Archive:Physical properties of the oceans - Revision history

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	'''Part of the [[Ocean engineering]] course offered by the ''[[~~Topic:~~Marine_engineering\|Wikademia Department of Marine Engineering]]'', ''[[Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''		'''Part of the [[Ocean engineering]] course offered by the ''[[Marine_engineering\|Wikademia Department of Marine Engineering]]'', ''[[Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''
	{{ntnes}}		{{ntnes}}
	==Lecture==		==Lecture==

wikademia>Wikademia: Text replace - '[[School:' to '[['

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	'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikademia Department of Marine Engineering]]'', ''[[~~School:~~Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''		'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikademia Department of Marine Engineering]]'', ''[[Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''
	{{ntnes}}		{{ntnes}}
	==Lecture==		==Lecture==

wikademia>Wikademia: moved Physical properties of the oceans to Archive:Physical properties of the oceans

2009-04-19T05:12:31Z

moved Physical properties of the oceans to Archive:Physical properties of the oceans

← Older revision	Revision as of 05:12, 19 April 2009
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	===Temperature===		===Temperature===
	[[Image:Thermohaline circulation.png\|A simplified summary of the path of the [[w:Thermohaline circulation\|Thermohaline Circulation]]. Darker arrows represent deep-water currents, while lighter arrows represent surface currents\|thumb\|600px\|right]]		[[Image:Thermohaline circulation.png\|A simplified summary of the path of the [[Wikipedia:Thermohaline circulation\|Thermohaline Circulation]]. Darker arrows represent deep-water currents, while lighter arrows represent surface currents\|thumb\|600px\|right]]

	The temperature of the oceans is not a constant, nor is it uniform throughout the oceanic mass. Sunlight imparts its energy to the ocean surfaces all summer long, and in response the ocean heats and holds that energy. Once winter comes, the oceans release that warmth back into the atmosphere in accordance with their heat capacity. This is why it is warmer near the coast in winter, and cooler in summer. Just as the ocean may act as climate control for a local area, the oceans provide convective heat transfer as they circulate, providing climatic adjustment for every latitude via the [[w:Thermohaline circulation\|Thermohaline Circulation]]. These currents are responsible for the cool weather along the US Atlantic coast, and the balmy high-latitude climate of the Mediterranean. The oceans in the Northern hemisphere are usually warmer in January, long after the summer has passed, and coolest in April, after most of their heat has been given off to the cold winter skies.		The temperature of the oceans is not a constant, nor is it uniform throughout the oceanic mass. Sunlight imparts its energy to the ocean surfaces all summer long, and in response the ocean heats and holds that energy. Once winter comes, the oceans release that warmth back into the atmosphere in accordance with their heat capacity. This is why it is warmer near the coast in winter, and cooler in summer. Just as the ocean may act as climate control for a local area, the oceans provide convective heat transfer as they circulate, providing climatic adjustment for every latitude via the [[Wikipedia:Thermohaline circulation\|Thermohaline Circulation]]. These currents are responsible for the cool weather along the US Atlantic coast, and the balmy high-latitude climate of the Mediterranean. The oceans in the Northern hemisphere are usually warmer in January, long after the summer has passed, and coolest in April, after most of their heat has been given off to the cold winter skies.

	Similarly, the temperature of the ocean is not uniform at all depths. Any swimmer may recognize the temperature differential between the water at the surface, where the sunlight is incident, and that deeper water that is much cooler. At medium depths however, there is a greatly increased temperature differential, and the water below a certain point is much cooler than the water above it. This sharp differential is called the [[w:thermocline\|thermocline]], and is present in most ocean environments, although greater in the tropics and in temperate regions during summer and nearly nonexistent in polar regions. In shallow waters, the cold air of winter can cool the surface so quickly that the water will actually "turn over", reversing the thermocline. The dependence of the thermocline upon salinity and density will be discussed further with those topics.		Similarly, the temperature of the ocean is not uniform at all depths. Any swimmer may recognize the temperature differential between the water at the surface, where the sunlight is incident, and that deeper water that is much cooler. At medium depths however, there is a greatly increased temperature differential, and the water below a certain point is much cooler than the water above it. This sharp differential is called the [[Wikipedia:thermocline\|thermocline]], and is present in most ocean environments, although greater in the tropics and in temperate regions during summer and nearly nonexistent in polar regions. In shallow waters, the cold air of winter can cool the surface so quickly that the water will actually "turn over", reversing the thermocline. The dependence of the thermocline upon salinity and density will be discussed further with those topics.

