The Consistency of Modeled and Observed Temperature Trends in the Tropical Troposphere: A Comment on Santer et al (2008)

TL;DR

This paper re-evaluates the consistency between climate model predictions and observed temperature trends in the tropical troposphere, revealing significant discrepancies with recent data that were not apparent in earlier studies.

Contribution

It applies the methodology of Santer et al. (2008) to updated data, demonstrating that previous conclusions about model-observation agreement no longer hold.

Findings

Significant discrepancies found in recent UAH and RSS satellite data.

Model-observation differences are evident in lapse rate trends.

Earlier agreement reported in 2008 is not supported with current data.

Abstract

Santer et al (2008) (S08) compared climate models and observations in the tropical troposphere and reported that "there is no longer a serious discrepancy between modeled and observed trends in tropical lapse rates." They found no statistically significant differences between modeled (ensemble mean) trends and observed trends at the T2LT and T2 layers, and they found no significant difference between observed and modeled surface-minus-troposphere lapse rates. However they only used data over the 1979-1999 period. Using the S08 methodology on up-to-date data, we find a statistically significant discrepancy between observations and models with respect to trends in the UAH data, as well as lapse rate trends comparing either RSS or UAH to the HADCRUT3v land-ocean surface trend.