NCAR Tech Note TN-373+STR, "Global Analyses from ECMWF and Atlas of 1000 to 10 mb Circulation Statistics", K. Trenberth, 1992.
NCAR Tech Note TN-301, "Intercomparison of NMC and ECMWF Global Analyses: 1980-1986", K. Trenberth and J. Olson, 1988.
