Abstract's details
long series of Altimetry and Discharge in the Congo Basin
CoAuthors
Event: 2016 Ocean Surface Topography Science Team Meeting
Session: Science III: Two decades of continental water's survey from satellite altimetry - From nadir low-resolution mode to SAR altimetry, new perspectives for hydrology
Presentation type: Type Poster
Contribution: not provided
Abstract:
The Congo is the second largest hydrological basin the world, and also one of the less monitored. We present the largest ever built database of water stages in the bassin by processing the ENVISAT, SARAL and Jason-2 missions, reaching a total of 350+ Virtual Stations. Reprocessing of former missions such as T/P and ERS-2 have been released recently and we also present preliminary series that enable tracking the water level variations back to the mid 90'.
We have tuned the MGB rain-discharge model developped by IPH for the Congo Basin and estimated discharge at each Virtual Station. Because of the lack of in-situ discharge data that is required to tune the model, results are unequal throughout the Basin. Last, we computed the rating curves that relate discharge to water level. Quality indicators such as the NS coeficient between model and RC-derived discarges show that a good agreemnt (NS>0.7) is found in the Northen part where the Bangui series could be used to tune the model but worse results are obtained for the left bank contributors such as the Kasai sub-basin. We discuss the possible causes of these bad agreements, including erroneous rain fields and model limitation such as impact of the Lakes and wetlands.
We take the opportunity of this case study to show how altimetry can be used to assess the quality of discharge series through the quality of fit found in the détermination of hundreds of rating Curve coefficients.
We have tuned the MGB rain-discharge model developped by IPH for the Congo Basin and estimated discharge at each Virtual Station. Because of the lack of in-situ discharge data that is required to tune the model, results are unequal throughout the Basin. Last, we computed the rating curves that relate discharge to water level. Quality indicators such as the NS coeficient between model and RC-derived discarges show that a good agreemnt (NS>0.7) is found in the Northen part where the Bangui series could be used to tune the model but worse results are obtained for the left bank contributors such as the Kasai sub-basin. We discuss the possible causes of these bad agreements, including erroneous rain fields and model limitation such as impact of the Lakes and wetlands.
We take the opportunity of this case study to show how altimetry can be used to assess the quality of discharge series through the quality of fit found in the détermination of hundreds of rating Curve coefficients.