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Hydrological parametrization through remote sensing in the Volta Basin West Africa

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Title Hydrological parametrization through remote sensing in the Volta Basin West Africa
 
Creator Hafeez, M.
Andreini, Marc
Liebe, Jens R.
Friesen, J.
Marx, A.
Giesen, Nick van de
 
Description Ground-based hydrological data collection tends to be difficult and costly, especially in
developing countries such as Ghana and Burkina Faso where the infrastructure for
scientific monitoring is limited. Remote sensing has the potential to fill the gaps in
observation networks. The GLOWA Volta Project (GVP) seeks to maximize the
information to be gained from satellite imagery by combining remotely sensed data with
strategically chosen ground observations. However, there is very limited information
about the coupling of remotely sensed data with ground based data over the mixed
savanna terrain of West Africa. This paper provides an overview of innovative techniques
to measure hydrological parameters as actual evapotranspiration, rainfall, and surface
runoff over mixed savanna terrain in a semi-arid region in West Africa, and their
potential use. Evapotranspiration - The Surface Energy Balance Algorithm for Land
(SEBAL) was used to calculate sensible heat flux and evapotranspiration through the
energy balance. The SEBAL parameterization is an iterative and feedback-based
numerical procedure that deduces the radiation, heat and evaporation fluxes. Along a
1,000 km gradient in the Volta Basin, three scintillometers were installed to measure
sensible heat flux over distances comparable to NOAA-AVHRR pixels, approximately
two kilometers. The comparison of sensible heat flux measured from remotely sensed
data and scintillometers provide accurate results. This will help to increase the reliability
of SEBAL parameterization. Rainfall - Depending on the region within the Volta Basin,
up to 90% of the precipitation in originates from squall-lines. The Tropical Rainfall
Measuring Mission (TRMM) imagery provides a valuable tool to monitor such squall
lines. However, the TRMM signal should be validated for squall line rainfall. To increase
the reliability of space-based rainfall measurements, TRMM based rainfall rate estimates
were calibrated with rainfall measurements from a dense network of rain gauges. Surface
Runoff - Remote sensing has limited value in estimating surface runoff. The savanna of
West Africa, however, is dotted with a large number of small reservoirs used to supply
water for households, cattle, and small scale irrigation. Bathymetry of sixty reservoirs in
Ghana's Upper-East Region produced a very regular correlation between surface area, as
observable by satellites, and volumes. By using all-weather RADAR imagery and the
measured surface/volume curves, surface runoff volumes can be monitored throughout
the year. These indirect runoff measurements will help researchers to develop surfacerunoff
models for the Volta Basin.
 
Date 2007
2012-05-21T06:59:43Z
2012-05-21T06:59:43Z
 
Type Journal Article
 
Identifier Hafeez, M., Andreini, M., Liebe, J., Friesen, J., Marx, A., van de Giesen, N. 2007. Hydrological parametrization through remote sensing in the Volta Basin, West Africa. J. River Basin Man. 5(1)
https://hdl.handle.net/10568/17149
 
Language en
 
Rights Limited Access
 
Source Journal of River Basin Management