Evidence is Mounting: Oceans Make Climate

Update May 28, 2015, with additional detail from Dr. McCarthy

Update May 29, 2015, with additional context from Bob Tisdale

The RAPID moorings being deployed. Credit: National Oceanography Centre

A new study, by scientists from the University of Southampton and National Oceanography Centre (NOC), implies that the global climate is on the verge of broad-scale change that could last for a number of decades. This new climatic phase could be half a degree cooler.

The change to the new set of climatic conditions is associated with a cooling of the Atlantic, and is likely to bring drier summers in Britain and Ireland, accelerated sea-level rise along the northeast coast of the United States, and drought in the developing countries of the Sahel region. Since this new climatic phase could be half a degree cooler, it may well offer a brief reprise from the rise of global temperatures, as well as resulting in fewer hurricanes hitting the United States.

The study, published in Nature, proves that ocean circulation is the link between weather and decadal scale climatic change. It is based on observational evidence of the link between ocean circulation and the decadal variability of sea surface temperatures in the Atlantic Ocean.

Lead author Dr Gerard McCarthy, from the NOC, said: “Sea-surface temperatures in the Atlantic vary between warm and cold over time-scales of many decades. These variations have been shown to influence temperature, rainfall, drought and even the frequency of hurricanes in many regions of the world. This decadal variability, called the Atlantic Multi-decadal Oscillation (AMO), is a notable feature of the Atlantic Ocean and the climate of the regions it influences.”

The strength of ocean currents has been measured by a network of sensors, called the RAPID array, which have been collecting data on the flow rate of the Atlantic meridonal overturning circulation (AMOC) for a decade.

Dr David Smeed, from the NOC and lead scientist of the RAPID project, adds: “The observations of AMOC from the RAPID array, over the past ten years, show that it is declining. As a result, we expect the AMO is moving to a negative phase, which will result in cooler surface waters. This is consistent with observations of temperature in the North Atlantic.”

http://www.sciencedaily.com/releases/2015/05/150527133932.htm

Some additional detail from Dr. McCarthy:

Results from the RAPID array

Gerard McCarthy, David Smeed, Darren Rayner, Eleanor Frajka-Williams, Aurélie Duchez, Bill Johns, Molly Baringer, Chris Meinen, Adam Blaker, Stuart Cunningham and Harry Bryden

“The RAPID/MOCHA/WBTS mooring array at 26ºN in the Atlantic has been delivering twice daily estimates of the strength of the AMOC since 2004. A unique array, the observations have revolutionised our understanding of the variability of the AMOC on sub-annual, seasonal and, most recently, interannual timescales. An update to the AMOC timeseries has recently been produced.   As well as extending the data, the timeseries to October 2012 contains several improvements to the calculation.

A dramatic low in the AMOC was observed in winter 2009/10, where the AMOC declined by 30%. This has been shown to have resulted in a sustained reduction in heat content of the North Atlantic. The 2009/10 dip in AMOC strength was followed by a second dramatic low in 2010/11. Historical analogues of double minima in successive winters have been identified in NEMO runs where they are associated with extreme negative values of the Arctic oscillation and have been linked with ocean re-emergence. Interestingly, there is also a link with surface air temperatures and, consequently, European wintertime conditions.

The latest update of the AMOC time series to October 2012 shows a continuing trend in the circulation at 26ºN switching from an overturning to a gyre circulation. This leads to weakened southward transport of lower North Atlantic Deep Water, the strength of which from 2004-2012 is weaker than in historical measurements. The IPCC report in 2007 reported that the AMOC was ‘very likely’ to weaken in the 21st century. Maintaining the sustained observations of the RAPID array is key to observing this climate metric.”

Rapid Project Webpage is here: http://www.rapid.ac.uk/rapidmoc/

Figure 1:Ten-day (colours) and three month low-pass (black) timeseries of Florida Straits transport (blue), Ekman transport (black), upper mid-ocean transport (magenta), and overturning transport (red) for the period 2nd April 2004 to mid- March 2014. Florida Straits transport is based on electromagnetic cable measurements; Ekman transport is based on ERA winds. The upper mid-ocean transport, based on the RAPID time series, is the vertical integral of the transport per unit depth down to the deepest northward velocity (~1100 m) on each day. Overturning transport is then the sum of the Florida Straits, Ekman, and upper mid-ocean transports and represents the maximum northward transport of upper-layer waters on each day. Positive transports correspond to northward flow.

Additional info here: http://www.livescience.com/50998-jet-stream-controls-atlantic-climate-cycles.html

Footnote:

Getting a reprieve from the dangers of global warming would be good news, but these facts were not well received by everyone last month at a conference in Vienna, as tweeted by Dr. McCarthy:

Bob Tisdale provides additional context on the AMO and on this paper, as well as critiques of some other papers here: https://bobtisdale.wordpress.com/2015/05/29/new-paper-confirms-the-drivers-of-and-processes-behind-the-atlantic-multidecadal-oscillation/

For more on this topic see:

https://rclutz.wordpress.com/2015/05/10/empirical-evidence-oceans-make-climate/

https://rclutz.wordpress.com/2015/04/13/climate-pacemaker-the-amoc/

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Climate on Ice: Ocean-Ice Dynamics

Update May 30, 2015 Longer term context by E.M. Smith added below

Sea ice is not simple. Some Background is in order.

When white men started to explore the north of America, they first encountered the Crees. Hudson Bay posts were established to trade goods for pelts, especially the beavers used for making those top hats worn by every gentleman of the day.