	===Density===		===Density===
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	Generally speaking, density is roughly proportional to pressure and thus depth, and inversely proportional to temperature. Density is also very dependent upon salinity as well, however, as you will learn in the next segment, this too increases with depth.		Generally speaking, density is roughly proportional to pressure and thus depth, and inversely proportional to temperature. Density is also very dependent upon salinity as well, however, as you will learn in the next segment, this too increases with depth.

	Seawater density is nearly uniform at all latitudes, although surface density lessens greatly as one nears the equator, a phenomenon due to tropical climates. This sharp difference in density within these tropical regions is called the [[w:pycnocline\|pycnocline]].		Seawater density is nearly uniform at all latitudes, although surface density lessens greatly as one nears the equator, a phenomenon due to tropical climates. This sharp difference in density within these tropical regions is called the [[Wikipedia:pycnocline\|pycnocline]].


	===Salinity===		===Salinity===

	The makeup of the oceans is paramount to all these interrelated functions. The ocean is composed of primarily water, however the chemical and biological sediments carried by rivers are present too, as are similar constituents formed from the falling of rain through pollution and the remnants of aquatic life cycles. All of this material amounts to a watery mixture often referred to as salt water, yet more accurately described as saline. [[w:Salinity\|Salinity]] is the measure of how much material is mixed in with water and is defined as the total amount of all material dissolved in seawater or "the total amount of solid materials in grams contained in one kilogram of seawater, when all the carbonate has been converted to oxide, the bromine and iodine replaced by chlorine and all organic matter completely oxidized". The average salinity of seawater is 35 parts per thousand (35 g/kg).		The makeup of the oceans is paramount to all these interrelated functions. The ocean is composed of primarily water, however the chemical and biological sediments carried by rivers are present too, as are similar constituents formed from the falling of rain through pollution and the remnants of aquatic life cycles. All of this material amounts to a watery mixture often referred to as salt water, yet more accurately described as saline. [[Wikipedia:Salinity\|Salinity]] is the measure of how much material is mixed in with water and is defined as the total amount of all material dissolved in seawater or "the total amount of solid materials in grams contained in one kilogram of seawater, when all the carbonate has been converted to oxide, the bromine and iodine replaced by chlorine and all organic matter completely oxidized". The average salinity of seawater is 35 parts per thousand (35 g/kg).

	The two most important factors in salinity determinations are density and concentration. As is indicated above, the density of a substance is contingent upon the local temperature and pressure (and salinity). At a high temperature, seawater expands and is therefore less dense, leading to a lower salinity. At low temperatures, denser water results in greater salinity. Similarly, higher concentrations of salt in the salt-water solution are increasingly saline, while higher concentrations of water are less saline.		The two most important factors in salinity determinations are density and concentration. As is indicated above, the density of a substance is contingent upon the local temperature and pressure (and salinity). At a high temperature, seawater expands and is therefore less dense, leading to a lower salinity. At low temperatures, denser water results in greater salinity. Similarly, higher concentrations of salt in the salt-water solution are increasingly saline, while higher concentrations of water are less saline.
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	On the surface where temperatures are high, density is low and salinity is low (S=33-37). Also, in areas where atmospheric temperatures are high, such as the tropics and sub-tropics, there is increased evaporation and therefore low concentrations of water in seawater and increased salinity. The temperature maximum along the equator results in low density seawater and low salinity there as well, as does the influx of fresh water from melted ice in the polar regions.		On the surface where temperatures are high, density is low and salinity is low (S=33-37). Also, in areas where atmospheric temperatures are high, such as the tropics and sub-tropics, there is increased evaporation and therefore low concentrations of water in seawater and increased salinity. The temperature maximum along the equator results in low density seawater and low salinity there as well, as does the influx of fresh water from melted ice in the polar regions.

