Calculation of SSEBI and Evaporative Fraction from Raster Data.

ssebiEF Package

The ssebiEF package provides tools to calculate the Simplified Surface Energy Balance Index (SSEBI) and the Evaporative Fraction (EF) from raster data. It utilizes albedo and surface-air temperature difference (TS-TA) to generate the SSEBI or EF raster.

Installation

You can install the development version of ssebiEF directly from your local folder:

Requirements

• The input rasters (TS and TA) must have the same unit of measurement (Kelvin preferably) to ensure accurate calculations of TS-TA and Simplified Surface Energy Balance Index (SSEBI) or the Evaporative Fraction (EF).

• The input rasters (albedo and TS-TA) must:

  • Have the same Coordinate Reference System (CRS).
  • Cover the same geographic extent.

• If these conditions are not met, the function attempt to align the rasters automatically (with warnings).

Dependencies

The ssebiEF package automatically manages the following dependencies: - terra for raster manipulation. - dplyr for data manipulation. - stats for statistical calculations.

You do not need to load these packages manually; they are handled internally by ssebiEF

Examples Usage of the ssebiEF Package

To use the ssebiEF package, start by loading the necessary library in R.

• Define the paths to the input files (albedo and TS-TA rasters) and the output path for the calculated SSEBI raster.

  Load the necessary package

  library(ssebEF)

  Input raster paths

  albedo_path <- "path/to/albedo.tif" TS_TA_path <- "path/to/TS_TA.tif"

  Output raster path

  output_path <- "path/to/SSEBI.tif"

  Calculate SSEBI

  calculate_SSEBI( albedo_path = albedo_path, TS_TA_path = TS_TA_path, output_path = output_path, n_intervals = 20, percentile = 0.01 )

  Check the output

  SSEBI <- terra::rast(output_path) plot(SSEBI)

• Define the paths to the input files (albedo and TS-TA rasters) and the output path for the calculated EF raster.

  Load the necessary package

  library(ssebiEF)

  Input raster paths

  albedo_path <- "path/to/albedo.tif" TS_TA_path <- "path/to/TS_TA.tif"

  Output raster path

  output_path <- "path/to/EF.tif"

  Calculate EF

  calculate_EF( albedo_path = albedo_path, TS_TA_path = TS_TA_path, output_path = output_path, n_intervals = 20, percentile = 0.01 )

  Check the output

  EF <- terra::rast(output_path) plot(EF)