Massive cold region in the North Atlantic Ocean

  • Thread starter dorlomin
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  • #1
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sst_anom.gif


Can anyone explain to me the cause of this massive cold water region in the north atlantic.

Is it winds stirring up cold deep water (ekman wind?)

Is it a natural variation in currents bringing colder water to the surface?

Is there any relationship to the regions north and south of it being warmer?
 

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  • #2
Kerrie
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No idea, but the first thought that came to mind was, how deep is the ocean in those cold spots?
 
  • #3
matthyaouw
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Don't know, but it's worth keeping in mind that the map shows temperature anomaly, not temperature. It shows how much colder or warmer an area was on the 5th of june compared to the average (what average I don't know...)

It could be as simple as an area of unusually persistent cloud cover keeping sunlight off the water so allowing it to cool a few degrees.
 
  • #4
Xnn
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That map is misleading, since the zero is a color as opposed to being a neutral gray or white.
Compare it to the NCDC map:

http://www.ncdc.noaa.gov/oa/climate/research/sst/weekly-sst.php [Broken]

You'll see that while their is a cold region in the Atlantic, it's dwarfed by several larger warm area.

Also consider that in April the global sea surface temperature was at a record high for the month.


  • The combined global land and ocean average surface temperature for April 2010 was the warmest on record at 14.5°C (58.1°F), which is 0.76°C (1.37°F) above the 20th century average of 13.7°C (56.7°F). This was also the 34th consecutive April with global land and ocean temperatures above the 20th century average.
  • The worldwide ocean surface temperature was 0.57°C (1.03°F) above the 20th century average of 16.0°C (60.9°F) and the warmest April on record. The warmth was most pronounced in the equatorial portions of the major oceans, especially the Atlantic.
  • The April worldwide land surface temperature was 1.29°C (2.32°F) above the 20th century average of 8.1°C (46.5 °F)—the third warmest on record.
  • For the year-to-date, the global combined land and ocean surface temperature of 13.3°C (56.0°F) was the warmest January-April period. This value is 0.69°C (1.24°F) above the 20th century average.

The cold region is probably caused by weather conditions. Not sure how long it will persist, but it hasn't been there for a long term climatologically.
 
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  • #5
Gokul43201
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sst_anom.gif


Can anyone explain to me the cause of this massive cold water region in the north atlantic.

Is it winds stirring up cold deep water (ekman wind?)

Is it a natural variation in currents bringing colder water to the surface?

Is there any relationship to the regions north and south of it being warmer?
Can you provide the url for the page where this appears?

And how does the date stamp make any sense?

EDIT: I guess it's possible the same url is used for updated images?

EDIT 2: Yes, it is.
 
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  • #7
Gokul43201
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Paul, thanks for the response. I know what the url for the image itself is. I was looking for the url for a page where that image appears within context - a page with some discussion of the dataset/analysis.

This is the page: http://weather.unisys.com/surface/sst_anom.html

But unfortunately, there is no discussion there.
 
  • #8
Evo
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This might explain it.

The same negative NAO/AO pattern responsible for the cold GOM has also had effects across the entire north Atlantic. With arctic air being shoved down into the mid-latitudes all winter, this greatly enhanced the positive Atlantic tripole. The Atlantic tripole is a pattern that likes to show itself during warm AMOs where you have warm water in the tropics, cold water in the mid-latitudes, and warm water again in the arctic areas of the Atlantic north of 50N. The cold winter has served to enhance and expand the cold water belt north of 30N, which can be seen in the image above as an area of blue anomalies in the north Atlantic, smaller now due to the recent warming off the SE US.
The image referenced is the cold water anomaly in the North Atlantic Ocean.

Seasonal variations now start to play a key role, as during the winter and springtime, this belt of cold water sets up a strong temperature gradient with the warmer water to the south, resulting in a strong baroclinic zone along the gradient which pulls the subtropical jetstream to the south, creating a positive feedback with the negative NAO. This has favored lower-than-normal pressures in the northeast Atlantic during the winter and spring months, which slows the easterly trade winds over the tropics. In the summer, when the jet retreats to the north, the baroclinic zone dissapears, and the pattern switches so that the lowest pressures are found in the southwest Atlantic over warm tropical waters.

This is the kind of thing that will happen this summer as we have a classic setup of cold over warm in the Atlantic, where the cold water to the north promotes net subsidence (sinking air), and the warm water to the south promotes net upward motion. This really focuses heat and convergence over the deep tropical breeding grounds, lowering surface pressures and favoring lots of storm activity.
http://www.wunderground.com/blog/Levi32/comment.html?entrynum=268
 

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