What type of clouds are these? I would appreciate some help in identifying these clouds:



This was taken on a commercial plane flying between Hong Kong and Japan on the 31st of March around 2pm.

I tried looking up cloud types but was not too sure. This sort of had two different looks - one being a flat kind of sea, and the other being the smaller, noisier clouds popping up from underneath.

Thanks very much.
Mostly stratocumulus with a scattering of emergent cumulus towers which have been lofted by strong internal convection cells.