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Cloud Seeding In The UAE Research Paper

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Water is not and abundant on earth, and the consumption of water is increasing substantially worldwide. There should be ways to maintain the demand for water and provide resources. This report discusses a technology that is stated as promising in which it creates precipitation from clouds. This technology is called cloud seeding, and it is a form of weather modification and a technique to increase the amount of precipitation in an area. This report will define cloud seeding, and how the technology of cloud seeding work. It will discuss the various technologies and methods used and under what circumstances a certain method is preferred. Most importantly this report will provide an understanding of the microphysics of clouds and the atmospheric conditions in which precipitation occurs. The area of interest used in this discussion is the United Arab Emirates since it is leading with its research center at the national center of meteorology. The UAE has been performing cloud seeding since 1990s and has been conducting research with the cooperation of reputable institutions worldwide to improve cloud seeding obtain great results of precipitations. The report will discuss cloud seeding operations that take place in the UAE by NCM and will provide details of how they are performed. Furthermore, it will tackle the benefits of cloud seeding and how it could improve the economy, the weather, and the how it could improve water supply.
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College of Engineering
Post Graduate Studies
Master of Civil Engineering
Professional Responsibility in Sustainable Environmental Design
CIV635
Spring 2020
Research Paper
Cloud Seeding in UAE
Student Name: Abdallah Badran ID: 1051739
Helal Al Mansoori ID: 1076242
Instructor’s Name: Dr. Evan Paleologos
Table of Contents
Abstract ........................................................................................................................................... 4
1. Introduction ............................................................................................................................. 5
2. History of Cloud Seeding in UAE ........................................................................................... 6
3. Cloud Generation ..................................................................................................................... 7
4. Cloud Microphysics ................................................................................................................. 8
5. Convective Clouds ................................................................................................................... 9
6. Cloud Seeding Methodologies................................................................................................. 9
6.1. Hygroscopic Cloud Seeding ........................................................................................... 10
6.2. Static Cloud Seeding ...................................................................................................... 10
6.3. Dynamic Cloud Seeding................................................................................................. 10
7. Cloud Seeding Operations by NCM ...................................................................................... 11
8. Benefits of Cloud Seeding ..................................................................................................... 11
9. Disadvantages of Cloud Seeding ........................................................................................... 13
10. Cloud Seeding Effect ......................................................................................................... 14
11. Cloud seeding Experiments ............................................................................................... 14
12. Climate and Environment and Health ................................................................................ 15
13. Cloud Seeding Projects ...................................................................................................... 15
14. Technologies used in cloud seeding. ................................................................................. 16
14.1. Aerial Cloud Seeding.................................................................................................. 16
14.2. Ground Cloud Seeding ............................................................................................... 16
14.3. Nanotechnology Cloud Seeding ................................................................................. 17
15. How Successful Is Cloud Seeding? ................................................................................... 18
16. Challenges in Cloud Seeding ............................................................................................. 19
16.1. Challenges Faced While in The Air ........................................................................... 19
16.2. Challenges Faced by The Monitoring Team .............................................................. 19
17. Conclusion ......................................................................................................................... 20
Bibliography ................................................................................................................................. 21
List of Figures
Figure 1 Cloud Seeding Operation ................................................................................................. 6
Figure 2 Cloud microphysics diagram ............................................................................................ 8
Figure 3 Process of Cloud Seeding ................................................................................................. 9
Figure 4 Materials used in Hygroscopic Cloud Seeding .............................................................. 10
Figure 5 Cloud Seeding Operations by NCM ............................................................................... 11
Figure 6 Aerial Cloud Seeding ..................................................................................................... 16
Figure 7 Ground Cloud Seeding ................................................................................................... 17
Figure 8 Experiment of Nanotechnology Cloud Seeding in UAE ................................................ 18
Abstract
Water is not and abundant on earth, and the consumption of water is increasing
substantially worldwide. There should be ways to maintain the demand for water and provide
resources. This report discusses a technology that is stated as promising in which it creates
precipitation from clouds. This technology is called cloud seeding, and it is a form of weather
modification and a technique to increase the amount of precipitation in an area. This report will
define cloud seeding, and how the technology of cloud seeding work. It will discuss the various
technologies and methods used and under what circumstances a certain method is preferred. Most
importantly this report will provide an understanding of the microphysics of clouds and the
atmospheric conditions in which precipitation occurs. The area of interest used in this discussion
is the United Arab Emirates since it is leading with its research center at the national center of
meteorology. The UAE has been performing cloud seeding since 1990s and has been conducting
research with the cooperation of reputable institutions worldwide to improve cloud seeding obtain
great results of precipitations. The report will discuss cloud seeding operations that take place in
the UAE by NCM and will provide details of how they are performed. Furthermore, it will tackle
the benefits of cloud seeding and how it could improve the economy, the weather, and the how it
could improve water supply.
