Update And Changes To NODC Ocean Heat Content Data

Guest Post by Bob Tisdale,

As noted in the post October 2010 Update to NODC Ocean Heat Content Data, the National Oceanographic Data Center has updated itsOCEAN HEAT CONTENT (OHC) data. This is the dataset based on the Levitus et al (2009) paper “Global ocean heat content(1955-2008) in light of recent instrumentation problems”, Geophysical Research Letters. Refer to Manuscript

The update to the OHC data also included major changes, which have reduced the long-term rise in OHC. Refer to the gif animation, Figure 1, that shows the global OHC data from their June 2010 update (through March 2010) and from the most recent update and change (though June 2010). The revisions are considerable in many ocean basins. As described in their 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. (Refer to the NOAA FAQ webpage What is an XBT?) Immediately following Figure 1 is a link to a graph that shows the difference between the two global datasets, with the June 2010 update subtracted from the September 2010 update.

http://i56.tinypic.com/2vhsta8.jpg

Figure 1 – Global

Link to Graph of the Difference:

http://i51.tinypic.com/2qi07s0.jpg

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Table 1 shows the OHC linear trends (in Gigajoules/Square Meter per Decade) for the global and hemispheric data and for the individual ocean basin subsets. Also shown are the differences (the data from the September 2010 update MINUS the data from the June 2010 update) and the percent change (difference divided by June 2010 update). Note: the June 2010 update included data through March 2010 and the September update/change included data through June 2010, but Table 1 only compares linear trends for the datasets through March 2010. As shown in Table 1, the linear trend for the Northern Hemisphere OHC data only dropped approximately 2%, while the Southern Hemisphere linear trend dropped about 16%. There was a minor increase in North Pacific trend (4%), while there were considerable drops in the linear trends of the South Atlantic (23%), South Pacific (17%) and the Southern Ocean (32%).

http://i52.tinypic.com/1zx5boi.jpg

Table 1

Figure 2 is the gif animation that shows the Southern Ocean OHC data (South of 60S) before and after the September 2010 changes. Prior to the mid-2000s and the introduction of ARGO buoys, the original data (through March 2010) simply appeared to be the climatology with some data added occasionally when it was available. The updated data seems to emphasize that appearance.

http://i54.tinypic.com/111sabn.jpg

Figure 2 – Southern Ocean

Link to Graph of the Difference:

http://i56.tinypic.com/fuqalc.jpg

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And there is good reason for that appearance. Like Sea Surface Temperature datasets based on buoys and ship sensors, there is very little Southern Hemisphere data, at all depths, prior to the ARGO buoys era. Figures 3 through 6 show the 3-month data distribution maps for January through March of 1955, 1975, 1995 and 2005, at depths of zero meters (surface), 250 meters, 500 meters and 700 meters. South of 60S there was little data even in 2005. The maps are available through the NODC Temperature data distribution figures webpage.

http://i52.tinypic.com/2a8orcp.jpg

Figure 3

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Figure 4

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Figure 5

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Figure 6

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THE IMPACT OF CHANGES ON PAST POSTS ABOUT NATURAL OHC VARIATIONS

The recent changes to the OHC data have not had noticeable effects on the timing of the major variations in data that should be attributable to natural variations. For example: The tropical Pacific OHC data still drops during major El Niño events and partially rebounds during most of the La Niña events that follow, Figure 7. The major upward shifts occur during significant La Niña events, which is the recharge/overcharge mode for the tropical Pacific OHC. This, and the similar impact on other ocean basins, was discussed in the post ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data.

http://i52.tinypic.com/wbqt61.jpg

Figure 7

With the changes to the data, the OHC of the North Pacific north of 20N still drops from the late 1950s to the late 1980s, Figure 8, and then suddenly rises. This increase coincides with a shift in North Pacific sea level pressure. This was discussed in the post North Pacific Ocean Heat Content Shift In The Late 1980s.

