摘要
酸性气体成分（如ＮＯ－３）的强挥发性导致其在雪面沉降后，具有沉积后气／雪交换作用，即其在表层雪内是“可逆”沉降的。通过比较东南极内陆雪坑的ＮＯ－３剖面和乌鲁木齐河源１号冰川表层雪内ＮＯ－３的浓度变化，认为沉积后气／雪交换作用在东南极内陆较显著，而在乌鲁木齐河源１号冰川则不然。表层雪内ＮＯ－３存在方式的不同和沉降机制的差异应是导致两地ＮＯ－３沉积后过程差异的原因所在。
Acidic species, such as Nitrate, in polar snow and firn layers are “reversibly” deposited, and are sufficiently volatile to undergo significant post depositional exchange between snow/firn and the atmosphere. Through comparison of the snowpit and snowpack nitrate concentrations from central East Antarctica and the headwater of Urumchi River, we conclude that the nitrate peaks in the uppermost surface snow layers in central Antarctica are not related to an atmospheric signal and must account for post depositional effects. Such effects, however, are not found in the surface snowpack nitrate profiles from the headwater of Urumchi River. Two reasons may account for the post depositional difference. At first, nitrate in the polar snow and firn layers appears to be hydrated ion, which can be taken up by the atmosphere, while at the headwater of Urumqi River mainly as mineral ion, which assembles the behavior of aerosol derived species that are “irreversibly” deposited and do not undergo significant post depositional exchange with the atmosphere. Secondly, the chemical features of the snow and ice on the Antarctica are mainly determined by wet deposition, to the contrary, dry deposition is more significant at the headwater of Urumqi River than that on the East Antarctic Plateau.
出处
《极地研究》
CAS
CSCD
1999年第2期81-87,共7页
Chinese Journal of Polar Research
基金
国家自然科学基金
中国科学院95重大项目
攀登计划预选项目
中国科学院天山冰川观测试验站基金