1. Introduction
The most important natural renewable resource is water which is very important for all life
on earth. Ground water, rivers and reservoirs are the main traditional sources and supplies of water
in many regions of the world. These resources are under threat from ever-increasing demands due
to changes in land use and growing populations. Shortages and increase in the cost of potable water
is caused by the stress from droughts and high exploitation on water supplies. In many areas around
the world, water supplies have been steadily decreasing. In order to increase water resources, many
countries are conducting weather modification activities which are located in semiarid regions of
the world. India, Indonesia, Malaysia, Thailand and UAE are some of the countries involved in
weather modification activities [1].
Impacting and modifying the weather sounds like something from the future, but nowadays
many countries are trying to do it by using a technique called Cloud Seeding. Cloud seeding is
known as one of the weather modification processes, simply a method of artificially encouraging
a cloud to produce rain [2]. In addition to cloud seeding, other terms are also used such as man-
made precipitation enhancement, artificial weather modification, rainmaking and so on. It involves
spraying small particles such as dry ice and silver iodide aerosols into upper part of clouds to form
rain by trying to simulate the precipitation process in the clouds in order to increase it.
UAE was one of the first countries in the Middle East to take on cloud seeding technology
to increase its existing water sources and rainfall. Cloud seeding program started in UAE by
establishing UAE Research Program for Rain Enhancement Science (UAEREP). UAEREP is a
program designed to improve water security in arid and semi-arid areas around the world [3]. It is
not hard to understand why UAE has started cloud seeding program as it has an annual rate of
100mm of rainfall, high evaporation of surface water and draining ground water reserve. Research
lead to the development and refinement of high-tech and environmentally friendly sustainable
water solutions is a key challenge that must be overcome for the sake of those at risk of water
scarcity. Last year, UAE conducted 242 missions, which was up from 177 in 2016 [4].
Figure 1 Cloud Seeding Operation
2. History of Cloud Seeding in UAE
Cloud seeding experiments has been conducted by scientists since 1940s. The experiments
started with an encouraging discovery made in 1946 by a chemist working at the General Electric
Laboratory in New York.it was conducted by Mr. Vincent Schaefer in 1946 as he managed to
generate rainfall and create snowstorm in lab conditions. A series of trials followed the initial
findings that gave scientists success in converting flecks of dry ice (frozen carbon dioxide) into
supercool water droplets. These trials, several years later, led to experiments for rainfall
enhancement. The scientific benefits and belief in cloud seeding was huge, during the 1960s in the
US a project named “Stormfury” was undertaken to try and weaken cyclones. At the time they
thought it was worthy enough to test this method on a range of Atlantic hurricanes before they
realized the system was ineffective. This was due to the fact that the hurricanes themselves just
don’t contain enough water for the chemicals to bind to and have that much impact [5]. Scientific
research and technology development have made cloud seeding a popular mode of rainfall
enhancement, especially in the world’s most arid regions such as the UAE, Saudi Arabia, Jordan,
Morocco, Libya, and Syria. In 2009, the Chinese government conducted One of the most
noticeable cloud-seeding operations. It was launched over the capital city of Beijing. The
Indonesian government also used cloud seeding to extinguish jungle fires that were sending thick
smoke to the capital Jakarta. It was not easy to control the fire, so they sprinkle salt over the clouds
by using Indonesian military aircraft [6].
The UAE has been conducting cloud seeding operations since over a decade in order to
enhance rainfall in the country and bring down temperatures. Its cloud-seeding program started in
the 1990s. By early 2001 the program was cooperating with well-known organizations such as the
National Center for Atmospheric Research (NCAR) in Colorado, USA, as well as the
Witwatersrand University in South Africa and the US Space Agency, NASA. In 2005, the UAE
launched the UAE Prize for Excellence in Advancing the Science and Practice of Weather
Modification in collaboration with the World Meteorological Organization (WMO). This prize
was afterwards reshaped into the International Research Program for Rain Enhancement Science
In January 2015, it became the UAE Research Program for Rain Enhancement Science
(UAEREP). It was initiated by the United Arab Emirates Ministry of Presidential Affairs and
supervised by the UAE National Center of Meteorology & Seismology (NCMS) based in Abu
Dhabi. The UAE now has more than 60 networked weather stations in the UAE, a weather radar
network, and six aircraft for cloud seeding operations. Rain enhancement operations have focused
on the mountainous areas in the north-east of the country, where cumulus clouds gather in the
summer. Importantly, no harmful chemicals are used in UAE cloud seeding operations; our
specialized aircraft only use natural salts, and no harmful chemicals. In 2018, 46.5 mm of rainfall
was recorded in the UAE, according to the National Centre of Meteorology (NCM), despite the
country having had carried 184 cloud seeding operations. In 2019, the number rose to 101.1 mm
as 247 operations were undertaken. With larger amounts of water being recorded in the country,
more of it can be retained instead of evaporating as temperatures drop slightly and precipitation
occurs more frequently [7].
