July to September 2011 NODC Ocean Heat Content Anomalies (0-700Meters) Update and Comments

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 July to September 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.)

STANDARD NOTE ABOUT THE NORTH ATLANTIC: 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, Indian and Southern Ocean subsets are the only ocean basins with positive linear trends. The Southern Ocean went from a slightly negative trend (-0.011 GJ/m^2 per decade) last quarter to a slightly positive one (+0.073 GJ/m^2 per decade) this quarter.

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 (STANDARD DISCUSSION BEFORE UPDATE)

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 uptick in Global Ocean Heat Content anomalies, the trend of the GISS projection is now 3.5 times higher than the observed trend.

Figure 4

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HOW LONG UNTIL THE MODELS ARE SAID TO HAVE FAILED? (STANDARD DISCUSSION)

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

THE NODC MADE A MINOR CORRECTION TO THE DATA FOR LAST QUARTER

And for those with sharp eyes, yes, the NODC appears to have made a correction to the 2nd quarter (April to June) Global OHC anomaly data. It occurred sometime between its original release and now. Animation 1 compares ARGO-era Global Ocean Heat Content anomaly data taken directly from the NODC website. There, the data is provided in terms of 10^22 Joules. Note how the 2ndquarter Ocean Heat Content anomalies rose from about 9.6*10^22 Joules to about 10.4*10^22 Joules.

ANIMATION 1

GLOBAL

The Global OHC data through June 2011 is shown in Figure 6. Even with the recent correction and uptick in the last two quarters, 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.

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 updates since October to December 2010, the Tropical Pacific has not as of yet rebounded as one would have expected during the 2010/11 and 2011/12 La Niña events. 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 event, and the 2011/12 La Niña so far, have done 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.

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. The recent rise was located in the Southern Hemisphere, primarily in the South Pacific. Refer to Figures 9 and 13. There was also a significant rise in the Arctic Ocean, Figure 15, but it had little impact of the OHC anomalies of the Northern Hemisphere, Figure 8. (Maybe a couple of ARGO floats wandered into the Arctic Ocean for the first time this year with the low seasonal ice cover.)

(8) Northern Hemisphere

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(9) Southern Hemisphere

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(10) North Atlantic (0 to 70N, 80W to 0)

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(11) South Atlantic (0 to 60S, 70W to 20E)

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(12) North Pacific (0 to 65N, 100 to 270E, where 270E=90W)

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(13) South Pacific (0 to 60S, 120E to 290E, where 290E=70W)

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(14) Indian (60S-30N, 20E-120E)

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(15) Arctic Ocean (65 to 90N)

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(16) Southern Ocean (60 to 90S)

MAP ANIMATIONS

Animations 2 and 3 are global maps of Ocean Heat Content anomalies for three month periods. They start in January-March 2010, with the next map covering the period of February-April 2010, etc., in sequence, through to the final quarter of July-September 2011, where they linger for a few extra beats. I’ve used 3-month averages because the data is presented quarterly, but I’ve included maps on a monthly basis in an attempt to smooth out the data for the animation, minimizing the jerkiness of the transitions from quarter to quarter. The contour levels are set at +/- 2.0 GJ/m^2 in Animation 2 and set at +/- 1.5 GJ/m^2 in Animation 3.

The rise in the Ocean Heat Content in the South Pacific appears to be La Niña related. We would normally expect warm water to accumulate in the Western Pacific Warm Pool, east of Indonesia, during a La Niña event, but the warm water appears to be collecting along the South Pacific Convergence Zone (SPCZ) this time, instead of the WPWP.

Animation 2

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Animation 3

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And, yes, the OHC anomalies in the Arctic do appear unusual for the quarter of April-June 2011. Does anyone have any idea what data source provides temperature and salinity measurements at depth under the polar ice cap?

(17) North Pole Stereographic Map

SOURCE

All data used in this post is available through the KNMI Climate Explorer:

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

The OHC data in 10^22 Joules, which was presented in Animation 1, is available through the NODC’s website:

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

ABOUT: Bob Tisdale – Climate Observations

About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
This entry was posted in Model-Data Comparison OHC, Ocean Heat Content Problems, OHC Update. Bookmark the permalink.

9 Responses to July to September 2011 NODC Ocean Heat Content Anomalies (0-700Meters) Update and Comments

  1. Jack Langdon says:

    I enjoy reading your blog because you seem very objective and scientifically solid. I am not nearly as well versed and so I would like to see you put a conclusion section on your posts. You could label it as your personal conclusion if you don’t want to pontificate – but things that may seem obvious to you go over my head, and I would be grateful to have the benefit of your summary.

  2. Bob Tisdale says:

    Jack Langdon, I try to remember to include closing comments or summaries on most of my posts. The exceptions to this are the quarterly OHC and monthly SST updates. I wouldn’t really know how to summarize them. All of the additional information, such as the discussions of the Hansen et al illustrations and the Tamino post, are only included here as an attempt to stifle nonsensical criticisms.

  3. Bob Tisdale says:

    Juraj V. : Thanks. I repaired the end year in the North Atlantic graph.

  4. Joe Lalonde says:

    Bob,
    Would you believe…that ANY model that is averaged out actually changes the climate models shape of the planet into a cylinder?
    This can be recreated by mapping how the averaging actually is applied to the planet.
    Cannot put the averaging numbers back to the original data source as they are totally different to the averaging.
    So, what model does it ACTUALLY recreates?

  5. Pingback: Upper Ocean Heat Content Change By Bob Tisdale | Climate Science: Roger Pielke Sr.

  6. slimething says:

    Bob,
    Is there a reason why the latest OHC adjustment doesn’t correlate at all with SST? Would it be logical to assume if OHC rises it should be seen in SST and the upper 300m as well? The adjustment looks to be quite a step change from the previous.

  7. Bob Tisdale says:

    slimething says: “Would it be logical to assume if OHC rises it should be seen in SST and the upper 300m as well?”

    Assuming the variations are related to ENSO, we would TYPICALLY expect a dip in SST and an increase in OHC (0-700m) during a La Nina, and vice versa for an El Nino. This stands out pretty well in OHC/SST comparisons:
    https://bobtisdale.wordpress.com/2011/05/22/sea-surface-temperature-versus-ocean-heat-content-anomalies/

  8. tallbloke says:

    The OHC is rising but sea levels are falling….

    Hmmmmm?

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