April to June 2011 NODC Ocean Heat Content Anomalies (0-700Meters) Update and Comments
Guest post by Bob Tisdale
A NEW APPEARANCE
Due to the noise in the Ocean Heat Content anomaly data for some of the ocean basins, I’ve added 13-month running average filters to the long-term graphs.
SAME INTRODUCTION AS ALWAYS
The National Oceanographic Data Center’s (NODC) Ocean Heat Content (OHC) anomaly data for the depths of 0-700 meters are available through the KNMI Climate Explorer Monthly observations webpage. The NODC OHC dataset is based on the Levitus et al (2009) paper “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.
The OHC anomaly data is provided from the NODC on a quarterly basis. There it is available globally and for the ocean basins in terms of 10^22 Joules. The KNMI Climate Explorer presents the quarterly data on a monthly basis. That is, the value for a quarter is provided for each of the three months that make up the quarter, which is why the data in the following graphs appear to have quarterly steps. Furnishing it in a monthly format allows one to compare the OHC data to other datasets that are available on a monthly basis. The data is also provided on a Gigajoules per square meter (GJ/m^2) basis through the KNMI Climate Explorer, which allows for direct comparisons of ocean basins, for example, without having to account for surface area.
This update includes the data through the quarter of April to June 2011.
Let’s start the post with a couple of looks at the ARGO-era OHC anomalies.
BASIN TREND COMPARISONS
Figure 1 and 2 compare OHC anomaly trends for the ocean basins, with the Atlantic and Pacific Ocean also divided by hemisphere. Figure 1 shows the ARGO-era data, starting in 2003, and Figure 2 covers the full term of the dataset, 1955 to present. The basin with the greatest short-term ARGO-era trend is the Indian Ocean, but it has a long-term trend that isn’t exceptional. (The green Indian Ocean trend line is hidden by the dark blue Arctic Ocean trend line in Figure 2.) The basin with the greatest rise since 1955 is the North Atlantic, but it also has the largest drop during the ARGO-era. Much of the long-term rise and the short-term flattening in Global OHC are caused by the North Atlantic. If the additional long-term rise and the recent short-term decline in the North Atlantic OHC are functions of additional multidecadal variability similar to the Atlantic Multidecadal Oscillation, how long will the recent flattening of the Global OHC persist? A couple of decades?
Note also in the ARGO-era graph, Figure 1, that the South Atlantic and Indian Ocean subsets are the only ocean basins with positive linear trends. The sharp decline in the North Pacific OHC anomalies during the second quarter 2011 was great enough to drop its ARGO-era trend to just below zero.
Figure 1
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Figure 2
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Further discussions of the North Atlantic OHC anomaly data refer to North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables. And if you’re investigating the impacts of natural variables on OHC anomalies, also consider North Pacific Ocean Heat Content Shift In The Late 1980s and ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data.
ARGO-ERA MODEL-DATA COMPARISON
Much of the discussion under this heading was first presented in the post January to March 2011 NODC Ocean Heat Content (0-700Meters) Update and Comments.I’ve attempted to clarify some of the points in this version.
Many of you will recall the discussions generated by the simple short-term comparison graph of the GISS climate model projection for global OHC versus the actual observations, which are comparatively flat. The graph is solely intended to show that since 2003 global ocean heat content (OHC) anomalies have not risen as fast as a GISS climate model projection. Tamino, after seeing the short-term model-data comparison graph in a few posts, wrote the unjustified Favorite Denier Tricks, or How to Hide the Incline. I responded with On Tamino’s Post “Favorite Denier Tricks Or How To Hide The Incline”. And Lucia Liljegren joined the discussion with her post Ocean Heat Content Kerfuffle. Much of Tamino’s post had to do with my zeroing the model-mean trend and OHC data in 2003.
While preparing the post GISS OHC Model Trends: One Question Answered, Another Uncovered, I reread the paper that presented the GISS Ocean Heat Content model: Hansen et al (2005), “Earth’s energy imbalance: Confirmation and implications”.Hansen et al (2005) provided a model-data comparison graph to show how well the model matched the OHC data. Figure 3 in this post is Figure 2 from that paper. As shown, they limited the years to 1993 to 2003 even though the NODC OHC data starts in 1955. Hansen et al (2005) chose 1993 as the start year for three reasons. First, they didn’t want to show how poorly the models hindcasted the early version of the NODC OHC data in the 1970s and 1980s. The models could not recreate the hump that existed in the early version of the OHC data. Second, at that time, the OHC sampling was best over the period of 1993 to 2003. Third, there were no large volcanic eruptions to perturb the data. But what struck me was how Hansen et al (2005) presented the data in their time-series graph. They appear to have zeroed the model ensemble mean and the observations at 1993.5. The very obvious reason they zeroed the data then was so to show how well OHC models matched the data from 1993 to 2003.
