Guest post by Bob Tisdale
[This is a follow up post to the first one on WUWT where Bob first examined the recent OHC revision, seen below – Anthony]
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This post presents:
1. A brief look at impact of the revisions (corrections) to the 2006-and-later OHC data
2. OHC Trend Comparisons for individual ocean basins and hemispheres
3. An update of the global, hemispheric, and basin OHC data through December 2009
A Note About The Data Presented In This Post: This data used in the graphs (except Figure 2) was downloaded through the KNMI Climate Explorer website, which allows users to define the coordinates of the desired data subset. The data is presented in Gigajoules per square meter (GJ/m^2), not in 10^22 Joules like the NODC. In the GJ/m^2 format, subsets are easier to compare, since adjustments for surface area do not have to be made (they’ve already been made). The NODC presents quarterly data. KNMI includes those quarterly values for each corresponding month. This “squares off” the monthly data in the graphs, since the one value is the same for three consecutive months, but it permits comparisons to other monthly datasets, such as NINO3.4 SST anomalies.
REVISIONS (Corrections) TO THE 2006-AND-LATER NODC OHC DATA
I provided a quick introduction to the revisions (corrections) to the 2006-and-later OHC data in my recent post NODC Ocean Heat Content (0-700 Meters) – 2007, 2008 & 2009 Corrections. In that post, I had not noticed that the 2006 data had also been revised.
Figure 1 is a time-series graph of the updated and revised Global OHC data. The cell in the upper right-hand corner shows an earlier version, before the revisions to the 2006-and-later data. I have found nothing in the NODC OHC web pages that discuss these new corrections. Are they more corrections for ARGO biases?
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Figure 1
The revisions to the 2006-and-later data shown in Figure 1 had little impact on the overall rise in the data since 1955. To confirm this, as illustrated in Figure 4 of this post, the linear trend of the revised and updated data for January 1955 through December 2009 is 0.078 GJ/meter^2/ decade. Before the revisions to the 2006-and-later data, the linear trend for the same period (not shown) was 0.079 GJ/meter^2/ decade.
-HOWEVER-
The revisions to the recent data do impact the trend of the short-term data used to illustrate the divergence between the observations and the GISS projections. This was discussed in the post NODC Ocean Heat Content (0-700 Meters) Versus GISS Projections (Corrected). In a communication with Roger Pielke Sr., James Hansen of GISS predicted an OHC accumulation of approximately 0.98*10^22 Joules per year. But the trend of the current version of the NODC OHC data (the observations) is approximately 1.5% of that GISS projection. That is, GISS projected a significant rise, while the observations have flattened significantly in recent years. The reasons for the divergence between observations and the GISS Projection were discussed in Why Are OHC Observations (0-700m) Diverging From GISS Projections? In short, GISS appears to have based its projection on the rise in OHC from the early 1990s to the early 2000s, assuming the rise was caused by changes in manmade factors and that the effect of those anthropogenic forcings would continue unabated into the future. But GISS failed to consider that the vast majority of the rise during the early 1990s to the early 2000s was caused by natural variables such as El Nino/La Nina events, the North Atlantic Oscillation, and the like, not by manmade forcings.
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Figure 2
The earlier version of that graph…
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…shows a linear trend of ~0.08*10^22 Joules/year. The current linear trend is ~0.015*10^22 Joules/year.
TREND COMPARISONS
In the numerous posts on the NODC OHC data that precede this one, I don’t believe I’ve presented linear trend comparisons. Looking at the OHC linear trends for the individual ocean basins, Figure 3, it is very evident that the North Atlantic played a major role in the rise of global OHC since the early-to-mid 1970s. The linear trends of the OHC for most ocean basins, excluding the North and South Atlantic, are between 0.047 and 0.066 GJ/meter^2/decade. The linear trend of the North Atlantic OHC (0.205 GJ/meter^2/decade), on the other hand, is approximately 3 to 4 times those values. The South Atlantic OHC trend falls in between, suggesting an influence of the North Atlantic on the South Atlantic.
