Correction to satellite based temperature record changes cooling trend to a warming trend
E. S. Takle
A controversy has existed the past several years over whether or not
the earth's atmosphere is warming. Data taken from thermometers near
the earth's surface reveal a quite convincing warming trend of about
0.5 K over the last 100 years. On the other hand, data from Satellites
suggest the lower atmosphere is cooling, not warming. Wentz and
Schabel (1998) report that corrections to satellite-based temperature
measurements are needed to account for the slow decrease in altitude
that satellites normally experience due to drag. Spencer and Christy
(1990, 1992) and Christy et al. (1994) reported a 17-year cooling trend
in satellite (microwave sounding unit, MSU) temperature of - 0.05 K
per decade globally at 3.5 km. As the satellite falls toward earth,
its field of view changes and produces a reading representative of a
more limited area. The corrected temperature calculated by Wentz and
Schabel (1998) for the period analyzed by Spencer and Christy is +0.07
K per decade, which is much more consistent with the observed rise in
global surface temperature of 0.13 K per decade (Houghton, 1996) over
this 17-year period.
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