THRO1 (Theodore Roosevelt, ND, Lat. 46.8948, Long. -103.3776, Alt. 853) Print-Friendly Version Print-Friendly Version (B&W)
3 year and 1 month aerosol data are available in Theodore Roosevelt during the sampling period of 1997 - 2002. As shown in Figure 1, the overall average total light extinction coefficient (Bext) is 37.3 Mm-1 (Visual Range ~ 105 Km; Deciview ~ 13.2). The average PM2.5 mass concentration is 4.2 mg/m3. The average contributions of the major aerosol components to Theodore Roosevelt haze are particulate sulfate 29.4%, nitrate 15.7%, organic matter (OMC) 11.5%, elemental carbon (light absorbing carbon, LAC) 4.6%, fine soil 2.0% and coarse mass (CM) 10.0%.
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 50.3 Mm-1, which is about 4.2 times of the value of 12.1 Mm-1 during the 20% best days and 2.1 times of the value of 24.4 Mm-1 during the middle 60% days. Sulfate and nitrate are two of the largest contributors to aerosol light extinction, with a contribution of 41% and 29% in the 20% worst days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in January, in which ~42% of the sampling days are the 20% haziest days at Theodore Roosevelt. As shown in Figure 4, Nitrate and sulfate are the largest aerosol contributors to haze during the 20% worst days in January, with a contribution of 38% and 36% during the 20% worst days. Both sulfate and nitrate are important haze contributors in the cool season from January to March and October to December. Their contributions are 30 - 45% and 25 - 40% during the 20% worst days. Sulfate is the largest aerosol contributor to haze from April to July, with a contribution of 30 - 35%. Both sulfate and OMC contribute 25 - 30% to haze in August and September.
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)
