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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”. 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: | In order to do crop forecasting the following weather data have to be gathered: | ||
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* Normal rainfall data | * Normal rainfall data | ||
* Normal ET<sub>0</sub> data | * Normal ET<sub>0</sub> data | ||
+ | The previous chapter has shown how a database of weather data can be established. | ||
- | These data form indicators in itself, even without using them directly in a water balance calculation. Some examples are given below: | + | ===Weather data as indicators=== |
- | ===A simple rainfall map for the current dekad=== | + | Weather data form simple indicators in itself, even without using them directly in a water balance calculation. Some examples are given below: |
+ | |||
+ | ===Example 1: Preparing a simple rainfall map for the current dekad=== | ||
{|"class=prettytable" cellpadding="15" border="1" style="border-collapse:collapse" | {|"class=prettytable" cellpadding="15" border="1" style="border-collapse:collapse" | ||
- | |width="300"| Start the “Database-Map” function. This example will display rainfall data for a specific dekad in 2002 for Bangladesh.||[[Image:graph37.jpg|400px|]] | + | |width="300"| Start the “Database-Map” function. This example will display rainfall data for the first dekad of May in 2002 for Bangladesh.||[[Image:graph37.jpg|400px|]] |
|--- | |--- | ||
|width="225"|With the world map as default, some cluttered data are shown for Bangladesh ||[[Image:graph38.jpg|400px|]] | |width="225"|With the world map as default, some cluttered data are shown for Bangladesh ||[[Image:graph38.jpg|400px|]] | ||
|--- | |--- | ||
- | |width="225"|Using the zoom buttons an image for just Bangladesh is selected. With the ''Copy-to-clipboard'' button this image can be copied to the clipboard and pasted into a word processor. ||[[Image:graph39.jpg|300px|]] | + | |width="225"|Applying the zoom buttons results in an image for Bangladesh. With the ''Copy-to-clipboard'' button this image can be copied to the clipboard and pasted into a word processor. ||[[Image:graph39.jpg|300px|]] |
|} | |} | ||
- | ===Accumulated rainfall from the beginning of the season=== | + | === Example 2: Calculating accumulated rainfall from the beginning of the season=== |
+ | |||
+ | Microsoft Excel is needed to do the accumulation. Therefore the data are exported to Excel. | ||
- | Excel is needed to do the accumulation. | ||
{|"class=prettytable" cellpadding="15" border="1" style="border-collapse:collapse" | {|"class=prettytable" cellpadding="15" border="1" style="border-collapse:collapse" | ||
- | |width="300"| In this example the accumulated rainfall for the season 1991-1992 is calculated. The example is for Zimbabwe where the season starts around November. The current dekad is assumed to be the second dekad of March 1992. Start the “Database-Export” function. Start a new export format||[[Image:graph40.jpg|400px|]] | + | |width="300"| In this example the accumulated rainfall for the season 1991-1992 is calculated. The example is for Zimbabwe where the season starts around November. The current dekad is assumed to be the second dekad of March 1992. Start the “Database-Export’’ function. Start a new export format||[[Image:graph40.jpg|400px|]] |
|--- | |--- | ||
|width="300"|A list containing Zimbabwean stations is selected. ||[[Image:graph41.jpg|400px|]] | |width="300"|A list containing Zimbabwean stations is selected. ||[[Image:graph41.jpg|400px|]] | ||
|--- | |--- | ||
- | |width="300"|All stations in the list are presented. Now add columns with the Add button. ||[[Image:graph42.jpg|400px|]] | + | |width="300"|All stations in the list are presented. Now add columns with the ‘’Add’’ button. ||[[Image:graph42.jpg|400px|]] |
|--- | |--- | ||
- | |width="300"|Specify the meteorological parameter to export. In this example 3 columns are exported added at the same time.||[[Image:graph43.jpg|400px|]] | + | |width="300"|Specify the meteorological parameter to export (Rainfall). In this example 3 columns are exported added at the same time.||[[Image:graph43.jpg|400px|]] |
|--- | |--- | ||
- | |width="300"|The same is done for all dekads until the current one (Dekad 2 of March 1992). When ready press next ||[[Image:graph45.jpg|400px|]] | + | |width="300"|The same is done for all dekads until the current one (Dekad 2 of March 1992). When ready press ‘’Next’’ ||[[Image:graph45.jpg|400px|]] |
|--- | |--- | ||
|width="300"|Select Export to Excel||[[Image:graph46.jpg|400px|]] | |width="300"|Select Export to Excel||[[Image:graph46.jpg|400px|]] | ||
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|width="300"|All data are presented in Excel||[[Image:graph47.jpg|400px|]] | |width="300"|All data are presented in Excel||[[Image:graph47.jpg|400px|]] | ||
|--- | |--- | ||
- | |width="300"|The totals are added using Excel formulas.||[[Image:graph48.jpg|400px|]] | + | |width="300"|The totals are calculated using Excel formulas.||[[Image:graph48.jpg|400px|]] |
|--- | |--- | ||
|} | |} | ||
- | ===An accumulated rainfall image=== | + | === Example 3: An accumulated rainfall image=== |
By applying interpolation to the total rainfall amounts calculated in the previous step, an image is created. | By applying interpolation to the total rainfall amounts calculated in the previous step, an image is created. | ||
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|width="300"| Using the ''Interpolate-Inverse Distance'' function, the CSV file can be interpolated to an image. ||[[Image:graph50.jpg|400px|]] | |width="300"| Using the ''Interpolate-Inverse Distance'' function, the CSV file can be interpolated to an image. ||[[Image:graph50.jpg|400px|]] | ||
|--- | |--- | ||
- | |width="300"| The result is an image. This gives a much more visual picture of the cumulative rainfall.||[[Image:graph51.jpg|400px|]] | + | |width="300"| The result is an image. This provides a much more visual picture of the cumulative rainfall.||[[Image:graph51.jpg|400px|]] |
|--- | |--- | ||
|} | |} | ||
- | ===An improved accumulated rainfall image (using SEDI with altitude)=== | + | === Example 4: 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. | + | The image in the previous paragraph can be improved with the 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. |
Current revision
[edit]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”. 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
The previous chapter has shown how a database of weather data can be established.
[edit]Weather data as indicators
Weather data form simple indicators in itself, even without using them directly in a water balance calculation. Some examples are given below:
[edit]Example 1: Preparing a simple rainfall map for the current dekad
[edit]Example 2: Calculating accumulated rainfall from the beginning of the season
Microsoft Excel is needed to do the accumulation. Therefore the data are exported to Excel.
[edit]Example 3: An accumulated rainfall image
By applying interpolation to the total rainfall amounts calculated in the previous step, an image is created.
[edit]Example 4: An improved accumulated rainfall image (using SEDI with altitude)
The image in the previous paragraph can be improved with the 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.