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

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

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 OHC Update. Bookmark the permalink.

18 Responses to April to June 2011 NODC Ocean Heat Content Anomalies (0-700Meters) Update and Comments

  1. Roger Knights says:

    “especially when one considers the magnitude of the rise that took place during the 1980s and 1990s.”

    But the chart below the quote shows a rise in the 1970s, and no rise in the 1980s.

  2. Bob Tisdale says:

    Roger Knights says: “But the chart below the quote shows a rise in the 1970s, and no rise in the 1980s.”

    The trend is positive during the 1980s, but the discussion would be clearer if I were to use the years of 1983 through 2003. Thanks. I’ll update that.

  3. jmrsudbury says:

    The variance in Figure 4 seems to be decreasing. The peaks are decreasing and the valleys are increasing. Could this be an instrument effect? — John M Reynolds

  4. Bob Tisdale says:

    jmrsudbury says: “The variance in Figure 4 seems to be decreasing. The peaks are decreasing and the valleys are increasing. Could this be an instrument effect?”

    The NODC’s October 2010 corrections changed the seasonal variability and created the significant dip and rebound in late 2004 through 2005, which is. by the way, what keeps the trend from being negative after 2004:
    http://i56.tinypic.com/ay95w0.jpg

    Refer to the NODC’s desciption of the changes here:
    ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/PDF/heat_content_differences.pdf

  5. Philip Bradley says:

    ‘Due to the noise in the Ocean Heat Content anomaly data for some of the ocean basins’

    Bob, I realize the noise claim isn’t yours, but it needs closer scrutiny.

    Noise by definition is an unwanted signal. Given the monthly data is composed of a large number of individual measurements, it can’t be equipment or sampling noise.

    It has to be a real ocean heat content signal, and means the oceans are gaining and losing heat at a much faster rate (on a monthly and shorter scale) than the supposed gain from AGHGs and other forcings.

    Which, at minimum, would mean natural variation has a several times larger effect on the climate than changes in forcings.

    More likely IMO, it means forcings aren’t the primary driver of climate changes.

  6. Philip Bradley says:

    To clarify, the noise is noise in the global warming signal, It’s not noise in the ocean heat content signal.

    Real Climate had a go at explaining the flattening of OHC in 2006, Suggesting weather, ocean circulation and sampling bias could be the cause.

    http://www.realclimate.org/index.php/archives/2006/08/ocean-heat-content-latest-numbers/

  7. Bob Tisdale says:

    Philip Bradley says: “Noise by definition is an unwanted signal. Given the monthly data is composed of a large number of individual measurements, it can’t be equipment or sampling noise.”

    The early OHC data (prior to the ARGO era) for the ocean basins of the Southern Hemisphere are based on a very limited number of readings that vary in quantity and location.

  8. Bob Tisdale says:

    Philip Bradley: For example, here’s a gif animation that illustrates annual observations for depths of 250 to 500 meters from 1979 to 2004:
    http://i55.tinypic.com/14ikdxs.jpg

    It’s from the following post:
    http://bobtisdale.wordpress.com/2011/03/25/argo-era-nodc-ocean-heat-content-data-0-700-meters-through-december-2010/

  9. Philip Bradley says:

    I was referring to the ARGO data.

    When you have a new measurement system specifically designed to overcome the limitations of previous systems, I’m inclined to trust it.

  10. Bob Tisdale says:

    Philip Bradley says: “I was referring to the ARGO data.”

    I haven’t smoothed the graphs that show only the ARGO-era data, Figures 1 and 4. I’ve only smoothed the data in the long-term graphs.

  11. Philip Bradley says:

    My concern is probably somewhat different to yours.

    The essence of science is predictions derived from theory that if found to be incorrect by measurement disprove the theory.

    The current debate about the missing heat and warming hiatus in the models is really about can the Forcings Model/Theory be adapted to account for the measured (lack of) heat gain in the oceans. What they are trying to do is stretch the window where substantially less warming than predicted is observed.

    You can reduce this to ‘How much and how long before measurements inconsistent with predictions disproves the Forcings theory?’

    The Warming camp claim they have now stretched this window to 10 years.

    My original point was that the claimed noise is in the climate warming signal and not in the OHC signal in the ARGO era. Earlier OHC data probably does have sampling noise and perhaps instrument noise as well.

    At the risk of belabouring the point, when you graph OHC, are you looking for OHC per se, or are you looking for the climate warming signal in the OHC data?

    I’d suggest that if you are comparing OHC with say SSTs, no smoothing is required. If you are looking for a climate warming signal, the Warmists are now saying you need to smooth over 10 or more years.

    Apologies for the length, but the ‘missing ocean heat’ goes to the heart of the Forcings theory and all the predictions derived from it.

  12. Bob Tisdale says:

    Philip Bradley says: “The Warming camp claim they have now stretched this window to 10 years.”

    I believe that’s for Surface Temperature, not ocean heat content.

  13. Philip Bradley says:

    Trenberth’s missing heat, WUWT

    The planet’s deep oceans at times may absorb enough heat to flatten the rate of global warming for periods of as long as a decade even in the midst of longer-term warming, according to a new analysis led by the National Center for Atmospheric Research (NCAR).

    The study, based on computer simulations of global climate, points to ocean layers deeper than 1,000 feet (300 meters) as the main location of the “missing heat” during periods such as the past decade when global air temperatures showed little trend. The findings also suggest that several more intervals like this can be expected over the next century, even as the trend toward overall warming continues.

    “We will see global warming go through hiatus periods in the future,” says NCAR’s Gerald Meehl, lead author of the study. “However, these periods would likely last only about a decade or so, and warming would then resume. This study illustrates one reason why global temperatures do not simply rise in a straight line.”

  14. Bob Tisdale says:

    Philip Bradley: Does Trenberth also predict decade long periods of no rise in OHC from 0-700 meters? No. Also, the model used in Meehl et al is not capable of reproducing the instrument temperature record during the 20th century. It is not able to recreate the multidecadal SST anomaly variations in the North Atlantic and North Pacific. It is not able to recreate ENSO. In other words, it has no basis in reality. Is there any reason it should be expected to project future climate? No.

  15. E.A. says:

    >Does Trenberth also predict decade long periods of no rise in OHC from 0-700 meters? No.

    However, that paper suggests that it might be interesting to look at the trends above 300m versus below 300m…..

  16. Bob Tisdale says:

    E.A. says: “However, that paper suggests that it might be interesting to look at the trends above 300m versus below 300m…..”

    If there was easy-to-use OHC data that was split at 300 meters, we’d have a look, but the readily available NODC OHC data is presented for depths of 0-700 meters, so we won’t. And your comment assumes the model used in Meehl et al (CCSM4 run under the RCP4.5 scenario) has a basis in reality. It does not.

  17. Pingback: CSIRO pseudoscience…or voodooscience | pindanpost

  18. Pingback: Looking For Ideas | Bob Tisdale – Climate Observations

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