Guest Post by Willis Eschenbach
The best thing about doing climate science the way I do it is that I can study anything I want, and there is always so much more to learn … in the present instance, there’s another year of Argo data, so I thought I’d take another stroll through the world of Argo. The Argo floats sleep a kilometer down, and then every ten days they dive down another kilometer and slowly rise to the surface, measuring temperature and salinity as they go. Then they drop back down a kilometer, and go back to sleep. So start with, here a movie I made up that lets us go diving with the Argo floats down to 2000 metres and back up again …
Figure 1. Movie of the Argo temperatures at standard layers.
One thing I hadn’t realized was how the western sides of the oceans are generally warmer than the eastern sides. Makes sense, because the wind blows in that direction, piling up the warm surface water in the west, and as a result forcing warm water down to deeper levels … at least that’s how I interpret it. I was also surprised by how deep the warm water goes, it’s 18° or so down a couple hundred metres in many places.
The Argo floats are indeed a marvel, but they do have their limitations. One of the limitations is that there are only about 3,500 of them in the ocean at any one time, and the ocean is a very big place. As a result, I don’t know how much trust we can put in the results … but let’s look at them anyhow.
First off, here’s what’s going on at the surface. The data says that there is a small warming of about a tenth of a degree over the decade. But as with many things in climate, the reality is more complex. Here is a breakdown of the surface temperature into the seasonal and residual components:
Figure 2. Argo Surface Temperatures. Top panel shows raw data. Middle panel shows the average changes (seasonal component), month by month, as an anomaly. The bottom panel shows the raw temperature less the seasonal component, again as an anomaly.
Now, despite the fact that there is a trend visible, as detailed in the bottom of Figure 2, you can see that the temperature dropped from the beginning of the record in January 2005 to about January 2008. Then for two years, the temperature rose rapidly … and dropped again for the next two years, and then rose again to the end of the record.
Because of this variation, I’d say that drawing any conclusions from the apparent tenth of a degree per decade “trend” is very premature. Let me give you another example of this same problem. Figure 3 shows the temperature trends at the surface, in degrees per decade.
Figure 3. Surface temperature trends by area. Dark blue and green show cooling.
Now, there’s a number of interesting things about this map. First, most of the ocean isn’t doing a whole lot, either trivially warming (cyan) or trivially cooling (light green).
Next, there are isolated areas that are significantly cooling—off the southern tip of Africa, near China, down in the Antarctic, and most curiously, the North Atlantic.
Similarly, there are isolated areas of warming—west of australia, off of Japan, west of Panama, east of Argentina, and off the northeast US.
Finally, the tropics by and large is not warming in any significant manner. This is in line with my hypothesis that tropical clouds greatly constrain the temperature variations in the tropics.
Anyhow, that’s what I learned from looking at Argo. I learned once again that linear trends are always deceptive … and a lot besides that. Always more to find out in this field, I guess that’s why they call climate the “settled science” …
My best wishes to all of you, warm oceans and crisp evenings, and time with those you love,
w.
As always, let me request that if you disagree with someone, please QUOTE THEIR EXACT WORDS. This allows everyone to understand your objection
ARGO DATA: It’s big, it’s ugly, and it’s scattered, and you need to download July 2013 onward month by month. In any case, it’s here, as .ncdf files.
MY PREVIOUS POSTS ON ARGO, ordered by date.
Krige the Argo Probe Data, Mr. Spock!
A few weeks ago I wrote a piece highlighting a comment made in the Hansen et al. paper, “Earth’s Energy Imbalance and Implications“, by James Hansen et al. (hereinafter H2011). Some folks said I should take a real look at Hansen’s paper, so I have done so twice, first a quick look at “Losing Your…
The Argo floats are technical marvels. They float around below the surface of the ocean, about a kilometre down, for nine days. On the tenth day, they rise slowly to the surface, sampling the pressure, temperature, and salinity as they go. When they reach the surface, they radio home like…
Like Jason, I proceed into the unknown with my look at the Argo data, and will post random notes as I voyage. Come, my friends, ‘Tis not too late to seek a newer world. Push off, and sitting well in order smite The sounding furrows; for my purpose holds To…
Following on my previous post, “Jason and the Argo Notes”, just a couple of graphs in passing: Figure 1. Argo surface temperatures, northern hemisphere. Colors show the latitude of the floats, from red at the Equator to blue in the north. Click on image for full size version. UPDATE: several…
Argo and the Ocean Temperature Maximum
It has been known for some time that the “Pacific Warm Pool”, the area just northeast of Australia, has a maximum temperature. It never gets much warmer than around 30 – 31°C. This has been borne out by the Argo floats. I discussed this in passing in “Jason and the…
I got into this investigation of Argo because I disbelieved their claimed error of 0.002°C for the annual average temperature of the top mile of the ocean. I discussed this in “Decimals of Precision“, where I showed that the error estimates were overly optimistic. I wanted to know more about what the structure of the…
Argo, Latitude, Day, and Reynolds Interpolation
This is another of my occasional reports from my peripatetic travels through the Argo data (see the Appendix for my other dispatches from the front lines). In the comments to my previous post, I had put up a graphic showing how the January/February/March data for one gridcell varied by latitude…
Bob Tisdale has discussed a variety of issues with the hemispheric and basis-by-basin Levitus summary of the ARGO data in his excellent post here on WUWT. I wanted to take a larger look at at the global ocean data, to provide it with some context. After following a variety of…
I’ve been thinking about the Argo floats and the data they’ve collected. There are about 4,000 Argo floats in the ocean. Most of the time they are asleep, a thousand metres below the surface. Every 10 days they wake up and slowly rise to the surface, taking temperature measurements as…
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Amazing how homogenous the temperature is as it approaches 2000 m.
It is noted at NOAA that 52% of the ocean volume is below 2000 m. (WUWT July 4, 2013)
I fail to see a lot of “missing heat” When 52% of the volume of the ocean is somewhere between a few degrees negative and 5C. That’s a pretty freaking large heatsink/buffer– Even if it’s not well mixed on our timescale.
Great post and images / movies, a decision to check out a Willis post is always rewarded!
I love the animation of ocean temperature with depth down to 2000m. So the Pacific basin at mid depths around 2000m is colder than the Atlantic or Indian – who knew?
The plot in the lowest of Willis’s three charts is what Mike Haseler the Scottish Sceptic would call noise. Another sceptic whose name may not be mentioned on this site might even call it a sine wave.