TUXE1 (Tuxedni, AK, Lat. 59.9917, Long. -152.6333, Alt. 10)         

1 year and 1 month aerosol data are available in Tuxedni during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 21.2 Mm-1 (Visual Range ~ 184 Km; Deciview ~ 7.5). The average PM2.5 mass concentration is 2.0 mg/m3. The average contributions of the major aerosol components to Tuxedni haze are particulate sulfate 24.1%, nitrate 5.5%, organic matter (OMC) 13.6%, elemental carbon (light absorbing carbon, LAC) 3.2%, fine soil 0.5% and coarse mass (CM) 6.0%. 

Bext = 21.2 Mm-1

Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 1997-2002)

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)

As Figure 2 indicates, the average aerosol light extinction coefficient (Bext – Rayleigh Scattering (10 Mm-1)) during the 20% worst days is 25.6 Mm-1, which is about 9.4 times of the value of 2.7 Mm-1 during the 20% best days and 2.8 times of the value of 9.1 Mm-1 during the middle 60% days. Sulfate and OMC are the largest contributors to aerosol light extinction, with a contribution of 39% and 34% in the 20% worst days.

Figure 3 suggests that the highest occurrence of the 20% worst days happened in July, in which ~ 50% of the sampling days are the 20% haziest days at Tuxedni. As shown in Figure 4, sulfate is the largest aerosol contributor to haze during the 20% worst days from May to September, with a contribution of 25 - 38% during the 20% worst days. OMC is the largest aerosol contributor in October, and Nitrate is the largest one in November, both with a contribution of 66% in the 20% worst days in October and November, respectively. Both OMC and sulfate contribute 20% to haze in the 20% worst days in December.

Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 1997-2002)

 

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)