Assessment of Digital Elevation Model (DEM) aggregation methods for hydrological modeling: Lake Chad basin, Africa

Coz, Mathieu Le; Dagognet, François; Genthon, Pierre; Favreau, Guillaume

doi:10.1016/j.cageo.2008.07.009

Cited by 48 publications

(24 citation statements)

References 21 publications

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“…In this region elevation ranges from 300 m above sea level around Kousseri to about 1200 m above sea level in the Adamawa Plateau. Apart from some local mountains in the south the basin topography is quite flat with an average slope of about 1.3% in a south to north gradient (Le Coz et al ., ) (see Figure ).…”

Section: Methodsmentioning

confidence: 95%

Evaluating global reanalysis precipitation datasets with rain gauge measurements in the Sudano‐Sahel region: case study of the Logone catchment, Lake Chad Basin

Nkiaka

Nawaz

Lovett

2016

Meteorological Applications

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Africa has a paucity of long term reliable meteorological ground station data and reanalysis products are used to provide the climate estimations that are important for climate change projections. In this paper monthly observed precipitation records in the Logone catchment of the Lake Chad Basin are used to evaluate the performance of two global reanalysis products: the Climate Forecasting System Reanalysis (CFSR) and ERA Interim datasets. The two reanalysis products reproduced the monthly, annual and decadal cycle of precipitation and variability relatively accurately albeit with some discrepancies. The catchment rainfall gradient was also well captured by the two products. There are good correlations between the reanalysis and rain gauge datasets although significant deviations exist, especially for CFSR. Both reanalysis products overestimated rainfall in 68% of the rain gauge stations. ERA Interim produced the lowest bias and mean absolute error with average values of 2% and 6.5 mm month −1 respectively compared to 15% and 34 mm month −1 for the CFSR. However, both reanalysis products systematically underestimated annual rainfall in the catchment during the period 1997-2002 for ERA Interim and 1998-2000 for CFSR. This research demonstrates that evaluating reanalysis products in remote areas like the Logone catchment enables users to identify artefacts inherent in reanalysis datasets. This will facilitate improvements in certain aspects of the reanalysis forecast model physics and parameterization to improve reanalysis dataset quality. This study concludes that the application of each reanalysis product in the catchment will depend on the purpose for which it is to be used and the spatial scale required.

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Section: Methodsmentioning

confidence: 95%

Evaluating global reanalysis precipitation datasets with rain gauge measurements in the Sudano‐Sahel region: case study of the Logone catchment, Lake Chad Basin

Nkiaka

Nawaz

Lovett

2016

Meteorological Applications

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“…Previous studies have applied remote sensing and satellite data to the Lake Chad region-some of which focused on the changes in stream flow patterns connected to the lake [9,[13][14][15], Leblanc et al [16] reported on the existence of a mega-lake Chad. They used satellite images from Landsat and Moderate Resolution Imaging Spectrometer (MODIS) for their studies.…”

Section: Parametermentioning

confidence: 99%

Hydrological Evaluation of Lake Chad Basin Using Space Borne and Hydrological Model Observations

Buma

Seo

2016

Water

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Sustainable water resource management requires the assessment of hydrological changes in response to climate fluctuations and anthropogenic activities in any given area. A quantitative estimation of water balance entities is important to understand the variations within a basin. Water resources in remote areas with little infrastructure and technological knowhow suffer from poor documentation, rendering water management difficult and unreliable. This study analyzes the changes in the hydrological behavior of the Lake Chad basin with extreme climatic and environmental conditions that hinder the collection of field observations. Total water storage (TWS) from the Gravity Recovery and Climate Experiment (GRACE), lake level variations from satellite altimetry, and water fluxes and soil moisture from Global Land Data Assimilation System (GLDAS) were used to study the spatiotemporal variability of the hydrological parameters of the Lake Chad basin. The estimated TWS varies in a similar pattern as the lake water level. TWS in the basin area is governed by the lake's surface water. The subsurface water volume changes were derived by combining the altimetric lake volume with the TWS over the drainage basin. The results were compared with groundwater outputs from WaterGAP Global Hydrology Model (WGHM), with both showing a somewhat similar pattern. These results could provide an insight to the availability of water resources in the Lake Chad basin for current and future management purposes.

