Introduction To The NODC Ocean Heat Content Anomaly Data For Depths Of 0-2000 Meters
The National Oceanographic Data Center (NODC) recently posted a new Ocean Heat Content (OHC) anomaly dataset on its website. It is available on annual and quarterlybases, along with the data for its standard and documented dataset that covers depths of 0-700 meters. I looked for but was not able to find any papers (in any state of publication) that supported the new OHC data for 0-2000 meters. We’ll just have to wait and see how the NODC intends to present this dataset.
The data for the depths of 0-700 meters is, of course, documented in the paper Levitus et al (2009) “Global ocean heat content (1955-2008) in light of recent instrumentation problems”. Refer to Manuscript. It was revised in 2010 as noted in the October 18, 2010 post Update And Changes To NODC Ocean Heat Content Data. As described in the NODC’s explanation of ocean heat content (OHC) data changes, the changes result from “data additions and data quality control,” from a switch in base climatology, and from revised Expendable Bathythermograph (XBT) bias calculations.
COMPARISON OF GLOBAL OHC ANOMALIES: 0-700 METERS VERSUS 0-2000 METERS
Figure 1 compares the quarterly NODC OHC anomaly data for the depths of 0-700 meters and 0-2000 meters on a global basis. As noted on the illustration, the most obvious divergence between the two datasets occurs during the ARGO era. This is the period when ARGO floats became the dominant means of sampling of ocean temperatures and salinity at depth.
Figure 1
If we limit the comparison to the period from 1970 to 1999, Figure 2, we can see that there is basically no difference in the linear trends. There are minor differences from year to year, but the two datasets appear to be basically the same. Why?
Figure 2
There are extremely few observations prior to the year 2000 at depths greater than 1000 meters. This is illustrated in Figure 3. (Note that NOAA Climate Prediction Center Data Distributionwebpage breaks down the temperature profiles into depths of 0-250 meters, 250-500 meters, 500-1000 meters and 1000-5000 meters. Those depths don’t agree with the depths presented by the NODC for its Ocean Heat Content anomaly data.)
Figure 3
And Animation 1 shows a series of annual maps of the locations of temperature profiles from 1979 to 2005 for the depths 1000-5000 meters. As illustrated, there is also very little spatial coverage at these depths until the introduction of the ARGO floats.
Animation 1
As a reference, Figure 4 shows the number of temperature profiles for depths of 250 to 500 meters. There were between 2000 to 5000 temperature profiles per month between the late 1970s and the late 1990s at these depths before the ARGO floats were deployed. Note that the TAO/TRITON project (red curve) shows temperature profiles that were initially for the equatorial Pacific (coordinates approximately 8S-9N, 137E-95W). Those buoys were deployed for the study of El Niño and La Niña events. The locations were later expanded to include portions of the Tropical Atlantic and Indian Oceans under the PIRATA and RAMA projects. Refer to the TAO Project Global Arraywebpage. So while there are a good number of temperature profiles for the TAO project, they are limited in their location.
Figure 4
Figure 5 illustrates the difference between the two NODC Global Ocean Heat Content (OHC) datasets, where the 0-700 meter data has been subtracted from the 0-2000 meter data. Also referring back to Figure 3, the difference between the two datasets seems to increase in concert with the number of temperature samples at depths greater than 1000 meters. It appears as though the divergence of the 0-2000 meter dataset from the 0-700 meter data since around 2000 could be caused by the increased number of samples at depth and the increased spatial coverage of the ARGO floats, as shown in the animations. The impacts on short-term and long-term trends of the increased number of samples at depths greater than 700 meters and the impact of the increased area of observations should be determined. (A study such as that is well beyond my capabilities.) Maybe it will be documented in the NODC paper that accompanies the 0-2000 meter dataset.
Figure 5
Keep in mind, before the ARGO era, there were very few ocean temperature observations at any depth in the Southern Hemisphere south of about 40S. For example, Animation 2 is a gif animation of maps that illustrate the locations of temperature profiles for depths of 0-250 meters, 250-500 meters, 500-1000 meters, and 1000-5000 meters for the year 1995.
Animation 2
And Animation 3 shows the same series of temperature profile maps but for the year 2005.
Animation 3
A COUPLE OF QUESTIONS FOR READERS
Were the Expendable Bathythermograph (XBT) probes with wire lengths of 760 meters the most commonly used XBT probes before the ARGO era? Is this the reason the NODC originally limited the depth to 700 meters for the Ocean Heat Content anomaly data? Does anyone recall a paper that presents this? I had always assumed the depth of 700 meters was selected due to the number of and locations of observations, but I have never seen it stated in a paper.
