A three-dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM-ARCMIP, April 2009
A three-dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM-ARCMIP, April 2009
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DOI：
10.1029/2009jd013605
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发表时间：
2010-07
影响因子：
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通讯作者：
R. Stone;A. Herber;V. Vitale;M. Mazzola;A. Lupi;R. Schnell;E. Dutton;P. Liu;Shao-Meng Li
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文献类型：
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作者：
R. Stone;A. Herber;V. Vitale;M. Mazzola;A. Lupi;R. Schnell;E. Dutton;P. Liu;Shao-Meng Li
[1]北极气候在一定程度上受到大气气溶胶的调节，气溶胶会影响穿过大气的辐射能的分布。气溶胶通过与太阳和地面辐射的相互作用直接影响地表-大气辐射平衡，并通过与云粒子的相互作用间接影响。为了改进对未来气候的预测，需要更好地量化不同类型气溶胶的辐射强迫。2009年4月，中国开展了“泛北极测量与北极区域气候模式比对项目”（PAM-ARCMIP）。这次任务是由德国阿尔弗雷德·韦格纳极地和海洋研究所组织的，使用了他们的研究飞机极地5号。目的是在融冰季节开始之前，获取北极中部地表和大气状况的快照。表征气溶胶是该运动的目标之一。采用标准的太阳光度测量程序来量化气溶胶光学深度AOD，提供气溶胶的三维视图，其中主要是来自人为来源的雾霾。来自机载激光雷达的独立的、原位的粒度分布和光消光测量结果被用来证实利用AOD结果得出的推论。2009年4月，从欧洲到阿拉斯加北极，从亚北极纬度到极地附近，大气呈现不同程度的雾霾，500 nm处的总柱AOD在~ 0.12到~ 0.35之间，与往年相比异常高。雾霾主要来自欧亚工业地区，集中在地表逆温层内部和上方。根据机载激光雷达系统的测量，低水平下的消光也最大，因为低水平下的粒子往往比高水平下的粒子稍大。在所有取样水平均观察到黑碳（烟灰），但与历史记录相比，其浓度处于中低水平。BC在北极附近是最高的，这表明在北极涡旋中有煤烟的积累。尽管独立的激光雷达观测揭示了火山羽流通过的证据，但沿着飞行轨迹观测到的光学厚度的上升气溶胶层很少，这可能是造成4公里以上AOD异常高值的原因。在活动期间，高海拔地区的不透明度增强是由于对流层上层工业污染物的积累，加上2009年3月至4月阿拉斯加Redoubt火山喷发产生的火山气溶胶。据估计，2009年4月北极雾霾的存在使净短波辐照度减少了~ 2 - 5 W m−2，导致地表略有降温。
[1] The Arctic climate is modulated, in part, by atmospheric aerosols that affect the distribution of radiant energy passing through the atmosphere. Aerosols affect the surface-atmosphere radiation balance directly through interactions with solar and terrestrial radiation and indirectly through interactions with cloud particles. Better quantification of the radiative forcing by different types of aerosol is needed to improve predictions of future climate. During April 2009, the airborne campaign Pan-Arctic Measurements and Arctic Regional Climate Model Inter-comparison Project (PAM-ARCMIP) was conducted. The mission was organized by Alfred Wegener Institute for Polar and Marine Research of Germany and utilized their research aircraft, Polar-5. The goal was to obtain a snapshot of surface and atmospheric conditions over the central Arctic prior to the onset of the melt season. Characterizing aerosols was one objective of the campaign. Standard Sun photometric procedures were adopted to quantify aerosol optical depth AOD, providing a three-dimensional view of the aerosol, which was primarily haze from anthropogenic sources. Independent, in situ measurements of particle size distribution and light extinction, derived from airborne lidar, are used to corroborate inferences made using the AOD results. During April 2009, from the European to the Alaskan Arctic, from sub-Arctic latitudes to near the pole, the atmosphere was variably hazy with total column AOD at 500 nm ranging from ∼0.12 to >0.35, values that are anomalously high compared with previous years. The haze, transported primarily from Eurasian industrial regions, was concentrated within and just above the surface-based temperature inversion layer. Extinction, as measured using an onboard lidar system, was also greatest at low levels, where particles tended to be slightly larger than at upper levels. Black carbon (BC) (soot) was observed at all levels sampled, but at moderate to low concentrations compared with historical records. BC was highest near the North Pole, suggesting there had been an accumulation of soot within the Arctic vortex. Few, optically thick elevated aerosol layers were observed along the flight track, although independent lidar observations reveal evidence of the passage of volcanic plumes, which may have contributed to abnormally high values of AOD above 4 km. Enhanced opacity at higher altitudes during the campaign is attributed to an accumulation of industrial pollutants in the upper troposphere in combination with volcanic aerosol resulting from the March–April 2009 eruptions of Mount Redoubt in Alaska. The presence of Arctic haze during April 2009 is estimated to have reduced the net shortwave irradiance by ∼2–5 W m−2, resulting in a slight cooling of the surface.