ip_lambert_conf_grid_mod Module Reference

Lambert conformal grib decoder and grid coordinate transformations. More...

Data Types
type	ip_lambert_conf_grid

Functions/Subroutines
subroutine	gdswzd_lambert_conf (self, IOPT, NPTS, FILL, XPTS, YPTS, RLON, RLAT, NRET, CROT, SROT, XLON, XLAT, YLON, YLAT, AREA)
	GDS wizard for lambert conformal conical. More...
subroutine	init_grib1 (self, g1_desc)
	Initializes a Lambert Conformal grid given a grib1_descriptor object. More...
subroutine	init_grib2 (self, g2_desc)
	Initializes a Lambert Conformal grid given a grib2_descriptor object. More...
subroutine	lambert_conf_grid_area (RLAT, FILL, DR, AREA)
	Grid box area for lambert conformal conical. More...
subroutine	lambert_conf_map_jacob (RLAT, FILL, DLON, DR, XLON, XLAT, YLON, YLAT)
	Map jacobians for lambert conformal conical. More...
subroutine	lambert_conf_vect_rot (DLON, CROT, SROT)
	Vector rotation fields for lambert conformal conical. More...

Variables
real	an
	Cone factor. More...
real	dxs
	x-direction grid length adjusted for scan mode. More...
real	dys
	y-direction grid length adjusted for scan model. More...
real	h
	Hemisphere flag. More...
integer	irot
	vector rotation flag. More...
real	rerth
	Radius of the earth. More...

Detailed Description

Lambert conformal grib decoder and grid coordinate transformations.

Octet numbers refer to [GRIB2 - GRID DEFINITION TEMPLATE 3.30 Lambert conformal](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp3-30.shtml).

Author

Iredell

Date

96-04-10

Function/Subroutine Documentation

gdswzd_lambert_conf()

subroutine ip_lambert_conf_grid_mod::gdswzd_lambert_conf ( class(ip_lambert_conf_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 lambert conformal conical.

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 lambert conformal conical projections.

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, map jacobians and grid box areas for this grid 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
96-04-10	iredell	Initial.
96-10-01	iredell	protected against unresolvable points
97-10-20	iredell	include map options
1999-04-27	gilbert	corrected minor error calculating variable an for the secant projection case (rlati1.ne.rlati2).
2012-08-14	gayno	fix problem with sh grids. Ensure grid box area always positive.
2015-01-21	gayno	merger of gdswiz03() and gdswzd03(). 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.
2015-07-13	gayno	Convert to grib 2. Replace grib 1 kgds array with grib 2 grid definition template array. Rename routine.
2018-07-20	wesley	add threads.

Parameters

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

Author

Iredell

Date

96-04-10

Definition at line 219 of file ip_lambert_conf_grid_mod.F90.

References an, dxs, dys, h, irot, lambert_conf_grid_area(), lambert_conf_map_jacob(), lambert_conf_vect_rot(), and rerth.

init_grib1()

subroutine ip_lambert_conf_grid_mod::init_grib1 ( class(ip_lambert_conf_grid), intent(inout)  self, type(grib1_descriptor), intent(in)  g1_desc  )

private

Initializes a Lambert Conformal grid given a grib1_descriptor object.

Parameters

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

Author

Iredell

Date

96-04-10

Definition at line 60 of file ip_lambert_conf_grid_mod.F90.

init_grib2()

subroutine ip_lambert_conf_grid_mod::init_grib2 ( class(ip_lambert_conf_grid), intent(inout)  self, type(grib2_descriptor), intent(in)  g2_desc  )

private

Initializes a Lambert Conformal grid given a grib2_descriptor object.

Parameters

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

Author

Iredell

Date

96-04-10

Definition at line 112 of file ip_lambert_conf_grid_mod.F90.

lambert_conf_grid_area()

subroutine ip_lambert_conf_grid_mod::lambert_conf_grid_area ( real, intent(in)  RLAT, real, intent(in)  FILL, real, intent(in)  DR, real, intent(out)  AREA  )

private

Grid box area for lambert conformal conical.

This subprogram computes the grid box area for a lambert conformal conical grid.

