Figure 8.4: Second-order
statistics of surface air temperature, sea level pressure and precipitation simulated
by CMIP2 model control runs. The radial co-ordinate gives the magnitude of total
standard deviation, normalised by the observed value, and the angular co-ordinate
gives the correlation with observations. It follows that the distance between
the OBSERVED point and any model's point is proportional to the r.m.s model
error (see Section 8.2). Numbers indicate models counting
from left to right in the following two figures. Letters indicate alternate observationally
based data sets compared with the baseline observations: e = 15-year ECMWF reanalysis
("ERA"); n = NCAR/NCEP reanalysis. From Covey et al. (2000b).