< p >的时代潮流(a.k.。,< a href = " http://co-ops.nos.noaa.gov/publications/glossary2.pdf " rel = " nofollow noreferrer " >的年龄阶段不平等< / >,< a href = " https://en.wikipedia.org/wiki/Lunitidal_interval " rel = " nofollow noreferrer " >间隙< / >)在一个位置是一个术语,表示一个完整的的间隔时间或新月(平衡半日潮力最大时),和当地大潮的时候。在大多数情况下,有一个最大的力量和发生的最大仰角之间的延迟。< / p > < p >的潮汐力产生一波又一波的波长很长的旅游在海洋的速度由浅水前进波速度方程,c = \ sqrt (gH)美元,H是美元水深的地方。月亮阶段和他们之间的延迟影响潮流是波所需的时间环游大海。< / p > < p >有两种不同的机制来考虑:共振和摩擦。< / p > < p >的时代潮流是类似于强制的相位滞后的增加,线性阻尼谐振子随着频率的增加是自十九世纪以来闻名。阻尼振荡类比并不能解释相位大小在真实的海洋。< / p > < p >的摩擦是必要的来解释观察到的时间滞后。< a href = " http://dx.doi.org/10.1111/j.1365 - 246 x.1941.tb00439.x”rel = " nofollow noreferrer " > Proudman(1941) < / >显示,通过对沿海地区,包括摩擦影响的积极的时代潮流出现在潮汐的解决方案。如果有共振频率在海洋盆地接近半日频率(M_2,美元S_2美元…),摩擦增强潮导致更高的年龄延迟值。 Garrett & Munk (1971) and Webb (1973) provided a methodology for the calculation and estimates around the oceans. The longest delays (longer than 60 hours) were estimated in areas with the largest continental shelf, as they represent areas of strong tidal dissipation: the North Sea, the Ross Sea, Hudson Strait, the shelf off Argentina, the Bering Sea, and the Sea of Okhotsk. The age of tide can be obtained from the harmonic constants by dividing the difference in phases of the $S_2$ and $M_2$ constituents by frequency separation between both constituents: $ Age\_of\_tide = {Phase\_of\_M_2 - Phase\_of\_S_2 \over 1.0163 }$, where the phases are measured in degrees and the age of tide is in hours.