Downstream development during ridging South Atlantic Ocean anticyclones

Abstract Ridging South Atlantic high pressure systems (ridging highs) are often accompanied by cut-off low (COL) aloft, but may also occur without them, in which case a linear baroclinic wave would be observed propagating across the African domain upper troposphere. Using 41 years of ERA-5 reanalysis data, this study documents differences between characteristics prevailing dynamical processes and associated local eddy kinetic energy generation, its downstream transfer dissipation during these two scenarios. The shows that when COLs present then conversion is strong it confined east Greenwich Meridian, whereas located Africa much weaker, ridging occurs COLs. strength locations with differing jet streak configurations scenarios; lead to Rossby breaking absence thereof there COLs, respectively. presence leads trans-ridge development facilitates from midlatitudes into domain. When no present, trans-trough stronger than upstream ridge. Barotropic mean further highs. difference identified can traced back potential vorticity anomaly structures, largely due whether waves break or do not evolution events