Directional recording of swell from distant storms
Directional recording of swell from distant storms
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DOI：
10.1098/rsta.2013.0039
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
W. Munk;G. Miller;F. Snodgrass;N. Barber
中科院分区：
文献类型：
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作者：
W. Munk;G. Miller;F. Snodgrass;N. Barber
大约15年前，在本刊的几页上，我们中的一个人展示了康沃尔北部彭丁和佩兰珀斯附近海浪和膨胀的功率谱（Barber & Ursell 1948）。这些光谱的显著特征是峰向更高的频率连续移动。这是来自相当明确的源的色散波列的预期行为。风暴产生广泛的频谱；低频与最大的群速度有关，因此首先到达较远的站点。峰值频率的时间增长速率决定了起源的距离和时间。通过这种方法，Barber & Ursell能够识别出北大西洋低气压区、佛罗里达附近的热带风暴和合恩角附近的风暴，它们分别距离康沃尔站1200英里、2800英里和6000英里。测量结果与简单的经典结果一致，即每个频率/以适当的群速度传播，V = g/(47[/*])。目前的研究在某种意义上是对Barber & Ursell工作的改进。频率分辨率和灵敏度都提高了一个数量级，这使得探测和分辨以前无法探测到的气象源成为可能。来自印度洋的对跖涌浪就是一个很好的例子
Almost fifteen years ago in the pages of this Journal, one of us presented power spectra of ocean waves and swell off Pendeen and Perranporth in north Cornwall (Barber & Ursell 1948). The outstanding feature of these spectra is the successive shift of peaks toward higher frequencies. This is the expected behaviour of dispersive wave trains from rather well-defined sources. Storms generate a broad spectrum of frequencies; the low frequencies are associated with the largest group velocity and accordingly are the first to arrive at distant stations. The time rate of increase in the frequency of peaks determines the distance and time of origin. In this way Barber & Ursell were able to identify the dispersive arrivals with a low pressure area in the North Atlantic, a tropical storm off Florida, and a storm off Cape Horn, at distances of 1200, 2800, and 6000 miles, respectively, from the Cornish stations. The measurements were consistent with the simple classical result that each frequency,/, is propagated with its appropriate group velocity, V = g/(47[/*). The present study is in a sense a refinement to the work of Barber & Ursell. The frequency resolution and sensitivity have each been increased by an order of m agnitude, and this makes it possible to detect and resolve meteorological sources that have previously been out of reach. The antipodal swell from the Indian Ocean is a case in point