Guest Post by Willis Eschenbach
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 sail beyond the sunset, and the baths Of all the western stars, until I die.
I have no great insights at this point, just some interesting results. Thanks to a commenter who pointed me to where to get the Argo data in one block. It’s at the Asia-Pacific Data-Research Center.
I downloaded it, and I’ve looked first at the file containing the surface data. It’s where I swim, so it’s the most interesting data to me. Figure 1 shows all Argo measurements of the ocean surface temperature taken to date.
Figure 1. All Argo ocean surface temperature data. There have been 696,872 Argo measurements to date of the ocean surface temperature.
So far, so good. The results look real, which is always good to see, it means I’ve graphed them up properly. You can see the warm ocean along the coast of Europe, for example. But there is one curiosity about the Argo data.
Here’s the oddity. I took the data arranged by latitude as shown in Figure 2. I averaged it by 1° latitude bands, and then took an area adjusted average to give a global mean. The mean is 19.7°C ± 0.02 (95% CI).
Figure 2. All Argo ocean temperatures, sorted by latitude. NOTE: several people commented correctly below that I had not included the variation in ocean area by latitude band in the calculations. They are correct, I was wrong, and the actual corrected 60N-60S average is slightly higher, at 19.9°C.
Note that there is an obvious upper limit to the ocean temperatures, the “flat-top” on the graph at just above 30°C. No matter how much incoming solar there is, the ocean doesn’t get any warmer than that. This provides a “cap” on how hot the ocean can get. Above that temperature, any extra incoming energy is converted to latent and sensible heat, rather than warming the surface.
But I digress, that part’s just interesting. It’s not the curiosity.
The curiosity is the other ocean data sets give the following values for the average ocean surface temperature 2000-2011:
Hadley Center HadISST1 60N – 60S: 20.5°C ± 0.02°C (95%CI)
Reynolds Optimally Interpolated SST 60N – 60S: 20.4°C ± 0.02°C (95%CI)
NCDC Extended SST 60N – 60S: 20.3°C ± 0.02°C (95%CI)
The curiosity is that the Argo average ocean surface temperature data is significantly cooler than the other datasets, half to three-quarters of a degree …
Always more to learn. I do love real data. Look how much colder and more uniform the Southern Ocean is than the northern oceans, for example. Fascinating stuff.
Best to everyone,
[UPDATE]
The data I used is available at the website listed above, identified as “Near-real time Argo profile data interpolated on standard levels”. It’s the largest file on this page, 895 Mb, titled “Argo_TS.tar”.
The info sheet detailing the arrangement of the data is here.
It’s a tarball containing all of the depth files, one for each layer. The one I used was the zero depth file, “Argo_TS_0000.dat”. I downloaded them all, because I wanted the full set. If you only want surface temps you can download just that one file.
To read it in once it was downloaded (in the “R” computer language), I used:
depthcolumns=c("Longitude", "Latitude", "Level", "Depth", "Julian", "Temperature", "Salinity", "Potential Temperature", "Potential Density", "Dynamic Depth Anomaly", "Spiciness", "Extrapolation", "Error Temperature", "Error Salinity", "Error Potential Temperature", "Error Potential Density", "Error Dynamic Depth Anomaly", "Error Spiciness", "Ocean Code", "Region Code", "Argo Float ID", "Cycle Number", "Dynamic Depth", "Dynamic Depth-2")
depthwidths=c(9, 9, 3, 7, 10, 9, 9, 9, 9, 9, 9, 2, 11, 11, 11, 11, 11, 11, 2, 3, 8, 4, 9, 9)
depthinfo0=read.fwf("/Users/willis/Argo_TS/Argo_TS_0000.dat",depthwidths, col.names=depthcolumns)
You’ll need to change the filepath in the final line to wherever you have put the “Argo_TS_0000.dat” file.
w.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Willis
There seems to be some cross purpose developing here, so let me make my position clear:.
1. As I mentioned in one of my previous posts, I make no observation whatsoever on your data analysis. This is a work in progress and accordingly, at this stage, I have given it little attention. I consider the exercise that you are embarking upon to be useful and interesting.
