Heavy Turbulence after takeoff from Shanghai Pudong International Airport!

We have encountered some heavy turbulence after our takeoff from Shangai's Pudong International Airport. You can see it at the end of the video.
Does anyone know what type of maneuver is the pilot doing?
Far as I understand, they leveled up after takeoff, brought the plane down some feet and after that, (unfortunately I didn't record it - we like turbulence but we didn't see this one coming), we heard the pilots disconnecting auto pilot and putting the plane into a steep climb with the engines at full power.
Airline: Spring Airlines