Volcanic ash layer depth: Processes and mechanisms
Volcanic ash layer depth: Processes and mechanisms
复制标题
DOI：
10.1002/2014gl062454
复制
发表时间：
2015-01
影响因子：
5.2
通讯作者：
H. Dacre;A. Grant;Natalie J. Harvey;David J. Thomson;H. Webster;F. Marenco
中科院分区：
文献类型：
--
作者：
H. Dacre;A. Grant;Natalie J. Harvey;David J. Thomson;H. Webster;F. Marenco
2010年埃亚菲亚德拉火山爆发的持续时间很长，这为测量广泛分散的火山灰云提供了一个独特的机会。欧洲气溶胶研究激光雷达网观测到火山灰层，平均深度为1.2公里，标准差为0.9公里。在本文中，我们评估了英国气象局的数值大气扩散模拟环境（NAME）模拟观测到的灰层的能力，并研究了控制其深度的过程。NAME对远端灰层深度的模拟非常好，平均深度为1.2 km，标准差为0.7 km。决定欧洲上空灰层深度的主要过程是垂直风切变（其作用是减少灰层深度）和垂直湍流混合（其作用是加深灰层）之间的平衡。有趣的是，火山灰颗粒的差异沉降和火山垂直排放剖面发挥相对较小的作用。
The long duration of the 2010 Eyjafjallajökull eruption provided a unique opportunity to measure a widely dispersed volcanic ash cloud. Layers of volcanic ash were observed by the European Aerosol Research Lidar Network with a mean depth of 1.2 km and standard deviation of 0.9 km. In this paper we evaluate the ability of the Met Office's Numerical Atmospheric‐dispersion Modelling Environment (NAME) to simulate the observed ash layers and examine the processes controlling their depth. NAME simulates distal ash layer depths exceptionally well with a mean depth of 1.2 km and standard deviation of 0.7 km. The dominant process determining the depth of ash layers over Europe is the balance between the vertical wind shear (which acts to reduce the depth of the ash layers) and vertical turbulent mixing (which acts to deepen the layers). Interestingly, differential sedimentation of ash particles and the volcano vertical emission profile play relatively minor roles.