| 1 |
function [fld]=gcmfaces_remap_2d(lon,lat,fld,nDblRes,varargin); |
| 2 |
%object: use bin average to remap ONE lat-lon grid FIELD to a gcmfaces grid |
| 3 |
%input: lon,lat,fld are the gridded product arrays |
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% nDblRes is the number of times the input field |
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% resolution should be doubled before bin average. |
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%optional: mskExtrap is the mask to which to extrapolate after bin average |
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% If it is not specified we do no extrapolation |
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%note: nDblRes>0 is useful if the starting resolution is coarse |
| 9 |
% enough that the bin average would leave many empty points. |
| 10 |
%assumption:fld should show NaN for missing values |
| 11 |
|
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global mygrid; |
| 13 |
if nargin>4; mskExtrap=varargin{1}; else; mskExtrap=[]; end; |
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|
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%apply meshgrid if not already the case |
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|
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%switch longitude range to 0-360 if not already the case |
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if ~isempty(find(lon(:,1)<0)); |
| 19 |
ii=max(find(lon(:,1)<0)); |
| 20 |
lon=circshift(lon,[-ii 0]); |
| 21 |
lon(end-ii+1:end,:)=lon(end-ii+1:end,:)+360; |
| 22 |
fld=circshift(fld,[-ii 0]); |
| 23 |
end; |
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|
| 25 |
%refine grid before bin average: |
| 26 |
for ii=1:nDblRes; |
| 27 |
[lon,lat,fld]=dbl_res(lon,lat,fld,ii); |
| 28 |
end; |
| 29 |
%put in vector form: |
| 30 |
tmp1=find(~isnan(fld)); |
| 31 |
lon=lon(tmp1); lat=lat(tmp1); fld=fld(tmp1); |
| 32 |
%switch longitude range to -180+180 |
| 33 |
lon(find(lon>180))=lon(find(lon>180))-360; |
| 34 |
%compute bin average: |
| 35 |
fld=gcmfaces_bindata(lon,lat,fld); |
| 36 |
%potential extrapolation: |
| 37 |
if ~isempty(mskExtrap); fld=diffsmooth2D_extrap_inv(fld,mskExtrap); end; |
| 38 |
%apply surface land mask: |
| 39 |
fld=fld.*mygrid.mskC(:,:,1); |
| 40 |
|
| 41 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 42 |
|
| 43 |
function [lonOut,latOut,obsOut]=dbl_res(lon,lat,obs,extendNaN); |
| 44 |
%object: use neighbor average to double the fields resolution |
| 45 |
%inputs: lon,lat,fld are the gridded product arrays, with |
| 46 |
% NaN for missing values in fld. |
| 47 |
% extendNaN states whether between a real and a NaN |
| 48 |
% we add a NaN (extendNaN==1) or a real (extendNaN~=1) |
| 49 |
%outputs: lonOut,latOut,fldOut are the x2 resolution arrays |
| 50 |
% |
| 51 |
%assumptions: 0-360 longitudes and a consistent ordering of arrays |
| 52 |
|
| 53 |
%check longitude range: |
| 54 |
if ~isempty(find(lon(:)<0))|~isempty(find(lon(:)>360)); fprintf('problem in longitude specs\n'); return; end; |
| 55 |
%check simple ordering: |
| 56 |
tmp1=diff(lon(:,1)); if ~isempty(find(tmp1<=0)); fprintf('problem in longitude specs\n'); return; end; |
| 57 |
|
| 58 |
%make sure that we are >=0 and <360: |
| 59 |
if lon(1,1)>0&lon(end,1)==360; lon=[lon(end,:)-360;lon(1:end-1,:)]; |
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lat=[lat(end,:);lat(1:end-1,:)]; obs=[obs(end,:);obs(1:end-1,:)]; end; |
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%make sure that the last point is not duplicated: |
