The relationships of upper tropospheric water vapor
(UTWV), cloud ice and sea surface temperature (SST) are
examined in the annual cycles of ECMWF analyses and
simulations from 15 atmosphere-ocean coupled models
which were contributed to the IPCC AR4. The results are
compared with the observed relationships based on UTWV
and cloud ice measurements from MLS on Aura. It is shown
that the ECMWF analyses produce positive correlations
between UTWV, cloud ice and SST, similar to the MLS
data. The rate of the increase of cloud ice and UTWV with
SST is about 30% larger than that for MLS. For the IPCC
simulations, the relationships between UTWV, cloud ice
and SST are qualitatively captured. However, the
magnitudes of the simulated cloud ice show a
considerable disagreement between models, by nearly a
factor of 10. The amplitudes of the approximate linear
relations between UTWV, cloud ice and SST vary by a
factor up to 4. Citation: Su, H., D. E. Waliser, J. H. Jiang, J. Li,
W. G. Read, J. W. Waters, and A. M. Tompkins (2006),
Relationships of upper tropospheric water vapor, clouds and SST:
MLS observations, ECMWF analyses and GCM simulations,
Geophys. Res. Lett., 33, L22802, doi:10.1029/2006GL027582

Last Updated: 2007-07-27