In situ observations of volcanic ash clouds from the FAAM aircraft during the eruption of Eyjafjallajökull in 2010
In situ observations of volcanic ash clouds from the FAAM aircraft during the eruption of Eyjafjallajökull in 2010
复制标题
DOI：
10.1029/2011jd016760
复制
发表时间：
2012-10
影响因子：
--
通讯作者：
B. Johnson;K. Turnbull;P. Brown;R. Burgess;J. Dorsey;A. Baran;H. Webster;J. Haywood;R. Cotton;Z. Ulanowski;E. Hesse;A. Woolley;P. Rosenberg;Metals Office
中科院分区：
文献类型：
--
作者：
B. Johnson;K. Turnbull;P. Brown;R. Burgess;J. Dorsey;A. Baran;H. Webster;J. Haywood;R. Cotton;Z. Ulanowski;E. Hesse;A. Woolley;P. Rosenberg;Metals Office
[1]在2010年4月至5月期间，英国空中大气测量设施（FAAM）的BAe-146飞机飞行了12次，目标是英国周围的火山灰云。飞机在2-8公里高度之间观测到了火山灰层，根据云和气溶胶分光仪的估计，火山灰的峰值质量浓度通常在200-2000微克/立方米之间。2010年5月14日，在苏格兰上空观测到2000-5000微克/立方米的峰值，但由于可能受到冰的污染，存在相当大的不确定性。灰云中的气溶胶粒径分布显示出与硫酸和/或硫酸盐有关的细模式（0.1-0.6 μm）和与灰有关的粗模式（0.6-35 μm）。灰烬质量主要由尺寸范围为1-10 μm（体积当量直径）的颗粒组成，峰值通常在3-5μm左右。SID-2 H（小型冰探测器）探测器的电子显微镜图像和散射模式显示了火山灰颗粒的高度不规则形状。火山灰云还伴随着SO2浓度的升高（10-100 ppbv），强烈的气溶胶散射（50-500 × 10−6 m−1），以及3波长浊度计的低埃指数（-0.5至0.4）。基于CAS粒度分布的粗模质量比气溶胶消光系数（kext）为0.45-1.06 m2/g。建议从这次喷发的远端灰云（下风向约1000公里）的代表性值为0.6 m2/g。
[1] During April–May 2010 the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft flew 12 flights targeting volcanic ash clouds around the UK. The aircraft observed ash layers between altitudes of 2–8 km with peak mass concentrations typically between 200–2000μg/m3, as estimated from a Cloud and Aerosol Spectrometer (CAS). A peak value of 2000–5000 μg/m3 was observed over Scotland on 14 May 2010, although with considerable uncertainty due to the possible contamination by ice. Aerosol size distributions within ash clouds showed a fine mode (0.1–0.6 μm) associated with sulphuric acid and/or sulphate, and a coarse mode (0.6–35 μm) associated with ash. The ash mass was dominated by particles in the size range 1–10 μm (volume-equivalent diameter), with a peak typically around 3–5μm. Electron-microscope images and scattering patterns from the SID-2H (Small Ice Detector) probe showed the highly irregular shape of the ash particles. Ash clouds were also accompanied by elevated levels of SO2 (10–100 ppbv), strong aerosol scattering (50–500 × 10−6 m−1), and low Angstrom exponents (−0.5 to 0.4) from the 3-wavelength nephelometer. Coarse-mode mass specific aerosol extinction coefficients (kext), based on the CAS size distribution varied from 0.45–1.06 m2/g. A representative value of 0.6 m2/g is suggested for distal ash clouds (∼1000 km downwind) from this eruption.