3D s.a. is one of the most innovative companies in the world regarding Protection against Adverse Weather Phenomena. It is a member of the Weather Modification Association and undertakes such programs since 1981.

The management of weather conditions is performed by using specially modified aircrafts, weather radars and qualified staff. The company’s goals are to increase rain and snow falls (in order to face the drought and to store up water), and to protect from hail (so that the damage caused both to crops and to people’s fortunes are restrained).

Such programs for weather management and protection from adverse  weather phenomena can be performed during the whole year. Hail protection is usually performed during the warm months (when the stormy clouds most develop), and projects for the increase of rain/snow have better results during the cold months.

The method used for the performance of such programs is based on the penetration of condensation cells in the atmosphere, wherever there is enough humidity. However, because of their absence, either it’s impossible that water drops or ice cells are formed, or due to the small number of cells, big embryos are created which fall to the ground as hail.

When 3D s.a. carries out such programs, it uses the direct penetration method, which means the seeding of Silver Iodide (AgI) or dry ice from aircrafts to the target area at the right moment, in order to have the best results possible. This is how the available humidity of the atmosphere is divided into more cells – ice crystals, which finally fall on the ground as rain or snow.

Various researches in the past have shown that the environment is not affected by the clouds seeding. As for the animals, plants or the ground, in areas where the projects of weather modification were carried out, the quantities of AgI have not exceeded those already existing in the environment.

Weather management programs cannot reduce the drought expected for summer nor create clouds if there is no humidity in the atmosphere. It is possible, though, when the conditions are favorable to seed, to increase the water stored from rain or snow during winter, so that it is properly managed during the dry months.

Similar projects are carried out all over the world. The digital weather radars’ capacities help to observe clouds better and give quantitative and qualitative weather data in real time.

Due to the fact that we must:

• Foresee in time and precisely the importance of the weather problem and take the proper measures to face it.
• Protect some specific predetermined rural or urban areas from hail.
• Increase the available quantities of water to develop some basic fields of the economy, such as energy, tourism, agriculture, which wane constantly.
• Have sufficient quantities of water for the present, but even more in the future for urban use.

As a result, we have to manage in a better way the atmospheric water in order to:

• Cause rain or snow in areas that we have already chosen (catchment basin, lake, forest, mountain, specific areas of storage etc) so that problems of scarcity and desertification
• Protect crops from hail by transforming it into rain
• Create and store water when possible and consume manage it later (for example in periods of drought)

HAIL SUPPRESSION

Hail suppression is a field in which scientists have been interested since 1896. Many methods and application modes have been developed at international level, but they all conclude to the same point. They are all based on the way that the hailstone is formed and where the mechanism of its suppression is based. The most expanded method nowadays is the beneficial competition between hailstones while they are embryos.

Beneficial competition is based on the assumption that the water volume V in a cloud is limited, and if that water is divided equally over N precipitation elements, then the radius r of these elements follows from N⋅r3 ≈ V. By injecting many extra ice-forming nuclei into the cloud at the right time and at the right place, where in weak updrafts hail formation is beginning, it should then be possible to reduce the average size of fully-grown hailstones. Small hailstones may melt on the way down and are less damaging anyway. Used amounts of silver iodide (AgI) are not large and are estimated to produce no serious ecological side-effects (BORLAND and CHANGNON, 1977;
DESSENS, 1998).

In the atmosphere, hail presupposes always the existence of developed or stormy clouds.
In order that a stormy cloud is formed in the atmosphere, the following must occur:

a. Enough humidity
b. Turbulence (updrafts-downdrafts) and
c. Condensation cells

The steam of the atmosphere adhere to the condensation cells, which are small particles of dust, smoke and salt crystals being in constant movement due to the turbulence. As a result, small water drops or ice crystals are formed and keep moving and growing because steam keeps adhering to them creating the cloud. When this process takes place at parts of the cloud where there is super cooled water, then hailstones are created that grow constantly due to the turbulence and finally start falling on the ground because of their weight. The mechanism of the creation of hail, meaning its permanent motion up and down in the atmosphere, can be confirmed if we examine a hail stone, where we can see the different layers of ice which surround it.

According to the theory of hailstones’ beneficial competition, when there are few cells, the size of the hailstones created is big and they manage to fall on the ground causing damages. By adding more cells to a cloud, more 

hailstones of smaller size are formed and they have already melt before touching the ground. The material used for the increase of the embryos is Silver Iodide, which is first being evaporated and then quenched, forcing its molecules to form big quantities of microscopic particles (1019 particles/kg of AgI). These particles are in some way seeded in the cloud at the right moment and acting as condensation cells they steal the available water.

According to the existing weather conditions, the crucial indicators beyond which hail clouds are going to be seeded are determined. Then a detailed control by digital weather radars id performed revealing the crucial areas that need seeding. As soon as such cloud is shown, they give the order to an aircraft which flies to the area of the hail cloud and injects flares of Silver Iodide, which are attached either to the aircraft’s fuselage or to its wings.

The way of seeding is decided depending on the cloud’s development rhythm, its movement, the icing levels, the isothermal of 0°C, and the way of the cloud’s creation. The direct targeting technique that 3D s.a. applies focuses to the updrafts’ areas of the common (isolated) cells and to the updrafts of the developing clouds’ feeder cells, situated at the sides of the mature multicellular storms. In other words, this technique restrains the available super cooled water in liquid form within the cloud’s area, where the hail stones are created and increase. Several methods of seeding are used, depending on factors such as the kind of development, the visibility, the closeness from the ground and the time of the day. The reason why there are several methods is that the injection of seeding material to the clouds’ developing areas is possible in order to cover as many conditions as possible.

