Revisiting Bratcher and Giese (2002)
Guest Post by Bob Tisdale
INTRODUCTION
In a comment in the March 2009 SST Anomaly Update thread, Blogger DB reminded me of the Bratcher and Giese (2002) paper “Tropical Pacific Decadal Variability and Global Warming” [GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO. 19, 1918, doi:10.1029/2002GL015191, 2002].
Abstract:
“An analysis of ocean surface temperature records show that low frequency changes of tropical Pacific temperature lead global surface air temperature changes by about 4 years. Anomalies of tropical Pacific surface temperature are in turn preceded by subsurface temperature anomalies in the southern tropical Pacific by approximately 7 years. The results suggest that much of the decade to decade variations in global air temperature may be attributed to tropical Pacific decadal variability. The results also suggest that subsurface temperature anomalies in the southern tropical Pacific can be used as a predictor for decadal variations of global surface air temperature. Since the southern tropical Pacific temperature shows a distinct cooling over the last 8 years, the possibility exists that the warming trend in global surface air temperature observed since the late 1970’s may soon weaken.”
Link to GRL Abstract:
http://www.agu.org/pubs/crossref/2002/2002GL015191.shtml
Also refer to the copy of the Bratcher and Giese slide presentation:http://www.decvar.org/documents/CCR_workshop/bratcher.htm?PHPSESSID=df81bed52419c895efe9135099fb26e9
And theWorldClimateReport post on the study here:http://www.worldclimatereport.com/archive/previous_issues/vol8/v8n04/feature1.htm
And CO2Science did a write up here:http://www.co2science.org/articles/V6/N20/C1.php
As illustrated in Figure 1 (Figure 1 of Bratcher and Giese 2002), their comparison of Global Temperature Anomaly (GISTEMP) and NINO3 SST Anomaly (Simple Ocean Data Assimilation-SODA) ran from 1948 to 2000. The graph appears to be of annual (not monthly) data, with 5-year smoothing as discussed in the paper. The two questions that struck me were: How far back in time do the two datasets coincide and what would the updated graph look like? (The latter question was also part of DB’s comments.)
http://i40.tinypic.com/nyd7nn.jpg
Figure 1
The problem: the easily available SODA data through the KNMI Climate Explorer website only includes the years of 1958 to 2004. So I’ve substituted ERSST.v3b data in place of the SODA data. I’ve also used monthly instead of annual data.
UPDATING THE GLOBAL TEMPERATURE AND NINO3 SST ANOMALY COMPARISON
Figure 2 illustrates a reasonable facsimile of Cell A of the Bratcher and Giese comparison of Global Surface Temperature and NINO3 SST anomalies. It has been extended in time through February 2009. The global surface temperature data is GISTEMP and the NINO3 SST anomaly data is ERSST.v3b. Bratcher and Giese appear to use different base years than the ones used here (1971-2000), and, of course, the variability appears greater with the monthly data.
http://i44.tinypic.com/abjy9z.jpg
Figure 2
Figure 3 updates Cell B of the Bratcher and Giese Figure 1. Without accounting for volcanic aerosols, any attempt to determine the 4-year lag between NINO3 and Global Surface Temperatures as claimed by Bratcher and Giese would be difficult with these time-series graphs, including Figure 1. However, Global Temperatures do appear to respond gradually over time to the shift in NINO3 SST anomaly. Note the impact of the Pacific Climate Shift of 1976 on the smoothed NINO3 SST anomalies. It stands out in Figures 1, 2, and 3.
http://i44.tinypic.com/14uko7n.jpg
Figure 3
Based on the averages of the smoothed NINO3 SST anomalies for the periods of 1950 through 1975 and of 1978 to present, Figure 4, the magnitude of the 1976 shift in NINO3 SST anomalies is more than 0.4 Deg C. If one considers NINO3 SST anomalies as a forcing, then the rise of global temperatures from 1976 to the early 2000s would then appear to be a natural response to a natural variation.
