1i.eb.soilheatflux(1)        GRASS GIS User's Manual       i.eb.soilheatflux(1)
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NAME

6       i.eb.soilheatflux  - Soil heat flux approximation (Bastiaanssen, 1995).
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KEYWORDS

9       imagery, energy balance, soil heat flux, SEBAL
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SYNOPSIS

12       i.eb.soilheatflux
13       i.eb.soilheatflux --help
14       i.eb.soilheatflux [-r] albedo=name ndvi=name temperature=name netradia‐
15       tion=name  localutctime=name   output=name    [--overwrite]    [--help]
16       [--verbose]  [--quiet]  [--ui]
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18   Flags:
19       -r
20           HAPEX-Sahel empirical correction (Roerink, 1995)
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22       --overwrite
23           Allow output files to overwrite existing files
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25       --help
26           Print usage summary
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28       --verbose
29           Verbose module output
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31       --quiet
32           Quiet module output
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34       --ui
35           Force launching GUI dialog
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37   Parameters:
38       albedo=name [required]
39           Name of albedo raster map [0.0;1.0]
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41       ndvi=name [required]
42           Name of NDVI raster map [-1.0;+1.0]
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44       temperature=name [required]
45           Name of Surface temperature raster map [K]
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47       netradiation=name [required]
48           Name of Net Radiation raster map [W/m2]
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50       localutctime=name [required]
51           Name of time of satellite overpass raster map [local time in UTC]
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53       output=name [required]
54           Name for output raster map
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DESCRIPTION

57       i.eb.soilheatflux  calculates  the  soil  heat  flux approximation (g0)
58       after Bastiaanssen (1995). The main  reference  for  implementation  is
59       Alexandridis,  2009.  It takes input of Albedo, NDVI, Surface Skin tem‐
60       perature, Net Radiation (see r.sun), time of satellite overpass, and  a
61       flag for the Roerink empirical modification from the HAPEX-Sahel exper‐
62       iment.  The "time of satellite overpass" map can be  obtained  as  fol‐
63       lows:
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65           ·   MODIS:  a related sub dataset is included in each HDF file, and
66               simply to be imported as a raster map;
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68           ·   Landsat: to be generated as map from the overpass  time  stored
69               in  the metadata file (given in Greenwich Mean Time - GMT), see
70               below.
71       For Landsat, the overpass map can  be  computed  by  using  a  two-step
72       method:
73       # 1) extract the overpass time in GMT from metadata file
74       i.landsat.toar -p input=dummy output=dummy2 \
75          metfile=LC81250452013338LGN00_MTL.txt lsatmet=time
76       # ... in this example approx. 03:12am GMT
77       # 2) create map for computational region of Landsat scene
78       g.region rast=LC81250452013338LGN00_B4 -p
79       r.mapcalc "overpasstime = 3.211328"
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SEE ALSO

82         r.sun,  i.albedo,  i.emissivity,  i.eb.hsebal01,  i.eb.evapfr i.land‐
83       sat.toar
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REFERENCES

86       Bastiaanssen, W.G.M., 1995.  Estimation of Land surface  parameters  by
87       remote  sensing under clear-sky conditions. PhD thesis, Wageningen Uni‐
88       versity, Wageningen, The Netherlands.  (PDF)
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90       Chemin Y., Alexandridis T.A., 2001. Improving spatial resolution of  ET
91       seasonal  for irrigated rice in Zhanghe, China. Asian Journal of Geoin‐
92       formatics. 5(1):3-11,2004.
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94       Alexandridis T.K., Cherif I., Chemin Y., Silleos  N.G.,  Stavrinos  E.,
95       Zalidis  G.C.  Integrated  methodology  for  estimating  water  use  in
96       Mediterranean agricultural areas. Remote  Sensing.  2009,  1,  445-465.
97       (PDF)
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99       Chemin,  Y.,  2012.  A Distributed Benchmarking Framework for Actual ET
100       Models, in: Irmak, A. (Ed.), Evapotranspiration -  Remote  Sensing  and
101       Modeling. InTech.  (PDF)
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AUTHOR

104       Yann Chemin, Asian Institute of Technology, Thailand
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SOURCE CODE

107       Available at: i.eb.soilheatflux source code (history)
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109       Main  index | Imagery index | Topics index | Keywords index | Graphical
110       index | Full index
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112       © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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116GRASS 7.8.5                                               i.eb.soilheatflux(1)
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