How can I interpolate a pressure vector to the surface?

I am working with a pressure vector whose coordinates are between [10,1000] in hPa with 32 pressure values and it is defined between 20ºN-50ºN and 180ºW-180ºE with a resolution of 1º, but now I need to interpolate it to the surface for each latitude and longitude to have a value for the surface pressure in each grid point. How can I do it?

Thnak you so much

Answer 1

[Youssef Khmou]

hi,

You can use the function interp2 like in the demo ( type doc interp2) :

[X,Y] = meshgrid(-3:.25:3);
Z = peaks(X,Y);
[XI,YI] = meshgrid(-3:.125:3);
ZI = interp2(X,Y,Z,XI,YI);
mesh(X,Y,Z), hold, mesh(XI,YI,ZI+15)
hold off
axis([-3 3 -3 3 -5 20])

[Francis]

But I have the problem that my arrays aren´t of the same size and the grid pressure points aren´t separate in the same way, I´m confuse.

[Youssef Khmou]

ok can you post the dimensions of all your variables, we can reshape them ...

Answer 2

[Andrei Bobrov]

lon = randi([-180,180],32,1);
lat = randi([20,50],32,1);
P = randi([10,1000],32,1);    % your data

F = scatteredInterpolant(lat,lon,P,'natural','linear');

[xq,yq] = ndgrid(20:50, -180:179);
pv = F(xq,yq);
figure
mesh(xq,yq,pv);
hold on
plot3(lat,lon,P,'o');

please read about function scatteredInterpolant.

ADD

Try use griddata:

lon = randi([-180,180],32,1);
lat = randi([20,50],32,1);
P = randi([10,1000],32,1);    % your data

[xq,yq] = ndgrid(20:50, -180:179);
vq = griddata(lat,lon,P,xq,yq,'cubic');

figure
mesh(xq,yq,vq);
hold on
plot3(lat,lon,P,'o');

[Youssef Khmou]

Andrei, which version contains the function scatteredInterpolant ?

[Andrei Bobrov]

R2013a (8.01)

[Francis]

Thanks so much for your answer, but I have version R2012a, how can I do the same but in this version?

Thanks

[Andrei Bobrov]

try use function TriScatteredInterp

[Andrei Bobrov]

See ADD part in this answer.