i.eb.hsebal01grass - Online in the Cloud

PROGRAM:

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 frictionvelocitystar=float vapourpressureactual=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]

frictionvelocitystar=float [required]
Value of the height independent friction velocity (u*) [m/s]
Default: 0.32407

vapourpressureactual=float [required]
Value of the actual vapour pressure (e_act) [KPa]
Default: 1.511

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]

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)

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