LONG-TERM TRENDS PER OCEAN BASIN
When I originally prepared the graphs for this post, I could find no reason to present the long-term trends for the individual ocean basins of the 0-2000 meter data. The reason being, in some respects, the NODC OHC data for 0-2000 meters appears to me to simply be a 0-2000 meter OHC dataset spliced onto a 0-700 meter dataset. But on further thought, my failure to present the data might be thought by some as an attempt on my part to hide something. So Figure 6 (0-2000 meters) and Figure 7 (0-700 meters) are long-term trend comparisons of the Ocean Heat Content anomalies for the individual ocean basins as presented by the NODC. The most obvious similarity is that the long-term trends of the North Atlantic Ocean Heat Content are significantly higher than other ocean basins in both datasets, and in both, the North Atlantic Ocean Heat Content peaked in 2004. After that, there are significant declines. One would think this would lead researchers to examine the effects of the Atlantic Multidecadal Oscillation and Meridional Overturning Circulation on North Atlantic Ocean Heat Content observational data, yet, as far as I know, this is an area unexplored by climate scientists.
Figure 6
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Figure 7
ARGO-ERA TRENDS PER OCEAN BASIN
The ARGO-era (2003 to present) linear trends per ocean basin for the depths of 0-2000 meters and 0-700 meters are shown in Figure 8 and 9, respectively. Like the trends for the 0-700 meter data, the South Atlantic and Indian Ocean are the only basins with significantly positive linear trends for the 0-2000 meter Ocean Heat Content data. And also like the trends 0-700 meter data, the linear trends of the 0-2000 meter Ocean Heat Content anomalies in the North Atlantic and South Pacific are negative. The linear trends for those two ocean basins are less negative for 0-2000 meter depths than they are for 0-700 meter depths, indicating that the declines at depths of 0-700 meters are greater than the increases at the 700-2000 meter depths. Considering there is less than a decade of ARGO-era data with “full” coverage, there is no need to speculate about the cause. Note also that the trend for the North Pacific OHC anomalies is basically flat for the 0-2000 meter data, and that the same holds true for the 0-700 meter data.
Figure 8
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Figure 9
CLOSING COMMENTS
The undocumented (as of this writing) NODC 0-2000 meter Ocean Heat Content dataset appears as though it was prepared to show that Global Ocean Heat Content continues to rise during the ARGO era, and that it is intended to counter the argument that Global Ocean Heat Content has flattened during the ARGO era as shown in the NODC 0-700 meter dataset.
Due to the extremely limited number of observations at depths of 1000-5000 meters (shown in Figure 3 and in the animations), the 0-2000 meter Ocean Heat Content dataset should be used with great caution. It appears to me to be an ARGO-era 0-2000 meter Ocean Heat Content dataset spliced onto a long-term 0-700 meter dataset. For this reason, I, personally, would not expend the effort to analyze the long-term (pre-ARGO era) 0-2000 meter NODC OHC data beyond what has been presented in this post.
Each time I see the claim (based on many assumptions) by anthropogenic global warming proponent scientists that the rise in ocean heat content at depth “will come back to haunt us” I wonder why those same scientists have not bothered to attempt to document how much of the rise in OHC from the 1970s to the early 2000s (0-700 meters) was caused by the deep oceans upwelling warmer anomalies from past decades, other than the fact that there’s no data for them to do so. Could they believe that multidecadal variability is limited to Sea Surface Temperatures and does not impact temperatures at depth? Or is their intent to have the unsuspecting public believe it?
Thanks, Anthony.
Obviously they are doing this to support the theory that the “heat has gone to the deep layers” nonsense that was proposed last month.
Thanks Bob, still reading, but thank you for “watching the pea”!
I’m not going to state deepest depths because that is classified but evey submarine has recorded depth v temp v position every hour on the hour ever since submarines became part of the world’s Navies. Watch keeping is what the Navy does best. The info is on record but probably not available….yet.
Thanks Bob.
Interesting. Forewarned is forearmed. Regardless, expect the NOAA press release and media blitz prior to Durban and AR5….
Talking of which, shouldn’t we be expecting GISS to announce their full=year 2011 temperature anomaly pretty soon? 😉
Anthony, could you change the color choices for the first two figures, they are not color blind friendly.
They are so similar (same color family, nearly the same gray tone) a person who is red green color blind cannot tell them apart visually. Different color families would be best, ie one of them blue for example.
Larry
So that’s where Trenberth’s missing heat went!