3. Cloud Generation
Clouds are the result of water vapor that is created by temperature increase on ground
surface. By temperature variations on different highest the vapor is lifted up and as it moves up it
cools down. Particles of different types exist and are being carried by air and vapor collides with
those particles. Vapor condenses around the air particles performing a chemical process known as
condensation of nuclei. The result of this process are bigger particles of water droplets; however,
those water droplets are light in weight that they keep on flying and they create clouds that we
know. This process requires certain atmospheric conditions and an important condition that needs
to be meet is relative humidity. Cloud formation requires high relative humidity between 60% to
100%. Relative humidity is the partial pressure of vaper over the total pressure of vapor, and to
understand why this is important the partial pressure is the amount of water molecules in a medium
and the total pressure is the capacity of that medium. Therefore, if the number of molecules is high
in the medium then relative density is high; however, if the medium is larger in capacity than the
number of molecules then the relative density is low. To simplify, if the number of droplets is high
then clouds are likely to be generated [8].
4. Cloud Microphysics
The natural process of cloud and the microphysics are controlled by certain rates. The first
rate is the amount of water or water mass and it is changing with atmospheric motions that carry
vapor at a rate 𝜏
−1as shown in the graph below. So, the water mass inters or leaves the volume;
thus, if the rate is high, then excess vapor will occur to proceed to the second phase which is the
condensation phase. The condensation phase also has a rate 𝜏𝑐𝑜𝑛𝑑
−1 this rate increases with the
increase of number of air particles, since the more particles in the volume the more vapor will have
its chance to condense around those particles. After condensation the particles will grow bigger
into droplets with a growth rate 𝜏𝑔𝑟𝑜𝑤𝑡ℎ
−1 . If the particles are large enough then precipitation will
result when those particles will fall at a rate 𝜏𝑓𝑎𝑙𝑙
−1 . However, if the water droplets are not heavy
enough they would evaporate on their way down at a rate 𝜏𝑒𝑣𝑎𝑝
−1 and go back into being a particle
and repeat the clouds generation cycle [9].
Figure 2 Cloud microphysics diagram
5. Convective Clouds
Clouds have different ways of formation and the type of clouds that are interesting in this
report are convective clouds. Convective clouds are clouds formed by the process of convection
and they are the kind of clouds that exist in the UAE. Convection occurs in warm air that rises
around an atmosphere that is high in density, higher than the density of the warm air. Connective
clouds are usually dense, and they contain large amount of water droplets. Cumulus clouds are a
popular type of convective clouds, and they are the target of seeding in the UAE [10].
6. Cloud Seeding Methodologies
After understanding the microphysics of clouds specially the volume in which particles are
entering and leaving at the condensation phase; we can now relate cloud seeding into the droplet’s
formation process. Cloud seeding helps by adding extra particles into the system in order to
increasing condensation on nuclei. There are three different techniques involved in cloud seeding.
Each technique is utilized based in the atmospheric conditions of clouds as well as the type of the
targeted clouds. The three techniques are: hygroscopic cloud seeding, static cloud seeding, and
dynamic cloud seeding [11].
Figure 3 Process of Cloud Seeding
6.1. Hygroscopic Cloud Seeding
The term hygroscopic means the tendency of a
substance to absorb water moisture from air, and in this
case, it is very crucial to have this property in the matter
of cloud seeding for condensation purpose. Hygroscopic
cloud seeding is applied on warm based clouds in which
they are very common in the UAE. Therefore, UAE is
using hygroscopic cloud seeding since the clouds are
convective cumulus type. The materials used in this methodology are salt minerals such as sodium,
potassium, and magnesium. Those salt minerals are considered embryos on which the raindrops
form. They increase the size of the droplets to result in acceleration of the chemical condensation
and thus, precipitation is likely to occur [11].
6.2. Static Cloud Seeding
The static cloud seeding method involves spreading silver iodide also known as dry ice
into clouds. Unlike hygroscopic, static cloud seeding is applied into cold based clouds that has a
temperature range between -10 and -25. Thus, glaciogenic materials need to be utilized in this
methodology as they enhance the ice crystals concentrations in clouds by either forming new
crystals or freezing cold droplets. Moreover, as the title suggests, static cloud seeding does not
involve air motion as all conditions would be stable during the process. For static cloud seeding to
be performed there are limitations with respect to the atmospheric conditions that need to be
existed. Therefore, this methodology cannot be applicable everywhere, and if successful results
obtained in an area, it does not mean the same will occur for another area, unless the atmospheric
conditions were to be replicated [12].
