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i.eb.hsebal01

Computes sensible heat flux iteration SEBAL 01.

i.eb.hsebal01 [-ac] netradiation=name soilheatflux=name aerodynresistance=name temperaturemeansealevel=name vapourpressureactual=name frictionvelocitystar=float [row_wet_pixel=float] [column_wet_pixel=float] [row_dry_pixel=float] [column_dry_pixel=float] output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

i.eb.hsebal01 netradiation=name soilheatflux=name aerodynresistance=name temperaturemeansealevel=name vapourpressureactual=name frictionvelocitystar=0.32407 output=name

grass.script.run_command("i.eb.hsebal01", netradiation, soilheatflux, aerodynresistance, temperaturemeansealevel, vapourpressureactual, frictionvelocitystar=0.32407, row_wet_pixel=None, column_wet_pixel=None, row_dry_pixel=None, column_dry_pixel=None, output, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("i.eb.hsebal01", netradiation="name", soilheatflux="name", aerodynresistance="name", temperaturemeansealevel="name", vapourpressureactual="name", frictionvelocitystar=0.32407, output="name")

Parameters

netradiation=name [required]
    Name of instantaneous net radiation raster map [W/m2]
soilheatflux=name [required]
    Name of instantaneous soil heat flux raster map [W/m2]
aerodynresistance=name [required]
    Name of aerodynamic resistance to heat momentum raster map [s/m]
temperaturemeansealevel=name [required]
    Name of altitude corrected surface temperature raster map [K]
vapourpressureactual=name [required]
    Name of the actual vapour pressure (e_act) map [KPa]
frictionvelocitystar=float [required]
    Value of the height independent friction velocity (u*) [m/s]
    Default: 0.32407
row_wet_pixel=float
    Row value of the wet pixel
column_wet_pixel=float
    Column value of the wet pixel
row_dry_pixel=float
    Row value of the dry pixel
column_dry_pixel=float
    Column value of the dry pixel
output=name [required]
    Name for output sensible heat flux raster map [W/m2]
-a
    Automatic wet/dry pixel (careful!)
-c
    Dry/Wet pixels coordinates are in image projection, not row/col
--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

netradiation : str, required
    Name of instantaneous net radiation raster map [W/m2]
    Used as: input, raster, name
soilheatflux : str, required
    Name of instantaneous soil heat flux raster map [W/m2]
    Used as: input, raster, name
aerodynresistance : str, required
    Name of aerodynamic resistance to heat momentum raster map [s/m]
    Used as: input, raster, name
temperaturemeansealevel : str, required
    Name of altitude corrected surface temperature raster map [K]
    Used as: input, raster, name
vapourpressureactual : str, required
    Name of the actual vapour pressure (e_act) map [KPa]
    Used as: input, raster, name
frictionvelocitystar : float, required
    Value of the height independent friction velocity (u*) [m/s]
    Default: 0.32407
row_wet_pixel : float, optional
    Row value of the wet pixel
column_wet_pixel : float, optional
    Column value of the wet pixel
row_dry_pixel : float, optional
    Row value of the dry pixel
column_dry_pixel : float, optional
    Column value of the dry pixel
output : str, required
    Name for output sensible heat flux raster map [W/m2]
    Used as: output, raster, name
flags : str, optional
    Allowed values: a, c
    a
        Automatic wet/dry pixel (careful!)
    c
        Dry/Wet pixels coordinates are in image projection, not row/col
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.eb.hsebal01 will calculate the sensible heat flux map (h0), given both maps of Net Radiation and soil Heat flux (Rn, g0) at instantaneous time, the surface roughness (z0m), a map of the altitude corrected temperature (t0dem), a point data of the frictional velocity (u*), a value of actual vapour pressure (ea[KPa]) and the (x,y) pairs for wet and dry pixels. Full process 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)

i.eb.hsebal01 performs the computation of sensible heat flux [W/m2] after Bastiaanssen, 1995 in [1], used in this form in 2001 by [2]. Implemented in this code in [3].

NOTES

  • z0m can be alculated by i.eb.z0m or i.eb.z0m0 (GRASS Addons).
  • ea can be calculated with standard meteorological data.
    eoTmin=0.6108*EXP(17.27*Tmin/(Tmin+237.3))
    eoTmax=0.6108*EXP(17.27*Tmax/(Tmax+237.3))
    ea=(RH/100)/((eoTmin+eoTmax)/2)
  • t0dem = surface temperature + (altitude * 0.627 / 100)

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

i.eb.soilheatflux, i.eb.evapfr

AUTHOR

Yann Chemin, International Rice Research Institute, Los Banos, The Philippines.

Contact: Yann Chemin

SOURCE CODE

Available at: i.eb.hsebal01 source code (history)
Latest change: Wednesday Apr 02 17:48:37 2025 in commit 571253a