Le 30 novembre 2016, 04:56 dans Humeurs • 0
Hurricane breeding grounds (发源地) in the Atlantic and Pacific oceans are being warmed by greenhouse gases, probably making hurricanes stronger in coming decades, according to a new study by the Proceedings of the National Academy of Sciences (PNAS).
The scientists used 22 climate models to investigate the possible causes of a rise in sea surface temperatures (SST) of up to 0.67℃ in the Atlantic and Pacific tropics (热带地区) from 1906 to 2005.
Each computer model was run several times to work out how much the SST would have warmed with or without rising levels of greenhouse gases and other pollutants. “We’ve used all the world’s climate models to study the causes of the SST changes in hurricane formation regions,” Santer said.
They found that tiny particulates (微粒) from volcanoes and sulfates (硫酸盐) from industrial plants blocked the sun, and so cooled the oceans. But the effect was overcome by the rise in greenhouse gases, which led to warmer oceans.
“The important conclusion is that the observed SST increases in the regions cannot be explained by natural processes alone,” said Tom Wigley, another researcher of the study, from the Boulder-based National Center for Atmospheric Research (NCAR). “The best explanation for these changes has to include a large human influence.” Also, Wigley warns that global temperatures and SSTs may increase even more rapidly over the next century.
Hurricanes are a complex phenomenon that is influenced by a variety of physical factors, such as SSTs, wind shear (剪应力), water vapor, and atmospheric stability. In the Atlantic and Pacific hurricane formation regions, hurricane intensity is not only determined by the increasing SSTs, which, though, are likely to be one of the most significant influences.
investigate v. to examine something carefully, especially to discover the truth 深入研究
intensity n. the quality of being felt very strongly or having a strong effect强度
True (T) or False (F):
1. In a way, greenhouse gases are blamed for the increasing SST.
2. Any pollutant can be seen as one cause of a rise in SST.
3. In Tom’s opinion, human influence is closely linked to the increasing SST.
4. SSTs are one of physical factors which influence hurricanes.