Articles | Volume 35, issue 2
Regular paper
27 Feb 2017
Regular paper |  | 27 Feb 2017

Comparison of the long-term trends in stratospheric dynamics of four reanalyses

Michal Kozubek, Peter Krizan, and Jan Lastovicka

Abstract. Since the long-term trends of different atmospheric parameters have been already studied separately in many papers, this study is focused on the stratospheric wind (zonal and meridional components) and temperature over the whole globe at 10 hPa during 1979–2015. We present the trends for the whole winter (October–March), for each individual month of winter and separately for the period before and after the ozone trend turnaround during the mid-1990s. The change of ozone trends has a clear impact on trends in other investigated stratospheric parameters. Four reanalyses (MERRA, ERA-Interim, JRA-55 and NCEP-DOE) are used for comparison. Every grid point is analysed, not zonal averages. The comparison of trends in meridional wind, which is closely connected with Brewer–Dobson circulation, shows a good agreement for all four reanalyses (main features and amplitudes of the trends) in terms of winter averages, but there are some differences in individual months, particularly in trend amplitude. These results could be important for studying dynamics (transport) in the whole stratosphere.

Short summary
A study of trends in the middle stratosphere using comparisons of four main reanalyses (ERA-Interim, JRA-55, MERRA and NCEP/NCAR). We identified that all four reanalyses show very similar trends on a season or monthly basis. We also compute trends for each grid point not as a zonal mean. This approach shows detailed features in the trend studies in both hemispheres.