GRASS GIS manual: i.eb.deltat

NAME

i.eb.deltat - Computes the difference of temperature between surface skin temperature and air temperature at 2m as part of sensible heat flux calculations.

KEYWORDS

imagery, energy balance, SEBAL, SEBS, delta T

SYNOPSIS

i.eb.deltat

i.eb.deltat --help

i.eb.deltat [-w] tempk=name delta=name [--help] [--verbose] [--quiet] [--ui]

Flags:

-w: Wim's generic table
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

tempk=name [required]: Name of the surface skin temperature map [Kelvin]; Default: tempk
delta=name [required]: Name of the output delta layer; Default: delta

DESCRIPTION
NOTES
TODO
SEE ALSO
AUTHORS

DESCRIPTION

i.eb.deltat calculates the difference of temperature between two heights. Generally considered between surface skin temperature and air temperature ~2m above the skin (soil/canopy/etc). This approximation is found in Pawan (2004) and is used for initialization of the sensible heat flux iterations in SEBAL (Bastiaanssen, 1995).

NOTES

This is found in Pawan (2004). This is the case of a Landsat satellite image of Oct 8, 2003, located in Portugal. He also mentions a strange equation for MODIS of January 13, 2003. delta T = -3440.37 +12.18404 * LST. Of course the intercept looks like the LST band is still in storage format (*10000). Additionally, it is worth menitoning that Pawan only created this map once, and used it all the time. This is certainly because he created the relationship from some field data and found it reliable enough not to modify this parameter anymore, leading to a simplified iteration process of SEBAL, changing only the rah parameter through the iterations of H,L,psi,rah.