http://i41.tinypic.com/9st6yw.jpg
Figure 4
EXTENDING THE COMPARISON BACK IN TIME
Figure 5 illustrates the NINO3 SST and global surface temperature anomalies from 1880 to present. Both datasets are smoothed with 61-month (5-year), running-average filters. Two things to consider when looking at the data before 1948: the discontinuity in the SST anomalies at 1945 would have impacted both datasets, and prior to 1914 and the opening of the Panama Canal, there were very few SST samples in the NINO regions. With those in mind, the fact the two datasets do seem to “track” is quite remarkable.
http://i40.tinypic.com/333d9pg.jpg
Figure 5
The NINO3 data was still noisy with the 61-month smoothing, so I changed to a 121-month filter in Figure 6. This seems to aid in illustrating the influence of NINO3 SST anomalies on global surface temperature. ENSO appears to dictate whether global surface temperatures rise or fall over decadal periods. It also illustrates a gradual “ramp up” required to overcome global thermal inertia.
http://i39.tinypic.com/1492ohi.jpg
Figure 6
There’s a mismatch with those two datasets. The NINO3 SST anomalies are based on ERSST.v3b data, while GISS uses HADSST data prior to November 1981 for their global surface temperature product. So let’s look at matching data.
NINO3 AND GLOBAL SST ANOMALIES USING ERSST.v3b DATA
In Figure 7, the GISS Global Surface Temperature data has been replaced by ERSST.v3b Global SST Anomaly data. The most significant difference between the GISTEMP Global Surface Temperature and the ERSST.v3b SST data can be found between ~1880 and 1900. Note how the drop in the temperature from 1880 to 1900 is exaggerated in the ERSST.v3b Global SST anomaly data.
Note also how the effect of NINO3 SST anomalies on Global SST anomalies is still clear after 1914. This is especially true following the shift in NINO3 SST anomalies in 1976.
http://i43.tinypic.com/34e6ow7.jpg
Figure 7
THE SECOND CONCLUSION OF BRATCHER AND GIESE 2002
As noted earlier, Bratcher and Giese wrote in the Abstract, “Anomalies of tropical Pacific surface temperature are in turn preceded by subsurface temperature anomalies in the southern tropical Pacific by approximately 7 years.” They illustrated this lag in their Figure 3, my Figure 8.
http://i39.tinypic.com/w970ao.jpg
Figure 8
In the body of the paper, Bratcher and Giese discuss and illustrate the lag between the subsurface Tropical Pacific temperature and NINO3 SST anomalies. I am not trying to undermine that in any way. But the second problem I encountered while trying to update the Bratcher and Giese 2002 paper was the availability of Subsurface Temperature data for the Tropical Pacific Ocean. Simple Ocean Data Assimilation (SODA) data through KNMI does not include the subsurface temperature data.
It was my original intent to end the comparisons here, which is why the graphs are titled “Revisiting Part of Bratcher & Giese 2002”, but then it struck me that this would be a good time to illustrate a possible influence of the Southern Ocean on ENSO.
COMPARING SST ANOMALIES FOR THE SOUTHEAST PACIFIC ACC AND NINO3
Figure 9 shows the locations of NINO3 region and the portion of the Antarctic Circumpolar Current (ACC) in the extreme Southeast Pacific used in the following comparison. Note how the Humboldt Current carries waters from the ACC along the coasts of Chile and Peru and up to the eastern equatorial Pacific. The SST anomalies of the Southeast Pacific ACC should have an influence on NINO3 SST anomalies.
http://i39.tinypic.com/ziqgkj.jpg
Figure 9
Figure 10 is a comparison of NINO3 and Southeast Pacific ACC SST anomalies. Again, both datasets have been smoothed with 121-month filters. From 1940 to present, there is a reasonable agreement between the two datasets, indicating that the underlying SST for the equatorial Pacific is impacted by the ACC and Southern Ocean SST anomalies. There does not appear to be the 7-year lag suggested by Bratcher and Giese, though.
I found the correlation between the Southeast Pacific ACC and NINO3 SST anomalies interesting, but not conclusive. And I have no explanation for the divergence between the two datasets from ~1915 to 1945. Did the North Pacific have a greater influence during those times? I can’t say. I’ll have to investigate that and the SST anomalies along the Humboldt Current in a future post to try to determine the reason for the disagreement during that period.
http://i40.tinypic.com/fw29p5.jpg
Figure 10
YET ANOTHER POST ABOUT GLOBAL TEMPERATURE RESPONSE TO ENSO
In my series of posts “Can El Nino Events Explain All of the Warming Since 1976?” I illustrated the processes that cause step changes in the East Indian and West Pacific SST anomalies, which in turn result in increased global SST anomalies. Refer to:
–Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1
–Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2
–Supplement To “Can El Nino Events Explain All Of The Warming Since 1976?”