Figure 3
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The ARGO-era model-data comparison graph in this post, Figure 4, is also zeroed at the start year, 2003, but I’ve done that to show how poorly the models now match the data. I’m not sure why my zeroing the data in 2003 is so difficult for some people to accept. Hansen et al (2005) zeroed at 1993 to show how well the models recreated the rise in OHC from 1993 to 2003, but some bloggers attempt to criticize my graphs when I zero the data in 2003 to show how poorly the models match the data after that. The reality is, the flattening of the Global OHC anomaly data was not anticipated by those who created the models. This of course raises many questions, one of which is, if the models did not predict the flattening of the OHC data in recent years, much of which is based on the drop in North Atlantic OHC, did the models hindcast the rise properly from 1955 to 2003? Apparently not. This was discussed further in the post Why Are OHC Observations (0-700m) Diverging From GISS Projections?
Figure 4 compares the ARGO-era Ocean Heat Content observations to the model projection, which is an extension of the linear trend determined by Hansen et al (2005), for the period of 1993 to 2003. Over that period, the modeled OHC rose at 0.6 watt-years per year. I’ve converted the watt-years to Gigajoules using the conversion factor readily available through Google: 1 watt years = 31,556,926 joules. With the recent seasonal declines in Global Ocean Heat Content anomalies, the model projection is rising at a rate that’s more than 10 times higher than the observations since 2003. 10 times higher.
Figure 4
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HOW LONG UNTIL THE MODELS ARE SAID TO HAVE FAILED?
I asked the question in Figure 4, If The Observations Continue To Diverge From The Model Projection, How Many Years Are Required Until The Model Can Be Said To Have Failed? I raised a similar question in the post 2nd Quarter 2011 NODC Global OHC Anomalies last week, and in the WattsUpWithThat cross post Global Ocean Heat Content Is Still Flat, a blogger stated, in effect, that 8 ½ years was not long enough to reject the models.If we scroll up to Figure 3, Figure 2 from Hansen et al (2005), we can see that Hansen et al (2005) used only 11 years to confirm their Model E hindcast was a good match for the Global Ocean Heat Content anomaly observations. Can we then assume that the same length of time will be long enough to say the model has failed during the ARGO era?
And as noted in OHC update from last quarter, it’s really a moot point. Hansen et al (2005) shows that the model mean has little-to-no basis in reality. They describe their Figure 3 (provided here as Figure 5 in modified form) as, “Figure 3 compares the latitude-depth profile of the observed ocean heat content change with the five climate model runs and the mean of the five runs. There is a large variability among the model runs, revealing the chaotic ‘ocean weather’ fluctuations that occur on such a time scale. This variability is even more apparent in maps of change in ocean heat content (fig. S2). Yet the model runs contain essential features of observations, with deep penetration of heat anomalies at middle to high latitudes and shallower anomalies in the tropics.” I’ve deleted the illustrations of the individual model runs in Figure 5 for an easier visual comparison of the graphics of the observations and the model mean. I see no similarities between the two. None.
Figure 5
GLOBAL
The Global OHC data through June 2011 is shown in Figure 6. It continues to be remarkably flat since 2003, especially when one considers the magnitude of the rise that took place during the 1980s and 1990s from 1983 through 2003.
Figure 6
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TROPICAL PACIFIC
Figure 7 illustrates the Tropical Pacific OHC anomalies (24S-24N, 120E-90W). The major variations in tropical Pacific OHC are related to the El Niño-Southern Oscillation (ENSO). Tropical Pacific OHC drops during El Niño events and rises during La Niña events. As discussed in the update for October to December 2010, the Tropical Pacific had not as of then rebounded as one would have expected during the 2010/11 La Niña event. It finally responded a little during the first quarter of 2011, but with the drop during the most recent quarter, it appears the 2010/11 La Niña event did little to recharge the heat discharged during the 2009/10 El Nino.
Figure 7
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For more information on the effects of ENSO on global Ocean Heat Content, refer to ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data and to the animations in ARGO-Era NODC Ocean Heat Content Data (0-700 Meters) Through December 2010.
