calc_del13C: Calculate d13C isoscape

In rebeccalpowell/grassmapr: Predict C3/C4 Grass Distribution

Description

Applies simple mixing model to percent vegetation cover layers. User provides d13C endmember values for each plant functional type layer. Function may also be applied to other endmember statistics, such as, endmember standard deviation.

Usage

calc_del13C(pft.cover, d13C.embs, scale.factor = 100, filename = "",
  ...)

Arguments

pft.cover	RasterBrick. Percent cover for each plant functional type, may be result of calc_pft_cover.
d13C.embs	Numeric. Vector of length equal to number of layers in pft.cover. Values correspond to d13C endmembers for each pft.cover vegetation type.
scale.factor	Numeric. Scale factor for vegetation cover values. Default value = 100.
filename	Character. Optional output root filename passed to writeRaster, default output file type is GeoTiff. If not specified, output is written to a temporary file.
...	Other arguments passed to writeRaster.

Value

RasterLayer. Values correspond to mean vegetation d13C (per mil) for each grid cell.

See Also

calc_pft_cover, calc_C4_ratio, overlay.

Examples

# Generate d13C isoscape based on static endmembers:

# User provides PFT layer stack; may be output of calc_pft_cover()
# In this example, pft_cover stack includes: C4 herb, C3 herb, woody layers

# Vector of d13C endmembers
d13C_emb <- c(-12.5, -26.7, -27.0)    # C4 herb, C3 herb, woody

# Apply mixing model using input PFT vegetation layers
d13C_iso <- calc_del13C(pft_cover, d13C_emb)

# Plot d13C isoscape
plot(d13C_iso)

# Calculate weighted standard deviation of mean d13C value:

# Vector of (2x) d13C endmember std. dev. for each vegetation layer
d13C_emb_std <- c(2.2, 4.6, 3.4)      # C4 herb, C3 herb, woody

# Apply mixing model using input PFT vegetation layers
d13C_iso_std <- calc_del13C(pft_cover, d13C_std)

# Plot standard deviation layer
plot(d13C_iso_std)

rebeccalpowell/grassmapr documentation built on June 20, 2019, 8:07 p.m.