Cloud Seeding Experiments: A New Perspective on Utilizing Aerial Drones

A new experimental cloud seeding approach is described in this study. This conceptual cloud seeding framework is motivated by the severe drought in California. The new sustainable approach is aiming to provide a cost effective solution for cloud seeding. Particularly with emphasis towards potentially stimulating the enhancement of precipitation from warm clouds as well as the possibility of reducing coastal fog in California.

An unmanned aerial vehicle (i.e., drone) has been specifically designed to perform cloud seeding experiments. The experiment would call for a fleet of battery powered aerial drones that could be launched into flight with a maximum weight of 55 lbs, including the payload weight of 10 lbs. Once at flight, in the called for favorable meteorological conditions, the clouds will be seeded with micro sized salt particles using the hopper dispersal system onboard the vehicle. Once all the salt particles onboard are dispersed, another drone will be launched to seed the same cloud, and so forth until all the seeding agent has been dispersed. The hopper system is designed to disperse the salt particles at different rates to then allow for determining which rate has the most promising outcome for certain locations or cloud types.

Using empirical and conditional probabilities looking at specific meteorological parameters, an idealized time to perform cloud seeding experiments was calculated. Using the available METAR data, a climate study of Arcata, CA focuses on cloud base height and relative humidity values for the past 20 years along with precipitation records for the past 10 years. METAR data for the city of Medford, OR has also been analyzed and compared as it is the closest location to the target area that has available upper air data. Moreover, in order to show that the design for the aerial drones would not be limited in flight, upper air wind speeds for March 2015 were analyzed from Medford, OR and from Oakland, CA daily soundings. Overall, based on the three conditions list above, the most probable time of year to perform the cloud seeding experiment is during March for the target location.