The Crees told the whites that further on toward the Arctic Circle there were others they called “eskimos”. The Cree word means “eaters of raw meat” and it is derogatory. The Inuit (as they call themselves) were found to have dozens of words for snow, a necessary vocabulary for surviving in the Arctic world.

A recent lexicon of sea ice terminology in Nunavik (Appendix A of the collective work Siku: Knowing our Ice, 2008) comprises no fewer than 93 different words. These include general appellations such as siku, but also terms as specialized as qautsaulittuq, ice that breaks after its strength has been tested with a harpoon; kiviniq, a depression in shore ice caused by the weight of the water that passed over and accumulated on its surface during the tide; or iniruvik, ice that cracked because of tide changes and that the cold weather refroze.

http://www.thecanadianencyclopedia.ca/en/article/inuit-words-for-snow-and-ice/

With such complexity of ice conditions, we must recognize that any general understanding of ocean-ice dynamics will not be descriptive of all micro-scale effects on local or regional circumstances.

Short Term Sea Ice Freezing and Melting Cycle

Alarmists only mention positive feedbacks from ice melting, so one is left to wonder why there is any Arctic ice left so many years since the Little Ice Age ended around 1850. Actually there are both positive and negative feedbacks, with one or the other dominating at different times and places.

Of course, the basic cycle is the seasonality of sunless winters and sunlit summers.

Remember that ice grows because of a transfer of heat from the relatively warm ocean to the cold air above. Also remember that ice insulates the ocean from the atmosphere and inhibits this heat transfer. The amount of insulation depends on the thickness of the ice; thicker ice allows less heat transfer. If the ice becomes thick enough that no heat from the ocean can be conducted through the ice, then ice stops growing. This is called the thermodynamic equilibrium thickness. It may take several years of growth and melt for ice to reach the equilibrium thickness. In the Arctic, the thermodynamic equilibrium thickness of sea ice is approximately 3 meters (9 feet). However, dynamics can yield sea ice thicknesses of 10 meters (30 feet) or more. Equilibrium thickness of sea ice is much lower in Antarctica, typically ranging from 1 to 2 meters (3 to 6 feet).

Snow has an even higher albedo than sea ice, and so thick sea ice covered with snow reflects as much as 90 percent of the incoming solar radiation. This serves to insulate the sea ice, maintaining cold temperatures and delaying ice melt in the summer. After the snow does begin to melt, and because shallow melt ponds have an albedo of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15. As a result, melt ponds are associated with higher energy absorption and a more rapid ice melt.

https://nsidc.org/cryosphere/seaice/processes/growth_melt_cycle.html

The short-term dynamics of sea ice freezing and melting can be summarized in this diagram from Dr. Judith Curry:

sea-ice-climate-dynamics_Image_5

Dr. Curry has written extensively on sea ice, and an introduction to her sources is here:

http://judithcurry.com/2014/10/15/new-presentations-on-sea-ice/

Decadal Variability in Sea Ice Extent

Medium term sea ice variations are well described by Lawrence A. Mysak and Silvia A. Venegas of the Centre for Climate and Global Change Research and Department of Atmospheric and Oceanic
Sciences, McGill University, Montreal, Quebec, Canada.

Abstract: A combined complex empirical orthogonal function analysis of 40 years of annual sea ice concentration (SIC) and winter sea level pressure (SLP) data reveals the existence of an approximately 10-year climate cycle in the Arctic and subarctic.

paper_ice_Mysak1998

“Starting at the top of the loop in Figure 4, we propose that large SIC (Sea Ice Concentration) positive anomalies are created in the Greenland Sea by a combination of anomalous northerly winds and a relatively small northward transport of warm air (sensible heat) [Higuchi et al., 1991] associated with a negative NAO pattern. The relationship between severe sea ice conditions in the Greenland Sea and a weak atmospheric circulation (negative NAO) was previously noticed by Power and Mysak [1992]. Over the Barents Sea, on the other hand, the formation of the large positive SIC anomalies may be mainly due to weaker-than-normal advection of warm water by the northward branch of the North Atlantic Current when the NAO index is negative (R. R. Dickson, pets.comm., 1998).”

“These SIC anomalies are then advected into the Labrador Sea by the local mean ocean circulation over a 3-4 year period. When the southern part of the Greenland Sea thus becomes relatively ice free (as implied by the minus sign at the upper-right corner of the loop), strong heating of the atmosphere during winter occurs, which is hypothesized to cause the Icelandic Low to deepen at that time (hence the plus sign on the right-hand side of the loop). This may help change the polarity of the NAO. When the NAO index is positive (deep Icelandic Low), the wind anomalies create positive SIC anomalies in the Beaufort Sea (see bottom of the loop), which are then slowly advected out of the Arctic via the Beaufort Gyre and Transpolar Drift Stream over a 3-4 year period (see lower-left corner and left-hand side of loop).”

“As a consequence, the Greenland Sea becomes extensively ice covered, which suddenly cuts off the heat flux to the atmosphere during winter and hence is likely to cause the Icelandic Low to weaken at that time, which may contribute to changing the NAO polarity. This brings us back to the beginning of the cycle (top of Figure 4) after about 10 years.”

http://lightning.sbs.ohio-state.edu/geo622/paper_ice_Mysak1998.pdf

Multi-Decadal Sea Ice Dynamics

In a 2005 publication Mysak presents additional empirical evidence for these ocean-ice mechanisms:

“In this paper we have shown that an intermediate complexity climate model consisting of a 3-D ocean component, a state-of-the-art sea-ice model (with elastic-viscous-plastic rheology) and an atmospheric energy-moisture balance model can successfully simulate a large number of observed changes in the Arctic Ocean and sea-ice cover during the past half-century.”

