Updated on February 11, 2014
This past weekend, an intense storm caused by an atmospheric river hit the California coast, bringing much-needed rain and snow to the northern part of the state. NOAA scientists and researchers from Scripps Institute of Oceanography aboard NOAA Gulfstream IV aircraft released 52 dropsondes over the Pacific Ocean during two successful research flights on Friday and Saturday. Dropsondes are small parachuted devices that measure atmospheric conditions, such as pressure, temperature, humidity, wind speed and direction.
Atmospheric rivers are narrow conveyor belts of water vapor that can extend thousands of miles. They can bring beneficial water supply and snowpack to the West Coast as well as create conditions for dangerous floods that threaten lives and property.
Animation of Atmospheric River
NOAA animation of the atmospheric river that hit northern California the weekend of Feb 8 and 9, 2014. (NOAA ESRL Physical Sciences Division)
More than five feet of snow fell in the Sierra Nevada Mountains, and as much as 12 inches of rain fell at lower elevations over the weekend. The Russian River, north of San Francisco, went from a trickle to flowing more than 9,000 cubic feet per second within a 24 hour period. Forecasters anticipate another atmospheric river, focusing more on the Oregon and Washington coasts, will hit later this week.
“We will be looking at the structure and evolution of atmospheric rivers,” said lead researcher Chris Fairall of NOAA’s Earth System Research Laboratory (ESRL). “One big atmospheric river can be the difference between drought and flood at a given location. Water and pollution managers, farmers, and skiers all want good precipitation forecasts but the uncertainty is dominated by intensity and landfall location of atmospheric rivers.”
Researchers from ESRL and Scripps Institute for Oceanography are studying atmospheric rivers to help provide better information for earlier extreme weather forecasts. The scientists are also looking at how climate change may be affecting atmospheric rivers.
Researchers are releasing this dropsonde sensor into the atmospheric river to measure air temperature, humidity and other characteristics. (NOAA/ Jeff Smith)
Aboard the G-IV, researchers are releasing small parachuted devices, called dropsondes, across an atmospheric river over the Pacific Ocean. The dropsondes measure atmospheric conditions, such as pressure, temperature, humidity, wind speed and direction, and transmit the information back to the aircraft where a flight scientist uses it to guide the mission. After the dropsonde data is analyzed and processed, the information is put in a standard format established by the World Meteorological Organization and provided to NOAA’s National Hurricane Center to be included in global and local-scale weather prediction models.
The G-IV will also use its tail Doppler radar to map precipitation and wind. The radar data were successfully incorporated into weather prediction models for the first time during the 2013 Atlantic hurricane season. NOAA’s G-IV is operating out of Travis Air Force Base in California for this project. The aircraft is permanently based at the NOAA Aircraft Operations Center, located at MacDill Air Force Base in Tampa, Fla.
Results from this study will help guide atmospheric river research for the upcoming CalWater 2 experiment, which begins in 2015 and will use land-based stations and a research ship as well as multiple aircraft.
For more information contact:
Monica Allen, NOAA Communications @NOAA Research, 301-734-1123, or by email at firstname.lastname@example.org