The news caster pronounces ‘superior’ as /səˈpɪər i ər/. And I can find his pronunciation in the Random House Dictionary. But the other major dictionaries show /suːˈpɪriər/ or /sjuːˈpɪəriə/. So I can’t decide ‘superior’ alone can be pronounced /səˈpɪər i ər/, when it is pronounced by itself not in the sentence?
This is closely related to an earlier question, which I think it would repay you to consult.
What is in play here is varying realizations and transcriptions of a close rounded reduced vowel: a vowel representing a stem <u> which is not only unstressed but 'bleached' of much of its distinctive character. For historical reasons, some dictionaries and phonologists represent this vowel with a schwa /ə/, others with /u/ or /ʊ/. (I find it difficult to believe that anybody has ever pronounced this syllable with /uː/, unless under special circumstances requiring the syllable be unnaturally stressed.) This Wikipedia article tells us the Oxford dictionaries are starting to use a symbol of their own, /ᵿ/, for this sound.
But it's not something anybody but a professional phonologist or phonetician needs to worry about. As long as you pronounce the syllable without stress, nobody will notice whether you say /sə/ or /sʊ/ or even /sɪ/; what people actually hear is the stressed vowels.