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==3.3. Preparing and using the dekadal rainfall and ET<sub>0</sub> database for crop monitoring== | ==3.3. Preparing and using the dekadal rainfall and ET<sub>0</sub> database for crop monitoring== | ||
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Crop forecasting based on water balance calculations is usually done in a ten-day timestep. A ten day period is called a “dekad”. However, should daily weather data of good spatial and temporal extend be available, the water balance can be run in AgrometShell on a daily basis. | Crop forecasting based on water balance calculations is usually done in a ten-day timestep. A ten day period is called a “dekad”. However, should daily weather data of good spatial and temporal extend be available, the water balance can be run in AgrometShell on a daily basis. |
Revision as of 14:26, 27 September 2006
3.3. Preparing and using the dekadal rainfall and ET0 database for crop monitoring
Peter Hoefsloot Crop forecasting based on water balance calculations is usually done in a ten-day timestep. A ten day period is called a “dekad”. However, should daily weather data of good spatial and temporal extend be available, the water balance can be run in AgrometShell on a daily basis.
In order to do crop forecasting the following weather data have to be gathered:
- Actual decadal rainfall data for the running season.
- Actual decadal ET0 data for the running season
- Normal rainfall data
- Normal ET0 data
These data form indicators in itself, even without using them directly in a water balance calculation. Some examples are given below:
A simple rainfall map for the current dekad
Accumulated rainfall from the beginning of the season
Excel is needed to do the accumulation.
An accumulated rainfall image
By applying interpolation to the total rainfall amounts calculated in the previous step, an image is created.
An improved accumulated rainfall image (using SEDI with altitude)
The image in the previous paragraoh can be improved with tye application of a DTM. The DTM (altitude) constitutes a background factor that helps the interpolation. The assumption is that the higher the altitude, the higher the rainfall.