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“…The SRTM was preprocessed as follows. First, we re-gridded it to a coarser cell-size by averaging the elevation values as suggested by Le Coz et al (2009) in a study targeting the area around the Lake Chad. Second, we applied a hole-filling method to the re-gridded version of the SRTM in order to filter out remnant troughs, and ensure that no depressions exist.…”

Section: Table 1 Around Herementioning

confidence: 99%

Testing the skill of numerical hydraulic modeling to simulate spatiotemporal flooding patterns in the Logone floodplain, Cameroon

Fernández

Najafi

Durand

et al. 2016

Journal of Hydrology

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Recent innovations in hydraulic modeling have enabled global simulation of rivers, includingsimulation of their coupled wetlands and floodplains. Accurate simulations of floodplains using these approaches may imply tremendous advances in global hydrologic studies and in biogeochemical cycling. One such innovation is to explicitly treat sub-grid channels within twodimensional models, given only remotely sensed data in areas with limited data availability.However, predicting inundated area in floodplains using a sub-grid model has not been rigorously validated. In this study, we apply the LISFLOOD-FP hydraulic model using a subgrid channel parameterization to simulate inundation dynamics on the Logone River floodplain, in northern Cameroon, from 2001 to 2007. Our goal was to determine whether floodplain dynamics could be simulated with sufficient accuracy to understand human and natural contributions to current and future inundation patterns. Model inputs in this data-sparse region include in situ river discharge, satellite-derived rainfall, and the shuttle radar topography mission (SRTM) floodplain elevation. We found that the model accurately simulated total floodplain inundation, with a Pearson correlation coefficient greater than 0.9, and RMSE less than 700 km 2 , compared to peak inundation greater than 6,000 km 2 . Predicted discharge downstream of the floodplain matched measurements (Nash-Sutcliffe efficiency of 0.81), and indicated that net flow from the channel to the floodplain was modeled accurately. However, the spatial pattern of inundation was not well simulated, apparently due to uncertainties in SRTM elevations. We evaluated model results at 250, 500 and 1000-m spatial resolutions, and found that results are insensitive to spatial resolution. We also compared the model output against results from run of LISFLOOD-FP in which the sub-grid channel parameterization was disabled, finding that the 6 sub-grid parameterization simulated more realistic dynamics. These results suggest that analysis of global inundation is feasible using a sub-grid model, but that spatial patterns at sub-kilometer resolutions still needs to be adequately predicted. Highlights*Sub-grid channel modeling in hydraulic simulations has not been fully validated in floodplains *We apply the LISFLOOD-FP model to simulate inundation dynamics on the Logone floodplain *Total inundation and flow into the floodplain are accurately simulated, but no spatial patterns *Mismatch in spatial patterns is likely due to uncertainties in the digital elevation model *Results suggest that analysis of global inundation is feasible using a sub-grid model

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Assessment of Digital Elevation Model (DEM) aggregation methods for hydrological modeling: Lake Chad basin, Africa

Cited by 48 publications

References 21 publications

Evaluating global reanalysis precipitation datasets with rain gauge measurements in the Sudano‐Sahel region: case study of the Logone catchment, Lake Chad Basin

Evaluating global reanalysis precipitation datasets with rain gauge measurements in the Sudano‐Sahel region: case study of the Logone catchment, Lake Chad Basin

Hydrological Evaluation of Lake Chad Basin Using Space Borne and Hydrological Model Observations

Testing the skill of numerical hydraulic modeling to simulate spatiotemporal flooding patterns in the Logone floodplain, Cameroon

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