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Point Reyes Wilderness Area Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at PORE1 based on light extinction coefficient data from 1994 to 2003. A significant increase trend in nitrate light extinction coefficients, and a significant decrease trend in sulfate light 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 caused mainly by decrease in nitrate light extinction coefficients.

Table 1. Number of valid measurements used in the trends analysis
Site Year StartDate EndDate NoMeas
PORE1 1994 1/1/1994 12/31/1994 96
PORE1 1995 1/18/1995 12/23/1995 80
PORE1 1996 1/10/1996 12/28/1996 88
PORE1 1997 1/1/1997 12/27/1997 68
PORE1 1998 1/21/1998 12/30/1998 78
PORE1 1999 1/2/1999 12/29/1999 80
PORE1 2000 1/1/2000 12/23/2000 81
PORE1 2001 1/4/2001 12/30/2001 73
PORE1 2002 2/4/2002 12/28/2002 86
PORE1 2003 1/3/2003 12/29/2003 98
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)
PORE1 1994 52.65 21.62 7.88 12.49 6.13 0.29 4.24
PORE1 1995 49.90 26.11 7.25 6.75 3.04 0.30 6.45
PORE1 1996 53.08 23.61 10.38 8.47 3.08 0.39 7.15
PORE1 1997 68.08 22.22 26.70 10.50 3.10 0.30 5.26
PORE1 1998 54.87 19.15 15.12 10.80 3.46 0.44 5.89
PORE1 1999 84.04 23.68 28.79 19.50 5.31 0.59 6.17
PORE1 2000 50.69 17.07 15.79 8.46 2.99 0.48 5.90
PORE1 2001 82.63 19.86 40.74 9.12 3.30 0.29 9.33
PORE1 2002 97.58 17.75 53.01 16.02 3.61 0.57 6.61
PORE1 2003 47.54 17.86 14.20 7.04 1.88 0.35 6.21
               
Slope (1/Mm/Year)   3.188 -0.760 3.132 0.036 -0.039 0.024 0.182
S-Value   11 -21 25 1 -5 15 15
P-Value   0.190 0.036 0.014 0.500 0.364 0.108 0.108

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)
PORE1 1994 28.77 12.21 7.04 3.20 0.95 0.18 5.20
PORE1 1995 27.91 11.92 7.10 3.28 1.15 0.17 4.28
PORE1 1996 27.48 11.68 5.80 3.37 0.82 0.22 5.57
PORE1 1997 26.22 12.30 3.78 3.74 0.75 0.19 5.45
PORE1 1998 25.40 11.54 4.56 3.52 0.81 0.19 4.77
PORE1 1999 28.19 12.48 4.76 3.75 0.93 0.20 6.07
PORE1 2000 25.61 11.05 5.12 3.09 1.00 0.16 5.18
PORE1 2001 23.87 11.64 4.32 2.29 0.73 0.16 4.73
PORE1 2002 27.03 12.86 4.96 3.07 0.77 0.32 5.05
PORE1 2003 23.30 11.03 3.79 2.90 0.66 0.18 4.73
               
Slope (1/Mm/Year)   -0.527 -0.081 -0.288 -0.047 -0.029 -0.001 -0.052
S-Value   -27 -9 -19 -13 -21 -1 -9
P-Value   0.008 0.242 0.054 0.146 0.036 0.500 0.242

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)
PORE1 1994 17.79 5.59 7.33 1.38 0.51 0.10 2.88
PORE1 1995 17.30 5.19 7.33 1.86 0.83 0.08 2.01
PORE1 1996 14.85 5.53 4.07 2.22 0.71 0.08 2.24
PORE1 1997 13.36 5.58 2.39 2.26 0.72 0.07 2.34
PORE1 1998 13.65 5.44 1.75 2.24 0.35 0.11 3.76
PORE1 1999 13.90 6.51 1.55 2.18 0.44 0.09 3.12
PORE1 2000 12.84 5.19 2.12 1.48 0.57 0.09 3.38
PORE1 2001 11.68 5.75 1.86 1.11 0.58 0.07 2.30
PORE1 2002 13.06 6.48 2.05 1.42 0.31 0.11 2.70
PORE1 2003 12.34 6.32 2.06 0.66 0.28 0.07 2.94
               
Slope (1/Mm/Year)   -0.602 0.093 -0.420 -0.079 -0.040 -0.001 0.076
S-Value   -33 13 -23 -17 -21 -7 11
P-Value   0.001 0.146 0.023 0.078 0.036 0.300 0.190

Page last updated 30 March 2005