module gaussian_topog_mod¶

Overview¶

Routines for creating Gaussian-shaped land surface topography for latitude-longitude grids.

Interfaces generate simple Gaussian-shaped mountains from parameters specified by either argument list or namelist input. The mountain shapes are controlled by the height, half-width, and ridge-width parameters.

Other modules used¶

      fms_mod
constants_mod

Public interface¶

use gaussian_topog_mod [, only:  gaussian_topog_init,
                                 get_gaussian_topog ]

gaussian_topog_init:: Returns a surface height field that consists of the sum of one or more Gaussian-shaped mountains.
get_gaussian_topog:: Returns a simple surface height field that consists of a single Gaussian-shaped mountain.

Public data¶

None.

Public routines¶

Gaussian_topog_init
```
<B>call gaussian_topog_init </B> ( lon, lat, zsurf )
```
DESCRIPTION
Returns a land surface topography that consists of a “set” of simple Gaussian-shaped mountains. The height, position, width, and elongation of the mountains can be controlled by variables in namelist &gaussian_topog_nml.

INPUT

lon

The mean grid box longitude in radians. [real, dimension(:)]

lat

The mean grid box latitude in radians. [real, dimension(:)]

OUTPUT

zsurf

The surface height (in meters). The size of this field must be size(lon) by size(lat). [real, dimension(:,:)]

Get_gaussian_topog

zsurf = <B> get_gaussian_topog </B> ( lon, lat, height [, olond, olatd, wlond, wlatd, rlond, rlatd ] )

DESCRIPTION

Returns a single Gaussian-shaped mountain. The height, position, width, and elongation of the mountain is controlled by optional arguments.

INPUT

`lon`	The mean grid box longitude in radians. [real, dimension(:)]
`lat`	The mean grid box latitude in radians. [real, dimension(:)]
`height`	Maximum surface height in meters. [real, dimension(scalar)]
`olond, olatd`	Position/origin of mountain in degrees longitude and latitude. This is the location of the maximum height. [real, dimension(scalar)]
`wlond, wlatd`	Gaussian half-width of mountain in degrees longitude and latitude. [real, dimension(scalar)]
`rlond, rlatd`	Ridge half-width of mountain in degrees longitude and latitude. This is the elongation of the maximum height. [real, dimension(scalar)]

OUTPUT

zsurf

The surface height (in meters). The size of the returned field is size(lon) by size(lat). [real, dimension(:,:)]

NOTE

Mountains do not wrap around the poles.

Namelist¶

&gaussian_topog_nml height Height in meters of the Gaussian mountains. [real, dimension(mxmtns), units: meter, default: 0.] olon, olat The longitude and latitude of mountain origins (in degrees). [real, dimension(mxmtns), units: degree, default: 0.] wlon, wlat The longitude and latitude half-width of mountain tails (in degrees). [real, dimension(mxmtns), units: degree, default: 0.] rlon, rlat The longitude and latitude half-width of mountain ridges (in degrees). For a “standard” Gaussian mountain set rlon=rlat=0. [real, dimension(mxmtns), units: degree, default: 0.] NOTE The variables in this namelist are only used when routine <TT>gaussian_topog_init</TT> is called. The namelist variables are dimensioned (by 10), so that multiple mountains can be generated. Internal parameter mxmtns = 10. By default no mountains are generated. []

Data sets¶

None.

Error messages¶

FATAL in get_gaussian_topog: shape(zsurf) is not equal to (/size(lon),size(lat)/) Check the input grid size and output field size. The input grid is defined at the midpoint of grid boxes.

References¶

None.

Compiler specifics¶

None.

Precompiler options¶

None.

Loader options¶

None.

Test PROGRAM¶

None.

Notes¶

NAMELIST FOR GENERATING GAUSSIAN MOUNTAINS * multiple mountains can be generated * the final mountains are the sum of all height = height in meters olon, olat = longitude,latitude origin (degrees) rlon, rlat = longitude,latitude half-width of ridge (degrees) wlon, wlat = longitude,latitude half-width of tail (degrees) Note: For the standard gaussian mountain set rlon = rlat = 0 .

   height -->   ___________________________
               /                           \
              /              |              \
gaussian     /               |               \
  sides --> /                |                \
           /               olon                \
     _____/                olat                 \______

          |    |             |
          |<-->|<----------->|
          |wlon|    rlon     |
           wlat     rlat

See the topography module documentation for a test program.