• 关键词：黑碳气溶胶  气象因素  日变化  来源解析  乌鲁木齐河源区

• 基金项目：国家自然科学基金（No.41471058）；中科院重点部署项目（No.KJZD-EW-G03-04）

• 张昕
• 西北师范大学地理与环境科学学院, 兰州 730070

• 李忠勤
• 1. 西北师范大学地理与环境科学学院, 兰州 730070;2. 中国科学院西北生态环境资源研究院, 冰冻圈国家重点实验室, 兰州 730000

• 明镜
• 马克斯·普朗克化学研究所, 德国美因茨 55128

• 王飞腾
• 中国科学院西北生态环境资源研究院, 冰冻圈国家重点实验室, 兰州 730000

• 摘要：利用七波段黑碳仪对2016年8月—2017年7月乌鲁木齐河源区大气中黑碳气溶胶进行了实时监测，并结合同时期气象资料对该区域黑碳气溶胶浓度变化特征、影响因子和可能来源进行了分析.结果表明，观测期间乌鲁木齐河源区黑碳浓度在102~1525 ng·m^-3之间变化，均值为520 ng·m^-3.春季、夏季、秋季和冬季的浓度分别为425、536、686和427 ng·m^-3，呈秋季最高，夏季次之，冬、春季低的季节变化特点.日内变化具有明显的双峰双谷特征，在当地时间8：00—9：00（与北京时间的时差为2小时，即为北京时间10：00—11：00，下同）和16：00—19：00有两个明显的峰值，可能与当地的排放和气象因素有关.乌鲁木齐河源区黑碳的本底浓度在春季、夏季和秋季分别为253、271和290 ng·m^-3，而冬季黑碳的本底浓度仅为162 ng·m^-3.与其他偏远地区相比，乌鲁木齐河源区因受较多排放源影响，黑碳浓度本底值较高.黑碳气溶胶浓度与气象因素相关性显著，当风速小于2 m·s^-1时，黑碳的平均浓度明显偏高，当相对湿度大于55%时，黑碳浓度明显偏低.由浓度权重轨迹分析和波长吸收指数（AAE）可知，乌鲁木齐河源区的黑碳浓度，除了受本地化石燃料燃烧和生物质燃烧排放的影响以外，还可能受到中亚地区远距离传输的影响.

• Abstract：Based on one year real-time measurements of seven-wavelength aethalometer and combined with meteorological data during August 2016—July 2017 at the headwater of Urumqi River, the change characteristics, influencing factors and potential sources of black carbon aerosol have been analyzed. The results showed that daily BC concentration during the studied period was 520 ng·m^-3, fluctuating in the range of 102~1525 ng·m^-3. The BC concentration was 425, 536, 686 and 427 ng·m^-3 in spring, summer, autumn and winter. Seasonal BC concentrations were highest in autumn, followed by summer and low in winter and spring. The two peaks in diurnal variations of BC were observed during morning between 8:00 and 9:00 local time (UTC+6) and in the evening around 16:00—19:00 local time, which is strongly related to the local emission sources, and meteorological factors. The BC background concentration was 253, 271, 290 and 162 ng·m^-3 in the four seasons. By the influence of more emission sources, the BC concentrations at the headwater of Urumqi River are larger than the other remote areas. There was a strong correlation between BC concentration and meteorological factors. The higher BC concentration was more associated with the winds smaller than 2 m·s^-1. Meanwhile, the lower BC concentration were more associated with the relative humidity large than 55%. The concentration weighted trajectory (CWT) analysis and AAE showed long-distance from Central Asia could be important contributors to BC concentrations at the headwater of Urumqi River, same as fossil fuel and biomass burning sources from nearby.

• Key words：black carbon aerosol  meteorological factor  diurnal variation  source apportionment  headwater of Urumqi River

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