Improvement of river network representation in Africa: application of an approach based on digital elevation data and environmental characteristics
<p>In many continental databases representing rivers across Africa, information on rivers characteristics (length, width, intermittent or perennial) is often incomplete, and small streams are largely underrepresented. Fortunately, the use of topographic information from digital elevation model...
Guardado en:
| Autores principales: | , , |
|---|---|
| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
|
| Materias: | |
| Acceso en línea: | https://doaj.org/article/cc7f9969bb2c486e9194193d000b20fc |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| Sumario: | <p>In many continental databases representing rivers across Africa, information on rivers characteristics (length, width, intermittent or perennial) is often incomplete, and small streams are largely underrepresented. Fortunately, the use of topographic information from digital elevation models (DEMs) provides an opportunity to have more
detailed information on rivers, particularly small streams in broad areas. A common approach to extract streams from DEM is to consider as a stream all DEM cells that drain at least a certain upstream surface, commonly known as the minimum contributing area (<span class="inline-formula"><i>A</i><sub>min</sub></span>). This parameter (<span class="inline-formula"><i>A</i><sub>min</sub></span>) is generally defined uniformly over large areas and this independently of the very variable climate and landscape conditions so that the generated streams have a rather uniform spatial distribution. To address this issue, using a 3<span class="inline-formula"><sup>′′</sup></span> (approx. 90 m <span class="inline-formula">×</span> 90 m) DEM of Burkina Faso, the relationship between <span class="inline-formula"><i>A</i><sub>min</sub></span> and the observed drainage density (Dd<span class="inline-formula"><sub>obs</sub></span>) was established with satisfactory performance (<span class="inline-formula"><i>r</i><sup>2</sup>=0.86</span>). In ongoing work, the functional relationship between the observed drainage densities (Dd<span class="inline-formula"><sub>obs</sub></span>) and environmental variables (lithology, climate, geology, vegetation cover) should allow for the establishment of the relationships between <span class="inline-formula"><i>A</i><sub>min</sub></span> and the environmental variables. This relationship allows for spatially variable <span class="inline-formula"><i>A</i><sub>min</sub></span> values depending on landscape characteristics. Before
extracting river networks in Africa, the next step will be to validate or
update these relationships in several countries.</p> |
|---|