WaterAtmospheric rivers, cloud-creating aerosol particles, and California water situation
In the midst of the California rainy season, scientists – using aircraft, research vessel, and ground stations — are embarking on a field campaign designed to improve the understanding of the natural and human-caused phenomena that determine when and how the state gets its precipitation. They will do so by studying atmospheric rivers, meteorological events that include the famous rainmaker known as the Pineapple Express. Atmospheric rivers, which produce up to 50 percent of California’s precipitation and can transport 10-20 times the flow of the Mississippi River.
In the midst of the California rainy season, scientists are embarking on a field campaign designed to improve the understanding of the natural and human-caused phenomena that determine when and how the state gets its precipitation. They will do so by studying atmospheric rivers, meteorological events that include the famous rainmaker known as the Pineapple Express.
CalWater 2015 is an interagency, interdisciplinary field campaign which started 14 January 2015. CalWater 2015 will entail four research aircraft flying through major storms while a ship outfitted with additional instruments cruises below. A Scripps release reports that the research team includes scientists from Scripps Institution of Oceanography at UC San Diego, the Department of Energy’s Pacific Northwest National Laboratory, NOAA, and NASA and uses resources from the DOE’s Atmospheric Radiation Measurement (ARM) Climate Research Facility — a national scientific user facility.
The study will help provide a better understanding of how California gets its rain and snow, how human activities are influencing precipitation, and how the new science provides potential to inform water management decisions relating to drought and flood.
“After several years in the making by an interdisciplinary science team, and through support from multiple agencies, the CalWater 2015 field campaign is set to observe the key conditions offshore and over California like has never been possible before,” said Scripps climate researcher Marty Ralph, a CalWater lead investigator. “These data will ultimately help develop better climate projections for water and will help test the potential of using existing reservoirs in new ways based on atmospheric river forecasts.”
Like land-based rivers, atmospheric rivers carry massive amounts of moisture long distances — in California’s case, from the tropics to the U.S. West Coast. When an atmospheric river hits the coast, it releases its moisture as precipitation. How much and whether it falls as rain or snow depends on aerosols — tiny particles made of dust, sea salt, volatile molecules, and pollution.
The researchers will examine the strength of atmospheric rivers, which produce up to 50 percent of California’s precipitation and can transport 10-20 times the flow of the Mississippi River. They will also explore how to predict when and where atmospheric rivers will hit land, as well as the role of ocean evaporation and how the ocean changes after a river passes.
