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Variation of sea water temperature as a function of air, and solar intensity

  1. Jul 27, 2011 #1

    During daytime sea water having poor solar reflectivity remains warmer than the air.

    But at times, water has also been found to be colder than air, with the difference being 5-10 degrees C.
    Can anyone please justify how could that be possible?
  2. jcsd
  3. Jul 27, 2011 #2


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    Often even much more (like 20C). Water temperature is just pretty stable, due to its large heat capacity (except very shallow waters). Due to ocean currents sea temperature may be higher (e.g. Gulfstream at European coast) or colder (Canary stream at Western Africa coast) than average.

    Air gets its temperature very quickly from the ground - and keeps it often even hundred miles from the shore as it is blowed by wind over the sea.

    In a Summer over Arctic Sea shore you quite often may find air at above 20C and sea water just above 0C.
  4. Jul 27, 2011 #3
    Thanks for your response.
    So there could be a major difference in temperature between the two mediums, at the same time and same location.
    Any guesses on what could be the maximum value of difference?
  5. Jul 27, 2011 #4


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    I don't know the Guiness book record - I'm not a meteorologist, but locally it must be really high. E.g. at Antarctica shore, or Siberian/Arctic Sea, if wind blows from the continent (at -50C or so) over open sea (just above 0C).
    Or at Namibian shore, if the wind warmed to +50C over sunny desert goes over the sea cooled by Antarctic Benguela current to +15C or so.

    Anyway - in such condition 'air temperature' is not well defined. You'll get much different results if you measure it 1m above the sea, at the deck of your large ship, or at top of its stem.
  6. Jul 27, 2011 #5
    Thanks again.
    I am trying to plot temperature distribution in a ship for worst case climatic conditions..
    This was really helpful..
  7. Jul 27, 2011 #6
    I have heard that when a ship sailing in atlantic, enters gulf stream the temperature of sea water could drop by 5 to 6 C in an hour's journey or so.

    Do u have information on any such conditions?
  8. Jul 27, 2011 #7


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    You may find (google them!) many services providing sea temperature data (e.g. US Navy).

    I don't know about entering Gulfstream, what you quotes seems reasonable (regarding that temp raises, not drops, as you enter it), but even if you sail small fishing boat along the shore the water temperature may change by 10C or so on few hundred yards - e.g. as you enter waters brought by some river (that's a case of e.g. northern Norwegian shore during Spring - the ocean has 15C or so, warmed by Gulfstream, while water at fjords and fjord mouths has below 5C, as is supplied by melting snow).
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