Temperature above the surface layer

Three published data sets of upper-air global temperatures, two from radiosondes and one from satellites, are examined and compared for the lower stratosphere and troposphere. The global lower stratosphere exhibits a downward trend for the past 16+ years of -0.53 degrees C (-0.33 degrees C per decade). Since the 1960's (using radiosondes before 1979 which are subject to known and unknown inhomogeneities) it is likely that there has been a downward trend of about the same magnitude. Significant issues of the stratospheric radiosonde data are: (1) that the long-term time series is biased toward spurious cooling; and (2) the earliest years of Angell display unrealistic variability. Inhomogeneities in satellite data due to orbit drifting and instrument calibration are examined. The tropospheric temperature has shown a downward trend of -0.11 degrees C since 1979 (-0.07 degrees C per decade). Beginning in earlier years, (relying only on radiosonde data before 1979) the estimated warming trend since the late 1950's is +0.07 to +0.11 degrees C per decade. Tropospheric and surface temperature anomalies are compared. There is concern that the disproportionate representation of extratropical continents, with their high temperature variance, may bias any long term 'global' surface trend toward a maximum-possible value than would be calculated had all regions (including those with much lower responsiveness) been monitored.