i.eb.soilheatflux(1grass)

🎀 i.eb.soilheatflux — the manual page, bestie edition 🎀

okay so real talk, this is i.eb.soilheatflux from the 1grass GRASS User's Manual. It does soil heat flux stuff. Let's get into it. 💖

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✨ NAME ✨

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

Like, that's the whole name section. Short, sweet, iconic. Periodt. 💅

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🦋 KEYWORDS 🦋

imagery, energy balance, soil heat flux, SEBAL

(yes bestie, those are the tags, iykyk 🌸)

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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 — the HAPEX-Sahel empirical correction (Roerink, 1995). yes it's a real thing, no you cannot skip it if you need it.
• --overwrite — let your output files just, like, bulldoze whatever was already there. allow output files to overwrite existing files ✨
• --help — print usage summary. the "help me bestie" button 🫶
• --verbose — verbose module output. it will literally tell you everything.
• --quiet — quiet module output. shhh. 🤫
• --ui — force launching GUI dialog. for when you want buttons instead of typing 💅

🌸 Parameters 🌸

• albedo=name [required] — Name of albedo raster map, and it lives in the range [0.0;1.0].
• ndvi=name [required] — Name of NDVI raster map, range [-1.0;+1.0].
• temperature=name [required] — Name of Surface temperature raster map, in [K] (kelvin, obviously 👑).
• netradiation=name [required] — Name of Net Radiation raster map, in [W/m2].
• localutctime=name [required] — Name of time of satellite overpass raster map, in [local time in UTC].
• output=name [required] — Name for output raster map. this is the one you get to name yourself, main character energy 💖

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💜 DESCRIPTION 💜

i.eb.soilheatflux calculates the soil heat flux approximation (g0) after Bastiaanssen (1995). The main reference for implementation is Alexandridis, 2009.

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.

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"

like, the whole pipeline is right there, slay 🔥

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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)

(go read them, bestie, they're the receipts 📖✨)

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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

(we stan 🌟)

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💻 SOURCE CODE 💻

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

Latest change: Tuesday Jun 24 19:50:46 2025 in commit: 48219eb35dc74b741d553152a17f70b0070e37e1

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

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okay that's the whole thinggg 💖 This was i.eb.soilheatflux from the GRASS 8.5.0 Reference Manual, © 2003-2026 GRASS Development Team — like literally the whole squad has been at this since 2003, no cap. Byeee bestie, go compute some soil heat flux! 🦋🌸💅