Archive for the ‘Ocean dynamics’ Category

Clams [credit: Wikipedia]

Clams [credit: Wikipedia]

El Niño and its twin La Niña are under the spotlight this year as climate-watchers hunt for signs of expected activity that seems to have gone largely missing in recent years if compared to, say, the 1990s.

Has the strength of these phenomena changed in modern times? Apparently not.

‘The charts created by the research team suggest that the ENSO cycle does not have a predictable cycle and also that it has not been increasing in strength over the course of the Holocene as others have suggested.’

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Paul’Vaughan posted a link to this plot on the tail end of a long running thread which has dropped off the front page now, so I thought I’s give it prominence today. It’s a ‘food for thought’ starter – the main course will be served as and when Paul has time.

Sun_Wind

It’s all coming together. Both Paul and I have been working on the sunspot integral over the last several years. Back in 2009 I found that by subtracting the average sunspot number at which the ocean neither gains nor loses energy from the monthly value and summing the running total, I could make use of the sunspot integral as a proxy for ocean heat content (OHC).

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From Physorg, news of a new paper  which may shed light on the rapid warming at the end of the last ice age. The young scientists don’t mention Milankovitch cycles in this presser, but these are slow to change in comparison to the rapid deglaciation, so maybe their theory lends something to the story. It does lead me to wonder if the precession cycle might be involved with bringing the oceanic oscillations into synch though.

From SoundonSound.com: Here you can see the original waveforms of the two different kick-drum samples. It's clear that they are drifting in and out of phase with each other. The resulting phase cancellation made it impossible to arrive at a consistent sound, so Mike had to edit them back into phase before processing.

From SoundonSound.com:
Here you can see the original waveforms of the two different kick-drum samples. It’s clear that they are drifting in and out of phase with each other. The resulting phase cancellation made it impossible to arrive at a consistent sound, so Mike had to edit them back into phase before processing.

Synchronization of North Atlantic, North Pacific preceded abrupt warming, end of ice age

A newly published study by researchers at Oregon State University probed the geologic past to understand mechanisms of abrupt climate change. The study pinpoints the emergence of synchronized climate variability in the North Pacific Ocean and the North Atlantic Ocean a few hundred years before the rapid warming that took place at the end of the last ice age about 15,000 years ago.

The study suggests that the combined warming of the two oceans may have provided the tipping point for abrupt warming and rapid melting of the northern ice sheets.

“If we really do cross such a boundary in the future, we should probably take a long-term perspective and realize that change will become the new normal. It may be a wild ride.”

Results of the study, which was funded by the National Science Foundation, appear this week in Science.

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There has been some progress in the greenhouse. On the ‘toy planet’ thread, physicist Tim Folkerts now agrees with me that longwave infra-red radiated from the air towards the surface doesn’t directly heat the ocean but makes it harder for the ocean to cool. In my view this is due to IR radiation from the ocean making the air warm, reducing the temperature differential between ocean and air, slowing the rate of the Sun warmed ocean’s heat loss. Tim says:

LWIR is indeed incapable of “heating” the oceans in the strict sense of the word (net transfer of thermal energy). The best it can do is aid in making it “a far more difficult task escaping” for the energy.

But it’s hard for him to let go of ingrained notions, so his next comment is full of ambiguities, which I have tried to deal with in my followup comment:

Tim Folkerts: The DWIR DOES amount to ~ 330 W/m^2.

Fine, no problem.

This energy DOES get absorbed by the ocean.

In the top few microns, and is soon re-emitted along with an additional ~60W/m^2 IR, upwards.

The ocean IS warmer than it would be without this DWIR from the atmosphere.

But not because it is absorbed and re-emitted from the top few microns of ocean. The thermalisation of IR in the bulk air helps keep the air warm and that warm air slows the sun warmed ocean’s heat loss.

But the reason the air is warm is because the ocean warms it with the energy it emits into it which is absorbed and re-emitted, or conducted to the O2 and N2 in the air, by water vapour (from the ocean) and co2 (mostly from the ocean). Air has very little heat capacity of its own, and is nearly transparent to incoming solar short wave radiation. And this ocean warmed air is usually convecting upwards.

