International Registry of Evapotranspiration Measurements

[Dr. Richard G. Allen]

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To:  IR-L and SOWACS subscribers  (I apologize for the cross-
postings)

I would like to take this opportunity to announce an Internet database 
on Evapotranspiration that is now available for development.  The 
name of the database is the ģInternational Registry of 
Evapotranspiration Measurements.ī As the name implies, the 
database is actually more of a register of names and locations of 
contacts who hold evapotranspiration data.  It does not hold the data 
themselves.

The International Registry of Evapotranspiration Measurements 
(IREM) was proposed by the International Commission on Irrigation 
and Drainage ń Working Group on Sustainable Crops and Water Use 
and by officials within FAO.  The website for IREM has been created 
and will be maintained by the Institut National de la  Recherche 
Agronomique (INRA) of France.  Dr. Frederic Huard of INRA is the 
primary contact for the registry, under the general direction of Dr. 
Bernard Itier of INRA, Dr. Richard G. Allen of Univ. Idaho and Mr. 
Martin Smith of FAO.

The address of the IREM site is:
{ HYPERLINK http://www.avignon.inra.fr/ET/ }http://www.avignon.inra.fr/ET/


The following narrative is taken from the IREM home page:
--------------------------------
The idea to create a web site for evapotranspiration  measurements 
and data was born during the 48th  Executive Council Meeting of the 
ICID in Roma in  1997. The French agronomic institute (INRA) 
volunteered to support this operation, in collaboration
with some scientists of world-wide institutes.  This registry does not 
contain any actual data, but is intended to provide users with 
information describing the type of evapotranspiration measurements, 
method used, period of measurements, vegetation type, and the data 
availability and cost.

 This endeavor, web site, and organisations do not entertain any 
responsability for the correctness of information contained in this 
registry nor for the accuracy or reliability of any data that are 
described.
--------------------------------

As the narrative indicates, the intent is to present names and 
locations of contacts along with the general description of the type of 
data that is available.  The distribution and dissemination of any data 
is completely between individuals and will occur outside of IREM.  
IREM wishes to serve the purpose of bringing together individuals or 
ministries that hold various data on evapotranspiration and individuals 
who desire to obtain ET information for use in developing or applying 
various models or studies.

The general categories within IREM for classifying ET information 
are: 1) Lysimeter; 2) Bowen Ratio; 3) Eddy Covariance; 4) Profile and 
5) Water Balance.  The Water Balance category includes ET 
determined from soil water balances derived from gravimetric, neutron 
probe, TDR, or other soil profile measurements.  Entered data are 
sorted according to measurement type, crop, and country of origin.

The way the registry works is that a ģholderī of data enters 
information describing his or her data onto special forms presented at 
the IREM web site.  This information is then submitted via the 
Internet to IREM and is processed manually by INRA personnel.  
After processing and error checking, the information is placed into 
the IREM database so that it can be viewed world-wide via the 
internet.  The information includes how the ET data are to be 
distributed, restrictions on the data usage and any costs associated 
with the procurement (charged by the holder of the data).

There is no charge for listing information with IREM.  The cost for the 
web site and data base maintenance are currently underwritten by 
the Institut National de la  Recherche Agronomique (INRA) of France.

All users are cautioned that no data are entered nor kept at the IREM 
web site.  Therefore, the registry has no means to validate or to 
determine correctness or the representativeness of ET data that are 
offered via IREM.  ET data are notoriously subject to a wide range of 
errors and biases that include errors and biases in instrumentation 
calibration, errors in equipment design, errors in equipment 
operation, errors or biases in weather data associated with the ET 
data, poor management of vegetation within a lysimeter or soil profile 
measuring site, and biases in the water and fertility management of 
the measured vegetation relative to typical vegetation in agriculture.  
Because of all of these potential errors and biases, ET data collected 
by others should be used with skepticism and caution.  Data should 
be validated using whatever means are available.  As a conservative 
estimate, probably 3/4 of all ET data available have significant biases 
and errors that should disclude them from being considered for use 
to calibrate mathematical models.  Never the less, in spite of these 
shortcomings in ET data, the IREM registry will function as a registry 
for ET data in hopes that it will connect valid data with valid uses.

The information for the manager of IREM, Dr. Frederic Huard, is the 
following:

Address
INRA
147, rue de l'Universite
75 338 PARIS cedex 07
FRANCE 
Phone +33 01 42 75 90 00 
Fax     +33 01 47 05 99 66
E-Mail  huard@avignon.inra.fr


Thank you.

Dr. Richard G. Allen, advisor to IREM
Professor of Water Resources Engineering
University of Idaho
Kimberly, Idaho