( ( Weather systems ) ( essentially ( ( ( do not ) ( penetrate ( into ( ( ( the stratosphere ) , ) ( which ( is ( ( the layer ) ( above ( the troposphere ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NNP Weather) (NNS systems)) (ADVP (RB essentially)) (VP (VBP do) (RB not) (VP (VB penetrate) (PP (IN into) (NP (NP (DT the) (NN stratosphere)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN layer)) (PP (IN above) (NP (DT the) (NNP troposphere))))))))))) (. .)))
Weather systems essentially do not penetrate into the stratosphere, which is the layer above the troposphere.
(ROOT (S (NP (DT The) (NN stratosphere)) (VP (VBZ is) (NP (NP (DT the) (NN layer)) (PP (IN above) (NP (DT the) (NNP troposphere))))) (. .)))