http://i55.tinypic.com/v8o60i.jpg

Figure 8

The update/changes caused the OHC for most of the other basins to drop more than the North Atlantic OHC. Refer again to Table 1. This makes the contribution of the North Atlantic OHC to global OHC even greater. And much of the disproportionate rise in North Atlantic OHC is caused by Atlantic Meridional Overturning Circulation (AMOC), sea level pressure, and ENSO, as discussed in North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables. One cell of the gif animation in Figure 9 compares global and North Atlantic OHC. The increase in North Atlantic OHC dwarfs the global rise. The second cell in Figure 9 compares the North Atlantic OHC to the global data with the North Atlantic removed. It assumes the surface area of the North Atlantic is 15% of the global ocean surface area. Note the decrease in the global trends. With the North Atlantic, the global linear trend is 0.72 GJ/square meter per decade and without the North Atlantic, the “global” data linear trend drops to 0.043 GJ/square meter per decade. Also note how sharply the North Atlantic OHC has dropped since 2005. The North Atlantic is a major contributor to the flattening of global data in recent years.

http://i56.tinypic.com/2m2hq1v.jpg

Figure 9

GIF ANIMATIONS — BEFORE AND AFTER CHANGES

Figures 10 through 18 are gif animations that compare the NODC OHC data for the hemispheres and ocean basin subsets before and after the recent changes. I’ve also provided links to graphs of the differences, with the June 2010 data subtracted from the September 2010 data. They are provided without commentary.

http://i53.tinypic.com/aken3m.jpg

Figure 10 – Tropical Pacific

Link to Graph of the Difference:

http://i51.tinypic.com/34fo420.jpg

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http://i51.tinypic.com/2zrks8x.jpg

Figure 11 – Northern Hemisphere

Link to Graph of the Difference:

http://i56.tinypic.com/22xonc.jpg

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http://i52.tinypic.com/2cy5vf5.jpg

Figure 12 – Southern Hemisphere

Link to Graph of the Difference:

http://i53.tinypic.com/2vaim1u.jpg

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http://i52.tinypic.com/r91v7d.jpg

Figure 13 – North Atlantic

Link to Graph of the Difference:

http://i55.tinypic.com/dm9tas.jpg

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http://i55.tinypic.com/2lcwcir.jpg

Figure 14 – South Atlantic

Link to Graph of the Difference:

http://i51.tinypic.com/2akfvaf.jpg

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Figure 15 – Indian Ocean

Link to Graph of the Difference:

http://i56.tinypic.com/2gxfwvq.jpg

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http://i52.tinypic.com/2dtdiyd.jpg

Figure 16 – North Pacific

Link to Graph of the Difference:

http://i56.tinypic.com/nx553a.jpg

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http://i52.tinypic.com/2u4313m.jpg

Figure 17 – South Pacific

Link to Graph of the Difference:

http://i51.tinypic.com/5yz3sw.jpg

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http://i51.tinypic.com/n5lmp1.jpg

Figure 18 – Arctic Ocean

Link to Graph of the Difference:

http://i55.tinypic.com/2d7h387.jpg

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SOURCE

The NODC OHC data is available through the KNMI Climate Explorer:

http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere

(Thanks to Dr Geert Jan van Oldenborgh of KNMI for creating and maintaining Climate Explorer.)

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Fantastic work!…..but..Is this “Climate Disruption” or just another cyclic and natural minimum we are in?. Just to avoid that the then Global Warmers who after became Climate Changers and now they present the phenomenon as “Climate Disruption” could surprise innocent people, which, btw, we are not, here at WUWT, thanks to real, and serious researchers like you.
So we know it: Things are getting colder but it’s Ok, let’s buy more popcorn!

richard verney

Interesting post but it would be good to have a section setting out a summary, conclusions and implications.

