|WORLD METEOROLOGICAL ORGANIZATION||
|Explanation of the criteria for classification and numbering of components||
|Explanation of the dates on the component's description|
1. Purpose and objectives
used to measure daily amount of water lost through evaporation.
The instrument consists of the following items:
U.S. Class "A" evaporation pan with standard dimensions
The pan is
installed on a wooden platform set on the ground with natural grass
condition. The exposure of the pan should be free from obstructions
that cast shadows over the pan. To measure the evaporation, a
graduated measuring can having a surface area 1/100 that of the pan is
added or removed from the pan.
evaporation measured by the appointed observer.
5. Operational requirements and restrictions
manual rain gauge should be installed alongside the evaporation pan.
This is to facilitate the calculation of daily evaporation on days
when rainfall occurs during the day. For installation of rain gauge,
please refer to HOMS component C27.1.02. The pan should be cleaned as
frequently as necessary to keep it free from sediment, scum and oil
films. Inspection for leaks should be carried out regularly as leaks
will render the measurements of no use.
6. Form of presentation
drawings for local manufacture are available.
7. Operational experience
It has been
used satisfactorily as a standard instrument for daily evaporation
measurements for a few years by the Drainage and Irrigation
8. Originator and technical support
Irrigation Department, Malaysia.
10. Conditions on use
Technical drawings available free of charge. Purchase of the instrument, either complete or as individual items, from the local manufacturer in Malaysia can be arranged.
|(First entered: 6 MAR 81||
Last updated: 28 MAY 99)