Interpreting differential temperature trends at the surface and in the lower troposphere
Estimated global-scale temperature trends at Earth's surface (as recorded by thermometers) and in the lower troposphere (as monitored by satellites) diverge by up to 0.14 degrees C per decade over the period 1979 to 1998. Accounting for differences in the spatial coverage of satellite and surface measurements reduces this differential, but still leaves a statistically significant residual of roughly 0.1 degrees C per decade. Natural internal climate variability alone, as simulated in three state-of-the-art coupled atmosphere-ocean models, cannot completely explain this residual trend difference. A model forced by a combination of anthropogenic factors and volcanic aerosols yields surface-troposphere temperature trend differences closest to those observed.
Santer
BD
Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. National Center for Atmospheric Research, Boulder, CO 80307, USA. NOAA Air Resources Laboratory, Silver Spring, MD 20910,
Wigley
TM
Gaffen
DJ
Bengtsson
L
Doutriaux
C
Boyle
JS
Esch
M
Hnilo
JJ
Jones
PD
Meehl
GA
Roeckner
E
Taylor
KE
Wehner
MF