uv2sfvpF

Computes the stream function and velocity potential via spherical harmonics given u and v on a fixed grid.

Prototype

	function uv2sfvpF (
		u  : numeric,  
		v  : numeric   
	)

	return_val [2,dimsizes(u)] :  float or double

Arguments

wind components (input, arrays with two or more dimensions, rightmost two dimensions must be nlat x nlon)

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

Return value

The returned array will be dimensioned 2 x dimsizes(u), where the leftmost 0-th dimension contains the stream function and the leftmost 1-th dimension contains the velocity potential (both in ascending latitude order). The array returned will be of type double if the input is double, and float otherwise.

Description

Given wind components u and v, uv2sfvpF computes the stream function and the velocity potential. uv2sfvpF operates on a fixed grid.

This function does not handle missing values (defined by the _FillValue attribute). 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.

Input arrays should not include the cyclic (wraparound) points when invoking this function, or any procedure or function which uses spherical harmonics (Spherepack).

If the input arrays u and v are on a gaussian grid, uv2sfvpG should be used. Also, note that uv2sfvpF is the function version of uv2sfvpf.

See Also

uv2sfvpf, uv2sfvpG, uv2sfvpg,uv2vrf

Examples

Example 1

Compute the stream function and velocity potential, given the u and v wind components on a fixed grid.

begin
  nlat  =  73                                       ; dimensions
  mlon  = 144
  mlon1 = mlon+1
  fbfile = "uv300.hs"
                                       ; Generic Workstation setup 
  nrec  = fbinnumrec(fbfile)       ; total number of records in the file
  ntim  = nrec/2                       ; number of time steps in dataset

  uvmsg = 1e+36

  do i = 0,nrec-1,2                    
   month = 1                         ; january
   if (i .ge. 2) then
       month = 7                     ; july
   end if   

   work = fbinrecread(fbfile,i  ,(/nlat,mlon1/),"float")
   u    = work(:,0:mlon-1)
   work = fbinrecread(fbfile,i+1,(/nlat,mlon1/),"float")
   v    = work(:,0:mlon-1)

   sfvp  = uv2sfvpF (u,v)             ; u,v ==> stream function + velocity pot
  end do
end

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)