Intra‐annual variations in atmospheric dust and tritium in the North Pacific region detected from an ice core from Mount Wrangell, Alaska
Intra‐annual variations in atmospheric dust and tritium in the North Pacific region detected from an ice core from Mount Wrangell, Alaska
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DOI：
10.1029/2006jd008121
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发表时间：
2007-05
影响因子：
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通讯作者：
T. Yasunari;T. Shiraiwa;Syosaku Kanamori;Y. Fujii;M. Igarashi;K. Yamazaki;C. Benson;T. Hondoh
中科院分区：
文献类型：
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作者：
T. Yasunari;T. Shiraiwa;Syosaku Kanamori;Y. Fujii;M. Igarashi;K. Yamazaki;C. Benson;T. Hondoh
[1]北太平洋受到各种季节性气候现象和物质循环的影响。因此，年内冰芯数据对于评估气候变化是必要的。为了评估过去的变化，在阿拉斯加的兰格尔火山顶端钻了一个50米长的冰芯。对粉尘数量、氚浓度和稳定氢同位素进行了分析。所涉时期为1992至2002年。我们发现，每年春季，指示长距离输送的细尘(0.52-1.00μm)和粗尘(1.00-8.00μm)的浓度都呈上升趋势。此外，它们的浓度在2000年后急剧增加，与最近亚洲春季沙尘暴发的增加相对应。此外，2001年春季出现了东亚自1979年以来最大的沙尘暴。因此，我们的发现表明，每年春天，亚洲沙尘都会对兰格尔山造成严重污染。平流层示踪剂氚几乎每年都有晚春最大值，我们发现这对确定北太平洋地区晚春的冰芯年代很有用。我们还发现，从春末到夏季，计算的氚和细粉尘通量之间存在着很高的正相关。我们认为，平流层-对流层交换与亚洲沙尘暴的年际关系在春末最为密切，因为它们在夏季的活动较弱。兰盖尔山冰核对于评估遥远过去北太平洋周围的尘埃和氚环流是重要和有用的，可能有年度内的时间尺度信息。
[1] The North Pacific is subject to various seasonal climate phenomena and material circulations. Therefore intra-annual ice core data are necessary for an assessment of the climate variations. To assess past variations, a 50-m ice core was drilled at the summit of Mount Wrangell Volcano, Alaska. The dust number, tritium concentrations, and stable hydrogen isotope were analyzed. The period covered was from 1992 to 2002. We found that the concentrations of both fine dust (0.52–1.00 μm), an indicator of long-range transport, and coarse dust (1.00–8.00 μm) increased together every spring. Moreover, their concentrations increased drastically after 2000, corresponding to the recent increase in Asian dust outbreaks in spring. Additionally, an increase in the spring of 2001 corresponded to the largest dust storm recorded in east Asia since 1979. Therefore our findings imply that Asian dust strongly polluted Mount Wrangell every spring. The stratospheric tracer, tritium, had late spring maxima almost every year, and we found this useful for ice core dating to identify late spring in the North Pacific region. We also found that a high positive annual correlation existed between the calculated tritium and fine dust fluxes from late spring to summer. We propose that an annual relationship between the stratosphere-troposphere exchange and Asian dust storm are most closely connected in late spring because their activities are weak in summer. The Mount Wrangell ice core is important and useful for assessing the dust and tritium circulation in the distant past around the North Pacific with probable intra-annual timescale information.