A CHANGE IN THE COORDINATES USED FOR THE NORTH ATLANTIC
I recently changed the coordinates I use for the North Atlantic in the Sea Surface Temperature anomaly updates from 0-75N, 78W-10E to 0-70N, 80W-0. I did this so that I was using the same coordinates the that NOAA/ESRL uses for their Atlantic Multidecadal Oscillation (AMO) data. I’ve now changed the coordinates I’m using in the OHC updates to 0-70N, 80W-0 for consistency between datasets. There is little difference in the OHC anomalies between the old and new coordinates as shown in Figure 8.
Figure 8
THE HEMISPHERES AND THE OCEAN BASINS
The following graphs illustrate the long-term NODC OHC anomalies for the Northern and Southern Hemispheres and for the individual ocean basins–without commentary.
(9) Northern Hemisphere
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(10) Southern Hemisphere
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(11) North Atlantic (0 to 70N, 80W to 0)
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(12) South Atlantic (0 to 60S, 70W to 20E)
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(13) North Pacific (0 to 65N, 100 to 270E, where 270E=90W)
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(14) South Pacific (0 to 60S, 120E to 290E, where 290E=70W)
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(15) Indian (60S-30N, 20E-120E)
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(16) Arctic Ocean (65 to 90N)
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(17) Southern Ocean (60 to 90S)
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AN ANIMATED COMPARISON OF OCEAN BASIN OHC ANOMALIES
I was recently asked why I did not use one scale for the y-axis in graphs of the ocean basins—that having the scale change for each basin made it difficult to compare graphs. The answer: because the rise in North Atlantic OHC anomalies is so much greater than the other ocean basins, the scale required for it skews the scaling for the other ocean basins. But for those interested, Animation 1 illustrates the OHC anomalies for each of the ocean basins, while keeping a common scale for the y-axis.
Animation 1
SOURCE
All data used in this post is available through the KNMI Climate Explorer:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
James Reid says:
September 18, 2011 at 9:13 pm
R. Gates says:
September 18, 2011 at 6:38 pm
“A useful model will be refined over and over again. Always destined to be wrong (i.e. not an exact map of reality), but ever closer to hinting at the underlyimg dynamics.”
But… a factor of 10 discrepancy? How long will it take to refine these to be close enough to justify the insane carbon tax about to be introduced in Australia? 50… 100….. maybe a 1000 years 🙂 (never?).
_____
I am not in favor of any carbon taxes. But not to worry, these will be repealed soon enough I would imagine.
R. Gates says: “So, all models fail even before they are are on the street because ALL MODELS ARE WRONG.”
Glad you wrote that, because as you are aware, I’ve illustrated that the Sea Surface Temperature anomaly hindcasts/projections have no basis in reality. Refer to:
http://bobtisdale.wordpress.com/2011/04/10/part-1-%e2%80%93-satellite-era-sea-surface-temperature-versus-ipcc-hindcastprojections/
And:
http://bobtisdale.wordpress.com/2011/04/19/492/
If they have no basis in reality, they have limited to no use as tools for making projections of future climate.
R Gates said;
“Indeed, there should be according to one hypothesis related to Earth’s energy balance. Trenberth has calculated that there seems to be about .9 wm2 “missing”, even though some recent studies have found at least a small portion of it in the deeper parts of the Pacific”
I saw your links to two studies on this subject over at climate etc and read them. To know there is a small portion of the ‘missing heat’ in the deeper parts of the Pacfic we need to have reliable historic records we can make comparisons against on a like for like basis. Can you please reference these? Thanks..
Whilst we are about it I left a reply to you on the arctic thread over there which repeated the one I made over here that you perhaps didn’t see.
tonyb
R. Gates says: “Think, for example, about the incredible amount of energy being brought down into the deepest parts of the Atlantic as the gulf stream plundges downward in the N. Atlantic.”
Check a map of North Atlantic surface currents and the locations of THC downwelling points. The downwelling points should be north of the Gulf Stream. Also, in order for the surface waters to downwell as part of THC don’t they have to be more dense than the waters at depth?
Certainly the thermohaline circulation creates downwelling in some locations and upwelling in others.
I don’t see any need to go further than that because any other processes which might have the same or a similar effect are likely to be orders of magnitude smaller in their effects and merely local or regional phenomena.
