I’ve moved to WordPress: http://bobtisdale.wordpress.com/

Wednesday, May 13, 2009

Levitus et al (2009) Ocean Heat Content – Comparison of The Ocean Basin Data

I’ve moved to WordPress.  This post can now be found at Levitus et al (2009) Ocean Heat Content – Comparison of The Ocean Basin Data
###################
INTRODUCTION

In my post The Latest Revisions to Ocean Heat Content Data, I provided comparisons of the recent Levitus et al (2009) Ocean Heat Content (OHC) data to other recently released reconstructions. This post compares ocean basin data from the Levitus et al (2009). The OHC data are available through the NOAA National Oceanographic Data Center here:
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/index.html
There is also a link to the Levitus et al (2009) paper on the webpage:
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf

COMPARSION CHART OF OHC BY BASIN

Figure 1 is a comparison chart of the OHC for the Atlantic, Indian, and Pacific Ocean basins. This presentation does not consider the differences in the areas of the three oceans. The Pacific Ocean has more than twice the surface area of the Indian Ocean and ~60% more surface area than the Atlantic Ocean. Regardless of area, the Atlantic Ocean Heat Content rose more than the OHC of the Indian and Pacific Oceans.
http://i41.tinypic.com/dmvbxj.jpg
Figure 1

AREA-ADJUSTED COMPARISON CHART

Figure 2 shows the area-adjusted OHC for the individual oceans, where the data is in terms of OHC/million sq km. The surface areas of the oceans used in Levitus et (2009) were not listed, so it’s impossible to determine if the Arctic and Southern were included in the data of the three major oceans, or if the Gulf of Mexico, Mediterranean Sea and Caribbean Sea were included in the Atlantic data. So I used the standard ocean surface areas listed in Wikipedia, but excluded the “seas” from the Atlantic: 82.4 million sq km for the Atlantic, 73.5 million sq km for the Indian, and 169.2 million sq km for the Pacific. The Atlantic Ocean heat Content has had the largest increase over the term of the data.
http://i40.tinypic.com/nxlsh4.jpg
Figure 2

Adding linear trends to the area-adjusted data, Figure 3, shows that Indian and Pacific Oceans trends were fundamentally the same. It also shows that the Atlantic Ocean Heat Content rose at a rate that was more than twice that of the Indian and Pacific Oceans.
http://i40.tinypic.com/23rpmc7.jpg
Figure 3

COMPARISONS OF SST ANOMALIES AND SSTs

The rise in the area-adjusted OHC for the Atlantic was unexpected, since the rise in the SST anomalies of the Indian Ocean exceeded the Atlantic and Pacific Oceans. Refer to Figure 4.
http://i44.tinypic.com/724p5e.jpg
Figure 4

And for those wondering about actual SSTs, Figure 5 is a comparison of Atlantic, Indian, and Pacific Ocean SSTs (not anomalies). The SST of the Atlantic Ocean is ~2.5 deg C lower than the Indian and Pacific Oceans.
http://i42.tinypic.com/24c5uh1.jpg
Figure 5

NORTH AND SOUTH ATLANTIC OHC

Curious about the rise in the OHC of the Atlantic, I plotted the North and South Atlantic OHC data, Figure 6. The rise in the North Atlantic OHC was obviously greater than in the South Atlantic.
http://i39.tinypic.com/v5ebzp.jpg
Figure 6

Again, I do not know if the Levitus et al included the Gulf of Mexico, Mediterranean Sea and Caribbean Sea in the North Atlantic data. But in Figure 7, I assumed they were excluded. I also assumed the area of the Atlantic Ocean without the additional seas (82.4 million sq km) was evenly split between the hemispheres. The rise in the area-adjusted OHC of the North Atlantic is more than twice that of the South Atlantic. And note that the linear trend of the South Atlantic is approximately twice that of the Pacific and Indian Oceans, Figure 3.
http://i41.tinypic.com/2yzfv2r.jpg
Figure 7

Why did the increase in area-adjusted Atlantic Ocean OHC more than double the rise of the Indian and Pacific Oceans? This can also be seen in the “Heat Storage Per Unit Area” values presented by Levitus et al in their Table T1. Refer to Figure 8.


If the answer lies with Atlantic Meridional Overturning Circulation, then the use of only the top 700 meters for OHC might be misleading.
http://i44.tinypic.com/pc7b9.jpg
Figure 8

8 comments:

Amber said...

