Tidal Components of Currents in Submarine Canyons
Tidal Components of Currents in Submarine Canyons
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DOI：
10.1086/628199
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发表时间：
1976-05
期刊：
影响因子：
--
通讯作者：
F. P. Shepard
中科院分区：
文献类型：
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作者：
F. P. Shepard
海底峡谷头部上下交替的水流具有高频反转现象，一般情况下，交替的时间间隔随着峡谷轴深度的增加而增加，直至接近半日潮周期。发现这种半日关系的深度显然与潮差有关。根据现有资料，在1.5-2.5m的潮差范围内，显示当前反转期与半日潮之间关系所需的深度通常在250-350m之间；在3个潮差较大的峡谷中，1400m以上记录的周期比半日潮周期短，比250-1400m之间记录的周期更不规则。在少数可获得的长周期记录中，当前逆转周期的长度在大潮期间大于小潮期间。在一些记录中观察到了长达25小时的昼夜潮汐周期，在大的大潮期间，这两个日潮汐的高度相差很大。
Alternating up- and downcanyon currents in the heads of submarine canyons have high-frequency reversals, and, in general, the time interval between alternations increases with depth of the canyon axis until it approximates the period of semidiurnal tides. The depth at which this semidiurnal relationship is found is apparently related to the tidal range. According to available information, with a tidal range of 1.5 and 2.5 m, the depth necessary to show the relationship between the current reversal period and the semidiurnal tide is usually between 250 and 350 m; whereas, if the range is of the order of 1 or less, the depth necessary to develop the tidal relationship is as great as 1,500 m. In three canyons with relatively large tidal range, records taken from depths of more than 1,400 m have alternation cycles shorter than the period of the semidiurnal tide and more irregular than the records from depths between 250 and 1,400 m. In the few available long-period records, the length of the current reversal cycle was found to be greater during spring tides than during neap tides. Cycles as long as the 25-hour diurnal tides were observed in portions of a few records where during large spring tides the heights of the two daily tides contrasted greatly.