Vinnikov et al. (1996)
Vinnikov, Konstantin Ya., Alan Robock, Ronald J. Stouffer and Syukuro Manabe,
1996: Vertical patterns of free and forced climate variations.
Geophys. Res. Lett., 23, 1801-1804.
ABSTRACT:
Observations of the vertical structure of atmospheric
temperature changes over the past three decades show that
while the global-average lower atmosphere has warmed, the
upper troposphere and lower stratosphere have cooled. While
these changes resemble model calculations of the expected
changes due to observed anthropogenic increases of
greenhouse gases, decreases of lower stratospheric ozone,
and increases of tropospheric aerosols, the changes may also
have been caused by natural unforced internal fluctuations of
the climate system. Here we use the results of a 1000-year
simulation from a mathematical model of the coupled
ocean-atmosphere-land system performed without any changes
in external forcing, so that we may consider its variations as a
surrogate for free, internally-generated, natural fluctuations of
the climate system. When the global mean surface air
temperature is warm in the model, the lower troposphere,
upper troposphere and lower stratosphere are also warm over
most of the Earth, in contrast to the observations of the last
three decades and to model simulations of the forced climate
response due to increased greenhouse gases. The observed
temperature change of the past three decades is therefore
unlikely to have been caused by natural internal variations of
the climate system, thereby strengthening the argument that
these changes can be attributed to anthropogenic activities.
Prepared by Alan Robock (robock@envsci.rutgers.edu ) -
Last updated on April 21, 1999