Table 2. The Fitting Parameters for the 5-Line Average and P1(1) in Summer and Winter (Equation (1))a			
	a, 1012 cm-2	b, min.	c, 1013 cm-2
5-Line Average			
Summer	-1.12 +/- 0.01	26.0 +/- 0.7 	7.14 +/- 0.01
Winter	-1.14 +/- 0.03	36.0 +/- 1.8	5.04 +/- 0.02
P1(1)			
Summer	-1.13 +/- 0.02	28.0 +/- 1.4	7.05 +/- 0.03
Winter	-1.19 +/- 0.06	34.0 +/- 3.1	4.87 +/- 0.03
aUncertainties are two standard deviations.