This post outlines a process chain for organising reference evapotranspiration data over Sub Saharan Africa using Karttur´s GeoImagine Framework. The results are used for calculating regional water balances as outlined in the next post.
The FAO dataset on reference evapotranspiration (refET) is composed of monthly average layers representing 1961 to 1990. The refET varies dependent of many factors, including temperature, wind and atmospheric water vapor pressure, but for this study you will use monthly average data. The alternative, to calculate dynamic refET is complicated and the data demands exceeds the available.
Process chain
In the Framework, a process chain can be built as a series of calls to xml coded instructions. The process chain calls are under the Hide/Show button below and the remaining parts of the post details each called xml.
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### FAO refET processing ###
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## The processing requires that the FAO reference evapotranspiration is captured and organized ##
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### Update db ###
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## If you have access to TRMM data created by karttur's Geoimagine Framework ##
## you can access the data from your Framework installation by updating the db ##
## You can also use updatedb to clean your database and/or delete files from your Framework organized storage ##
## Update db for FAO refET, if needed ##
#FAOrefET-0190_udatedb.xml
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### Tile to region ###
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## Tile FAO refET to region ##
#AfricaSubSahara_FAOrefET-0160_tile_staticM.xml
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### Archive ###
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## Archive ##
#AfricaSubSahara_FAOrefET-0980_arcihive-zip_staticM.xml
Tile to region
In this project the dominating tile system is the MODIS SIN grid dividing the earth in 36 horizontal and 18 vertical tiles.
