Horizontal and vertical structure of the Eyjafjallajökull ash cloud over the UK: a comparison of airborne lidar observations and simulations
Horizontal and vertical structure of the Eyjafjallajökull ash cloud over the UK: a comparison of airborne lidar observations and simulations
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英国上空埃亚菲亚德拉冰盖火山灰云的水平和垂直结构：机载激光雷达观测与模拟的比较
DOI：
10.5194/acp-12-10145-2012
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发表时间：
2012
影响因子：
6.3
通讯作者：
F. Marenco
中科院分区：
文献类型：
--
作者：
A. Grant;H. Dacre;D. Thomson;F. Marenco
2010年4月至5月期间，冰岛艾雅法拉火山喷发的火山灰云对北欧的航空造成了广泛的干扰。火山喷发的位置和影响使人们获得了大量的火山灰云观测资料，这些资料可用于评估对流层中火山灰远距离传输的模型。英国FAAM（机载大气测量设施）的ba146 -301研究飞机在5月份的几天内飞越了火山灰云。飞机携带一个向下看的激光雷达，通过激光的反向散射探测到灰层。在本研究中，将激光雷达得到的灰浓度与通用大气传输和弥散模式NAME （Nu- merical atmospheric -dispersion modeling Environment）对灰云的模拟进行了比较。将模拟的火山灰云与激光雷达数据进行比较，以确定NAME如何很好地模拟火山灰云的水平和垂直结构。通过比较激光雷达得到的火山灰浓度和从NAME得到的火山灰浓度，可以确定火山喷发时喷出的火山灰中长距离传播的比例，与火山喷出的全部火山灰相比。在进行这些比较时，可以识别和解释模拟火山灰云中可能存在的位置误差。本研究中考虑的激光雷达看到的火山灰层很薄，典型的深度为550-750米。NAME模拟的火山灰云的垂直结构与观测到的火山灰层基本一致，尽管模拟的火山灰云中与观测到的火山灰层相识别的层数大约是观测层深度的两倍。模拟的火山灰云的结构对假设的火山灰排放曲线很敏感。在水平和垂直结构方面，假设喷发发生在喷发柱的顶部，与观测到的喷发柱结构一致，得到了最好的结果。然而，在喷发强度较低的早期，假设火山灰的喷发随高度均匀，可以更好地指导火山灰云的水平和垂直结构。将激光雷达的浓度与NAME的浓度进行比较表明，火山喷发的总质量的2- 5%留在了英国上空的火山灰云中。
During April and May 2010 the ash cloud from the eruption of the Icelandic volcano Eyjafjallaj ¨ okull caused widespread disruption to aviation over northern Europe. The location and impact of the eruption led to a wealth of ob- servations of the ash cloud were being obtained which can be used to assess modelling of the long range transport of ash in the troposphere. The UK FAAM (Facility for Airborne Atmospheric Measurements) BAe-146-301 research aircraft overflew the ash cloud on a number of days during May. The aircraft carries a downward looking lidar which detected the ash layer through the backscatter of the laser light. In this study ash concentrations derived from the lidar are compared with simulations of the ash cloud made with NAME (Nu- merical Atmospheric-dispersion Modelling Environment), a general purpose atmospheric transport and dispersion model. The simulated ash clouds are compared to the lidar data to determine how well NAME simulates the horizontal and ver- tical structure of the ash clouds. Comparison between the ash concentrations derived from the lidar and those from NAME is used to define the fraction of ash emitted in the eruption that is transported over long distances compared to the to- tal emission of tephra. In making these comparisons possible position errors in the simulated ash clouds are identified and accounted for. The ash layers seen by the lidar considered in this study were thin, with typical depths of 550-750 m. The vertical structure of the ash cloud simulated by NAME was generally consistent with the observed ash layers, although the layers in the simulated ash clouds that are identified with observed ash layers are about twice the depth of the observed layers. The structure of the simulated ash clouds were sensitive to the profile of ash emissions that was assumed. In terms of hori- zontal and vertical structure the best results were obtained by assuming that the emission occurred at the top of the erup- tion plume, consistent with the observed structure of eruption plumes. However, early in the period when the intensity of the eruption was low, assuming that the emission of ash was uniform with height gives better guidance on the horizontal and vertical structure of the ash cloud. Comparison of the lidar concentrations with those from NAME show that 2-5 % of the total mass erupted by the vol- cano remained in the ash cloud over the United Kingdom.
2010 年埃亚菲亚德拉冰盖火山灰羽流的机载激光雷达观测
影响因子：
--
作者：
Marenco F
通讯作者：
Marenco F
影响因子：
--
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
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
2010 年埃亚菲亚德拉冰盖喷发远端火山云中火山灰浓度的业务预测
DOI：
10.1029/2011jd016790
发表时间：
2012
期刊：
Atmospheres
影响因子：
--
作者：
Webster H
通讯作者：
Webster H