It seems entirely plausible that temperature discontinities could develop along the horizontal track of the THC in response to surface warming from reduced albedo and cloudiness which are looking more and more likely to be solar driven in a way that I have suggested elsewhere.
So if one has 500 years of increasing solar activity (such as LIA to date) steadily if unevenly imparting more energy to the upper layers I am quite sure that it would feed into the THC to some degree.
However the bulk of variability in ocean heat content would occur in the top 700 metres or so because it is so much easier for energy to flow out to the atmosphere than down to the depths. Thus I don’t think it likely that variations in subducted energy are enough to account for a significant portion of Trenberth’s ‘missing heat’.
Nevertheless the concept of such subduction and of variations in temperature along the THC is useful for another reason even if the amounts of heat are small compared to the energy exchanges near the surface.
The THC takes 1000 years or so for a full circuit so it is highly likely that temperature variations along its track would eventually result in temperature variations when it upwells again 1000 years or so later.
Such variations would likely be long and slow and would impose an effect on the energy content of the upper layers independent of whatever was happening near the surface at the time.
That leads to the issue of CO2 absorption capabilities of the oceans where slightly warmer upwelling occurs slowly and over a long period of time as a result of solar heating from 1000 years previously. Clearly, absorption capability would be reduced if slightly warmer water is upwelling and that would be superimposed on whatever were to be going on at the surface at the time. Indeed it could well impose just such a persistent stable trend in atmospheric CO2 quantities as that which we currently see at Mauna Loa.
I think that is a neat hypothesis that deserves investigation especially if it is now being proposed that any part of near surface warming does get subducted into the deeps by whatever process.
The alarmist ideology cannot have it all ways. If they need energy subduction to save their theories about ‘missing heat’ then they can have it but it comes at the price of the potential destruction of their theory for other reasons.
Science is a persons thought bubble bought to life as a theory, measurement is then needed to prove the hypothesis. AGW science has not done this and is not believed. Oddly at this time in history, nuclear physics, quantum mechanics and the universal standard model are all having measurement problems. After billions of dollars worth of really big measuring equipment, the Higg’s boson is more elusive than the scarlet pimpernal. 96% of the universe is missing so we have dark matter that did not work so they added dark energy of a cold kind that cannot be seen.
Dark matter seems to be missing and as of last week dark energy needs to be of a hot kind to make the universe work. This is the same nonsense science as Trenberths missing heat.
These scientists are measuring themselves out of a theory. Go Cern.
The time is rapidly approaching that science needs to take a deep breathe and declare all bets off. I can hope that a new beginning a rennaisance is about to befall the scientific world and a year one declared.
The oceans are now measurable with our wonderful technology, temperature , tides and currents let us start doing it right. The sun the planets and our moon, an ever varying dance of distance gravity and electric connections all measurable. Then over time we can tie it all together to get a reasonable facimile of what the future may hold for us.
Mr Trenberth Sir, It has diddly squat to do with CO2 or missing any thing.
Savethesharks accuses R Gates of having a “pathological inability to assimilate the truth” – which is a seriously unpleasant remark to make in my view – when what he really has is a different perspective, something we should appreciate, because it’s from the collision of different perspectives and opinions that we can keep improving our understanding and keep strengthening our own arguments, by removing our errors when someone else points them out.
Only those who know everything can afford to ignore and/or condemn differing views. And attacking the individual who disagrees with us instead of his argument is never helpful, never reasonable.
The honest scientist/disputant should be keen to have those of an opposing view look at his work in order to test its validity and strength. More dissenting views on here would be a good thing in my view.
Sceptics should be the first to appreciate those who are sceptical of their views.
I agree with Jim Hogg. R. Gates does all of us skeptics a favor by providing thoughtful comments from a different perspective. Without him, WUWT would sound more like an echo chamber, and less like the marketplace of ideas and open-mindedness that attracted me to the site.
One thing that I have really noticed this year is how much cold water appears in a hurricane’s wake in the Atlantic ocean and how much cooler the Gulf of Mexico is. Looking at the most recent NOAA SST anomaly map (9/19/2011), you still a little bit of blue, which is a negative anomaly, where Hurricane Irene went. And you see a lot of blue where Hurricane Katia and Tropical Storm Maria (which did become a minimal hurricane). At the bottom of the Gulf of Mexico there is also a lot of blue from Tropical Storm Nate.
