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.
NAME
i.eb.hsebal01  - Computes sensible heat flux iteration SEBAL 01.
KEYWORDS
imagery, 
energy balance, 
soil moisture, 
evaporative fraction, 
SEBAL
SYNOPSIS
i.eb.hsebal01
i.eb.hsebal01 --help
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]  [--help]  [--verbose]  [--quiet]  [--ui] 
Flags:
- -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
 
- --ui
 
- Force launching GUI dialog
 
 
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]
 
 
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].
-  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)
 
[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)
i.eb.soilheatflux,
i.eb.evapfr
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 Feb 09 22:41:37 2022 in commit: c37871b51d202b155b64ba04288c4242826936f2
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.
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GRASS GIS 8.2.2dev Reference Manual