Jia-Lin Lin (in collaboration with Brian Mapes) discussed about the 
Madden-Julian Oscillation (MJO) problem in climate models. The MJO is 
the dominant intraseasonal mode of convection and circulation in the 
tropics, but is poorly simulated in current GCMs. Because the MJO 
problem is a common problem in many GCMs, their hypothesis is: The MJO 
problem is caused by some missing physics in current GCMs. Based on 
the MJO theories and their diagnostic results, Lin discussed about 
three missing physical processes that are likely important for the 
MJO: (1) Shear effects on anvil clouds and cloud radiative forcing; 
(2) Convective momentum transport by shallow convection; and (3) 
Stratiform precipitation and stratiform heating profile. It would be 
interesting to install these missing physics into GCMs and test their 
impacts on the MJO simulation.