Transport of aerosol to the Arctic: analysis of CALIOP and French aircraft data during the spring 2008 POLARCAT campaign
Transport of aerosol to the Arctic: analysis of CALIOP and French aircraft data during the spring 2008 POLARCAT campaign
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DOI：
10.5194/acp-14-8235-2014
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发表时间：
2014-08
影响因子：
6.3
通讯作者：
G. Ancellet;J. Pelon;Y. Blanchard;B. Quennehen;A. Bazureau;K. Law;A. Schwarzenboeck
中科院分区：
文献类型：
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作者：
G. Ancellet;J. Pelon;Y. Blanchard;B. Quennehen;A. Bazureau;K. Law;A. Schwarzenboeck
抽象的。本文报告了在利用飞机、遥感、地面测量和模型、气候、化学、气溶胶和传输进行极地研究活动期间进行的激光雷达和实地观测的统计数据，这些数据是利用2008年3月30日至4月11日在斯瓦尔巴群岛和斯堪的纳维亚之间进行的每日空中测量来表征北方欧洲上空气溶胶特性的。结果表明，在此期间，在对流层中观察到相当多的气溶胶层，在532 nm处的后向散射比为1.2（1.5低于2公里，1.2之间的5和7公里和之间的最小值）。经过仔细的校准分析后，使用多光谱后向散射和去偏振机载激光雷达测量确定了它们的来源。运输分析和现场和机载激光雷达观测之间的比较也提供了这种识别的质量进行评估。与星载正交偏振云-气溶胶激光雷达（CALIOP）的1级后向散射观测进行了比较，以在统计基础上将CALIOP多光谱观测调整为机载观测。CALIOP日间1064 nm信号的重新校准导致其值降低约30%，可能与使用3.0版校准程序有关。即使532 nm散射比偏低（−8%），也没有在532 nm处进行重新校准，因为在空中和CALIOP观测之间的空气质量采样也有显着差异。1064 nm信号的重新校准或532 nm信号中-5%负偏差的校正都可以改善该活动预期的CALIOP气溶胶颜色比。第一个假设在这项工作中得到了保留。在欧洲北极地区进行的区域分析作为一项试验，强调了CALIOP星载激光雷达利用红外和去偏振观测进一步监测北极上空气溶胶层深入特性的潜力。CALIOP 2008年4月的气溶胶后向散射的全球分布揭示了两个在2公里以下具有较大后向散射的区域：格陵兰和挪威之间的北方大西洋和北方西伯利亚。源区之间的气溶胶颜色比增加，在北纬70°以上纬度的观测结果与气溶胶一旦输送到北极后尺寸的增加相一致。对流层中部气溶胶光学特性的分布支持中纬度和北极之间已知的主要传输路径。
Abstract. Lidar and in situ observations performed during the Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, Climate, Chemistry, Aerosols and Transport (POLARCAT) campaign are reported here in terms of statistics to characterize aerosol properties over northern Europe using daily airborne measurements conducted between Svalbard and Scandinavia from 30 March to 11 April 2008. It is shown that during this period a rather large number of aerosol layers was observed in the troposphere, with a backscatter ratio at 532 nm of 1.2 (1.5 below 2 km, 1.2 between 5 and 7 km and a minimum in between). Their sources were identified using multispectral backscatter and depolarization airborne lidar measurements after careful calibration analysis. Transport analysis and comparisons between in situ and airborne lidar observations are also provided to assess the quality of this identification. Comparison with level 1 backscatter observations of the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) were carried out to adjust CALIOP multispectral observations to airborne observations on a statistical basis. Recalibration for CALIOP daytime 1064 nm signals leads to a decrease of their values by about 30%, possibly related to the use of the version 3.0 calibration procedure. No recalibration is made at 532 nm even though 532 nm scattering ratios appear to be biased low (−8%) because there are also significant differences in air mass sampling between airborne and CALIOP observations. Recalibration of the 1064 nm signal or correction of −5% negative bias in the 532 nm signal both could improve the CALIOP aerosol colour ratio expected for this campaign. The first hypothesis was retained in this work. Regional analyses in the European Arctic performed as a test emphasize the potential of the CALIOP spaceborne lidar for further monitoring in-depth properties of the aerosol layers over Arctic using infrared and depolarization observations. The CALIOP April 2008 global distribution of the aerosol backscatter reveal two regions with large backscatter below 2 km: the northern Atlantic between Greenland and Norway, and northern Siberia. The aerosol colour ratio increases between the source regions and the observations at latitudes above 70° N are consistent with a growth of the aerosol size once transported to the Arctic. The distribution of the aerosol optical properties in the mid-troposphere supports the known main transport pathways between the mid-latitudes and the Arctic.