Intercomparison of Reanalyses Dynamic Variables in the Stratosphere: Results from the SPARC-Reanalysis Intercomparison Project

Abstract:

The Stratospheric-Tropospheric Processes and their Role in Climate (SPARC)-Reanalysis Intercomparison Project (S-RIP) is in the process of generating a multi-chapter report describing the thermal, dynamic, and chemical characteristics of the recent and past reanalyses. This presentation will focus on the basic characteristics of the thermal and dynamic variables (temperatures, heights, winds). In order to not favor any one particular reanalysis, an ensemble mean of the four most recent reanalyses [CFSR, MERRA, ERA-Interim, and the JRA55] has been created. Differences from this ensemble mean indicate how these four reanalyses and previous reanalyses differ in their long term climatology and time evolution of their dynamic variables at both poles and in the tropics. Differences from the ensemble mean indicate issues with how the analysis systems managed data poor time periods, consequences of bias correction, the transition from the SSU to AMSU observing systems, and differences in the annual amplitudes. The RMS of their differences over time indicates that there is an increase in their agreement from 1979 to present with greater agreement occurring in the AMSU time period.