A comparison of tropical temperature trends with model predictions

Abstract

ABSTRACT:We examine tropospheric temperature trends of 67 runs from 22 'Climate of the 20th Century' model simulations and try to reconcile them with the best available updated observations (in the tropics during the satellite era). Model results and observed temperature trends are in disagreement in most of the tropical troposphere, being separated by more than twice the uncertainty of the model mean. In layers near 5 km, the modelled trend is 100 to 300% higher than observed, and, above 8 km, modelled and observed trends have opposite signs. These conclusions contrast strongly with those of recent publications based on essentially the same data.

Climate, hydrology and freshwater: towards an interactive incorporation of hydrological experience into climate research

“…GCMs reported by IPCC) were not subject to such validation (the term "validation" does not appear in IPCC AR4) and, therefore, the reliability of the outputs of these models, that have been used to assess the impacts on water resources, is not tested. Recent independent studies on the validation of IPCC models (Douglass et al, 2008;Frank, 2008;Koutsoyiannis et al, 2008a) indicate a rather poor performance, especially on long-term (climatic) scales. Solely using different unvalidated models to produce ensembles of climate predictions (or projections, in IPCC's vocabulary), as is current practice in IPCC reports, does not provide a scientific basis for uncertainty estimation.…”

Internal variability in simulated and observed tropical tropospheric temperature trends

“…However, most of the existing studies focus on periods starting after year 1979-the beginning of the satellite era-and analyze just one trend estimate [e.g., Santer et al, 2005;Douglass et al, 2007;Santer et al, 2008;Fu et al, 2011;Po-Chedley and Fu, 2012]. We argue that to put potential trend discrepancies into appropriate context, all overlapping trends over the longest available record of tropical tropospheric temperatures must 10.1002/2017GL073798 be analyzed [Thorne et al, 2007;Risbey et al, 2014;Marotzke and Forster, 2015].…”

What Do Observational Datasets Say about Modeled Tropospheric Temperature Trends since 1979?

“…Pinatubo (1991). In terms of climate change due to increasing greenhouse gases from (primarily) energy production, climate models project a prominent warming of the T LT which in magnitude is on average twice as large near 300-200 hPa as changes projected for the surface [2].…”

“…There have been essentially two groups of publications on this contentious issue, one reporting that trends of T LT in observations and models are statistically not inconsistent with each other (e.g., [4,5]) and the other reporting that model representations are significantly different than observations, thus pointing to the potential for fundamental problems with models (e.g., [2,[6][7][8][9][10].) With the new information noted above, we will look again into this controversy which primarily centers on the acceptance of a magnitude of the T LT trend.…”