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Sudan Journal of Agricultural Research
Estimating actual evapotranspiration using surface energy balance
algorithm for land (SEBAL) for Gezira scheme. Part II: Application and
validation
Bashir M.A., T. Hata, A. Tada , H. Tanakamaru, and Abdelhadi A. W.
Abstract:
Accurate estimation of actual evapotranspiration is very essential for
irrigation performance and water management. This will become more
important and urgent for the Gezira scheme due to frequent shortage and
fluctuation of rainfall. Remote sensing is proving to be a useful tool
for investigating the variations of actual depletion of water for large
irrigated areas such as Gezira scheme. Surface Energy Balance Algorithm
for Land (SEBAL) was applied in this research to estimate the daily
evapotranspiration using different images acquired from Landsat7
Enhanced Thematic Mapper Plus (ETM+). This study aims to estimate the
actual daily evapotranspiration from the Gezira irrigated scheme.
Instantaneous ETa for the Gezira irrigated scheme was computed during
the satellite over flight and integrated for the 24-hours on
pixel-by-pixel basis (30m x 30m). SEBAL results were compared with the
evapotranspiration measured at the Gezira Research Station Farm (GRSF),
during the 2001/02 and 2002/03 seasons using soil moisture depletion
method via regular gravimetric sampling. The results from SEBAL for both
years (2001 and 2002) showed evapotranspiration rate in the range of 1.7
- 4.7 mm/day for the sorghum plots in the GRSF and coincided very well
with the observed values. Daily evapotranspiration from other land use
types predicted by SEBAL also showed reasonable results. Furthermore,
the distribution of ETa in the entire area of the Gezira scheme was also
discussed. This study demonstrates that the remote sensing surface
energy balance model can be used to estimate ETa in large arid
environment such as the Gezira scheme.
Keywords:
Sudan Journal of Agricultural Research Vol. 8 (2007) PP. 77-87