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Figure 3
BIG IFS
IF the multi-decade variations in North Atlantic OHC are similar in timing to the AMO, and IF the AMO did peak in 2005, and IF (lots of big IFs) the decline in North Atlantic OHC persists for another two plus decades, will global OHC continue to remain flat (or decline) for that long, too? Many of the other ocean basins are showing recent flattening or declines, so the North Atlantic is not alone. Regardless, a long-term decline in North Atlantic OHC (if one were to occur) would definitely not help long-term projections of a monotonous rise in OHC. And since the only variables that appear to cause significant rises in the other ocean basins are multiyear La Nina events and shifts in sea level pressure, a continued drop in North Atlantic OHC would have to be counteracted by one of those other factors.
The following are links to earlier posts that illustrate and discuss how natural variables (including ENSO events and changes in sea level pressure as represented by the North Atlantic Oscillation and North Pacific Index) are responsible for most of the rise in OHC since 1955:
ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data,
AND
North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables,
AND
North Pacific Ocean Heat Content Shift In The Late 1980s
Figures 4 through 6 are comparison graphs of global and hemispheric OHC linear trends and the OHC linear trends for the individual ocean subsets per hemisphere.
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Figure 4
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Figure 5
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Figure 6
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GLOBAL, HEMISPHERIC, AND INDIVIDUAL BASIN OHC UPDATE THROUGH DECEMBER 2009
For those who enjoy information overload, the following are time-series graphs of OHC data (0-700 meters) for the globe, hemispheres, and the individual ocean basins.
Note: I have no plans to perform comparisons of the data for the individual basin OHC anomalies before and after the revisions to the 2006-and-later data. I have compared the graphs I have on file, and the revisions do appear to have impacted all ocean basins. For those who wish to confirm this, you would have to download all of the following graphs, and also download the graphs from the post Update NODC (Levitus et al 2009) OHC Data Through June 2009 (Corrected). The color coding for the ocean basins have remained the same, with the exception of the Southern Ocean. The sizes of the images may vary slightly, but the corrections are still visible.
One last note: As opposed to presenting the OHC for the NINO3.4 region of the equatorial Pacific, I’ve included Tropical Pacific OHC data in the update. Here are graphs of the updated data without commentary:
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Figure 7 – Global OHC
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Figure 8 – Northern Hemisphere OHC
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Figure 9 – Southern Hemisphere OHC
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Figure 10 – Tropical Pacific OHC
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Figure 11 – North Atlantic OHC
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Figure 12 – South Atlantic OHC
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Figure 13 – North Pacific
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Figure 14 – South Pacific
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Figure 15 – Indian Ocean
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Figure 16 – Arctic Ocean
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Figure 17 – Southern Ocean
SOURCES
NODC Annual Global OHC data used in Figure 2 is available here:
The other graphs of NODC OHC data were created from data provided by the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
George E. Smith: The first illustration at the top of the thread is a “before and after” gif animation of the graph that is shown at the NODC website here:
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
The three-month average curve represents the quarterly average OHC data (J-F-M, A-M-J, etc) they provide through links at this web page that are identified as “3-month heat content from 1955 to present”:
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html
The same webpage also provides links to the “Yearly heat content from 1955 to 2009”, which are the average of the four quarters for that year.
The three graphs identified as Figures 3, 5, & 6 show a note “Data Smoothed w/ 13-Month Filter.” Those have been smoothed by me with a 13-month running-average filter (6 months before, six months after).
re: ocean heat
how much heat might be added at the mid-ocean ridges from the spreading centers?
negligible?
