Glacially sourced dust as a potentially significant source of ice nucleating particles
Glacially sourced dust as a potentially significant source of ice nucleating particles
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DOI：
10.1038/s41561-019-0314-x
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发表时间：
2019-04
影响因子：
18.3
通讯作者：
Y. Tobo;K. Adachi;P. DeMott;T. Hill;D. Hamilton;N. Mahowald;Naoko Nagatsuka;S. Ohata;J. Uetake;Y. Kondo;M. Koike
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文献类型：
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作者：
Y. Tobo;K. Adachi;P. DeMott;T. Hill;D. Hamilton;N. Mahowald;Naoko Nagatsuka;S. Ohata;J. Uetake;Y. Kondo;M. Koike
风成尘在混合相云中作为冰核粒子，从而改变云的性质和寿命。冰川外溢平原被认为是寒冷高纬度地区的主要粉尘来源。由于最近冰川迅速而广泛的退缩，预计高纬度地区的粉尘排放将增加，特别是在对气候变化高度敏感的北极地区。然而，高纬度尘埃对北极低空云层冰核的潜在贡献尚未得到充分承认。在这里，我们表明，与典型的矿物粉尘相比，斯瓦尔巴群岛的冰川外溢沉积物（冰川来源粉尘的代表）在与混合相云形成相关的条件下具有非常高的冰成核能力。沉积物的高冰成核能力可能是由于存在少量的有机物（<1 wt%的有机碳）而不是矿物成分。此外，我们的密集野外测量和模式模拟结果表明，在斯瓦尔巴群岛及其周围地区的尘埃排放的影响下，预计夏季斯瓦尔巴群岛地区大气冰核粒子的浓度将增加。我们认为，高纬度沙尘源有可能显著影响北极低层云的冰川作用。
Aeolian dusts serve as ice nucleating particles in mixed-phase clouds, and thereby alter the cloud properties and lifetime. Glacial outwash plains are thought to be a major dust source in cold, high latitudes. Due to the recent rapid and widespread retreat of glaciers, high-latitude dust emissions are projected to increase, especially in the Arctic region, which is highly sensitive to climate change. However, the potential contribution of high-latitude dusts to ice nucleation in Arctic low-level clouds is not well acknowledged. Here we show that glacial outwash sediments in Svalbard (a proxy for glacially sourced dusts) have a remarkably high ice nucleating ability under conditions relevant for mixed-phase cloud formation, as compared with typical mineral dusts. The high ice nucleating ability of the sediments is probably governed by the presence of small amounts of organic matter (<1 wt% organic carbon) rather than mineral components. In addition, our results from intensive field measurements and model simulations indicate that the concentrations of atmospheric ice nucleating particles over the Svalbard region are expected to be enhanced in the summertime under the influence of dust emissions from Svalbard and its surroundings. We suggest that high-latitude dust sources have the potential to significantly influence glaciation of Arctic low-level clouds.