Big COHA logo
           
COHA Overview What's new on COHA COHA tour COHA site map Contact COHA staff
 
   Analysis by state
   Analysis by class I
   Analysis by region
   Descriptive maps
   Backtrajectories
   Trends analysis
   PMF Modeling
   Episode analysis
   Dust analysis
   Tribal analysis
   Fish & Wildlife
   Terms & acronyms
For best results,
please use:
Internet Explorer 5
(or higher)
Netscape 6
(or higher)
more info...
Great Basin National Park Trends Analysis
The tables and figures below show the trends analysis results for 20% worst, middle 60% and 20% best days at GRBA1 based on light extinction coefficient data from 1994 to 2003. Overall, there is no significant  trend in aerosol light extinction in 20% worst days. No significant trends are found for aerosol light extinction coefficients in middle 60% days and 20% best days as well. Nitrate extinction increased in the 20% worst days and decreased in the 20% best days.

Table 1. Number of valid measurements used in the trends analysis
Site Year StartDate EndDate NoMeas
GRBA1 1994 1/5/1994 12/31/1994 95
GRBA1 1995 1/4/1995 12/30/1995 102
GRBA1 1996 1/3/1996 12/28/1996 100
GRBA1 1997 1/1/1997 12/31/1997 100
GRBA1 1998 1/3/1998 12/30/1998 97
GRBA1 1999 1/2/1999 12/29/1999 95
GRBA1 2000 1/1/2000 12/29/2000 94
GRBA1 2001 1/1/2001 12/30/2001 115
GRBA1 2002 1/2/2002 12/31/2002 119
GRBA1 2003 1/6/2003 12/29/2003 103
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)
GRBA1 1994 18.85 5.32 0.64 5.48 1.39 1.62 4.39
GRBA1 1995 16.53 5.10 0.69 4.33 2.16 1.01 3.25
GRBA1 1996 24.45 4.49 1.14 10.55 3.31 1.27 3.69
GRBA1 1997 18.50 5.42 1.64 5.19 2.17 0.82 3.26
GRBA1 1998 19.91 5.10 1.68 6.86 2.49 1.06 2.72
GRBA1 1999 21.38 4.25 1.46 8.50 3.04 1.29 2.84
GRBA1 2000 21.63 4.56 1.06 7.64 2.28 1.36 4.74
GRBA1 2001 19.76 5.71 1.72 5.11 1.91 1.62 3.69
GRBA1 2002 25.21 4.07 1.31 9.65 2.04 1.57 6.57
GRBA1 2003 18.39 4.85 1.46 6.36 1.93 0.90 2.89
               
Slope (1/Mm/Year)   0.266 -0.060 0.083 0.254 -0.029 0.017 0.004
S-Value   9 -9 19 7 -5 7 3
P-Value   0.242 0.242 0.054 0.300 0.364 0.300 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)
GRBA1 1994 12.43 3.28 0.73 3.93 1.52 0.64 2.32
GRBA1 1995 10.29 2.51 0.74 2.89 1.71 0.51 1.93
GRBA1 1996 10.89 2.72 0.71 3.29 1.38 0.56 2.23
GRBA1 1997 9.81 3.00 0.61 2.94 1.16 0.41 1.69
GRBA1 1998 12.02 2.93 0.50 4.20 1.61 0.41 2.37
GRBA1 1999 12.24 3.17 0.62 4.28 1.66 0.76 1.75
GRBA1 2000 10.99 2.80 0.90 3.95 1.35 0.41 1.58
GRBA1 2001 10.68 3.57 0.98 2.82 1.17 0.57 1.56
GRBA1 2002 11.06 2.92 1.04 3.40 1.28 0.64 1.79
GRBA1 2003 9.59 2.56 0.84 3.36 1.09 0.39 1.37
               
Slope (1/Mm/Year)   -0.103 -0.002 0.035 0.003 -0.044 -0.006 -0.074
S-Value   -9 -1 15 1 -21 -9 -25
P-Value   0.242 0.500 0.108 0.500 0.036 0.242 0.014

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)
GRBA1 1994 7.37 1.77 0.86 2.07 1.10 0.29 1.29
GRBA1 1995 5.04 1.18 0.82 1.39 0.65 0.16 0.85
GRBA1 1996 5.00 1.22 0.62 1.37 0.66 0.15 0.98
GRBA1 1997 5.28 1.57 0.36 1.83 0.64 0.20 0.69
GRBA1 1998 6.17 1.51 0.39 2.27 1.07 0.19 0.75
GRBA1 1999 6.53 1.57 0.29 2.23 1.02 0.44 0.99
GRBA1 2000 5.95 1.59 0.38 2.51 0.90 0.16 0.40
GRBA1 2001 5.09 1.51 0.42 1.43 0.64 0.21 0.87
GRBA1 2002 4.32 1.24 0.31 1.28 0.67 0.21 0.60
GRBA1 2003 4.63 1.24 0.32 1.62 0.55 0.18 0.72
               
Slope (1/Mm/Year)   -0.114 -0.017 -0.053 -0.014 -0.017 0.002 -0.056
S-Value   -15 -5 -25 -1 -15 3 -17
P-Value   0.108 0.364 0.014 0.500 0.108 0.431 0.078

Page last updated 30 March 2005