Southern Hemisphere ACE
The typical season runs from October through April of the following austral summer and autumn. Overall, the SH accounts for about 25% of global tropical cyclone ACE, which has been relatively stable since 1979. The evolution of El Ninos and La Ninas is of course critical to the frequency and intensity of SH (and NH) tropical cyclones.
Figure. The ratio of SH to global tropical cyclone ACE based upon 24-month running sums. The ratio has remained
relatively stable during the past 30-years which is also reflective of the stability of Northern Hemisphere TC ACE.
This is remarkable, and was pointed out in my latest GRL paper on Northern Hemisphere Tropical Cyclone ACE.
