Skip to main content

Empirical Methods of Estimating or Predicting Evapotranspiration Using Radiation

Jensen, Marvin E. (1967) Empirical Methods of Estimating or Predicting Evapotranspiration Using Radiation. pp. 49-53,64. In: Proc. ASAE Conf. "Evapotranspiration and Its Role in Water Resources Management". USA-IL-Chicago, 1966/12/05-06.

[img] PDF

Download (425kB)


PREDICTIONS of evapotranspiration
are basic parameters for the engineer
or agronomist involved in planning
and developing water resources.
Estimates of evapotranspiration are also
used extensively in assessing the irrigation
water-management efficiency of existing
projects, future project drainage
requirements, and the magnitude of
deep percolation losses under existing
management practices. Water delivered
to farms and fields must provide for
evapotranspiration and unavoidable percolation
beyond the root zone due to
unsaturated flow caused by gravity. The
first is dependent on meteorological conditions
and the vegetative characteristics
of the crop when water is not limiting.
The second is dependent on management
such as the amount of excess
water applied by rainfall or irrigation,
or the moisture level maintained, and
it is not directly dependent on meteorological
conditions. Actually the relative
amount of deep percolation between
irrigations under common practices
is more apt to be inversely rather
than directly related to evapotranspiration.
Measurement of irrigation water
delivered to an area and surface runoff,
coupled with reliable estimates of evapotranspiration,
provide the most practical
estimates of deep percolation under
existing management systems. Full
utilization of water resources will require
more reliable estimates of evapotranspiration
in the future, and these
estimates must not include deep percolation.

Item Type: Conference or Workshop Item (Paper)
NWISRL Publication Number: 0081
Subjects: Water > Evapotranspiration
Research methodology
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:57
Last Modified: 15 Mar 2017 21:52
Item ID: 1063