topography_mod

Routines for creating land surface topography fields and land-water masks for latitude-longitude grids. More...

Data Types
interface	get_ocean_frac
	Returns fractional area covered by ocean in a grid box. Returns fractional area covered by ocean in the given model grid boxes. More...
interface	get_ocean_mask
	Returns a land-ocean mask in a grid box. More...
interface	get_topog_mean
	Returns a "realistic" mean surface height field. More...
interface	get_water_frac
	Returns fractional area covered by water. More...
interface	get_water_mask
	Returns a land-water mask in a grid box. More...

Functions/Subroutines
logical function	open_topog_file ()
logical function	open_water_file ()
subroutine	read_namelist
	Reads the namelist file, write namelist to log file, and initializes constants.
subroutine, public	topography_init ()

Variables
integer, parameter	compute_stdev = 123
logical, dimension(2)	file_is_opened = .false.
type(fmsnetcdffile_t), dimension(2)	fileobj
	needed for fms2_io
integer	ipts
integer	jpts
logical	module_is_initialized = .FALSE.
character(len=fms_path_len)	topog_file = 'DATA/navy_topography.data'
integer, parameter	topog_index = 1
character(len=fms_path_len)	water_file = 'DATA/navy_pctwater.data'
integer, parameter	water_index = 2

Detailed Description

Routines for creating land surface topography fields and land-water masks for latitude-longitude grids.

Author

Bruce Wyman

This module generates realistic mountains and land-water masks on a specified latitude-longitude grid by interpolating from the 1/6 degree Navy mean topography and percent water data sets. The fields that can be generated are mean and standard deviation of topography within the specified grid boxes; and land-ocean (or water) mask and land-ocean (or water) fractional area.

The interpolation scheme conserves the area-weighted average of the input data by using module horiz_interp.

The interfaces get_gaussian_topog and gaussian_topog_init are documented in gaussian_topog_mod

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Data Type Documentation

topography_mod::get_ocean_frac

interface topography_mod::get_ocean_frac

Returns fractional area covered by ocean in a grid box. Returns fractional area covered by ocean in the given model grid boxes.

Parameters

blon	The longitude (in radians) at grid box boundaries.
blat	The latitude (in radians) at grid box boundaries.
ocean_frac	The fractional amount (0 to 1) of ocean in a grid box. The size of this field must be size(blon)-1 by size(blat)-1.

Returns

A logical value of TRUE is returned if the output field was successfully created. A value of FALSE may be returned if the Navy 1/6 degree percent water data set was not readable.

Example usage:

flag = get_ocean_frac( blon, blat, ocean_frac ) 

Definition at line 129 of file topography.F90.

Private Member Functions
	get_ocean_frac_1d_r4
	get_ocean_frac_1d_r8
	get_ocean_frac_2d_r4
	get_ocean_frac_2d_r8

topography_mod::get_ocean_mask

interface topography_mod::get_ocean_mask

Returns a land-ocean mask in a grid box.

Returns a land-ocean mask in the given model grid boxes.

Parameters

blon	The longitude (in radians) at grid box boundaries.
blat	The latitude (in radians) at grid box boundaries.
ocean_frac	The fractional amount (0 to 1) of ocean in a grid box. The size of this field must be size(blon)-1 by size(blat)-1.

Returns

A logical value of TRUE is returned if the output field was successfully created. A value of FALSE may be returned if the Navy 1/6 degree percent water data set was not readable.

Example code:

flag = get_ocean_mask( blon, blat, ocean_mask ) 

Definition at line 150 of file topography.F90.

Private Member Functions
	get_ocean_mask_1d_r4
	get_ocean_mask_1d_r8
	get_ocean_mask_2d_r4
	get_ocean_mask_2d_r8

topography_mod::get_topog_mean

interface topography_mod::get_topog_mean

Returns a "realistic" mean surface height field.

Returns realistic mountains on a latitude-longtude grid. The returned field is the mean topography for the given grid boxes. Computed using a conserving area-weighted interpolation. The current input data set is the 1/6 degree Navy mean topography.

Parameters

blon	The longitude (in radians) at grid box boundaries.
blat	The latitude (in radians) at grid box boundaries.
zmean	The mean surface height (meters). The size of this field must be size(blon)-1 by size(blat)-1.

Returns

A logical value of TRUE is returned if the surface height field was successfully created. A value of FALSE may be returned if the input topography data set was not readable.

Example usage:

flag = get_topog_mean( blon, blat, zmean )

Definition at line 84 of file topography.F90.

Private Member Functions
	get_topog_mean_1d_r4
	get_topog_mean_1d_r8
	get_topog_mean_2d_r4
	get_topog_mean_2d_r8

topography_mod::get_water_frac

interface topography_mod::get_water_frac

Returns fractional area covered by water.

Returns the percent of water in a grid box.

Parameters

	blon	The longitude (in radians) at grid box boundaries.
	blat	The latitude (in radians) at grid box boundaries.
[out]	water_frac	The fractional amount (0 to 1) of water in a grid box. The size of this field must be size(blon)-1 by size(blat)-1.

Returns

A logical value of TRUE is returned if the output field was successfully created. A value of FALSE may be returned if the Navy 1/6 degree percent water data set was not readable.

Example usage:

flag = get_water_frac( blon, blat, water_frac ) 

Definition at line 170 of file topography.F90.

Private Member Functions
	get_water_frac_1d_r4
	get_water_frac_1d_r8
	get_water_frac_2d_r4
	get_water_frac_2d_r8

topography_mod::get_water_mask

interface topography_mod::get_water_mask

Returns a land-water mask in a grid box.

Returns a land-water mask in the given model grid boxes.

Parameters

blon	The longitude (in radians) at grid box boundaries.
blat	The latitude (in radians) at grid box boundaries.
water_mask	A binary mask for water (true) or land (false). The size of this field must be size(blon)-1 by size(blat)-1.

Returns

A logical value of TRUE is returned if the output field was successfully created. A value of FALSE may be returned if the Navy 1/6 degree percent water data set was not readable.

Example usage:

flag = get_water_mask( blon, blat, water_mask ) 

Definition at line 190 of file topography.F90.

Private Member Functions
	get_water_mask_1d_r4
	get_water_mask_1d_r8
	get_water_mask_2d_r4
	get_water_mask_2d_r8