	Salinity variations in the vertical plane are similarly organized. Generally, the highest salinity water is found at the top of the surface, where evaporation occurs. Not far below the surface mixing zone, a sharp decrease in salinity marks the transition to temperature based low density and salinity. Thereafter salinity increases with depth as the temperature drops and the density increases. This profile varies with latitude. At high latitudes (the poles) surface salinity is low and continually increases. In the tropics there is a salinity maximum at the top of the thermocline, which is the result of subtropical salinity sinking a little and flowing towards the equator. In coastal regions, the low salinity runoff creates a sharp contrast with the high salinity seawater which is called the [[w:halocline\|halocline]].		Salinity variations in the vertical plane are similarly organized. Generally, the highest salinity water is found at the top of the surface, where evaporation occurs. Not far below the surface mixing zone, a sharp decrease in salinity marks the transition to temperature based low density and salinity. Thereafter salinity increases with depth as the temperature drops and the density increases. This profile varies with latitude. At high latitudes (the poles) surface salinity is low and continually increases. In the tropics there is a salinity maximum at the top of the thermocline, which is the result of subtropical salinity sinking a little and flowing towards the equator. In coastal regions, the low salinity runoff creates a sharp contrast with the high salinity seawater which is called the [[Wikipedia:halocline\|halocline]].

	An early comparator to salinity was the chlorine concentration. This relation has been labeled as Absolute Salinity <math>(S_a)</math> and is calculated as:		An early comparator to salinity was the chlorine concentration. This relation has been labeled as Absolute Salinity <math>(S_a)</math> and is calculated as:
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	===Chemistry===		===Chemistry===
	[[Image:Deep sea vent chemistry diagram.jpg\|thumb\|right\|400px\|[[W:Hydrothermal vent\|Hydrothermal vent]] [[W:biogeochemical\|biogeochemical]] cycle diagram]]		[[Image:Deep sea vent chemistry diagram.jpg\|thumb\|right\|400px\|[[W:Hydrothermal vent\|Hydrothermal vent]] [[W:biogeochemical\|biogeochemical]] cycle diagram]]
	Salinity dissolved in [[w:seawater\|seawater]] comprises the majority of the know elements including ionic species of chlorine (55%), sodium (30%), sulphate (8%), magnesium (4%) and potassium (1%). Interestingly, throughout the oceans, proportions of these constituents are generally consistent, which indicates that the oceans have mixed well over the millenia, even between the oceans, beyond the semi-contained mixing of the thermohaline circulation.		Salinity dissolved in [[Wikipedia:seawater\|seawater]] comprises the majority of the know elements including ionic species of chlorine (55%), sodium (30%), sulphate (8%), magnesium (4%) and potassium (1%). Interestingly, throughout the oceans, proportions of these constituents are generally consistent, which indicates that the oceans have mixed well over the millenia, even between the oceans, beyond the semi-contained mixing of the thermohaline circulation.

	Ocean chemistry is a result of various biological and geological processes. Much of the ocean's mineral makeup is the result of landward erosion, where freshwaters carry minerals down from hilly landlocked regions into the oceans as erosion. The decay and disintegration of calcium shells and bones also plays a role in adding salinity to seawater. Submarine volcanism often contributes to salinity too, by spewing mineral ejecta into solution within the benthic environs. Lastly but not least, anthropogenic waste contributes heavily to the varied and dangerous chemistry of the oceans today. [[Mercury]] and [[PCB]] contamination is a fixture in our fisheries and our coastal regions today, and the continued use of environmentally destructive industrial processes threatens the future viability of the oceans as a food source.		Ocean chemistry is a result of various biological and geological processes. Much of the ocean's mineral makeup is the result of landward erosion, where freshwaters carry minerals down from hilly landlocked regions into the oceans as erosion. The decay and disintegration of calcium shells and bones also plays a role in adding salinity to seawater. Submarine volcanism often contributes to salinity too, by spewing mineral ejecta into solution within the benthic environs. Lastly but not least, anthropogenic waste contributes heavily to the varied and dangerous chemistry of the oceans today. [[Mercury]] and [[PCB]] contamination is a fixture in our fisheries and our coastal regions today, and the continued use of environmentally destructive industrial processes threatens the future viability of the oceans as a food source.

	The oceans can also be extremely [[w:caustic\|caustic]] requiring structures within them to employ [[w:cathodic protection\|cathodic protection]] from [[w:redox reactions\|redox reactions]]. The vulnerability of materials to seawater may be gauged by referring to its [[w:galvanic potential\|galvanic potential]]. This is why Naval ships are constantly repainted over and over again; to maintain their integrity against the biting seas.		The oceans can also be extremely [[Wikipedia:caustic\|caustic]] requiring structures within them to employ [[Wikipedia:cathodic protection\|cathodic protection]] from [[Wikipedia:redox reactions\|redox reactions]]. The vulnerability of materials to seawater may be gauged by referring to its [[Wikipedia:galvanic potential\|galvanic potential]]. This is why Naval ships are constantly repainted over and over again; to maintain their integrity against the biting seas.

