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Project at a Glance

Project Status: complete

Report Published March 1989:

Title: Characterization of cloud chemistry and frequency of canopy exposure to clouds in the Sierra Nevada : final report submitted to California Air Resources Board

Principal Investigator / Author(s): Hoffmann, Michael R

Contractor: W. M. Keck Laboratories, California Institute of Technology

Contract Number: A6-185-32

Research Program Area: Atmospheric Processes

Topic Areas: Acid Deposition


Interception of cloudwater by forests in the Sierra Nevada may contribute significantly to acid deposition in the region. Cloudwater sampled in Sequoia National Park had pH values ranging from 4.4 to 5.7. The advance of cold fronts into the Park appears to lead to higher aerosol and gas phase concentrations than are seen under normal mountain/valley circulations, producing higher cloudwater concentrations than might otherwise be expected. Estimates of annual deposition rates of NO3- SO42-, NH4+and H- due to cloudwater impaction are comparable to those measured in precipitation.


For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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