I find all that interesting. I also find it encouraging, especially because I live in a hurricane prone area. Any Cape Verde storm will have to pass over that cold blob of water or over Cuba. Either way, that should prevent any really strong hurricanes from affecting the US. If it takes a route over Cuba into the Gulf of Mexico, there isn’t a lot of heat there for rapid intensification. Of course, the rain will still be an issue.
commieBob says: September 18, 2011 at 6:31 pm
“Someone else observed that the contortions the warmists do to try to fit everything to their CO2 theory are a lot like the contortions necessary to explain the motion of the heavenly bodies with the Earth as the center of the universe.”
Worse than that actually. You could navigate using tables constructed using cycles and epicycles. And you’d get to where you were going. Until the early 17th Century when Kepler published his laws of motion, you could not use heliocentric theories of the universe to predict where Saturn or Jupiter could be found in the night sky and therefore figure out in what direction Piraeus or Alexandria might lie.
I’m quite skeptical that current GCMs have anywhere near the predictive power that the Ptolemaic system had –and as we now know, it was based on a world model that was dead wrong
“HOW LONG UNTIL THE MODELS ARE SAID TO HAVE FAILED?”
In my opinion, it does not matter what any one says today since when that time comes, and if the temperatures have not gone up, the goal posts will be changed. A few years ago, it would have seemed odd if 10 years went by with no warming. When that happened, we were told that with a huge number of model runs, there is a 1 in 8 chance of no warming for 10 years. Then someone said if no warming occurs for 15 years, the theory is wrong. However that is in “danger” happening soon. So someone raised that to 17 years. Trenberth’s latest paper has this sentence:
“The recent work suggests that 20 years or longer is needed to begin to resolve a significant global warming signal in the context of natural variations.”
The global warming is again revealed as regional warming. What’s with that?
Dave says:
September 19, 2011 at 5:56 am
“I agree with Jim Hogg. R. Gates does all of us skeptics a favor by providing thoughtful comments from a different perspective.”
I agree with Jim too. Especially since it seems Mr. Gates is sloooowly becoming more and more a sceptic…..
It is like studying theology….; The more you study, the more sceptical to the dogma you become….
Bob Tisdale says:
September 19, 2011 at 12:48 am
R. Gates says: “Think, for example, about the incredible amount of energy being brought down into the deepest parts of the Atlantic as the gulf stream plundges downward in the N. Atlantic.”
Check a map of North Atlantic surface currents and the locations of THC downwelling points. The downwelling points should be north of the Gulf Stream. Also, in order for the surface waters to downwell as part of THC don’t they have to be more dense than the waters at depth?
————————————-
good point. Is there a place where we can get the data that shows the downwelling is only because of the surface water cooling or the ( surface water cooling + increase in salt content of the surface water owing to evaporation )?
Well Bob, I think your fig-8 tells the story. Anyone who claimed that the plotted data followed a straight line; ANY straight line, would get failed out of my freshman Physics class; (math class too).
But the data themselves; or itself as the case may be, is interesting as always in your posts. And the 13 month running average shows that you can discard a lot of real data, and replace it with manufactured data; but you have to get much more heavy handed to disguise what is happening; and almost no amount of averaging will get you to a straight line. It would be better to simply average ALL of the real data, and report a single average number for the ocean heat content.
R. Gates says:
September 18, 2011 at 6:38 pm
How can some of them be useful? Because they can point to the dynamics underlying the system, even if they can’t forecast exactly how that system will change over time. So in terms of models giving the trends of ocean heat content, the better ones (i.e. still wrong, but still useful) will be best at showing what dynamics are involved in rasing or lowering ocean heat content. A useful model will be refined over and over again. Always destined to be wrong (i.e. not an exact map of reality), but ever closer to hinting at the underlyimg dynamics.
The only underlying dynamics emerging from models to enlighten the clueless will be the ones with which they were programmed.
Bob,
I have a couple questions:
1) Why 0-700 m?
I must have read the rationale for this sometime, I would hope, but I sure don’t remember.
2) ARGO measures 0 – 2000m per http://www-hrx.ucsd.edu/www-argo/
Are there enough ARGO data from 700m-2000m to compare against that?
knmi.nl doesn’t seem to have it.