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if lon(1,1)==0&lon(end,1)==360; lon=lon(1:end-1,:); |
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lat=lat(1:end-1,:); obs=obs(1:end-1,:); end; |
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|
| 65 |
%what do we do with last longitude points: |
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if lon(1,1)>0&lon(end,1)<360; |
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addOnePt=1; %add point at the beginning |
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else; |
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addOnePt=2; %add point at the end |
| 70 |
end; |
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|
| 72 |
for ii=1:3; |
| 73 |
%0) get field |
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if ii==1; tmpA=lon; |
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elseif ii==2; tmpA=lat; |
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elseif ii==3; tmpA=obs; |
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end; |
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|
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%1) zonal direction: |
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tmpB=nanmean2flds(tmpA(1:end-1,:),tmpA(2:end,:),extendNaN); |
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tmpC=ones(size(tmpA,1)*2-1,size(tmpA,2)); |
| 82 |
tmpC(1:2:end,:)=tmpA; |
| 83 |
tmpC(2:2:end-1,:)=tmpB; |
| 84 |
%treat zonal edge of the domain |
| 85 |
if addOnePt==1; %add one point at the beginning |
| 86 |
if ii==1; offset=-360; else; offset=0; end; |
| 87 |
tmpB=nanmean2flds(tmpA(1,:),offset+tmpA(end,:),extendNaN); tmpC=[tmpB;tmpC]; |
| 88 |
end; |
| 89 |
if addOnePt==2; %add one point at the end |
| 90 |
if ii==1; offset=360; else; offset=0; end; |
| 91 |
tmpB=nanmean2flds(offset+tmpA(1,:),tmpA(end,:),extendNaN); tmpC=[tmpC;tmpB]; |
| 92 |
end; |
| 93 |
%check that we did not go too far (should not happen) |
| 94 |
if ii==1; tmp1=~isempty(find(lon(:)<0))|~isempty(find(lon(:)>360)); |
| 95 |
if tmp1; fprintf('problem in longitude interp\n'); return; end; |
| 96 |
end; |
| 97 |
|
| 98 |
%2) meridional direction: |
| 99 |
tmpB=nanmean2flds(tmpC(:,1:end-1),tmpC(:,2:end),extendNaN); |
| 100 |
tmpA=ones(size(tmpC,1),size(tmpC,2)*2-1); |
| 101 |
tmpA(:,1:2:end)=tmpC; |
| 102 |
tmpA(:,2:2:end-1)=tmpB; |
| 103 |
|
| 104 |
%3) store field: |
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if ii==1; lonOut=tmpA; |
| 106 |
elseif ii==2; latOut=tmpA; |
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elseif ii==3; obsOut=tmpA; |
| 108 |
end; |
| 109 |
end; |
| 110 |
|
| 111 |
%fix potential truncation errors: |
| 112 |
lonOut(lonOut<0)=0; lonOut(lonOut>360)=360; |
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|
| 114 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 115 |
|
| 116 |
function [fld]=nanmean2flds(fld1,fld2,extendNaN); |
| 117 |
%object: compute the average of two fields, accounting for NaNs |
| 118 |
%inputs: fld1 and fld2 are the two fields |
| 119 |
% if extendNaN==1 the result is NaN if either fld1 or fld2 is NaN. |
| 120 |
% Otherwise the result is real if either fld1 or fld2 is real. |
| 121 |
|
| 122 |
if extendNaN==1; |
| 123 |
fld=(fld1+fld2)/2; |
| 124 |
else; |
| 125 |
msk1=~isnan(fld1); fld1(isnan(fld1))=0; |
| 126 |
msk2=~isnan(fld2); fld2(isnan(fld2))=0; |
| 127 |
fld=fld1+fld2; |
| 128 |
msk=msk1+msk2; |
| 129 |
msk(msk==0)=NaN; |
| 130 |
fld=fld./msk; |
| 131 |
end; |
| 132 |
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