Scientists link California droughts, floods to distinctive atmospheric waves.
"This wave pattern is a global dynamic system that sometimes makes droughts or floods in California more likely to occur," said NCAR scientist Haiyan Teng, lead author of the California paper.
The California study was published in the Journal of Climate while the comprehensive study into the wave patterns is appearing in the Journal of the Atmospheric Sciences.
When they do, the result can be persistent weather patterns that often lead to droughts, floods, and heat waves.
The different windows into the atmosphere and precipitation patterns revealed that the formation of a ridge by the California coast is associated with the emergence of the distinctive wavenumber-5 pattern, which guides rain-producing low-pressure systems so that they travel well north of California.
Clues to seasonal weather patterns Forecasters who predict seasonal weather patterns have largely looked to shifting sea surface temperatures in the tropical Pacific, especially changes associated with El Niño and La Niña.
First, however, scientists need to better understand why and when the wave pattern emerges.
In the paper published in Journal of the Atmospheric Sciences, Branstator and Teng explored the physics of the wave pattern.
Using a simplified computer model of the climate system to identify the essential physical processes, the pair found that wavenumber-5 forms when strong jet streams act as wave guides, tightening the otherwise meandering Rossby wave into the signature configuration of five highs and five lows.
"The jets act to focus the energy," Branstator said.