In this in-depth interview with Open Access Government, The National Center of Meteorology in the UAE chart the priorities to advance the science and technology of rain enhancement. They detail why it’s important to support research in weather modification and how this impacts society. The concern that almost half of the world’s population could be faced with high water stress by 2030 is also raised here.
Also, we learn the extent to which recent technological developments offer the potential of using rain enhancement as an important supplement to existing sources of groundwater and desalinated water. Finally, The National Center of Meteorology explains to us why water security is a critical challenge for the future.
What are the priorities to advance the science and technology of rain enhancement? Why is it important to support research in weather modification and how does this impact society?
The main challenge facing arid regions is water scarcity caused by a low amount of rainfall and a high rate of evaporation accompanied by heavy groundwater usage. In addition to that, population growth can apply stress on natural water resources. For the arid countries of the Middle East and North Africa (MENA) region, water sustainability has become one of their most urgent economic and security challenges given projected demand from rapidly expanding populations. With groundwater supplies decreasing rapidly throughout the MENA region, the consequent rise in the production of desalinated water is imposing further energy costs that are already straining national budgets.
In its foresight to innovate for the future, the UAE started taking a keen interest in rain enhancement, with cloud seeding operations initiated in 1990. The UAE now has more than 60 networked weather stations, an integrated radar network, and five specialised aircraft for seeding operations. 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). The prize was thereafter amended to the UAE Research Program for Rain Enhancement Science in 2016.
The UAE Research Program for Rain Enhancement Science is an international research initiative, managed by the National Center of Meteorology in the UAE, designed to advance the science and technology of rain enhancement by offering managed grant assistance to selected teams of researchers. Continuous innovation in the complex science of weather modification, and specifically rain enhancement, is critical to ultimately alleviate the suffering of water-stressed communities. In its efforts to continue pushing for cutting-edge advancements, the UAE Research Program for Rain Enhancement Science released an updated list in 2020 concerning targeted research areas for its fourth cycle. These areas were selected by a team of international atmospheric research experts based on the outputs of the nine research projects awarded between 2015- 2017, the outcomes of the 4th International Rain Enhancement Forum and the recommendations from the World Meteorological Organization (WMO) expert meeting held in Geneva and the 4th cycle program solicitation workshop. Placing high priority on emerging technologies and innovations, and multi-institutional, multi-national collaborations to drive the development of rain enhancement science, the updated areas include advances in weather modelling and forecasting using artificial intelligence and ensemble modelling, evaluation of rain enhancement efficacy through the utilisation of cloud chamber and statistical methods, innovations in rain enhancement systems through the integration of new measurement and numerical tools, and leveraging novel rain enhancement models, among others.
Tell us about the concern that almost half of the world’s population could be faced with high water stress by 2030
Much of the projected total global population increase of three billion over the next three decades will occur in developing countries, putting severe pressure on already limited supplies of potable water. There is a real threat that the stress imposed by increasing water scarcity could trigger conflicts. As water security is an essential element of national security, there is an increasing imperative for countries to strengthen their water resilience by promoting research and development, investment in new technologies, more efficient resource conservation and effective international partnerships.
In addition to the immediate aim of the UAE Program for Rain Enhancement Science to increase the UAE’s rainfall and enhance freshwater supply, the intention is also to generate results that could have wider applications for countries that might benefit from advances in rain augmentation science and technology.
To what extent would you say that recent technological developments offer the potential to use rain enhancement as an important supplement to existing sources of groundwater and desalinated water?
The National Center of Meteorology conducted randomised statistical experiments held in 2004, in coordination with NCAR, with the results showing an increase in the amount of rainfall between 10-15% in the turbid atmosphere, as the pollutants and aerosols available contribute as condensation nuclei. This percentage could increase to reach 25% in clean atmosphere conditions. One cubic metre of a cloud can hold 500 tonnes of water, while the frequently found seedable clouds (usually small in size) have a diameter of 5 km with a depth more than 7 km, containing a significant amount of water, and proving that cloud seeding can produce a valuable amount of water through rainfall and, therefore, helping to recharge the aquifers and groundwater storage.
In arid and semi-arid regions, rain enhancement could offer a viable, cost-effective supplement to existing water technologies such as desalination, which is around 60 times more expensive than cloud seeding methods.
About cloud seeding assessment tools
Several approaches for cloud seeding assessment are taking place in different countries using different methodologies, usually, the statistical randomisation method has proven to be the most common method of validating cloud seeding operations. Other cloud seeding assessment tools include choosing two different areas having the same climatic conditions, where cloud seeding operations are applied in the targeted area as opposed to the controlled area (where cloud seeding operations do not take place), through this method we can assess the improvement of rainfall amount over the targeted area compared to the controlled area. Daily, other cloud seeding committees use sophisticated radars such as a dual- polarized doppler radar, which responds to both horizontally and vertically polarized radio waves simultaneously and can reveal the microphysical development chain inside the cloud. High-resolution models have been used recently to specify the amenable clouds for seeding and can help in the validation process.
Different types of clouds & cloud seeding operations
Cloud seeding operations mainly depend on the type of the cloud, using the hygroscopic agent is much more suitable to warm clouds such as convective and cumuliform clouds (which experience good updrafts at the base of those clouds), using the hygroscopic salts will stimulate the microphysical process such as condensation, collision and coalescence processes that lead to the growth of droplets causing them to become heavier and eventually makes them fall down to the ground as rain. Using silver iodide is more amenable to be used in cold clouds, seeding agents such as silver iodide will support the main natural ice nucleation process in the deficiency of ice crystals, where the silver iodide is considered as an embryo for this process to take place. The ice crystals will grow efficiently at the expense of super cold water droplets available at higher concentration (between -5 to -7 degree Celsius). Additionally, we can use hygroscopic and silver iodide agents in mixed-phase clouds, while the hygroscopic agent can also enhance the ice nucleation process by enlarging the super cold water droplets in the mixed-phase cloud (frequently found in the UAE, especially during summer).
Is cloud seeding becoming a real science?
It is already a real science because it mimics the atmosphere in a cloud chamber, at which we can control weather elements for making studies on the physical or electrical properties of clouds, where the National Center of Meteorology has assessed the effectiveness of the innovative cloud seeding materials on the condensation process and rainfall enhancement, this novel cloud seeding agent was awarded by the UAE Research Program for Rain Enhancement Science during its 1st Cycle.
Newer weather modification techniques
Ensure the continuity of rain enhancement science is important for us, while employing the latest technologies such as artificial intelligence and machine learning to break new ground in cloud seeding to enhance the water supplies in the future around the World. Various projects are underway to deal with the creation of artificial updrafts to induce rain; targeted observation and seeding through unmanned aerial vehicles; and advanced experimental-numerical approaches to rain enhancement. For more information on the projects, please visit:
Creating artificial updrafts
The National Center of Meteorology is currently working on a project with Dr Ali Abshaev: “On the creation of updrafts for the formation of clouds and rainfall”, more of which you can read about, here.