RA parameter (ETo for Annual Water Yield)

Science, Research & Data
1

Dear Natural Capital,

I am working with the annual water yield model, and I want to obtain the RA parameter to estimate ETo (from the modified Hargreaves equation), and I have seen that this can be obtained from GIS relatively easily.

  1. What tool is it?
  2. Is it available in QGIS?
  3. Do you know of any forum post that has information on the procedure?

Thank you very much for your reply.

2

Hi @bmnoz_2001, I’m not sure exactly what procedure you are looking for, but if you search this forum for “extraterrestrial radiation”, you’ll find several discussions of this issue and various ways to go about obtaining RA (extraterrestrial radiation) values.

If you are hoping for a QGIS tool, you might try searching the QGIS docs (and/or the web) for information about creating a “solar radiation” layer.

If you want to use a table to find values for the latitude closest to your area of interest, you can refer to these Meteorological Tables from the FAO (specifically Table 2.6).

I hope this helps!

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