I’m running the coastal blue carbon model (3.8) to investigate future carbon fluxes with sea level rise (reflecting a combination of processes including upland marsh migration, marsh drowning, and vertical accretion of marshes). The model ran successfully, but I have a few questions about the outputs.
The carbon_emissions_between_2050_and_2120.tif output looks reasonable for most of the habitat types, but a very high value of 23922938 for the pixels that represent marsh that drowned due to SLR between 2050 and 2120. This value is much higher than expected (the carbon stock at 2050 for the same pixels is 0.000891, so they shouldn’t be able to emit more than that, right?).
I’m confused about the timing of transitions and how that is reflected in the carbon accumulation and emissions rasters. I thought that transitions occurred in the year they appear in a habitat raster - for example, if a non-blue carbon habitat in the baseline raster transitioned to a blue carbon habitat in 2050, then that pixel wouldn’t accumulate any carbon between the baseline year and 2050. However, the carbon accumulation raster from the baseline to 2050 has positive values for these types of pixels that is the same as the value for pixels that started out and remained a blue carbon habitat. Similarly, the carbon stock at 2050 raster shows that these pixels have some carbon stored, even though I would expect them to have 0 carbon stock until the next timepoint after they transitioned to a blue carbon habitat. Is this something that has changed from previous versions of the model?
Thanks; I can share screenshots or outputs to illustrate either of these if that would be helpful.