Bob,
Here is something to look at,
the pacific ocean is contracting and the Atlantic is expanding.

is there a way to graft in the rates for both? do the rates change in 100year terms?
there has to be a way to know about the under water volcanic activity.
Thanks man
P.S. it looks like I am signed in as my wife! lol
Tim L

Bob Tisdale said...

Tim L: You wrote, “the pacific ocean is contracting and the Atlantic is expanding. is there a way to graft in the rates for both? do the rates change in 100year terms?”

I’m not sure what the first sentence means. The sea levels of both the Atlantic and Pacific Oceans have increased. Refer to my post on sea levels of the Atlantic, Indian, and Pacific Oceans:
http://bobtisdale.blogspot.com/2008/12/sea-level-data-global-and-indian.html

What I can graph is based on data availability. I haven’t run across any long-term (100 years) ocean heat content or sea level data.

You wrote, “there has to be a way to know about the under water volcanic activity.”

I haven’t run across anything of value to you. Everything I’ve read points to minimal impact on SST and OHC. Have you found any scientific papers that describe any significant volcanic heat input to the oceans?

Amber said...

Sorry, brain not engaged!
What I meant to say was, -the floor of- the pacific ocean is contracting (subduction) and the Atlantic is expanding(upwelling). Even if the rate of change was 1cm different per decade it would be very large change in infilling of the floor, this infilling is hot molten material, IE added heat content. I find it difficult to believe that there could be a liner movement over 100K years,
there must be fast advances and slower non movement times.
This might also explain start/stop of the ocean conveyor. and warm/ice periods.
all of this is speculation, and I will keep an eye out for these related items.
Tim Lint

Have you found any scientific papers that describe any significant volcanic heat input to the oceans?

Uh, well, this is what I am working on, because no one (models) will consider this, a hot heated floor as a variable in heat content and must be included.

if the Atlantic changes in size, what are the effects? this sounds like a doctorate theses...lmao

Anonymous said...

Hi Bob, I notice that your graphs have different start points. I would have thought that they should all start at a zero point for comparison. This makes me presume there is more of the chart that has been snipped prior to posting. It would also be interesting to see charts comparing OHC with temp, CO2 and sunspot. Thank you for your work.
Regards Frank Hunt

Bob Tisdale said...

Frank Hunt: You wrote, "Hi Bob, I notice that your graphs have different start points. I would have thought that they should all start at a zero point for comparison. This makes me presume there is more of the chart that has been snipped prior to posting."

No reason to presume that I'm snipping data. I simply plot the raw data that they provide. Click on the links. Open the data files. You'll see that what I've plotted is where they start. The only adjustments I made in this post were to Figures 2 and 3, and, in those, I divided the raw annual OHC data by the area of the individual oceans in millions of km^2 that are shown in parenthesis.

Regarding the comparisons to temp, sunspots, CO2, I have no plans to do any other posts on the Levitus OHC data.

gotodo said...

Thanks for offering the link to OHC data!!

Steve Koch said...

Bob,

If the OHC trend in the Pacific and Atlantic continues, do you expect A and P ocean levels will eventually stop rising? Are there any functions that take OHC history as an input and produce a projected ocean level as an output?

Bob Tisdale said...

Steve Koch: You asked, "If the OHC trend in the Pacific and Atlantic continues, do you expect A and P ocean levels will eventually stop rising?"

Steve, first, this is a old version of the NODC (Levitus) OHC data. They've updated it and revised it a few times. The most recent change was to the 2006 to 2009 data, and it's much flatter now. Refer to:
http://bobtisdale.blogspot.com/2010/02/ohc-linear-trends-and-recent-update-of.html

To answer your question, there are a number of components of sea level. Thermosteric (temperature related) sea level should also have flattened in recent years. The continued rise in OHC should therefore be from the contribution of mass due to glacial run-off.

With respect to your second question, I have seen no studies that try to project sea level from OHC trends.

Donations

Tips are now being accepted.

Comment Policy, SST Posts, and Notes

Comments that are political in nature or that have nothing to do with the post will be deleted.
####
The Smith and Reynolds SST Posts DOES NOT LIST ALL SST POSTS. I stopped using ERSST.v2 data for SST when NOAA deleted it from NOMADS early in 2009.

Please use the search feature in the upper left-hand corner of the page for posts on specific subjects.
####
NOTE: I’ve discovered that some of the links to older posts provide blank pages. While it’s possible to access that post by scrolling through the history, that’s time consuming. There’s a quick fix for the problem, so if you run into an absent post, please advise me. Thanks.
####
If you use the graphs, please cite or link to the address of the blog post or this website.