Interpreting Recent Global-Mean Temperature Changes in the Lower Stratosphere Simulated by Climate Models
Thursday, 18 December 2014: 2:10 PM
It has been suggested that state-of-the-art climate models, both with interactive chemistry and without interactive chemistry (CCMVal-2 and CMIP5) do not reproduce the observed lower stratosphere temperature anomalies that are observed by satellite microwave sounding instruments. We find that making two changes in the analysis can eliminate this disagreement. One is a change in the definition of the temperature anomalies as being zero for the 4-year mean (1979-1982) at the beginning of the data and modeling analysis period. Such a definition of the zero temperature anomaly does not take into proper account that observations over a relatively short period represent a single realization of several possible climate states, and thus this zero anomaly definition can be misleading when comparing anomalies from observations and models. The other change is our taking into account all CMIP-5 and CCMVal-2 model runs that ran realistic scenarios for the period 1979-2005. With these two changes in the analysis, we conclude that temperature changes from both CMIP-5 and CCMVal-2 models agree well with MSU-4 observations over the period 1979-2005.