Title of article :
Late Quaternary dynamics of southern Africaʹs winter rainfall zone
Author/Authors :
Chase، نويسنده , , Brian M. and Meadows، نويسنده , , Michael E.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Pages :
36
From page :
103
To page :
138
Abstract :
Variations in the nature and extent of southern Africaʹs winter rainfall zone (WRZ) have the potential to provide important information concerning the nature of long-term climate change at both regional and hemispheric scales. Positioned at the interface between tropical and temperate systems, southern Africaʹs climate is influenced by shifts in the Intertropical Convergence Zone, the westerlies, and the development and position of continental and oceanic anticyclones. Over the last glacial–interglacial cycle substantial changes in the amount and seasonality of precipitation across the subcontinent have been linked to the relative dominance of these systems. Central to this discussion has been the extent to which the regionʹs glacial climates would have been affected by expansions of Antarctic sea-ice, equatorward migrations of the westerlies, more frequent/intense winter storms and an expanded WRZ. aper reviews the developing body of evidence pertaining to shifts in the WRZ, and the evolution of ideas that have been presented to explain the patterns observed. Dividing the region into three separate axes, along the western and southern margins of the continent and across the interior into the Karoo and the Kalahari, a range of evidence from both terrestrial sites and marine cores is considered, and potential expansions of the WRZ expansions are explored. Despite the limitations of many of the regionʹs proxy records, a coherent pattern has begun to develop of a significantly expanded WRZ during phases of the last glacial period, with the best-documented being between 32–17 ka. While more detailed inferences will require the recovery and analysis of longer and better-dated records, this synthesis provides a new baseline for further research in this key region.
Keywords :
Southern Africa , winter rainfall zone , Palaeoenvironment , Westerlies , Last Glacial Maximum , Quaternary
Journal title :
EARTH-SCIENCE REVIEWS
Serial Year :
2007
Journal title :
EARTH-SCIENCE REVIEWS
Record number :
2334048
Link To Document :
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