	==Assignments==		==Assignments==
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	'''Study guide:'''		'''Study guide:'''
	# Wikipedia article:[[w:Temperature\|Temperature]]		# Wikipedia article:[[Wikipedia:Temperature\|Temperature]]
	# Wikipedia article:[[w:Density\|Density]]		# Wikipedia article:[[Wikipedia:Density\|Density]]
	# Wikipedia article:[[w:Salinity\|Salinity]]		# Wikipedia article:[[Wikipedia:Salinity\|Salinity]]
	# Wikipedia article:[[w:Chemistry\|Chemistry]]		# Wikipedia article:[[Wikipedia:Chemistry\|Chemistry]]
	# Wikipedia article:[[w:Marine geology\|Marine geology]]		# Wikipedia article:[[Wikipedia:Marine geology\|Marine geology]]
	# Wikipedia article:[[w:Oceanography\|Oceanography]]		# Wikipedia article:[[Wikipedia:Oceanography\|Oceanography]]
	# Wikipedia article:[[w:Chemical oceanography\|Chemical oceanography]]		# Wikipedia article:[[Wikipedia:Chemical oceanography\|Chemical oceanography]]
	# Wikipedia article:[[w:Physical oceanography\|Physical oceanography]]		# Wikipedia article:[[Wikipedia:Physical oceanography\|Physical oceanography]]


	[[Category:Marine science]]		[[Category:Marine science]]
	[[Category:Ocean engineering]]		[[Category:Ocean engineering]]

wikademia>Wikademia: Text replace - 'Wikiversity' to 'Wikademia'

2009-04-11T05:08:17Z

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	'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|~~Wikiversity~~ Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''		'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikademia Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''
	{{ntnes}}		{{ntnes}}
	==Lecture==		==Lecture==

wikademia>Wikademia: Text replace - 'RightTOC' to 'ntnes'

2009-04-10T17:05:04Z

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	'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikiversity Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''		'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikiversity Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''
	{{~~RightTOC~~}}		{{ntnes}}
	==Lecture==		==Lecture==

wikademia>Wikademia at 17:57, 4 April 2009

2009-04-04T17:57:48Z

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	'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikiversity Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''		'''Part of the [[Ocean engineering]] course offered by the ''[[Topic:Marine_engineering\|Wikiversity Department of Marine Engineering]]'', ''[[School:Engineering\|School of Engineering]]'' and the ''[[Portal:Engineering and Technology\|Engineering and Technology Portal]]'''''
			{{RightTOC}}
	==Lecture==		==Lecture==

wikademia>Wikademia: 20 revisions

2009-03-29T19:33:17Z

20 revisions

← Older revision	Revision as of 19:33, 29 March 2009
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98.113.183.3: /* Temperature */

2008-12-06T20:43:39Z

Temperature

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	Similarly, the temperature of the ocean is not uniform at all depths. Any swimmer may recognize the temperature differential between the water at the surface, where the sunlight is incident, and that deeper water that is much cooler. At medium depths however, there is a greatly increased temperature differential, and the water below a certain point is much cooler than the water above it. This sharp differential is called the [[w:thermocline\|thermocline]], and is present in most ocean environments, although greater in the tropics and in temperate regions during summer and nearly nonexistent in polar regions. In shallow waters, the cold air of winter can cool the surface so quickly that the water will actually "turn over", reversing the thermocline. The dependence of the thermocline upon salinity and density will be discussed further with those topics.		Similarly, the temperature of the ocean is not uniform at all depths. Any swimmer may recognize the temperature differential between the water at the surface, where the sunlight is incident, and that deeper water that is much cooler. At medium depths however, there is a greatly increased temperature differential, and the water below a certain point is much cooler than the water above it. This sharp differential is called the [[w:thermocline\|thermocline]], and is present in most ocean environments, although greater in the tropics and in temperate regions during summer and nearly nonexistent in polar regions. In shallow waters, the cold air of winter can cool the surface so quickly that the water will actually "turn over", reversing the thermocline. The dependence of the thermocline upon salinity and density will be discussed further with those topics.


	===Density===		===Density===

wikademia>Gustable at 21:01, 5 July 2008

2008-07-05T21:01:42Z

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	[[Category:Marine ~~sciences~~]]		[[Category:Marine science]]
	[[Category:Ocean engineering]]		[[Category:Ocean engineering]]