There is a DBC view available named dbc.indexconstraints. You can use this view to get all the partitioned table names. The partitioned tables have a constrainttype of 'Q'. There is also an attribute constrainttext which contains original partition expression. You can use like operator to find the date partitioned tables.
SELECT * FROM dbc.indexconstraints
WHERE Constrainttype = 'Q' AND ConstraintText like '%%';