Le Gulf Stream a été en panne pendant 10 jours en novembre 2004

[Invité]

Ave voisin corse. lis-tu dans les pensées ?

Car au lieu d'invoquer la famille sacrée

J'ai été sur le point d'avouer ma Mission

Que sans entrave nous défendions notre Maison.

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Mais ce sont de véritables bout-en-train ces corses! /emoticons/biggrin@2x.png 2x" width="20" height="20">

Et de véritables poètes qui plus est!

Mais en tous cas c'est de bonne facture et çà détend.

congratulations! /emoticons/wink@2x.png 2x" width="20" height="20">

[gerardlh]

eh finalement à lire les derniers messages Gombervaux vous avez raison. /emoticons/smile@2x.png 2x" width="20" height="20">/emoticons/biggrin@2x.png 2x" width="20" height="20">

G S : génie scientifique... /emoticons/biggrin@2x.png 2x" width="20" height="20">/emoticons/wink@2x.png 2x" width="20" height="20">

[Pierre-Ernest]

Voici qui clot le débat : RealClimate

Il est très intéressant de remonter dans les échanges sur ce sujet.

[lc30]

Voici qui clot le débat : RealClimate

Il est très intéressant de remonter dans les échanges sur ce sujet.

oui absolument et pour bien enfocer le clou j'en tire cette citation, en soulignant trois mots

"Other results presented supported this basic picture: transport estimates at different latitudes were not coherent with the initial results, model variability in the best ocean models was large (suggesting that detectability of a MOC slowdown before 2030-2050 was unlikely), and temperature, salinity and velocity changes in the overflow waters between Greenland and Europe showed significant connections to the North Atlantic Oscillation but no obvious trends. A number of records that had seemed to be trending strongly when first looked at, now seem to be simply more variable than first thought. This was something of a theme at the conference - the closer we look at the ocean, the more dynamic it appears. "

par contre, sous l'effet d'une séismicité de grande ampleur et très fréquente ( plusieurs M6 voire M7 par an) dans des zones précises de faible ou de très faible profondeur ( moins de 50 mètres) donc sensibles aux surrections et subsidences liées à la séismicité : détroit de Torrès, détroit de Behring, là il y a certainement des échanges interocéan iques qui se font différemment.

Et pour l'Est de Torrès ne pas oublier la grande barrière de corail...

--

lc30

[charles.muller]

Dans Science cette semaine, dernières nouvelles de la THC : à la conférence RAPID de la fin du mois dernier, Bryden lui-même admet que les amplitudes naturelles de la THC sont plus importantes que prévues, et comparables sur une année à la tendance qu'il avait cru déceler sur plusieurs décennies. Pas d'affaiblissement de la THC en vue, donc, et sans doute pas d'interprétations fiables avant quelques décennies de mesure.

On appréciera à nouveau la grande précision journalistique du Guardian

Science 17 November 2006:

Vol. 314. no. 5802, p. 1064

News of the Week

GLOBAL CLIMATE CHANGE:

False Alarm: Atlantic Conveyor Belt Hasn't Slowed Down After All

Richard A. Kerr

A closer look at the Atlantic Ocean's currents has confirmed what many oceanographers suspected all along: There's no sign that the ocean's heat-laden "conveyor" is slowing. The lag reported late last year was a mere flicker in a system prone to natural slowdowns and speedups. Furthermore, researchers are finding that even if global warming were slowing the conveyor and reducing the supply of warmth to high latitudes, it would be decades before the change would be noticeable above the noise.

The full realization of the Atlantic's capriciousness comes with the first continuous monitoring of the ocean's north-south flows. In March 2004, researchers of the Rapid Climate Change (RAPID) program moored 19 buoyant, instrument-laden cables along 26.5°N from West Africa to the Bahamas. A few months later, they steamed along the same latitude, lowering instruments periodically to take an instantaneous "snapshot" of north-south flows. While waiting for the moored array to produce long-term observations, physical oceanographer Harry Bryden and his team at the National Oceanography Centre in Southampton, U.K., compared the 2004 snapshot with four earlier instantaneous surveys dating back to 1957. They found a 30% decline in the northward flow of the conveyor (Science, 2 December 2005, p. 1403), sparking headlines warning of Europe's coming ice age.

The first year of RAPID array observations has now been analyzed, and the next European ice age looks to be a ways off. At a RAPID conference late last month in Birmingham, U.K., Bryden reported on the first continuous gauging of conveyor flow. Variations up and down within 1 year are as large as the changes seen from one snapshot to the next during the past few decades, he found. "He observed a lot of variability," says oceanographer Martin Visbeck of the Leibniz Institute of Marine Science at the University of Kiel in Germany, who attended the meeting; so much variability that "more than 95% of the scientists at the workshop concluded that we have not seen any significant change of the Atlantic circulation to date," wrote Visbeck in a letter to the British newspaper the Guardian.

Although the immediate threat has evaporated, a difficult challenge has taken its place. "Scientific honesty would require records for decades" in order to pick out a greenhouse-induced slowing, says physical oceanographer Carl Wunsch of the Massachusetts Institute of Technology in Cambridge. "How do you go about doing science when you need decades of record?" For their part, RAPID researchers will be asking for funding to extend array operations to a decade, says Bryden. Then some combination of government agencies would have to take on the burden of decades of watchful waiting.