Figure 12.9: (a) Observed
surface air temperature trends for 1949 to 1997. (b) Simulated surface air temperature
trends for the same period as estimated from a five-member greenhouse gas plus
sulphate ensemble run with the GFDL R30 model. (c) Observed trends (in colour)
that lie outside the 90% natural variability confidence bounds as estimated from
the GFDL R30 control run. Grey areas show regions where the observed trends are
consistent with the local 49-year temperature trends in the control run. (d) As
for (c) but showing observed 1949 to 1997 trends (in colour) that are significantly
different (as determined with a t-test at the 10% level) from those simulated
by the greenhouse gas plus aerosol simulations performed with the GFDL R30 model
(from Knutson et al., 2000). The larger grey areas in (d) than (c) indicate that
the observed trends are consistent with the anthropogenic forced simulations over
larger regions than the control simulations.
