GRCA2 (Hance Camp at Grand Canyon NP, AZ, Lat. 35.9731, Long. -111.984, Alt. 2267) Print-Friendly Version Print-Friendly Version (B&W)
5 years aerosol data are available in Hance Camp at Grand Canyon NP during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 23.8 Mm-1 (Visual Range ~ 164 Km; Deciview ~ 8.7). The average PM2.5 mass concentration is 3.1 mg/m3. The average contributions of the major aerosol components to Hance Camp at Grand Canyon NP haze are particulate sulfate 18.7%, nitrate 4.8%, organic matter (OMC) 16.0%, elemental carbon (light absorbing carbon, LAC) 4.5%, fine soil 3.0% and coarse mass (CM) 10.9%.
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 23.8 Mm-1, which is about 4.6 times of the value of 5.2 Mm-1 during the 20% best days and 1.8 times of the value of 13.1 Mm-1 during the middle 60% days. OMC is the largest contributor to aerosol light extinction, with a contribution of 31% in the 20% worst days. Sulfate also contributes ~28% in the worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in June and September during which ~ 40% of the sampling days are the 20% haziest days at Hance Camp at Grand Canyon NP. As shown in Figure 4, in June, CM is the largest aerosol contributor to haze, with a contribution of 19.6% during the 20% worst days. Sulfate and OMC particles contribute 16.5% and 15.8% respectively. In September, sulfate and OMC are responsible for 25.3% and 24.9% of the light extinction during the 20% worst days, and are two of the largest contributors to aerosol light extinction.
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)