2. As, I mentioned in one of my previous posts, my comments are based upon the review of thousands of ship’s logs containing hundreds of thousands of entries. For clarification, I am not basing my comments on the records/data set out in the linked web sites I referred to in my post of February 10, 2012 at 7:06 pm. I merely linked that data to show general support to my contention that the various ocean in many parts of the world have temperatures exceeding 30degC and up to 35 deg C.
3. Ships take temperature data very differently to ARGO. These days, a ship measures the sea water temperature used for engine cooling. This water is drawn at a depth that will depend upon the design and configuration of the vessel, whether the vessel is sailing laden, partly laden or in ballast and how the Master has decided to trim the vessel. In broad terms, this is at a depth of 10m (I use “broad” widely). Log entries are recorded usually every 4 hours. If a vessel is sailing at 10 knots, it will effectively sample sea water temperature every 40 nautical miles. If at just over 12 knots this will be every 50 nautical miles. Thus if a voyage is 6,000 nautical miles, there will be say 120 temperature measurements (assuming an average speed of just over 12 knots). For commercial reasons, ships will tend to sail between two ports in the shortest geographical manner, weather and safe navigation permitting. Accordingly, ships will tend to sail in defined highways (sea lanes/routes). Thus you get a great many lateral measurements but only over a relatively small strip of ocean.
4. As I mentioned in one of my previous posts, I am not suggesting that ARGO in someway erroneously measures ocean temperatures or that your statistical analysis of the distribution of the ARGO data is erroneous nor even if you were to include ship data this would lead to the average temperature of 19.7 deg C being altered.
5. I am merely commenting on one of the scientific conclusions that you drew from your review of the data. You asserted that “Note that there is an obvious upper limit to the ocean temperatures, the “flat-top” on the graph at just above 30°C. No matter how much incoming solar there is, the ocean doesn’t get any warmer than that. This provides a “cap” on how hot the ocean can get. Above that temperature, any extra incoming energy is converted to latent and sensible heat, rather than warming the surface..”
6. I have no gripe with the first sentence, but I join issue with the scientific (not statistical) conclusion that you drew; namely that there is some physical process at work which means that “No matter how much incoming solar there is, the ocean doesn’t get any warmer than that [30 degC]. This provides a “cap” on how hot the ocean can get. Above that temperature, any extra incoming energy is converted to latent and sensible heat, rather than warming the surface..” I consider that statement to be erroneous.
7. As stated, my position has no bearing on your statistical analysis. My position is directed solely to whether ‘no matter how much solar is inputted, the ocean cannot get hotter than 30 deg C’ If that contention was right, the prospects of cAGW would be greatly diminished. The reason for this is that it is the tropical oceans that are the heat pump of the planet and it is their heat that is circulated around the globe. If the tropical ocean could not get hotter than your figure then this would potentially place a major restriction on how much warming can take place.
8. As stated in one of my previous posts, I do not dispute that there is a temperature ceiling that the oceans can obtain (assuming solar and cloudiness remains broadly stable). I also accept that the mechanism behind such cap put forward by you (essentially latent & sensible heat involved in evaporation) would play a part in imposing the cap.
9. I disagree with you in two important respects. First, that the cap is set at 30 degC. Second, that the physical process behind the cap is solely the process that you mentioned. In fairness to you, you do not state that the ‘evaporation process’ is the sole process involved. Dealing with the second point, you will note from numbered para 3 of my post of February 10, 2012 at 8:12 am that I suggest that other processes are involved (such as currents and overturning) and that it a combination of physical processes that would lead to a cap.
10. Turning to what appears to be the most contentious issue; namely, is the cap on ocean temperatures 30 deg C or not? In this regard, I am not arguing with your histogram. I do not dispute the location of ARGO buoys is such that they have sampled rather few locations where the water temperature exceeds 30 deg C (only about 10,000 have sampled in excess of 30degC). I am just saying that the ocean can get warmer than 30degC and does so (if nothing else witness the nearly 10,000 ARGO samples), and that the physical mechanism you suggested does not result in a cap of 30degC temperature (if nothing else witness the nearly 10,000 ARGO samples).
