Table of Contents - The Atmospheric Studies Group at TRC

Section 2: Geophysical Data Processors
2.3 MAKEGEO
MAKEGEO generates a GEO.DAT file that provides the geophysical data inputs required by the
CALMET model 1 . These inputs include land use types, elevation, surface parameters (surface roughness
length, albedo, Bowen ratio, soil heat flux parameter, vegetation leaf area index), and anthropogenic heat
flux. An extensive description of GEO.DAT is provided in Section 8.
MAKEGEO requires 3 input files: a gridded elevation file (e.g. produced by TERREL) 2 , a gridded land
use file (e.g. generated by CTGPROC), and a user input control file (MAKEGEO.INP).
MAKEGEO reads gridded fractional land use, calculates dominant land use categories, as well as
weighted surface parameters and remaps to new LULC categories, if desired. In MAKEGEO.INP, the
user can define new Land Use categories by remapping the USGS Land Use categories. For example, the
USGS land use category system has 7 types of urban or built-up land and these would all be mapped to
one land use category for urban or built-up land in CALMET if using the 14 category system (see Table
8-6).
A value of each surface parameter is provided by the user for each land use category in the MAKEGEO
control input file. MAKEGEO computes area weighted values for each grid cell based on the amount of
area each land use category covers in the grid cell. For example, a grid cell which is half water and half
forest would have surface parameters that would reflect 50% of the value assigned to water and 50% of
the value assigned to forest categories. An arithmetic weighting is computed for albedo, Bowen ratio, soil
heat flux, vegetation leaf area index and anthropogenic heat flux. For the surface roughness, a
logarithmic weighting is used.
The format of the MAKEGEO control input file follows the same rules as those used in the
CALMET.INP file (refer to the CALMET section for details). Only data within the delimiter characters
(!) are processed. The input data consist of a leading delimiter followed by the variable name, equals
sign, input value or values, and a terminating delimiter (e.g., !XX = 12.5!). MAKEGEO.INP may be
created/edited directly using a conventional editor, or it may be created/edited indirectly by means of the
PC-based, Windows-compatible Graphical User Interface (GUI) developed for the geophysical
preprocessors (CALPRO). A sample MAKEGEO.INP file is provided in Table 2-14 and the input
variables are described in Table 2-15.
1
MAKEGEO also produces a binary “terrain” file suitable for input into UAM.
2
MAKEGEO will run if a gridded elevation file is not supplied, but gridded terrain elevations must then
be manually inserted into GEO.DAT before using as input for CALMET.
2-51