calc_cellarea: Calculate the cell area of LPJmL cells

In lpjmlkit: Toolkit for Basic LPJmL Handling

Calculate the cell area of LPJmL cells

Description

Calculate the cell area of LPJmL cells based on an LPJmLData object or latitude coordinates and grid resolution. Uses a spherical representation of the Earth.

Usage

calc_cellarea(
  x,
  cellsize_lon = 0.5,
  cellsize_lat = cellsize_lon,
  earth_radius = 6371000.785,
  return_unit = "m2"
)

Arguments

x	LPJmLData object with ⁠$grid⁠ attribute, an LPJmLData object of variable "grid" ("LPJGRID") or a vector of cell-center latitude coordinates in degrees.
cellsize_lon	Grid resolution in longitude direction in degrees (default: 0.5). If x is an LPJmLData object the resolution will be taken from the meta data included in x if available.
cellsize_lat	Grid resolution in latitude direction in degrees (default: same as cellsize_lon). If x is an LPJmLData object the resolution will be taken from the meta data included in x if available.
earth_radius	Radius of the sphere (in m) used to calculate the cell areas.
return_unit	Character string describing the area unit of the returned cell areas. Defaults to "m2", further options: "ha" or "km2".

Value

A vector or array matching the space dimension(s) of x if x is an LPJmLData object. A vector of the same length as x if x is a vector of latitude coordinates. Cell areas are returned in the unit return_unit.

Examples

grid <- matrix(
  data = c(-179.75, 89.75, -0.25, 0.25, 0.25, -0.25, 179.75, -89.75),
  ncol = 2,
  byrow = TRUE,
  dimnames = list(NULL, c("lon", "lat"))
)
gridarea <- calc_cellarea(grid[,"lat"])

lpjmlkit documentation built on March 31, 2023, 9:35 p.m.