i.eb.eta(1grass)

💅 i.eb.eta — actual evapotranspiration for the diurnal period 💅

okay bestie, welcome to i.eb.eta(1grass), a GRASS GIS module that does Actual evapotranspiration for diurnal period (Bastiaanssen, 1995). yes that's the whole NAME. short, iconic, to the point. periodt.

🏷️ KEYWORDS

imagery, energy balance, actual evapotranspiration, SEBAL

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✨ 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 — bestie it will let the output files overwrite files that already exist. use with intention, not on vibes.
• --help — prints the usage summary, aka the "what do I even type" menu.
• --verbose — verbose module output. she talks more. we love that for her.
• --quiet — quiet module output. she says nothing and just works. also iconic.
• --ui — force launches the GUI dialog, for when you want the little clicky boxes instead of the terminal.

🌸 Parameters

• netradiationdiurnal=name [required] — name of the diurnal net radiation map [W/m2]. default: rnetday
• evaporativefraction=name [required] — name of the evaporative fraction map [-]. default: evapfr
• temperature=name [required] — name of the surface skin temperature [K]. default: tempk
• output=name [required] — name of the output actual evapotranspiration layer [mm/d]. no default, you gotta name your baby yourself ✨

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📖 DESCRIPTION

i.eb.eta calculates the actual evapotranspiration (ETa; mm/d) for the diurnal period after [1], implemented in [3]. it takes input of Diurnal Net Radiation (see r.sun), evaporative fraction (see i.eb.evapfr) and surface skin temperature.

that's it. that's the whole job. she takes three maps and hands you back ETa. no cap. 🦋

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📝 NOTES

a Full ETa processing will need all of these, so like, do not skip:

• 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]. iykyk 💜

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📚 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)

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👀 SEE ALSO

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

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👑 AUTHOR

Yann Chemin, Asian Institute of Technology, Thailand

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💻 SOURCE CODE

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

Latest change: Thursday Jun 26 21:25:27 2025 in commit: 3ec2b13945d963db69544e3fc9339fbff72f33f3

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

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okay that's the whole page bestie, you're officially fluent in i.eb.eta now 🫶

and a lil cute sign-off because she deserves it: this is from the GRASS 8.5.0 Reference Manual, © 2003-2026 GRASS Development Team, and the version stamped on this whole thing is GRASS 8.5.0 💖 go evaporate some water, slay 💅🌈💀