تقييم دقة استخدام نماذج ارتفاعية رقمية لتحديد بعض خصائص حوضي صدد و الأبرش في سورية

الملخص EN

Digital Elevation Models (DEMs) are used for a wide range of hydrological, geomorphological, environmental applications, etc.

As long DEM offer almoS global coverage and available for users free of charge in moS cases.

In this study, four different DEMs :SRTM 30m, AW3D 30m, ASTERGDEM30m and HydroSHED 90m , were evaluated in two different watersheds in Syria: Sadad basin, where the topography was approximately flat, and Al-Abrash basin, which has very diverse terrain landscape (flat, hills and mountain).

Extracted elevation, Drainage locations, and watersheds from different DEMs were compared with the ones derived from1/ 50000 topographic map.

The statistical analysis showed that the Root Mean Squared Error (RMSE) value of the derived elevations are 5.7, 6, 8.5, 12m for the DEMs: SRTM 30m, AW3D 30m, ASTERGDEM 30m and HydroSHED 90m respectively for Sadad basin.

and 12.1, 12.3, 13.7, 20.3 m for DEMs :AW3D 30m, SRTM 30m, ASTERGDEM 30m, HydroSHED 90m, respectively for Abrash basin.

The spatial agreement of the derived Sreams from the different DEMs compared to the topographic map of the study area showed that the ones extracted from AW3D 30m has the higheS spatial agreement in the both study areas followed by the ones derived from SRTM 30m.

When comparing the areas of watersheds, the relative error ranges between 2.6% for SRTM30m and 33% for the ASTERGDEM30m model in Sadad basin.

while in Abrash Basin, this error ranges from 2.4% for SRTM 30m to 8.9 % for ASTERGDEM30m .

The spatial agreement comparison showed that the delineated basin from AW3D 30m was the most compatible in Sadad basin , while the one resulted from SRTM 30m was the most compatible in the Abrash basin.

In general, the superiority of AW3D 30m and SRTM 30m mdels over the other two DEMs was found to be consiSent even under different study areas, in terms of extracting elevation, streams, and watersheds.