Dear friends
I have been using the Coastal Blue Carbon model and valuation in two different Blue Carbon classes. In the carbon stock raster, I am getting two different values corresponding to two blue carbon LULCs.
I was running the valuation using price, interest rate and discount rate data.
However, ‘Net Present value raster’ and ‘total net carbon sequestration between years xxx and xxx’ are coming with single raster values (i.e. 0 and yy).
Theoretically, it should produce two different values (i.e. 0, yy and zz) corresponding to two different blue carbon LULCs.
Any insights pls.
Net Present Value will be 0 if the sequestration value is 0. If “total net carbon sequestration” is also 0 when you don’t expect it to be, then we need to figure out why that is.
Are you using two different “snapshot” LULC rasters? Or a single LULC raster that has two classes that are considered blue carbon?
Do the “carbon_stock” rasters for each of the years have the same value every year for that LULC class? If so, that indicates that nothing is changing between years, so the model does not think that there’s any LULC change, accumulation or emission happening. Do you see anything in your input tables (LULC lookup table, biophysical table or transitions table) that explains this?
As such, the Total net carbon sequestration is not 0.
The values are 0 for non-Blue carbon LULCs but it is xxx for blue carbon classes.
My concern is that I am using two different Blue carbon LULC classes for which different values have been provided in the biophysical table.
How do all blue carbon pixels have the same net carbon sequestration value?
I am using two different “snapshot” LULC rasters (year 2024 and year 2035), which show a slight increase from one Blue carbon LULC to another Blue carbon LULC.
The “carbon_stock” rasters for years (2024 and 2035) do not show the same values.
Carbon stock raster 2024: 3 values (0 for non Blue Carbon LULCs; XX for blue carbon lulc1 and yy for blue carbon lulc2)
Carbon stock raster 2035: 4 values (0 for non Blue Carbon LULCs; XX for blue carbon lulc1 and yy for blue carbon lulc2 and zz in few pixels which are of non blue carbon LULCs ??)
I am attaching all the necessary files for you to review;
Thanks for providing the outputs @Kantharajan. It’s not obvious to me from these layers why there is a single value for sequestration, that does seem strange. I’ll need to look at your input data to figure out what’s going on, both the inputs for pre-processor and main model. You might be able to upload the data here if the zip file is small enough, or if it’s better to upload to a sharing service (Google, Dropbox, whatever) that works too. If you don’t want to post the URL here, you can send it to swolny@stanford.edu.
Thanks for sending your input data @Kantharajan. Looking at the biophysical table, both of the blue carbon classes (dense mangrove and sparse mangrove) have the same values for the different accumulation parameters, and their disturbance values are also the same. Since sequestration accounts for the change over time (accumulation - emissions), if the accumulation and emission rates are the same for both classes, they will have the same sequestration values at the end of the time period you’re evaluating. See what happens if you change the accumulation values for one of those blue carbon classes, I suspect that you’ll see a difference in the resulting maps.
