( ( The sun ) ( ( ( is ( especially important ) ) ( as ( ( its ( uneven ( heating distribution ) ) ) ( drives ( weather systems ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (ADJP (RB especially) (JJ important)) (SBAR (IN as) (S (NP (PRP$ its) (JJ uneven) (NN heating) (NN distribution)) (VP (VBZ drives) (NP (NN weather) (NNS systems)))))) (. .)))
The sun is especially important as its uneven heating distribution drives weather systems.
(ROOT (S (NP (NP (NN Uneven) (NN heating)) (PP (IN of) (NP (DT the) (NN atmosphere)))) (VP (VBP form) (NP (NN weather) (NNS patterns))) (. .)))