Seasonal and spatial variations in the ocean-coupled ambient wavefield of the Ross Ice Shelf
Seasonal and spatial variations in the ocean-coupled ambient wavefield of the Ross Ice Shelf
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DOI：
10.1017/jog.2019.64
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发表时间：
2019-09
影响因子：
3.4
通讯作者：
M. Baker;R. Aster;R. Anthony;J. Chaput;D. Wiens;A. Nyblade;P. Bromirski;P. Gerstoft;R. Stephen
中科院分区：
文献类型：
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作者：
M. Baker;R. Aster;R. Anthony;J. Chaput;D. Wiens;A. Nyblade;P. Bromirski;P. Gerstoft;R. Stephen
罗斯冰架（RIS）是响应大气、海洋和固体地球源过程激发的宽带多模地震波场的宿主。从2014年底到2017年初，RIS上安装了一个34个站点的宽带地震仪网络，对地球上最大的浮冰架和地面冰架进行了连续的振动观测。我们描述了宽带环境波场功率的时空变化，重点研究了与初级（10-20 s）和次级（5-10 s）微震信号相关的周期带，以及冰锋附近的海源过程（0.4-4.0 s）。由于与固体地球横波几乎完全隔绝，浮动台站的水平分量信号全年压倒性地反映海洋激励。所有时期的光谱都显示出受到冰架前沿附近海冰浓度的强烈调制。连续和广泛的海冰充分地抑制了海浪耦合，因此冬季的背景水平可以接近或超过南极洲陆基站的水平。
Abstract The Ross Ice Shelf (RIS) is host to a broadband, multimode seismic wavefield that is excited in response to atmospheric, oceanic and solid Earth source processes. A 34-station broadband seismographic network installed on the RIS from late 2014 through early 2017 produced continuous vibrational observations of Earth's largest ice shelf at both floating and grounded locations. We characterize temporal and spatial variations in broadband ambient wavefield power, with a focus on period bands associated with primary (10–20 s) and secondary (5–10 s) microseism signals, and an oceanic source process near the ice front (0.4–4.0 s). Horizontal component signals on floating stations overwhelmingly reflect oceanic excitations year-round due to near-complete isolation from solid Earth shear waves. The spectrum at all periods is shown to be strongly modulated by the concentration of sea ice near the ice shelf front. Contiguous and extensive sea ice damps ocean wave coupling sufficiently so that wintertime background levels can approach or surpass those of land-sited stations in Antarctica.