地球空氣沙塵含量比100年前增加一倍

If the house seems dustier than it used to be, it may not be a reflection on your housekeeping skills. The amount of dust in the Earth's atmosphere has doubled over the last century, according to a new study. And the increase could be a contributing factor to climate and ecology changes around the world。

如果屋子裏灰塵越來越多，原因可能並不是你放鬆了家裏的清潔工作。因爲根據一項最新的研究顯示，在過去的一個世紀中，地球大氣層中的沙塵含量已經上升了一倍。而這種變化有可能對全球氣候和生態環境產生影響。

To measure fluctuations in desert dust over the last century, American researchers collected existing data from ice cores, lake sediment and coral, each of which contains information about past concentrations of desert dust in the region. They then linked each sample with its likely source region and calculated the rate of dust deposition over time。

爲了測量過去一個世紀以來沙塵的變化情況，研究小組收集了現有的冰心、湖牀沉積物以及珊瑚蟲堆積的檢驗數據，這些樣品中都包含着過去數百年來相關地區的沙塵變化信息。之後研究人員通過沙塵樣本找尋到其對應來源地，並計算這些沙塵隨時間積聚的速率。

Applying components of a computer modeling system known as the Community Climate System Model, the researchers reconstructed the influence of desert dust on temperature, precipitation, ocean iron deposition and terrestrial carbon uptake over time. They found that regional changes in temperature and precipitation caused a global reduction in terrestrial carbon uptake of six parts per million (ppm) over the 20th century while dust deposited in oceans increased carbon uptake by six percent。

藉助一種新型計算機模型“氣候系統耦合模式”(CCSM)，科研人員重建了沙塵對溫度、降水、海洋鐵元素沉積以及陸地碳吸收速率的影響。他們發現，由於地區性溫度和降水的變化，整個20世紀全球陸地碳吸收量下降百萬分之六，而由於海洋塵埃沉降量的增加，同期海洋地區對碳的吸收量增加了6%。

"Now we finally have some information on how the desert dust is fluctuating. This has a really big impact for the understanding of climate sensitivity," said Natalie Mahowald, professor of earth and atmospheric sciences。

“現在我們終於有了一些關於大氣中沙漠塵埃量變化的信息。這將大大有助於研究氣候系統的敏感性，”地球和大氣科學教授娜塔莉 馬宏瓦爾德說道。