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teacup-stormReuters news  geophysics-data agency:

(Reuters) – Coastal flooding along the densely populated Eastern Seaboard of the United States has surged in recent years, a Reuters analysis has found.

The analysis was undertaken as part of a broader examination of rising sea levels Reuters plans to publish later this year.

For its analysis, Reuters collected more than 25 million hourly tide-gauge readings from nearly 70 sites on the Atlantic, Gulf and Pacific coasts and compared them to NOAA flood thresholds.

As many Americans question the causes and even the reality of climate change, increased flooding is already posing a major challenge for local governments in much of the United States.
[sure will in landlocked States!]

And goes on about climate change and sea level rise and probably being wound up by vested interests.

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Greenhouse effectsFollowing on from our recent debate on the likely extent of the greenhouse effect on Earth, this post will broaden the scope of discussion by allowing consideration of planetary surface temperatures on imaginary worlds. Tim Folkerts proposes a world at the distance from the Sun of our moon (i.e. the same average distance as Earth), with a twist on surface composition:

Konrad,

Just out of curiosity, if I put a ball of water — say a few km in diameter — in some sort of clear plastic baggie to keep it together and prevent evaporation in orbit around the sun @ 1 AU, are you claiming the water inside the baggie will be at least 80 C everywhere?

Or if I put a series of such plastic baggies on the moon to cover the entire surface with water 1 km deep that cannot evaporate, that the surface of the moon would be at or above 80 C everywhere (lets even limit the question to the “tropics” out to ~ 30 degrees N & S to avoid question about what happens at the poles)?

(We could even make the baggie slightly elastic to apply 1 Atm of pressure inward on the ball of water).

____________________________

Tim appears to have misunderstood what Konrad and I are telling him about the atmosphere being a cooling agent rather than a warming agent, and how pressure acts to slow the loss of energy from the oceans via the atmospheric suppression of evaporation and the increased density of a near surface atmosphere, which is not present on his toy planet.

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H/T to talkshop contributor Wayne for this short piece from the physics of sailing blog which tells us that near surface windspeeds have fallen over the last 30 years. However, the evidence in a presentation by Hartwig Volz on seawater emissivity I came across yesterday apparently contradicts this. I’ve becalmed-yachtadded a couple of the relevant plot’s from that below the short article, but do take a look at the whole pdf slideshow. The discussion of wind speed is highly relevant to the whole climate debate, including the fundamentals of ocean-atmosphere interaction, energy balance and surface warming. Recall that Hans Jelbring’s thesis was entitled ‘Wind Controlled Climate‘ . 

The Wind is Dying

Wind speed has significantly decreased in the 29 years from 1979 to 2008. In extreme cases, the wind decrease was a significant 15%. More specifically, the wind decreased at 73% of measuring stations which were 10 meters above the surface (about mast height for many smaller sailboats). The measurements were mostly from Europe, but also from the United States, China and Russia.

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I came across this paper today while searching for the heat capacity of Venus near surface atmosphere, which is actually an ocean-like (in thermodynamic terms) supercritical fluid. It presages Harry Dale Huffman’s ‘rediscovery’ of the lapse rate calculation by four decades. Another paper, much more recent, (Bolmatov et al 2013) contains some theory which raises yet more questions about the reasons for Venus’ high surface temperature. So, greenhouse due to radiative proerties of co2 as Sagan claimed, lapse rate due to gravity and pressure as Nikolov and Zeller maintain, or the thermal properties of supercritical fluids and geothermal energy having a hard time escaping the lower atmosphere? Let the debate recommence!

venustemp1

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finnish2

David Archibald’s prediction for global average temperature 2014-2025

David Archibald’s post at Quadrant.org.au has stirred some interesting debate here at the talkshop. David predicts an imminent and steep drop in regional temperatures as a result of the slowdown in solar activity seen since the descent of solar cycle 23 in 2003. It’s not the first time he has made such predictions. As Nick Stokes pointed out in discussion, Archibald told the Australian senate committee in 2009 that temperature was about to go down at a scary 0.2C per annum. It didn’t happen. But David says it’s different this time, because a decade has passed since solar cycle 23 dropped towards a long minimum, followed by the weak cycle 24 we are currently in. The decadal lag is implied by David Evan’s new hypothesis which identifies a ‘notch filter’ which points to a cycle-long lag between changes in solar activity and the effect becoming visible in the terrestrial response. David goes on to predict that due to Penn and Livingstone’s prediction of a very low sunspot number in cycle 25, we are headed for drastic cooling.