–Supplement 2 To “Can El Nino Events Explain All Of The Warming Since 1976?”
I illustrated the similar impacts of significant ENSO events on the North Atlantic Ocean in There Are Also El Nino-Induced Step Changes In The North Atlantic.
I’ve shown how Global Surface Temperature time-series data can be replicated using natural variables in Reproducing Global Temperature Anomalies With Natural Forcings. In that post, a running total of NINO3.4 SST anomalies establishes the underlying curve.
Based on the findings of Bratcher and Giese 2002, this post presents yet another way to illustrate that ENSO dictates long-term Global Surface Temperature Anomalies.
CLOSING REMARKS – THE BIG IFS
-IF the 5-year smoothing used by Bratcher and Giese (or the 61- and 121-month smoothing that I used) reflects the underlying NINO SST anomalies, and
-IF global temperatures do respond as implied by the correlation of the NINO3 SST anomalies and Global Surface Temperature anomalies as shown in the preceding and as discussed in Bratcher and Giese 2002, and
-IF NINO3 SST anomalies continue to follow the Southern Ocean and ACC SST anomalies,
-THEN Global Surface Temperatures should continue to decrease in response.
Will these natural variations overwhelm any anthropogenic sources of warming and drive global temperatures down, as opposed to only flattening the curve as it has recently and as it had from the 1940s to the late 1970s? Only time will tell.
SOURCE
The GISS Global Surface Temperature anomaly data and the ERSST.v3b SST anomaly data are available through the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
kagiso (04:15:46) :
There is something lacking in your reasoning: Sun-Ap index-plate tectonics-volcanoes-areosols…but see the following animation on magnetic reversals:
http://www.wwnorton.com/college/geo/egeo/animations/ch2.htm
it seems that we are about one.
Keith Minto asked if an El Nino was forming? Based on the vertical stucture of anomalies in the 160-180e, 150m depth, i would guess not likely in the near future.http://www.bom.gov.au/bmrc/ocean/results/ocean_anals/NCC_Equator/2009/Feb.gif
http://www.bom.gov.au/bmrc/ocean/results/ocean_anals/NCC_Equator/2009/Feb.gif
While recently compiling a website (http://www.waclimate.net) comparing temperature trends across Western Australia from the 1800s to the present day, I kept noting signs that the 19th century was warmer than the 20th century.
The authorities dismiss such evidence from land-based temperature recording stations in Australia pre-1910 due to the unreliability of equipment preceding the Stevenson screen. Ground heat reflection on thermometers is thought to have increased recorded temperatures pre-Stevenson, although there is dispute about where and when the Stevenson or similar screens were introduced and if all pre-1910 recordings are truly invalid.
However, Australia’s Commonwealth Scientific and Research Organisation (CSIRO) issued a report in 2005 – Building a future on knowledge from the past: what palaeo-science can reveal about climate change and its potential impacts in Australia. This was a research brief for the Australian Greenhouse Office and can be downloaded at http://www.waclimate.net/palaeo-report.pdf
This report references carbon and oxygen isotope readings from core samples taken from eight central locations on the Great Barrier Reef in the south-west Pacific (source Gagan et al 2004), and the findings can be seen at http://www.waclimate.net/imgs/csiro-palaeo-temps.jpg
The top of the graphic, which extends from 1565 to 1985, shows Sea Surface Temperatures clearly higher during the 1700s and 1800s – up to .8 degrees C warmer than in the early-mid 1900s.