“Morison et al. (1998) found an increase in both the temperature and salinity at depths of 200–300 m in the eastern Arctic. . .This increase in salinity is also supported by the work of Steele and Boyd (1998) who found that the winter mixed layer in the Eurasian Basin had higher salinity values in the early 1990s compared with the 40-year record of the Environmental Working Group (EWG) Joint US-Russian Arctic Atlas. Morison et al. (1998) argue that the increase in salinity represents a westward advance into the Arctic of the front between the waters of the eastern and western Arctic. The aforementioned temperature and salinity changes support the hypothesis that the warm and salty Atlantic water penetrated further into the central Arctic Basin during the 1990s, and thus has pushed the front between Atlantic derived and Pacific derived waters westward.”

http://www.esmg.mcgill.ca/jan_paper/Mysak_et_al_2005.pdf

Summary: Sea Ice Impacts Climate Strongly, this century and beyond.

“Sea ice is a key player in the climate system, affecting local, and to some degree remote regions, via its albedo effect. Sea ice also strongly reduces air-sea heat and moisture fluxes (Ruddiman and McIntyre 1981; Gildor and Tziperman 2000), and thus may cause the air overlying it to be cooler and drier compare to air overlying ice-free ocean (Chiang and Bitz 2005). A significant part (*33 %) of the precipitation over the northern hemisphere (NH) ice sheets is believed to have originated locally from the Norwegian, Greenland and the Arctic seas (Charles et al. 1994;Colleoni et al. 2011). Lastly, sea ice affects the location of the storm track and therefore indirectly also the patterns of precipitation (e.g. Laine et al. 2009; Li and Battisti 2008).”

“Its effect on the hydrological cycle makes sea ice a potentially significant player in the temperature-precipitation feedback (Le-Treut and Ghil 1983), according to which increase in temperature intensifies the hydrological cycle and thus the snow accumulation over ice sheets. This feedback is an important part of the sea-ice switch mechanism for glacial cycles, for example Gildor and Tziperman (2000). Indeed, proxy records show drastic increase in accumulation rate during interstadial periods (Cuffey and Clow 1997; Alley et al. 1993; Lorius et al. 1979), when the sea-ice retreats from its maximal extent.”

The largest ice cap in the Eurasian Arctic – Austfonna in Svalbard – is 150 miles long with a thousand waterfalls in the summer

“We find that in a cold, glacial climate snowfall rate over the ice sheets is reduced as a result of increasing sea-ice extent (compare LGM and PDSI experiments). An increased sea-ice extent cools the climate even more, the precipitation belt is pushed southward and the hydrological cycle weakens.

We find that the albedo feedback of an extended sea-ice cover in an LGM-like climate only weakly affects the reduction of snowfall rate.

indicating that the insulating feedback is responsible for a large part of the suppression of precipitation by sea ice. It follows that the hydrological cycle is more sensitive to the insulating effect of sea ice than to its albedo. There are two reasons to the larger contribution of the insulating effect to the temperature-precipitation feedback. First, the overall cooling of the insulating effect is about twice than that of the albedo. This by itself is expected to lead to a more significant change in precipitation. In addition, the insulation effect not only reduce air-sea heat flux, it also directly prevents evaporation from ice-covered regions, which are a major source of precipitation over the NH ice sheets (Charles et al. 1994).

http://www.environment.harvard.edu/docs/faculty_pubs/tziperman_sea.pdf

Conclusion: It’s the Ice and the Water

Regardless of the uncertainties in the underlying principal mechanisms of the sea ice-AMO-AMOC linkages, it is clear that multidecadal sea-ice variability is directly or indirectly related to natural fluctuations in the North Atlantic. This study provides strong, long-term evidence to support modeling results that have suggested linkages between Arctic sea ice and Atlantic multidecadal variability [Holland et al., 2001; Jungclaus et al., 2005; Mahajan et al., 2011].

Here we present observational evidence for pervasive and persistent multidecadal sea ice variability, based on time-frequency analysis of a comprehensive set of several long historical and paleoproxy sea ice records from multiple regions. Moreover, through explicit comparisons with instrumental and proxy records, we demonstrate covariability with the Atlantic Multidecadal Oscillation (AMO).

http://www.seas.harvard.edu/climate/eli/reprints/Gildor-Ashkenazy-Tziperman-Lev-2014.pdf

Update May 30,2015 From E.M. Smith and Salvatore Del Prete

I think I can take a crack as answering some of the questions and pointing at a likely structure for some of the other bits.

Why is it whenever the climate changes the climate does not stray indefinitely from it’s mean in either a positive or negative direction? Why or rather what ALWAYS brings the climate back toward it’s mean value ? Why does the climate never go in the same direction once it heads in that direction?

IMHO the answer is that there is a hysteresis from water that limits the excursions. On one end, freezing tends to cut down heat dumping as frozen ice does not radiate as much heat to space. On the other end, tropical storm formation limits heat in the equatorial oceans as you get more water evaporation / rise / precipitation cycles and more radiation to space from the tropopause / stratosphere. So we don’t get ‘brought back to the mean’, but rather switch from an ice ball (most of the time) to a warm & wet (10% of the time). This switching is the Malankovitch cycle, and it is driven by changes in the orbital roundness, precession of the equinox, and changes of tilt of the planet (that are not really changes of tilt, they are changes in position relative to the celestial equator.

