Table 2. Description of Model Runs in Sensitivity Studies	

Model Run	Description

Standard model 	offline version of the 2-D model using the parameterized QBO circulation, annual cycle in the temperature field

Experiment A	only the QBO-AB signal kept in the transport fields, no annual cycle in the chemistry

Experiment B	only the annual cycle and QBO kept in the transport fields, no annual cycle in the chemistry

Experiment C	only the QBO signal kept in the transport fields, annual cycle in the chemistry