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|- |-
| Radiation (MJ/m<sup>2</sup> | Radiation (MJ/m<sup>2</sup>
-| Maximum and minimum temperature+| Global radiation
-| Some ET<sub>0</sub> calculation methods use average temperature only. AgrometShell needs both minimum and maximum temperatures.+| Global radiation can be calculated from sunshine hours or sunshine fraction accompanied by latitude and day in the year (Julian Date).
 +|-
 +| Wind Speed (m/sec>
 +| Wind speed at 2 meters
 +| Formulas are available to convert wind speed for other heights (e.g. 10 meters) into a 2 meter value.
|- |-
|} |}

Revision as of 08:31, 4 August 2006

Chapter 11. Development of ET0 computation procedure.

Potential evapotranspiration (ET0) is a vital input to Water Balance calculations, which in turn are a vital part in Crop forecasting. The parameters needed to calculate ET0 are the following:

Parameter group Parameters Remarks
Temperature Maximum and minimum temperature Some ET0 calculation methods use average temperature only. AgrometShell needs both minimum and maximum temperatures.
Radiation (MJ/m2 Global radiation Global radiation can be calculated from sunshine hours or sunshine fraction accompanied by latitude and day in the year (Julian Date).
Wind Speed (m/sec> Wind speed at 2 meters Formulas are available to convert wind speed for other heights (e.g. 10 meters) into a 2 meter value.


  • Temperatures : minimum and maximum in degrees celcius
  • Radiation. Radiation can be calculated quite accurately from the number of sunshine hours (or sunshine fraction) accompanied by Day number in the year





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