A new NASA study has concluded California accumulated a debt of about 20 inches of precipitation between 2012 and 2015 – the average amount expected to fall in the state in a single year. The deficit was driven primarily by a lack of air currents moving inland from the Pacific Ocean that are rich in water vapor.
In an average year, 20 to 50 percent of California’s precipitation comes from relatively few, but extreme events called atmospheric rivers that move from over the Pacific Ocean to the California coast. “When they say that an atmospheric river makes landfall, it’s almost like a hurricane, without the winds. They cause extreme precipitation,” said study lead author Andrey Savtchenko at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Savtchenko and his colleagues examined data from 17 years of satellite observations and 36 years of combined observations and model data to understand how precipitation has varied in California since 1979. The results were published Thursday in the Journal of Geophysical Research: Atmospheres, a journal of the American Geophysical Union. ∞∞∞∞∞ SEE MORE ∞∞∞∞∞