raincorrect: Calculates elevation correction factor to apply to...

In ilyamaclean/ecohydrotools: hydrogical modelling for ecological applications with R

Description

raincorrect Calculates an altitudinal correction factor for application to fine-resolution e.g. daily rainfall derived using bilinear interpolation.

Usage

raincorrect(demc, demf, rainc, rainf)

Arguments

demc	a coarse-resolution raster of digital elevation data
demf	a fine-resolution raster of digital elevation data for the region for which correction factors are required
rainc	a coarse-resolution raster of e.g. monthly or annual rainfall covering the same extent as demc
rainf	a fine-resolution raster of e.g. monthly or annual rainfall derived by resampling coarse-resolution rainfall data, covering the same extent as demf.

Details

Fine-scale e.g. daily or hourly ainfall data derived by resampling or interpolating coarse-resolution data fails to adequately capture elevation effects on rainfall. This function fits a thin plate spline model fitted to coarse-resolution rainfall data with elevation as a predictor. The model is then applied to fine-resolution data and the results compared to those obtained using simple raster resampling using bilinear interpolation. The correction factor can then be applied to e.g. daily rainfall.

Value

a raster of correction factors

Examples

rainf <- resample(cornwallrain, dtm100m)
plot(mask(rainf, dtm100m)) # rainfall derived using bilinear interpolation
cf <- raincorrect(dtm1km, dtm100m, cornwallrain, rainf) # takes ~ 20 seconds to run
plot(rainf * cf) # rainfall with correction factor applied

ilyamaclean/ecohydrotools documentation built on June 10, 2019, 5:45 a.m.