( This ( ( ( ( defines ( ( the break ) ( between ( ( ( the mesosphere ) and ) ( the thermosphere ) ) ) ) ) , ) ( where ( temperature ( again ( increases ( with ( increasing altitude ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ defines) (NP (NP (DT the) (NN break)) (PP (IN between) (NP (NP (DT the) (NN mesosphere)) (CC and) (NP (DT the) (NN thermosphere))))) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (NN temperature)) (ADVP (RB again)) (VP (VBZ increases) (PP (IN with) (NP (VBG increasing) (NN altitude))))))) (. .)))
This defines the break between the mesosphere and the thermosphere, where temperature again increases with increasing altitude.
(ROOT (S (PP (IN As) (NP (NN altitude) (NNS rises))) (, ,) (NP (DT the) (NN temperature)) (VP (VBZ increases) (PP (IN in) (NP (DT the) (NN thermosphere)))) (. .)))