11. I do not wish to get into a protracted debate as to what is an enclosed sea, a semi enclosed sea and open ocean (which in any event are terms that did not appear in your original posting and which were not used by you as qualifying your statement). This is somewhat subjective and depends upon the correct definition of the terms used, In this regard, I am not sure that these are even terms of art with an accepted definition. Some commentators (for example Philip Bradley says: February 10, 2012 at 7:56 pm) suggests that the hydrological process is different over semi enclosed and enclosed oceans compared to open seas. Much study would have to be done before any firm conclusions could be drawn, although for the main part it is the oceans and the air over oceans that influence the air above the land, not the other way around. Further, how far from land does the influencing effect from the air over land propagate? 10 miles from the coast, or 50, 100 etc? These are difficult issues to address without extensive study and I am not going to fire from the hip.
12. I do not have to deal with these points since it is clear that even in open ocean (eg the Atlantic off the West coast of Africa temperatures of up to 35 degC are recorded, and in the Indian Ocean both off the East coast of Africa and off the West coast of India temperatures of 34 degC are recorded. This confirms that the cap on open ocean temperatures (no matter what processes or processes are involved in placing a cap) is not 30degC but not less than 35degC.
13. Indeed, we know (or ought to know) that the hydrological process that you identified as placing a cap of 30 degC as the maximum to which the oceans can get is wrong since in prehistoric times it is accepted (or at any rate generally accepted) that the tropical ocean was far warmer than it is today. That is notwithstanding that back then solar may have been weaker.
14. In summary, I remain of the firm view (and this is based upon extensive review of ship’s logs for some 25 years) that the open ocean is not capped at a temperature of 30degC and I respectfully suggest that you complete your statistical analysis before we start drawing conclusions as to what ARGO tells us about the scientific processes that may influence our climate.
David says: February 11, 2012 at 5:58 am
//////////////////////////////////////////////
I suspect that there is quite some merit in the points raised.
Sea temperature can be very local and variable and no doubt warm waters have much to do with currents and topography
richard verney says:
February 11, 2012 at 8:22 pm
David says: February 11, 2012 at 5:58 am
//////////////////////////////////////////////
I suspect that there is quite some merit in the points raised.
==========================
Richard, I really do not think Willis was asserting more then what I stated in that comment. He has acknowledged that the ocean DOES get warmer then “about” 30C, just that the data points drop off very rapidly beyond this, so your only possible quibble is how often. BTW, if you can find this paper, (Newell & Dopplick’s (1979) you may wish to read it. I have a few notes from it somewhere, but I do not have a link to the paper.
Willis,
I prefer this line:
“To follow knowledge, like a sinking star,
Beyond the utmost bound of human thought.”
But it is without doubt a great poem for older men like me.
But really, Jason?
Do you not see the evolving climate debate as the new Troy then?
Certainly there seem to be heroes and casualties on both sides of the divide.
Does not fair Helen represent the truth to be contested?
Have not we traded a horse for a Hockey Stick?
How would you cast Moncton, Curry, Gore et al?
William M. Connolley says:
February 10, 2012 at 3:51 am
>>
> I averaged it by 1° latitude bands, and then took an area adjusted average to give a global mean
Assuming you mean that you averaged all the floats in a given latitude band together, that would be a problem, since there is clearly structure in longitude; you’ll have biased your numbers by float-count-density.
>>
Well, I never thought I’d agree with Connelley about climate but I would agree with his point here.
More over, the argo floats are not evenly deployed. One of the main aims was to fill in coverage of some of the large expanses of ocean that got very little or only seasonal coverage form shipping.
If you are taking an average of argo , even band averaged, you are averaging with a regional and seasonal bias w.r.t the other records and it is to be expected that there is a difference with other SST records.
It’s worth noting but I don’t know what conclusions can be drawn from that.