Grid-to-grid procedures for vector quantities using Spherepack routines.
procedure f2fshv( ua : float, va : float, ub : float, vb : float ) procedure g2fshv( ua : float, va : float, ub : float, vb : float ) procedure f2gshv( ua : float, va : float, ub : float, vb : float, twave[1] : integer ) procedure g2gshv( ua : float, va : float, ub : float, vb : float, twave[1] : integer ) procedure fo2fshv( uoff : float, voff : float, ureg : float, vreg : float ) procedure f2foshv( ureg : float, vreg : float, uoff : float, voff : float )
(-90 ,0), (-90, 2.5),..., (-90, 357.5) (-87.5,0), (-87.5,2.5),..., (-87.5,357.5) . (0,0), (0,2.5), (0,5.0),..., (0,357.5) (2.5,0),(2.5,2.5),..., (2.5,357.5)For a 2.5 degree fixed/regular grid there are 73 latitude points and 144 longitude points. Both pole points are present.
Fixed offset grids are grids 'offset' from Grenwich meridian and equator. For example, a 2.5 x 2.5 degree fixed-offset grid has values at:
(-88.75,1.25), (-88.75,3.75),..., (-88.75,357.5)For a 2.5 degree fixed-offset grid there are 72 latitude points and 144 longitude points. There are no pole points.
.
(1.25,1.25), (1.25,3.75),...,(1.25,358.75)
(3,75,1.25), (3.75,3.75),...,(3.75,358.75)
g2gshv interpolates a vector pair from one Gaussian grid (ua,va) to another (ub,vb) (optional truncation) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except nlata and nlona are replaced by nlatb and nlonb.
g2fshv interpolates a vector pair on a Gaussian grid (ua,va) to a fixed grid (ub,va) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except nlata and nlona are replaced by nlatb and nlonb.
f2gshv interpolates a vector pair on a fixed grid (ua,va) to a Gaussian grid (ub,vb) (optional truncation) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except nlata and nlona are replaced by nlatb and nlonb.
f2fshv interpolates a vector pair from one fixed grid (ua,va) to another (ub,vb) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except nlata and nlona are replaced by nlatb and nlonb.
fo2fshv interpolates a vector pair on a fixed-offset grid (uoff,voff) (including pole points) to a fixed grid (ureg,vreg) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except jlat is replaced by jlat+1. For example, a 5 degree fixed-offset grid would have dimensions nlata=36, nlona=72, and the return fixed grid would have dimensions nlatb=37, nlonb=72.
f2foshv interpolates a vector pair on a fixed grid (ureg,vreg) (including pole points) to a fixed-offset grid (uoff,voff) using spherical harmonics. The output array dimensions must be the same as the input array dimensions, except jlat1 is replaced by jlat1-1. For example, a 5 degree fixed grid would have dimensions nlata=37, nlona=72, and the return fixed-offset grid would have dimensions nlatb=36, nlonb=72.
Arrays which have dimensions [...] x nlat x nlon should not include the cyclic (wraparound) points when invoking the procedures and functions which use spherical harmonics (Spherepack).
For example, if an array x has dimensions nlat = 64 and nlon = 129, where the "129" represents the cyclic points, then the user should pass the data to the procedure/function via:
z = sample ( x([...] :,0:nlon-2) ) ; does not include cyclic points
4 or 10 if nlona (ilon) is less than 4
5 or 10 if nlata (jlat) is less than 3
8 if nlonb is less than 4
9 if nlatb is less than 3
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