Characteristics Of Aerosol Black Carbon Over Ny-(?)lsund In The Summer Arctic

Average Arctic temperatures increased at almost twice the global average rate in the past 100 years. Although anthropogenic long-lived greenhouse gases will play a predominant role in radiation forces in weather system, the Black Carbon Aerosol and other short-lived pollutants may be contributing to the accelerated rates of warming observed in this region. Routine ground-level observations of Black Carbon Aerosol by optical absorption were made at the Chinese Arctic Yellow River Station at Ny-?lesund in summer months from 2005 to 2008. In this study, we use Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine the potential source regions of the Black Carbon Aerosol and Ensemble Empirical Mode Decomposition (EEMD) method to investigate the temporal variations. Results indicate that:1 Back ground and median Black Carbon Aerosol concentrations are 7.16ng/m3 and 14.58ng/m3, respectively. A net increase in Black Carbon Aerosol concentration of about 4ng/(m3.y) is observed at Ny-?lesund.2 High Black Carbon Aerosol concentration can be recognized in the sector of SE—NW. When wind speed less than 5m/s, Black Carbon Aerosol concentration increases with wind speed, when wind speed more than 5m/s, Black Carbon Aerosol concentration remains.3 Time series of Black Carbon Aerosol concentration are analyzed using EEMD method. Results reveals that it includes various timescales oscillation . IMF1 is mostly dominated by a component with a period of about 3 hours, which may implies background noise with a period of 6～12 hours. IMF2 indicates the effect of humman avtivity with a period of a half to two days. IMF3 represents a component of local emission. IMF4 is mostly dominated by a component with a character of strong wind, which usually connects with transportation of Atlantic cyclonic and low pressure of main land Europe. IMF5 is the frequency component of Siberia cyclonic activities. IMF6 is mostly dominated by a component with a period of 6～14 days, which implies the frequency of wave train in high latitude.IMF7 and IMF8 are mostly dominated by a longer period of about 20 days, which would be discussed by the longer collected data.4 For data in summer months from 2005 to 2008 at Ny-?lesund, eight potential source areas are identified as having important contributions to Black Carbon Aerosol at this location. There are Atlantic Ocean/North Canada (cluster 1), Atlantic Ocean /North Europe (cluster 2), North Europe /Russia (cluster 3), Central Siberian/Russia (cluster 4), Atlantic ocean/Greenland (cluster 5), Alaska/East Siberian (cluster 6), North Canada/Alaska/Greenland (cluster 7) and Arctic Ocean (cluster 8). Typical clusters are clusters 2,5,6 and 7.43% of the 7-day back trajectories are in Arctic ocean (cluster 8), thus this is the most common flow pattern at Yellow River Station. Only 2% of the trajectories are found in Central Siberian/Russia (cluster 4 ) thus this pattern is the least frequency at Yellow River Station. Meanwhile clusters 4 and 6 are typical clusters with Siberian cyclonic activities, cluster 2 is associated with Atlantic Ocean cyclonic activities.5 There is a positive correlation between NAO index and Black Carbon Aerosol Anomaly in cluster 8. A high NAO-index implies high Black Carbon Aerosol Anomaly. The Yellow River Station at Ny-?lesund is impacted by Black Carbon Aerosol emissions from Alantic ocean, North Europe/Russia, Alaska and some from North Canda.