ip_rot_equid_cylind_grid_mod Module Reference

Rotated equidistant cylindrical GRIB decoder and grid coordinate transformations for Arakawa grids A through D. More...

Data Types
type	ip_rot_equid_cylind_grid

Functions/Subroutines
subroutine	gdswzd_rot_equid_cylind (self, IOPT, NPTS, FILL, XPTS, YPTS, RLON, RLAT, NRET, CROT, SROT, XLON, XLAT, YLON, YLAT, AREA)
	GDS wizard for rotated equidistant cylindrical. More...
subroutine	init_grib1 (self, g1_desc)
	Initializes a Rotated equidistant cylindrical grid given a grib1_descriptor object. More...
subroutine	init_grib2 (self, g2_desc)
	Initializes a Rotated equidistant cylindrical grid given a grib2_descriptor object. More...
subroutine	rot_equid_cylind_error (IOPT, FILL, RLAT, RLON, XPTS, YPTS, NPTS)
	Error handler. More...
subroutine	rot_equid_cylind_grid_area (CLATR, FILL, AREA)
	Grid box area for rotated equidistant cylindrical grids - non "e" stagger. More...
subroutine	rot_equid_cylind_map_jacob (FILL, RLON, CLATR, CLAT, SLAT, CLON, XLON, XLAT, YLON, YLAT)
	Map jacobians for rotated equidistant cylindrical grids - non "e" stagger. More...
subroutine	rot_equid_cylind_vect_rot (RLON, CLATR, SLATR, CLAT, SLAT, CLON, CROT, SROT)
	Vector rotation fields for rotated equidistant cylindrical grids - non "e" stagger. More...

Variables
real(kind=kd)	clat0
	Local copy of clat0. More...
real(kind=kd)	dlats
	Local copy of dlats. More...
real(kind=kd)	dlons
	Local copy of dlons. More...
integer	irot
	Local copy of irot. More...
integer, parameter	kd = real64
	Fortran kind for reals. More...
real(kind=kd)	rerth
	Radius of the Earth. More...
real(kind=kd)	rlon0
	Local copy of rlon0. More...
real(kind=kd)	slat0
	Local copy of slat0. More...

Detailed Description

Rotated equidistant cylindrical GRIB decoder and grid coordinate transformations for Arakawa grids A through D.

(To handle the E grid, see ip_rot_equid_cylind_egrid_mod).

See more info about Awakawa grids.

Octet numbers refer to GRIB2 - GRID DEFINITION TEMPLATE 3.1 Rotate Latitude/Longitude.

Author

Gayno

Date

2007-NOV-15

Function/Subroutine Documentation

gdswzd_rot_equid_cylind()

subroutine ip_rot_equid_cylind_grid_mod::gdswzd_rot_equid_cylind ( class(ip_rot_equid_cylind_grid), intent(in)  self, integer, intent(in)  IOPT, integer, intent(in)  NPTS, real, intent(in)  FILL, real, dimension(npts), intent(inout)  XPTS, real, dimension(npts), intent(inout)  YPTS, real, dimension(npts), intent(inout)  RLON, real, dimension(npts), intent(inout)  RLAT, integer, intent(out)  NRET, real, dimension(npts), intent(out), optional  CROT, real, dimension(npts), intent(out), optional  SROT, real, dimension(npts), intent(out), optional  XLON, real, dimension(npts), intent(out), optional  XLAT, real, dimension(npts), intent(out), optional  YLON, real, dimension(npts), intent(out), optional  YLAT, real, dimension(npts), intent(out), optional  AREA  )

private

GDS wizard for rotated equidistant cylindrical.

This subprogram decodes the grib 2 grid definition template (passed in integer form as decoded by the ncep g2 library) and returns one of the following:

• (iopt=+1) earth coordinates of selected grid coordinates
• (iopt=-1) grid coordinates of selected earth coordinates

Works for non-"e" staggered rotated equidistant cylindrical projections. the scan mode (section 3, octet 72, bits 5-6) determine whether this is an "h" or "v" grid.

If the selected coordinates are more than one gridpoint beyond the the edges of the grid domain, then the relevant output elements are set to fill values. The actual number of valid points computed is returned too.

Optionally, the vector rotations, the map jacobians and the grid box areas may be returned as well.

To compute the vector rotations, the optional arguments 'srot' and 'crot' must be present. To compute the map jacobians, the optional arguments 'xlon', 'xlat', 'ylon', 'ylat' must be present. To compute the grid box areas, the optional argument 'area' must be present.

Program History Log

Date	Programmer	Comments
2010-jan-15	gayno	based on routines gdswzdcb and gdswzdca
2015-jan-21	gayno	merger of gdswizcd and gdswzdcd. make crot,sort,xlon,xlat,ylon,ylat and area optional arguments. make part of a module. move vector rotation, map jacobian and grid box area computations to separate subroutines.
2015-jul-13	gayno	convert to grib 2. replace grib 1 kgds array with grib 2 grid definition template array. rename as "gdswzd_rot_equid_cylind."
2018-07-20	wesley	add threads.

