---
name: "i.eb.eta"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "8.4.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/i.eb.eta"
---

# i.eb.eta(1grass)

Actual evapotranspiration for diurnal period (Bastiaanssen, 1995).

## 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**

  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:

- **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 \[mm/d\]

## DESCRIPTION

*i.eb.eta* calculates the actual evapotranspiration (ETa ; mm/d) for 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.

## NOTES

Full ETa processing will need those:

- •

  *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 \[1\]\[2\]\[3\]\[4\].

## 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: Monday Feb 24 17:51:32 2025

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