Much more here:

https://chiefio.wordpress.com/2015/05/29/salvatore-del-prete-thesis/

 

An Alternate Climate Encyclical

With the Vatican preparing to declare UN IPCC science as Christian Truth, I am reminded of Aristotle (384 to 322 BC) who said:

“Give me a child until he is 7 and I will show you the man.”

If Aristotle knew what we know today about how oceans make the climate, how might he convey that meaning to one of his young Greek students?

Perhaps he would tell the story this way.

Poseidon, Lord of the Oceans

I am Poseidon and I rule the oceans, and with them I make the climate what it is.

I store the sun’s energy in my ocean water so that our world is neither too hot nor too cold.

I add water and energy into the air and together we spread warmth from the tropics to the poles. There are many obstacles and delays along the way, and there are clashes between hot and cold, which you know as storms.

The land masses make basins to collect water and energy and I send heat to each basin to form its own climate. Water heat is transported slowly, between basins and from equator to pole and back again.

The water in the air returns as rain falling on land and sea. Near the poles the water freezes and stays, sometimes for many years, until rejoining the ocean. Always the water returns and the cycles continue.

Do not be afraid of the future. Respect the oceans, take care of the land and each other, and all will be well.

The Climate According to Poseidon

Dynamic Duo: The Ocean-Air Partnership

Update May 19, 2015 text added at end.

Earlier I wrote an essay about our living on a water world. Then an essay described the role of oceans as a climate flywheel, storing massive amounts of solar energy and thereby stabilizing fluctuations in temperature and climate. A recent post about oceans making global temperature changes drew some comments about downplaying the role of the atmosphere in climate change. So I want to clarify some things.

The Dynamic Duo

Climate change is a coupled ocean-air dynamic, stimulated by ocean heat transfers into the air, and involving the two fluids (air and water) feeding off each other.

To maintain an approximate steady state climate the ocean and atmosphere must move excess heat from the tropics to the heat deficit polar regions. Additionally the ocean and atmosphere must move freshwater to balance regions with excess dryness with those of excess rainfall. The movement of freshwater in its vapor, liquid and solid state is referred to as the hydrological cycle.

In low latitudes the ocean moves more heat poleward than does the atmosphere, but at higher latitudes the atmosphere becomes the big carrier. The wind driven ocean circulation moves heat mainly on the horizontal plane. For example, in the North Atlantic, warm surface water move northward within the Gulf Stream on the western side of the ocean, to be balanced by cold surface water moving southward within the Canary Current on the eastern side of the ocean.  The thermohaline circulation moves heat mainly in the vertical plane. For example, North Atlantic Deep Water with a temperature of about 2°C flows towards the south in the depth range 2000 to 4000 meters to be balanced by warmer water (greater than 4°C) flowing northward within the upper 1000 meters.

The ocean role in climate would be zero if there were an impervious lid over the ocean, but there is not, across the sea surface pass heat, water, momentum, gases and other materials. The wind exerts a stress on the sea surface that induces the Ekman transport and wind driven circulation.

http://eesc.columbia.edu/courses/ees/climate/lectures/o_atm.html

A lot of factors affect heat transfers from oceans to atmosphere, but the main ones are advection (heat in water flowing horizontally), mixing (vertical upwelling and downwelling of warmer and colder waters) and surface evaporation (latent heat rising with water vapor converted from liquid). The latter is greatly affected by wind which adds to the complexity of the process. For this essay, I will leave on the side the issue of sea ice dynamics, including the latent heat released in its freezing.

Ocean-atmosphere Interactions

The ocean can warm or cool the air in a number of different ways. For example, when the air is at a lower temperature than seawater, the ocean transfers heat to the lower atmosphere, which becomes less dense as the heat causes molecules in the air to move farther apart. As a result, a low-pressure air mass forms over that part of the ocean. (Conversely, cool or cold waters lead to the formation of high-pressure air masses as air molecules move closer together.) Because air always flows from areas of higher pressure to those of lower pressure, winds are diverted toward the low-pressure area.

Among winds that are affected by such pressure changes are the jet streams, bands of fast-moving, high-altitude air currents. Jet streams supply energy to developing storms at lower altitudes and then influence their movement. In this way, the ocean alters the direction of storm tracks. Some storms even reverse direction as the result of ocean-influenced air-pressure changes.

The ocean’s currents make it possible for these weather effects to be widely distributed. Some currents carry warm water from tropical and subtropical regions toward the poles, while other currents move cool water in the opposite direction. The Gulf Stream is a current that transports warm water across the North Atlantic Ocean from Florida toward Europe. Before reaching Europe, the Gulf Stream breaks up into several other currents, one of which flows to the British Isles and Norway. The heat carried in this current warms the winds that blow over these regions, helping to keep winters there from becoming bitterly cold.

In this way, the ocean’s circulation compensates somewhat for the sun’s unequal heating of the Earth, in which the tropics receive more energy from the sun than the poles. Were it not for the moderating effects of ocean currents on air temperatures, the tropics would be much hotter than they are and the polar regions even colder.

