Antártida

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Re:Antártida
« Respuesta #1152 en: Miércoles 02 Agosto 2017 23:34:23 pm »
Interesante artículo: https://link.springer.com/article/10.1007/s40641-017-0068-8

"An explanation for the temperature changes in both the surface and abyssal Southern Ocean, and the expansion of Antarctic sea ice focusing on an internal mode of ocean variability, has been put forward by Latif et al. [50] on the basis of the Kiel Climate Model (KCM; [75]). The hypothesis, which may be regarded as a null hypothesis, relies on deep-convection variability in the Southern Ocean, specifically in the Weddell Sea. Martin et al. [76] describe a quasi-oscillatory centennial-scale mode of open-ocean deep convection in the KCM with temperature changes of opposite sign at the surface and in the deep Southern Ocean. For example, periods of no deep convection in the Weddell Sea go along with anomalously cold SSTs and anomalously warm temperatures in the middle and deep Southern Ocean and with enhanced sea ice extent. During the convective state, the signs of the anomalies are reversed.

(...)

During phases of deep convection, the heat is rapidly released to the atmosphere, similar to what was observed during the Weddell Polynya [82]. This was a major climatic event with the occurrence of a very large region (350,000 km2) of open water or polynya within the ice-covered Weddell Sea during the austral winters of 1974–1976. It resulted in the convective overturning of the water column and formation of vast amounts of cold and dense AABW [83, 84]. Similarities of the deep-convection phase of the centennial-scale oscillation in the KCM to the Weddell Sea polynya observed in the mid-1970s are noticed by Martin et al. [76]. On the basis of the model results, the Weddell Sea polynya could be part of a longer-term cycle in Southern Ocean deep convection and heat content.

(...)

The studies with the KCM support the conjecture that internal decadal to centennial variability originating in the Southern Ocean did contribute to the observed SST, sea level pressure, sea ice extent, and abyssal temperature trends during the recent decades. "


Teorías.

Saludos

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Re:Antártida
« Respuesta #1154 en: Viernes 15 Septiembre 2017 09:45:21 am »
https://wattsupwiththat.com/2017/08/14/scientists-discover-91-volcanoes-below-antarctic-ice-sheet/

Por fin hay evidencias reales de éste viejo tema de las erupciones en la Antártida:
The First Solid Evidence of Eruptions Under Antarctic Ice
https://www.nature.com/articles/s41598-017-11515-3
http://www.realclearscience.com/quick_and_clear_science/2017/09/14/the_first_solid_evidence_of_eruptions_under_antarctic_ice.html
By Ross Pomeroy
September 14, 2017

In August, researchers at Edinburgh University announced that frigid West Antarctica is home to at least 138 volcanoes, all concealed within an ice sheet that’s up to two kilometers thick in some places!

The finding left Robert Bingham, one of the study’s authors, with an urgent question.

“The big question is: how active are these volcanoes? That is something we need to determine as quickly as possible,” he told The Guardian.

“If one of these volcanoes were to erupt it could further destabilise west Antarctica’s ice sheets. Anything that causes the melting of ice – which an eruption certainly would – is likely to speed up the flow of ice into the sea.”

Luckily, Bingham didn’t need to wait long for an answer. A team of scientists from New Mexico Tech, Dartmouth College, and Vermont Technical College has uncovered evidence of volcanic eruptions in ice cores taken from the West Antarctic ice sheet (WAIS). A paper describing their findings has just been published in Scientific Reports.

Nels Iverson, a PhD Candidate in Geochemistry, and his team examined an ice core situated near two known volcanoes in the ice sheet, Mount Thiel and Mount Resnick. Utilizing scanning electron microscopy and electron microprobe analysis, they found thick layers in the ice core dating back 22.3 thousand years and 44.8 thousand years. These layers were filled with tephra, rock fragments and particles ejected by volcanic eruptions (see figure below).

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Re:Antártida
« Respuesta #1155 en: Miércoles 20 Septiembre 2017 00:50:53 am »
Habemus polynya en el mar de Weddell:


https://nsidc.org/arcticseaicenews/2017/09/arctic-sea-ice-at-minimum-extent-2/
"Beginning around September 2, an opening in the Antarctic sea ice pack formed north of Dronning Maud Land in the easternmost Weddell Sea (near 64°S, 5°E). By mid-September, this opening, or polynya, had grown to about 12,000 square kilometers (4,600 square miles). This feature has been observed intermittently in the Antarctic pack ice since the first satellite data became available in the 1970s. In 1974, 1975, and 1976, the polynya was much larger, averaging 250,000 square kilometers (96,500 square miles). It was absent for many years in the 1980s and 1990s. In recent years the feature has been observed sporadically and has been much smaller.