If you want to see where the Arctic ocean is sinking right now (the time of the year of the warmest SSTs), it will be the areas which are closest to White in this animation of the last 30 days SSTs when viewed from the North Pole. I don’t really see a Gulf Stream anywhere near those white areas R. Gates.
http://www7320.nrlssc.navy.mil/GLBhycom1-12/navo/arcticsst_nowcast_anim30d.gif
On March 8, 2011, at the time of the coldest SSTs of the year, it will still be the nearest to white areas here.
http://www7320.nrlssc.navy.mil/GLBhycom1-12/navo/arcticsst/nowcast/sst2011031118_2011030800_909_arcticsst.001.gif
Bob Tisdale says:
September 19, 2011 at 12:48 am
R. Gates says: “Think, for example, about the incredible amount of energy being brought down into the deepest parts of the Atlantic as the gulf stream plundges downward in the N. Atlantic.”
Check a map of North Atlantic surface currents and the locations of THC downwelling points. The downwelling points should be north of the Gulf Stream. Also, in order for the surface waters to downwell as part of THC don’t they have to be more dense than the waters at depth?
______
It is as a result of the Gulf Stream bringing so much warm and highly salty water northward that the downwelling occurs. I believe it is as a result of the rigth combination of cool water with the salty water mix that forces the water down, and it would be at just the right spot where the density of the salty water and cool water mix. I would love to hear from someone who is truly an expert on the THC to comment here, but it would seem that an huge amount of energy is being diverted downward as a result of the salty warm gulf stream mixing with the cold waters of the far north Atlantic. If there aren’t any THC experts here, perhaps its one more topic I’m going to need to delve deeply into… 🙂
R. Gates: Regarding your September 19, 2011 at 11:54 am reply, wouldn’t it have been easier to simply admit your original comment about THC that “the gulf stream plundges downward in the N. Atlantic” was wrong? Why argue? Also keep in mind that all of that warm water being transported northward by the Gulf Stream does not wind up being downwelled as part of THC. The Gulf Stream is the western boundary current portion of the North Atlantic gyre, so much of it is eventually transported south again by the Canary Current.
Regards
Bob, can I ask you or anyone has corrected for the specific heat capacity of water they are monitoring?
The heat capacity of brine is rather complex:-
http://www.ocean.washington.edu/courses/oc400/Lecture_Notes/CHPT3.pdf
i don’t really see how on can calculate heat in the oceans, with knowing what the salinity is. As as page 19 shows, surface salinity is very different at different places.
Ric Werme says: “Why 0-700 m? I must have read the rationale for this sometime, I would hope, but I sure don’t remember.”
I don’t believe I’ve ever seen the reason for 700m identified, either, but let’s look at the history. The early OHC papers typically reported OHC at multiple depth ranges. In Levitus et al (2000)…
http://www.sciencemag.org/cgi/content/full/287/5461/2225?ijkey=iQleyh4iuzEr.&keytype=ref&siteid=sci
…they noted that most of the variability occurred between 300m and 1000m, with the exception being the North Atlantic, which had significant increases below 1000m.
In 2005, Levitus et al had again reported multiple depths: 0-300m, 0-700m, and 0-3000m.
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat05.pdf
But the 0-3000m depths were reported as a 5-year mean. My assumption is that there were too few observations for them to report the 0-3000m data on an annual basis. They also noted that most of the variability occurred in the 0-700m range.
Sometime between 2005 and 2008/09, the NODC and the other OHC researchers (Ishii and Kimoto, Domingues et al, Wijjfels et al, etc) elected to standardize on 0-700m.
You asked, “ARGO measures 0 – 2000m per http://www-hrx.ucsd.edu/www-argo/ Are there enough ARGO data from 700m-2000m to compare against that? knmi.nl doesn’t seem to have it.”
The only place I know of for ARGO data is the ARGO website. They have special software for dealing with it there as well.
DocMartyn says: “Bob, can I ask you or anyone has corrected for the specific heat capacity of water they are monitoring?”
I simply present the data that has been provided by others. I don’t make corrections. It is my understanding, though, that there are salinity observations included in the OHC data calculations.
George E. Smith says: “Well Bob, I think your fig-8 tells the story. Anyone who claimed that the plotted data followed a straight line; ANY straight line, would get failed out of my freshman Physics class; (math class too).”
The linear trends are determined through regression analyses performed by EXCEL.
nandhee jothijothi85 says: “good point. Is there a place where we can get the data that shows the downwelling is only because of the surface water cooling or the ( surface water cooling + increase in salt content of the surface water owing to evaporation )?”
Sorry. I have spent little time studying THC. Hopefully, someone else reading your question will provide some links.