There’s no detail but the graph lines in Figure 1 of Bratcher and Giese from 1880 to 2000 look remarkably similar to the graph lines from Gagan et al for the same period to 1985. Maybe the Gagan graph gives a clue to Pacific Sea Surface Temperatures before 1880. Interesting notes from the CSIRO report:
Annual records of sea surface temperature for regions around northern and western Australia have been derived from coral records (Figure 4). Current integration of these records suggests that, in contrast to the Northern Hemisphere temperature reconstructions (Mann and Jones 2003), SST in the tropical southwest Pacific during the latter part of the Little Ice Age (17th-19th centuries) were as warm as the early 1980s (Gagan et al. 2004). A conflicting SST coral record has been derived from New Caledonia, suggesting a 1.4°C cooling around AD 1730. It has been postulated that the apparent regional differences in the temperature records for the Little Ice Age is the result of significant shifts in the ocean-atmosphere system
during this period, with temperature gradients between tropical low latitudes and mid-to-high latitudes being greater during the Little Ice Age (Hendy et al. 2002). Tree ring records from Tasmania (ed – about 2,000km south of the Great Barrier Reef), however, do suggest cooling during the Little Ice Age (Briffa 2000; Cook et al. 2000), supporting the concept of regional variation. Past variation in precipitation, sunlight hours and CO2 can also be inferred from Tasmanian tree ring records, although the interpretation is far more complicated.
Bob Tisdale. Good analysis. My only experience with filters is in doing commodity futures and stock market analysis. Although the filters are expressed in days/weeks/months/years. It is my experience that the same filter can not be used at all times. It has been observed over several centuries that prices make 80% of their move in 20% of the time, i.e. a series of spasms. There are times when a long filter,i.e. monthly or yearly, is best. There are other times when a daily or weekly is best. It is an axiom of investing that ” prices take the escalator up and the elevator down”. Hence at market tops a shorter filter,i.e. daily or weekly, will prevent giving up serious gain before a change in trend is apparent. In looking at temperatures, over geological time periods, of the last million years,they take the escalator down and the elevator up, with a bias to cold.
I have serious issues with any work that draws conclusions from sea surface temp rises and uses a marriage of different data sources spanning satellite data and proxy/instrument data. There are 2 serious caveats, in my opinion, that I hear very little about:
1. IR satellite measurements do not work when there is could cover, but in situ obs and proxies do. In-situ observations occur under any sky conditions. Additionally, cloud masking algorithms have been steadily improving over the last 30 years. More good data being retained and less cloud contaminated pixels getting into the record. Anyone care to guess how trends might change if you only measure temps with clear skies (admittedly both day and night)?
2. Bucket thermometer methods and buoy sensors do not measure only the top 2 millimeters of the water, but IR satellite spectrometers and radiometers do. In the satellite community, it is sometimes called skin temperature, to make the distinction clear. Take a look at SST from MODIS and compare to buoys sometime. They do not always match and when they are off, it is usually the buoy measuring 1 meter down 1 degree C colder than the IR satellite data. This is common, normal, and not a deficient satellite instrument nor buoy sensor. It is akin to a hypothetical: What if the NWS changed the requirement such that all climate stations had to measure temps at 10 meters. We would see a cooling trend (except when an inversion is present), all else being equal.
So, for our amazingly coincident rise in SST at exactly the same time that we began measuring it via satellite, I postulate that it is at least partially a product of changing depths at which it is measured and switching from an any-sky condition to [mostly] only when cloud-free.
I’ve been trying to resolve a ‘chicken and egg’ issue in relation to changes in total cloud cover and consequent albedo changes for some time.
The issue is whether ocean cycles are driven by changes in cloud cover or vice versa.
It seems logical that if the ocean cycle is the driver then if the ocean SSTs fall then the air will cool. Cooler air holds less water vapour so more vapour will condense out into clouds and the cooling trend will be enhanced by reduced sunlight.
If the ocean SSts rise then the air will warm and since warmer air will hold more water as vapour then cloudiness will decrease and the warming effect will be enhanced by extra sunlight.
Alternatively if changes in albedo and cloudiness are the driver perhaps following the Svensmark cosmic ray idea then the cosmic ray changes would be driving the ocean cycles.
However we have already seen that the global changes in temperature trends do not neatly fit solar variation. To get a better fit one has to combine solar variation with ocean cycles.
That implies that the ocean cycles operate independently of the cosmic ray effect and may be the main driver of both temperature AND cloudiness/ albedo changes with any cosmic ray effect being insignificant.
I await a resolution of that tricky point in due course but would welcome opinions in the meantime.