6.3. Dynamic Cloud Seeding
The main difference between static and dynamic cloud seeding that makes a great deal in
the process is air motion. The goal behind dynamic cloud seeding is to boost vertical air currents,
which allows significant amount of water droplets to pass through the clouds; as a result, the
precipitation chances are higher. Similar to static cloud seeding, dynamic cloud seeding also is
performed on cold based clouds. The materials used are also glaciogenic; however, dynamic cloud
seeding requires substantial amount of materials compared to the static method for higher chances
Figure 4 Materials used in Hygroscopic Cloud
Seeding
of precipitation. Dynamic cloud seeding is a sophisticated methodology that includes a long list of
steps in which any step is done inappropriately will require repeating the whole process [12].
7. Cloud Seeding Operations by NCM
NMC’s cloud seeding operations focus on how the UAE is reaching all the means to
providing sustainable water resources through encouraging research and innovations that relate to
water technologies. The UAE has an average annual rainfall of 100 mm, which suggests that it is
one of the global stressed countries in terms of water. Therefore, the UAE’s rain enhancement
program seeks to elevate the annual precipitation levels; and thus, enhance the ground water
resources. NCM conduct cloud seeding operations and relies on sophisticated network of radars to
monitor the country’s atmosphere at all times to provide data on clouds. A team of pilots and
technicians based at NCM’s designated operational rooms analyze this data. The team carries out
cloud seeding operations with high precision and efficiency once they detect ‘seedable’ clouds
[13].
Figure 5 Cloud Seeding Operations by NCM
8. Benefits of Cloud Seeding
Cloud seeding has many benefits for countries that will help to solve many issues that they
faced during time. The first benefit is that cloud seeding creates rain in the areas which rain is
badly needed, as it is perhaps the only way to produce rain. Cloud seeding attempts to create more
precipitation because of the need to have more condensation fall to the ground. When the clouds
are not strong enough to produce rain, but the conditions are right for rain positive impact is made
on the regions of our world that see consistent scarcity problems. This technique helps agricultural
workers produce more crops of better quality. It allows groundwater ecosystems to recharge. When
we are effective at this technology’s distribution, it begins to reduce the risks of famine on our
planet. People use silver iodine to induce rain production in areas where there is barely any
precipitation. Rain is important for keeping the area hydrated and fertile for growing crops and
other plants [14].
Another benefit is that cloud seeding boosts and improve of world economy. The more
farmers improve their crops quality and yield, the more money they will make to support their
families. So, where there is rain, there is farm produce and improvement. Farms that yield better
can help the local economy and feed the people. Cloud seeding can greatly improve the living
conditions in dry, arid places. Tourists also will come more if the area has good water with good
quantity. When there is more recreational waters and snowy slopes, people tend to go tourism [14].
Furthermore, cloud seeding can also regulate weather patterns in some country’s specific
locations. Cloud seeding in a way, gives us the ability to control the weather condition in a
particular area. It does not just make rain; it also regulates water vapor that in turn prevents
damages brought by destructive hails and storms. To create consistent weather condition around
airplane runways, airports frequently use cloud seeding. When fog, hail, or ice are present, then
the impacts on the aircraft can limit the ability to take off or land. The processes used in this
situation help to transform the precipitation or change its visual impact for pilots so that passenger
travel becomes safer. Crops in many areas face severe weather which can damage the products, so
cloud seeding is used to regulate the weather for the crops to grow in good conditions. Through
cloud seeding, the atmosphere’s water vapor will be more regulated, which will prevent damaging
hail and severe storms to occur [15].
Another benefit of cloud seeding is that it can make dry places and lands more suitable for
living and more hospitable. Local people have an impressive way of adapting to their natural
environment. But some regions have inhospitable places that are difficult for human to survive.
However, cloud seeding can increase rainfall rates in these areas, making them more hospitable
and this will attract more tourists and help the places’ overall economy as a result. The need of
cloud seeding is not to turn every desert green, but it is used to creates the potential for more
precipitation. If this process is used this method along mountain ranges where the snowpack serves
as the water supply for local communities, then it is possible to make more land suitable for living
because it will have additional resources available to use consistently [16].
Cloud seeding has a very low environmental impact as It also does not have any long-term
effects on the weather pattern. Cloud seeding also does not need any infrastructure. So, for
developing and under developing countries that continuously faces drought, this is a very cost-
effective option. Countries facing severe drought because of rain clouds getting blown away can
use cloud seeding to get rain. Cloud seeding promotes the formation of raindrop, which is essential
for drought-stricken regions or places that are suffering from water scarcity. A lot of countries that
are experiencing severe drought can utilize this technology to solve their problems [16].
