function []=fix_masks(ncfile);
% fix the u,v,p masks to match the rho mask
% usage: fix_masks(ncfile);
nc=netcdf(ncfile,'w');
rmask=nc{'mask_rho'}(:);
[umask,vmask,pmask]=uvp_masks(rmask);
nc{'mask_u'}(:)=umask;
nc{'mask_v'}(:)=vmask;
nc{'mask_psi'}(:)=pmask;
close(nc);