Sean

What’s missing in all of this is error bars. According to a paper published in Nature that Josh Willis was a co-author on Lyman), prior to 2003, when the Argo Bouy network was deployed, the error bars on the total ocean heat content are enormous. They tighten up remarkably when you a more uniformly deployed network of Argo bouys. http://www.nature.com/nature/journal/v465/n7296/abs/nature09043.html
So the really good data shows TOC stable for 7 years and the sparser data taken prior to 2003 shows heating. My question is, are there graphs that show how the uncertainty changes with time for the TOC data and have these been updated as well?

Brego

Bob, what effect did these changes have on the linear trend for global OHC since 2003 (when the ARGO network came online)? My eyeball thinks it changed a flat or slightly negative trend and turned it into a positive trend. Is that right?

Splendid work, thankyou!
K.R. Frank

MikeEE

I just remembered, the 60’s were much colder than I thought…

Bob, thanks as always for your exhaustive and comprehensive overview of the data. It’s interesting to see that the big splice jump from XBT to ARGO seems to have been toned down in this latest revision. Interesting also that the general global shape of the ARGO section of the curve seems to agree most closely with Craig Loehle’s take on the data!
http://wattsupwiththat.files.wordpress.com/2009/03/loehle_ocean_heat_content.png?w=510&h=322

TinyCO2

Nice work as usual Bob.
What’s this gonna do to the climate models? And if they’re so good, did they predict that there must be something wrong with the OHC? Or am I being silly because it’s another variable they don’t include?

Typo here?

Figure 9 compares the North Atlantic OHC to the global data with the North Atlantic removed. It assumes the surface area of the North Atlantic is 15% of the global ocean surface area. Note the decrease in the global trends. With the North Atlantic, the global linear trend is 0.72 GJ/square meter per decade and without the North Atlantic, the “global” data linear trend drops to 0.043 GJ/square meter per decade.

My reading of the graph (and handy straight line trend equation) say that 0.72 should be 0.194.
Interesting adjustments nonetheless.

Sean says: “What’s missing in all of this is error bars. ”
The basin times series data through the NODC website…
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html
…is presented with standard errors. Link to the annual global/hemisphere page, for example:
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/DATA/basin/yearly/h22-w0-700m.dat
The data through the KNMI Climate Explorer, which I used for this post, is not provided with error data.

Sean says: “So the really good data shows TOC stable for 7 years…”
There have been numerous corrections to ARGO data ever since the floats were deployed. “Really good” is relative, but they are more numerous.

Rob R

I like the breakdown into oceanic subbasins. This means I can look at changes in sea surface temperatures, changes in ocean heat content, and changes in air temperature at a regional level. For instance in my own region (Western South Island, NZ and using the raw air temp data from the cliflo database) I note there has been minor almost trendless change in local air mean temperature, sea surface temperature, and ocean heat content since the 1950’s. This is about 60 years of minimal change. When is the supposed greenhouse-gas-caused temperature change supposed to hit down here? It is rather late to the party. Should I expect a step change event like the “Great North Pacific Transition” from the mid 1970’s? I suspect I shouldn’t hold my breath over this issue.

mkelly

“…from revised Expendable Bathythermograph (XBT) bias calculations.”
During my 20+ years in the US Navy I must have been involved with hundreds of BT drops from P-3 Orion and S-3 Viking aircraft. We attempted to dropped one per flight. There were P-3 flying all around the world. I would assume these are available if historical data is wanted back to the 1950’s I would guess.

Robinson

On the assumption that oceanic heat is transferred to the atmosphere rather than the other way around, can we presume that this therefore explains almost all 20th century warming?

Stephen Wilde

The 1955 to June 2010 version seems to my eyeballs to show a clearer pattern as follows:
i) A general fall in OHC from 1955 to 1970
ii) a general rise from 1970 to 2000
iii) A plateau and possible beginning of a fall from 2000 to date.
I would just point out that the period of falling OHC was during a period that the jetstreams were more towards the equator, then the rising trend as they moved poleward and now possibly a falling trend once more now that the jets have shifted equatorward again.
That meshes in with the albedo thread here:
http://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/
where it seems that albedo declined from the 80s as the jets moved poleward and started to recover again as the jets moved equatorward again from the late 90s.
I take that as prima facie evidence supporting my proposition that it is the latitudinal position of the global cloud bands that most affects global albedo and the quantity of solar energy entering the oceans.
A poleward shift reduces albedo so OHC rises. An equatorward shift increases albedo and OHC falls.