Pamela Gray:
Robert, of course it’s the Sun that warms the oceans. The Sun warms the oceans. It even warms the land. And melts ice. The question is what causes the variations and trends in temperature. The Sun, when measured outside of Earth’s atmosphere, is a steady state entity compared to the Earth. The Earth, on the other hand, is filled with variations. You can even see these variations from outside the atmosphere looking in. It looks nothing like a steady state ball. If there were a tongue we could put a thermometer under and measure both the Earth and the Sun, the Sun’s temp would be fairly steady. Earth’s temp would bounce and ping around. The only orb that varies to the degree that the temperature varies is the Earth. Therefore there is something about Earth that takes the heat from the Sun and causes it to jitter about and trend up and down.
It’s not the surface temperature of the sun that varies, it’s the solar activity (sunspots, etc.). Periods of low activity allow more cosmic rays to penetrate deeper into the atmosphere, which in turns causes a cloudier, cooler earth. For an example of what this can do to global temperatures Google little ice age maunder minimum.
The sun is currently in a sustained period of low activity, if it continues long enough we will all be wishing that CO2 emissions actually do cause global warming.
The pacific ACC originates again in the pacific warm pool, that is a round movement like a dog after its tail, when it is hot there it goes to the south pole to refresh and go up following the SA west coast. This is because the earth rotates from west to east, so climatologists seem to follow the same movement!
Then not to be fool: Raise our heads and look to the source of the heat.
It´s the sun buddy.
Chris Gillham (07:01:25) :The following graph of temperatures from 1754 to 1856, in Lima (Lat: 12°02´, Long:77°01) will be useful too.
http://www.giurfa.com/lima.jpg
There was a peak temperature in 1805.
How about all that garbage floating in the oceans acting as heatsinks?
Very very interesting article, it ‘ll be reported in my blog!
Meanwhille: http://72.14.221.132/translate_c?hl=it&sl=it&tl=en&u=http://daltonsminima.wordpress.com/2009/04/11/raggiunti-i-600-giorni-spotless-totali/&prev=hp&usg=ALkJrhinsKC-erLof6TwhswMpaZGO1EpEQ
Bob,
Your hypothesis is that global warming is due to a change in cloud cover over the Pacific. Could you put some numbers in to this to show that the energy injected by this change is sufficient to cause a global temperature excursion of the magnitude that is observed?
Also, what do you think caused this change in cloud cover?
Good post. This reminds me of a paper published back in 2005 by Drs. Nicola Scafetta (Duke) and Bruce J. West (US Army Research Office) titled “Estimate solar contribution to the global surface warming using the ACRIM TSI satellite composite”.
http://arxiv.org/PS_cache/physics/pdf/0509/0509248v1.pdf
Their approach “attempts to estimate the climate sensitivity to solar variation by directly studying the signature of the solar cycles within the temperature data. This is a phenomenological approach but it has the advantage of evaluating the total effect of the Sun-Climate coupling without requiring a detailed knowledge of the underlying physical and chemical mechanisms.” And without relying on climate models.
Their analysis shows that the earth’s surface temperature response lags the Hale [22-year] solar cycles since 1900 by approximately 2.2 ± 2 years.
“In conclusion, we believe our estimates Z7 and Z8 of the climate sensitivity to solar variations from 1980 to 2002 are realistic. By using the ACRIM TSI increase estimate deta_Isun (1), the climate sensitivity Z8 in Eq. (6) and Eq. (3), the warming caused by delta_Isun is delta_Tsun >~= 0.08±0.03. Thus, because the global surface warming during the period 1980-2002 was delta_T1980−2002 = 0.40±0.04 K, we conclude that according to the ACRIM TSI composite the Sun may have minimally contributed ~10-30% of the 1980-2002 global surface warming”.
Drs. Scafetta and West used global surface temperature instead of ocean surface temperature noting that “over land the climate response to solar variation is stronger than over ocean”.
