The Bolivian, Botswana, and Bilybara Highs and Southern Hemisphere drought/floods

Semipermanent anticyclones in the midlevel troposphere over the subtropical landmasses are a prominent component of Southern Hemisphere climate. Typically, they occur over Bolivia, Botswana/Namibia, and northwestern Australia from austral spring to about April and are strongest in late summer. Here a mode of variability is studied that modulates the strength of these midlevel anticyclones and which is not strongly tied to El Nino-Southern Oscillation. This mode leads to variations in January-March rainfall over large parts of South America, southern Africa, and Australia on both interannual and near-decadal scales.