| Precipitation variability over Africa south of the equator is not very well understood and its variability has been poorly documented. Small populations, poor financial resources and relatively complicated meteorological conditions all contribute to our poor understanding of precipitation variability over these regions. The NCEPNCAR reanalysis dataset, a new and unique dataset, is used to analyze the atmospheric circulation, and climatic conditions associated with precipitation variability over southeastern and southern Africa. Strong relationships are found between precipitation receipt and El Niño, and the North Atlantic Oscillation over both southeastern and southern Africa. Regional precipitation indices were constructed to summarize the precipitation receipt at stations significantly correlated to the North Atlantic Oscillation Index over both these regions.; Regression analyses are used to estimate climatic conditions associated with atmospheric circulation and precipitation indices over southeastern and southern Africa. Decreased precipitation is recorded over eastern Mica, and increased precipitation over southern Africa during the positive phase of the North Atlantic Oscillation primarily due to near surface circulation anomalies. Conversely, increased precipitation is recorded over eastern Africa, and decreased precipitation over south Africa during El Niño events, again, principally due to near surface circulation anomalies. Upper level dynamics are examined in relation to precipitation variability; but it is shown that there is no consistent upper level support for near surface level dynamics associated with precipitation variability. Specific humidity, vertically integrated precipitable water and outgoing longwave radiation are also examined in relation to precipitation variability and while they are shown to be closely related to the anomalous atmospheric circulation, they are shown to have no consistent relationship act to precipitation variability. |
