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Task 1:
Refined Tribal Assessments by Region |
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| 1.5 Conclusion |
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| In this task we successfully
revised the previous work by examining data collected from 2000 to 2004.
We also revised the analysis methodology in order to look at the
spatial representativeness in all regions within the WRAP. Similar to
the first effort, the spatial representativeness was based on the six
aerosol species known to be attributed to light extinction; sulfates,
nitrates, organic carbon, elemental carbon, coarse mass, and soil. |
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| Overall the representative
distances decreased by approximately 30 percent compared to the first
assessment including the regions with the default 150 km. If we only
compare those regions that were assessed with enough sites, there was a 14
percent decrease. Possible contributors to the change over time
include, variations in the aerosol compositions from variations due to meteorology,
variations in aerosol composition from emission changes such as frequency of
regional and local fires, and dust events, change in the methodology to
include more sites (minimum 4 sites in each region), changes in the network
(a few new sites started in later years) and updates to the IMPROVE
concentration database. |
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| We also investigated the
effects of removing the Walker River and Spokane tribal sites on regional
representativeness. Removing the Walker River site from the Great Basin
region increased the representative distance by 82 km, an 84 percent jump in
distance. There was little difference in the regional correlation as a
consequence of removing the Spokane site. Representative distance
decreased only by 3 percent without the Spokane site. This indicates that
data collected at the Spokane site correlates well with other sites in the
region over this time period. |
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Last updated 9 November 2007
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