Byrd 12Z pressure 1980 - - 812.9 818.8 817.2 803.1 817.4 811.4 811.0 800.9 816.1 816.8 1981 - 816.8 818.5 813.8 808.4 802.5 805.7 806.0 806.1 806.1 804.3 809.9 1982 821.3 814.1 804.0 798.8 804.7 804.1 807.9 801.2 797.4 801.8 812.5 824.4 1983 820.6 816.7 812.0 808.0 813.3 804.7 799.2 795.6 803.3 794.5 803.2 813.0 1984 821.7 816.8 809.1 808.1 810.6 810.2 793.5 799.4 798.4 807.8 807.3 821.5 1985 820.5 813.3 811.1 808.1 - 806.2 790.5 799.3 796.6 800.0 802.2 809.9 1986 816.7 819.8 814.2 806.7 820.0 812.4 801.5 800.1 793.9 798.3 805.8 812.2 1987 821.6 815.9 804.9 810.1 809.5 811.1 815.4 801.7 808.3 801.3 803.5 816.6 1988 817.6 811.9 - - - - - - - - - - 1989 - - - - - - - - - - - - 1990 - 810.2 810.0 815.8 819.5 802.5 812.1 798.5 794.9 - - - 1991 - 818.2 804.9 808.7 812.7 812.3 811.4 800.0 803.7 804.4 810.4 825.4 1992 818.6 821.7 816.9 808.6 818.4 - - - - - - - 1993 - 810.0 810.0 806.2 - 808.2 801.8 801.5 797.3 801.4 808.1 812.7 1994 - 809.9 804.5 812.6 809.8 818.4 812.0 793.7 806.0 805.9 814.7 815.7 1995 812.9 811.9 814.0 805.8 803.9 818.1 820.1 808.1 801.8 803.3 806.6 809.9 1996 817.3 816.2 807.7 - - - - - - - - - 1997 - 819.4 806.5 806.8 800.3 815.2 803.4 797.7 805.1 809.5 819.3 823.3 1998 815.5 813.6 808.4 799.4 811.3 806.9 801.0 800.0 807.3 804.6 801.2 812.6 1999 814.8 813.4 808.8 803.3 799.0 - - - - - - 805.9 2000 - - - - - 811.0 805.5 809.1 - - - - 2001 - - - - - - - - - - - - 2002 814.4 806.6 818.5 - - - - - - - - 811.1 2003 - - - - - - - - - - - - 2004 - - - - - - - - - - - - 2005 - - - - - - - - - - - - 2006 - - - - - - - - - - - - 2007 - - - 814.4 809.3 811.2 820.2 804.1 - - 814.0 807.2 2008 815.4 811.5 814.3 810.1 807.0 - - - - 803.4 - - 2009 - - - - - - - - - - - -