| The southern-Hemisphere Spring season is characterised by a shift of
the global tropical circulation from the northern-Hemisphere monsoon
systems to the seasonal southern-Hemisphere ITCZ, and the concomitant
intensification of inter-annual variability associated with the ENSO
and its teleconnections. While large body of work has been devoted to a
better understanding of the evolution of interannual anomalies, and of
the underlying progression of the seasonal circulation near the
Equator, a truly global picture of the climatological transition between
the two summer-hemisphere circulation regimes has only recently started
to emerge. Taking inspiration from a study of the meteorology of the
South-East Pacific during Spring 2008, in this paper we discuss the
mechanisms involved in the seasonal march of the southern-Hemisphere
circulation during southern Spring. We highlight the scale
relationships involved, the important role played by changing
teleconnection in shaping this evolution, and their alteration or
disruption associated with the growth of ENSO anomalies. |