Figure 3- 13 October 2001 sample departures (measured in standard deviations) of various meteorological fields from their
                 mean background state for this day. Shown are: (a) moisture (given as 700 mb specific humidity) (b) temperature
                (given as 500 mb temperature) (c) geopotential height (given as 850 mb height) and (d) wind (given as mean sea-level
                 pressure).