Controlling Weather with Lasers
Jason Ahrns, a graduate student at the University of Alaska-Fairbanks, goes sprite-chasing at night during electrical storms. Here he captures column-shaped red sprites over Red Willow County, Nebraska, on Aug. 12, 2013.
A “jellyfish” sprite photographed over Republic County, Kansas, on August 3, 2013. "I have very good low light eyesight, and I've watched tons of sprites in real time on the context cameras so I know exactly what and where to look. I was watching intently out the window while I snapped these shots, and the camera caught a sprite that I didn't see," writes Ahrns in his blog: http://musubk.blogspot.fr/2013/08/sprites-2013-update-4.html
Like flames from a butane lighter, three blue jets (slightly blurred due to the motion of the aircraft) appear above the lightning-lit clouds in this photo taken over Republic County, Kansas, on August 3, 2013. Ahrns describes this picture as the "the cream of the crop," due to the difficult nature of capturing blue jets. "Since jets tend to hug the top of the clouds it's understandable that they're more difficult for a ground observer to see/photograph, so it makes sense that being up in a sprite-chasing aircraft would give me a serious advantage," he writes.
"Unlike sprites, blue jets aren’t directly triggered by lightning, but seem to be somehow related to the presence of hail storms," reports the Smithsonian: http://blogs.smithsonianmag.com/artscience/2013/08/scientists-capture-rare-photographs-of-red-lightning/.
Red sprite over Canadian County, Oklahoma, on August 6, 2013. "I was also able to see quite a few jets with my naked eyes! That's a first for me, and I'm always excited to see a new sky phenomenon for myself. I still haven't been able to see a sprite naked-eye, and it impresses me just how difficult that actually is," Ahrns writes.
Ahrns' Nikon D7000 on a flexible tripod points out the window of the sprite-chasing aircraft, a Gulfstream V with the National Center for Atmospheric Research. "I butted the camera up against the window glass and put my weight on it to get rid of most of the wobbles and light leaks, but the motion of the aircraft itself still showed up, especially when we hit a patch of turbulence (we are, you know, flying right next to a thunderstorm)," he writes.
What could be cooler than zapping clouds to make them do as you wish? The dream has been around a long time. Is it nuts?
A decades ago the only weather-related laser research hitting the science news pages was the limited success of New Mexico researchers who were trying to trigger lightning with high-powered lasers shot from a mountain top at passing thunderheads.
This is a pretty dangerous work, since the North American monsoon is what powers the thunderstorms in the Southwest and they can be pretty violently electric. I remember asking one of these researchers what would happen if they succeeded. Would their laser get blasted to bits by an angry Zeus? Silly me. They used mirrors to launch the beam perpendicular from its source. Ben Franklin would be so proud.
But all that laser and lightning stuff is not where it’s at any more. More recently it’s been discovered that lasers can influence the water condensation in the air, which is a little lever that could perhaps be made into a bigger lever that could make it possible to squeeze more rain out of clouds in dry regions. Maybe. Hopefully.
The prospect is good enough that there was a Conference on Laser-based Weather Control in 2011 in Geneva. This year the same organizers are putting together their second international meeting: the Conference on Laser, Weather and Climate (LWC2013) at the World Meteorological Organisation (WMO), once again in Geneva.
Their website explained that “ultra-short lasers launched into the atmosphere have emerged as a promising prospective tool for weather modulation and climate studies.” They point out such prospects as the old lightning control dream, laser-assisted condensation, and then add “the striking similarities between the non-linear optical propagation and natural phenomena like rogue waves or climate bifurcations.”
I will not pretend to understand more than a sliver of that last phrase, but I look forward to hearing about more specific science coming out of the conference itself, on Sept. 16-18. Meetings like these are critical for an unusual field because they require such a wide array of talents — meteorologists, atmospheric physicists, electrical engineers (someone has to work the laser), and so on — who may not all be employed at the same institution. Hopes are that collaborations will ensue. Long gone are the days when two guys with a kite, key and a jar could do meaningful science.
IMAGE: Tornado and lightning during a thunderstorm. (National Weather Service/F. Smith)