For each 3D var, there are 5 dimensions including: 
Experiment, QBO_Phase, Ensemble, time, lev, lat, lon
The "Experiment" dimension contains 3 experiments:
PreCtrl, Ctrl, Sensitivity(the one with QBO phase imposed on the selected uwnd/temp/both)
The "QBO_Phase" dimension includes 4 QBO phases: 
QBOE, QBOW, sQBOE, sQBOW 
Note that the "QBO_Phase" is only valid for sensitivity experiment, while for PreCtrl and Ctrl experiment, there are no QBO signals imposed.
Therefore, please ignore the "QBO_Phase" dimension name and use only the 1st element of the "QBO_Phase" dimension for PreCtrl and Ctrl experiment where the outputs of these two experiments are stored.
If you have any questions for the dataset, please contact Kai Huang (khuang8_at_gmu_dot_edu).
Thanks!