Stephen Wilde

Whoops, in my previous post 1980 should read 1970.

MartinGAtkins

The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t.

Ric Werme says: “Typo here?”
Yup. Thanks for noting there was a mistake in that sentence, but it’s not the number you’ve noted later in your comment: the way I wrote it was confusing. I’ve changed it with corrections to the following at the co-post at my website:
“The ‘Global’ linear trend (blue curve) is 0.072 GJ/square meter per decade and without the North Atlantic, the ‘Global Minus North Atlantic’ data linear trend (green curve) drops to 0.043 GJ/square meter per decade.”
Thanks again.

Stephen Wilde

Interesting that the Arctic Ocean graph shows a low point and trend change around 1980 whereas the global chart shows a low point and trend change around 1970.
That suggests a ten year lag which approximately matches the period of time from the 1998 super El Nino to the peak summer melt in 2007.

david

The readers of this thread may be interested in a paper by Knox and myself showing that the trend of recent [since 2002] global ocean heat content is negative. Go to .
David Douglass
[reply] David, just type the url and wordpress will make the link live – RTmod

Steve Koch

So OHC has been dropping a bit since late 2004 instead of 2006.
I highly recommend looking at this link (very clear explanation):
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/PDF/heat_content_differences.pdf
These comments from the linked slides are interesting:
• Many CTD/bottle data do not come to NODC within 3 months. Many do not come at all.
• Changes to XBT data are usually replacement of real-time data with full profile delayed-mode data, including delayed-mode quality control.
• Changes to Argo profiles are mostly pressure adjustments applied during delayed-mode quality control.
I guess this means that the Argos sensors have an internal recording capability that has much more information than what is transmitted in quasi realtime. This recorded memory is presumably accessed relatively infrequently. When the recorded data is available, it permits post processing that improves the accuracy of temp records.
I wonder what this means: “mean of five decadal climatologies to remove temporal bias”. Maybe Levitus 2009 explains it.
Bob, did you do a post about the Levitus 2009 paper?

commieBob

I’m not sure what they are measuring here. It would nice if someone could tell us what the temperature change was in the water column.
If I have it correctly, the heat content of the water column changed less than a tenth of one percent over the last sixty years. That would be about 0.3 degrees K. That doesn’t sound like much and it sounds to me like it is well within measurement error.
If someone (more familiar with the physics) would do the math I would be grateful. I also agree with Sean; some error bars would be nice.

commieBob says:
October 18, 2010 at 2:02 pm
If I have it correctly, the heat content of the water column changed less than a tenth of one percent over the last sixty years. That would be about 0.3 degrees K. That doesn’t sound like much and it sounds to me like it is well within measurement error.

The thing to remember is that two metres of ocean has around the same heat capacity as the entire atmosphere above it. So a 0.3K increase in the top 700 metres of ocean is a heck of a lot of additional energy. This additional energy must have come from additional insolation at the surface. This would be a function of a more active sun combined with a concomitant reduction in albedo – less clouds.
This pretty much fits the high average solar output in the second half of the C20th, which was well above the long term average.
There’s your global warming.
If someone (more familiar with the physics) would do the math I would be grateful. I also agree with Sean; some error bars would be nice.
I did the math. Using the rise in sea level due to thermal expansion, the energy gain in the 1993-2003 decade is equivalent to an extra 4W/m^2 – way more than co2 can do. Levitus et al mysteriously reduced the amount of extra energy by a large factor between their 2000 paper and their 2007 paper. I think it’s because they realised there was no way co2 could account for it, even if back radiation from the atmosphere could enter and heat the ocean, which it can’t.

