The widely-applied Surface Energy Balance Algorithm for Land (SEBAL) for computing ET across vast heterogeneous landscapes is the most relevant operational algorithm. SEBAL uses satellite data and routine ground-based weather data. A fundamental component of the SEBAL model is the use of thermal infrared spectral measurements for determining surface temperature and by which to express the ratio between sensible and latent heat fluxes. SEBAL has been applied in more than 30 countries world wide. More information on project references and basins references can be found at www.waterwatch.nl and www.sebal.us. SEBAL is able to compute the following physical processes and spatial variables:
SEBAL is essentially applied with NASA-borne satellites measuring reflectance in the visible, near infrared and thermal infrared parts of the spectrum (e.g. Landsat, MODIS,). These data are obtained for each individual satellite image that is available for an area. By combining several individual images into a time series, one can create a monitoring system to detect where and when areas become water short or mis-utilize these precious water resources.
SEBAL outputs are used to calibrate the drought monitoring system.
