Still-water level or still-water sea level (SWL) is the level of the sea with motions such as wind waves averaged out.[5]Then MSL implies the SWL further averaged over a period of time such that changes due to, e.g., the tides, also have zero mean. Global MSL refers to a spatial average over the entire ocean.
One often measures the values of MSL in respect to the land; hence a change in relative MSL can result from a real change in sea level, or from a change in the height of the land on which the tide gauge operates.In the UK, the ordnance datum (the 0 metres height on UK maps) is the mean sea level measured at Newlyn in Cornwall between 1915 and 1921.[6] Before 1921, the vertical datum was MSL at the Victoria Dock, Liverpool.Since the times of the Russian Empire, in Russia and its other former parts, now independent states, the sea level is measured from the zero level of Kronstadt Sea-Gauge. In Hong Kong, "mPD" is a surveying term meaning "metres above Principal Datum" and refers to height of 0.146 m above chart datum and 1.304 m below the average sea level.[7]In France, the Marégraphe in Marseilles measures continuously the sea level since 1883 and offers the longest collated data about the sea level. It is used for a part of continental Europe and the main part of Africa as the official sea level. Spain uses the reference to measure heights below or above sea level at Alicante, and another European vertical elevation reference (European Vertical Reference System) is to the Amsterdam Peil elevation, which dates back to the 1690s.
Maxsea Time Zero Liste Code Key Mapl
On other planets that lack a liquid ocean, planetologists can calculate a "mean altitude" by averaging the heights of all points on the surface. This altitude, sometimes referred to as a "sea level" or zero-level elevation, serves equivalently as a reference for the height of planetary features.
SUMMARY: These heritage twice-weekly global 50km maps summarized the current DHW and HotSpot values at the time. At a glance, this product outlined the location, coverage, and potential risk level of the current bleaching heat stress. Alert levels use the same definition as our Satellite Bleaching Alert email system, but in the Bleaching Alert Area product every pixel had an alert level defined and color-coded. Global data were at 0.5-degree (50km) resolution and were updated twice-weekly.
CRW's heritage twice-weekly global 50km Coral Bleaching Virtual Stations provided near real-time satellite monitoring information on heat stress conducive to coral bleaching for 227 reef sites (officially), as well as 26 additional reef sites around the world (Liu et al., 2001). The information was extracted from near real-time satellite global SST measurements and derived indices of coral bleaching-related heat stress (see the sections above on SST, SST Anomaly, Coral Bleaching HotSpot, and DHW for more details) from 0.5-degree (50km) water pixels surrounding or close to the reef sites. Information listed for each reef site included the reef site name, current (at that time) heat stress status, current DHW value in C-weeks, historical maximum DHW, current SST value in degrees Celsius, and the MMM SST climatologies value. A map showing a particular reef site (Virtual Station) and its satellite pixel is accessible by clicking on the reef name. The map page also provided links to other coral bleaching heat stress monitoring products, inclduing the free, automated Satellite Bleaching Alert e-mail system.
Please note that since the DHW was a 12-week accumulation of Coral Bleaching HotSpots, it was possible for a location to have had a non-zero DHW value when the HotSpot value was less than 1 C or even 0 C. Hence, at a status level of "No Stress" or "Bleaching Watch," it was possible for the corresponding DHW value to have been greater than 0 C-week. This condition simply meant that there has been heat stress at that location sometime within the prior 3 months, but the local conditions were not currently (at that time) stressful for corals. Previous heat stress exposure still may have had adverse impacts on the corals, although recovery also may have been underway.
In each time series graph, the corresponding heat stress condition (see the table in the Coral Bleaching Virtual Stations section) related to coral bleaching was color-coded and plotted in a bar at the bottom of the time series graphs. The thermal condition was categorized in the five bleaching alert levels. The area below the DHW time series was also filled with colors corresponding to the color-coded bleaching alert levels whenever bleaching related heat stress was present. At Bleaching Alert Level 1, significant bleaching was expected at the site within a few weeks of the alert. An accumulation of DHW of 8 C-weeks triggered a Bleaching Alert Level 2, at which point severe, widespread bleaching and significant coral mortality were likely.
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
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