中文摘要：

采用SLIMCAT化学传输模式以及再分析资料,对比分析了1997和2011年北极地区平流层臭氧异常偏低事件及其成因。结果表明,1997和2011年3月北极地区大气臭氧柱总量（TCO）异常值都达到了约-80 DU,并且在30—200 hPa（中下平流层）区域的大气臭氧柱总量异常约占整层大气臭氧柱总量异常的80%。分析表明发生在这两年的极端臭氧偏低事件均可能是由于上一年冬季的拉尼娜事件导致上传的行星波减少,使得北极极涡加强,平流层温度异常偏低,生成了更多极地云,引起更强的臭氧化学损耗导致的。对比这两年的大气臭氧柱总量变化发现,2011年的柱总量减少得更快。2011年北极地区上对流层下平流层（UTLS）区域臭氧下降要明显强于1997年,其主要原因应该是2010—2011冬季的拉尼娜活动更强,北太平洋海温更高,进一步减弱阿留申低压和平流层波活动。这导致2011年极涡温度异常偏低更强烈,形成了更多的极地平流层云甚至出现了第二类极地平流层云,最终加速该年春季的臭氧化学损耗引起的。

英文摘要：

Using a chemistry transport model （SLIMCAT） and reanalysis data, this study investigates the extremely low ozone events in 1997 and 2011 in the Arctic stratosphere. The analysis reveals that, the magnitudes of total column ozone （TCO） a- nomalies over the Arctic in 1997 and 2011 both could be up to about - 80 DU and the ozone decreases between 200 hPa and 30 hPa accounted for about 80% of the TCO anomalies. Our analysis suggests that the two extremely low Arctic TCO events were possibly related to La Nina activity, which resulted in a stronger Arctic polar vortex, a lower stratospheric temperature, more polar clouds, and eventually more ozone chemical loss. Furthermore, since the positive sea surface temperature anomalies in the North Pacific in 2011 led to a lower Aleutian low, a weaker troposphere wave forcing, a colder Arctic vortex and more type Ⅱ PSCs , the ozone chemical loss in the Arctic UTLS region was accelerated in 2011. A comparison of the ozone anoma lies in different layers between 1997 and 2011 indicates that the ozone decrease in the Arctic UTLS region in 2011 was much larger than that in 1997.