Table 1. Correlation Coefficient Between UV Flux and Summer PC1 for 1948-2004a 

	Variance of PC1 for the Extended Summer	Correlation for the Extended Summer	  May	  June	  July	  August	  September
10 hPa	  73%	-0.26  (28)	-0.19 (24)	-0.21 (23)	-0.32 (24)	-0.36 (27)	-0.22 (27)
30 hPa	  68%	-0.34  (32)	-0.33 (33)	-0.30 (31)	-0.39 (29)	-0.41 (31)	-0.29 (31)
50 hPa	  58%	-0.38  (35)	-0.37  7(41)	-0.34 (35)	-0.44 (32)	-0.44 (33)	-0.29 (30)
70 hPa	  47%	-0.40  (38)	-0.39 (42)	-0.36 (36)	-0.45 (34)	-0.44 (38)	-0.35 (30)
150 hPa	  18%	-0.35  (40)	-0.34 (41)	-0.30 (33)	-0.41 (33)	-0.37 (37)	-0.31 (30)
300 hPa 	  8.5%	0.12  (47)	0.00  (43)	0.10 (38)	0.27 (47)	0.18 (49)	0.06 (42)

aBold numbers are correlations with statistical confidence level of 95% or higher. The effective sample size is listed in parentheses in each case.