At present, however, even the highest possible quality salinity measurements (uncertainty of about 0.001 g/kg) are not adequate for climate studies in the deep ocean, except for regions close to the sources of deep water 5, 6.įor example, in the western North Pacific along 149☎, the meridional gradients of temperature and salinity in the deep ocean are about 2 mK and 0.0002 g/kg per 100 km, respectively 7. Ocean salinity is also being recognized as an important indicator of climate change Antarctic ice-sheet melting is freshening the bottom water around Antarctica 4. A supercomputer simulation has shown that surface warming events in the Southern Ocean may cause significant temperature changes in the North Pacific deep water 3. Recent high-quality hydrographic observations have revealed bottom water warming: 2 mK decade −1 in the North Pacific 1 and around 30 mK decade −1 in the Southern Ocean 2. Surface water that cools around Antarctica sinks and forms bottom water, which spreads over the entire global ocean. The ocean’s central role in the climate system results from its great capacity to store and transport heat and water and exchange these with the atmosphere. Oceanic and atmospheric circulations transfer this energy from the low latitudes of Earth’s surface to higher latitudes. The Earth’s climate system is driven by energy from the sun. The ultra high-resolution density sensor will contribute notably to climate research at full ocean depth and measurement of seawater sampled from the deep ocean, to research on metrology to establish the traceability of salinity measurements, and to submarine resource exploration to detect spatial changes in the absolute salinity anomaly by combining with conventional conductance-based salinity measurements. These resolution values are the best in the history of seawater density measurements. The resolution of the density sensor is 0.00006 kg/m 3 for changing temperature at constant salinity and pressure, 0.00012 kg/m 3 for changing salinity at constant temperature and pressure, and 0.00010 kg/m 3 for changing pressure at constant temperature and salinity. We developed a state-of-the-art density sensor for seawater measurements based on measuring the refractive index by the interference method. ĭensity of crude oil, Density of fuel oils, Density of lubricating oil and Density of jet fuel as function of temperature.Īs shown in the figures, the change in density is not linear with temperature - this means that the volumetric expansion coefficient for water is not constant over the temperature range.The interference method is one of the most sensitive methods for measuring the refractive index of seawater. įor other substances, see density and specific weight of acetone, air, ammonia, argon, benzene, butane, carbon dioxide, carbon monoxide, ethane, ethanol, ethylene, helium, hydrogen, methane, methanol, nitrogen, oxygen, pentane, propane and toluene. See also other properties of Water at varying temperature and pressure : Boiling points at high pressure, Boiling points at vacuum pressure, Dynamic and kinematic viscosity, Enthalpy and entropy, Heat of vaporization, Ionization Constant, pK w, of normal and heavy water, Melting points at high pressure, Prandtl number, Properties at Gas-Liquid Equilibrium Conditions, Saturation pressure, Specific gravity, Specific heat (heat capacity), Specific volume, Thermal conductivity, Thermal diffusivity and Vapour pressure at gas-liquid equilibrium. See Water and Heavy Water for thermodynamic properties at standard condtions. The density of water depends on temperature and pressure as shown below: Note! Temperature must be within the ranges 0-370 ☌, 32-700 ☏, 273-645 K and 492-1160 °R to get valid values. The output density is given as g/cm 3, kg/m 3, lb/ft 3, lb/gal(US liq) and sl/ft 3. The calculator below can be used to calculate the liquid water density at given temperatures. See more about the difference between mass and weight Online Water density Calculator The density of water is 1.940 sl/ft 3at 39 ☏ (4 ☌), and the specific weight in Imperial units is In the Imperial system the mass unit is the slug, and is derived from the pound-force by defining it as the mass that will accelerate at 1 foot per square second when a 1 pound-force acts upon it :ġ = 1 * 1 and 1 = 1 /1 In the SI system, specific weight of water at 4☌ will be: G = acceleration due to gravity, units typically and value on Earth usually given as 9.80665 m/s 2or 32.17405 ft/s 2 Specific weight is the ratio of the weight to the volume of a substance: Pure water has its highest density 1000 kg/m 3 or 1.940 slug/ft 3 at temperature 4☌ (=39.2☏). Density is the ratio of the mass to the volume of a substance:
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