Title: Quantifying migration rates of barchan dunes using radar and optical remote sensing imagery
Authors: Mohamed, Ihab
Delgado Blasco, Manu
Hanssen, Ramon
Verstraeten, Gert
Issue Date: Jun-2014
Publisher: University of Warsaw
Host Document: 34th EARSeL Symposium European remote sensing - new opportunities for science and practice. Abstract and Programme Book pages:57
Conference: EARSeL Symposium edition:34 location:Warsaw date:16-20 June 2014
Abstract: Quantifying sand dune migration is an important aspect in analyzing desert dunes and in particular barchans
dunes. Moreover, identifying the active barchans and estimating their migration rate are crucial steps for
proper understanding and assessment of sand encroachment hazard. The increasing availability of remote
sensing data for larger regions have made it possible to study (less)inaccessible regions such as large
desert dune fields. Contrary to the detailed study on individual dunes, this has also made it possible to study
the dynamics of entire dune fields. Multi-temporal analysis of remote sensing data offers to the potential to
quantify dune migrations rates and sand fluxes. However, the reflectance properties of dune surfaces
challenges the automatic detection and delineation of sand dunes, and thus also the automatic calculation of
migration rates. In this study, barchan dunes in the South-Rayan dunefield (SRFD) in central Egypt were
therefore examined through a combination of optical RS data(i.e. multi-temporal Landsat imagery) as well as
with active RS data (i.e. Envisat ASAR SLC images). The method used for extracting dunes’ shape from
radar imagery is easier, faster and requires minimum human interaction than their extraction from optical
data, however, the latter are more readily available and require less preprocessing. The dune migration rate
in m a-1 of 43 dunes was estimated based on the calculation of the movement of centroids (i.e. centroid
displacement) corresponding to each dune. Fieldwork (i.e. GPS-surveyed dune boundaries) and a recent
GeoEye image were integrated to assess the results. Results obtained with optical and radar imagery are
similar and point towards an average migration rate of 4.4 m a-1, with values for individual dunes ranging
from 1 m a-1 to 18 m a-1. Moreover, the dune migration was found to be mainly controlled by dune size and
the interdune slope-aspect. The centroid displacement technique is a successful approach that enabled a
fully automatic calculation of barchans dune migration. This abstracts fits within the APLADYN project: a
Belgian Science Policy projection anthropogenic and landscape dynamics in large fluvial systems.
ISBN: 978-83-63245-57-3
Publication status: published
KU Leuven publication type: IMa
Appears in Collections:Division of Geography & Tourism

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