![ocean water density ocean water density](https://svs.gsfc.nasa.gov/vis/a000000/a003600/a003652/SSTMap_8000x4000.jpg)
These in situ measurements are often made with a CTD instrument, where the instrument is placed in the ocean water from a ship or a platform. Density is usually calculated from in situ measurements of salinity, temperature and pressure. If you wanted to measure the density of ocean water, you would have to collect a sample of sea water and bring it back to the laboratory to be measured. The density of ocean water is rarely measured directly. Vertical circulation is thus limited because it is easier for water to move along lines of constant density (isopycnals) than across them. Water tends to move horizontally throughout the deep ocean, moving along lines of equal density. The deep ocean is layered with the densest water on bottom and the lightest water on top. Circulation in the depths of the ocean is referred to as thermohaline circulation. Whereas the circulation of surface waters of the ocean are driven by winds, the circulation of the deep waters are driven by density differences. So a parcel of water with higher salinity can actual float on top of water with lower salinity if the parcel with higher salinity is quite a bit warmer than the lower salinity parcel. Temperature has a greater effect on the density of water than salinity does. Increasing salinity also increases the density of sea water. Ocean water, with an average salinity of 35 psu, freezes at 28.5 oF (-1.94 oC). The density of ocean water continuously increases with decreasing temperature until the water freezes. The two main factors that affect density of ocean water are the temperature of the water and the salinity of the water. The density of ocean water at the sea surface is about 1027 kg/m 3. If there is no horizontal density variation, then the sea density origin is at $(0, 0, \text)$, where $X$ and $Y$ are the origin coordinates for the horizontal variation axis.A fun activity dealing with the density of salt water versus fresh water We define the sea density origin as follows: Sea density originĪs explained above, for all hydrodynamic calculations other than buoyancy OrcaFlex uses a single sea density value, that at the sea density origin. The default value of ~ indicates that no horizontal variation or scaling is performed. This allows you to, for example, scale a vertical density profile given non-dimensionally. You may also give a constant numeric value here, which will be applied to the density throughout as a uniform scaling factor.
![ocean water density ocean water density](https://image3.slideserve.com/6604397/variations-in-ocean-water-density-with-depth-l.jpg)
Where variation of density with depth has been defined, the factor will be applied at all depths. The variation is presented as a dimensionless multiplicative factor. The horizontal variation factor is assumed to be constant in the direction normal to the axis.
![ocean water density ocean water density](https://eos.org/wp-content/uploads/2015/07/004741_HANSELL-F02_Web1.jpg)
Modelling density variation with horizontal position requires you to define a horizontal variation factor variable data source, which specifies the variation along a given axis. It is possible to model a dry land system in OrcaFlex by using constant density with value zero. Linear interpolation is used to obtain the density at intermediate levels, and the data are truncated at both ends of the table.