i.evapo.zk

Computes global evapotranspiration calculation after Zhang, Kimball, Nemani and Running formulation, 2010.

Command linePython (grass.script)

i.evapo.zk biome_type=name ndvi=name airtemperature=name specifichumidity=name atmosphericpressure=name netradiation=name soilheatflux=name elevation=name output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

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

grass.script.run_command("i.evapo.zk", biome_type, ndvi, airtemperature, specifichumidity, atmosphericpressure, netradiation, soilheatflux, elevation, output, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("i.evapo.zk", biome_type="name", ndvi="name", airtemperature="name", specifichumidity="name", atmosphericpressure="name", netradiation="name", soilheatflux="name", elevation="name", output="name")

Parameters

Command linePython (grass.script)

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]
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

biome_type : str, required
    Name of input IGBP biome type raster map [-]
    Used as: input, raster, name
ndvi : str, required
    Name of input Normalized Difference Vegetation Index raster map [-]
    Used as: input, raster, name
airtemperature : str, required
    Name of input air temperature raster map [C]
    Used as: input, raster, name
specifichumidity : str, required
    Name of input specific humidity raster map [-]
    Used as: input, raster, name
atmosphericpressure : str, required
    Name of input atmospheric pressure raster map [Pa]
    Used as: input, raster, name
netradiation : str, required
    Name of input net radiation raster map [MJ/m2/d]
    Used as: input, raster, name
soilheatflux : str, required
    Name of input soil heat flux raster map [MJ/m2/d]
    Used as: input, raster, name
elevation : str, required
    Name of input elevation raster map [m]
    Used as: input, raster, name
output : str, required
    Name of output evapotranspiration raster map [mm/d]
    Used as: output, raster, name
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

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"

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, DOI: 10.5772/23571)

AUTHOR

Yann Chemin, GRASS Development Team, 2011

SOURCE CODE

Available at: i.evapo.zk source code (history)
Latest change: Friday Feb 21 10:10:05 2025 in commit 7d78fe3