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- Johan_Sandström abstract "Johan Wilhelm Sandström (6 June 1874, Degerfors, Västerbotten County – 1947), usually cited as J. W. Sandström, was a Swedish oceanographer.He is most famously known for conducting a series of classical experiments at Bornö oceanographic station in Sweden that were reported in Sandstrom (1908). His experiments concerned themselves with the causes of ocean currents, particularly those found in fjords. Sandstrom was principally concerned with the role of heating and cooling in driving such currents, and in the larger-scale ocean circulation in general.Sandstrom asserted that thermal circulation can cause vigorous, steady circulation only if heating occurs at greater depths than cooling. This is known today as Sandström's theorem. Sandstrom's theorem represents an attempt at extending the well known result of classical thermodynamic theory that in order for a heat engine to perform positive work over a cycle, the work of expansion needs to occur at greater pressure than the work of contraction. Sandstrom's theorem is therefore technically true, as long as expansion in the fluid is caused by heating and contraction by cooling, and that greater depths occur at greater pressures. There is an ambiguity, however, as to the meaning of the terms 'heating' and 'cooling' in Sandstrom's theorem. So far, heating and cooling has always been interpreted in the literature as being associated with 'surface heating' and 'surface cooling' respectively. In real fluids, however, molecular and turbulent diffusion always cause internal heating/cooling even in absence of external heating/cooling, as long as the temperature of the fluid considered is non-uniform. As is well-known, molecular and turbulent diffusion tends to relax the system toward thermodynamic equilibrium, i.e., toward an isothermal state, which for a statically stable fluid, will warm up the fluid at high pressure, and cool it down at low pressure. Therefore, because of internal diabatic heating/cooling by molecular/turbulent diffusion, the overall heating experienced by a stratified fluid always occurs at greater pressure than the total cooling, even if the external cooling/heating occur at the same pressure. As a result, internal diabatic heating/cooling due to molecular diffusion explains why laboratory experiments show evidence of circulations developing as the result of surface heating/cooling (Park and Whitehead, 2000) or even when the heating is above the cooling (Coman et al., 2006). Sandström's key (though not clearly expressed) insight, was that in such circulations, the circulation as a whole must transport light water downwards and dense water upwards. This means that the effect of the circulation is to increase the potential energy. Such an increase requires an external source of energy. Recent work has built on this to argue that the ocean circulation as a whole is driven by these external sources of energy, whether wind or tides, with newer work suggesting that internal sources and sinks of energy (such as those driving diffusion) are also potentially important.In 1925, Sandström was elected a member of the Royal Swedish Academy of Sciences.".
- Johan_Sandström birthDate "1874-06-06".
- Johan_Sandström birthYear "1874".
- Johan_Sandström deathDate "1947".
- Johan_Sandström deathYear "1947".
- Johan_Sandström thumbnail Sandstroem.jpg?width=300.
- Johan_Sandström wikiPageID "1790984".
- Johan_Sandström wikiPageLength "4104".
- Johan_Sandström wikiPageOutDegree "14".
- Johan_Sandström wikiPageRevisionID "660466868".
- Johan_Sandström wikiPageWikiLink Bergen_School_of_Meteorology.
- Johan_Sandström wikiPageWikiLink Bornö.
- Johan_Sandström wikiPageWikiLink Category:1874_births.
- Johan_Sandström wikiPageWikiLink Category:1947_deaths.
- Johan_Sandström wikiPageWikiLink Category:Members_of_the_Royal_Swedish_Academy_of_Sciences.
- Johan_Sandström wikiPageWikiLink Category:Swedish_oceanographers.
- Johan_Sandström wikiPageWikiLink Degerfors.
- Johan_Sandström wikiPageWikiLink Oceanographer.
- Johan_Sandström wikiPageWikiLink Oceanography.
- Johan_Sandström wikiPageWikiLink Royal_Swedish_Academy_of_Sciences.
- Johan_Sandström wikiPageWikiLink Sandstrxc3xb6ms_theorem.
- Johan_Sandström wikiPageWikiLink Sweden.
- Johan_Sandström wikiPageWikiLink Västerbotten_County.
- Johan_Sandström wikiPageWikiLink File:Sandstroem.jpg.
- Johan_Sandström wikiPageWikiLinkText "Johan Sandström".
- Johan_Sandström wikiPageWikiLinkText "Sandström's theorem".
- Johan_Sandström dateOfBirth "1874-06-06".
- Johan_Sandström dateOfDeath "1947".
- Johan_Sandström hasPhotoCollection Johan_Sandström.
- Johan_Sandström name "Sandstrom, Johan".
- Johan_Sandström shortDescription "Swedish oceanographer".
- Johan_Sandström wikiPageUsesTemplate Template:Authority_control.
- Johan_Sandström wikiPageUsesTemplate Template:Persondata.
- Johan_Sandström description "Swedish oceanographer".
- Johan_Sandström description "Swedish oceanographer".
- Johan_Sandström subject Category:1874_births.
- Johan_Sandström subject Category:1947_deaths.
- Johan_Sandström subject Category:Members_of_the_Royal_Swedish_Academy_of_Sciences.
- Johan_Sandström subject Category:Swedish_oceanographers.
- Johan_Sandström type Agent.
- Johan_Sandström type Person.
- Johan_Sandström type Person.
- Johan_Sandström type Agent.
- Johan_Sandström type NaturalPerson.
- Johan_Sandström type Thing.
- Johan_Sandström type Q215627.
- Johan_Sandström type Q5.
- Johan_Sandström type Person.
- Johan_Sandström comment "Johan Wilhelm Sandström (6 June 1874, Degerfors, Västerbotten County – 1947), usually cited as J. W. Sandström, was a Swedish oceanographer.He is most famously known for conducting a series of classical experiments at Bornö oceanographic station in Sweden that were reported in Sandstrom (1908). His experiments concerned themselves with the causes of ocean currents, particularly those found in fjords.".
- Johan_Sandström label "Johan Sandström".
- Johan_Sandström sameAs Johan_Wilhelm_Sandström.
- Johan_Sandström sameAs Johan_Sandström.
- Johan_Sandström sameAs m.05x7d8.
- Johan_Sandström sameAs Johan_Sandström_(oceanograf).
- Johan_Sandström sameAs Q4580435.
- Johan_Sandström sameAs Q4580435.
- Johan_Sandström wasDerivedFrom Johan_Sandström?oldid=660466868.
- Johan_Sandström depiction Sandstroem.jpg.
- Johan_Sandström givenName "Johan".
- Johan_Sandström isPrimaryTopicOf Johan_Sandström.
- Johan_Sandström name "Johan Sandstrom".
- Johan_Sandström name "Sandstrom, Johan".
- Johan_Sandström surname "Sandstrom".