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Tonto National Monument Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at TONT1 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 mainly by increase in nitrate, soil and CM extinctions. 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
TONT1 1994 1/1/1994 12/31/1994 98
TONT1 1995 1/4/1995 12/9/1995 98
TONT1 1996 1/10/1996 12/28/1996 98
TONT1 1997 1/1/1997 12/31/1997 94
TONT1 1998 1/3/1998 12/30/1998 98
TONT1 1999 1/2/1999 12/18/1999 98
TONT1 2000 2/16/2000 12/29/2000 86
TONT1 2001 1/1/2001 12/21/2001 114
TONT1 2002 1/2/2002 12/31/2002 108
TONT1 2003 1/3/2003 12/29/2003 105
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)
TONT1 1994 28.74 9.24 1.54 8.41 3.45 1.51 4.59
TONT1 1995 34.55 10.90 1.55 10.36 4.55 1.12 6.06
TONT1 1996 33.22 10.10 1.61 8.30 3.40 1.46 8.35
TONT1 1997 30.59 11.31 1.69 7.13 2.60 1.38 6.47
TONT1 1998 34.07 11.35 2.34 9.31 3.94 1.28 5.84
TONT1 1999 37.17 7.07 2.97 13.21 4.65 1.63 7.65
TONT1 2000 35.85 8.29 4.00 9.46 2.46 2.99 8.65
TONT1 2001 32.32 8.03 3.03 8.52 3.18 1.86 7.71
TONT1 2002 36.34 9.15 3.29 10.75 3.32 2.80 7.02
TONT1 2003 40.93 7.22 3.87 11.26 3.10 4.42 11.06
               
Slope (1/Mm/Year)   0.798 -0.357 0.281 0.293 -0.043 0.223 0.396
S-Value   23 -15 39 17 -13 27 23
P-Value   0.023 0.108 0.000 0.078 0.146 0.008 0.023

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)
TONT1 1994 18.98 6.40 1.51 4.46 2.45 0.80 3.36
TONT1 1995 20.75 6.50 1.43 5.03 2.64 0.91 4.22
TONT1 1996 20.42 6.30 1.32 4.32 1.95 1.09 5.43
TONT1 1997 19.23 7.11 1.24 3.91 2.03 0.79 4.16
TONT1 1998 19.83 6.25 1.63 5.05 2.27 0.84 3.80
TONT1 1999 20.38 6.19 1.29 5.49 2.43 0.81 4.17
TONT1 2000 21.45 6.81 1.88 5.85 2.01 1.40 3.50
TONT1 2001 17.69 6.00 1.80 4.07 1.69 0.91 3.22
TONT1 2002 19.97 6.07 1.84 4.58 1.72 1.43 4.32
TONT1 2003 19.52 5.64 1.76 4.63 2.26 1.34 3.88
               
Slope (1/Mm/Year)   -0.062 -0.062 0.046 0.041 -0.053 0.051 -0.034
S-Value   -3 -25 15 7 -17 19 -5
P-Value   0.431 0.014 0.108 0.300 0.078 0.054 0.364

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)
TONT1 1994 10.92 3.35 1.58 2.60 1.38 0.36 1.66
TONT1 1995 12.18 3.22 1.61 2.93 1.71 0.42 2.30
TONT1 1996 11.65 3.54 1.25 2.63 1.51 0.46 2.26
TONT1 1997 10.81 3.36 0.67 2.80 1.28 0.50 2.20
TONT1 1998 10.34 2.90 0.75 2.74 1.30 0.49 2.15
TONT1 1999 12.36 3.07 1.02 3.76 1.77 0.45 2.30
TONT1 2000 10.52 3.71 0.82 2.69 1.54 0.27 1.49
TONT1 2001 10.77 3.62 1.32 2.70 1.18 0.46 1.49
TONT1 2002 10.21 3.53 0.98 2.13 1.36 0.55 1.66
TONT1 2003 10.09 2.83 1.18 2.56 1.17 0.60 1.75
               
Slope (1/Mm/Year)   -0.142 -0.002 -0.044 -0.036 -0.026 0.018 -0.053
S-Value   -25 -1 -7 -11 -15 19 -15
P-Value   0.014 0.500 0.300 0.190 0.108 0.054 0.108

Page last updated 30 March 2005