Parameters

[in]	self	Module reference.
[in]	iopt	integer option flag 1 to compute earth coords of selected grid coords -1 to compute grid coords of selected earth coords
[in]	npts	integer maximum number of coordinates
[in]	fill	real fill value to set invalid output data (must be impossible value; suggested value: -9999.)
[in,out]	xpts	real (npts) grid x point coordinates if iopt>0
[in,out]	ypts	real (npts) grid y point coordinates if iopt>0
[in,out]	rlon	real (npts) earth longitudes in degrees e if iopt<0 (acceptable range: -360. to 360.)
[in,out]	rlat	real (npts) earth latitudes in degrees n if iopt<0 (acceptable range: -90. to 90.)
[out]	nret	integer number of valid points computed
[out]	crot	real, optional (npts) clockwise vector rotation cosines
[out]	srot	real, optional (npts) clockwise vector rotation sines (ugrid=crot*uearth-srot*vearth; vgrid=srot*uearth+crot*vearth)
[out]	xlon	real, optional (npts) dx/dlon in 1/degrees
[out]	xlat	real, optional (npts) dx/dlat in 1/degrees
[out]	ylon	real, optional (npts) dy/dlon in 1/degrees
[out]	ylat	real, optional (npts) dy/dlat in 1/degrees
[out]	area	real, optional (npts) area weights in m**2

Author

Gayno

Date

2007-NOV-15

Definition at line 256 of file ip_rot_equid_cylind_grid_mod.F90.

References clat0, dlats, dlons, irot, rerth, rlon0, rot_equid_cylind_error(), rot_equid_cylind_grid_area(), rot_equid_cylind_map_jacob(), rot_equid_cylind_vect_rot(), and slat0.

init_grib1()

subroutine ip_rot_equid_cylind_grid_mod::init_grib1 ( class(ip_rot_equid_cylind_grid), intent(inout)  self, type(grib1_descriptor), intent(in)  g1_desc  )

private

Initializes a Rotated equidistant cylindrical grid given a grib1_descriptor object.

Parameters

[in,out]	self	The grid to initialize
[in]	g1_desc	A grib1_descriptor

Author

Gayno

Date

2007-NOV-15

Definition at line 73 of file ip_rot_equid_cylind_grid_mod.F90.

References ip_constants_mod::dpr.

init_grib2()

subroutine ip_rot_equid_cylind_grid_mod::init_grib2 ( class(ip_rot_equid_cylind_grid), intent(inout)  self, type(grib2_descriptor), intent(in)  g2_desc  )

private

Initializes a Rotated equidistant cylindrical grid given a grib2_descriptor object.

Parameters

[in,out]	self	The grid to initialize
[in]	g2_desc	A grib2_descriptor

Author

Gayno

Date

2007-NOV-15

Definition at line 139 of file ip_rot_equid_cylind_grid_mod.F90.

rot_equid_cylind_error()

subroutine ip_rot_equid_cylind_grid_mod::rot_equid_cylind_error ( integer, intent(in)  IOPT, real, intent(in)  FILL, real, dimension(npts), intent(out)  RLAT, real, dimension(npts), intent(out)  RLON, real, dimension(npts), intent(out)  XPTS, real, dimension(npts), intent(out)  YPTS, integer, intent(in)  NPTS  )

private

Error handler.

Upon an error, this subprogram assigns a "fill" value to the output fields.

Parameters

[in]	iopt	integer option flag +1 to compute earth coords of selected grid coords -1 to compute grid coords of selected earth coords
[in]	fill	real fill value to set invalid output data (must be impossible value; suggested value: -9999.)
[out]	rlat	real (npts) earth latitudes in degrees n if iopt<0
[out]	rlon	real (npts) earth longitudes in degrees e if iopt<0
[out]	xpts	real (npts) grid x point coordinates if iopt>0
[out]	ypts	real (npts) grid y point coordinates if iopt>0
[in]	npts	integer maximum number of coordinates

Author

Gayno

Date

2015-07-13

Definition at line 462 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind().

rot_equid_cylind_grid_area()

subroutine ip_rot_equid_cylind_grid_mod::rot_equid_cylind_grid_area ( real(kind=kd), intent(in)  CLATR, real, intent(in)  FILL, real, intent(out)  AREA  )

private

Grid box area for rotated equidistant cylindrical grids - non "e" stagger.

This subprogram computes the grid box area for a rotated equidistant cylindrical grid - non "e" stagger.

Program History Log

Date	Programmer	Comments
2015-01-21	Gayno	initial version
2015-07-19	gayno	rename as "rot_equid_cylind_grid_area."
2018-07-20	wesley	pass in clatr for threading

Parameters

[in]	clatr	cosine of unrotated latitude (real)
[in]	fill	fill value for undefined points (real)
[out]	area	area weights in m**2 (real)

Author

Gayno

Date

2015-01-21

Definition at line 603 of file ip_rot_equid_cylind_grid_mod.F90.

References dlats, dlons, and rerth.

