今天是:?世界海洋日

What are those unusual streaks? Some images of planet Earth show clear bright streaks that follow the paths of ships. Known as ship tracks, these low and narrow bands are caused by the ship’s engine exhaust. Water vapor condenses around small bits of exhaust known as aerosols, which soon grow into floating water drops that efficiently reflect sunlight. Ship tracks were first discovered in 1965 in Earth images taken by NASA’s TIROS satellites. Multiple ship tracks are visible across the featured image that was captured in 2009 over the Pacific Ocean by the MODIS instrument on NASA’s Terra satellite. Inspired by ship-tracks, some scientists have suggested deploying a network of floating buoys in the worlds’ oceans that spray salt-aerosol containing sea-water into the air so that, with the help of the wind, streams of sunlight-reflecting clouds would also form. Why do this? These human-made clouds could reflect so much sunlight they might help fight global warming.

那些不尋常的條紋是什么？地球的某些影像，會(huì)清楚記錄到與船只航路重疊的清晰明亮條紋。這些低懸在海面的狹窄帶紋稱為船舶軌跡，其源頭為船舶引擎的排氣。排氣中的水蒸氣，會(huì)凝結(jié)在廢氣里的微細(xì)氣溶膠周圍，并很快的聚成漂浮的水滴，進(jìn)而高效率的反射陽(yáng)光。船舶軌跡是在1965年，首先發(fā)現(xiàn)于NASA TIROS衛(wèi)星所拍攝的地球影像里。而在2009年，由NASA Terra衛(wèi)星MODIS感測(cè)器攝于太平洋上空的這幅主題影像里，亦可見(jiàn)到多條船舶軌跡。受到這種船軌的啟發(fā)，有科學(xué)家建議在世界各地的海洋里，布署一個(gè)能把含海水的鹽氣溶膠噴到空氣中的浮標(biāo)網(wǎng)絡(luò)，然后在風(fēng)推送下，形成不停反射陽(yáng)光的條狀流云。為什么要這樣做？這種人造云可以反射大量的陽(yáng)光，或許有助于對(duì)抗全球暖化。