Anisotropic diffusion coefficients and the global spread of volcanic dust
Anisotropic diffusion coefficients and the global spread of volcanic dust
复制标题
各向异性扩散系数和火山尘的全球扩散
DOI：
10.1029/jc075i015p03007
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发表时间：
1970
影响因子：
--
通讯作者：
A. Dyer
中科院分区：
文献类型：
--
作者：
A. Dyer
火山灰在全球范围内的扩散。1963年3月17日的阿贡火山喷发是根据太阳直接辐射的减少来评估的。这些数据表明，建立一个赤道水库的高度约22公里，然后在冬季向极地运输到每个半球。向极移动的尘埃波在任何一个季节似乎都有恒定的振幅，在30°和90°纬度之间，向极移动的速度为40 cm/s。在下列情况下，找到了扩散系数Kyy和Kyz的解析解：（1）ε ν ε = 0，即，没有恶意的举动(2)v (3)与（2）相同，但也假设纬度衰减，试图考虑火山气体产物产生的平流层尘埃颗粒源。Kyy的结果与其他工作者的结果基本一致，但Kyz的值似乎过高，特别是在30°-60°纬度地区。据推测，更好的协议，可以找到，如果扩散系数被选择为随季节变化。
The global spread of volcanic dust from the Mt. Agung eruption of March 17, 1963, is assessed on the basis of the decrement in direct solar radiation. The data suggest the establishment of an equatorial reservoir at height of about 22 km, followed by poleward transport into each hemisphere during winter. The poleward-moving waves of dust appeared to have constant amplitude in any one season, with a poleward progression rate of 40 cm sec−1 between 30° and 90° latitude. Analytic solutions are found for the diffusion coefficients Kyy and Kyz for the following cases: (1) 〈ν〉 = 0, i.e., no mean motion. (2) 〈ν〉 = 20 sin 6ϕ, corresponding to a three-cell pattern for the meridional circulation. (3) Same as (2) but with assumption of also latitude attenuation, in an attempt to allow for a stratospheric source of dust particles from gaseous products of the volcano. The results for Kyy are in general agreement with findings of other workers, but the values of Kyz appear to be too high, particularly in the region 30°–60° latitude. It is speculated that better agreement could be found if the diffusion coefficients were chosen to vary seasonally.