Referenced by gdswzd_rot_equid_cylind().

rot_equid_cylind_map_jacob()

subroutine ip_rot_equid_cylind_grid_mod::rot_equid_cylind_map_jacob ( real, intent(in)  FILL, real, intent(in)  RLON, real(kind=kd), intent(in)  CLATR, real(kind=kd), intent(in)  CLAT, real(kind=kd), intent(in)  SLAT, real(kind=kd), intent(in)  CLON, real, intent(out)  XLON, real, intent(out)  XLAT, real, intent(out)  YLON, real, intent(out)  YLAT  )

private

Map jacobians for rotated equidistant cylindrical grids - non "e" stagger.

This subprogram computes the map jacobians for a rotated equidistant cylindrical grid - non "e" stagger.

Program History Log

Date	Programmer	Comments
2015-01-21	gayno	initial version
2015-09-17	gayno	rename as "rot_equid_cylind_map_jacob".
2018-07-20	wesley	pass in clatr, clat, slat, clon to allow threading.

Parameters

[in]	fill	fill value for undefined points (real)
[in]	rlon	longitude in degrees (real)
[in]	clatr	cosine of unrotated latitude (real)
[in]	clat	cosine of latitude (real)
[in]	slat	sine of latitude (real)
[in]	clon	cosine of latitude (real)
[out]	xlon	dx/dlon in 1/degrees (real)
[out]	xlat	dx/dlat in 1/degrees (real)
[out]	ylon	dy/dlon in 1/degrees (real)
[out]	ylat	dy/dlat in 1/degrees (real)

Author

Gayno

Date

2015-01-21

Definition at line 558 of file ip_rot_equid_cylind_grid_mod.F90.

References clat0, dlats, dlons, rlon0, and slat0.

Referenced by gdswzd_rot_equid_cylind().

rot_equid_cylind_vect_rot()

subroutine ip_rot_equid_cylind_grid_mod::rot_equid_cylind_vect_rot ( real, intent(in)  RLON, real(kind=kd), intent(in)  CLATR, real(kind=kd), intent(in)  SLATR, real(kind=kd), intent(in)  CLAT, real(kind=kd), intent(in)  SLAT, real(kind=kd), intent(in)  CLON, real, intent(out)  CROT, real, intent(out)  SROT  )

private

Vector rotation fields for rotated equidistant cylindrical grids - non "e" stagger.

This subprogram computes the vector rotation sines and cosines for a rotated equidistant cylindrical grid - non "e" stagger.

Program History Log

Date	Programmer	Comments
2015-01-21	gayno	initial version
2015-07-19	gayno	rename as "rot_equid_cylind_vect_rot."
2018-07-20	wesley	pass in clatr, slatr, clat, slat, clon for threading.

Parameters

[in]	rlon	longitude in degrees (real)
[in]	clatr	cosine of rotated latitude (real)
[in]	slatr	sine of rotated latitude (real)
[in]	clat	cosine of latitude (real)
[in]	slat	sine of latitude (real)
[in]	clon	cosine of longitude (real)
[out]	crot	clockwise vector rotation cosines (real)
[out]	srot	clockwise vector rotation sines (real) (ugrid=crot*uearth-srot*vearth; vgrid=srot*uearth+crot*vearth)

Author

Gayno

Date

2015-01-21

Definition at line 507 of file ip_rot_equid_cylind_grid_mod.F90.

References clat0, irot, rlon0, and slat0.

Referenced by gdswzd_rot_equid_cylind().

Variable Documentation

clat0

real(kind=kd) ip_rot_equid_cylind_grid_mod::clat0

private

Local copy of clat0.

Definition at line 58 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), rot_equid_cylind_map_jacob(), and rot_equid_cylind_vect_rot().

dlats

real(kind=kd) ip_rot_equid_cylind_grid_mod::dlats

private

Local copy of dlats.

Definition at line 59 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), rot_equid_cylind_grid_area(), and rot_equid_cylind_map_jacob().

dlons

real(kind=kd) ip_rot_equid_cylind_grid_mod::dlons

private

Local copy of dlons.

Definition at line 60 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), rot_equid_cylind_grid_area(), and rot_equid_cylind_map_jacob().

irot

integer ip_rot_equid_cylind_grid_mod::irot

private

Local copy of irot.

Definition at line 56 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), and rot_equid_cylind_vect_rot().

kd

integer, parameter ip_rot_equid_cylind_grid_mod::kd = real64

private

Fortran kind for reals.

Definition at line 30 of file ip_rot_equid_cylind_grid_mod.F90.

rerth

real(kind=kd) ip_rot_equid_cylind_grid_mod::rerth

private

Radius of the Earth.

Definition at line 57 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), and rot_equid_cylind_grid_area().

rlon0

real(kind=kd) ip_rot_equid_cylind_grid_mod::rlon0

private

Local copy of rlon0.

Definition at line 61 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), rot_equid_cylind_map_jacob(), and rot_equid_cylind_vect_rot().

slat0

real(kind=kd) ip_rot_equid_cylind_grid_mod::slat0

private

Local copy of slat0.

Definition at line 62 of file ip_rot_equid_cylind_grid_mod.F90.

Referenced by gdswzd_rot_equid_cylind(), rot_equid_cylind_map_jacob(), and rot_equid_cylind_vect_rot().