caa a22 4500 605474737 CHVBK 20210128100348.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00382-014-2230-5 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2230-5 A synoptic decomposition of rainfall over the Cape south coast of South Africa [Elektronische Daten] [Christien Engelbrecht, Willem Landman, Francois Engelbrecht, Johan Malherbe] A synoptic climatology is derived for the Cape south coast region of South Africa by application of the self-organizing map (SOM) technique. The SOM is applied to average daily low-level circulation fields, as represented by sea-level pressure anomalies for the period 1979-2011. This coastal region receives rainfall all-year round with slight peaks during March-April and with more pronounced peaks during August and October-November. The synoptic forcing responsible for this annual multi-modal rainfall distribution is identified, and the relative contribution of different synoptic types to the annual rainfall is quantified. Ridging high pressure systems contribute to 46% of the annual rainfall, while tropical-temperate troughs contribute 28%. Cut-off lows (COLs) co-occurring with ridging highs and tropical-temperate troughs are associated with 16% of the annual rainfall total. The contribution of ridging high pressure systems decreases from south to north, whilst the opposite is true for tropical-temperate troughs. COLs, ridging high pressure systems and tropical-temperate troughs are associated with the March-April rainfall peak, while COLs are largely associated with the August rainfall peak. Ridging high pressure systems and to a lesser extent tropical-temperate troughs, are responsible for the October peak observed along the coast, while the November peak over the adjacent interior regions is associated with COLs that occur in combination with the tropical-temperate troughs during this month. Springer-Verlag Berlin Heidelberg, 2014 All-year rainfall region nationallicence Cape south coast of South Africa nationallicence Synoptic types nationallicence Cut-off lows nationallicence Ridging high pressure systems nationallicence Engelbrecht Christien Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa aut Landman Willem Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa aut Engelbrecht Francois Climate Studies, Modelling and Environmental Health, CSIR Natural Resources and Environment, Pretoria, South Africa aut Malherbe Johan Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa aut Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2589-2607 0930-7575 44:9-10<2589 2015 44 382 https://doi.org/10.1007/s00382-014-2230-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2230-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Engelbrecht Christien Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa aut NATIONALLICENCE 700 1- Landman Willem Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa aut NATIONALLICENCE 700 1- Engelbrecht Francois Climate Studies, Modelling and Environmental Health, CSIR Natural Resources and Environment, Pretoria, South Africa aut NATIONALLICENCE 700 1- Malherbe Johan Institute for Soil, Climate and Water, Agricultural Research Council, Pretoria, South Africa aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2589-2607 0930-7575 44:9-10<2589 2015 44 382