Carbon stock formulas and IPCC Approach 1 uncertainty per land use

Builds, for each period and land use of the carbon table, the carbon stock formula and its variance and relative uncertainty formulas (IPCC 2006, Vol. 1, Ch. 3, Eq. 3.1 and 3.2).

         Each stock is written as \code{C = CF * S_DM + S_C}, with
         \code{S_DM} the sum of pools in dry matter and \code{S_C} the sum
         of pools in carbon. CF is factored once, so its uncertainty is
         not counted as independent across pools:

         \code{Var(C) = CF^2 * V_DM + (CF * CF_U * S_DM)^2 + V_C}

         with \code{V_S = sum((X * X_U)^2)} over the pools of \code{S}.
         With RS, AGB becomes \code{AGB * (1 + RS)} with variance
         \code{(AGB * (1 + RS) * AGB_U)^2 + (AGB * RS * RS_U)^2}, and BGB is
         ignored. If \code{ALL} is given, it replaces the other pools.

         \code{c_tot_U = sqrt(Var(C)) / C}, simplified with the product
         rule when the stock is a product (one pool, or DM pools only),
         e.g. \code{sqrt(AGB_U^2 + (RS / (1 + RS) * RS_U)^2 + CF_U^2)}.

         Evaluate with each element and its relative uncertainty as
         \code{<element>} and \code{<element>_U} (se / mean). Land uses
         without pools (e.g. DG_ratio only) return NA.

Usage

fct_cstock_formula2(.carbon)

Arguments

.carbon

Carbon table, from fct_checkinput()$data$carbon.

Value

A tibble with c_period, c_lu, c_tot (stock), c_tot_V (variance) and c_tot_U (relative uncertainty).

Examples

path    <- system.file("extdata/mocaredd-templatev2-simple.xlsx", package = "mocaredd")
checked <- fct_checkinput(.path = path)
#> Loading data... - progress: 0%.
#> ✓ Tables loaded successfully from template v2
#> Checking column names... - progress: 14%.
#> ✓ Column names: all required columns present
#> Checking table dimensions... - progress: 29%.
#> ✓ Table sizes: all tables have sufficient rows
#> Checking column data types... - progress: 43%.
#> ✓ Data types: all columns have correct data types
#> Checking category values... - progress: 57%.
#> ✓ Category values: all categories are valid
#> Checking unique IDs... - progress: 71%.
#> ✓ Unique IDs: no duplicates or missing IDs found
#> Checking cross-table and intra_table consistency... - progress: 86%.
#> ✓ Cross-table consistency: all references match
#> -- All checks passed.
fct_cstock_formula2(checked$data$carbon)