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sfvp2uvg

Computes the wind components given stream function and velocity potential (on a gaussian grid) via spherical harmonics.

Prototype

```	procedure sfvp2uvg (
sf  : numeric,
vp  : numeric,
u   : float,    ; or double
v   : float     ; or double
)
```

Arguments

sf

stream function array (input, array with two or more dimensions, last two dimensions must be nlat x nlon)

• input values must be in ascending latitude order
• input array must be on a global grid

vp

velocity potential array (input, same dimensions as sf)

• input values must be in ascending latitude order
• input array must be on a global grid

u
v

wind components (output, same dimensions as sf and vp, values will be in ascending latitude order)

Description

sfvp2uvg computes the wind components given stream function and divergent arrays sf and vp, and stores the results in the arrays u and v. sfvp2uvg operates on a gaussian grid. If the input arrays sf and vp are on a fixed grid, sfvp2uvf should be used.

This procedure does not handle missing values. If any missing values are encountered in a particular 2D input grid, then all of the values in the corresponding output grids will be set to the missing value defined by the output grids' _FillValue attributes.

Note: For the arrays whose last two dimensions are nlat x nlon, the rest of the dimensions (if any) are collectively referred to as N. If the input/output arrays are just two dimensions, then N can either be considered equal to 1 or nothing at all.

Arrays which have dimensions N x nlat x nlon should not include the cyclic (wraparound) points when invoking the procedures and functions which use spherical harmonics (Spherepack).

Examples

Example 1

```  u     = sf                    ; create arrays for u and v
v     = sf
sfvp2uvg (sf,vp, u,v)         ; sf,vp > reconstruct original wind

u@long_name = "Zonal Wind component"
v@long_name = "Meridional Wind component"

u@units     = "m/s"
v@units     = "m/s"
```

Errors

If jer or ker is equal to:

1 : error in the specification of nlat
2 : error in the specification of nlon
4 : error in the specification of N (jer only)