|
Gridded data were generated using the ANU (Australian
National University) 3-D Spline (surface fitting algorithm). The grid point
resolution of the data is 0.1 degrees ( approximately 10km).
As part of the 3-D analysis process a 0.1 degree resolution
digital elevation model (DEM) was used. Approximately 700 stations were used in
the analysis, and all input station data underwent a high degree of quality
control before analysis, and conform to WMO (World Meteorological Organisation)
standards for data quality.
Areal Actual ET is the ET that
actually takes place, under the condition of existing water supply, from an area
so large that the effects of any upwind boundary transitions are negligible and
local variations are integrated to an areal average.
Areal Potential ET is the ET that
would take place, under the condition of unlimited water supply, from an area so
large that the effects of any upwind boundary transitions are negligible and
local variations are integrated to an areal average.
Point Potential ET is the ET that
would take place, under the condition of unlimited water supply, from an area so
small that the local ET effects do not alter local airmass properties. It is
assumed that latent and sensible heat transfers within the height of measurement
are through convection only.
The above definitions are based
on those given by Morton (1983), but we have used the term areal potential ET
for Morton’s wet-environment ET and the term point potential ET for Morton’s
potential ET.
Morton, F.I. (1983). Operational
estimates of areal evapotranspiration and their significance to the science and
practice of hydrology. Journal of Hydrology, 66: 1-76. |
