Nabil
You only need to specify coordinates if you don't want to generate weather files for all MERRA2 cells.
If you do want to specify coordinates you input a string of latitude and longitude pairs separated by commas with no intervening spaces. For example '1,2,1.5,2.3'. I will be making it a little more forgiving on spaces etcetera and improving the help. You can contact me at siren@sen.asn.au if you need more specific help on SIREN.
Kind regards
Angus
