Interpolate vertically from a 4-D data set

Dear all,

Here's the thing. I have two 4-D data sets of T(longitude,latitude,pressure,time) and w(longitude,latitude,pressure,time) which are temperature and vertical velocity respectively. I intended to interpolate vertical velocity to a specific temperature level (ex：320K), and tried to handle this by scatteredInterpolatant function. However, it took me more than 10 minutes only for making the interpolant. I was wondering if there's a more efficient way to implement this. Here's the code I made for the interpolant:

for t=1:nt
  X     = double(reshape(longitude(:,:,:,t),[],1));
  Y     = double(reshape(latitude(:,:,:,t),[],1));
  Z     = reshape(theta(:,:,:,t),[],1);

    omega = reshape(w(:,:,:,t),[],1);
    F     = scatteredInterpolant(X,Y,Z,omega);
    V     = F(X,Y,Q);
end

Any help would be appreciated.

Sincerely, Charles Tai