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Jarbidge Wilderness Area Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at JARB1 based on light extinction coefficient data from 1994 to 2003. Overall, there is no significant  trend in aerosol light extinction in 20% worst days. Nitrate extinctions increased significantly, while LAC extinctions decreased significantly in the worst days. Aerosol light extinction coefficients decreased significantly in  20% best days.

Table 1. Number of valid measurements used in the trends analysis
Site Year StartDate EndDate NoMeas
JARB1 1994 1/1/1994 12/31/1994 88
JARB1 1995 1/4/1995 12/23/1995 92
JARB1 1996 1/3/1996 10/12/1996 80
JARB1 1997 4/30/1997 12/27/1997 60
JARB1 1998 1/3/1998 12/30/1998 90
JARB1 1999 1/6/1999 12/29/1999 93
JARB1 2000 1/1/2000 12/29/2000 69
JARB1 2001 1/1/2001 12/30/2001 104
JARB1 2002 1/2/2002 12/31/2002 83
JARB1 2003 1/3/2003 12/29/2003 106
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)
JARB1 1994 30.39 4.02 0.56 14.76 2.61 2.38 6.07
JARB1 1995 20.72 4.12 0.56 7.25 1.89 1.47 5.43
JARB1 1996 31.53 4.48 0.91 12.51 3.08 2.72 7.82
JARB1 1997 22.97 4.59 0.77 7.21 3.44 1.13 5.84
JARB1 1998 24.67 4.07 0.68 8.09 1.76 2.67 7.40
JARB1 1999 28.21 4.43 1.14 11.61 2.97 2.45 5.60
JARB1 2000 25.24 4.62 1.00 10.68 2.44 1.82 4.68
JARB1 2001 26.82 4.71 1.08 9.19 2.33 2.85 6.66
JARB1 2002 25.08 3.65 2.31 10.32 1.68 3.03 4.09
JARB1 2003 24.43 4.57 0.80 9.19 1.61 1.92 6.34
               
Slope (1/Mm/Year)   -0.270 0.046 0.077 -0.300 -0.112 0.063 -0.157
S-Value   -5 13 25 -7 -21 11 -9
P-Value   0.364 0.146 0.014 0.300 0.036 0.190 0.242

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)
JARB1 1994 12.07 3.26 0.70 3.21 0.78 1.01 3.11
JARB1 1995 9.56 2.76 0.70 2.73 0.95 0.54 1.89
JARB1 1996 12.40 3.16 0.65 3.87 1.01 0.82 2.89
JARB1 1997 12.31 2.78 0.45 3.81 0.75 0.75 3.77
JARB1 1998 11.09 3.56 0.74 3.09 0.99 0.51 2.20
JARB1 1999 11.20 2.87 0.67 2.88 0.88 0.91 2.99
JARB1 2000 8.02 2.60 0.62 2.58 0.81 0.36 1.06
JARB1 2001 10.16 3.53 0.99 2.56 0.74 0.61 1.74
JARB1 2002 9.25 2.72 0.69 2.67 0.72 0.65 1.78
JARB1 2003 10.32 2.64 0.89 3.24 0.74 0.60 2.23
               
Slope (1/Mm/Year)   -0.296 -0.048 0.011 -0.067 -0.023 -0.031 -0.110
S-Value   -17 -13 9 -15 -21 -13 -13
P-Value   0.078 0.146 0.242 0.108 0.036 0.146 0.146

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)
JARB1 1994 5.50 1.88 0.86 1.40 0.26 0.13 0.97
JARB1 1995 4.43 1.16 0.82 1.29 0.50 0.12 0.54
JARB1 1996 4.83 1.54 0.87 1.19 0.33 0.17 0.73
JARB1 1997 6.41 1.47 0.43 1.70 0.35 0.37 2.09
JARB1 1998 4.32 1.66 0.29 1.15 0.42 0.18 0.63
JARB1 1999 2.99 1.23 0.27 0.51 0.33 0.16 0.51
JARB1 2000 2.90 1.29 0.28 0.65 0.33 0.09 0.26
JARB1 2001 3.49 1.65 0.42 0.76 0.33 0.10 0.22
JARB1 2002 2.98 1.26 0.23 0.81 0.31 0.07 0.30
JARB1 2003 3.18 1.15 0.36 1.00 0.32 0.08 0.27
               
Slope (1/Mm/Year)   -0.278 -0.046 -0.058 -0.073 -0.004 -0.012 -0.076
S-Value   -25 -15 -25 -19 -15 -21 -27
P-Value   0.014 0.108 0.014 0.054 0.108 0.036 0.008

Page last updated 30 March 2005