i.eb.eta(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 i.eb.eta — the GRASS GIS User's Manual glow-up 💖

okay bestie, welcome to i.eb.eta(1) — yes that's the manual name, it's giving imagery module, energy balance, actual evapotranspiration, SEBAL, and honestly? we're obsessed.

✨ NAME ✨

i.eb.eta — Actual evapotranspiration for diurnal period (Bastiaanssen, 1995).

🏷️ KEYWORDS 🏷️

imagery, energy balance, actual evapotranspiration, SEBAL

🦋 SYNOPSIS 🦋

i.eb.eta
i.eb.eta --help
i.eb.eta netradiationdiurnal=name evaporativefraction=name
temperature=name output=name  [--overwrite]  [--help]  [--verbose]
[--quiet]  [--ui]

🎀 Flags 🎀

  • --overwrite — let your output files just yeet whatever was there before. overwrite existing files, permission granted 💅
  • --help — prints the usage summary, for when you need a lil recap
  • --verbose — verbose module output, the module will NOT stop yapping (affectionate)
  • --quiet — quiet module output, shhh era 🤫
  • --ui — force launches the GUI dialog, for the visual girlies

🍓 Parameters 🍓

  • netradiationdiurnal=name [required] — name of the diurnal net radiation map, in [W/m2]. Default: rnetday
  • evaporativefraction=name [required] — name of the evaporative fraction map, in [-]. Default: evapfr
  • temperature=name [required] — name of the surface skin temperature, in [K]. Default: tempk
  • output=name [required] — name of the output actual evapotranspiration layer, in [mm/d]

🌸 DESCRIPTION 🌸

so i.eb.eta calculates the actual evapotranspiration (ETa; mm/d) for the diurnal period, following [1], implemented in [3]. it's literally taking three things as input:

  • Diurnal Net Radiation — go check r.sun for that one
  • evaporative fraction — that's i.eb.evapfr's whole thing
  • surface skin temperature

put them together and you get your ETa. main character energy fr fr 👑

👑 NOTES 👑

full ETa processing is gonna need all of these, no cap:

  • i.vi, i.albedo, r.latlong, i.emissivity
  • i.evapo.potrad (GRASS Addon)
  • i.eb.netrad, i.eb.soilheatflux, i.eb.hsebal01
  • i.eb.evapfr, i.eb.eta

(for time integration: i.evapo.time_integration)

for more details on the algorithms, see [1][2][3][4]. that's your reading list bestie, go off 📚

📚 REFERENCES 📚

[1] 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)

[2] 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.

[3] 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)

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

💜 SEE ALSO 💜

r.sun, i.eb.evapfr, i.eb.netrad

🫶 AUTHOR 🫶

Yann Chemin, Asian Institute of Technology, Thailand

🌈 SOURCE CODE 🌈

available at: i.eb.eta source code (history)

accessed: Saturday Jan 17 05:41:38 2026

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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual

and that's the whole page bestie — brought to you by GRASS 8.4.2, the i.eb.eta(1) manual, last peeked at on Saturday Jan 17 05:41:38 2026. slay, hydrate, and go compute some evapotranspiration 💖✨🎀
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