30 day months are assumed for f_frost about r3pg HOT 5 CLOSED

Hi @twest820

Thank you for finding this interesting issue. Indeed the manual of the 3-PG is declaring the number of days per month.

However, if you look at the code itself (also of 3-PGpjs which can be downloaded here https://3pg.forestry.ubc.ca/software/) it will be recognised that the same formula as in r3PG or 3PGmix is used for the frost days, see below:

'calculate frost modifier
 fFrost = 1 - kF * (FrostDays / 30)

Since we were translating the code and aimed to test compatibility it was done the same way as in the original model.

I fully support your suggestions for improvements. Please feel free to create a new branch an make a push request to incorporate the changes.

Unfortunately from my side there is very little time to allocate for it.

3PGpjs27.zip

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Yeah, I know how that goes. Thanks Volodymyr, I'll address this in my branch but, as I'm not coding in Fortran, a pull request is unlikely to materialize. A daysInMonth(month) lookup, as done elsewhere in the existing code, would address this. Modulo the leap year issue I'm about to capture, anyways.

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I'll address this in my branch but, as I'm not coding in Fortran

So is your intension to write model fully in R or other language? Would be great if you implement all your detailed comments and suggestions into the code!

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I think it's most accurate to say I'm looking into an experimental version for evaluating certain possibilities. Definitely not funded for anything like an R package though it's possible that, if things go well, the code might eventually become of wider interest. If that happens I'll follow up with you (most likely in email) but I anticipate it will be at least several months to find out, possibly well into next year.

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I have now implemented the number of days per month to calculate the f_frost

Additionally add the check to the prepare_climate function to limit the frost_day to the maximum possible

@DavidForrester this slightly however impacted the output of the model. Particularly it has deviated the biomass outputs by third digit for the stem biomass. The general pattern remain unchanged.

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