Given the amount of water, wouldn’t it be possible to park a lot of heat down there with an immeasurable temperature rise? I think I once worked out that if all the energy generated by man for 1 year went directly to the ocean we would be able to raise its temperature by ~10µK.
At what resolution do Argo floats measure temperature?
You have got to be effing kidding.
0-700 tracks 0-2,000 without fail, until it magically diverges *exactly* when needed to ‘find’ the missing heat?
Fabricating with impunity.
A COUPLE OF QUESTIONS FOR READERS
Were the Expendable Bathythermograph (XBT) probes with wire lengths of 760 meters the most commonly used XBT probes before the ARGO era? Is this the reason the NODC originally limited the depth to 700 meters for the Ocean Heat Content anomaly data? Does anyone recall a paper that presents this? I had always assumed the depth of 700 meters was selected due to the number of and locations of observations, but I have never seen it stated in a paper.
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I think I have read somewhere that it represents the depth at which the temperature profile flattens out. So the cable lengths are therefore dictated by this rather than the other way around.
Don’t know for sure.
So, the IPCC will soon be accusing Earth of sweeping the anthropogenic heat “under the rug”, so to speak?
Thanks Bob!
The undocumented (as of this writing) NODC 0-2000 meter Ocean Heat Content dataset appears as though it was prepared to show that Global Ocean Heat Content continues to rise during the ARGO era, and that it is intended to counter the argument that Global Ocean Heat Content has flattened during the ARGO era as shown in the NODC 0-700 meter dataset.
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So your saying the data or analysis is faked.
I thought it was to resolve known problems in the energy budget of the earth.
So here is my suggestion. Set up a study controlled by you and funded by the Koch brothers. This will prove that those Argo guys are incompetent frauds.
Record too short. Period. Basically meaningless.
I didn’t see heat energy converted to temperature in this post. So I attempted to do that on my own. Somebody please check my numbers. I get total ocean volume at 1.3E9 km3, which is 1.3E 18 m3, which in turn is 1.3E21 kg of water. The specific heat content of water is 1.8 kJ/kg*K. Therefore, the specific heat content of the oceans is 2.3E24 J/K. The biggest anomaly number I see in the paper is 4E22 J. This is .017 degrees C.
Either I did something wrong (like assume too big a volume because the deep ocean doesn’t get warmer) or somebody has a far different understanding of our ability to measure temperature.
There also appears to be some centering mischief going on. Notice how the first 15 – 20 years shows the 0-2000 m OHC anomaly is slightly below the 0-700 m anomaly. Where have we seen that before?
hotrod (Larry L): Sorry. Will blue and red work for you? I’ll change them at the cross post at my website for you as soon as you give me an okay.
Can you imagine a drug company trying to do this with a medication?
The CEO would be in front of Congress within 24 hours.
LazyTeenager says: “So your [sic] saying the data or analysis is faked…”
Your response to my post is nonsensical. Please advise where in it I stated or implied that the NODC OHC data at any depth has been faked. If you would have read the opening paragraph of the post, you would have noticed that I noted that the NODC published the data before the paper with: “I looked for but was not able to find any papers (in any state of publication) that supported the new OHC data for 0-2000 meters. We’ll just have to wait and see how the NODC intends to present this dataset.”
Take your nonsense elsewhere. You and your ilk bore me.
Yes that will work very well. Almost no one is colorblind to blue (only true black and white colorblind have issues with blue). Approximately 10% of the males of northern European heritage have some degree of red-green colorblindness. Color pairs which are very difficult for us to tell apart are reds and dark oranges, dark greens and dark browns, dark blues and purples, very pale greens and yellow etc.
I am almost completely blind to light shades of cyan, and have subdued sensitivity to red, so very dark reds or colors which have red in them if dark are easily confused.
Thanks for the change. I sometimes can sort these charts out with colorblind tools like “colorzilla” addon in firefox or “whatcolor” but it is a big pain to do that especially on small charts as it is hard to center the cursor over the color trace, and sometimes the color key in the chart is not really the exact same color as the traces in the chart.
Larry
1.0 Watt/m2 over the entire Earth over 1 year equals 1.61 10^22 joules.
1.0 Watt/m2 over a year absorbed in the Oceans would by 1.13 10^22 joules
Since there has been little surface warming in the Argo era, the extra forcing from GHGs/Human-made had to be going to be somewhere – either directly back into space, or into the oceans, or into ice sheet melt/land accumulation (estimated to be about 0.1 watts/m2).
The IPCC said that the direct GHG/Human-made forcing in 2007 was +1.6 Watts/m2 (and it would be a little bit higher in 2010).
