TITLE:
The Recent Droughts of 2019/20 in Southern Africa and Its Teleconnection with ENSO Events
AUTHORS:
Berhanu F. Alemaw
KEYWORDS:
Rainfall Variability, Drought, ENSO Episode, Correlation Analysis, Southern Africa
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.12 No.2,
March
14,
2022
ABSTRACT: This study is motivated to highlight the variability
of recent drought hotspots in the region of southern Africa in terms of the
seasonal and annual rainfall regimes and their possible spatial linkage with
the 1950-2020 seasonal El Niño/Southern Oscillation (ENSO). Some evidence is
found on possible links between the occurrence of drought hotspots in the
region in terms of seasonal and mean annual runoff and warm ENSO events. This
was revealed by the existence of a strong and nearly-strong positive linear correlation between Seasonal and
annual rainfall depths and the warm seasonal ENSO indices explained by the
southern oscillation index represented by the sea level pressure (SLP)
anomalies data obtained from the National Oceanographic and Aeronautics Administration
(NOAA). Considering the entire southern African region, 41% of the surface areas exhibit moderate (r > 0.25) and
strong (r > 0.5)
correlation coefficients in terms
of the December to February quarter rainfall and ENSO indices. Above 50%
confidence interval in the correlation between seasonal rainfall and ENSO
during DJF quarters is found in 74% of the surface area of the region of
southern Africa. The high confidence interval of the positive correlation
coefficients is an indication that substantial variance of precipitation during
ENSO years is accounted for by the warm ENSO events. The areas with pronounced
lower rainfalls and droughts associated with ENSO activity in the region
include larger and some pockets of various countries in southern Africa,
including but not limited to Angola, Botswana, Lesotho, Namibia, Zambia,
Zimbabwe, South Africa and Mozambique. The recent drought events of 2019/2020,
and previously in 2015/16 in this region with wider regional impacts can be
explained by the ENSO phenomena.