San Diego, like the rest of California, was deluged by multiple atmospheric river weather events over the 2022-2023 rainy season, which both considerably eased the state’s drought and created new types of weather hazards.
As the climate changes, so too do ways to predict and monitor the weather. To that end, the Scripps Institution of Oceanography’s Center for Western Weather and Water Extremes (W3E) is leading the Atmospheric River Reconnaissance program with “Hurricane Hunter” aircraft from the U.S. Air Force Reserve 53rd Weather Reconnaissance Squadron and NOAA.
The research will be invaluable for tracking future weather models in a rapidly changing climate, said Dr. Anna Wilson, W3E’s field research manager. “With all this data we can improve our understanding of the physical processes and represent them better.”
This has immediate ramifications for the region, Wilson said, which was built for conditions that are either rapidly changing or no longer exist. “Our existing infrastructure was built a long time ago with the setup of the natural reservoir that is the snowpack, and we don’t have that any more to count on,” she said.
This year, California’s snowpack is one of the largest ever, following years of drought — an example of the “climate whiplash” expected in increasingly extreme weather conditions.
The joint program aims to collect data on atmospheric rivers, which occur when winds over the Pacific Ocean push moisture-rich warm air toward the West Coast. When it is pushed upward into cooler air, the resulting condensation can cause dramatic amounts of rain or snow to fall – on average, 25 times the flow of the mouth of the Mississippi River.
These rivers of moisture can rapidly turn around drought conditions, but they also carry with them risks of extreme flooding, which is only expected to become more pronounced with more extreme climate change.
The details collected with this program will help prepare future climate models, said Dr. Marty Ralph, UC San Diego’s Scripps Institution of Oceanography meteorologist and founding director of CW3E.
“If you want to predict where a car is going to be five minutes from now you need to know where it’s starting from and how fast it’s moving,” Ralph said.
“Similarly, if there is an atmospheric river out near Hawaii, and we want to forecast where it will hit the California coast a few days later and how strong it is, we need to get out there and take direct measurements.”
The car analogy works for more dimensions than just location and speed, said Anna Wilson.
“Where’s that car now? How big is it, how fast is it driving — that kind of stuff,” she said.
AR Recon plans to expand further west across the Pacific, running test flight operations from Guam for a two-week period this year.
Article updated at 8:45 PM, Nov. 29, 2023.
