Antartida + pólo sul

Luis França

Nimbostratus
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Alguns dados sísmicos (dia 2.2.2007) do pólo...grandes mudanças no horizonte
:)

Data from station PMSA (Palmer Station, Antarctica)
PMSA_24hr.gif


Data from station PTCN (Pitcairn Island, South Pacific)
PTCN_24hr.gif
 

Luis França

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O drumbeat continua com algumas incongruências...

IU/ULN, Ulaanbaatar, Mongolia
ULN_24hr.gif


IU/TIXI, Tiksi, Russia
TIXI_24hr.gif


IU/RAO, Raoul, Kermandec Islands
RAO_24hr.gif


PTCN (Pitcairn Island, South Pacific)
PTCN_24hr.gif


BILL (Bilibino, Russia)
BILL_24hr.gif
 

Meteo Trás-os-Montes

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Carcavelos /Chaves / Vilardevós - Galiza
Lua e Neptuno

Amigos vi hoje na meteo do canal catalão que hoje é possivel ver neptuno a olho nu por estar mto proximo visualmente da lua... Mas aqui em Lx esta mto nublado... Não se pode ver! :(:sad:
 

Rog

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Norte Madeira (500m)
Re: Lua e Neptuno

Amigos vi hoje na meteo do canal catalão que hoje é possivel ver neptuno a olho nu por estar mto proximo visualmente da lua... Mas aqui em Lx esta mto nublado... Não se pode ver! :(:sad:

Neptuno???? Só se tiveres grande acuidade visual e mesmo assim dificilmente...
O nosso limite de magnitude a olho nu, e tem de ser em noite bem escura sem lua, é de 6. Neptuno tem mag. 8. Só com binóculos e mesmo assim, a melhor hipotese será um simples telescópio.
Nem Urano, que está no limite mag. 5,9, mas mesmo este é necessário binóculos, e saber reconhecer um pouco o ceu para o encontrar...
Eles deviam estar a se referir a Saturno que vai com mag. 0, e durante esta noite estava um pouco à frente da Lua.
Já agora, logo após o por-do-sol é visível a conhecida "estrela da tarde", que não é estrela mas sim o Planeta Vénus.
 

Luis França

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Ocean heat blamed for the mysterious disappearance of glaciers

A mysterious phenomenon is causing four major glaciers in the Antarctic to shrink in unison, causing a significant increase in sea levels, scientists have found.

The rise in atmospheric temperatures caused by global warming cannot account for the relatively rapid movement of the glaciers into the sea, but scientists suspect that warmer oceans may be playing a role.

"There is a possibility that heat from the ocean is somehow flowing in underneath these glaciers, but it is not related to global warming," said glaciologist Duncan Wingham of University College London. "Something has changed that is causing these glaciers to shrink.

[link]
 

Luis França

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Antarctic Glaciers' Sloughing Of Ice Has Scientists at a Loss

Some of the largest glaciers in Antarctica and Greenland are moving in unusual ways and are losing increased amounts of ice to the sea, researchers said yesterday.

Although the changes in Greenland appear to be related to global warming, it remains unclear what is causing the glaciers of frigid Antarctica and their "ice streams" to lose ice to the ocean in recent years, the researchers said.

[link]
 

Luis França

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Wilkins Ice Shelf collapses

A 14,000 square km shelf of ice, almost twice the area of the Basque Country, has broken off the Wilkins Ice Shelf in the Antarctic. Scientists believe the ice shelf is crumbling as a result of global warming.

The Spanish National Research Council (CSIC) has reported today that the resulting giant icebergs are now floating around in the Antarctic Ocean.

A team of CSIC scientists have been in the area investigating the impact of the crumbling ice shelf on the ecosystem in the Belinghausen Sea, to the west of the Antarctic peninsula.

Over the past two weeks, the scientists have seen the ice shelf on the edge of the Belinghausen Sea recede 550km and have noted that the water temperatures are extraordinarily warm in this area.

Experts have warned that the breaking away of this massive ice shelf will ultimately have notable consequences on the sea level.

