{"id":356,"date":"2020-10-22T13:21:28","date_gmt":"2020-10-22T13:21:28","guid":{"rendered":"https:\/\/maritimesa.org\/nautical-science-grade-11\/?p=356"},"modified":"2020-10-22T13:21:28","modified_gmt":"2020-10-22T13:21:28","slug":"definitions","status":"publish","type":"post","link":"https:\/\/maritimesa.org\/nautical-science-grade-11\/2020\/10\/22\/definitions\/","title":{"rendered":"Definitions"},"content":{"rendered":"<p><strong>Highest Astronomical Tide (HAT) and Lowest Astronomical Tide (LAT).<\/strong><br \/>\nThese levels are predicted to occur under average meteorological conditions and under any combination of astronomical conditions. They will not be reached every year. They are also not the extreme levels that can be reached, as storm surges and other meteorological conditions can cause considerably higher and lower levels to occur.<\/p>\n<p><strong>Mean High Water Springs (MHWS) and Mean Low Water Springs (MLWS).<\/strong><br \/>\nThe height of mean high water springs is the average over a year of the heights of two successive high waters during those periods of 24 hours (once every fortnight) when the range of the tide is greatest. Mean low water springs is the average height obtained from two successive low waters during the same period.<\/p>\n<p><strong>Mean High Water Neaps (MHWN) and Mean Low Water Neaps (MLWN). <\/strong><br \/>\nThe height of mean high water neaps is the average over a year of the heights of two successive high waters during those periods of 24 hours (once every fortnight) when the range of the tide is least. Mean low water neaps is the average height obtained from two successive low waters during the same period.<\/p>\n<p><strong>Mean Sea Level (MSL).<\/strong><br \/>\nThis is the mean of the heights of MHWS, MLWS, MHWN and MLWN.<\/p>\n<p><strong>Tidal cycle.<\/strong><br \/>\nThe values of MHWS, MLWS, MHWN and MLWN vary from year to year in a cycle of approximately 18.6 years.<\/p>\n<p>For a graphical presentation of the relationship between the above definitions, the following diagram shows<br \/>\nthe physical relationship between the various defined levels of tide and the chart datum:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-97\" src=\"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1.jpg\" alt=\"\" width=\"900\" height=\"642\" srcset=\"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1.jpg 900w, https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1-300x214.jpg 300w, https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1-768x548.jpg 768w, https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1-205x146.jpg 205w, https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1-50x36.jpg 50w, https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-content\/uploads\/sites\/6\/2020\/10\/11.1.7.3_fig_1-105x75.jpg 105w\" sizes=\"(max-width: 900px) 100vw, 900px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Highest Astronomical Tide (HAT) and Lowest Astronomical Tide (LAT). These levels are predicted to occur under average meteorological conditions and under any combination of astronomical conditions. They will not be reached every year. They are also not the extreme levels that can be reached, as storm surges and other meteorological [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,59,62],"tags":[],"class_list":["post-356","post","type-post","status-publish","format-standard","hentry","category-11-1-navigation","category-11-1-7-the-tides","category-11-1-7-3-definitions"],"_links":{"self":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/posts\/356"}],"collection":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/comments?post=356"}],"version-history":[{"count":1,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/posts\/356\/revisions"}],"predecessor-version":[{"id":357,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/posts\/356\/revisions\/357"}],"wp:attachment":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/media?parent=356"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/categories?post=356"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-11\/wp-json\/wp\/v2\/tags?post=356"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}