Space Technology and Geographic Information Systems Applications in adb projects

Contribution of Space Technology
The SEBAL was applied in conjunction with NASA’s Moderate Resolution Imaging Spectrometer (MODIS) 
data aboard the Aqua satellite and routinely measured meteorological data to prepare an analysis of the 
extent and severity of drought in the Cau sub-basin and the Red River basin. 

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Space Technology Applications in Asian Development Bank Projects 
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For each MODIS pixel (1 km resolution) the following hydrological variables were quantified:
(i) actual evapotranspiration,
(ii) potential evapotranspiration,
(iii) soil moisture, and
(iv) biomass production.
These distributed hydrological variables will be used to compute a composite water stress index. With 
these data, current water balances for the different sub areas of the Cau sub-basin can also be evaluated.
Results
The remote sensing drought analysis resulted in the following conclusions:
(i) the Cau sub-basin is drier than other irrigated areas in the delta;
(ii) the majority of the irrigated areas have a real water deficit of 50 millimeter (mm), which implies 
a very mild stress only;
(iii) water shortages in irrigation systems occur mainly in the central-west and northern part of the 
Cau sub-basin;
(iv) although upland forest systems have real water deficits of 100 mm–200 mm, biomass production 
is not affected, which is possibly related to ecosystem adaptation;
(v) the Cau sub-basin is not exposed to any systematic physical land degradation. To the contrary, 
fractional vegetation cover in both the wet and dry season has increased by 4% over the last
23 years.
W
A
TER RESOUR
CE 
MANA
GEMENT

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Space Technology and Geographic Information Systems Applications in Asian Development Bank Projects