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Tuesday, March 30, 2010

March 29 - Gulf Stream 'is not slowing down'‏

Dear Friends,

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http://news.bbc.co.uk/2/hi/science/nature/8589512.stm

Be Well.

David

Gulf Stream 'is not slowing down'

By Richard Black
Environment correspondent, BBC News

Argo float being deployed
Data came from the global network of Argo floats in the oceans

The Gulf Stream does not appear to be slowing down, say US scientists who have used satellites to monitor tell-tale changes in the height of the sea.

Confirming work by other scientists using different methodologies, they found dramatic short-term variability but no longer-term trend.

A slow-down - dramatised in the movie The Day After Tomorrow - is projected by some models of climate change.

The research is published in the journal Geophysical Research Letters.

The stream is a key process in the climate of western Europe, bringing heat northwards from the tropics and keeping countries such as the UK 4-6C warmer than they would otherwise be.

It forms part of a larger movement of water, the Atlantic Meridional Overturning Circulation, which is itself one component of the global thermohaline system of currents.

Between 2002 and 2009, the team says, there was no trend discernible - just a lot of variability on short timescales.

The Atlantic overturning circulation is still an important player in today's climate
Josh Willis, Nasa

The satellite record going back to 1993 did suggest a small increase in flow, although the researchers cannot be sure it is significant.

"The changes we're seeing in overturning strength are probably part of a natural cycle," said Josh Willis from Nasa's Jet Propulsion Laboratory (JPL) in California.

"The slight increase in overturning since 1993 coincides with a decades-long natural pattern of Atlantic heating and cooling."

Short measures

The first observations suggesting the circulation was slowing down emerged in 2005, in research from the UK's National Oceanography Centre (NOC).

Using an array of detectors across the Atlantic and comparing its readings against historical records, scientists suggested the volume of cold water returning southwards could have fallen by as much as 30% in half a century - a significant decline.

The surface water sinks in the Arctic and flows back southwards at the bottom of the ocean, driving the circulation.

However, later observations by the same team showed that the strength of the flow varied hugely on short timescales - from one season to the next, or even shorter.

But they have not found any clear trend since 2004.

Global thermohaline circulation
The global thermohaline circulation takes warm and cold water across the oceans

Rapid relief

The NOC team now has a chain of instruments in place across the Atlantic, making measurements continuously.

"In four-and-a-half years of measurement, we have found there is a lot of variability, and we're working to explain it," said NOC's Harry Bryden.

The quantities of water involved are huge, varying between four million and 35 million tonnes of water per second.

The array is part of the UK-funded Rapid project, which aims to refine understanding of potentially large climate change impacts that could happen in short periods.

Professor Bryden's team calculates that their system is good enough to detect a long-term change in flow of about 20% - but it has not happened yet.

He believes the JPL approach - using satellite altimeters, instruments that can measure sea height precisely, and the Argo array of autonomous floating probes - could potentially add useful data to that coming from long-term on-site monitoring arrays.

But, he points out: "The method concentrates only on the upper [northward] flow - it doesn't give you much information on the returning flow southward."

Fantasy and reality

Driven by Hollywood, a popular image of a Gulf Stream slowdown shows a sudden catastrophic event driving snowstorms across the temperate lands of western Europe and eastern North America.

That has always been fantasy - as, said Josh Willis, is the idea that a slow-down would trigger another ice age.

"But the Atlantic overturning circulation is still an important player in today's climate," he added.

"Some have suggested cyclic changes in the overturning may be warming and cooling the whole North Atlantic over the course of several decades and affecting rainfall patterns across the US and Africa, and even the number of hurricanes in the Atlantic."

Richard.Black-INTERNET@bbc.co.uk

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esoteric



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How to Digitally Record/Video a UFO sighting:


Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:




Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.

MUFON.COM

ESOTERIC



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