Tom Walker of Alexandria, Va., emailed me the question below about the sidebar to the May 1 story on the big Vortex 2 tornado experiment. The headline for the sidebar says: “Scientists are surprised to find [low reflectivity] ribbon in thunderstorm data.”
“After seeing the image of an LRR [low reflectivity ribbon] from the Center for Severe Weather Research that you referenced in the sidebar of that article, I noticed that the area of light rain and small raindrops resembled a massive airfoil. Do you think that the LRR could be having a similar effect as that of a super-efficient airfoil? “
“Also, remembering the vortices created by jumbo jets at takeoff and landing, do you think that a related phenomenon could be at work in the airfoil-like LRRs?”
I passed the question on to Josh Wurman, one of the scientists who is leading the VORTEX 2 experiment and who told me about the LRR.
He responded: “The LRR is only very recently discovered. Scientists do not know what causes it, or if it plays an important role in how the thunderstorm evolves or if it makes tornadoes.
“Tom Walker’s idea is interesting, but doesn’t seem on the right track to me. An airfoil is a material object that deflects air. The LRR is not material; if anything, it has less non-gaseous material than surrounding areas since it is an area of light precipitation surrounded by much more intense precipitation. Since the LRR is not material, it is unlikely to be deflecting air, so is unlikely to be producing any wake-like vortices.”
Wurman also told me that he and others are now writing papers for scientific journals about the LRR and these will certainly lead to discussions and hypotheses about what causes the phenomenon and whether it has any effect on supercells. Possibily this could lead to the answer to the big question Wurman has about the LRR: “Does this affect tornadoes, or is it like a rainbow, scientifically cool but with no effect on the weather?”