Opened 15 months ago

Last modified 14 months ago

#3324 accepted error

Carry irrigation through (re)start from dump

Reported by: mtodt Owned by: pmcguire
Component: JULES Keywords: irrigation start dump JULES UM
Cc: Platform: JASMIN
UM Version:


This is more an open deposit of information and notes than asking for help.

I'm running JULES (and soon UM) simulations with irrigation activated, e.g. in suite u-bi733. I'm using settings irr_crop=1 and l_irrig_limit=.true., which means that the irrigation amount is limited by water availability and that an irrigation season, prescribed as 150 days long, is calculated for each grid cell based on meteorological conditions.
I noticed that every time a run is restarted (or started) from a dump, there is no irrigation during the first year. I suspect that the one-year break after restarting indicates that the irrigation scheme cannot calculate or complete a 150-day irrigation season and so needs to start "afresh" with its calculation. For some regions, e.g. in India, the calculated irrigation season lasts from the end of one year into the next. In those cases the irrigation season is "finished" early in the second year as if the irrigation scheme continues an imaginary irrigation season. So, the timing of an irrigation season is not affected by this issue, it's just that the first year is basically cut out.
The solution for this would be to include an irrigation timing-related variable in dumps. Does that already exist?

Change History (5)

comment:1 Changed 14 months ago by pmcguire

  • Status changed from new to accepted

Hi Markus
You said this was more for information archiving than for asking for help.
But I note that you did have a question. Did you figure out an answer to your question?

comment:2 Changed 14 months ago by mtodt

Hi Patrick

More or less. For now, option irr_crop=1 will not be implemented in the UM, only the year-round irrigation option irr_crop=0. So, while the issue won't occur for the foreseeable future, it won't be solved either.


comment:3 Changed 14 months ago by pmcguire

Thanks, Markus
Do you want to leave this ticket open, so that you/we can add to it later?

comment:4 Changed 14 months ago by mtodt

Well, it'll take a while until we run UM simulations with irrigation, so I won't have any short-term additions. If it makes more sense, we can close it now and reopen it again later.


comment:5 Changed 14 months ago by pmcguire

I think it's ok to keep the ticket open.

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