i.eb.soilheatflux(1)

✨ i.eb.soilheatflux ✨

okay bestie, welcome to the GRASS GIS User's Manual page for i.eb.soilheatflux(1) 🫶 — yes that's the module name, yes it's a mouthful, we're gonna get through it together 💅

🌸 NAME 🌸

i.eb.soilheatflux — Soil heat flux approximation (Bastiaanssen, 1995).

🎀 KEYWORDS 🎀

imagery, energy balance, soil heat flux, SEBAL

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🦋 SYNOPSIS 🦋

i.eb.soilheatflux
i.eb.soilheatflux --help
i.eb.soilheatflux [-r] albedo=name ndvi=name temperature=name
netradiation=name localutctime=name output=name  [--overwrite]  [--help]
[--verbose]  [--quiet]  [--ui]

💖 Flags 💖

• -r — HAPEX-Sahel empirical correction (Roerink, 1995) ✨
• --overwrite — Allow output files to overwrite existing files
• --help — Print usage summary
• --verbose — Verbose module output
• --quiet — Quiet module output
• --ui — Force launching GUI dialog

💜 Parameters 💜

• albedo=name [required] — Name of albedo raster map [0.0;1.0]
• ndvi=name [required] — Name of NDVI raster map [-1.0;+1.0]
• temperature=name [required] — Name of Surface temperature raster map [K]
• netradiation=name [required] — Name of Net Radiation raster map [W/m2]
• localutctime=name [required] — Name of time of satellite overpass raster map [local time in UTC]
• output=name [required] — Name for output raster map

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🌈 DESCRIPTION 🌈

so i.eb.soilheatflux calculates the soil heat flux approximation (g0) after Bastiaanssen (1995) 🔥. The main reference for implementation is Alexandridis, 2009 — noted, respected, iconic 📚.

It takes input of Albedo, NDVI, Surface Skin temperature, Net Radiation (see r.sun), time of satellite overpass, and a flag for the Roerink empirical modification from the HAPEX-Sahel experiment. no cap, that's the whole roster 💫

The "time of satellite overpass" map can be obtained as follows:

• MODIS: a related sub dataset is included in each HDF file, and simply to be imported as a raster map;
• Landsat: to be generated as map from the overpass time stored in the metadata file (given in Greenwich Mean Time - GMT), see below.

For Landsat, the overpass map can be computed by using a two-step method:

# 1) extract the overpass time in GMT from metadata file
i.landsat.toar -p input=dummy output=dummy2 \
   metfile=LC81250452013338LGN00_MTL.txt lsatmet=time
# ... in this example approx. 03:12am GMT
# 2) create map for computational region of Landsat scene
g.region rast=LC81250452013338LGN00_B4 -p
r.mapcalc "overpasstime = 3.211328"

fr fr, copy those commands exactly, they're doing the Lord's work 🙏

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👑 REFERENCES 👑

Bastiaanssen, W.G.M., 1995. Estimation of Land surface parameters by remote sensing under clear-sky conditions. PhD thesis, Wageningen University, Wageningen, The Netherlands. (PDF)

Chemin Y., Alexandridis T.A., 2001. Improving spatial resolution of ET seasonal for irrigated rice in Zhanghe, China. Asian Journal of Geoinformatics. 5(1):3-11,2004.

Alexandridis T.K., Cherif I., Chemin Y., Silleos N.G., Stavrinos E., Zalidis G.C. Integrated methodology for estimating water use in Mediterranean agricultural areas. Remote Sensing. 2009, 1, 445-465. (PDF)

Chemin, Y., 2012. A Distributed Benchmarking Framework for Actual ET Models, in: Irmak, A. (Ed.), Evapotranspiration - Remote Sensing and Modeling. InTech. (PDF)

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⭐ SEE ALSO ⭐

r.sun, i.albedo, i.emissivity, i.eb.hsebal01, i.eb.evapfr, i.landsat.toar

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🍓 AUTHOR 🍓

Yann Chemin, Asian Institute of Technology, Thailand

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💀 SOURCE CODE 💀

Available at: i.eb.soilheatflux source code (history)

Accessed: Saturday Jan 17 05:41:39 2026

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and that's the whole page bestie, you ate it 💅✨ this was GRASS GIS 8.4.2 Reference Manual energy, © 2003-2025 GRASS Development Team, and the footer vibe is GRASS 8.4.2, i.eb.soilheatflux(1) — periodt 🫶🌸