Premium
Estimation of surface roughness (z 0 ) over a stabilizing coastal dune field based on vegetation and topography
Author(s) -
Levin Noam,
BenDor Eyal,
Kidron Giora J.,
Yaakov Yaron
Publication year - 2008
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/esp.1621
Subject(s) - wind speed , vegetation (pathology) , roughness length , arid , geology , aeolian processes , digital elevation model , environmental science , hydrology (agriculture) , surface roughness , sand dune stabilization , differential gps , physical geography , remote sensing , global positioning system , geomorphology , wind profile power law , geography , oceanography , paleontology , physics , geotechnical engineering , pathology , quantum mechanics , telecommunications , computer science , medicine
Accurate knowledge of the surface roughness and the resultant wind speed are important for many applications, such as climatic models, wind power meteorology, agriculture and erosion hazards, especially on sand dunes in arid and semi‐arid environments, where vegetation cover is scarce. In this study we aimed at quantifying the effects of vegetation cover and topography on surface roughness over a stabilizing dune field on the southern coast of Israel. Forty‐six wind measurements were made at various distances from the coastline, ranging from 10 to 2800 m, and z 0 values were calculated from the wind measurements based on the ratio between the wind gust and the average wind speed. We estimated vegetation cover using the soil adjusted vegetation index (SAVI) from Landsat satellite images for the upwind sector at various lengths, ranging from 15 to 400 m, and based on digital elevation models and differential GPS field measurements we calculated the topographic variable of the relative heights of the stations. z 0 values were positively correlated with the winter SAVI values ( r = 0·87 at an upwind length of 200 m) and negatively correlated with the relative height ( r = −0·68 at an upwind length of 200–400 m for the inland dune stations). Using these variables we were able to create a map of estimated z 0 values having an accuracy of over 64%. Such maps provide a better understanding of the spatial variability in both wind speed and sand movement over coastal dune areas. Copyright © 2007 John Wiley & Sons, Ltd.