Earth:Mean high water springs
Mean high water springs (MHWS) is the averaged highest level that spring tides reach over many years (often the last 19). Within this, to ensure anomalous levels are tempered, at least two successive high waters during the highest-tide 24 hours are taken. Spring tides are those when the moon is in a direct alignment with the sun (thus new or full) and in many extra-tropics places when its declination is 23.5°, its maximum.[1] In equatorial, tropical seas, such as the Banda Sea such tides (bulges) occur when there is such an alignment and the declination of the moon is more towards its 0° average, thus more overhead or antiposed.
Such a local level is generally close to the "high water mark" where debris accumulates on a tidal shore on about two days six months apart (and nearby days) annually.
The levels are local as some places are nearer to or form places of almost no tides in and around each ocean (amphidromic points).
See also
- Mean low water spring
- Neap Tides
References
External links
- Definitions of various tide related terms on the Proudman Oceanographic Laboratory site.
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