A good forecast of actual hail probability is needed to start defensive preparations, both by covering up glasshouses and other breakables and maybe by starting some action. When actually cumulonimbus clouds are approaching, then it is useful to find out whether they are indeed likely to produce hail. Radar is useful to sense hail-generating power of clouds, and radar performance has increased significantly lately.

3D s.a. HAIL SUPPRESSION PROJECTS

• 1981-82: Hail protection program of O.G.A. (Agricultural Insurance Organization), technical advisor of French company RUGGERI
• 1986-88: Hail protection program of EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION), representative and technical advisor of company INTERA
• Spring-Summer 1992-93: Hail protection program of EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION), joint venture 3D-C.I.C.-Avionic
• Spring-Summer 1997-98: Hail protection program EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)
• Spring-Summer 1999-2000: Hail protection program EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)
• Spring-Summer 2001- 2002: Hail protection program EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)
• Spring-Summer 2004- 2008: Hail protection program of EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)
• Spring-Summer 2009- 2013: Hail protection program of EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)
• Spring-Summer 2014- 2019: Hail Protection program of EL.G.A. (AGRICULTURAL INSURANCE ORGANIZATION)

PRECIPITATION INCREASE (RAINFALL – SNOWFALL)

It is well known that, usually, the natural procedure of rain is not effective because of the lack of sufficient quantities of natural icing cells. As a result, the injection of artificial icing cells in the cloud’s parts where there is water in super cooling condition (-5 to -25°C) leads to the creation of more ice crystals. These cause additional quantities of frost, due to the fact that they keep growing. This intervention has as a result the transformation of a quantity of water in super cooling condition into rain or snow, which falls on the ground.

This principal is the theoretical base of the rain increase projects, especially during the cold period. The increase of the precipitation is achieved by seeding adequate quantities of Silver Iodide or particles of dry ice to the areas of super cooling of a cloud, letting the atmosphere do all the rest.

The effectiveness of such programs has been determined as a percentage of the liquid water existing in a cloud and that falls on the ground in some form of precipitation. This effectiveness is reinforced by seeding clouds, using the technique of the direct targeting by aircrafts. In the beginning, a very good weather forecast is performed, inspection of the area using special weather radars, localization of the crucial areas, flight with research aircrafts in order to collect the final weather data of the seeding area, cloud seeding at a specific area.

The choice of the right position of intervention (seeding) is very important in programs for the increase of precipitation, so that the courses of the atmospheric deposits (water drops, ice crystals) end to the expected target area (catchment basin). Given that the ice crystals grow in different rhythms, which depend on the temperature and the available quantities of water in liquid condition (cloud droplets), it’s obvious that the limit speed of their course towards the ground will vary (as well as the time of fusion). It is of major importance to determine the courses, so that the injection of the seeding material takes place to the right position at the right time, in order to have the best results possible, using specific mathematic types. The methods and cloud seeding procedures for the increase of precipitation are sufficiently documented and are used in many programs weather management all over the world. It is not possible though to increase the precipitation in an area, if there is not some kind of cloud in the atmosphere, if there is not any available quantity of humidity which can be liquefied. By managing the atmosphere’s available humidity properly, we assure that its available water falls where we have already decided (increase of catchment in ground deposit tanks), in order to manage it properly later.

RAIN ENHANCEMENT PROJECTS

• Winter 1994: Rain enhancement program EYDAP (Athens Water Company
• June – July 2001: Pilot program for rain enhancement in Central Greece
• February – November 2006 : Participation in rain enhancement program, Saudi Arabia
• 2013 – 2015 project DAPHNE is focused in the development of necessary scientific tools, to support the potentiality and applicability of a well designed precipitation enhancement program, by applying state-of-the-science modeling tools, performing measurement campaigns and cloud seeding experiments, and investigating the impact of its implementation on the environment. It is applied over the Thessaly plain, which is known as the most vital agricultural area in Greece, and thus weather and climate play a very important role in nation's socio-economic status

The Project DAPHNE 2013-2105

The project aims at tackling the problem of drought in the Thessaly by means of Weather Modification. The Thessaly plain is known to be the most vital agricultural area in Greece, and thus the weather and climate play a very important role in its socio-economic status.

The main objective is to develop the necessary scientific tools to support the application of a well designed rainfall enhancement program, investigate its importance for the present and future decades in the thread of climate change and importantly, assess thoroughly the impact of its implementation on the environment. The objectives to be accomplished within the framework of the DAPHNE project include:

1. Gathering of experimental data, concerning atmospheric circulations and cloud parameters from in-cloud-flight measurements, especially dedicated to the weather modification project.
2. Developing state-of-the-art of modeling tools that will assist the better knowledge and improve the analysis and evaluation of the weather modification impacts on weather first and climate then.
3. Investigating the impact of climate change on drought, with emphasis on the area of Thessaly, by applying the modeling tools developed and suggesting mitigation strategies to the policy makers.
4. Performing an integrated environmental impact assessment study to investigate the impact of weather modification program on water and soil.
5. Organizing dissemination activities to inform authorities and the public about the potentiality and applicability of a well designed scientific weather modification program over Thessaly.