i.evapo.zk - GRASS GIS manual

Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.

Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.

NAME

i.evapo.zk - Computes global evapotranspiration calculation after Zhang, Kimball, Nemani and Running formulation, 2010.

KEYWORDS

imagery, evapotranspiration

SYNOPSIS

i.evapo.zk

i.evapo.zk --help

i.evapo.zk biome_type=name ndvi=name airtemperature=name specifichumidity=name atmosphericpressure=name netradiation=name soilheatflux=name elevation=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:

biome_type=name [required]: Name of input IGBP biome type raster map [-]
ndvi=name [required]: Name of input Normalized Difference Vegetation Index raster map [-]
airtemperature=name [required]: Name of input air temperature raster map [C]
specifichumidity=name [required]: Name of input specific humidity raster map [-]
atmosphericpressure=name [required]: Name of input atmospheric pressure raster map [Pa]
netradiation=name [required]: Name of input net radiation raster map [MJ/m2/d]
soilheatflux=name [required]: Name of input soil heat flux raster map [MJ/m2/d]
elevation=name [required]: Name of input elevation raster map [m]
output=name [required]: Name of output evapotranspiration raster map [mm/d]

DESCRIPTION
NOTES
TODO
SEE ALSO
REFERENCES
AUTHOR

DESCRIPTION

i.evapo.zk Calculates the global diurnal evapotranspiration after Zhang, Kimball, Nemani and Running (2010).

NOTES

Main function ETa (biome_type, ndvi, tday, sh, patm, Rn, G)

Biome_type as defined below
ndvi NDVI value [-]
tday day temperature [C]
sh specific humidity [-]
patm atmospheric pressure [Pa]
Rn day net radiation [MJ/m2/d]
G day soil heat flux [MJ/m2/d]

IGBP Biome types with ID used in this model

Code ID Description
BENF 0 Boreal Evergreen Needleleaf Forest (less or eq 212 frost-free days)
TENF 1 Temperate Evergreen Needleleaf Forest (more than 212 frost-free days)
EBF 2 Evergreen Broadleaf Forest
DBF 4 Deciduous Broadleaf Forest
CSH 6 Closed Shrubland
OSH 7 Open Shrubland
WSV 8 Woody Savannah
SV 9 Savannah
GRS 10 Grassland
CRP 12 Cropland

IGBP Classification

01 Evergreen Needleleaf Forest
02 Evergreen Broadleaf Forest
03* Deciduous Needleleaf Forest
04 Deciduous Broadleaf Forest
05* Mixed Forest (stats of other classes areas used in article)
06 Closed Shrublands
07 Open Shrublands
08 Woody Savannas
09 Savannas
10 Grasslands
11* Permanent Wetlands
12 Croplands
13* Urban and Built-Up
14* Cropland/Natural Vegetation Mosaic
15* Snow and Ice
16* Barren or Sparsely Vegetated
17* Water Bodies (Evaporation Priestley-Taylor used in article)

* Not used in this model IGBP Biome types and configuration of internal parameters of the model

Code Description TcloseMinC TopenMaxC VPDClosePa VPDOpenPa ToptC BetaC kPa GaMs-1 GtotMs-1 GchMs-1 B1Sm-1 B2Sm-1 B3 b1* b2* b3* b4*
BENF Boreal Evergreen Needleleaf Forest -8 40 2800 500 12 25 150 0.03 0.002 0.08 208.3 8333.3 10
TENF Temperate Evergreen Needleleaf Forest -8 40 2800 500 25 25 200 0.03 0.004 0.08 133.3 888.9 6
EBF Evergreen Broadleaf Forest -8 50 4000 500 40 40 300 0.03 0.006 0.01 57.7 769.2 4.5
DBF Deciduous Broadleaf Forest -6 45 2800 650 28 25 200 0.04 0.002 0.01 85.8 694.7 4
MF Mixed Forest
CSH Closed Shrubland -8 45 3300 500 19 20 400 0.01 0.001 0.04 202 4040.4 6.5
OSH Open Shrubland -8 40 3700 500 10 30 50 0.005 0.012 0.04 178.6 178.6 8
WSV Woody Savannah -8 50 3200 500 32 28 900 0.002 0.0018 0.04 0.2 24000 6.5 57.1* 3333.3* 8* -0.01035*
SV Savannah -8 40 5000 650 32 30 800 0.001 0.001 0.04 790.9 8181.8 10
GRS Grassland -8 40 3800 650 20 30 500 0.001 0.001 0.04 175 2000 6
CRP Cropland -8 45 3800 650 20 30 450 0.005 0.003 0.04 105 3000 3

* For WSV when NDVI superior to 0.64"

TODO

REFERENCES

Zhang, K., Kimball, J.S., Nemani, R.R., Running, S.W. (2010). A continuous satellite-derived global record of land surface evapotranspiration from 1983 to 2006. WRR 46, W09522

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

AUTHOR

Yann Chemin, GRASS Development team, 2011

SOURCE CODE

Available at: i.evapo.zk source code (history)

Latest change: Monday Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55