There are several points on which I disagree with David’s analysis, and I’ll cover them below the break.

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While browsing Ian Wilson’s excellent Astro-Climate Connection blog, I found a graphic showing the coincidence of El Nino with the alignment of the Lunar line of nodes (declination cycle) and line of apse (orbital precession), with the Sun. I’ve taken the liberty of adding my Solar – El Nino hypothesis to it: the proposal is that El Nino tends to be initiated as the cycle starts to decline steeply and initiated again at solar minimum as it ‘bottom’s out’. I’ll reproduce Ian’s accompanying text below the break but to get to the point, here’s  the result:

enso-lunisolar

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I’m of the opinion that before getting into the complexity of numerical modelling, it’s wise to put considerable effort into trying to understand the physical processes at work in the climate system, and the origins of the energy flows that drive them. David Evans’ recent series of posts over at Jo Nova’s site have generated a lot of interesting discussion (despite being roundly ignored by Anthony Watts at WUWT), and I think we can shed some light on the ‘mysterious 11yr lag’ between solar input and climate response.

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An interesting series of posts has appeared at Jo Nova’s site. Jo’s husband, David Evans has done some competent analysis work to unravel the observed ~11 yr ‘delay’ in terrestrial climatic response to solar input. Of interest is the obervation that the solar polar magnetic fields are in the process of weakeneing and changing sign near solar maximum. It is suspected that this is connected with the delay. Head on over to read the posts and comment there as well as here.

Figure 6: The amplitudes of the empirical transfer function when the data is restricted in the ways marked (that is, using a subset of the data used to find Figure 5). The black line and the gray zone are as in Figure 5.

BIG NEWS Part I: Historic development — New Solar climate model coming
BIG NEWS Part II: For the first time – a mysterious notch filter found in the climate
BIG NEWS Part III: The notch means a delay
BIG NEWS part IV: A huge leap understanding the mysterious 11 year solar delay

I have made a comment, reproduced below the break.

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oldbrew:

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A very important topic indeed, thanks to Judith Curry for raising it.

Originally posted on Climate Etc.:

by Judith Curry

 . . . suggesting that Dansgaard-Oeschger events resulted from a combination of the effects of sea ice and ice shelves—structures that help define the margins of ice sheets—to account for both the rapid and the slower parts of the cycle.

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Arctic sea ice [image credit: BBC/Getty Images]

Arctic sea ice [image credit: BBC/Getty Images]

The dynamics of ocean waves in polar regions give us important clues about the behaviour of sea ice in those areas, according to researchers.

“The ice floes bend with the waves, and over time you can imagine that this creates fatigue and eventually the ice will fracture. Interestingly, the fractures tend to be perpendicular to the direction of the waves, and to be of even widths.”

Re the Arctic, a related BBC report notes ‘that wave heights are going to change with increasing distance from the ice edge to the land, and that could have more of an impact on ice break-up.’

Could that suggest a ‘feedback effect': greater distance to land = more ice break-up etc.?

BBC report: Ocean waves influence polar ice extent

Research letter:
Storm-induced sea-ice breakup and the implications for ice extent

oldbrew:

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‘The ocean…is by far the dominant reservoir of climate system heat changes’.

An exclusive from Climate Etc.

