2011), A comparison of extratropical cyclones in recent reanalyses ERA-Interim

• Fig. 2 shows the largest spatial differences occur between the older JRA-25 reanalysis when compared with the newer high resolution reanalyses (ERA-Interim) (top), particularly in the SH as shown for the older reanalyses in previous studies4. • Differences between the newest reanalyses are small in both hemispheres (bottom) and generally not significant except in some common regions associated with cyclogenesis (not shown). This is a major improvement in the SH, possibly associated with the improved data assimilation. • NASA MERRA shows similar results to the NCEP-CFSR comparison for spatial differences. 3.3 Cyclone intensity • Fig. 3 shows the 925hPa max wind intensity distributions. • Intensities are generally related to spatial resolution except for NASA MERRA, which has larger wind intensities, which is believed is associated with the assimilation of scatterometer winds. • The MSLP distributions (not shown) also show deeper storms for NASA MERRA, while for ξ850 (not shown) the maximum intensity distributions are closely tied to resolution for this small scale field.