1995 Integrated Monitoring Study: Fog measurements in the Northern San Joaquin Valley - preliminary results
- Colorado State Univ., Fort Collins, CO (United States); and others
Vertical gradients in fog chemistry and physics were measured from a 430 m television broadcast tower in the northern San Joaquin Valley near Walnut Grove, California. Fog was collected on the ground and at two elevations on the tower using Caltech Active Strand Cloudwater Collectors Version 2 (CASCC2). Work was conducted as part of the 1995 Integrated Monitoring Study (IMS95). Results will be used to evaluate the need to make measurements aloft in future regional studies of fog processing of atmospheric particles and for testing whether vertically resolved fog models provide realistic simulations of fog physics and chemistry above the ground. Two fog/low cloud events were sampled during the tower study. Preliminary results show concentrations of major species in the fogwater typically decreasing with altitude, while liquid water contents increase. Fogwater loadings of major species, the total amount of a species in the aqueous phase per unit air volume, were observed to increase with altitude. Major species concentrations were typically quite stable at a given elevation, while significant decreases were observed over time in liquid water content. Fogwater concentrations of soluble hydroperoxides were highest near the surface and increased with time after sunrise and were observed to coexist in the high pH fog with S(IV). Time lapse video footage of the top of the fog/cloud layer revealed a very dynamic interface, suggesting entrainment of material from the clear air into the fog/cloud may be significant. 12 refs., 7 figs.
- OSTI ID:
- 617654
- Report Number(s):
- CONF-9605175-; TRN: 98:002112-0035
- Resource Relation:
- Conference: International symposium on measurement of toxic and related air pollutants, Research Triangle Park, NC (United States), 7-10 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of Measurement of toxic and related air pollutants; PB: 889 p.
- Country of Publication:
- United States
- Language:
- English
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