How do I visualize or represent values by its color, using contourf ?

Hello everyone, I am trying to plot a color changing 'bar' like diagram. For example, at time t = 1, y=[1 2 3 4 5 6], z=[150 160 170 180 180 160], at time t = 2, y=[1 5 6 7 8 9], z=[140 120 110 100 90 80]. I want to get a 'rainbow' like plot, with x-axis being the time and y-axis being the y values (location), at each y location there is a color index (e.g. a value on the colormap) reflecting the respective z value. So that at higher y value it shows more red and at lower y value it shows more blue on the vertical bar at time t = 1 or t = 2. Hence a gradual change of 'rainbow' colors indicates the change of z values at y location at each time respectively.

At the moment, I use scatter(X,Y,30, Z,'s','filled'). Any better suggestion ?

Thank you very much.

Kind Regards, Jeff