9. Disadvantages of Cloud Seeding
As any new method discovered, there are many disadvantages for cloud seeding that might
affect its usage and efficiency. It is important to know that cloud seeding does involve using
chemicals in the air. This means that harmful chemical might be launched to the air. Chemicals
used in cloud seeding can potentially damage the environment, especially the plants cloud seeding
is intended to protect. There is no substantial study done on the implications of silver iodine on the
environment. Silver iodine may cause iodism”, a type of iodine poisoning where the patient
exhibits running nose, headache, skin rash, anemia, and diarrhea, among others. It has been found
to be highly toxic to fish, livestock, and humans. However, the complete effect of cloud seeding
on the environment as a whole is not fully known yet, but it might change in the future as more
research is done and completed [16].
Cloud seeding efficiency is not really proven until now. It has found that cloud seeding is
mostly used on clouds that already showing signs of rainfall. So, the best success happened when
you have a dark cloud and almost ready to rain. If cloud seeding is tried on a white normal cloud,
the chance of getting a positive outcome is 50/50. Also, seeded clouds may actually travel to
another location and do not cause precipitation on the intended location. Therefore, it can be argued
whether or not cloud seeding is truly effective in producing rain [17].
When any country wants to use cloud seeding, they must take account the high expense of
using this method. According to Smithsonian Magazine in 2014, the cost of an active program
could be as high as $427 per acre-foot. That means the expense of producing additional
precipitation would be higher than the economic benefits it provides. So, it is very expensive to
produce artificial rain. The most important reason for these expenses is that cloud seeding needs
planes in order to release the chemicals into clouds, which are hard to come by in places with very
minimal income. Poverty-stricken areas suffering drought or famine may need external funding to
have cloud seeding [18].
Cloud seeding may cause undesirable events if not regulated or controlled properly. When
the chemicals are released into clouds, there is no control of what type of weather that would form.
In many areas it is likely to have too much rain which can cause flooding. Places that naturally do
not get much rain or no rain at all usually do not have the infrastructure to handle so much
precipitation. With cloud seeding, these areas may become flooded quickly, causing more harm
than good. Some people even fear that, rather than solving water-shortage problems, cloud seeding
would just make them worse [19].
10. Cloud Seeding Effect
To evaluate the effect of cloud seeding it is required to go through a multistep process. The
first step is to develop a chain of events once the seeding materials are first introduced into clouds.
Next step requires determining the conditions in which the seeded clouds are exposed to under the
physical changes, as well as the different region in which those conditions and changes are taken
place. The third step involves figuring out the additional precipitation caused by seeding with
respect to a period or an entire season. These three steps are to demonstrate the sequence of events
that occurs to boost microphysical activities [20].
11. Cloud seeding Experiments
The experiments performed to witness the effect of cloud seeding involve ground-based
radars, cloud physics research aircrafts, and seeding aircrafts to release, track, and measure the
impact of cloud seeding. The seeding aircrafts use pyrotechnic flares to disperse the materials into
the targeted clouds. Flares are usually burn in place or dropped from the aircraft at certain intervals.
The burn in place flares are the most popular option since the materials reach the targeted clouds.
The seeding materials can be dispensed below cloud base from aircrafts; however, aircrafts need
to be equipped with wing-tipped generators that contain acetone along with the seeding materials.
Also, cloud seeding can be achieved from the top of the clouds using aircrafts that are equipped
with a rack to eject the seeding materials. Either approach will result in a large number of seeds to
allow the clouds to proceed with their microphysical activities [20].
12. Climate and Environment and Health
So far, all the published scientific literature has shown that cloud seeding causes no harm
to the environment. Hygroscopic cloud seeding uses very safe salt minerals that could be found in
non-polluted ground water. Precipitation results from cold based cloud seeding approaches (static
and dynamic) which use silver iodide as seeding material found to have silver concentration well
below acceptable environmental concentration of 50 micrograms per liter as set by U.S Public
Health Service. Also, it is stated the concentration of salt minerals as well as silver iodide is far
below the concentration found in the iodized salt used for human consumption. There are no
significant environmental impacts have been observed around cloud-seeding operations as well as
the projects that have been carried for 30 to 40 years. Furthermore, there is no noticeable difference
in taste between normal rainwater and rainwater from seeded clouds [20].
13. Cloud Seeding Projects
One of the very important cloud seeding projects is located in West Texas between the
Permian Basin and the South Plains, at the headwaters of the Colorado River of Texas. The cloud
seeding project of the Colorado River Municipal Water District started in 1971 to generate
additional precipitation and create runoff into two reservoirs Lake Thomas and E.V. Spence. The
cloud seeding operations are conducted from April to October with experts, special weather radars,
and equipped aircrafts. The Big Spring district cloud seeding program covers 2.6 million acres
between Lubbock and Midland. It is stated that the cost of cloud seeding in this program is between
4 to 5 cents per acre. In general, such programs are funded by large water districts and
municipalities. Besides the Big Spring program, two cloud seeding projects were established in
2000 in the northern High Plains of Texas. These projects cover 8.2 million acres and they are
sponsored by the North Plains Groundwater Conservation District. Various other projects beside
the ones mentioned are carried and being carried in over 40 other countries, as a result there is a
significance to the operations of cloud seeding to enhance rainfall and thus increase water
conservations [20].
