How to make a Hovmoller plot?

Hi

I'm trying to make a Hovmoller diagram with latitudes out of the x-axis and the time up of the y-axis. The actual plot is the size of the geopotential height gradient, GHGN.

I have tried the code:

GHGN = (z(:,[80+[-1 0 1]])-z(:,[60+[-1 0 1]]))/(80-60)

figure(6);clf
contourf(latr+[-1 0 1],time,GHGN);
shading flat; colorbar
ylabel('Time (days)')
xlabel('Y distance (km)')

However, I got the error "Matrix dimensions must agree."

How do I get done so I can plot?

My variables have the sizes: latr = 1x181. time = 124x1. GHGN = 360x3. z = 360x181

z is dependent on time.