Application of AVHRR imagery and GRACE measurements for calculation of actual evapotranspiration over the Quaternary aquifer (Lake Chad basin) and validation of groundwater models

The paper presents an application of NOAA-AVHRR and GRACE data for studying the regional hydrogeology of the Quaternary aquifer in the Lake Chad basin. The actual evapotranspiration (ET) over the phreatic aquifer is computed using the S-SEBI algorithm and then compared to the ET estimates derived from the GRACE land water solutions. Both the GRACE solutions and the S-SEBI results are similar in description of the actual ET over the Lake Chad basin. AVHRR data helped to overcome non-uniqueness in the modelling of the piezometry anomalies. Particularly, in regional groundwater models, the Harr piezometric dome appeared to be an area of relatively high effective recharge, while the Chari-Baguirmi and the Kadzell piezometric depressions and Bahr-el-Gahzal were probably areas of excess ET over recharge.

[1]  A. Cazenave,et al.  Recovery of global time-variations of surface water mass by GRACE geoid inversion , 2005 .

[2]  M. Leblanc.  The use of remote sensing and GIS for water resources management of large semi-arid regions : a case study of the Lake Chad Basin, Africa , 2002 .

[3]  Jeffrey P. Walker,et al.  THE GLOBAL LAND DATA ASSIMILATION SYSTEM , 2004 .

[4]  E. Linacre.  Data-sparse estimation of lake evaporation, using a simplified Penman equation , 1993 .

[5]  P. Döll,et al.  A global hydrological model for deriving water availability indicators: model tuning and validation , 2003 .

[6]  George Ohring,et al.  On the Relationship between Clear-Sky Planetary and Surfae Albedos , 1984 .

[7]  Michael T. Coe,et al.  Human and natural impacts on the water resources of the Lake Chad basin , 2001 .

[8]  Christopher B. Jones,et al.  Application of Meteosat thermal data to map soil infiltrability in the central part of the Lake Chad basin, Africa. , 2003 .

[9]  I. C. Prentice,et al.  A dynamic global vegetation model for studies of the coupled atmosphere‐biosphere system , 2005 .

[10]  A. Cazenave,et al.  Time-variations of the regional evapotranspiration rate from GRACE satellite gravimetry , 2006 .

[11]  J. Wallace,et al.  Soil evaporation from tiger-bush in south-west Niger , 1997 .

[12]  V. Caselles,et al.  A split‐window algorithm for land surface temperature from advanced very high resolution radiometer data: Validation and algorithm comparison , 1997 .

[13]  M. Watkins,et al.  The gravity recovery and climate experiment: Mission overview and early results , 2004 .

[14]  M. S. Moran,et al.  Assessing the Spatial Distribution of Evapotranspiration Using Remotely Sensed Inputs , 1991 .

[15]  Massimo Menenti,et al.  S-SEBI: A simple remote sensing algorithm to estimate the surface energy balance , 2000 .

[16]  P. Milly,et al.  Global Modeling of Land Water and Energy Balances. Part I: The Land Dynamics (LaD) Model , 2002 .

[17]  Frédéric Frappart,et al.  Time variations of land water storage from an inversion of 2 years of GRACE geoids , 2005 .

[18]  F. Bryan,et al.  Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE , 1998 .

[19]  J. Monteith.  Weather and water in the Sudano-Sahelian Zone , 1991 .

[20]  M. Castro,et al.  Sensitivity of the Continental Hydrological Cycle to the Spatial Resolution over the Iberian Peninsula , 2004 .

[21]  U. Kafri,et al.  Geochemistry of groundwaters in the Chad basin , 1975 .

[22]  J. Olivry,et al.  Hydrologie du lac Tchad , 1996 .

[23]  G. Favreau,et al.  Data scarcity in the large semiarid Lake Chad basin : incorporating environmental tracers as a priori information for groundwater modelling , 2005 .

[24]  U. Schneider,et al.  Terrestrial Precipitation Analysis: Operational Method and Required Density of Point Measurements , 1994 .

[25]  G. Salvucci.  Soil and moisture independent estimation of stage‐two evaporation from potential evaporation and albedo or surface temperature , 1997 .

[26]  A. Cazenave,et al.  Time variations of the regional evapotranspiration rate from Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry , 2006 .