Fig. 9. Decadal trends in specific humidity for HadCRUH versus
HadISDH over the 1973–2003 period of record. Trends have been
estimated using the median of pairwise slopes (Sen, 1968; Lanzante,
1996) method. Where intervals defined by the 95% confidence
limits on the median of the slopes are both of the same sign
as the median trend presented in the grid boxes, the trend is presumed
to be significantly different from a zero trend. This is indicated
by a black dot within the grid box. This means that there is
higher confidence in the direction of the trend, but not necessarily
the magnitude. The spread of the confidence interval provides
the confidence in the magnitude; these values are available online
at www.metoffice.gov.uk/hadobs/hadisdh. Note non-linear colour
bars.