Well, there seems to be an odd shift in the OHC data circa 2002:

http://climatesci.org/wp-content/uploads/global...

Also evident in Bob Tisdale's post. Whatever it is that happened, it can't be an AGW induced acceleration, since it constitutes a sudden shift. You'll notice that apart from that sudden change, there is no sign of "acceleration" in the data, and the shift may well be in the process of disappearing:

http://i34.tinypic.com/dev5ld.png

H/T to Bob for that one!

Yes, it will be interesting to run some break tests on it. Wong has made some strong claims about 'significance' of the trend since 1998 and and OHC increasing faster. She is a lawyer so she should know the difference between making statements that stand up in court, and manipulative speculations.

I'd view Bob's plots with caution. As he says, they're not based on posted NODC plots, but on a KNMI report. I looked at the underlying tables, and there are a lot of missing values. I suspect NODC is waiting for more data to come in before posting.

It seems the OHC data set should be viewed with caution. Its short, heterogeneous, with many biases and adjustments. All the more reason to be concerned with categorical statements made about it.

Nick Stokes: You wrote, "As he says, they're not based on posted NODC plots, but on a KNMI report."

Incorrect. You've misinterpreted what I've written. They are based on the posted and updated NODC data that KNMI downloaded from NODC.

You wrote, "I looked at the underlying tables, and there are a lot of missing values."

Two questions: Are you looking at the 2009 data? And when you note missing data, what are the coordinates of the missing data?

You wrote, "I suspect NODC is waiting for more data to come in before posting."

The data has been posted by the NODC. I provided a link to the raw NODC data and before that link, I wrote, But the single 22.4 MB dataset at the top of the table does contain the January through March and the April through June data, which were updated (added) on September 14, 2009:
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/DATA/heat_3month/HC_0-700-3month.tar.gz
Can't get much plainer than that.

Bob,
It isn't incorrect. I carefully said "posted NODC plots", and there are no new ones. Of course there is posted data - that's where I noted all the 999's. I'm not familiar with the format, and and didn't make a detailed analysis. But I think there is likely to be a reason why NODC has not posted plots yet, and so I suggest caution.

Nick Stokes: You wrote, "Of course there is posted data - that's where I noted all the 999's. I'm not familiar with the format, and and didn't make a detailed analysis. But I think there is likely to be a reason why NODC has not posted plots yet, and so I suggest caution."

Read the Instructions, Nick. Here's a link:
http://www.nodc.noaa.gov/OC5/WOA05/readwoa5.html

Scroll down and you'll find the following illustration, which is one of the NODC’s Coordinate Systems for Statistical Fields:
http://i38.tinypic.com/103s7s8.png

The illustration looks pretty straight forward. So if you’re looking at 1-degree data, the first Field would have the global coordinates of 90S, 1E. Or if you’re looking at the 5-degree data, the first Field would have the global coordinates of 90S-85S, 0-5E. Those should be right in the center of Antarctica and they are represented by -999.999.

Now, with a quick check (less than 1 minute) you could open a data file in Word or Notepad and determine that there a 64,800 Fields in the HC_0-700_A9A0406.dat File and of those 64,800 Fields, 23,380 or 36% of them are represented by -999.999. Do the same thing for the first 1955 data file and you’ll find the same number of Fields (64,800) and approximately the same number of fields with -999.999. (It wouldn’t be much of an Ocean Heat Content dataset if they were missing 36% of the data in approximately the same areas for the entire period.) Land mass represents approximately 31% of the global surface area. Do we assume the other 5% might be sea ice?

Feel free to continue to use caution, Nick, if you still think it’s necessary. I’ll continue to plot the data and post about it.

Have a nice day.

Nick Stokes: My apologies. Your suggestion of caution turned out to be correct. The NODC updated their OHC data today.
http://bobtisdale.blogspot.com/2009/10/nodcs-co...

No worries. I'm generally a doubter about OHC data. I wish it was better.

Sen Wong seems to have relied on the 2009 Synthesis Report, Figure 8 for her notion of acceleration of OHC;

http://climatecongress.ku.dk/pdf/synthesisreport/

I'm not sure where the good Sen gets her evidence for sea-level but the notion of accelerating rises in sea-level seems to have taken a hit from this paper;

http://www.ocean-sci-discuss.net/6/31/2009/osd-...

Silly me; Figure 1 from the same link to the Synthesis Report is the Sen's justification for sea-level.

The OHC in the graph you show has accelerated: It starts out with a slightly negative trend, followed by a positive trend. I dont see any reason to look specifically at "since 1998".

Some other OHC estimates can be seen here:
http://www.realclimate.org/index.php/archives/2...
Ishii and Levitus have also since revised their estimates to account for the problem described in the RC post. I personally like their estimates better, because they are independent of the topex/poseidon altimetry data. Afaik Domingues uses "optimal" interpolation, with the EOFs determined from the altimetry data set.

Aslak, thanks for the references, much appreciated. I was actually wondering if in fact the 'acceleration' is significant, given the short period and high autocorrelation. I haven't had time to do the analysis yet.

Increasingly it is apparent that the OHC is not an indice of AGW;

http://wattsupwiththat.com/2009/08/11/ocean-hea...

One of the outstanding issues of the NOAA/Levitus record is this;

http://wattsupwiththat.com/2009/06/02/anomalous...

That transition spike, if excluded, in combination with the recent further decrease in OHC has taken OHC almost back to where it started in the 50's.

Here's my initial reaction:

http://devoidofnulls.wordpress.com/2009/10/18/a...

My impression is that the Ocean Heat Content data unsurprisingly shows that same spurious acceleration effect I discussed with you earlier (namely, the curve changes sign of rate of change suddenly, without much change in the rate before or after.) Needless to say, I don't regard the claims of accelerating OHC rise as very impressive.

I would also appreciate it if anyone can find any errors I made in my analysis. For instance, can anyone else verify the very large slopes I seem to be getting?

IMHO these analyses need the CI's to show the probability the rate exceeds the expected rate. Not sure if there is enough data though.

I might try and get to that, but I also expect that the data is too sparse to get any good (that is, statistically "robust" in the sense that they are fairly firm-not "good" in the "I like them" kind of way) answers.