An 'Aerosol Effect' Detected in Winter Orographic Clouds but an Effect on Precipitation Could Not Be Determined


  • Edward Hindman The City College of New York, New York City


Analyses of a 22-year record (1984/85 - 2005/06) of wintertime (December - February) measurements at Storm Peak Laboratory (SPL) in the northern Colorado Rocky Mountains have shown aerosol particle concentrations were directly related to cloud droplet concentrations, the droplet concentrations were inversely related to mean diameters and the mean diameters were not related to the precipitation rates. A direct relationship between mean diameters and precipitation rates was expected due to snow crystal riming; the measurements were too variable to establish a relationship.  Additionally, no significant trends in precipitation rate and snowfall water content were detected; at least a 40-year record is required. Nevertheless, the record defines average wintertime cloud and precipitation properties at SPL.




Scientific Papers