中国第四次北极科考航线上黑碳和臭氧的变化特征

利用2010年7月1日至9月20日中国第四次北极科学考察的大气成分在线观测资料,对考察航线上黑碳气溶胶(BC)、臭氧(O3)和B波段紫外辐射(UVB)的分布特征进行了分析.结果显示,这些要素总体上随纬度的增加而递减,其最大值出现在我国东部海域,最低值出现在北冰洋.进入白令海后,BC浓度变化相对平稳,白令海和北冰洋的BC平均浓度分别为15.6ng·m-3和10.5ng·m-3.白令海的平均O3体积分数比北冰洋高,分别为18.9×10-9和15.7×10-9.但在75°N以北海区O3体积分数有所升高,在80°N以北达到17.0×10-9,这一现象可能与海冰密集度和冰上光化学过程有关.UVB辐照度在中低纬地区有显著的日变化,由于在北冰洋航行期间处于极昼期,其变化幅度较小.UVB受天气影响明显,尤其是遇上气旋的阴雨天气,UVB强度较弱.

Variation characteristics of black carbon and ozone over the cruise during the Fourth Chinese National Arctic Research Expedition

Based on the observations of the atmospheric composition on the voyage route during the Fourth Chinese National Arctic Research Expedition from July 1 to September 20, 2010, the distribution characteristics of black carbon (BC), tropospheric ozone (O₃) and ultraviolet radiation (UVB) are presented. The results show that BC,O₃ and UVB decrease with increasing latitude in general, and the maxima are in the East China Sea and the minima are in the Arctic Ocean. BC concentrations vary stably after entering the Bering Sea. The averages in Bering Sea and the Arctic Ocean are 15.6 ng·m^-3 and 10.5 ng·m^-3, respectively. The average of O₃ concentrations in Bering Sea is larger than that in the Arctic Ocean and the averages over the two areas are 18.9×10^-9 and 15.7×10^-9, respectively. However, O₃ concentrations increase in the north of 75°N area and reach 17.0×10^-9 in the north of 80°N. It's possible that this phenomenon is related to the sea ice density and photochemical processes. UVB has a clear diurnal cycle in the middle and low latitudes. Its amplitude is small with weak intensity in the Arctic Ocean due to the polar day effect during the cruise. UVB is affected clearly by weather, and is especially lower during cloudy and rainy day associated with a cyclone.