That year, Ralph had begun flying to storms aboard NOAA planes during a powerful El Niño event. In 1998, scientists published a groundbreaking paper detailing the “moisture fluxes from atmospheric rivers.” Ralph said when he read the research, “that was a lightbulb going off for me.” As a graduate student at UCLA in 1990, he was astonished when a sudden storm dumped a large share of L.A.’s average annual rainfall in his rain gauge within about six hours. showed that a low-level jet stream ahead of a cold front was connected to heavy rains in Britain.ĭecades ago, Ralph was fascinated with big, drenching storms even before he heard the term atmospheric rivers. The concept of atmospheric rivers began to emerge in the 1970s, when research in the U.K. Since then, Ralph said, more than 500 articles have been published in scientific journals with titles focusing on atmospheric rivers. The science of atmospheric rivers has come a long way since Ralph and his colleagues published a 2004 study drawing on data from satellites and reconnaissance flights.
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“And we’ve just recently, in the last 10 or 15 years, figured out really how to look for them, how to measure them best and how to characterize them.” “ARs sort of hide in plain sight,” Ralph said. Looking out the window, Ralph said he had briefly seen through holes in the clouds, which revealed what looked like whitecaps rolling on the stormy ocean.Īside from those brief glimpses through the storm, the cirrus clouds resembled a flat blanket beneath the deep blue sky. So it’s a pretty classic atmospheric river.”Īfter examining the data, Ralph stepped into the cockpit and sat chatting with co-pilot Rick de Triquet. “For the bottom 10,000 feet, we have total saturation. “It’s essentially as moist as it can get,” De Solo said. The radar detected heavy rains beneath the clouds. Two lines tracking dew point and temperature converged. Lower down, within the storm, the winds were pushing water vapor at speeds of up to 90 mph.Īs the jet cruised above the clouds, De Solo saw the atmospheric river’s signature appear in the data. The dropsondes recorded high-altitude winds of up to 190 mph. Once she checked the data, she transmitted them via satellite and the measurements flowed into computer models that feed weather forecasts. The red one is your wind direction, and your pink one, magenta one is your wind velocity.” “The blue one is our relative humidity,” De Solo said. Sofia de Solo, a meteorologist, watched the measurements appear on her monitor as four distinct lines. But it instantly began transmitting data. There was no way to see the dropsonde launch. The pressurized air from the cabin pushed the dropsonde out into the thin atmosphere, and the device fell toward the clouds.Ĭlimate & Environment California faces catastrophic flood dangers - and a need to invest billions in protectionĪ new state plan for the Central Valley calls for spending as much as $30 billion over 30 years to prepare for the dangers. There was a whoosh of air as the spring-loaded gate valve opened. Then, he gave the word: “Release sond now.” Speaking quietly into his headset, meteorologist Rich Henning signaled to colleagues at the back of the plane that it was almost time. The crew planned to drop 30 “sonds,” as they called them, over a precise set of coordinates. “We’re just about to launch,” Weinmann said.
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Weinmann jotted down its serial number, and a colleague placed it into a launch tube behind his seat, then closed the hatch. Rocky Weinmann, a technician, held a dropsonde and plugged a cord into the device to activate it. The devices, called dropsondes, are equipped with parachutes and as they descend transmit data back to the plane - wind speed and direction, temperature and humidity - before hitting the ocean and sinking. Each measured 16 inches long and nearly 3 inches wide and resembled an oversized tube of Pringles. The jet also has a separate Doppler radar system in the tail, which captures cross-section images as it passes over a storm.Īs the aircraft approached the atmospheric river, two crew members removed shiny silver wrapping from the first of dozens of cylinders. An image of the Muppet character is emblazoned on the side of the plane. Gonzo has a specialized radar system for approaching storms, requiring an elongated nose that gives the plane its nickname.
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