Ferrell 00Z pressure 1981 - 988.0 990.2 - 985.2 978.1 987.2 995.5 988.5 981.0 977.1 978.6 1982 990.2 986.9 977.7 980.3 986.7 980.6 989.1 975.1 977.0 980.2 984.4 994.8 1983 992.4 995.1 985.4 979.5 986.2 989.4 981.4 - - - - - 1984 994.3 989.6 979.4 979.8 987.6 980.9 976.2 - 980.8 - - - 1985 - 988.8 987.2 988.2 - - 975.9 985.9 976.8 976.8 - - 1986 - 993.4 992.7 981.8 992.2 991.8 981.7 984.2 979.8 974.4 976.5 982.3 1987 - 989.0 988.0 989.8 984.7 988.5 993.5 976.8 989.3 980.6 - 985.9 1988 989.2 985.6 987.3 984.5 990.9 995.6 - 975.9 984.4 990.5 - 982.7 1989 985.0 986.1 985.0 - - - - - - 975.7 975.7 989.2 1990 988.9 983.1 987.3 993.8 998.6 989.7 999.7 982.6 974.8 983.1 984.9 984.8 1991 983.8 990.0 983.6 988.9 989.1 992.2 - - - - 984.4 995.7 1992 989.2 997.8 988.7 987.1 993.5 996.3 984.5 - - - - - 1993 - 978.5 985.7 981.7 982.8 977.1 971.9 978.6 976.6 976.3 979.1 982.6 1994 984.4 983.0 978.9 985.8 985.1 998.5 989.6 975.0 989.3 977.9 983.9 980.1 1995 980.0 981.3 991.1 983.7 981.4 988.2 1001.1 986.6 978.5 979.8 977.3 977.5 1996 985.9 990.4 985.6 978.9 985.7 982.9 982.6 987.3 989.5 972.5 987.1 985.2 1997 988.5 990.0 980.4 986.3 973.7 987.6 979.8 977.7 981.3 977.2 986.8 990.5 1998 985.6 980.6 982.3 976.6 982.9 977.5 980.7 - - - - - 1999 - 987.3 - - - - - - - - - - 2000 - - - - - - - - - - - - 2001 - 988.3 985.6 980.1 985.0 982.3 986.8 983.4 979.6 972.6 976.3 976.3 2002 983.4 978.0 990.4 981.6 991.9 995.0 989.3 979.3 986.5 989.7 983.8 978.8 2003 - - - - - - - - - - - - 2004 - - - - - - - - - - - - 2005 - - - - - - - - - - - - 2006 - - - - - - - - - - 978.7 983.3 2007 986.1 983.3 989.8 984.9 987.3 985.5 997.1 979.6 978.1 982.2 981.7 975.8 2008 980.1 979.9 984.8 985.9 984.0 976.8 980.4 982.7 972.5 973.9 - - 2009 - - - - - - - - - - - -