CSIC scientist, Jordi Dachs, reported that his team had found 'a very high level of biological production' in the areas where the fragments of ice have gone and that there is 'abundant fauna, with the largest concentration of humpback whales and leopard seals' they have seen up until now.

'We have also found very low levels of CO2 in the sea water' he continued, 'suggesting that the increase in sunlight getting through and the elements released by the breaking ice fertilise the water'.

Pedro Luis de la Puente, captain of the BIO Hespérides the scientists are working from, underlined the dangers of navigating in these areas, which have 'never had a full topographical survey as they have been covered in ice up until now'. The water is thought to be between 150 and 300 metres deep and the scientists are encountering icebergs that have run aground, suggesting that they could be approximately 200 metres thick.

In the past 50 years, Antarctica has seen the greatest temperature increase across the whole planet: 0.5 degrees centigrade per decade, and the area is seeing a dramatic loss of ice, much greater even than scientists had anticipated.



Ice shelf collapse could shift axis of Earth, study says


450_icesheet_090205.jpg


A new study from Toronto researchers suggests that the collapse of a large portion of the Antarctic ice sheet would shift the very axis of the Earth.
Geophysicists at the University of Toronto explored the effects on North America and the globe, if sea levels were to rise due to the collapse of the West Antarctic Ice Sheet.
One of the most jarring predictions contained in the report, to be published in the Feb. 6 issue of the journal Science, is that the sea-change could shift the Earth's rotation.
"The melting of the West Antarctic Ice Sheet will actually cause the Earth´s rotation axis to shift rather dramatically -- approximately 500 metres from its present position if the entire ice sheet melts," states a release from U of T's physics department.
There is a widespread belief among scientists that the ice sheet is especially vulnerable to rising global temperatures, and may be prone to collapse, which could trigger a rise in sea levels.
Some analysts have predicted sea levels will rise by five metres -- a value arrived at by taking the total volume of the ice sheet, converting it to water and spreading it evenly across the globe's oceans.
But the new report suggests that is too simplistic an approach, and some areas -- North America and nations in the southern Indian Ocean in particular -- would see much higher sea-level rises than other areas.
"We´ve been able to calculate that not only will the rise in sea levels at most coastal sites be significantly higher than previously expected, but that the sea-level change will be highly variable around the globe," said physics graduate student Natalya Gomez.
The research suggests the melting of the sheet would change the balance of the globe -- similar to tsunamis that move massive amounts of water from one area to another.
Water would migrate from the southern Atlantic and Pacific Oceans northward toward North America and into the southern Indian Ocean.
"The net effect of all of these processes is that if the West Antarctic Ice Sheet collapses, the rise in sea levels around many coastal regions will be as much as 25 per cent more than expected, for a total of between six and seven metres if the whole ice sheet melts," said geophysicist Jerry Mitrovica.
"That´s a lot of additional water, particularly around such highly populated areas as Washington, D.C., New York City, and the California coastline."
The study pointed out three factors that are likely to have an effect on the disbursement of water from the melting shelf.
It suggests that as an ice sheet collapses, water actually moves away from it because the sheet's gravitational pull lessens. The result is that the sea level in the area of the shelf actually drops, while other areas see dramatic increases.
Secondly, the research suggests a massive depression in the bedrock that is currently underneath the ice shelf, will fill with water if the sheet collapses. But as the sheet melts and its weight disperses, the depression will rebound, thereby pushing water into other areas.
Thirdly, the shift in the Earth's rotation will cause water north, towards North America and the Southern Indian Ocean.
The research is to be published in a paper titled "The Sea Level Fingerprint of West Antarctic Collapse."
 

Aristocrata

Super Célula
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Paços de Ferreira, 292 mts
Uma mudança destas poderia lançar-nos num "caos climático". Digo isto sem exageros já que uma mudança destas poderia alterar profundamente o nosso clima actual.
Uma mudança por pequena que seja no eixo da terra poderá trazer algo que os humanos modernos ainda não viram e, penso eu, nunca estudado até agora.
Consequências? Haverão sem dúvida, se tal acontecer, mas a que nível penso que ninguém terá a resposta. Se teremos melhor ou pior clima? Ainda não há respostas...:huh: