Question Land Allocation Module ~ Moirai LDS, and land supply

[MarcoLeeHT]

Hello,
I am trying to understand relationship between " Land Allocation Module ~ Moirai LDS"
and how land supply limit is defined.

1. As far as I can understand,
   Land Allocation Module is using result files of Moirai ("Land_type_area_ha.csv", "MIRCA_rfdHA_ha.csv", etc.)
   and Moirai is not running simultaneously inside GCAM.
   Therefore, to change settings of GCAM Land Allocation Module, changing result files of Moirai as GCAM's input is most effective.

   Is it correct?

2. I could find historic cropland area and harvested area as input .csv for GCAM.
   And I can understand that the land use types are competing each other with limited land supply.

   Where can I find input files for total land supply values ?

Thank you for your help.

[kanishkan91]

@MarcoLeeHT moirai is a land data system that just handles historical land allocation for GCAM. Changing moirai outputs will therefore only change calibration values. Note that moirai has its own repo here- https://github.com/JGCRI/moirai

It (moirai) will allocate land balances , carbon balances and crop yields based on the two. GCAM uses that data as a starting point and then produces future projections.

The moirai outputs are all within the input/gcamdata/inst/extdata/aglu/LDS/ folder.

If you want total land allocated historically (I assume this is what you mean by supply? ), you can find that in the file Land_type_area_ha.csv located within the aboive mentioned LDS folder.

Note that land balances are allocated by water basin and land type. So you will need to aggregate as required. The land type mapping can be found in the LDS_land_types.csv

Let me know what you think and let us know if you have any additional questions.

[MarcoLeeHT]

@kanishkan91 Thank you so much for your help.
One quick follow question/confirmation though.

About "Land_type_area_ha.csv"
If the total area of one GLU in the last year, 2016, is 100. (30 for type 2, 30 for type 13, 40 for 32)

Won't GCAM expand or reduce that total area (100) while it conduts future projections?

[kanishkan91]

That's correct. This will change. We store historical data to 2016 but the last historical year used by the model is 2015. If you are interested in the changed values, you can access those in a database post a GCAM run.