Besides transferring heat to the atmosphere, the ocean also adds water to the air through evaporation. When the sun’s heat causes surface water to evaporate, warm water vapor rises into the atmosphere. As the water vapor rises higher, it cools into tiny water droplets and ice crystals, which collect together to form large clouds. The clouds soon return their moisture to the surface as rain, snow, sleet, or hail. Most evaporation occurs in the warm waters of the tropics and subtropics, providing moisture for tropical storms.

Virtually all rain comes from the evaporation of seawater. Though this may seem surprising, it makes sense when one considers that about 97 percent of all water on Earth is in the ocean. The Earth’s water cycle, or hydrologic cycle, consists largely of the never-ending circulation of water from the ocean to the atmosphere and then back to the ocean.

http://science.howstuffworks.com/how-the-ocean-affects-climate-info1.htm

Oceanic Oscillations

Most widely known is the El Nino Southern Oscillation, or ENSO. Many other naturally occurring ocean-atmosphere oscillations in the Pacific, Atlantic, and Indian Oceans have been recognized and named. Some of them have much more of an impact on climate and weather patterns in the U.S. and elsewhere than ENSO. As during ENSO, in many of these ocean and atmosphere interact as a coupled system, with ocean conditions influencing the atmosphere and atmospheric conditions influencing the ocean. However, not all exert as strong an influence on global weather patterns, and some are even less regular than ENSO.

Many oscillations are under study:

Antarctic Oscillation (AAO), also referred to as the Southern Annular Mode (SAM).

Arctic Oscillation (AO)

The AO and the North Atlantic Oscillation (see below) are collectively referred to as the Northern Annular Mode (NAM).

Atlantic Multidecadal Oscillation (AMO)

Indian Ocean Dipole (IOD)

Madden-Julian Oscillation (MJO)

North Atlantic Oscillation (NAO)

North Pacific Gyre Oscillation (NPGO)

North Pacific Oscillation (NPO)

Pacific Decadal Oscillation (PDO)

Pacific-North American (PNA) Pattern

http://www.whoi.edu/main/topic/el-nino-other-oscillations

Each of these patterns has its distinctive qualities, ranging from phases lasting a month or so to multi-decadal phases. Some fundamental features can be seen in all of them:

3 factors

The diagram shows the vertical structure of the ocean surface boundary layer (OSBL) and the processes that deepen. The three sources of turbulence are: wind, buoyancy and waves.

The bulk of the OSBL can be termed the mixed layer, where the temperature and salinity are approximately uniform with depth, and which is often capped below, at the mixed layer depth, by a sharp pycnocline, which extends deeper into the ocean. Three sources of turbulence, namely wind, buoyancy and waves, drive turbulence in this mixed layer, which then deepens the OSBL. Hence a quantitative understanding of these turbulent processes in the OSBL is likely to be the key to understanding the shallow biases in mixed layer depth.

Deepening of the OSBL implies an increase in potential energy, and hence requires an energy source, such as turbulent kinetic energy (TKE).

Belcher, S. E., et al. (2012), A global perspective on Langmuir turbulence in the ocean surface boundary
layer, Geophys. Res. Lett., 39, L18605, doi:10.1029/2012GL052932.
http://onlinelibrary.wiley.com/doi/10.1029/2012GL052932/full

The Madden-Julian Oscillation is one of the simpler oscillations to understand, partly because of its short 30-60 day cycle.

Even so, you can see there is a lot going on, and a lot of variables affecting both strength and timing. But the same dynamic plays out in all the oscillations, including ENSO.

ENSO Cycle 4

First, the atmosphere responds to the ocean: the atmospheric fluctuations manifested as the Southern Oscillation are mostly an atmospheric response to the changed lower boundary conditions associated with El Nino SST fluctuations.

Second, the ocean responds to the atmosphere: the oceanic fluctuations manifested as El Nino seem to be an oceanic response to the changed wind stress distribution associated with the Southern Oscillation.

Third, the El Nino-Southern Oscillation phenomenon arises spontaneously as an oscillation of the coupled ocean-atmosphere system.

Once the El Nino event is fully developed, negative feedbacks begin to dominate the Bjerknes positive feedback, lowering the SST and bringing the event to its end after several months.

Schematic of the feedback inherent in the Pacific Ocean-atmosphere interaction. This has become known as the Bjerknes feedback.

When ocean and atmospheric conditions in one part of the world change as a result of ENSO or any other oscillation, the effects are often felt around the world. The rearrangement of atmospheric pressure, which governs wind patterns, and sea-surface temperature, which affects both atmospheric pressure and precipitation patterns, can drastically rearrange regional weather patterns, occasionally with devastating results.

Because it affects ocean circulation and weather, an El Niño or La Niña event can potentially lead to economic hardships and disaster. The potential is made worse when these combine with another, often overlooked environmental problem. For example, overfishing combined with the cessation of upwelling during an El Niño event in 1972 led to the collapse of the Peruvian anchovy fishery.

Extreme climate events are often associated with positive and negative ENSO events. Severe storms and flooding have been known to ravage areas of South America and Africa, while intense droughts and fires have occurred in Australia and Indonesia during El Niño events.

http://faculty.washington.edu/kessler/occasionally-asked-questions.html

Summary

The picture that emerges from this analysis is that the wind-driven meridional overturning circulation in the upper Pacific Ocean has been slowing down since the 1970s. This slowdown can account for the recent anomalous surface warming in the tropical Pacific, as the supply of cold pycnocline water originating at higher latitudes to feed equatorial upwelling has decreased. The Southern Hemisphere is responsible for about half of the observed decrease in equatorward pycnocline transport. Thus, perspectives on decadal variability limited to the Northern Hemisphere alone are incomplete. The fact that few studies have considered a role for the Southern Hemisphere ocean is presumably a consequence of limited data availability rather than a lack of decadal signal in the southern tropics and Subtropics.

