Compute a delta raster.

This function generates a delta (difference) raster, computed as the difference between model estimates (x) and some observations (high_res_obs). x is a terra::SpatRaster of the variable we want to downscale, and it can contain multiple time steps. ref_time sets the time slice for which the delta should be computed.

Usage

delta_compute(x, ref_time, obs, max_land = NULL)

Arguments

x

a terra::SpatRaster for the variable of interest, with all time steps of interest

ref_time

the time (BP) of the slice that is used to compute the delta

obs

the observations

max_land

a terra::SpatRaster with the maximum land extent

Value

a terra::SpatRaster of the delta

Details

If obs has a higher resolution than x, the latter is interpolated using a bilinear algorithm. For areas that are present in some time slices, but not in the observations (e.g. due to sea level change), the delta map is extended to cover the maximum cumulative land mask (over all time steps) using inverse distance weighted interpolation.