地球空气沙尘含量比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。

　　如果屋子里灰尘越来越多，原因可能并不是你放松了家里的清洁工作。因为根据一项最新的研究显示，在过去的一个世纪中，地球大气层中的沙尘含量已经上升了一倍。而这种变化有可能对全球气候和生态环境产生影响。

　　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。

　　为了测量过去一个世纪以来沙尘的变化情况，研究小组收集了现有的冰心、湖床沉积物以及珊瑚虫堆积的检验数据，这些样品中都包含着过去数百年来相关地区的沙尘变化信息。之后研究人员通过沙尘样本找寻到其对应来源地，并计算这些沙尘随时间积聚的速率。

　　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。

　　借助一种新型计算机模型“气候系统耦合模式”(CCSM)，科研人员重建了沙尘对温度、降水、海洋铁元素沉积以及陆地碳吸收速率的影响。他们发现，由于地区性温度和降水的变化，整个20世纪全球陆地碳吸收量下降百万分之六，而由于海洋尘埃沉降量的增加，同期海洋地区对碳的吸收量增加了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。

　　“现在我们终于有了一些关于大气中沙漠尘埃量变化的信息。这将大大有助于研究气候系统的敏感性，”地球和大气科学教授娜塔莉 马宏瓦尔德说道。