1i.eb.netrad(1)              GRASS GIS User's Manual             i.eb.netrad(1)
2
3
4

NAME

6       i.eb.netrad  - Net radiation approximation (Bastiaanssen, 1995).
7

KEYWORDS

9       imagery, energy balance, net radiation, SEBAL
10

SYNOPSIS

12       i.eb.netrad
13       i.eb.netrad --help
14       i.eb.netrad  albedo=name  ndvi=name  temperature=name localutctime=name
15       temperaturedifference2m=name   emissivity=name   transmissivity_single‐
16       way=name  dayofyear=name sunzenithangle=name output=name  [--overwrite]
17       [--help]  [--verbose]  [--quiet]  [--ui]
18
19   Flags:
20       --overwrite
21           Allow output files to overwrite existing files
22
23       --help
24           Print usage summary
25
26       --verbose
27           Verbose module output
28
29       --quiet
30           Quiet module output
31
32       --ui
33           Force launching GUI dialog
34
35   Parameters:
36       albedo=name [required]
37           Name of albedo raster map [0.0;1.0]
38
39       ndvi=name [required]
40           Name of NDVI raster map [-1.0;+1.0]
41
42       temperature=name [required]
43           Name of surface temperature raster map [K]
44
45       localutctime=name [required]
46           Name of time of satellite overpass raster map [local time in UTC]
47
48       temperaturedifference2m=name [required]
49           Name of the difference map of  temperature  from  surface  skin  to
50           about 2 m height [K]
51
52       emissivity=name [required]
53           Name of the emissivity map [-]
54
55       transmissivity_singleway=name [required]
56           Name of the single-way atmospheric transmissivitymap [-]
57
58       dayofyear=name [required]
59           Name of the Day Of Year (DOY) map [-]
60
61       sunzenithangle=name [required]
62           Name of the sun zenith angle map [degrees]
63
64       output=name [required]
65           Name of the output net radiation layer
66

DESCRIPTION

68       i.eb.netrad calculates the net radiation at the time of satellite over‐
69       pass, the way it is in the SEBAL  model  of  Bastiaanssen  (1995).   It
70       takes  input  of Albedo, NDVI, Surface Skin temperature, time of satel‐
71       lite overpass, surface emissivity, difference of temperature from  sur‐
72       face  skin  and about 2 m height (dT), instantaneous satellite overpass
73       single-way atmospheric transmissivity (tsw), Day of Year (DOY), and sun
74       zenith angle.
75

NOTES

77       In  the old methods, dT was taken as flat images (dT=5.0), if you don’t
78       have a dT map from ground data, you would want to try something in this
79       line,  this  is  to calculate atmospherical energy balance. In the same
80       way, a standard tsw is used in those equations. Refer  to  r_net.c  for
81       that  and for other non-used equations, but stored in there for further
82       research convenience.
83

TODO

85       Add more explanations.
86

REFERENCES

88           •   Bastiaanssen, W.G.M., 1995.  Regionalization  of  surface  flux
89               densities  and  moisture indicators in composite terrain; a re‐
90               mote sensing approach under clear skies in  mediterranean  cli‐
91               mates.  PhD  thesis, Wageningen Agricultural Univ., The Nether‐
92               land, 271 pp.  (PDF)
93
94           •   Chemin, Y., 2012.  A Distributed Benchmarking Framework for Ac‐
95               tual  ET  Models, in: Irmak, A. (Ed.), Evapotranspiration - Re‐
96               mote Sensing and Modeling. InTech.  (PDF)
97

SEE ALSO

99        i.eb.soilheatflux, i.eb.hsebal01, i.albedo
100

AUTHOR

102       Yann Chemin, International Rice Research Institute, The Philippines
103

SOURCE CODE

105       Available at: i.eb.netrad source code (history)
106
107       Accessed: Saturday Jan 21 21:16:36 2023
108
109       Main index | Imagery index | Topics index | Keywords index |  Graphical
110       index | Full index
111
112       © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
113
114
115
116GRASS 8.2.1                                                     i.eb.netrad(1)