Originally posted on Climate Etc.:

by Roger A. Pielke Sr., Richard T. McNider, and John Christy

The thing we’ve all forgotten is the heat storage of the ocean – it’s a thousand times greater than the atmosphere and the surface.  – James Lovelock

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Balancing act

Balancing act

A 2010 paper by University College London (UCL) reported:
‘Evidence from ice-core and marine records for the last glacial period and climate models has supported this bipolar seesaw process, but the extent to which its operation is affected by climate conditions and the hydrological cycle remains unclear. This new study, published in February’s Nature Geoscience, shows that the bipolar see-saw was a feature of the penultimate glacial period, but that its operation was also modified by the background climate state.’

http://www.geog.ucl.ac.uk/about-the-department/news/news-archive-2010/february-2010/the-hydrological-cycle-and-the-bi-polar-climate-see-saw

Now a new paper on this topic has appeared.
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CO2 chart [image credit: Wikipedia]

CO2 chart
[image credit: Wikipedia]

Well-known climate expert and global warming sceptic (apologies for the cliche) Dr Roy Spencer has by his own admission stirred up a hornet’s nest here.

It’s a list of ‘skeptical arguments’ (US spelling) that he considers to be erroneous. Without further ado: enjoy (?).

http://www.drroyspencer.com/2014/04/skeptical-arguments-that-dont-hold-water/

Update: some Talkshop commenters seriously question nos. 6 and 7 on the list.

There is a new open access paper published in Environmental Research Letters by Yannick Peings and Gudrun Magnusdottir entitled ‘Forcing of the wintertime atmospheric circulation by the multidecadal fluctuations of the North Atlantic ocean’. It’s another blow to the ‘bad winter weather is caused by us wicked humans’ doom mongers such as Met Office chief scientist Julia Slingo. 

Click for larger image

Click for larger image

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Here we have  two fine scientists who have written an excellent and easily readable paper, well supported by the evidence they cite.

2400-year cycle in atmospheric radiocarbon concentration: bispectrum of 14C data over the last 8000 years
S. S. Vasiliev and V. A. Dergachev

Received: 5 September 2000 – Revised: 6 August 2001 – Accepted: 21 August 2001

c14-halstatt

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From the ‘you couldn’t make this sh1t up… oh, they did’ dept. via Reuters:

Sea level rise has been one of the clearest signs of climate change – water expands as it warms and parts of Greenland and Antarctica are thawing, along with glaciers from the Himalayas to the Alps.

But in a puzzle to climate scientists, the rate slowed to 2.4 millimeters (0.09 inch) a year from 2003 to 2011 from 3.4 mm from 1994-2002, heartening skeptics who doubt that deep cuts are needed in mankind’s rising greenhouse gas emissions.

Writing in the journal Nature Climate Change on Sunday, experts said the rate from 2003-2011 would have been 3.3 mm a year when excluding natural shifts led by an unusually high number of La Nina weather events that cool the surface of the Pacific Ocean and cause more rain over land.

“There is no slowing in the rate of sea level rise” after accounting for the natural variations, lead author Anny Cazenave of the Laboratory for Studies in Geophysics and Spatial Oceanography in Toulouse, France, told Reuters.

In La Nina years, more rain fell away from oceans, including over the Amazon, the Congo basin and Australia, she said. It is unclear if climate change itself affects the frequency of La Ninas.

Rainfall over land only temporarily brakes sea level rise.

“Eventually water that falls as rain on land comes back into the sea,” said Anders Levermann, a professor at the Potsdam Institute for Climate Impact Research, who was not involved in the study. “Some of it goes into ground water but most of it will drain into rivers, or evaporate.”

HIATUS IN WARMING

The apparent slowing of sea level rise coincided with what the U.N. panel of climate experts calls a hiatus in global warming at the Earth’s surface, when temperatures have risen less sharply despite record emissions of greenhouse gases.

“The slowdown in sea level rise … is due to natural variability in the climate and is not indicative of a slowdown in the effects of global warming,” Nature Climate Change said.

Many scientists suspect that the “missing heat” from a build-up greenhouse gases in the atmosphere is going into the deep oceans as part of natural variations in the climate.

But, because water expands as it warms, that theory had been hard to reconcile with the apparent slowdown in sea level rise.

Read the full story