he's saying "good morning sunshine" because he is referring to a girl. that girl is referred to as "sunshine" because she is happy, therefore resembling sunshine. when he says "where you rise i gladly follow, just for the chance to stand in your light", he means that he goes with her because she lights up his day, because she has a glow, because she resembles sunshine, BECAUSE SHE IS HAPPY. 0_o so long meaning short, he is talking about a happy girl.
he's saying "good morning sunshine" because he is referring to a girl. that girl is referred to as "sunshine" because she is happy, therefore resembling sunshine. when he says "where you rise i gladly follow, just for the chance to stand in your light", he means that he goes with her because she lights up his day, because she has a glow, because she resembles sunshine, BECAUSE SHE IS HAPPY. 0_o so long meaning short, he is talking about a happy girl.