14. Technologies used in cloud seeding.
UAE always uses the latest available technologies paired with sophisticated radars to
observe the atmosphere and the related changes. Networked automatic weather stations distributed
across the UAE, air quality stations, a sophisticated Doppler weather radar network, mobile radars,
and Beechcraft King Air C90 aircraft for cloud seeding operations
14.1. Aerial Cloud Seeding
Aerial cloud seeding is the process of delivering a seeding agent by aircraft - either at the
cloud base or cloud top. There are several types of aircraft available with a wide range of abilities
and cabin capacities. Top seeding allows for direct injection of the seeding agent into the
supercooled cloud top. Base seeding is the release of the seeding agent in the updraft of a cloud
base. Aerial cloud seeding is the most frequently used cloud seeding method in the UAE is using
an aircraft to drop the condensation nuclei. The condensation nuclei are fitted into flares that are
loaded on the Aeroplan. These flares are released into the clouds where they accelerate
condensation, forming water droplets weighing enough to create rainfall. For cloud seeding in the
UAE, the National Centre of Meteorology (NCM) targets the dense clouds moving over the
Arabian Gulf, in an attempt to increase rainfall yield by at least 15 per cent [21].
Figure 6 Aerial Cloud Seeding
14.2. Ground Cloud Seeding
The second of technology of cloud seeding used in the UAE is the ground cloud seeding.
This system involves ground generators that are currently placed in the mountainous terrains of
the Hafeet and Fujairah areas. These generators shoot salt flares into the clouds from the ground,
instead of dropping them from the plane to for increased rains. UAE uses specially designed and
manufactured solutions to meet the specific challenges of ground-based cloud seeding. When
weather at the seeding location is critical, complete meteorological stations can be co-located with
both fixed and mobile ground-based units [21].
Ground-based seeding generator has two types of which are remote controlled ground-
based generators and manual ground-based generators. Firstly, remote controlled ground-based
generators are remote system utilizes a communication link, such as Iridium. This rugged system
is designed to withstand the extremes of any storm system that may pass over the site. They are
constructed to function even in extreme rime icing and operate under the most demanding of
weather conditions. Secondly, manual ground-based generators are a manual system that is similar
to the remote system, except there is no need for communication link, microprocessor or weather
data collection equipment. The relatively simple task of operating the valves and switches is
performed onsite [22].
Figure 7 Ground Cloud Seeding
14.3. Nanotechnology Cloud Seeding
Given the overall cloud seeding impact on the UAE, the country is always in search of new
and efficient technologies to create rain. Lately, the NCM started to experiment a new cloud
seeding method that involves nanotechnology. Until now, this method has been tested in the
northern and eastern regions of the UAE. The NCM hopes that this technology will make cloud
seeding in UAE more effective and achieve more rainfall. Nanotechnology is a specially designed
nanomaterials that are being sprayed into clouds to determine if they are more effective than
existing materials. This technology uses salt crystals enclosed in titanium dioxide nanoparticle
veneers as opposed to flares. These crystals are then injected into the existing clouds to make rain
particles in them denser and more likely to pour down as rainfall [21].
Figure 8 Experiment of Nanotechnology Cloud Seeding in UAE
15. How Successful Is Cloud Seeding?
With proper design of cloud seeding programs operated by expertise, it is stated that cloud
seeding can increase seasonal precipitation with an appreciated and beneficial amount. The
American Meteorological Society (AMS) and the World Meteorological Organization (WMO)
both issued statements that’s suggest cloud seeding is successful if the technology used is efficient.
Based on experience that lasted over 50 years it is suggested that cloud seeding creates
precipitation in wet seasons more than dry seasons. During seasons in which convective clouds
are not in large number to treat, the precipitation is reduced. However, countries that adapt cloud
seeding technologies believe that cloud seeding is a valid option for long-term water management
strategy for providing freshwater. Countries that use cloud seeding are committed to use it for a
period of time that could last for several years. The project of Big Spring which utilized Federal
funds assessed its long-term cloud seeding program and it is claimed that using silver iodide would
produce significant amount of rain by enhancing individual cells within clouds. The Big Spring
program has witnessed an average increase in the seasonal precipitation by 20 to 30 percent [23].
