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Computation/

norm.pro

calculate the norm of vectors field located on Arakawa C-grid

topnorm Calculation

result = norm(uu, vv, DIREC=DIREC, _EXTRA=_EXTRA)

Return value

a 2D (xy), 3D (xyz or yt), 4D (xyzt) array

Parameters

uu        in required

Matrix representing the zonal coordinates (at U/V point) of a field of vectors A 2D (xy), 3D (xyz or yt), 4D (xyzt) or a structure readable by litchamp and containing a 2D (xy), 3D (xyz or yt), 4D (xyzt) array. Note that the dimension of the array must suit the domain dimension.

vv        in required

Matrix representing the meridional coordinates (at V/U point) of a field of vectors A 2D (xy), 3D (xyz or yt), 4D (xyzt) array or a structure readable by litchamp and containing a 2D (xy), 3D (xyz or yt), 4D (xyzt) array. Note that the dimension of the array must suit the domain dimension.

Keywords

DIREC       

't' 'x' 'y' 'z' 'xys' 'xz' 'yz' 'xyz' 'xt' 'yt' 'zt' 'xyt' 'xzt' 'yzt' 'xyzt' Direction on which do averages

_EXTRA       

Used to declare that this routine accepts inherited keywords

Examples

To calculate the average of the norm of streams on all the domain between 0 and 50: IDL> domdef, 0, 50 IDL> res = norm(un, vn, dir = 'xyz')

Version history

Version

$Id: norm.pro 371 2008-08-07 09:32:02Z pinsard $

History

Sebastien Masson (smasson@lodyc.jussieu.fr) 9/6/1999

Known issues

Restrictions

The norm is calculated on points T. To do this calculation, we average field U and V on points T before calculate the norm. At the edge of coast and of domain, we can not calculate fields U and V at points T, that is why these points are at value !values.f_nan. When we calculate on a reduce geographic domain, field U and V have not necessarily the same number of point. In this case, we recut U and V to keep only common points. We profit of this to redo a domdef which redefine a geographic domain on which fields U and V are extracted on same points To know what type of array we work with, we test its size and dates gave by time[0] and time[jpt-1] to know if thee is a temporal dimension. Before to start norm, make sure that time and jpt are defined how they have to!

Other attributes

Uses routines

cm_4mesh cm_4data cm_4cal

Statistics

McCabe cyclic 121
McCabe essential 1
McCabe modular design 1
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