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Rocky Mountain National Park Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at ROMO1 based on light extinction coefficient data from 1994 to 2003. A significant increase trend is found for total aerosol light extinction in 20% worst days, caused by increase in nitrate extinction. A significant increase in nitrate extinction and a significant decrease in sulfate extinction are observed in middle 60% 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
ROMO1 1994 1/1/1994 12/31/1994 97
ROMO1 1995 1/4/1995 12/16/1995 91
ROMO1 1996 1/10/1996 12/21/1996 88
ROMO1 1997 1/1/1997 12/31/1997 99
ROMO1 1998 1/3/1998 12/30/1998 89
ROMO1 1999 1/2/1999 12/18/1999 81
ROMO1 2000 1/5/2000 12/29/2000 107
ROMO1 2001 1/1/2001 12/30/2001 121
ROMO1 2002 1/2/2002 12/31/2002 120
ROMO1 2003 1/3/2003 12/29/2003 117
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)
ROMO1 1994 26.74 8.20 1.23 9.07 2.47 1.30 4.47
ROMO1 1995 26.66 10.24 1.19 6.47 2.84 1.12 4.80
ROMO1 1996 27.72 9.16 2.36 8.84 2.88 1.02 3.47
ROMO1 1997 24.05 9.39 2.25 6.17 2.30 0.73 3.21
ROMO1 1998 28.67 10.32 2.75 8.89 2.86 1.39 2.47
ROMO1 1999 25.66 7.75 3.88 7.36 2.79 1.11 2.78
ROMO1 2000 32.43 7.34 2.72 9.63 2.86 1.28 8.61
ROMO1 2001 31.33 10.87 7.87 5.95 2.08 1.37 3.19
ROMO1 2002 43.82 10.30 8.88 14.29 3.67 1.99 4.68
ROMO1 2003 30.53 7.67 3.52 10.87 2.49 1.12 4.86
               
Slope (1/Mm/Year)   0.779 -0.006 0.520 0.291 0.002 0.030 0.026
S-Value   21 -1 31 11 3 11 3
P-Value   0.036 0.500 0.002 0.190 0.431 0.190 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)
ROMO1 1994 15.12 5.06 1.22 3.55 1.11 0.72 3.46
ROMO1 1995 13.38 5.02 1.23 2.64 1.31 0.57 2.59
ROMO1 1996 13.51 5.19 1.06 3.26 1.52 0.62 1.85
ROMO1 1997 13.50 5.36 0.97 3.11 1.36 0.49 2.23
ROMO1 1998 15.84 5.71 1.25 4.89 1.58 0.63 1.78
ROMO1 1999 12.92 4.49 0.87 4.14 1.34 0.52 1.56
ROMO1 2000 13.63 4.37 2.02 2.99 1.18 0.45 2.63
ROMO1 2001 13.62 4.88 1.59 3.32 1.15 0.77 1.90
ROMO1 2002 14.52 4.70 2.57 3.10 0.98 0.87 2.30
ROMO1 2003 14.29 4.24 2.11 3.84 1.29 0.59 2.22
               
Slope (1/Mm/Year)   0.040 -0.092 0.116 0.033 -0.027 0.003 -0.082
S-Value   7 -19 21 3 -11 3 -9
P-Value   0.300 0.054 0.036 0.431 0.190 0.431 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)
ROMO1 1994 7.47 1.96 1.18 1.69 0.69 0.34 1.60
ROMO1 1995 6.76 1.48 1.22 1.35 1.03 0.22 1.47
ROMO1 1996 4.93 1.48 0.62 1.08 0.76 0.16 0.83
ROMO1 1997 5.34 1.89 0.23 1.24 0.79 0.15 1.05
ROMO1 1998 6.31 2.05 0.39 2.03 0.78 0.14 0.92
ROMO1 1999 4.61 1.65 0.22 1.30 0.61 0.16 0.67
ROMO1 2000 4.58 1.98 0.61 0.87 0.41 0.13 0.58
ROMO1 2001 4.20 1.82 0.33 0.71 0.39 0.19 0.78
ROMO1 2002 3.37 1.12 0.27 0.84 0.35 0.11 0.67
ROMO1 2003 4.16 1.53 0.28 1.21 0.30 0.12 0.74
               
Slope (1/Mm/Year)   -0.373 -0.022 -0.095 -0.075 -0.079 -0.010 -0.094
S-Value   -37 -5 -21 -21 -33 -27 -27
P-Value   0.000 0.364 0.036 0.036 0.001 0.008 0.008

Page last updated 30 March 2005