i.eb.evapfr(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 i.eb.evapfr — GRASS GIS User's Manual 💖

okay bestie, sit down, hydrate, because we're about to compute evaporative fraction and root zone soil moisture and it's literally gonna slay. this is a page from the GRASS GIS User's Manual, module i.eb.evapfr(1), and yes it's giving ✨remote sensing energy balance✨.

🌸 NAME 🌸

i.eb.evapfr — computes evaporative fraction and root zone soil moisture. that's it, that's the whole job, and she does it beautifully 💅

🎀 KEYWORDS 🎀

imagery, energy balance, soil moisture, evaporative fraction, SEBAL

iykyk 🦋

✨ SYNOPSIS ✨

i.eb.evapfr
i.eb.evapfr --help
i.eb.evapfr [-m] netradiation=name soilheatflux=name
sensibleheatflux=name evaporativefraction=name  [soilmoisture=name]
[--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🚩 Flags 🚩

  • -m — turns on the root zone soil moisture output (Makin, Molden and Bastiaanssen, 2001). the main character flag, honestly 👑
  • --overwrite — lets output files overwrite files that already exist. chaotic but permitted 😌
  • --help — prints the usage summary. when u just need a lil recap 🫶
  • --verbose — verbose module output. she talks more.
  • --quiet — quiet module output. she talks less 🤫
  • --ui — forces the GUI dialog to launch. clicky clicky ✨

🌈 Parameters 🌈

  • netradiation=name [required] — name of the Net Radiation raster map, in [W/m2]. required, bestie, no skipping 🔥
  • soilheatflux=name [required] — name of the soil heat flux raster map, in [W/m2]. also required 💀
  • sensibleheatflux=name [required] — name of the sensible heat flux raster map, in [W/m2]. required required required 🎀
  • evaporativefraction=name [required] — name for the output evaporative fraction raster map. this is the moment ✨
  • soilmoisture=name — name for the output root zone soil moisture raster map. optional, but she's iconic when she shows up 💜

💅 DESCRIPTION 💅

okay so i.eb.evapfr calculates the evaporative fraction after Bastiaanssen 1995. the main implementation follows Alexandridis et al. (2009) — like, that's the blueprint, that's the vibe 🌸

the module takes as input:

  • the net radiation (peep r.sun, i.eb.netrad)
  • soil heat flux (peep i.eb.soilheatflux)
  • and sensible heat flux (peep i.eb.hsebal01)

a flag adds a root zone empirical soil moisture output, straight from the article of Bastiaanssen, et al. (2000). the way that one flag just unlocks a whole extra output… obsessed 😭

📚 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)
  • Bastiaanssen, W.G.M., Molden, D.J., Makin, I.W., 2000. Remote sensing for irrigated agriculture: examples from research and possible applications. Agricultural water management 46.2: 137-155.
  • 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.
  • Alexandridis T.K., Cherif I., Chemin Y., Silleos N.G., Stavrinos E., Zalidis G.C., 2009. Integrated methodology for estimating water use in Mediterranean agricultural areas. Remote Sensing. 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)

like, the receipts are RIGHT THERE. cite ur sources, queens 📖👑

👀 SEE ALSO 👀

i.eb.hsebal01, i.eb.netrad, i.eb.soilheatflux, r.sun

go read those next, bestie, they're the whole friend group 🫶

🧚 AUTHOR 🧚

Yann Chemin, Asian Institute of Technology, Thailand

thank u for ur service 🫡✨

💻 SOURCE CODE 💻

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

Accessed: Saturday Jan 17 05:41:38 2026

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and that's the whole page, bestie 💖 this was GRASS GIS 8.4.2, © 2003-2025 GRASS Development Team, from the GRASS GIS 8.4.2 Reference Manual — accessed Saturday Jan 17 05:41:38 2026. now go compute some evaporative fraction and be the main character of ur watershed 🌈⭐ periodt 💅

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