Steve Koch says: “Bob, did you do a post about the Levitus 2009 paper?”
Nope. I’ve just included links to the paper when I’ve posted the data. Regarding “mean of five decadal climatologies to remove temporal bias”, refer to their paragraph 12 (page 3):
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf

Bob,
what unit is GJ* m**-2?
Have you (or Climate Explorer) divided the OHC by the ocean area?

Morris Minor

Thanks Bob,
Could you please explain to me what the unit GJ/m2 means. I assume this is the energy in a column of water with surface area 1m2… but what depth is the column?
I also assume the energy value is calculated from a temperature measurement.. is that correct? Thanks for the excellent work..

Dr T G Watkins

I agree with Richard Verney, a summary and commentary would be helpful for us simpletons (relatively).I always feel a bit stupid after reading Bob’s posts and I have followed links. I can understand why Bob presents the evidence (data) but refuses to be become embroiled in commentary but a little help from some of you clever guys would be appreciated.

commieBob says: “It would nice if someone could tell us what the temperature change was in the water column.”
In an earlier paper, Levitus et al (2005), they provide the rises in ocean temperature for 0-700 meters based on linear trends in their Table T1 as 0.118 deg C from 1955 to 2003. See page 17:
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat05.pdf

Morris Minor says: “Could you please explain to me what the unit GJ/m2 means. I assume this is the energy in a column of water with surface area 1m2… but what depth is the column?”
Sorry that I didn’t note the depths as 0-700 meters in the post but they are included in many of the graphs. And yes, the GJ/m^2 is gigajoules (1 billion joules) per square meter.

Paolo M. says: “what unit is GJ* m**-2?”
Gigajoules per square meter.
You asked, “Have you (or Climate Explorer) divided the OHC by the ocean area?”
I did the dividing based on coordinates of ocean basins. The KNMI Climate Explorer allows users to download data based on global coordinates. And they present the data in a fomat that would work on that basis and that is Gigajoules per square meter.

Change Is Universal

Bob,
I’m a fan of your posts because they contain lots of figures. Is it possible to compare OHC at different depths. For example, 50m intervals for the tropical Pacific. Would be nice even if we can only use Argo data…
Cheers.

Excellent analysis, Bob.
It’s heartening to see adjustments go in the other direction now and again. Will this mean a re-evaluation by HadISST?

bob

Hmmm, I wonder what the ratio of mass of CO2 molecules in the atmosphere is to the mass of water is the oceans. I mean, I’m just wondering. It’s really quite amazing that the reemission of photons from CO2 could warm the atmosphere, which, in turn warms the oceans (in such a short period of time). I guess I wasn’t paying close enough attention in my heat transfer classes when they covered that. Boy, those must be some really energetic photons. Oh wait, no I have that wrong. It must be all about the “positive feedbacks” — you know, perpetual motion, cold fusion, that sort of thing.

Stephen Wilde wrote, “I take that as prima facie evidence supporting my proposition that it is the latitudinal position of the global cloud bands that most affects global albedo and the quantity of solar energy entering the oceans.”
Latitudinal position of the clouds would make no difference if the net downward shortwave radiation at the surface remained constant. Do you have data to support your conjecture either way?

richcar 1225

How do the warmists explain the fact that the North Atlantic is accumulating heat at twice the rate of the rest of the world? Does the difference between the two rates represent the so called missing heat?

EthicallyCivil

So if the values have been correct downward, does that mean that there is more missing ocean heat than was thought prior? How much worse does this make the “missing heat” look?

Bob Tisdale says: October 17, 2010 at 7:06 pm
vukcevic: Have I missed something on another thread? I’ve searched but couldn’t find any data or a description. What is the North Atlantic Precursor? What’s the source data and how do I duplicate the NAP data in this graph?
http://www.vukcevic.talktalk.net/CET-NAP.htm
Why does it only impact the North Atlantic and Central England Temperatures?