–Mike Ramsey
Frank Mosher (07:08:26) :
Frank,
You might be interested in how Drs. Scafetta and West used filters. See my previous post, Mike Ramsey (09:51:22)
–Mike Ramsey
In geological courses many years ago, it was taught that the earth’s interior also played a role in the planet’s heating. Indeed, it can’t be disputed that (a)the convective upwellings along the mid Atlantic ridge (Iceland was born of volcanoes and continues to be volcanically active with accompanying geothermal waters, etc.), (b) friction between moving tectonic plates – the entire boundary of the Pacific Ocean well known as the ring of fire – and (c) hot fumarole – type activity which has deposited base and precious metal deposits and continues to so on the sea floor (Red Sea, etc) are not inconsiderable. Another heavy weight interior source is radioactive decay (every ton of lead in the earth is a decay product) which is thought to be sufficient to maintain the interior of the earth’s temperature despite conductance of heat from the core to the surface (another interior heat source that makes it necessary to air condition deep gold mines in South Africa to keep them cooler than 35C or 95F) – otherwise the earth would have cooled and the core solidified at some time during its 5billion year history. If interior heat sources are significant – and this seems a reasonable proposition for someone who has jumped into the Liard Hot Springs in northern British Columbia in January, then the sun, with all the modifications by atmosphere, land and oceans, discussed in the various threads of all the blogs is like the icing on the earth’s energy cake. The sun and the transport by air and sea doesn’t have to do all the heavy lifting to warm the oceans, etc. It can have grander effects with its modest variations in solar output simply acting on the surface, and we can stop fretting about the difficulties of heating 100s of millions of cubic kilometres of sea water and accounting for each joule that hits the surface and may or may not bounce back. Also, considering this enormous (generally unconsidered) source of heat, a few hundred grams per tonne of atmospheric CO2 being so important seems, to a geologist, a little silly. The whole debate got left too long with oceanographers, meteorologists, solar physicists and other “surface” specialists and now we have green socialists just about taking over the world.
I’m not a climatogist*, I’m a civil engineer who has spent 45 years designing and building hydroelectric projects around the world.
The first time I became aware of El Niño was in Northern Peru in 1983 when we were blindsided by the 82-83 event which produced torrential rains in an arid area and which caused landslides which delayed our project completion by more than 3 years.
My investigations following that event revealed that the people in northern Peru expect El Niño around Christmas every year (El Niño = Christ child). La Niña is a post 1983 invention.
I also learned that paleohydrological investigations in Northern Peru had identified other major occurrences over the past 2000 years. I would like to know if any of these paleohydrology studies have ever been incorporated into climate models.
Jack
*I have to ask myself if there is such a thing as a climatologist. It seems that most are physicists, astronomers or compugeeks. Very few are geologists, hydrologist, seismologists, any kind of earth scientists or other people who have real experience with what has happened in our past
Tom P: You asked, “Could you put some numbers in to this to show that the energy injected by this change is sufficient to cause a global temperature excursion of the magnitude that is observed?”
I have looked for but have been unable to find any information about, say for example, how much SST and subsurface temperature would rise in response to a 25 watt/meter^2 increase in downwelling shortwave radiation. Do you know of a source?
BTW, in the paper by Pavlakis et al that I linked in my last reply, that was the change in DSR (25watts/meter^2) over the Pacific Warm Pool during the 1997/98 El Nino. Refer to Figure 8 in Pavlakis et al.
And you asked, “Also, what do you think caused this change in cloud cover?”
I haven’t investigated it. Would you have any thoughts?
Regards.
Bob,
“I have looked for but have been unable to find any information about, say for example, how much SST and subsurface temperature would rise in response to a 25 watt/meter^2 increase in downwelling shortwave radiation.”
Then it’s rather difficult to agree with your suggestion that you might have identified a natural source for the observed warming trend.
“And you asked, “Also, what do you think caused this change in cloud cover?” I haven’t investigated it. Would you have any thoughts?”
I’m afraid no reasons for what might have caused a change in the cloud cover, but there are some other suggested reasons for a change in solar forcing that have been more fully investigated.
Tom P: You wrote, “Then it’s rather difficult to agree with your suggestion that you might have identified a natural source for the observed warming trend.”