The polynya is formed when ocean currents uplift deep warm ocean water to the surface where it melts the sea ice. An oceanic plateau called the Maud Rise is responsible for forcing the vertical movement of the water. The persistence of certain atmospheric patterns, such as the southern annular mode, or SAM, is thought to play a role in driving the deep water layer against the Maud Rise.
"



http://mallemaroking.org/weddell-sea-polynya-winter-2017/


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Re:Antártida
« Respuesta #1156 en: Lunes 02 Octubre 2017 20:09:02 pm »
Habemus polynya en el mar de Weddell:


https://nsidc.org/arcticseaicenews/2017/09/arctic-sea-ice-at-minimum-extent-2/
"Beginning around September 2, an opening in the Antarctic sea ice pack formed north of Dronning Maud Land in the easternmost Weddell Sea (near 64°S, 5°E). By mid-September, this opening, or polynya, had grown to about 12,000 square kilometers (4,600 square miles). This feature has been observed intermittently in the Antarctic pack ice since the first satellite data became available in the 1970s. In 1974, 1975, and 1976, the polynya was much larger, averaging 250,000 square kilometers (96,500 square miles). It was absent for many years in the 1980s and 1990s. In recent years the feature has been observed sporadically and has been much smaller.

The polynya is formed when ocean currents uplift deep warm ocean water to the surface where it melts the sea ice. An oceanic plateau called the Maud Rise is responsible for forcing the vertical movement of the water. The persistence of certain atmospheric patterns, such as the southern annular mode, or SAM, is thought to play a role in driving the deep water layer against the Maud Rise.
"



http://mallemaroking.org/weddell-sea-polynya-winter-2017/


En el fondo ésto  es como abrir una válvula de alivio de presión - el océano luego libera un exceso de calor a la atmósfera durante varios inviernos consecutivos hasta que el depósito de calor se agota. Realmente los científicos norteamericanos aseguraron que con el calentamiento global ésto no volvería a ocurrir y  la polynya hay que verla como una parte de la variabilidad natural a largo plazo.

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Re:Antártida
« Respuesta #1157 en: Lunes 09 Octubre 2017 11:36:22 am »
Cómo se encuentra el iceberg de Larsen C (A 68) en éstos momentos?

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Re:Antártida
« Respuesta #1158 en: Lunes 09 Octubre 2017 11:50:58 am »
Mapa de concentración y  SST.
Sigue  más menos como el 6º valor más bajo de la serie con 17,99 millones de km2

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Re:Antártida
« Respuesta #1159 en: Jueves 16 Noviembre 2017 08:00:29 am »
New map of Antarctic geothermal heat suggests Steig & Mann 2009 weren’t measuring ‘global warming’

An international team of scientists, led by British Antarctic Survey (BAS), has produced a new map showing how much heat from the Earth’s interior is reaching the base of the Antarctic Ice Sheet. The map is published this week (Monday 13 November) in the journal Geophysical Research Letters.
The team has produced the most up to date, accurate and high-resolution map of the so-called ‘geothermal heat flux’ at the base of the Antarctic Ice Sheet. Of the basic information that shapes and controls ice flow, the most poorly known about is this heat.
Yes there’s warming in West Antarctica and the Peninsula, but is CO2 the cause? This new geothermal heat flux data and study from BAS throws ice water on that idea.
The new study from BAS uses over 50 years of magnetic measurements that were collected from thousands of hours flying over the continent. Warmer rocks lose their magnetic properties, and so the team was able to use the loss of magnetism in certain areas to calculate an estimate of the geothermal heat flux.
And gosh, side by side, these two maps look strikingly similar in the “hot spot” areas on the Antarctic Peninsula, and West Antarctica:




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:viejito: Heber Rizzo
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Yo mismo

Green power, black death
Paul Driessen

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Re:Antártida
« Respuesta #1160 en: Jueves 16 Noviembre 2017 19:54:45 pm »
La NASA halla más pruebas de la existencia de una fuente de calor bajo la Antártida

http://www.abc.es/ciencia/abci-nasa-aporta-nuevas-pruebas-existe-fuente-calor-bajo-antartida-201711101127_noticia.html
Lo que hacemos en esta vida tiene su eco en la eternidad.

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Re:Antártida
« Respuesta #1161 en: Martes 28 Noviembre 2017 11:13:48 am »
Antartida:

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Re:Antártida
« Respuesta #1162 en: Martes 12 Diciembre 2017 02:11:09 am »
Esa grafica pica para abajo... interesante  :brothink: :brothink:
Oviedo (333m), en la parte oeste de la ciudad, zona alta.
Vigo de Sanabria (1103m), en la montaña Zamorana, pegado a Orense y Portugal.

Seguimiento de polos del frío en León, Zamora y Asturias.
Proyecto Jous de Picos: https://proyectojouspicos.wordpress.com/

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Re:Antártida
« Respuesta #1163 en: Sábado 16 Diciembre 2017 13:30:13 pm »
Five Years Of Antarctic Temperature Fraud At NASA

In 2004, Gavin Schmidt reported decades of significant cooling over Antarctica.
In 2005, NASA published a map showing the cooling.
By 2007, NASA had completely erased the cooling.
And by 2009, NASA had turned all the cooling into warming.




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:viejito: Heber Rizzo
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Yo mismo

Green power, black death
Paul Driessen

Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
Albert Einstein