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Yosemite National Park Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at YOSE1 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 increase trend in nitrate light extinction coefficients is found in 20% worst days. A significant decrease in total aerosol light extinction coefficients is found in 20% best days.

Table 1. Number of valid measurements used in the trends analysis
Site Year StartDate EndDate NoMeas
YOSE1 1994 1/1/1994 12/31/1994 93
YOSE1 1995 1/4/1995 12/16/1995 93
YOSE1 1996 1/17/1996 12/18/1996 87
YOSE1 1997 1/1/1997 12/27/1997 92
YOSE1 1998 1/14/1998 12/30/1998 93
YOSE1 1999 1/2/1999 12/25/1999 90
YOSE1 2000 1/1/2000 12/29/2000 84
YOSE1 2001 1/1/2001 12/30/2001 105
YOSE1 2002 1/2/2002 12/31/2002 115
YOSE1 2003 1/3/2003 12/29/2003 112
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)
YOSE1 1994 36.58 8.60 2.06 17.61 4.24 1.03 3.05
YOSE1 1995 34.76 8.66 2.01 14.73 4.22 1.03 4.12
YOSE1 1996 54.08 7.71 3.00 29.38 8.03 0.95 5.00
YOSE1 1997 39.03 8.29 6.36 14.68 3.34 1.32 5.03
YOSE1 1998 37.53 11.01 4.53 13.40 3.70 1.30 3.60
YOSE1 1999 68.68 7.00 4.85 44.64 9.33 0.98 1.88
YOSE1 2000 46.44 9.77 12.62 13.83 4.71 0.56 4.96
YOSE1 2001 40.60 8.93 7.34 15.40 4.13 1.22 3.59
YOSE1 2002 57.29 8.57 9.51 28.86 5.30 0.83 4.21
YOSE1 2003 46.74 7.12 5.98 24.21 5.16 0.61 3.65
               
Slope (1/Mm/Year)   1.129 -0.085 0.754 0.178 0.118 -0.029 -0.003
S-Value   19 -5 27 3 7 -15 -1
P-Value   0.054 0.364 0.008 0.431 0.300 0.108 0.500

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)
YOSE1 1994 16.50 4.58 2.62 5.25 1.53 0.41 2.11
YOSE1 1995 19.79 5.30 2.35 6.67 2.17 0.56 2.73
YOSE1 1996 21.75 5.62 2.22 8.24 2.39 0.63 2.66
YOSE1 1997 19.10 4.88 2.27 7.09 1.75 0.58 2.53
YOSE1 1998 19.11 5.20 2.09 7.25 2.11 0.40 2.06
YOSE1 1999 22.86 6.07 2.36 9.07 2.45 0.54 2.36
YOSE1 2000 18.75 5.68 2.90 5.97 1.96 0.37 1.88
YOSE1 2001 18.27 5.67 2.74 5.49 1.72 0.52 2.13
YOSE1 2002 21.62 6.05 2.81 7.66 1.85 0.63 2.64
YOSE1 2003 19.55 5.78 2.61 6.96 1.85 0.35 2.01
               
Slope (1/Mm/Year)   0.075 0.133 0.049 0.101 -0.019 -0.007 -0.074
S-Value   3 25 13 5 -5 -11 -15
P-Value   0.431 0.014 0.146 0.364 0.364 0.190 0.108

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)
YOSE1 1994 7.57 1.27 2.96 1.47 0.51 0.10 1.26
YOSE1 1995 8.24 1.40 3.16 1.21 0.64 0.11 1.72
YOSE1 1996 7.44 1.46 1.76 1.76 0.78 0.12 1.56
YOSE1 1997 6.72 1.27 0.45 3.01 0.57 0.09 1.32
YOSE1 1998 5.37 1.23 0.49 2.10 0.35 0.11 1.09
YOSE1 1999 6.44 1.67 0.60 2.63 0.77 0.16 0.61
YOSE1 2000 4.91 1.89 0.38 1.47 0.53 0.11 0.53
YOSE1 2001 3.51 1.31 0.63 0.61 0.29 0.14 0.52
YOSE1 2002 4.70 1.56 0.82 1.19 0.46 0.09 0.59
YOSE1 2003 4.11 1.45 0.53 1.37 0.35 0.07 0.34
               
Slope (1/Mm/Year)   -0.505 0.024 -0.215 -0.056 -0.031 -0.002 -0.162
S-Value   -37 13 -13 -11 -17 -5 -35
P-Value   0.000 0.146 0.146 0.190 0.078 0.364 0.000

Page last updated 30 March 2005