The Stratosphere in the MERRA-2 Reanalysis

The Modern-Era Retrospective analysis for Research and Application, Version 2 (MERRA-2) dataset includes numerous advances in the representation of stratospheric features when compared to MERRA and other previous reanalyses. This presentation cover several features that lead to improvements in MERRA-2 compared to MERRA. These include: (a) beneficial impacts of the cubed-sphere model grid on the representation of cross-polar flow; (b) enhanced radiance modeling for the Stratospheric Sounding Units, that leads to better representation of middle and upper stratospheric temperatures in the 1980s; (c) a judicious choice of Solar Backscattered Ultraviolet Version 2 (SBUV2) instruments for ozone that leads to a more consistent record; (d) use of the EOS-Aura Microwave Limb Sounder (MLS) temperature profile retrievals that substantially improves the representation of upper stratospheric temperatures; (e) use of EOS-Aura MLS ozone that leads to realistic vertical ozone gradients in the lower stratosphere and upper troposphere and to a full depiction of the seasonal cycle of ozone in the polar regions; (f) model and analysis improvements that lead to a more realistic representation of the quasi-biennial oscillation and the associated anomalies in the residual circulation. These improvements mean that the stratosphere in MERRA-2 has many very realistic characteristics, representing a substantial advance over MERRA.