I worked for ten years at a company that designed sensors for the weather satellites used to measure atmospheric temperatures. What these satellites actually measure directly is the heat-generated radiation coming from the relatively hot (compared to absolute zero!) atmospheric gasses as they look down at the earth from orbit. Create a list of temperature values going from the ground to the top of the earth’s atmosphere, and from it you can calculate the heat radiation you expect the satellite to see at different radiation frequencies. This what you do when you want to design a satellite instrument and you want to predict more or less what it would be seeing as it looks down at the earth. It is a tedious but straightforward calculation, done using straightforward computer programs Now, once the satellite is in orbit, what you get from it is the heat radiation at different frequencies. Can you take this heat radiation and from it calculate, using as many computers as needed, the temperature profile up through the atmosphere? It turns out this calculation is what applied mathematicians call an “ill-posed” problem, meaning that small errors in your radiation measurements — and no sensor is ever perfect — result in big, random-looking errors in your temperature measurements. The satellite people decades ago came up with a solution to this difficulty, and it involves forcing the computer programs calculating the atmospheric temperatures to take into account what we expect the atmospheric temperatures to be. The computer tries to find the closest match to the radiation data from the satellite while making small and reasonable changes away from the average “expected” atmospheric temperatures at the place and season it is looking at. By now I’m sure you can see what the problem is… if someone in a position of authority changes what the computer’s expected atmospheric temperatures are, the satellite measurements will produce different temperature estimates for the same measured heat radiation. If M&M want to keep the satellite guys honest, the way they made (eventually) the CRU scientists come clean, they should be asking for the raw sensor data coming down from the satellites, year after year, and check to see whether any trends exist in it. As long as the temperatures produced from the satellite data come from a statistical constraint on the original ill-posed problem, I would take those temperature values with a grain of salt…
D. Ch. (13:31:18) :
I worked for ten years at a company that designed sensors for the weather satellites used to measure atmospheric temperatures…..
Sounds like you had better do an article here for WUWT giving a more in depth discussion. Also try to make sure it is understandable for the naive lay people. WUWT is getting a lot move visitors these days.
Thanks for the info by the way. I always wondered how “safe” and un-corrupted that data was.
Bill DiPuccio (10:56:16) : You asked, “How accurate do you think these long term trends are given the migration from BTs et. al. to Argo?”
In Levitus et al (2009)…
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf
…they list the trends for specific periods on page 2, “The linear trends (with 95% confidence intervals) of OHC700 are 0.40*10^22 +/- 0.05 J yr-1 for 1969–2008 and is 0.27*10^22 +/- 0.04 J yr-1 for 1955–2008.”
You asked, “Does the 2003 transition jump suggest that the previous measurements were systematically too low?”
The following is a comparison of the four OHC datasets discussed and provided as reference in Levitus et al (2009):
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Though they diverge from one another from year to year, they are all in the same ballpark (scientific term) during the period of 1960 to 1995. Both Wijffels et al and Levitus et al have significant rises in 2002 and 2003. They are not the only two to use ARGO, though. Ishii and Kimoto also use ARGO and that curve doesn’t have the rise in 2002/03.
J.Hansford (10:30:03) : You asked, “You do sleep, right?”
I nap a lot. Thanks for the reminder.
Bob Tisdale (10:29:58) :
Well, since most are going off topic, I’ll do it also. WUWT and Anthony were mentioned in a Guardian article, “Detectives question climate change scientist over email leaks”:
One should expect that dealing with oceanic data requires rolling with the flow. :~D
Thank you for keeping us informed.
Tenuc (11:39:47) : You wrote, “Thanks for a useful article, Bob, the link between solar activity and lower global mean temperature looks more likely again.”
If you were to compare global mean temperature and TSI or sunspot nuimbers, you’d have a hard time coming that conclusion.
Gail Combs: You asked, “1. Why were the results revised?”
I haven’t found any discussion of the revisions anywhere.
Gail Combs (11:58:05) :
2. Is the total OHC headed down?
3. If it is headed down, for how long and how low?
Bob, would you like a borrow of my crystal ball?
David Douglass, good to see you post here, let’s get the serious conversation started.
I’m only a geologist, but, if we accept that CO2 lags global temperature rise – well that’s what I always thought – has anyone looked at this data and CO2? Or is that too simplistic? If ocean heat content is rising, is CO2 in sympathy?
Thanks Bob. What is most important, perhaps, is that they all agree that OHC flattened after 2003, despite the outlier quoted in the EPA response (von Schuckmann, Journal of Geophysical Research Oceans, September 2009, Volume 114 (C09007) : Pages 1-17.
http://www.ifremer.fr/docelec/doc/2009/publication-6802.pdf [August 21 draft])
The next couple of years will be telling.
To: D. Ch. (13:31:18) :
Really interesting to see the circularities here.
Feeling about all this: getting really unclear how much warming there has been, but does seem to have been some, if the biologists are right about species moving North etc etc.