The oceanic and atmospheric processes that we have described work together so as to reinforce each other, similar to the positive feedbacks that occur during ENSO events. For example, weaker easterly trade winds in the equatorial Pacific would result in reduced Ekman and geostrophic meridional transports, reduced equatorial upwelling, and warmer equatorial sea surface temperatures. Warmer surface temperatures in turn would alter patterns of deep atmospheric convection so as to favour weaker trade winds. If the system is to oscillate on decadal timescales, then delayed negative feedback mechanisms, one candidate for which involves planetary scale ocean waves, must also be important.

Similarities in the spatial structures of the PDO and ENSO (both, for example, have phases that are characterized by warm tropics and a cool central North Pacific, and vice versa) have raised questions about the possible interaction between interannual- and decadal timescale phenomena in the Pacific. In particular, since 1976±77 there have been fewer La Nina events, and more frequent, stronger, and longer-lasting El Nino events.

Whether this recent change in the character of the ENSO cycle is a consequence or a cause of underlying decadal-timescale variability is unknown. It could be that the decadal changes in circulation described here operate independently from those that affect the ENSO cycle. If so, they would modify the background state on which ENSO develops, and thereby precondition interannual fluctuations to preferred modes of
behaviour. Alternatively, the observed decadal changes may simply be the low-frequency residual of random or chaotic fluctuations in tropical ocean±atmosphere interactions that give rise to the ENSO cycle itself. In either case, a complete understanding of climate variability spanning interannual to decadal timescales in the Pacific basin will need to account for the slowly varying meridional overturning circulation between the tropics and subtropics.

http://ic.ucsc.edu/~ammoore/ocea290e/mcphaden+zhang_nature_2002.pdf

Conclusion

Ocean oscillations are profoundly uncertain, not only because each one is erratic in the timing and strength of phase changes, but also because they have interactive effects upon each other. And with time cycles differing from 1-2 months to 30-60 years the complexity of movements is enormous.

Even today, after many years of study by highly intelligent people, the factors are murky enough that coupled ocean-atmospheric models still lack skill to forecast the patterns. And so, in 2015, we find advocates for reducing use of fossil fuels hoping and praying for a warm water blob in the Northern Pacific to intensify or endure so that the average global temperature will trend higher than last year.

Of course, the satellite records have 1998 as the warmest year by a wide margin. And why was that year so warm? It was a super El Nino. This is Oceans making climate, no mistake about it.

Update May 19, 2015

Dr. William Gray adds the longer term context to these oscillations in his 2012 paper:

“The global surface warming of about 0.7°C that has been experienced over the last 150 years and the multi-decadal up-and-down global temperature changes of 0.3-0.4°C that have been observed over this period are hypothesized to be driven by a combination of multi-century and multi-decadal ocean circulation changes. These ocean changes are due to naturally occurring upper ocean salinity variations. Changes in CO2 play little role in these salinity driven ocean climate forcings. “

Many ocean-climate dynamics are explained in Dr. Gray’s paper:

http://tropical.atmos.colostate.edu/Includes/Documents/Publications/gray2012.pdf

Included are excellent diagrams and charts, such as these:

gray2012MOC

gray2012multi-decadal

The Dynamic Duo: Ocean and Air

Oceans make climate is by partnering with the atmosphere. It’s a match made in heaven: Ocean is dense, powerful, slow and constrained; Atmosphere is thin, light, fast and free. Ocean has solar heat locked in its Abyss, Atmosphere is open to the cold of space. Together they take on the mission of spreading energy far and wide from the equator to the poles, and into space, the final frontier.

Here’s how it goes. Working together as companion fluids, and feeding off each other, they make winds, waves, weather and climate.

But make no mistake: Ocean is Batman, Atmosphere is Robin; Ocean is Captain Kirk, Atmosphere is Spock; Ocean the dog, Atmosphere the tail.

As for the villainous CO2, that does not rise to the level of Joker or Penguin; CO2 is probably best cast as the Riddler:

Empirical Evidence: Oceans Make Climate

Updated May 11,18 and 19 with text added at the end.

Further update on May 27 at the end.

You only have to compare Sea Surface Temperatures (SST) from HADSST3 with estimates of Global Mean Surface Temperatures (GMST) from Hadcrut4 and RSS.


This first graph shows how global SST has varied since 1850. There are obvious changepoints where the warming or cooling periods have occurred.

This graph shows in green Hadcrut4 estimates of global surface temperature, including ocean SST, and near surface air temperatures over land. The blue line from RSS tracks lower tropospheric air temperatures measured by satellites, not near the surface but many meters higher. Finally, the red line is again Hadsst3 global SST All lines use 30-month averages to reduce annual noise and display longer term patterns.

Strikingly, SST and GMST are almost synonymous from the beginning until about 1980. Then GMST diverges with more warming than global SST. Satellite TLT shows the same patterns but with less warming than the surface. Curious as to the post 1980s patterns, I looked into HADSST3 and found NH SST warmed much more strongly during that period.

This graph shows how warming from circulations in the Northern Pacific and Northern Atlantic drove GMST since 1980. And it suggests that since 2005 NH SST is no longer increasing, and may turn toward cooling.

