What may we conclude about global tropospheric temperature trends?



[1] Three realizations of the atmospheric temperature representing the layer from the surface to about 18 km generated from microwave emissions were published in 2003. Their 1979–2002 linear trends were stated as +0.24 ± 0.02, +0.12 ± 0.02 and +0.03 ± 0.05°C decade−1. Because the upper portion of this layer includes the stratosphere, the opportunity to utilize radiosonde measurements as an independent assessor of these trend values is diminished. However, the University of Alabama in Huntsville (UAH) also produces a lower tropospheric temperature (LT) product (0–8 km, trend of +0.08°C decade−1) for which radiosondes are much more suitable. Comparisons of this UAH product with radiosonde-simulated layer temperatures show no significant difference in LT trends, lending support for the least positive trend of the three deeper layer values (+0.03 ± 0.05°C decade−1) as it was constructed in the same manner as LT.