Program History Log

Date	Programmer	Comments
2015-01-21	Gayno	initial version
2015-09-17	Gayno	rename as "lambert_conf_grid_area"
2018-07-20	Wesley	pass in dr for threading.

Parameters

[in]	rlat	latitude of grid point in degrees (real)
[in]	fill	fill value for undefined points (real)
[in]	dr	distance from pole point (real)
[out]	area	area weights in m**2 (real)

Author

Gayno

Date

2015-01-21

Definition at line 468 of file ip_lambert_conf_grid_mod.F90.

References an, dxs, dys, and rerth.

Referenced by gdswzd_lambert_conf().

lambert_conf_map_jacob()

subroutine ip_lambert_conf_grid_mod::lambert_conf_map_jacob ( real, intent(in)  RLAT, real, intent(in)  FILL, real, intent(in)  DLON, real, intent(in)  DR, real, intent(out)  XLON, real, intent(out)  XLAT, real, intent(out)  YLON, real, intent(out)  YLAT  )

private

Map jacobians for lambert conformal conical.

This subprogram computes the map jacobians for a lambert conformal conical grid.

Program History Log

Date	Programmer	Comments
2015-01-21	Gayno	initial version
2015-09-17	Gayno	rename as "lambert_conf_map_jacob"
2018-07-20	Wesley	pass dlon and dr for threading.

Parameters

[in]	rlat	grid point latitude in degrees (real)
[in]	fill	fill value for undefined points (real)
[in]	dlon	distance from orientation longitude (real)
[in]	dr	distance from pole point (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 427 of file ip_lambert_conf_grid_mod.F90.

References an, dxs, dys, and h.

Referenced by gdswzd_lambert_conf().

lambert_conf_vect_rot()

subroutine ip_lambert_conf_grid_mod::lambert_conf_vect_rot ( real, intent(in)  DLON, real, intent(out)  CROT, real, intent(out)  SROT  )

private

Vector rotation fields for lambert conformal conical.

This subprogram computes the vector rotation sines and cosines for a lambert conformal conical grid.

Program History Log

Date	Programmer	Comments
2015-01-21	gayno	initial version
2015-09-17	gayno	rename as "lambert_conf_vect_rot"
2018-07-20	wesley	pass in dlon for threading.

Parameters

[in]	dlon	from orientation longitude (real)
[out]	crot	vector rotation cosines (real)
[out]	srot	vector rotation sines (real) (ugrid=crot*uearth-srot*vearth; vgrid=srot*uearth+crot*vearth)

Author

Gayno

Date

2015-01-21

Definition at line 390 of file ip_lambert_conf_grid_mod.F90.

References an, and irot.

Referenced by gdswzd_lambert_conf().

Variable Documentation

an

real ip_lambert_conf_grid_mod::an

private

Cone factor.

Definition at line 45 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), lambert_conf_grid_area(), lambert_conf_map_jacob(), and lambert_conf_vect_rot().

dxs

real ip_lambert_conf_grid_mod::dxs

private

x-direction grid length adjusted for scan mode.

GRIB2, Section 3, octets 56-59.

Definition at line 46 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), lambert_conf_grid_area(), and lambert_conf_map_jacob().

dys

real ip_lambert_conf_grid_mod::dys

private

y-direction grid length adjusted for scan model.

GRIB2, Section 3, octets 60-63.

Definition at line 47 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), lambert_conf_grid_area(), and lambert_conf_map_jacob().

h

real ip_lambert_conf_grid_mod::h

private

Hemisphere flag.

1-NH, minus 1-SH.

Definition at line 48 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), and lambert_conf_map_jacob().

irot

integer ip_lambert_conf_grid_mod::irot

private

vector rotation flag.

When "1", vectors are grid relative. When "0", vectors are earth relative. GRIB2, Section 3, octet 55.

Definition at line 44 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), and lambert_conf_vect_rot().

rerth

real ip_lambert_conf_grid_mod::rerth

private

Radius of the earth.

GRIB2, Section 3, octets 15-30.

Definition at line 49 of file ip_lambert_conf_grid_mod.F90.

Referenced by gdswzd_lambert_conf(), and lambert_conf_grid_area().