Surface Heat Flux from Ocean to Air

Now one can read convoluted explanations about how rising CO2 in the atmosphere can cause land surface heating which is then transported over the ocean and causes higher SST. But the interface between ocean and air is well described and measured. Not surprisingly it is the warmer ocean water sending heat into the atmosphere, and not the other way around.

The graph displays measures of heat flux in the sub-tropics during a 21-day period in November. Shortwave solar energy shown above in green labeled radiative is stored in the upper 200 meters of the ocean. The upper panel shows the rise in SST (Sea Surface Temperature) due to net incoming energy. The yellow shows latent heat cooling the ocean, (lowering SST) and transferring heat upward, driving convection.

From
An Investigation of Turbulent Heat Exchange in the Subtropics
James B. Edson

“One can think of the ocean as a capacitor for the MJO (Madden-Julian Oscillation), where the energy is being accumulated when there is a net heat flux into the ocean (here occurring to approximately November 24) after which it is released to the atmosphere during the active phase of the MJO under high winds and large latent heat exchange.”
http://www.onr.navy.mil/reports/FY13/mmedson.pdf

Conclusion

As we see in the graphs ocean circulations change sea surface temperatures which then cause global land and sea temperatures to change. Thus, oceans make climate by making temperature changes.

On another post I describe how oceans also drive precipitation, the other main determinant of climate. Oceans make rain, and the processes for distributing rain over land are shown here: https://rclutz.wordpress.com/2015/04/30/here-comes-the-rain-again/

And a word from Dr. William Gray:

“Changes in the ocean’s deep circulation currents appears to be, by far, the best physical explanation for the observed global surface temperature changes (see Gray 2009, 2011, 2012, 2012). It seems ridiculous to me for both the AGW advocates and us skeptics to so closely monitor current weather and short-time climate change as indication of CO2’s influence on our climate. This assumes that the much more dominant natural climate changes that have always occurred are no longer in operation or have relevance.”

http://www.icecap.us/

Indeed, Oceans Make Climate, or as Dr. Arnd Bernaerts put it:
“Climate is the continuation of oceans by other means.”

Update 1 May 11, 2015

Kenneth Richards provided some supporting references in a comment at Paul Homewood’s site. They are certainly on point especially this one:
“Examining data sets of surface heat flux during the last few decades for the same region, we find that the SST warming was not a consequence of atmospheric heat flux forcing. Conversely, we suggest that long-term SST warming drives changes in atmosphere parameters at the sea surface, most notably an increase in latent heat flux, and that an acceleration of the hydrological cycle induces a strengthening of the trade winds and an acceleration of the Hadley circulation.”

That quote is from Servain et al, unfortunately behind a paywall.  The paper is discussed here:

http://hockeyschtick.blogspot.ca/2014/09/new-paper-finds-climate-of-tropical.html

Full comment from Richards:

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00651.1
The surface of the world’s oceans has been warming since the beginning of industrialization. In addition to this, multidecadal sea surface temperature (SST) variations of internal [natural] origin exist. Evidence suggests that the North Atlantic Ocean exhibits the strongest multidecadal SST variations and that these variations are connected to the overturning circulation. This work investigates the extent to which these internal multidecadal variations have contributed to enhancing or diminishing the trend induced by the external radiative forcing, globally and in the North Atlantic. A model study is carried out wherein the analyses of a long control simulation with constant radiative forcing at preindustrial level and of an ensemble of simulations with historical forcing from 1850 until 2005 are combined. First, it is noted that global SST trends calculated from the different historical simulations are similar, while there is a large disagreement between the North Atlantic SST trends. Then the control simulation is analyzed, where a relationship between SST anomalies and anomalies in the Atlantic meridional overturning circulation (AMOC) for multidecadal and longer time scales is identified. This relationship enables the extraction of the AMOC-related SST variability from each individual member of the ensemble of historical simulations and then the calculation of the SST trends with the AMOC-related variability excluded. For the global SST trends this causes only a little difference while SST trends with AMOC-related variability excluded for the North Atlantic show closer agreement than with the AMOC-related variability included. From this it is concluded that AMOC [Atlantic meridional overturning circulation] variability has contributed significantly to North Atlantic SST trends since the mid nineteenth century.
—–
http://link.springer.com/article/10.1007%2Fs00382-014-2168-7
After a decrease of SST by about 1 °C during 1964–1975, most apparent in the northern tropical region, the entire tropical basin warmed up. That warming was the most substantial (>1 °C) in the eastern tropical ocean and in the longitudinal band of the intertropical convergence zone. Examining data sets of surface heat flux during the last few decades for the same region, we find that the SST [sea surface temperature] warming was not a consequence of atmospheric heat flux forcing [greenhouse gases]. Conversely, we suggest that long-term SST warming drives changes in atmosphere parameters at the sea surface, most notably an increase in latent heat flux, and that an acceleration of the hydrological cycle induces a strengthening of the trade winds and an acceleration of the Hadley circulation. These trends are also accompanied by rising sea levels and upper ocean heat content over similar multi-decadal time scales in the tropical Atlantic. Though more work is needed to fully understand these long term trends, especially what happens from the mid-1970’s, it is likely that changes in ocean circulation involving some combination of the Atlantic meridional overtuning circulation [AMOC] and the subtropical cells are required to explain the observations.
—–
http://www.nature.com/ncomms/2014/141208/ncomms6752/full/ncomms6752.html
The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the global climate system, responsible for a large fraction of the 1.3 PW northward heat transport in the Atlantic basin. Numerical modelling experiments suggest that without a vigorous AMOC, surface air temperature in the North Atlantic region would cool by around 1–3 °C, with enhanced local cooling of up to 8 °C in regions with large sea-ice changes. Substantial weakening of the AMOC would also cause a southward shift of the inter-tropical convergence zone, encouraging Sahelian drought, and dynamic changes in sea level of up to 80 cm along the coasts of North America and Europe.

