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WIND ENERGY VARIATIONS IN THE SOUTHWESTERN KALAHARI DESERT AND IMPLICATIONS FOR LINEAR DUNEFIELD ACTIVITY
Author(s) -
BULLARD J. E.,
THOMAS D. S. G.,
LIVINGSTONE I.,
WIGGS G. F. S.
Publication year - 1996
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/(sici)1096-9837(199603)21:3<263::aid-esp627>3.0.co;2-i
Subject(s) - aeolian processes , vegetation (pathology) , geology , vegetation cover , physical geography , wind direction , sand dune stabilization , prevailing winds , period (music) , desert (philosophy) , wind speed , climatology , geomorphology , geography , ecology , oceanography , philosophy , epistemology , medicine , physics , pathology , biology , acoustics , grazing
The southwestern Kalahari linear dunefield, which displays marked morphological variability, possesses a partial but temporally and spatially variable vegetation cover and has frequently been described as a palaeodunefield. Palaeo status has been ascribed on the basis of several criteria including the presence of vegetation, but also because dunes are thought to be out of alignment with modern resultant potential sand‐moving wind directions and because present‐day wind energy is regarded as low. For the period 1960–1992, wind data from eight dunefield meteorological stations are analysed in detail to examine these assertions. Potential sand transport directions, including spatial and temporal variations, and potential drift directions for the windiest three month periods, are calculated and explained. It is concluded that the present‐day potential sand transport environment is markedly variable from year to year and from place to place. While periods of low sand transport energy do occur, it is also noted that the 1980s possessed considerable potential for sand transport in the dunefield. Directional variability is also relatively high, perhaps exceeding that under which linear dunes can be expected to form. Because linear dune aeolian activity has a number of states, however, the present‐day wind environment may allow dune surface aeolian activity to occur which does not alter the overall pattern of the dunes.