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Weminuche Wilderness Area Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at WEMI1 based on light extinction coefficient data from 1994 to 2003. No significant trend is found for total aerosol light extinction in 20% worst days. But a significant decrease trend in sulfate light extinction coefficients and a significant increase in nitrate extinction coefficients are found in 20% worst days. Significant decrease in total aerosol light extinction coefficients are found in both middle 60% and 20% best days.

Table 1. Number of valid measurements used in the trends analysis
Site Year StartDate EndDate NoMeas
WEMI1 1994 1/1/1994 12/31/1994 94
WEMI1 1995 1/4/1995 12/30/1995 97
WEMI1 1996 1/17/1996 12/28/1996 83
WEMI1 1997 1/1/1997 12/31/1997 96
WEMI1 1998 1/3/1998 12/26/1998 95
WEMI1 1999 1/6/1999 12/29/1999 94
WEMI1 2000 1/1/2000 12/29/2000 83
WEMI1 2001 1/1/2001 12/30/2001 121
WEMI1 2002 1/11/2002 12/28/2002 110
WEMI1 2003 1/9/2003 12/29/2003 116
Table 2. Trends analysis for 20% worst visibility days
Site Year Bep (1/Mm) Sulfate_Ext (1/Mm) Nitrate_Ext (1/Mm) OMC_Ext (1/Mm) LAC_Ext (1/Mm) Soil_Ext (1/Mm) CM_Ext (1/Mm)
WEMI1 1994 19.95 7.88 0.59 5.08 2.14 0.89 3.38
WEMI1 1995 19.87 8.28 0.62 4.89 2.67 0.78 2.63
WEMI1 1996 20.93 7.39 0.76 6.57 2.94 0.80 2.46
WEMI1 1997 19.88 8.54 0.85 4.05 2.02 0.79 3.63
WEMI1 1998 22.40 9.39 0.93 5.80 2.50 0.76 3.03
WEMI1 1999 20.60 6.75 1.02 5.99 2.36 1.00 3.48
WEMI1 2000 21.08 6.58 1.27 7.21 2.95 0.69 2.39
WEMI1 2001 18.23 7.23 1.06 4.56 2.03 1.25 2.11
WEMI1 2002 30.28 5.16 1.68 14.79 3.04 1.68 3.93
WEMI1 2003 25.56 5.71 1.90 10.65 2.33 1.44 3.53
               
Slope (1/Mm/Year)   0.489 -0.260 0.128 0.583 0.016 0.077 0.017
S-Value   17 -23 43 19 5 15 3
P-Value   0.078 0.023 0.000 0.054 0.364 0.108 0.431

Table 3. Trends analysis for middle 60% visibility days
Site Year Bep (1/Mm) Sulfate_Ext (1/Mm) Nitrate_Ext (1/Mm) OMC_Ext (1/Mm) LAC_Ext (1/Mm) Soil_Ext (1/Mm) CM_Ext (1/Mm)
WEMI1 1994 13.59 4.80 0.64 2.81 1.66 0.62 3.07
WEMI1 1995 11.14 4.16 0.63 2.27 1.64 0.56 1.87
WEMI1 1996 11.14 3.75 0.55 2.92 1.43 0.64 1.85
WEMI1 1997 12.38 4.86 0.59 2.72 1.53 0.40 2.28
WEMI1 1998 12.26 4.62 0.72 3.08 1.54 0.50 1.79
WEMI1 1999 11.29 3.93 0.59 2.92 1.60 0.50 1.74
WEMI1 2000 11.56 4.52 0.74 3.04 1.74 0.35 1.17
WEMI1 2001 10.99 4.51 0.76 2.47 1.49 0.48 1.27
WEMI1 2002 11.09 3.60 1.07 2.81 1.34 0.60 1.68
WEMI1 2003 10.89 3.37 0.72 3.38 1.34 0.50 1.58
               
Slope (1/Mm/Year)   -0.194 -0.087 0.021 0.052 -0.026 -0.013 -0.099
S-Value   -23 -21 19 13 -19 -11 -31
P-Value   0.023 0.036 0.054 0.146 0.054 0.190 0.002

Table 4. Trends analysis for 20% best visibility days
Site Year Bep (1/Mm) Sulfate_Ext (1/Mm) Nitrate_Ext (1/Mm) OMC_Ext (1/Mm) LAC_Ext (1/Mm) Soil_Ext (1/Mm) CM_Ext (1/Mm)
WEMI1 1994 7.50 2.91 0.73 1.56 1.12 0.23 0.95
WEMI1 1995 5.91 1.57 0.70 1.22 0.91 0.25 1.26
WEMI1 1996 5.61 1.70 0.36 1.45 0.79 0.25 1.07
WEMI1 1997 6.68 2.29 0.31 1.53 1.07 0.28 1.20
WEMI1 1998 6.05 2.23 0.25 1.33 0.79 0.28 1.17
WEMI1 1999 5.43 1.53 0.34 1.35 1.04 0.27 0.90
WEMI1 2000 6.06 2.37 0.54 1.32 0.77 0.20 0.85
WEMI1 2001 5.38 1.91 0.32 1.28 0.93 0.23 0.71
WEMI1 2002 5.37 1.85 0.51 1.30 0.77 0.17 0.76
WEMI1 2003 5.11 1.49 0.42 1.44 0.87 0.19 0.71
               
Slope (1/Mm/Year)   -0.188 -0.058 -0.027 -0.016 -0.018 -0.008 -0.052
S-Value   -29 -13 -9 -13 -15 -13 -29
P-Value   0.005 0.146 0.242 0.146 0.108 0.146 0.005

Page last updated 30 March 2005