The ENSO Signal in Botswanan Rainfall and Anticipated Impacts of the Current ENSO Event

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Abstract ATM-9805178 Nicholson, Sharon E. Florida State University Title: The ENSO Signal in Botswanan Rainfall and Anticipated Impacts of the Current ENSO Event ENSO events are usually associated with drought in much of Southern Africa. One of the areas most strongly affected is Botswana where rainfall was 40 to 80% below normal during the 1991/92 ENSO episode. Preliminary work shows that the association between ENSO and rainfall in Southern Africa is more complex than the simple occurrence of drought. Although droughts commonly occur during ENSO episodes, early in many episodes there is actually an increase of rainfall in some regions and not all ENSO events are associated with droughts. This SGER award supports research to better understand the sequence of rainfall response within the current ENSO episode and the conditions under which a given ENSO event evokes a precipitation signal over Southern Africa. The sequential development of ENSO episodes also appears to have changed since the late 1970's, when a general warming occurred in the world's oceans and the current ENSO appears to be taking a somewhat different course than other intense events. The on-going ENSO event will be used to address the nature of these events and the character of the paleoclimate signal evoked.