Ocean Heat Content Adjustments: Follow-up and More Missing Heat

Guest post by Craig Loehle

On June 2, 2009 at WUWT in Anomalous Spike in Ocean Heat Content I commented on what looked like a data discontinuity in ocean heat content data. In this follow-up post, I show that the recent update to the OHC data at NOAA adjusts the recent data down, as I suggested nearly 2 years ago (though I doubt I had anything to do with it). The original post is in italics followed by my update plus an update on trends.

In the paper

Levitus S., J. I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, A. V. Mishonov (2009), Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems, Geophys. Res. Lett., 36, L07608, doi:10.1029/2008GL037155

the long term trend of ocean heat content is reanalyzed in Levitus to attempt to correct for bias in instrumentation, and the record is extended. The graph below depicts the result.

The most recent period, from 2003, uses the ARGO profiling floats, whereas earlier periods use a variety of instruments with various biases. Patching all these data together is a challenge. I draw your attention to the strong spike in the red line from 2002 to 2003. This line is the point at which the earlier data is joined up with the ARGO data. The magnitude of the jump is the largest in the entire record. The transition to the ARGO data can not be said to have been accomplished with a long cross-calibration period. It thus looks to me like there may be an error in how the different data sets are stitched together. I in no way am implying malfeasance here. I have discussed this situation with Roger Pielke Sr. and Josh Willis and they agree it looks odd and merits further investigation. Dr. Pielke points out that there is not a comparable jump in the SST data. I think this example illustrates that if there is a big jump in the data right when you change your instrumentation, it is perhaps good to look a little closer.

Below is the change notice ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/PDF/heat_content_differences.pdf

from NOAA showing that the recent data (post-2002) have been adjusted downward based on many QA/QC issues. There is still a large jump in mid-2003 when the Argo float data join the other data in the database. I believe there is still a data continuity/calibration issue here and that recent data need further adjusting down.

There is a famous quote in the Climategate emails from Trenberth about the “travesty” that there is missing heat which we can’t account for. This refers to the fact that the radiation balance as understood and as modeled implies that the Earth should be absorbing radiation and warming up. The observed rate of warming, including heat stored in the ocean, is significantly less than predicted. This is the “travesty”. Please note that the adjustment of the OHC data in the above plot (black line after 2002) makes the missing heat term larger by a significant amount. The problem of balancing the Earth energy budget remains unsolved. If further adjustments are warranted, as I believe, then the problem grows further.

It is useful to plot just the data since the Argo float data were added to the database, in mid-2003 (note the scale as given from the NOAA download which is in per square meter differs from the Levitus scale which is a global sum).

For this period, the slope is 0.00160 GJ/m2/yr or a slight uptrend. In contrast the slope for the previous 36 years (the steepest part of the above plot, ending in 2002) is 0.01075, which is 6.7 times as fast of a rise. Either there has been a sudden deceleration in OHC rise, or there is still a discontinuity at the point where Argo data are added in (I think both are likely). Note that flat periods are present in earlier periods of the data, such as the 1980s, so a flat period is not unprecedented. However, it does match up with the satellite data.

It is useful to compare the above graph to the Argo-only data ( Loehle, C. 2009. Cooling of the Global Ocean Since 2003. Energy & Environment 20:99-102) available at http://www.ncasi.org//Publications/Detail.aspx?id=3152 below which shows a cooling trend.

Commenters have pointed to the Levitus paper above to claim that my result is “wrong” which is interesting since this plot is exactly the Argo data supplied by Josh Willis of NASA JPL. The quality of the Argo data is evident in that the annual cycle with a period exactly 365 days (see my paper cited) is evident in this data but not in the full dataset above it. The Argo data as of my publication showed a cooling trend, but the Argo data are being updated to deal with quality issues so this may no longer be true (data not yet available).

View the original article here

Tisdale: update on ocean heat content

October to December 2010 NODC Ocean Heat Content (0-700Meters) Update and Comments

Guest post by Bob Tisdale

INTRODUCTION

The National Oceanographic Data Center’s Ocean Heat Content (OHC) 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”, Geophysical Research Letters. 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.

This update includes the data through the quarter of October to December 2010. There has been an upswing in the Indian Ocean OHC data. And in the tropical Pacific, there’s been a delayed response to ENSO or a downward shift. Other than those, there are no other major changes with the latest 3 months on which to report.

