheric phenomena, such as cloud formations associated with precipitation and storms. These systems provide detailed information about cloud structure and composition, their location, developmental stage, the intensity of phenomena, as well as their direction of movement and speed. This information are vital for improved early warnings, efficient resource management during extreme weather events, and coordinated weather modification activities.
The IAA’s radar equipment can monitor meteorological phenomena within a range of up to 200 km, accurately identifying meteorological hazardous conditions and estimating the intensity of precipitation and the velocity of cloud system movement. These systems provide three-dimensional analyses of cloud formations (both horizontally and vertically), offering insights information, the upper and lower cloud boundaries, areas where clouds generate ground-reaching precipitation, and the aggregation state of water within the cloud. These capabilities make meteorological radars indispensable tools for weather modification efforts.
The data collected by these radars complete the information provided by the National Meteorological Administration (ANM) radar network, providing a much more comprehensive and detailed understanding of the meteorological conditions in the studied area. IAA specialists analyze and study the data from all available sources to understand the structure of atmospheric phenomena and intervene as efficiently as possible in targeted regions.
Weather radars are equipped with high-performance antennas, powerful transmitters, and highly sensitive receivers capable of detecting signals from small particles over long distances, enabling the analysis of complex atmospheric phenomena. Their power supply and climate control systems are specially designed to ensure operation under the most challenging conditions associated with hazardous weather phenomena, guaranteeing optimal functionality at all times.’