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openmodels / META-2021

The Model for Economic Tipping (point) Analysis
GNU General Public License v3.0
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Floor VGIS at zero #13

Closed pwaidelich closed 9 months ago

pwaidelich commented 9 months ago

The VGIS variable in src/components/GIS.jl denotes the "volume of the GIS relative to initial volume" in %, but it can currently reach negative values for outlier Monte Carlo runs. Flooring VGIS at zero resolves this issue.

Since the difference in VGIS between timesteps (Diff_VGIS) is a product of multiple terms including vv.VGIS[tt-1] ^ pp.expvol, the floor also ensures that Diff_VGIS will be equal to zero once the zero lower bound is reached

jrising commented 9 months ago

@pwaidelich Thanks for tracking this down.

@sidietz79 Our Excel model doesn't have this constraint, so I think we were just dropping those MCs. But this seems like an easy fix. Any objections?

sidietz79 commented 9 months ago

No objections @jrising . Those runs would have been dropped if they returned an error somewhere, if not then potentially in the process of trimming the distribution, but this is not very likely given the small magnitude of SLR damages relative to temperature. Bill didn't have a constraint on this but then he didn't explore the extremities of the parameter space. Thanks @pwaidelich for picking this up.