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标签:南极 气候 变暖
摘要 : 南极半岛经常被作为关于迅速变暖的一个案例研究。

 南极半岛经常被作为关于迅速变暖的一个案例研究。现在,John Turner 及同事发现,二十世纪末期的变暖趋势在相当大程度上减弱了,在二十世纪早期几年,该半岛的气候主要在变冷。该半岛只是南极洲的很小一部分,这些发现并不意味着在南极洲或其他地方存在更普遍的变冷趋势。相反,它们表明,这一地区十年尺度的温度变化并不是主要与全球温度变化的驱动因素相关,而是由该地区大气环流的极端自然内部变化造成的。


Absence of 21st century warming on Antarctic Peninsula consistent with natural variability


Since the 1950s, research stations on the Antarctic Peninsula have recorded some of the largest increases in near-surface air temperature in the Southern Hemisphere1. This warming has contributed to the regional retreat of glaciers2, disintegration of floating ice shelves3 and a ‘greening’ through the expansion in range of various flora4. Several interlinked processes have been suggested as contributing to the warming, including stratospheric ozone depletion5, local sea-ice loss6, an increase in westerly winds5, 7, and changes in the strength and location of low–high-latitude atmospheric teleconnections8, 9. Here we use a stacked temperature record to show an absence of regional warming since the late 1990s. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer. Temperatures have decreased as a consequence of a greater frequency of cold, east-to-southeasterly winds, resulting from more cyclonic conditions in the northern Weddell Sea associated with a strengthening mid-latitude jet. These circulation changes have also increased the advection of sea ice towards the east coast of the peninsula, amplifying their effects. Our findings cover only 1% of the Antarctic continent and emphasize that decadal temperature changes in this region are not primarily associated with the drivers of global temperature change but, rather, reflect the extreme natural internal variability of the regional atmospheric circulation.

来源: Nature 浏览次数:1


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