Name
Title | ||
|---|---|---|
Assessment of Digital Elevation Model (DEM) aggregation methods for hydrological modeling: Lake Chad basin, Africa |
Abstract | ||
|---|---|---|
Digital Elevation Models (DEMs) are used to compute the hydro-geomorphological variables required by distributed hydrological models. However, the resolution of the most precise DEMs is too fine to run these models over regional watersheds. DEMs therefore need to be aggregated to coarser resolutions, affecting both the representation of the land surface and the hydrological simulations. In the present paper, six algorithms (mean, median, mode, nearest neighbour, maximum and minimum) are used to aggregate the Shuttle Radar Topography Mission (SRTM) DEM from 3'' (90m) to 5' (10km) in order to simulate the water balance of the Lake Chad basin (2.5Mkm^2). Each of these methods is assessed with respect to selected hydro-geomorphological properties that influence Terrestrial Hydrology Model with Biogeochemistry (THMB) simulations, namely the drainage network, the Lake Chad bottom topography and the floodplain extent. The results show that mean and median methods produce a smoother representation of the topography. This smoothing involves the removing of the depressions governing the floodplain dynamics (floodplain area14,000km^2 with the maximum or nearest neighbour) but results in anomalies concerning the drainage network. An aggregation procedure based on a variographic analysis of the SRTM data is therefore suggested. This consists of preliminary filtering of the 3'' DEM in order to smooth spikes and wells, then resampling to 5' via the nearest neighbour method so as to preserve the representation of depressions. With the resulting DEM, the drainage network, the Lake Chad bathymetric curves and the simulated floodplain hydrology are consistent with the observations (3% underestimation for simulated evaporation volumes). |
Year | DOI | Venue |
|---|---|---|
2009 | 10.1016/j.cageo.2008.07.009 | Computers & Geosciences |
Keywords | Field | DocType |
floodplain extent,nearest neighbour,aggregation method,digital elevation model,lake chad bottom topography,hydrological modeling,simulated floodplain hydrology,floodplain area14,nearest neighbour method,lake chad bathymetric curve,lake chad basin,floodplain dynamic,drainage network,srtm,wells,floodplains,evaporation,radar,topography,drainage,properties,analysis,shuttle radar topography mission,aggregation,algorithms,water balance,biogeochemistry,simulation,hydrology,assessment | Water balance,Drainage basin,Computer science,Hydrology,Drainage system (geomorphology),Drainage divide,Shuttle Radar Topography Mission,Bathymetry,Digital elevation model,Structural basin | Journal |
Volume | Issue | ISSN |
35 | 8 | Computers and Geosciences |
Citations | PageRank | References |
3 | 0.68 | 2 |
Authors | ||
4 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Mathieu Le Coz | 1 | 21 | 2.13 |
| François Delclaux | 2 | 3 | 1.02 |
| Pierre Genthon | 3 | 3 | 0.68 |
| Guillaume Favreau | 4 | 3 | 0.68 |