![]() Within thunderclouds, turbulence spawned by updrafts causes tiny ice crystals and water droplets (called "hydrometeors") to bump around and collide. Dennis Boccippio, an atmospheric scientist with the NSSTC lightning team, explains why: "Florida experiences two sea breezes: one from the east coast and one from the west coast." The "push" between these two breezes forces ground air upward and triggers thunderstorms. The new maps show that Florida, for example, is one place where the rate of strikes is unusually high. The development of space-based optical detectors was a major advance, giving researchers their first complete picture of planet-wide lightning activity.Ībove: Data from space-based optical sensors reveal the uneven distribution of worldwide lightning strikes. ![]() But because such sensors have a limited range, oceans and low-population areas had been poorly sampled. Ground-based lightning detectors employing radio-frequency sensors provide high-quality local measurements. By analyzing a narrow wavelength band around 777 nanometers - which is in the near-infrared region of the spectrum - they can spot brief lightning flashes even under daytime conditions.īefore OTD and LIS, global lightning patterns were known only approximately. "Basically, these optical sensors use high-speed cameras to look for changes in the tops of clouds, changes your eyes can't see," he explains. The LIS was launched on the Tropical Rainfall Measuring Mission satellite in 1997 and it's still going strong." "The OTD was launched in 1995 and we got five good years out of it. ![]() "The OTD and the LIS are two optical sensors that we've flown in lower Earth orbit," says Christian, whose team developed the sensors. This new perspective on lightning is possible thanks to two satellite-based detectors: the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS). Sign up for EXPRESS SCIENCE NEWS delivery
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