Update 2 May 18, 2015

This graph from Mike at climategrog shows more empirical evidence for ocean climate making, this time the relation to CO2 concentrations. The chart shows a high correlation between rates of change, not comparing directly the temperature or CO2 values or anomalies. Thus, a positive datapoint in the graph means an increase in the rate of change, negative being the rate changing downward.

The correlation is clear. There is no credible case for claiming that changes in CO2 cause changes in SST. Plenty of evidence that SST is the cause and CO2 the effect.

Update 3 May 19, 2015

On the ocean-air heat flux

Summary from
http://eesc.columbia.edu/courses/ees/climate/lectures/o_atm.html

Much of the direct and diffuse solar short wave (less than 2 micros, mostly in the visible range) electromagnetic radiation that reaches the sea surface penetrates the ocean heating the sea water down to about 100 to 200 meters. Solar heating of the ocean on a global average is 168 watts per square meter

The infrared radiation emitted from the ocean is quickly absorbed and re-emitted by water vapor and carbon dioxide and other greenhouse gases residing in the lower atmosphere. Much of the radiation from the atmospheric gases, also in the infrared range, is transmitted back to the ocean, reducing the net long wave radiation heat loss of the ocean. Net back radiation cools the ocean, on a global average by 66 watts per square meter.

When air is contact with the ocean is at a different temperature than that the sea surface, heat transfer by conduction takes place. On average the ocean is about 1 or 2 degrees warmer than the atmosphere so on average ocean heat is transferred from ocean to atmosphere by conduction.

If the ocean were colder than the atmosphere (which of course happens) the air in contact with the ocean cools, becoming denser and hence more stable, more stratified. As such the conduction process does a poor job of carrying the atmosphere heat into the cool ocean. On global average the oceanic heat loss by conduction is only 24 watts per square meter.

The largest heat loss for the ocean is due to evaporation, which links heat exchange with hydrological cycle (Fig. 4). On global average the heat loss by evaporation is 78 watts per square meter.

Update 4 May 19, 2015

Dr. William Gray in his 2012 paper:

“The global surface warming of about 0.7°C that has been experienced over the last 150 years and the multi-decadal up-and-down global temperature changes of 0.3-0.4°C that have been observed over this period are hypothesized to be driven by a combination of multi-century and multi-decadal ocean circulation changes. These ocean changes are due to naturally occurring upper ocean salinity variations. Changes in CO2 play little role in these salinity driven ocean climate forcings. “

http://tropical.atmos.colostate.edu/Includes/Documents/Publications/gray2012.pdf

Update 5 May 27, 2015

The RAPID moorings being deployed. Credit: National Oceanography Centre

A new study, by scientists from the University of Southampton and National Oceanography Centre (NOC), implies that the global climate is on the verge of broad-scale change that could last for a number of decades. This new climatic phase could be half a degree cooler.

The change to the new set of climatic conditions is associated with a cooling of the Atlantic, and is likely to bring drier summers in Britain and Ireland, accelerated sea-level rise along the northeast coast of the United States, and drought in the developing countries of the Sahel region. Since this new climatic phase could be half a degree cooler, it may well offer a brief reprise from the rise of global temperatures, as well as resulting in fewer hurricanes hitting the United States.

The study, published in Nature, proves that ocean circulation is the link between weather and decadal scale climatic change. It is based on observational evidence of the link between ocean circulation and the decadal variability of sea surface temperatures in the Atlantic Ocean.

Lead author Dr Gerard McCarthy, from the NOC, said: “Sea-surface temperatures in the Atlantic vary between warm and cold over time-scales of many decades. These variations have been shown to influence temperature, rainfall, drought and even the frequency of hurricanes in many regions of the world. This decadal variability, called the Atlantic Multi-decadal Oscillation (AMO), is a notable feature of the Atlantic Ocean and the climate of the regions it influences.”

The strength of ocean currents has been measured by a network of sensors, called the RAPID array, which have been collecting data on the flow rate of the Atlantic meridonal overturning circulation (AMOC) for a decade.

Dr David Smeed, from the NOC and lead scientist of the RAPID project, adds: “The observations of AMOC from the RAPID array, over the past ten years, show that it is declining. As a result, we expect the AMO is moving to a negative phase, which will result in cooler surface waters. This is consistent with observations of temperature in the North Atlantic.”

http://www.sciencedaily.com/releases/2015/05/150527133932.htm

And an observation from Dr. Robert E. Stevenson:

“The atmosphere cannot warm until the underlying surface warms first. The lower atmosphere is transparent to direct solar radiation, preventing it from being significantly warmed by sunlight alone. The surface atmosphere thus gets its warmth in three ways: from direct contact with the oceans; from infrared radiation off the ocean surface; and, from the removal of latent heat from the ocean by evaporation. Consequently, the temperature of the lower atmosphere is largely determined by the temperature of the ocean.”

http://www.21stcenturysciencetech.com/articles/ocean.html