Desert, European Centre for Medium-Range Weather Forecasts (ECMWF), European RemoteSensing Satellite Scatterometer (ESCAT), NASA Scatterometer (NSCAT), SeaWinds Scatterometer, dunes, ergs, winds


Radar backscatter (σ˚) from ergs is modulated with view direction [incidence (θ) and azimuth (φ) angles], where the modulation characteristics reflect the surface geometry. σ˚ also varies spatially and reflects the spatial inhomogeneity of the sand surface. We use σ˚ measurements at different θ and φ angles from the NASA, European Remote Sensing satellite, and SeaWinds scatterometers to understand the relationship between wind and erg bedforms. A model incorporating the σ˚ φ-modulation and spatial inhomogeneity is proposed. Surface slope variations are related to the σ˚ spatial inhomogeneity. We compare the backscatter model results with numerically predicted wind direction data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) over the erg surfaces. We use the maxima of the φ-modulation at θ=33˚ to infer the orientation of the dominant slip-sides on the sand surface. These orientations are consistent with the ECMWF wind directions spatially and temporally.

Original Publication Citation

Stephen, H., and D. G. Long. "Spatial and Temporal Behavior of Microwave Backscatter Directional Modulation Over the Saharan Ergs." Geoscience and Remote Sensing, IEEE Transactions on 45.5 (27): 1164-73

Document Type

Peer-Reviewed Article

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Ira A. Fulton College of Engineering and Technology


Electrical and Computer Engineering