GLOBAL

The Global OHC data through December 2010 is shown in Figure 1. It continues to be remarkably flat, considering the rise that took place during the 1980s and 1990s.

C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\jrsoc3.jpg
Figure 1

In an upcoming post, I’ll present only the post-2003 data, the era when ARGO floats dominated OHC data.

A CHANGE OF COORDINATES

I’ve changed the coordinates of the Indian Ocean and South Pacific data. The coordinates I was using for the Indian Ocean (60S-30N, 20E-145E) caused too much overlap with the North Pacific and Tropical Pacific data. So I’ve shifted the coordinates so that the Indian Ocean is now represented by 60S-30N, 20E-120E. This required that I shift the South Pacific; it’s coordinates are now 60S-0, 120E-90W.

TROPICAL PACIFIC

Figure 2 illustrates the Tropical Pacific OHC data (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.

C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2vrxw1i.jpg
Figure 2

At least it should. Figure 3 compares tropical Pacific OHC to NINO3.4 SST anomalies (a commonly used ENSO proxy) where the NINO3.4 SST anomalies have been scaled and inverted (multiplied by a scaling factor of -0.15) to help show the relationship. The drop in the tropical Pacific OHC during 2010 is unusual. It should be rising (recharging) during this period. It’s impossible to tell at this time if this is a delayed response or a downward shift.
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\24n2m2r.jpg
Figure 3

The equatorial Pacific, on the other hand, Figure 4, is responding as one would expect.
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\f51snm.jpg
Figure 4

We’ll have to keep an eye on the tropical Pacific OHC data.

INDIAN OCEAN

Figure 5 illustrates the Indian Ocean OHC data. Note the sudden upswing since 2006. It’s odd when we consider the trends for most of the other ocean basins since 2003 are flat or negative. (I’ll illustrate this in an upcoming post.)
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\1fwilz.jpg
Figure 5

The Tropical Pacific OHC dropped and the Indian Ocean OHC rose; one might think warm water has migrated from the Tropical Pacific to the Tropical Indian Ocean. If we combine the Tropical Indian and Pacific subsets and compare it to the Tropical Pacific, Figure 6, we can see the two datasets mimic one another and that the recent drop is suppressed. It’s possible (and likely) there has been some migration of warm water from one subset to the other (likely because the current known as the Indonesian Throughflow does flow between the tropical Pacific and Indian Oceans).
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\1vj2f.jpg
Figure 6

In fact, this transport appears to take place in the animation of NODC OHC from 2005 to 2010, Animation 1, which was taken from the video that’s included in the post The Electric Kool-Aid Ocean Heat Content Animation.
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\5dvryd.jpg
Animation 1

And here’s the YouTube video from that post. (The animation with music starts around the 2 minute mark, so check your volume setting if you’re at work.)

YouTube Link:http://www.youtube.com/watch?v=PUONorBCcxU

But the recent rise in Indian Ocean OHC is not limited to the tropics. Figure 7 compares Indian Ocean OHC to the OHC of the Indian Ocean South of 24S. The OHC of the mid-to-high latitudes also has the sudden surge.
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\9693zl.jpg
Figure 7

And yes, that rise and fall in the OHC of the Indian Ocean South of 24S during the late 1990s does look odd. In fact, if we smooth those two datasets, Figure 8, we can see how unusual that spike appears.
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2pqkrpv.jpg
Figure 8

THE HEMISPHERES AND THE REST OF THE BASINS

C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2j49chc.jpg
(9) Northern Hemisphere
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2w67vbn.jpg
(10) Southern Hemisphere
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\10cqgl5.jpg
(11) North Atlantic (0 to 75N, 78W to 10E)
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2vkfehv.jpg
(12) South Atlantic (0 to 60S, 70W to 20E)
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\r02xrl.jpg
(13) North Pacific (0 to 65N, 100 to 270E, where 270E=90W)
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2w1y0dj.jpg
(14) South Pacific (0 to 60S, 120E to 290E, where 290E=70W)
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\2eb5t39.jpg
(15) Arctic Ocean (65 to 90N)
#####
C:\Program Files (x86)\CartyStudios Corporation\WebMagnates - Auto Blogging Software\data\Mario Gregorio\Watts up with that\nvcw0k.jpg
(16) Southern Ocean (60 to 90S)

SOURCE

All data used in this post is available through the KNMI Climate Explorer:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere

View the original article here