Making it Rain

 Back long ago was part of a group that investigated the ability to make it rain.  Aimed at general agriculture  Its a long ago desire, with many failures and also expression of pitfalls involved.  Well here it is again.   Now working they say. By the UAE, using Drones.  Looking deeper to see how it might link to what we did then. 

Weather Control via Drone,  By Logan Kugler,  Commissioned by CACM Staff, September 2, 2021

A remarkable video released by the National Center of Meteorology of the United Arab Emirates (UAE) shows a rarity: a heavy downpour of rain in the desert.

However, the rain isn't the rare part (although the UAE gets just about four inches of rain per year). What's rare is the rain's source: the downpour was caused by drones.

Unmanned drones flew into a bank of clouds, then used electricity to cause the droplets locked in the clouds to fall. The result was a man-made downpour.

The project is based on research from the U.K.'s University of Reading, where researchers modeled and measured how rain droplets in a cloud behave when electrically charged. Theoretically, if two droplets have the same charge, they may be attracted to each other and merge; the new, bigger droplet may then be heavy enough to fall. Charge enough droplets and you can, in theory, induce rainfall.

The footage released by the UAE suggests this type of weather control works in practice.

It is the latest effort at "cloud seeding," which is the practice of inducing rain by dispersing material into the clouds to encourage condensation. Cloud seeding has been practiced for the last 50 years, says Daniel Rosenfeld, a professor of atmospheric sciences at Hebrew University, Jerusalem, and an expert in weather modification. Historically, a number of means have been used to induce rain in clouds, including dropping salt into them, a process the UAE already uses for cloud seeding.

Drones armed with electrical charges are just the latest in a string of attempts to coax rain from the sky via cloud seeding. This attempt, funded by the United Arab Emirates Rain Enhancement Program (UAE REP), may be more significant than past efforts, because cloud seeding runs into some big obstacles that the drone program is trying to solve, says Rosenfeld.

It is difficult to measure how well cloud seeding methods work, since you never know how much rain would have fallen without the seeding. It's also hard to tell which clouds are ripe for seeding in the first place, and even if you find clouds bearing enough droplets, seeding them in a timely fashion is not easy.

"The UAE REP program is a serious effort to address all these questions in a scientifically sound way," says Rosenfeld. As part of the program, the UAE government gave research teams at the University of Reading one of nine grants totaling $15 million.

The Reading researchers used their funding across multiple projects that led to the drone cloud seeding.

First, they simulated the behavior of water droplets in clouds. Researchers Torsten Auerswald and Maarten Ambaum used a technique called "ABC flow" to model how droplets behave. Because the technique simulates motion using far less computing power than other methods, they also were able to simulate how electrical charges could influence droplets, providing a clear, measurable picture of how electric-charge cloud seeding could work.  .... '