matlab_class/gcmfaces_smooth/diffsmooth2D.m

function [FLD]=diffsmooth2D(fld,dxCsm,dyCsm);
%object: diffusive smoother (after Weaver and Courtier 2001)
%
%input: fld               field to be smoothed (masked with NaN)
%       dxCsm,dyCsm       scale in first/second grid direction
%output:FLD               smoothed field
%
%asumption: dxCsm/dyCsm are given at U/V points (as DXC/DYC are)

global mygrid;

%scale the diffusive operator:
dxC=mygrid.DXC; dyC=mygrid.DYC;

tmp0=dxCsm./dxC; tmp0(isnan(fld))=NaN; tmp00=nanmax(tmp0);
tmp0=dyCsm./dyC; tmp0(isnan(fld))=NaN; tmp00=max([tmp00 nanmax(tmp0)]);
nbt=tmp00;
nbt=ceil(1.1*2*nbt^2);

dt=1;
T=nbt*dt;

%diffusion operator:
Kux=dxCsm.*dxCsm/T/2;
Kvy=dyCsm.*dyCsm/T/2;

%setup problem:
myOp.dt=1;
myOp.nbt=nbt;
myOp.Kux=Kux;
myOp.Kvy=Kvy;

%time step problem:
FLD=gcmfaces_timestep(myOp,fld);
1	function [FLD]=diffsmooth2D(fld,dxCsm,dyCsm);
2	%object: diffusive smoother (after Weaver and Courtier 2001)
3	%
4	%input: fld field to be smoothed (masked with NaN)
5	% dxCsm,dyCsm scale in first/second grid direction
6	%output:FLD smoothed field
7	%
8	%asumption: dxCsm/dyCsm are given at U/V points (as DXC/DYC are)
9
10	global mygrid;
11
12	%scale the diffusive operator:
13	dxC=mygrid.DXC; dyC=mygrid.DYC;
14
15	tmp0=dxCsm./dxC; tmp0(isnan(fld))=NaN; tmp00=nanmax(tmp0);
16	tmp0=dyCsm./dyC; tmp0(isnan(fld))=NaN; tmp00=max([tmp00 nanmax(tmp0)]);
17	nbt=tmp00;
18	nbt=ceil(1.12nbt^2);
19
20	dt=1;
21	T=nbt*dt;
22
23	%diffusion operator:
24	Kux=dxCsm.*dxCsm/T/2;
25	Kvy=dyCsm.*dyCsm/T/2;
26
27	%setup problem:
28	myOp.dt=1;
29	myOp.nbt=nbt;
30	myOp.Kux=Kux;
31	myOp.Kvy=Kvy;
32
33	%time step problem:
34	FLD=gcmfaces_timestep(myOp,fld);