Multiple integrations of an atmospheric general circulation model (AGC
M) exhibit differences in the decadal mean of the surface heat flux, Q
. The differences (typically 2-3 Wm(-2)) can be as large as 10 Wm(-2)
in places, which are shown to produce sea-surface temperature (SST) ch
anges up to approximately 0.5 degrees C in a hybrid coupled atmosphere
/ocean/sea-ice model or HCM. This underscores a significant mechanism
by which long-lived SST anomalies can arise, independent of any intern
al ocean variability, for which there is very little predictive capabi
lity. Consequently, AGCM integrations using prescribed SSTs provide up
per bounds on the predictability of atmospheric variability. The HCM i
s used to estimate the magnitude of the drift in the climatology of co
upled models if flux adjustments are based on AGCM integrations of dec
adal duration. The random interannual fluctuations in Q averaged over
the ocean are most closely associated with fluctuations in surface lat
ent heating and long wave radiation to space. The same fluctuations ar
e not associated with land surface variability. The impact of variabil
ity in other fluxes on SST in the HCM was also analysed. Changes due t
o wind-stress were approximately half those due to heating, while chan
ges due to freshwater forcing were relatively unimportant except at po
lar latitudes.