Seems that oceans absorb heat and then burp it up again later – I guess it goes to high latitudes via atmosphere and ocean currents and is then radiated away. But these cycles must surely introduce variations in temperatures not yet fully pinned down so AGW case looks thinner and thinner? Poor old CO2 is collared for crimes he didn’t commit, just because he stands out in the crowd….
tallbloke (14:01:44) :
“Gail Combs (11:58:05) :
2. Is the total OHC headed down?
3. If it is headed down, for how long and how low?
Bob, would you like a borrow of my crystal ball?”
Tallbloke, Bob, those were all rhetorical questions. I know no one really has an answer to the last two and only NODC has an answer to the first and they are not talking.
Otherwise Bob has done a great job of explaining stuff.
D. Ch. (13:31:18) :
“…The computer tries to find the closest match to the radiation data from the satellite while making small and reasonable changes away from the average “expected” atmospheric temperatures at the place and season it is looking at. By now I’m sure you can see what the problem is… if someone in a position of authority changes what the computer’s expected atmospheric temperatures are, the satellite measurements will produce different temperature estimates for the same measured heat radiation…
Thanks for another very insightful post.
Isn’t it strange that whatever climate temperature data set you look at, it has been massaged and homogenised to meet ‘expectation’?
It’s no wonder the government institutions producing this data are unwilling/scared to provide full disclosure of raw observation, adjustment method and computer code. They seem to be creating their own reality, rather than looking at facts.
unless this unscientific procedure is halted now, we will never know what’s really happening, although we will all experience the results as weather.
No wonder
tallbloke asked, “Bob, would you like a borrow of my crystal ball?”
Can you email it to me?
Bob, Great post. I like the technical info. BTW, I think you meant “monotonic”. But that begs my question: are we seeing another step increase ala 1998? What non-linear pattern do you detect?
It’s interesting to observe that the North Atlantic heat content seems to have peaked around 2005 and may now be in a downward trend, while the Arctic heat content peaked around 2007 and may now be in a downward trend. And 2007 was the year of the extremely low Arctic sea ice extent.
Mike D: You asked, “…are we seeing another step increase ala 1998? What non-linear pattern do you detect?”
Too early to tell. The shifts become evident during the La Nina phase.
Bob, thank you for the good answer. There is much of interest at WUWT besides the sturm and drang.
D. Ch. (13:31:18) :
“if someone in a position of authority changes what the computer’s expected atmospheric temperatures are, the satellite measurements will produce different temperature..”
Tenuc
“It’s no wonder the government institutions producing this data are unwilling/scared to provide full disclosure of raw observation, adjustment method and computer code. They seem to be creating their own reality, rather than looking at facts.”
This has been worrying me for a while and my concern over the integrity of these organizations increased a lot when I realized that someone rewrote the climate history of my own country.
I feel that it is coming more and more problematic that current information monopolies exist. One place for global surface data (NCDC) and one place for all satellite data (NASA).
If someone would decide to take control of the global temperature map (surface, ocean) and adjust it a bit randomly or accroding to a plan, that would throw hundreds or thousands experts trying to find a natural explanation to what has been “observed”.
If your ‘enemy’ is a group of skeptical scientists, what would be more convenient way to put them to disarray than feeding them altered measurement data and they spend their days trying to find an explanation to phenomena which might not exist at all.
This is an old tactic used in military intelligence. If you know that your enemy is watching, it might make sense to make some troop movements, run some convoys etc. just to mix up the intelligence officers scenarios on the other side and make them spend a lot of time trying to figure out what they have just seen.
Is it really so that only satellite temperature data is from NASA? No one else (Russia, China) do not measure temperature? Or do we just have to accept that we have just one truth available?
It seems that global warming has really ramped up during Obama administration, despite the snow and freezing weather. And yes – I’m skeptical if i have just one data source available. I guess that all people who have lived in or next to former Soviet Union remember the time of the “one truth” and are inherently skeptical to data which cannot be verified elsewhere. That’s the benefit of having 30 year experience of “information management”.
Tenuc (11:39:47) :
Right, thanks for drawing the conclusion.