WIMO1 (Wichita Mountains NWR, OK, Lat. 34.7323, Long. -98.713, Alt. 509) Print-Friendly Version Print-Friendly Version (B&W)
IMPROVE sampling started on 3/5/2001 at Wichita Mountains NWR. Therefore, no complete aerosol data is available in 2001. Based on the regional haze rule version 2, 3 years of complete aerosol data (2002-2004) are available in Wichita Mountains NWR during the baseline period of 2000 - 2004. The "Guidance for tracking progress under the regional haze rule" states that "if maximum data recovery is not achieved, EPA believes that a minimum of 3 years of data meeting these completeness requirements is sufficient to calculate the 5-year averages within each 5-year period". As shown in Figure 1, the overall average total light extinction coefficient (Bext) at Wichita Mountains NWR is 60.8 Mm-1 (Visual Range ~ 84 Km; Deciview ~ 17). The average PM2.5 mass concentration is 7.7 mg/m3. The average contributions of the major aerosol components to Wichita Mountains haze are particulate sulfate 37.3%, nitrate 17.5%, organic matter (OMC) 14.3%, elemental carbon (light absorbing carbon, LAC) 4.3%, fine soil 1.3%, sea salt 0.2%, and coarse mass (CM) 6.9%.
Figure 1 Average contributions of major aerosol chemical components to light extinction (Based on data available in 2002-2004) (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 2002-2004) (Data Table) (B&W)
As Figure 2 indicates, the average light extinction coefficient during the 20% worst days is 111.2 Mm-1, which is about 4.1 times of the value of 26.9 Mm-1 during the 20% best days and 2.0 times of the value of 54.8 Mm-1 during the middle 60% days. Sulfate is the largest aerosol contributor to light extinction during the 20% worst days, with a contribution of ~ 44%. Nitrate and OMC also contribute about 21% and 16%, respectively to light extinction during the 20% worst visibility days.
Figure 3 suggests that the highest occurrence of the 20% worst days happened in September, in which ~ 40% of the sampling days are the 20% haziest days at Wichita Mountains. As shown in Figure 4, in the 20% worst visibility days, sulfate is the largest aerosol contributor to haze during the warm seasons, while nitrate is the largest aerosol contributor during the cool seasons. One worst day was observed in July 2004 during the 2002-2004 sampling period, with OMC being the largest aerosol contributor (~40%) to light extinction.
Figure 3 Percentage of sampling days that are 20% worst days in each month (Based on data available in 2002-2004) (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 2002-2004) (Data Table) (B&W)
List of Tables:
1. Number of measurements available in each month during 2002-2004
4. Percentage of worst days happened in each month based on data available during 2002-2004