So where did the extra 2.58 10^22 joules go in 2010?
—> 0.0 went into surface temperature warming.
—> 0.16 10^22 went into ice sheet melt/land accumulation
—> -0.05 10^22 went into the 0-700 metre ocean
—> 0.6 10^22 went into the 700-2000 metre ocean (according to the new data).
That leaves the Earth 1.87 10^22 joules short or about 1.16 watts/m2 short. Space anyone? The energy is still missing.
They need a graph of ocean heat content for AR5, i Guess, and the old one just wasnt “promoting the message” sufficiently…
Bob, outstanding work as always.
I suspect the Indian ocean increasing OHC is due to decadal monsoon cycles.
Googling around, I find remarkably little work has been done on this. Surprising since India will have good rainfall records going back over a century.
Without the Indian Ocean, Argo shows declining OHC in the Argo era down to 700 meters.
And Argo is the best climate data we have.
I agree with you that below 700m pre-Argo data probably isn’t worth much. Kinda like grafting tree ring data onto the thermometer record.
hotrod (Larry L), per your request, red and blue for the first two graphs:
http://bobtisdale.wordpress.com/2011/10/24/introduction-to-the-nodc-ocean-heat-content-anomaly-data-for-depths-of-0-2000-meters/
Bob:
A bit OT, but related to ocean temperature measurement.
I’ve been wrestling with a question over the last number of weeks. The question is: Why is the ocean so cold? 5,000 meters below the bottom of the ocean, the rock temperature is in the range of 800 kelvin. Temperature of the ocean at the bottom of the ocean is about 275 kelvin for a gradient of 525 k per 5000 meters or 105 kelvin per kilometer. This is about 4 times higher than the continental crust. The ocean is sucking heat out of the crust very quickly. (Still a very small flux compared to solar radiation, but a constant positive flux none the less. In addition, the surface of the planet (we are told) is, on average about 290 kelvin. So heated from above, heated from below, but colder than both. Below makes sense because cold water sinks. But sooner or later, the ocean should reach equilibrium with the atmosphere and crust. Note that for oceans, the worst of the arctic and antarctic cold is insulated by a layer of ice while the worst of the tropical heat is deeply mixed every time there is a tropical cyclone. The more I think about it, the less it makes sense. If deep mixing of the arctic / antarctic cold water is the answer, then wouldn’t this imply that the net surface temperature of the fluid cover of the earth (atmosphere plus hydrosphere) is cold. Perhaps as low as 280k? That is, is this the equilibrium temperature? I don’t want to go there because, as Dr. Curry would point out, there be dragons.
If we are to follow Dr. Pielke sr’s view, we should be looking at energy content, not flux. And looking at energy content brings us closer to the land of the dragons, because the top 14 meters of the ocean has the same mass as the entire atmosphere and I believe water is a better store of energy. As I said. It is a struggle.
If Trenberth postulates that the ‘heat is in the deep’ then sure enough, thats where it will show up.
Bingo.
Still now explanation as to how it got there …. or why there hasn’t been the requisite amount of thermal expansion.
Thanks for the color change in the charts Bob much much better!
Given that graphic display of data is such a fundamental part of the discussions that show up here on WUWT, perhaps Anthony could find someone who could present a topic on colorblind friendly data representation for the web and print.
It is a grossly under appreciated subject. Most technical documents take it for granted that their users have normal color vision (as do manufactures of technical equipment who use colored warning lights to indicate problems).
On the old Solaris hardware it was physically impossible for me to distinguish between the green LED that said all was happy and the yellow LED that said it had a problem. Even if I stood directly in front of the server and already knew it had a warning light, I still could not discern a difference between the LED colors. It is interesting that many technical careers require normal color vision, so those of us who have atypical color vision tend to get pushed into technical careers that do no have a formal color vision requirement.
As a result of that tendency to concentrate in certain fields our crew had 4 people on it, 3 Caucasian males (all of which were red green color blind) and one woman. She got to check a lot of warning lights because she was the only person on our team with normal color vision. Luckily at the time, Solaris included a command (prtdiag -v) that printed out the warning light colors so we could go to the command line and display the warning light status on servers that were alive enough to respond to command like input. For routers and switches we were stuck with what we could see. Unfortunately Solaris no longer returns that information with prtdiag -v on servers that have intel cpu’s.
This is a tangent to the topic of discussion here, so I will not comment further on this, but I would appreciate if Anthony, with the coverage that WUWT has in the technical universe made an effort to discuss this topic here, to raise awareness in the technical fields.
Larry