Integrating retrievals of volcanic cloud characteristics from satellite remote sensors: a summary
Integrating retrievals of volcanic cloud characteristics from satellite remote sensors: a summary
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DOI：
10.1098/rsta.2000.0605
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发表时间：
2000-05
期刊：
影响因子：
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通讯作者：
W. Rose;G. Bluth;Jerome Ernst
中科院分区：
文献类型：
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作者：
W. Rose;G. Bluth;Jerome Ernst
火山爆发是迅速而突然地将气体和细颗粒分散到大气中的事件，这一过程最方便地从天气卫星角度进行研究，遥感为空间和时间测量提供了实用工具。气象卫星提供了大约20年的存档数据，可以对这些数据进行分析，以测量空间二维阵列中二氧化硫和细火山灰的质量，并与其他气象数据相结合。卫星数据提供了一种定量研究火山-大气相互作用的工具。它们为了解具有重大健康危害的细硅酸盐的命运和运输以及解决火山云对喷气式飞机的危害问题提供了具有独特价值的信息。对卫星数据的研究表明：(1)辐合的板块边界火山形成的火山云中含有大量多变的SO2过量。(2)火山云在大气停留的第2天SO2明显高于第1天，表明早期火山H2S可能正在转化为SO2。(3)在平流层中，二氧化硫完全转化为硫酸盐的速率约为120天。平流层火山云中SO2的e折叠速率约为35天，而仅到达平流层的火山云中SO2的e折叠速率较快（e折叠速率仅为几天）。后者限制了较小的火山喷发造成的平流层气溶胶积聚。(4)在10 h或更长时间后恢复的漂流火山云中，细火山灰（直径小于0.25 μm）似乎只占岩浆总喷发质量的一小部分（小于总质量的2%），也占细火山灰总喷发质量的一小部分（小于20%）。这也许可以用这样一个事实来解释：火山云内部的聚集过程大大减少了总质量。(5)在大喷发的火山云中，细灰的数量减少得更快，支持Pinto等人1989年提出的自清除过程。(6)有相当多的证据表明，冰在火山灰的沉降和聚集中起着重要作用。(7)在许多情况下，火山云分离成高二氧化硫含量部分和低火山灰含量部分。这两部分遵循不同的轨迹，较低的富含火山灰的部分受到与潮湿对流层空气相互作用的影响。
Volcanic eruptions are events that rapidly and suddenly disperse gases and fine particles into the atmosphere, a process most conveniently studied from the synoptic satellite perspective, where remote sensing offers a practical tool for spatial and temporal measurements. Meteorological satellites offer approximately 20 years of archived data, which can be analysed for measurements of masses of SO2 and fine volcanic ash in spatial two–dimensional arrays and integrated with other meteorological data. The satellite data offer a tool to study volcano–atmosphere interactions in a quantitative way. They provide information of unique value for understanding the fate and transport of fine silicates with significant health hazards and for addressing the problem of volcanic cloud hazards to jet aircraft. Studies of satellite data have demonstrated the following. (1) Volcanic clouds from convergent plate boundary volcanoes contain large and variable excesses of SO2. (2) The second day of atmospheric residence for volcanic clouds has significantly higher SO2 than the first, suggesting that early volcanic H2S may be converting to SO2. (3) Complete conversion of SO2 to sulphate in the stratosphere occurs at an efolding rate of approximately 120 days. SO2 loss from stratospheric volcanic clouds occurs at an e–folding rate of approximately 35 days, and the SO2 loss rate for volcanic clouds which only barely reach the stratosphere is rapid (efolding only a few days). The latter limits the stratospheric aerosol build–up from smaller eruptions. (4) Fine volcanic ash (with diameters of less than ca.25μm) in drifting volcanic clouds retrieved after 10 h or more appear to represent a small fraction (less than 2% of the total mass) of the total mass of magma erupted, and also a small fraction (less than 20%) of the total mass of fine ash erupted. This is probably explained by the fact that the total mass is greatly reduced by aggregation processes within the volcanic cloud. (5) The amounts of fine ash decrease faster in volcanic clouds of larger eruptions, supporting the self–removal processes suggested by Pinto et al. in 1989. (6) Evidence for a strong role of ice in the fallout and aggregation of volcanic cloud ash is considerable. (7) In many cases, volcanic clouds separate into higher SO2–rich portions and lower ash–rich portions. The two portions follow different trajectories and the lower, ash–rich portions are affected by interactions with moist tropospheric air.