Sea surface temperatures around the souhtern [i.e. southern] African coast : climatological aspects and applications

[摘要] ENGLISH ABSTRACT:The oceanic and meteorological systems that characterize the southern African coastline arewell-documented. In this thesis, these characteristics have been considered in conjunction withthe analysis of a unique set of sea surface temperature (SST) data, obtained from measuringsites around the southern African coast, to determine the variability of SSTs in the immediatecoastal region of southern Africa, and to demonstrate how this variability impacts on marinerelatedeconomic activities. As part of the analysis process, various statistical techniques havebeen applied to the data over different time periods to establish the extent of the spatialvariability of SSTs along the southern African coastline.From the results it has been possible to identify three distinctly different 'climatological' regionsaround the southern African coast; viz a cooler west coast region with a low annual andseasonal SST variability and a higher variability from day-ta-day, a warmer east coast regionwith a higher annual and seasonal SST variability and a lower variability from day-ta-day; and atemperate south coast region with a highly erratic annual, seasonal and day-ta-day SSTvariability. Furthermore, it has been possible to identify, albeit small, the existence of a high anda low frequency signal of 12-15 days and 40-60 days, respectively, in the three different regions.There is also evidence of the periodic occurrence of anomalously warm and cold SST events inall three regions, and a probability of <1.1% of a day-ta-day SST anomaly of >3°C (+3°C or-3°C) occurring anywhere along the southern African coastline.The general causes of SST change have been discussed within the context of the heat budgetequation. Furthermore, the effects of the variability of SST on the climate and marine life aroundsouthern Africa and the resulting impact on the various marine-related economic activities (suchas aquaculture, air-sea rescue and power stations) have been identified, and shown to be bothpositive and negative.Finally, it should be noted, that economic infonnation relating to marine activities is closelyguarded due to inter-industry competition. It has therefore been difficult to quantify the exactimpact of the effects of SST variability on these activities.

[发布机构] Stellenbosch University