Estimated error of temperature and salinity analysis.

Analysis errors were computed for value of analyzed temperature and
salinity at every grid and at every depth of the analysis domain. The
computation of the error is based on the theory of objective analysis
and the details are found in Ishii et al. (2003, MWR).

The value of the error is given as relative errors to the standard
deviation of monthly temperature deviation from climatology. Therefore, 
it takes a value from zero to one and the smaller means more
reliable. If you need absolute errors, you may multiply the standard
deviations of WOA provided by NODC/NOAA, for example. The same
standard deviation are used in our objective analysis. 

Why we use relative errors rather than the absolute values is because
observed standard deviations are rather noisy and because the former
can be regarded as the effective number of observations.

Ishii