title: How to customize the colorbar in python?
body: <p>Using this code, I don't know how to customize the colorbar. The colormaps on this <a href="http://matplotlib.org/users/colormaps.html" rel="nofollow noreferrer">webiste</a> can't satisfy me. </p>
  
  <pre><code>shade = m.contourf(Lon,Lat,TBB,np.arange(-90, -20, 10),extend='both',cmap=plt.cm.get_cmap('jet'))       
  m.colorbar(shade)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/QrwDU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QrwDU.png" alt="my_colorbar"></a></p>
  
  <p>I want to draw a picture like this with obvious colorbar. So, what should I do?
       <a href="https://i.stack.imgur.com/cQ0Ve.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cQ0Ve.jpg" alt="colorbar"></a></p>