The point of view in this excerpt is definitely third person, because nouns such as Dorothy, and pronouns such as she are used throughout to indicate third person.
However, if you also need to decide whether it is limited or omniscient, I'd choose limited - because we can only see what she is doing, and not what she is thinking and feeling.
The poem "ode to the west wind" Consists of five sections or what we call "cantos". written in Terza rima (an interlocking three-line scheme). Each of the sections consist of four tercets( set or group of three lines of verses that rhyme together).....(ABA,BCB,CDC,DED). And a rhyming couplet (EE) the poem is written in iambic pentameter(a line or verse with five metrical feet).