Also, a study similar to the Big Spring has utilized cloud seeding in the city of San Angelo
for 5 years and have reached an increase in precipitation of 25-42 percent from the seasonal
precipitation. The Texas Department of Agriculture as well as the Texas Department of Licensing
and Regulations have combined their effort to conduct evaluations of cloud seeding operations in
the state of Texas. Combining a total of 494 cloud seeding operations a statistical analysis was
performed and estimated that cloud seeding operations generated 129,272 acre-feet of water. It is
suggested that seeded storm lived 57 percent longer than the unseeded storms and covered 29
percent more area. The evaluation estimated that cloud seeding operations done on thunderstorms
have provided 75 ice nuclei per liter of air within the cloud mass. The available evidence of at least
eight years of experiments and research in West Texas suggest that when cloud seeding is
performed properly in timely manner and accuracy, it contributes in longer lasting rains [23].
16. Challenges in Cloud Seeding
Cloud seeding operations are very challenging in several aspects such as, reaching the right
and targeted cloud, the right time to seed the targeted cloud, and the right amount of seeding
materials to disperse. The previous mentioned challenges were only with respect to the operation
itself. There other challenges that are faced at the monitoring station during or after the operation
is conducted. Those challenges are: gauging the amount of precipitation resulted from the
operation, distinguishing the seeded clouds from the non-seeded clouds, and figuring out weather
precipitation resulted from seeding operations or occurred naturally [24].
16.1. Challenges Faced While in The Air
The first set of challenges happen before and at the time of conducting cloud seeding
operations. The operations as mentioned earlier must be conducted in timely manner and precisely,
therefore, there must be a sequence of events during the operation to ensure the operation is
conducted properly. Some cloud seeding methodologies like dynamic cloud seeding has 11 steps
that need to be insured that are done in the right way independently, and any failure in a step might
provide inaccurate results in the operation. The clouds that need to be seeded are convective that
take the shape of a cauliflower, and they need to have an initiated moisture content and seeded to
increase that moisture content. It is difficult to measure the right amount of seeding material to
seed the targeted clouds it might depend in the atmospheric conditions of that specific cloud [24].
16.2. Challenges Faced by The Monitoring Team
The second set of challenges happen during or after conducting the cloud seeding
operations and it is faced by the monitoring team at the monitoring station. A cloud seeding
operation is monitored via advanced radars and gauges and dealing with climate changes is not an
easy task, as nature is never predictable. Not all clouds are the same, and not all circumstances and
conditions are the same; therefore, it is hard to predict precipitation out of a single cloud.
Moreover, clouds need to have their moisture content ready to seed and be increased, but usually
clouds could initiate precipitation without the need of seeding specially during rainy season. Thus,
it is very challenging to measure the success of a single cloud. Precipitation might result naturally,
and it is hard to distinguish between natural rain and the rain resulted from cloud seeding.
Furthermore, it is hard to control the operation and initiate precipitation in a specified area, in fact,
due to wind forces the seeded clouds might move to a totally different direction and create rainfall
in a totally different area. Thus, it might be difficult to obtain rain in an area of choice to enhance
its features or irrigate its plants [24].
17. Conclusion
Cloud seeding is cost effective even though it will affect agriculture soil. Government and
human being should adopt and follow different strategies for water sources management which
include rainwater harvesting, artificial recharge of aquifers, conjunct use of surface and ground
water before using cloud seeding. Another cause is that cloud seeding is found not to be foolproof
as of the moment because it mostly affects the clouds that are already showing signs of rainfall.
So, it is not known if it is actually the cause of rain. In general, trying to cure drought is an ongoing
battle, and the latest technology used for this is cloud seeding. Determining if the technique is good
or bad might not be as easy as you might assume. The opportunities for achieving high rates of
progress in agriculture sector and industrial growth is connected directly with the availability of
water resource of a nation, so cloud seeding becomes the necessity to tackle this critical situation.
The cloud seeding technology is very closely associated with water resource management.
Artificial rain in UAE has helped the country battle extreme temperature, weather and
create favorable environmental conditions for all. Sometimes heavy rainfalls lead to slight
inconveniences in everyday life, but as long as you know how to deal with the rain, you can keep
yourself and those around you safe. Although the immediate aim of the UAE Research Program
for Rain Enhancement Science is to increase the UAE’s rainfall and boost freshwater supply, the
intention is to generate results that could have wider applications for countries that might benefit
from advances in rain growth technology. Reflecting the importance of securing our future water
supplies, the UAE government is driving the innovation needed to make rain enhancement a key
tool in our efforts to ensure adequate supplies of freshwater for people in arid and semi-arid regions
around the world. The UAE’s farsightedness is not just limited to creating alternative water sources
for its people. It is also determined to excel in economic and social standards to become one of the
best places to live on Earth. The same agenda is also visible in the UAE’s theme for the next year,
2020 towards the Next 50 years [25].
