NOAA Studies Atmospheric ‘Rivers’ Using Unmanned Aircraft
February 10, 2011
NOAA scientists will use unmanned aircraft to study “rivers in the sky” during the Winter Storms and Pacific Atmospheric Rivers, or WISPAR, field campaign slated to begin Feb. 11. The focus of the research is to improve our understanding of how atmospheric rivers form and behave, and to evaluate the operational use of unmanned aircraft for investigating these phenomena.
Atmospheric rivers, or ARs, are narrow regions in the atmosphere that transport large amounts of water vapor across the Pacific and other regions. In one day, an average AR transports an amount of water vapor equivalent to a foot of liquid water covering 10 million acres — an area roughly the size of Maryland. This is about seven times the average daily flow of water from the Mississippi River into the Gulf of Mexico. Only a portion of the water vapor transported by an AR is transformed into rain or snow; for example, about 20-40 percent in one AR crossing northern California makes it to the surface.
The importance of ARs was recently highlighted in a major emergency preparedness scenario led by the U.S. Geological Survey that focused on the possibility of a series of strong ARs striking California. That scenario showed that resulting flooding, wind and even mudslides could exceed damages brought on by Hurricane Katrina in 2005.
Results from WISPAR will include demonstration of new technology, contributions to the science of ARs, and, through collaborations with NOAA’s Winter Storms Reconnaissance Program — started by the National Weather Service in 1999 to collect observations to improve winter storm forecasts — the potential of offshore monitoring of ARs to aid in weather predictions.