Revision as of 08:31, 4 August 2006; view current revision
←Older revision | Newer revision→
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