南极大陆沿岸地面臭氧损耗事件的研究

A study on surface ozone depletion epiodes over the Antarctic coast

利用南极大陆沿岸中山站2008—2013年的地面臭氧连续观测数据和相关资料,对地面臭氧损耗事件(ODE)进行研究。结果显示,春季南极中山站常发生臭氧损耗事件。在该事件发生期间,气象要素有明显的突变过程,包括气温明显下降,风向由偏东风转变为偏北风,风速随之下降。来自海冰区的偏北风增多,风速很小,使臭氧浓度维持在较低水平。地面臭氧损耗事件主要与南极沿岸海冰区的活性溴(BrO)浓度有关。春季南极大陆沿岸海冰冻融过程中形成的冰间水道和冰间湖,在低温的作用下会再次冻结,形成薄冰和霜花。卫星资料能够观测到薄冰区释放的活化海盐溴高浓度区,活性溴与臭氧发生化学反应形成地面臭氧损耗事件。臭氧损耗现象是在未受到人为影响的自然状态下发生的,与中高纬度地区光化学反应导致臭氧消耗有所不同。

The present study on the Antarctic ozone depletion episodes （ODEs） is based on surface ozone records observed at Zhongshan Station in the Antarctic coast and related data during 2008 - 2013. Results show that ODEs frequently occurred in the spring at Zhongshan Station in the Antarctica. During ODEs, there existed abrupt changes in meteorological condition, in- cluding air temperature decrease, wind direction change from easterly to northerly, and wind speed decrease. More northerly winds with lower speeds from sea ice area caused the ozone concentration to maintain at a low level. The occurrence of ODE was mainly related to reactive bromine （BrO） concentration in the sea ice area. In the spring, open leads and polynyas are easily formed during the freezing and thawing processes of sea ice, when young ice and frost flowers are created by cold air sliding on the Antarctic coast. Satellite remote sensing has monitored high concentrations of active bromine derived from sea salt release in young ice areas. The reactive bromine reacts with ozone, leading to ODEs. The phenomenon occurs under natural condition without any anthropic pollution, and thus is different from ozone depletion caused by photochemical reaction in the mid and high latitudes.