( ( When ( there ( is ( light precipitation ) ) ) ) ( , ( dust ( ( ( ( stays aloft ) and ) ( is ( ( carried ( to ( the ( ice sheets ) ) ) ) ( with ( the snow ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (EX there)) (VP (VBZ is) (NP (JJ light) (NN precipitation))))) (, ,) (NP (NN dust)) (VP (VP (VBZ stays) (ADVP (RB aloft))) (CC and) (VP (VBZ is) (VP (VBN carried) (PP (TO to) (NP (DT the) (NN ice) (NNS sheets))) (PP (IN with) (NP (DT the) (NN snow)))))) (. .)))
When there is light precipitation, dust stays aloft and is carried to the ice sheets with the snow.
(ROOT (S (NP (NNP Birds)) (VP (VBP need) (NP (DT a) (JJ light-weight) (NN body)) (PP (IN for)) (S (VP (TO to) (VP (VB stay) (ADVP (RB aloft)))))) (. .)))