Cloud seeding is an important tool that’s been used in California to boost the mountain snowpack. It’s often done by aircraft flying in dangerous storm conditions. Now drones are poised to take over some of that work, possibly alleviating some of the risk and saving money.
|Written byMatt Weiser||Published on Feb. 29, 2016||Read time Approx. 6 minutes|
Scientists at the Desert Research Institute in Reno recently succeeded in conducting the world’s first cloud-seeding exercise using an octocopter drone. The goal is to make cloud seeding more affordable and more adaptable to adverse weather conditions.
Cloud seeding has been conducted successfully for decades over the Sierra Nevada. It involves discharging silver iodide particles from aircraft. Usually this is done by igniting flares – just like a roadside emergency flare – attached to a plane’s wings. The flares contain silver iodide, which causes water droplets within the clouds to form ice crystals, which eventually become snowflakes as they grow larger.
Studies have shown cloud seeding, when done correctly, can boost the snowpack between 8 and 15 percent. But flights are often limited by icing conditions, which pose a danger to pilots and people on the ground in the event of a crash.
That’s where drones come in. A drone can operate in marginal conditions that might be too dangerous for a manned flight. A drone can also fly closer to the ground, in some circumstances, to take advantage of ideal atmospheric conditions. And it can do this more affordably.
Water Deeply recently spoke with Adam Watts, an assistant research professor at the Desert Research Institute, about the successful trial. He also discussed plans with partner Drone America to eventually launch “swarms” of drones to seed large areas.
Water Deeply: Why use drones in cloud seeding?
Adam Watts: Cloud seeding, when done from the air, does involve some risks, such as flying into icing conditions. Using unmanned aircraft reduces the risk to humans, both in the aircraft and on the ground. So it allows you to explore more options that might involve taking on a bit more risk than you’d want if you’re using manned aircraft. Another potential benefit is cost. If all you need to do is take a lightweight payload up, of course a drone can do that without also carrying a human aloft.
Water Deeply: Are there any advantages for cloud seeding that drones bring to the party?
Adam Watts: The types of payloads we developed for the unmanned aircraft are very similar to what we use for the manned aircraft. I would say the difference and the potential advantage might lie again in that risk area where you might be able to use an unmanned aircraft to fly closer to the ground than you would allow your manned aircraft to fly. You might also be able to have an unmanned aircraft deployed potentially at night or under other conditions. You’re able to take on additional mission profiles that a manned aircraft wouldn’t be able to do without incorporating an unacceptable level of risk.
Water Deeply: In what ways was your recent experiment successful?
Adam Watts: With the octocopter from Drone America, we’ve demonstrated the ability of an autonomous unmanned aircraft to fly a cloud-seeding payload. To our knowledge, it seems to be a world first. I don’t believe anybody else out there has flown a cloud-seeding payload aboard any kind of unmanned aircraft. It feels kind of weird saying that, but let us go ahead and say that. This is a big deal, but its going to be an even bigger deal as we go forward.
Water Deeply: Why is it going to be a big deal?
Adam Watts: I think it’s going to be a big deal because we’re going to be developing concepts of operation that are going to be helpful to a large suite of other applications. Such as how we deploy the aircraft with the kinds of forecasting information we use to support navigation, and procedures for recovery of the aircraft. It’s fair to say we’re pioneering some things that are going to be enabling the cloud-seeding mission but will support some other things.
As it specifically relates to cloud seeding, I wouldn’t want to get overblown about the implications for solving the water crisis. But down the road, it could be something that becomes a useful tool for enhancing precipitation in larger areas. Fixed cloud-seeding generators on the ground, they can put out a lot of effort when weather conditions are right. But they have to have the wind set up in the right way. You can envision a scenario in the future where, in addition to ground generators, you might have remote stations with these autonomous aircraft staged for launch. That might expand your ability in responding to a forecast in the safety and warmth of your office to do aerial cloud seeding.
Water Deeply: How long before drones can be used for active cloud seeding?
Adam Watts: If we do everything we are going to try to do, if the weather conditions cooperate, the project this year should result in an operational cloud-seeding flight. That’s going to be at a modest scale. How long might it be before this is readily available for the organizations that do cloud seeding? That’s hard to say. It’s going to depend on funding to continue to develop these tools.
Water Deeply: How does the cloud-seeding payload work?
Watts: It’s pretty similar to the flare racks on manned aircraft. This is simply a smaller version of that. In the same way that a pilot of a manned aircraft flips a switch to ignite the flares, we’ll be able to do that from the ground. We’ll be able to do that on the basis of where the aircraft is located, and what the weather radar tells us about where the clouds are.
Water Deeply: What needs to happen legally for this to become a regular thing?
Adam Watts: From the standpoint of operating from the side of a mountain, we’re going to be operating what’s called “beyond visual flight.” That’s a challenge we’re going to have to overcome. Beyond line of site operations are currently very tightly regulated in the U.S. So we’ll be working closely with our partners in the FAA on making sure we satisfy those requirements. This is going to be kind of a pioneer, pathfinding sort of project. We’re in a time where we’re seeing some maturation of regulations governing unmanned aircraft. We’re seeing some exciting technology being incorporated to be sure we can fly unmanned aircraft safely. My hope is that any regulations are going to be adaptable to the situations and to the technologies that enable safe operations.
I also hope the public continues to see unmanned aircraft as really valuable tools that actually increase our ability to fly safely. And that the regulations adopted at all the levels reflect that and that there aren’t knee-jerk regulations that restrict our ability to operate. Other countries are doing it safely, and we don’t want to fall behind in these high-tech fields.
Water Deeply: Do you foresee that drones will replace manned aircraft in cloud seeding?
Adam Watts: I really think that complementing each other is what we will see. I don’t like to think of unmanned aircraft in terms of replacing manned aircraft. We talk about certain scenarios where I think a pilot would be glad to no longer be flying a particular mission because it’s risky.
Water Deeply: Is range a limitation in the drones you are using?
Adam Watts: It is, and i think you’ve hit on one of the reasons we can envision drones are not going to replace manned aircraft. You might have a couple of hours flight duration (with a drone). Which could be really useful for some cloud-seeding events, but might not be sufficient in others, and for those you’d want a manned aircraft. At the same time, we’re seeing rapid advances in propulsion technologies as we see batteries get better and new types of advanced propulsion get better.
Water Deeply: What does the future hold?
Adam Watts: Among the next steps will be improvements to the payload and putting the payload on board the type of aircraft that’s going to give us the kind of performance we want.
More and better is going to be coming along. For one thing that (octocopter) aircraft is certainly not ideal for the cloud-seeding mission. Really, to get big successes like we want, we’re going to be using a newly developed platform. What we’re working on with our industry partner, Drone America, is a fixed-wing aircraft that’s going to be much better able to fly in the wind and in icing conditions and it will carry a larger cloud-seeding payload too.
We might be able to use swarms or networks of these drones flying in a formation, which would then really be cost effective and would allow us to seed areas and enhance precipitation over a larger area than you can do with a single aircraft — maybe without increasing costs much beyond using a manned aircraft.
Top image: A drone operated by the Desert Research Institute and Drone America successfully deploys a cloud-seeding flare in Spanish Springs, Nev., on January 27, 2016. (Kevin Clifford/Drone America)