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Canyonlands National Park Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at CANY1 based on light extinction coefficient data from 1994 to 2003. Aerosol light extinction coefficients in 20% worst days increased by ~0.5 (1/Mm)/Year and the trend is close to significant (P-value = 0.08), which is due to the increase in nitrate and OMC extinction. There are significant decrease trends in aerosol light extinction in both middle 60% and 20% best days. In the middle 60% days, LAC and CM extinction decreased while nitrate extinction increased significantly. OMC, LAC and CM extinction all decreased significantly in the 20% best visibility days.

Table 1. Number of valid measurements used in the trends analysis 
Site Year StartDate EndDate NoMeas
CANY1 1994 1/12/1994 12/31/1994 96
CANY1 1995 1/4/1995 12/30/1995 87
CANY1 1996 1/3/1996 12/28/1996 92
CANY1 1997 1/1/1997 12/31/1997 99
CANY1 1998 1/3/1998 12/30/1998 102
CANY1 1999 1/2/1999 12/29/1999 98
CANY1 2000 1/1/2000 12/29/2000 98
CANY1 2001 1/1/2001 12/30/2001 107
CANY1 2002 1/5/2002 12/31/2002 109
CANY1 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)
CANY1 1994 22.14 6.39 0.90 5.43 1.41 1.65 6.36
CANY1 1995 19.82 7.31 1.04 4.74 1.98 0.69 4.06
CANY1 1996 25.50 6.41 1.25 8.01 3.09 1.40 5.33
CANY1 1997 23.58 8.74 3.06 3.97 2.01 0.78 5.02
CANY1 1998 23.97 8.15 2.63 5.22 2.08 0.73 5.16
CANY1 1999 22.15 5.98 1.42 5.27 1.95 1.59 5.94
CANY1 2000 23.20 7.62 3.64 5.72 2.09 0.79 3.34
CANY1 2001 22.55 7.84 3.95 4.24 1.53 1.70 3.29
CANY1 2002 27.78 4.74 2.71 9.53 2.00 2.75 6.04
CANY1 2003 27.68 6.36 2.74 9.91 2.16 1.38 5.14
               
Slope (1/Mm/Year)   0.459 -0.104 0.223 0.254 0.017 0.054 -0.050
S-Value   17 -7 27 15 9 13 -7
P-Value   0.078 0.300 0.008 0.108 0.242 0.146 0.300

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)
CANY1 1994 14.91 5.74 1.05 2.96 1.22 0.67 3.28
CANY1 1995 12.36 4.32 1.04 2.32 1.29 0.57 2.82
CANY1 1996 13.81 4.43 0.81 3.24 1.66 0.68 2.99
CANY1 1997 14.59 5.60 0.91 2.54 1.20 0.51 3.83
CANY1 1998 14.10 5.05 0.94 3.48 1.45 0.54 2.65
CANY1 1999 12.24 4.14 0.94 2.78 1.22 0.64 2.53
CANY1 2000 12.04 4.81 1.15 2.74 1.10 0.52 1.73
CANY1 2001 12.70 5.19 1.71 2.44 0.89 0.65 1.82
CANY1 2002 13.39 4.55 1.77 2.61 1.01 1.22 2.22
CANY1 2003 11.02 3.61 1.31 2.52 0.92 0.54 2.13
               
Slope (1/Mm/Year)   -0.240 -0.117 0.066 -0.043 -0.047 0.000 -0.132
S-Value   -21 -13 21 -11 -27 1 -27
P-Value   0.036 0.146 0.036 0.190 0.008 0.500 0.008

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)
CANY1 1994 9.46 3.75 1.14 1.90 0.64 0.28 1.74
CANY1 1995 7.70 2.19 1.19 1.46 0.93 0.26 1.67
CANY1 1996 6.79 2.54 0.73 1.12 0.73 0.19 1.47
CANY1 1997 7.99 2.82 0.53 1.65 0.75 0.27 1.96
CANY1 1998 7.65 2.43 0.59 1.78 0.85 0.35 1.66
CANY1 1999 7.43 2.77 0.50 1.43 0.69 0.32 1.73
CANY1 2000 6.13 2.53 0.46 1.30 0.46 0.22 1.16
CANY1 2001 6.73 2.75 0.66 1.24 0.52 0.44 1.12
CANY1 2002 6.89 2.78 0.87 1.31 0.54 0.44 0.95
CANY1 2003 5.58 2.33 0.63 1.06 0.45 0.21 0.89
               
Slope (1/Mm/Year)   -0.307 -0.008 -0.033 -0.078 -0.041 0.007 -0.098
S-Value   -29 -5 -13 -23 -23 7 -31
P-Value   0.005 0.364 0.146 0.023 0.023 0.300 0.002

Page last updated 30 March 2005