TRIN1 (Trinity, CA, Lat. 40.7864, Long. -122.8046, Alt. 1007) Print-Friendly Version Print-Friendly Version (B&W)
2 year and 3 month aerosol data are available in Trinity during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 30.0 Mm-1 (Visual Range ~ 130 Km; Deciview ~ 11.0). The average PM2.5 mass concentration is 3.7 mg/m3. The average contributions of the major aerosol components to Trinity haze are particulate sulfate 16.7%, nitrate 9.1%, organic matter (OMC) 27.9%, elemental carbon (light absorbing carbon, LAC) 6.6%, fine soil 1.6% and coarse mass (CM) 4.8%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 1997-2002) (B&W)
Figure 2 Average contributions of major aerosol chemical components to light extinction in 20% best, middle 60% and 20% worst days (Based on data available in 1997-2002) (Data Table) (B&W)
As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 52.6 Mm-1, which is about 11.5 times of the value of 4.6 Mm-1 during the 20% best days and 3.7 times of the value of 14.2 Mm-1 during the middle 60% days. OMC is the largest contributor to aerosol light extinction, with a contribution of 50% in the 20% worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in August and September, in which ~ 60% of the sampling days are the 20% haziest days at Trinity. As shown in Figure 4, OMC is the largest aerosol contributor to haze during the 20% worst days in August and September, with a contribution of 68% and 38% during the 20% worst days. OMC is the largest aerosol contributor in July and November as well. Nitrate is the largest aerosol contributor to haze in the winter and sulfate is the largest contributor from March to June. Both OMC and sulfate contribute 26% to haze in the 20% worst days in October.
Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 1997-2002) (Data Table) (B&W)
Figure 4 Average contributions of major aerosol chemical components to light extinction during 20% worst days in each month (Based on data available in 1997-2002) (Data Table) (B&W)
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