Observations and Modeling of Coastal Boulder Transport and Loading During Super Typhoon Haiyan
Observations and Modeling of Coastal Boulder Transport and Loading During Super Typhoon Haiyan
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DOI：
10.1142/s0578563416400040
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发表时间：
2016-03-01
影响因子：
2.4
通讯作者：
Toride, Kinya
中科院分区：
文献类型：
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作者：
Kennedy, Andrew B.;Mori, Nobuhito;Toride, Kinya
菲律宾卡利科安岛的超级台风海燕将数量高达数百/数千吨、质量高达约 30 吨的巨石运送到岸上，最高地面高度可能超过 9m，终端位置高达约 180m 内陆。沿海巨石运动的一维布辛涅斯克后报显示，在亚重力斜孔的前部发起了间歇性运输。人们发现传输距离对波高高度敏感，足以使终端位置的观测可能成为估计粗略古风暴震级的可行方法。钻孔前部的大加速度产生了显着的惯性力，特别是对于较大的巨石，但在所有模拟中阻力的均方根大小都更大。使用模型巨石测试了广泛使用的从巨石属性推断流体速度的关系 - 将模拟终端巨石位置处的推断速度与这些位置处的最大计算布辛涅斯克流体速度进行比较，发现明显较低。对于移动性强的较小巨石来说，推断速度的这种低估最为严重。当假设弗劳德单位数来估计水流深度时，对于大巨石来说，推断的阻力载荷与模型值相比更加准确。尽管这些巨石明确是由风暴波搬运的，但它们的巨大尺寸和移动距离冒险进入了被认为是海啸的范围。因此，必须谨慎解释中低纬度地区来源不明的沿海巨石场的来源。
Boulders numbering in the high hundreds/low thousands, and with masses up to similar to 30 tonnes, were transported onshore by Super Typhoon Haiyan in Calicoan Island, Philippines to maximum ground elevations that could exceed 9m and terminal positions up to similar to 180m inland. One-dimensional Boussinesq hindcasts of coastal boulder motion showed intermittent transport initiated at the fronts of infragravity swash bores. Transport distances were found to be highly sensitive to wave-height, enough so that observations of terminal positions may be a viable method of estimating rough paleostorm magnitudes. The large accelerations at bore fronts generated significant inertial forces, particularly for larger boulders, but drag forces had greater root-mean-square magnitudes in all simulations. Widely used relations to infer fluid velocities from boulder properties were tested using modeled boulders - inferred velocities at modeled terminal boulder positions were compared to maximum computed Boussinesq fluid velocities at these locations and found to be significantly lower. This underprediction of inferred velocities was greatest for smaller boulders that were strongly mobile. Inferred drag loads compared to modeled values were somewhat more accurate for large boulders when a Froude number of unity was assumed to estimate flow depths. Although these boulders were unequivocally transported by storm waves, their large sizes and distances traveled venture into what has been considered the tsunami range. Thus, care must be taken to interpret the provenance of coastal boulder fields with unknown origin for lower to mid-latitude regions.