极地研究 ›› 2011, Vol. 22 ›› Issue (4-English): 253-259.DOI: 10.3724/SP.J.1085.2011.00253
TANG Jie1,2, BIAN Lingen2, YAN Peng1,2, LAI Xin2 & LU Changgui2
摘要:
This paper presents aerosol black carbon (BC) concentration measured at deck level on board the R/V Xuelong cruising over Arctic ocean, with an in-situ Aethalometer, in summer of 2008 and of 2010. The courses of the Third Chinese Arctic Research Expedition (3rd CARE, in August of 2008) and of the Fourth Chinese Arctic Research Expedition (4th CARE, from late July to August of 2010) are within 173oW—143 oW and 178oE—150oW, with the north-most point of 85°25′N and of 88°26′N, respectively. The results showed the surface BC concentration over Arctic Ocean are low throughout the courses, with the mean (±standard error) of 6.0(±4.7)ng?m-3 .for 3rd CARE and 8.4(±7.1)ng?m-3 for 4th CARE. The latitudinal averaged BC concentration varies in the range of 3.0~26.2 ng?m-3 for 3rd CARE and of 4.2~20.5 ng?m-3 for 4th CARE. The latitudinal gradients of BC concentration are observed with lower values in high latitudes, but the gradients are weak in higher latitudes than 75°N. Comparison with the limited measurements by land stations in Arctic region shows that the on-board BC concentration measured in this study is in the same level with the results from Barrow station in Alaska. Back trajectory analysis indicated that the transport from low latitude to Arctic Ocean is weak in summer, due to the “Arctic front”, resulting in not only low surface BC concentration, but also a small latitudinal gradient of BC concentration. However, the obstruct effect of “Arctic front” in summer of 2010, to the transport from the low latitudes, was weak so as that the BC concentration in summer of 2010 was higher than that in summer of 2008, which shows a crucial impact of oscillation of atmospheric circulation pattern on the pollutant transport from low latitudes to Arctic ocean and to the level of BC concentration there.