For my response I’ll simply cut and paste a comment I made at Accuweather a few months ago: What I’ve shown recently in my posts “Can El Nino Events Explain All of the Global Warming Since 1976?” (Parts 1 and 2 and the two supplements) is that El Nino events (El Nino events that are not suppressed by volcanic eruptions) cause step changes (increases) in the East Indian and West Pacific SST anomalies. This has never been discussed in any research paper. If it has, I could not find it. Think about this for a moment: The East Indian and West Pacific Oceans that have those step changes represent between 25 to 30% of the global ocean between 60S and 65N, yet the step changes aren’t accounted for by any climate study. Are the El Nino-induced step changes enough to explain all of the SST warming since 1910? Since GCMs have not addressed this and apparently can’t address it, I can’t answer the question…and no one else can.
Let me add to that: Until GCMs can reproduce the magnitude and frequency of ENSO events and reproduce the multitude of processes (before, during, and after) that initiate and are responses to those ENSO events on monthly, annual and decadal bases, GCMs have little predictive value. They simply answer a what-if scenario (what they were designed to do) in a fantasy world that has no basis in reality.
And you wrote, “I’m afraid no reasons for what might have caused a change in the cloud cover, but there are some other suggested reasons for a change in solar forcing that have been more fully investigated.”
And they are?
Bob,
If El Niños are responsible for all the global warming, it rather begs the question as to where they are getting all of this additional energy. The oceans cannot be the ultimate source here, and that is why there are no publications which make such a claim.
Tom P: You wrote, “If El Niños are responsible for all the global warming, it rather begs the question as to where they are getting all of this additional energy. ”
And we complete the circle.
But you didn’t respond to the closing question in my last reply.
You continued, “The oceans cannot be the ultimate source here, and that is why there are no publications which make such a claim.”
If and when GCMs are capable of recreating the factors that contribute to ENSO and if and when they are able to reproduce the multiyear impacts of a single event on global climate, that might change.
Only time will tell.
Regards.
Bob T, Tom P
I think I may have a mechanism for the El Nino heat. In a post above, I suggested that geothermal flux from the interior has been essentially ignored (or dismissed as too minor). The fact there has been much made of the variations of the solar cycle heat which is only 0.2W per m2 suggests that geothermal flux deserves consideration. I won’t go far into arguments why I believe that geophysicists have underestimated the flux (major stable cratons that are centred on the Precambrian shields of the continents are comparitively cool being over the cool return cycle of the convective currents in the mantle that rise up hot under the mid ocean ridges and these are where most calculations of geothermal flux have been made. Also, the friction of the plate margins around the pacific “ring of fire” generate heat and the basaltic ocean crust is much more heat conductive than the continental granitic rocks – whew!)
Geothermal flux is generally given as 0.03W per m2 “average”. Notwithstanding my thoughts that it is an underestimate, the variation between ocean basins and continental crust is quite large. See the following and especially see where the highest flux is: 0.35W per m2 off the west coasts of South America and west of Australia.
http://geophysics.ou.edu/geomechanics/notes/heatflow/global_heat_flow.htm
Now imagine the sea water at the sea floor gathering heat at 0.35W /m2 (twenty-four hours a day not 12) until it warms, expands and wells up – also imagine the ocean currents from N and S hemispheres gathering this rising plume together and stretching it out along the equator.
Perhaps one of you is better set up to do the math to determine the time taken to heat up an adequate volume until it rises to create El Nino. Or alternatively tear the idea apart.
From what I have read, cosmic ray fluctuations are an iffy correlation to cloud formation. Forbush events do not correlate well with cloud formation but that could be due to the transient nature of these events. Cosmic ray elevation during solar minimum is also iffy since there is not good historical agreement with solar minimum evidence and temperature decreases. If you keep guessing that it is 12:00, and you guess every minute, eventually you will get it right. That does not a correlation make. Even if cloud formation eventually shows correlation with solar cycle minimum, the cloud formation that occurs may depend on oceanic oscillation conditions here on Earth in order for those clouds to do anything. The Sun is relatively steady state, the Earth is a highly variable, chaotically noisy, and oscillating entity. The greater affect is still, IMO, oceanic oscillations.
If El Niños are responsible for all the global warming, it rather begs the question as to where they are getting all of this additional energy. The oceans cannot be the ultimate source here, and that is why there are no publications which make such a claim.
If electrolytic capacitors are responsible for all that power coming out of the speakers, it rather begs the question of where they are getting all this additional energy.