Time series of black carbon aerosol measurements from Neumayer Station, 1999-2011

Continuous black carbon (BC) observations were conducted from 1999 through 2009 by an Aethalometer (AE10) and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP) at Neumayer Station (NM) under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng/m**3) compared to the AE10 results (1.6 ± 2.1 ng/m**3). Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of w550 = 0.992 ± 0.0090 (median: 0.994) at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

1999年至2009年，研究人员在严格的污染控制条件下，使用黑碳仪（Aethalometer, AE10）在诺伊迈尔站（Neumayer Station, NM）开展连续黑碳（Black Carbon, BC）观测；2006年至2011年则采用多角吸收光度计（Multi-Angle Absorption Photometer, MAAP）进行同期观测。结合各自的观测时段来看，MAAP测得的BC浓度（中位数±标准差：2.1±2.0 ng/m³）略高于AE10的观测结果（1.6±2.1 ng/m³）。无论是AE10还是MAAP的数据集，均未检测到显著的长期变化趋势。两种仪器均观测到显著的季节变化特征：每年存在一个主要的浓度峰值时段（10月至11月）与一个谷值时段（4月）；MAAP与AE10数据的峰谷比分别为4.5/1.6=3.8与2.7/0.64=4.2，二者结果一致。偶尔还会在1月/2月出现一个次要的夏季峰值。为评估BC对诺伊迈尔站气溶胶光学特性的影响，本研究结合积分浊度计（integrating nephelometer）测得的粒子散射系数，对BC数据集开展了分析。在550 nm波长下，测得的平均单次散射反照率（single scattering albedo）w550为0.992±0.0090（中位数为0.994），数值分布范围为0.95至1.0。