Hi Bob,
I looked into SSN, magnetic fields etc, but as you know ‘correlation is no causation’ is a big problem. Finally, I think I found a physical process which could give the answer.
There is a similar process going on in the North Pacific, but data is not going as far back, working title for that one is ‘PDO generator’, not exactly appropriate, but will do.
http://www.vukcevic.talktalk.net/PDOc.htm
Why no details? See my post here

Dr T G Watkins says: “I can understand why Bob presents the evidence (data) but refuses to be become embroiled in commentary but a little help from some of you clever guys would be appreciated.”
Depending on the post, I do provide detailed commentary. And I’m happy to answer questions about topics I fail to cover in enough detail.

This is interesting information. My biggest curiosity isn’t the actual change in the values. The tiniest changes to measured temperatures will translate to changes in energy when large columns of water are involved.
The ENSO cycle trigger very large changes in energy, but what powers those changes. Understanding the driving factor of the ocean oscillation would be very helpful. I have often wondered about how much energy is dissipated by an EL Nino. The energy transferred around evaporation and the warming of the atmosphere is significant.
So much energy is on the move that the atmosphere is still warm almost a year later. These events are very interesting.
John Kehr
The Inconvenient Skeptic

paulhan says: “Will this mean a re-evaluation by HadISST?”
The Hadley Centre is re-evaluating SST data for a replacement for HADSST2, and it would be called HADSST3. I think it was held up, though. I don’t know if that will have any impact of HADISST, which is a totally different beast and the best of the long-term datasets as far as I’m concerned.

Scott Covert

Thanks for the head exploding amount of data Bob!
I’m going to have to read this three times to get the big picture.
Thanks for the hard work.

Neville

I can only agree that Bob allows we slower members a chance to read and understand more info as it becomes available, BUT I wish a short summary and conclusion was part of the package.
Perhaps Tall bloke or some one else could do the honours?

Change Is Universal says: “Is it possible to compare OHC at different depths. For example, 50m intervals for the tropical Pacific. Would be nice even if we can only use Argo data…”
That’s a tremendous amount of data to sort through, even with the depth intervals provided by the NODC. I doubt very much that NOAA will ever present it that way through their NOMADS system for that reason.
For the ARGO data, there is software that allows users to sort through their data, but I haven’t looked into it. Also, it’s my understanding that the ARGO data they provide has not been corrected, and they’ve also stopped updating it, last update was sometime this summer. Refer to the “Global Marine Argo Atlas” webpage:
http://www.argo.ucsd.edu/Marine_Atlas.html

vukcevic: Some day you’ll link the source of your North Atlantic Precursor and ‘PDO generator’, but based on your linked comment, it doesn’t look like it will be soon.

Bob …..?????
Any direct involvement in the work of the Pielke’s Family.
(april >>>>september)
thanks.

david

Here is the URL to the Knox/Douglass paper
http://www.pas.rochester.edu/~douglass/papers/KD_InPress_final.pdf
David Douglass

Brego says: “Bob, what effect did these changes have on the linear trend for global OHC since 2003 (when the ARGO network came online)? My eyeball thinks it changed a flat or slightly negative trend and turned it into a positive trend. Is that right?”
Yup, the dip in 2004 helps the postive trend. Let me see if I can dig up the old yearly data through 2009 and compare it to the present data.

vukcevic says:
October 18, 2010 at 3:09 pm
Remarkable your new graph. Hope you will reveal the driver.

George E. Smith

“”” Paolo M. says:
October 18, 2010 at 2:23 pm
Bob,
what unit is GJ* m**-2? Paolo; no mystery; the unit is GigaJoules per square metre; as in G, standard prefic for 10^9, J standard symbol for Joules (energy), and m standard unit for Metre (length), so it is energy per unit area.
rather simple actually.

Brego: As a follow up, the following graph shows the short-term OHC trends (2003 to 2008 for original paper and 2003 to 2009 for the Jan 2010 and Sept 2010 corrections.) The dip in 2004 increases the trend a little in the most recent update, but it still is far less than the trend in the original paper:
http://i51.tinypic.com/oj3wac.jpg