| Title: | Calculation of SSEBI and Evaporative Fraction from Raster Data |
|---|---|
| Description: | Calculates a modified Simplified Surface Energy Balance Index (SSEBI) and the Evaporative Fraction (EF) using geospatial raster data such as albedo and surface-air temperature difference (TS–TA). The SSEBI is computed from albedo and TS–TA to estimate surface moisture and evaporative dynamics, providing a robust assessment of surface dryness while accounting for atmospheric variations. Based on Roerink, Su, and Menenti (2000) <doi:10.1016/S1464-1909(99)00128-8>. |
| Authors: | Gaelle Hamelin [aut, cre] (ORCID: <https://orcid.org/0009-0007-2148-7937>) |
| Maintainer: | Gaelle Hamelin <[email protected]> |
| License: | GPL-3 |
| Version: | 1.0.1 |
| Built: | 2026-06-03 09:24:17 UTC |
| Source: | https://github.com/cran/ssebiEF |
This function calculates the EF from two rasters: albedo and the surface-air temperature difference (TS-TA). It saves the resulting EF raster to the specified output path.
calculate_EF( albedo_path, TS_TA_path, output_path, n_intervals = 20, percentile = 0.01 )calculate_EF( albedo_path, TS_TA_path, output_path, n_intervals = 20, percentile = 0.01 )
albedo_path |
Character. File path to the albedo raster.Must have the same CRS and extent as the TS-TA raster. |
TS_TA_path |
Character. File path to the raster of TS-TA (surface-air temperature difference). TS and TA must have the same unit of measurement (Kelvin preferably). |
output_path |
Character. File path where the EF raster will be saved. |
n_intervals |
Integer. Number of intervals for splitting albedo values (default: 20). |
percentile |
Numeric. Percentage used for identifying wet and dry edges (default: 0.01). |
The input rasters (albedo and TS-TA) must have the same CRS (Coordinate Reference System) and extent.
If they differ, the function will attempt to reproject and resample the rasters automatically.
A raster object representing the Evaporative Fraction (EF).
# Paths to example data included in the package library(terra) albedo_raster <- rast(system.file("extdata", "albedo_reduced.tif", package = "ssebiEF")) TS_TA_raster <- rast(system.file("extdata", "TS_TA_reduced.tif", package = "ssebiEF")) # Output path (temporary file for example purposes) output_path <- tempfile(fileext = ".tif") # Run the function calculate_EF( albedo_path = albedo_raster, TS_TA_path = TS_TA_raster, output_path = output_path, n_intervals = 20, percentile = 0.01 ) # Print the output path print(output_path)# Paths to example data included in the package library(terra) albedo_raster <- rast(system.file("extdata", "albedo_reduced.tif", package = "ssebiEF")) TS_TA_raster <- rast(system.file("extdata", "TS_TA_reduced.tif", package = "ssebiEF")) # Output path (temporary file for example purposes) output_path <- tempfile(fileext = ".tif") # Run the function calculate_EF( albedo_path = albedo_raster, TS_TA_path = TS_TA_raster, output_path = output_path, n_intervals = 20, percentile = 0.01 ) # Print the output path print(output_path)
This function calculates the SSEBI from two rasters: albedo and the surface-air temperature difference (TS-TA). It saves the resulting SSEBI raster to the specified output path.
calculate_SSEBI( albedo_path, TS_TA_path, output_path, n_intervals = 20, percentile = 0.01 )calculate_SSEBI( albedo_path, TS_TA_path, output_path, n_intervals = 20, percentile = 0.01 )
albedo_path |
Character. File path to the albedo raster.Must have the same CRS and extent as the TS-TA raster. |
TS_TA_path |
Character. File path to the raster of TS-TA (surface-air temperature difference). TS and TA must have the same unit of measurement (Kelvin preferably). |
output_path |
Character. File path where the SSEBI raster will be saved. |
n_intervals |
Integer. Number of intervals for splitting albedo values (default: 20). |
percentile |
Numeric. Percentage used for identifying wet and dry edges (default: 0.01). |
The input rasters (albedo and TS-TA) must have the same CRS (Coordinate Reference System) and extent.
If they differ, the function will attempt to reproject and resample the rasters automatically.
A raster object representing the Simplified Surface Energy Balance Index (SSEBI).
# Paths to example data included in the package library(terra) albedo_raster <- rast(system.file("extdata", "albedo_reduced.tif", package = "ssebiEF")) TS_TA_raster <- rast(system.file("extdata", "TS_TA_reduced.tif", package = "ssebiEF")) # Output path (temporary file for example purposes) output_path <- tempfile(fileext = ".tif") # Run the function calculate_SSEBI( albedo_path = albedo_raster, TS_TA_path = TS_TA_raster, output_path = output_path, n_intervals = 20, percentile = 0.01 ) # Print the output path print(output_path)# Paths to example data included in the package library(terra) albedo_raster <- rast(system.file("extdata", "albedo_reduced.tif", package = "ssebiEF")) TS_TA_raster <- rast(system.file("extdata", "TS_TA_reduced.tif", package = "ssebiEF")) # Output path (temporary file for example purposes) output_path <- tempfile(fileext = ".tif") # Run the function calculate_SSEBI( albedo_path = albedo_raster, TS_TA_path = TS_TA_raster, output_path = output_path, n_intervals = 20, percentile = 0.01 ) # Print the output path print(output_path)