A morphometric comparison of the Namib and southwest Kalahari dunefields using ASTER GDEM data

Kevin White, Joanna Bullard, Ian Livingstone, Lisa Moran

    Research output: Contribution to JournalArticle

    Abstract

    The increased availability of digital elevation models and satellite image data enable testing of morphometric relationships between sand dune variables (dune height, spacing and equivalent sand thickness), which were originally established using limited field survey data. These long-established geomorphological hypotheses can now be tested against very much larger samples than were possible when available data were limited to what could be collected by field surveys alone. This project uses ASTER global digital elevation model (GDEM) data to compare morphometric relationships between sand dune variables in the southwest Kalahari dunefield to those of the Namib sand sea, to test whether the relationships found in an active sand sea (Namib) also hold for the fixed dune system of the nearby southwest Kalahari. The data show significant morphometric differences between the simple linear dunes of the Namib sand sea and the southwest Kalahari; the latter do not show the expected positive relationship between dune height and spacing. The southwest Kalahari dunes show a similar range of dune spacings, but they are less tall, on average, than the Namib sand sea dunes. There is a clear spatial pattern to these morphometric data; the tallest and most closely spaced dunes are towards the southeast of the Kalahari dunefield; and this is where the highest values of equivalent sand thickness result. We consider the possible reasons for the observed differences and highlight the need for more studies comparing sand seas and dunefields from different environmental settings.
    Original languageEnglish
    Pages (from-to)87-95
    Number of pages9
    JournalAeolian Research
    Volume19
    DOIs
    Publication statusPublished - 26 Oct 2015

    Fingerprint

    ASTER
    digital elevation model
    dune
    sand
    spacing
    field survey
    comparison
    sea

    Keywords

    • Aeolian processes
    • Kalahari
    • Linear dunes
    • Morphometric analysis
    • Namib sand sea

    Cite this

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    abstract = "The increased availability of digital elevation models and satellite image data enable testing of morphometric relationships between sand dune variables (dune height, spacing and equivalent sand thickness), which were originally established using limited field survey data. These long-established geomorphological hypotheses can now be tested against very much larger samples than were possible when available data were limited to what could be collected by field surveys alone. This project uses ASTER global digital elevation model (GDEM) data to compare morphometric relationships between sand dune variables in the southwest Kalahari dunefield to those of the Namib sand sea, to test whether the relationships found in an active sand sea (Namib) also hold for the fixed dune system of the nearby southwest Kalahari. The data show significant morphometric differences between the simple linear dunes of the Namib sand sea and the southwest Kalahari; the latter do not show the expected positive relationship between dune height and spacing. The southwest Kalahari dunes show a similar range of dune spacings, but they are less tall, on average, than the Namib sand sea dunes. There is a clear spatial pattern to these morphometric data; the tallest and most closely spaced dunes are towards the southeast of the Kalahari dunefield; and this is where the highest values of equivalent sand thickness result. We consider the possible reasons for the observed differences and highlight the need for more studies comparing sand seas and dunefields from different environmental settings.",
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    A morphometric comparison of the Namib and southwest Kalahari dunefields using ASTER GDEM data. / White, Kevin; Bullard, Joanna; Livingstone, Ian; Moran, Lisa.

    In: Aeolian Research, Vol. 19, 26.10.2015, p. 87-95.

    Research output: Contribution to JournalArticle

    TY - JOUR

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    AU - White, Kevin

    AU - Bullard, Joanna

    AU - Livingstone, Ian

    AU - Moran, Lisa

    PY - 2015/10/26

    Y1 - 2015/10/26

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    AB - The increased availability of digital elevation models and satellite image data enable testing of morphometric relationships between sand dune variables (dune height, spacing and equivalent sand thickness), which were originally established using limited field survey data. These long-established geomorphological hypotheses can now be tested against very much larger samples than were possible when available data were limited to what could be collected by field surveys alone. This project uses ASTER global digital elevation model (GDEM) data to compare morphometric relationships between sand dune variables in the southwest Kalahari dunefield to those of the Namib sand sea, to test whether the relationships found in an active sand sea (Namib) also hold for the fixed dune system of the nearby southwest Kalahari. The data show significant morphometric differences between the simple linear dunes of the Namib sand sea and the southwest Kalahari; the latter do not show the expected positive relationship between dune height and spacing. The southwest Kalahari dunes show a similar range of dune spacings, but they are less tall, on average, than the Namib sand sea dunes. There is a clear spatial pattern to these morphometric data; the tallest and most closely spaced dunes are towards the southeast of the Kalahari dunefield; and this is where the highest values of equivalent sand thickness result. We consider the possible reasons for the observed differences and highlight the need for more studies comparing sand seas and dunefields from different environmental settings.

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    KW - Kalahari

    KW - Linear dunes

    KW - Morphometric analysis

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    UR - http://www.mendeley.com/research/morphometric-comparison-namib-southwest-kalahari-dunefields-using-aster-gdem-data

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