中国第三次北极科学考察走航路线上空黑碳气溶胶的观测研究

The observational study of black carbon aerosol over the cruise during the Third National Arctic Research Expedition of China

2008年7月至9月,中国第3次北极科学考察期间,在走航路线上利用黑碳仪对黄海-日本海-鄂霍次克海-西北太平洋-白令海-楚科奇海-加拿大海盆等海区上的黑碳气溶胶浓度进行连续观测,最北观测位置达85°21.3′N。观测结果显示,北冰洋是全航线黑碳浓度最低的海区,平均浓度为（5.3±3.7）ng/m3;在70°N以北的海区范围内黑碳浓度纬向梯度分布不显著。后向气流轨迹的分析显示,夏季期间环北冰洋陆地向北冰洋的输送作用很弱,是北冰洋海区内大气黑碳浓度较低、变化幅度较小、纬向分布不明显的主要原因。日本海、黄海海区的黑碳浓度比较接近,也是整个航线各海区中最高的。7月份去程期间,这两个海区的黑碳浓度均为140~160 ng/m3;9月回程期间为400~500 ng/m3,约为7月份的3倍。对不同海区黑碳浓度差异的分析以及后向气流轨迹的分析均显示,陆源输送是影响海洋大气中黑碳气溶胶浓度的关键因素。

Aerosol black carbon concentration measured at deck level on board the R/V ＂Xuelong＂,with an in-situ aethalometer,during the cruise of the Third National Arctic Research Expedition of China from 12 July to 22 September,2008.The cruise starts and ends at Shanghai,at the northern most point of 85°13.57′N.The result shows that the surface concentration of black carbon in the Arctic Ocean is the lowest throughout the course,with the mean of（5.3±3.7）ng/m3.There is little meridional gradient of black carbon concentration observed in the Arctic Ocean north of 70°N.Back trajectory analysis indicates that the transportation from low latitude to the Arctic Ocean north of 70°N in summer results not only in low surface concentrations of black carbon,but also in a small variation and a very weak meridional gradient.The black carbon concentrations in surfaces of Huanghai Sea and the Sea of Japan are very close each other in both July and September.The black carbon concentration in September is in range of 400~500 ng/m3,which is 3 times of that in July,140~160 ng/m3.The terrigencus transport from the northeast Asia land and Alaska is a crucial element to influence the level of black carbon concentration in the ocean.