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Article
Full-text available
Deep convective clouds (DCCs) play a crucial role in the general circulation, energy, and hydrological cycle of our climate system. Aerosol particles can influence DCCs by altering cloud properties, precipitation regimes, and radiation balance. Previous studies reported both invigoration and suppression of DCCs by aerosols, but few were concerned with the whole life cycle of DCC. By conducting multiple monthlong cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macrophysical and microphysical properties of summer convective clouds and precipitation in the tropics and midlatitudes, this study provides a comprehensive view of how aerosols affect cloud cover, cloud top height, and radiative forcing. We found that although the widely accepted theory of DCC invigoration due to aerosol's thermodynamic effect (additional latent heat release from freezing of greater amount of cloud water) may work during the growing stage, it is microphysical effect influenced by aerosols that drives the dramatic increase in cloud cover, cloud top height, and cloud thickness at the mature and dissipation stages by inducing larger amounts of smaller but longer-lasting ice particles in the stratiform/anvils of DCCs, even when thermodynamic invigoration of convection is absent. The thermodynamic invigoration effect contributes up to ∼27% of total increase in cloud cover. The overall aerosol indirect effect is an atmospheric radiative warming (3-5 W⋅m(-2)) and a surface cooling (-5 to -8 W⋅m(-2)). The modeling findings are confirmed by the analyses of ample measurements made at three sites of distinctly different environments.
Article
Throughout the western United States and other semiarid mountainous regions across the globe, water supplies are fed primarily through the melting of snowpack. Growing populations place higher demands on water, while warmer winters and earlier springs reduce its supply. Water managers are tantalized by the prospect of cloud seeding as a way to increase winter snowfall, thereby shifting the balance between water supply and demand. Little direct scientific evidence exists that confirms even the basic physical hypothesis upon which cloud seeding relies. The intent of glaciogenic seeding of orographic clouds is to introduce aerosol into a cloud to alter the natural development of cloud particles and enhance wintertime precipitation in a targeted region. The hypothesized chain of events begins with the introduction of silver iodide aerosol into cloud regions containing supercooled liquid water, leading to the nucleation of ice crystals, followed by ice particle growth to sizes sufficiently large such that snow falls to the ground. Despite numerous experiments spanning several decades, no direct observations of this process exist. Here, measurements from radars and aircraft-mounted cloud physics probes are presented that together show the initiation, growth, and fallout to the mountain surface of ice crystals resulting from glaciogenic seeding. These data, by themselves, do not address the question of cloud seeding efficacy, but rather form a critical set of observations necessary for such investigations. These observations are unambiguous and provide details of the physical chain of events following the introduction of glaciogenic cloud seeding aerosol into supercooled liquid orographic clouds.
Howw does cloud-seeding in the UAE work?
  • G Duncan
G. Duncan, "Howw does cloud-seeding in the UAE work?," The National, 12 January 2020. [Online]. Available: https://www.thenational.ae/uae/environment/how-does-cloudseeding-in-the-uae-work-1.811961. [Accessed 9 June 2020].
The rain men: everything you need to know about UAE's cloud seeding missions
  • J Dennehy
J. Dennehy, "The rain men: everything you need to know about UAE's cloud seeding missions," The National, 17 January 2018. [Online]. Available: https://www.thenational.ae/uae/environment/the-rain-men-everything-you-need-toknow-about-uae-s-cloud-seeding-missions-1.696289#:~:text=Last%20year%20it%20conducted%20242,177%20were%20undertaken% 20in%202016.. [Accessed 9 June 2020].
What Is Cloud Seeding?
  • D Lewis
D. Lewis, "What Is Cloud Seeding?," The Fact Site, [Online]. Available: https://www.thefactsite.com/what-is-cloud-seeding/. [Accessed 10 June 2020].
History of cloud seeding
  • A K B Chief
A. K. B. Chief, "History of cloud seeding," Gulf News, 2013.
Review of Cloud Seeding Experiments to Enhance Precipitation
"Review of Cloud Seeding Experiments to Enhance Precipitation," Bulletin of the American Meteorological Society, vol. 80, no. 5, pp. 805-820, 1999.
Cloud Seeding; Its Prospects and Concerns in the Modern World
  • S Malik
  • H Bano
  • R A R S Ahmad
S. Malik, H. Bano and R. A. R. S. Ahmad, "Cloud Seeding; Its Prospects and Concerns in the Modern World," nt. J. Pure App, vol. 6 (5), no. 2320 -7051, pp. 791-796, 2018.
PRECIPITATION EVALUATION OF THE NORTH DAKOTA CLOUD MODIFICATION PROJECT (NDCMP) USING RAIN GAUGE OBSERVATIONS
M. E. Tuftedal, "PRECIPITATION EVALUATION OF THE NORTH DAKOTA CLOUD MODIFICATION PROJECT (NDCMP) USING RAIN GAUGE OBSERVATIONS," Theses and Dissertations, vol. 1, no. 2591, pp. 1-104, 2019.