Image Credit: Bob Tisdale – bobtisdale.wordpress.com
By WUWT Regular Just The Facts
The recent Adjustments/Corrections to the HadCRUT4 and CRUTEM4 Temperature Data Sets by the Met Office Hadley Centre and Climatic Research Unit got me thinking about the cumulative impact of Adjustments/Corrections on our temperature records. Bob Tisdale then triggered the first vein of this analysis when he recently produced and provided the graph above, which compares the ICOADS (International Comprehensive Ocean-Atmosphere Data Set) v2.5 data set to HadSST3, HADISST and ERSST.v3b. ICOADS is the original unadulterated Sea Surface Temperature record. HadSST3, HADISST and ERSST.v3b, all include adjusted/corrected ICOADS data, e.g.:
[Note: Bold and non-link underlines below are mine. I am testing out a new three speed review approach, i.e. if you really want to know it, read it all, if you want an overview, read the underlines and non italics, if you want the key concepts, read the bold and non italics. Please let me know in comments if this approach works for you.]
HadSST3 The SST data are taken from version 2.5 of the International Comprehensive Ocean-Atmosphere Data Set, ICOADS (external web page), from 1850 to 2006 and on GTS observations from 2007 onwards. HadSST3 is produced (a slightly more detailed description) by taking in-situ measurements of SST from ships and buoys, rejecting measurements that fail quality checks, converting the measurements to anomalies by subtracting climatological values from the measurements, and calculating a robust average of the resulting anomalies on a 5° by 5° degree monthly grid. After gridding the anomalies, bias adjustments are applied to reduce the effects of spurious trends caused by changes in SST measuring practices. The uncertainties due to under-sampling and measurement error have been calculated for the gridded monthly data as have the uncertainties on the bias adjustments following the procedures described in the paper.
The HadSST3 page references this paper “Improved Analyses of Changes and Uncertainties in Sea Surface Temperature Measured In Situ since the Mid-Nineteenth Century: The HadSST2 Dataset“, Rayner, et al., 2005, as the basis for their adjustments/corrections. It states within that:
a. Bias correction and its uncertainties Seawater has been sampled for temperature measurement on board ship by various different means at different times. This change from using insulated (wooden) to uninsulated (canvas) to partly insulated (rubber) buckets, engine room intakes, and hull sensors, along with changes in ships speeds, has introduced changing relative biases into the database. Folland and Parker (1995) developed corrections to be applied to SST data between 1856 and 1941 to ameliorate the effect of these changes and to bring the older data into line with data from the modern mix of measurement methods. For details of the development of these corrections, the reader is referred to Folland and Parker (1995).
Here’s Parker, Folland, M. Jackson (1995) paper MARINE SURFACE TEMPERATURE: OBSERVED VARIATIONS AND DATA REQUIREMENTS Here are some of the adjustments/corrections detailed within:
“Overall global warming in SST between the 1860s and the 1970s is about 0.3 °C greater in the present analysis than in Folland et al. (1984), mainly owing toreduced early corrections applicable under the assumption of the predominant use of wooden buckets (Section 3).”
“The largest, positive corrections are in early winter (December) over the Gulf Stream and the Kuroshio, where warm water, cold dry air, and strong winds cause rapid evaporative heat loss from the buckets. The corrections approach 1 °C by 1940 in these regions in early winter. Corrections are also large (around 0.4 °C to 0.5 °C by 1940) in all seasons in the tropics because of the high rate of evaporation when SST is high. Some negative corrections are made in mid latitudes in summer, mainly where the mean air temperature around the bucket exceeds the mean SST.”
Here’s their Figure 7, which shows the impact of their adjustments/corrections.
“How do we know that these corrections are trustworthy? The agreement of SST anomalies with largely independently corrected NMAT anomalies (Section 7 and Figure 7) is the strongest support to the results, and suggests that the impacts of future refinements and reduction of uncertainties in this area will be small.”
So who do you think provided the “largely independently corrected NMAT” SST anomalies, which are “the strongest support to the results”? Wait for it…
“Folland et al. (1984) applied corrections to NMAT to compensate for the historical increases of the average height of ship’s decks. These rose from about 6 m before 1890 to 15 m by the 1930s and 17 m by the 1980s. The corrections, based on surface layer similarity theory, removed a spurious cooling of about 0.2 °C between the late nineteenth century and 1980. On the other hand, Jones et al. (1986) used anomalies (not actual values) of regional, mainly coastal, land surface air temperature to adjust anomalies of nearby MAT. This was possible because anomalies of MAT and nearby ‘coastal’ land surface air temperature are found to be similar in recent data over periods as long as a decade, even though the absolute values differ considerably. However, because Jones et al. (1986) used COADS summaries, they were unable to separate NMAT from day MAT which are affected by historically varying, on-deck solar heating: their corrections therefore differed from those of Folland et al. (1984). In both these early studies, about 0.5 °C was subtracted from MAT for 1942-5, a period of non-standard measurement practices owing to war. “
Yes, that Jones et al. (1986) reference is Phil Jones, and Tom Wigley too, at the Climatic Research Unit (CRU), University of East Anglia (UEA). And it turns out that Rayner, Folland and Parker all worked at the Hadley Centre, Met Office.
This 1992 Jones and Wigley paper “Corrections to Pre-1941 SST Measurements for Studies of Long-Term Changes in SSTs” appears to be a seminal work in the development of Sea Surface Temperature record adjustments/corrections:
Many factors can influence a sea surface temperature reading (Barnett, 1985; Jones et al., 1986; Bottomley et al., 1990; Jones et al., 1991). Some of these introduce random errors while others result in systematic, non- cancelling errors. The most important factor is the method of collecting the sample, with the two basic methods being to haul a sample on deck with a bucket, or to measure the temperature of the intake water used for engine cooling. Here, we are concerned with bucket measurements. These are affected by the kind of bucket used, the exposure of and physical conditions surrounding the bucket, how long the bucket was left before reading the thermometer, and ship speed.
In COADS we do not have detailed information concerning the methods of measurement, nor any indication of what method was used for the individual readings that make up the data. There is,nevertheless, strong evidence that readings before 1940 were predominantly bucket measurements, while those since 1945 were predominantly intake measurements (Jones et al., 1986). Furthermore, it is likely that the major difference between the data for these two periods is the non-climatic bias due to the evaporative cooling of the canvas bucket, an effect which would clearly cause pre-1940 data to be cooler than post-1945 data (Jones et al., 1991).
In order to derive correction factors for the bucket-derived temperatures, we have modified the model developed by Folland and Hsiung, 1987 and Bottomley et al., 1990, to estimate the cooling of an uninsulated canvas bucket. The main difference between our work and that of Folland and Hsiung (1987) is that we have solved the governing equations analytically. This makes application of the model less demanding computationally, and it allows us to perform a variety of analyses.
2. The bucket model
If you have not already, you really should take a look at Section 2. “The Bucket Model” within Jones and Wigley’s 1992 paper, as it is a classic work in gibberish…
Continuing…
4. Correcting SSTs using the bucket approach
4.1 Optimum exposure time
For 1905-40, SSTs may be corrected using the evaporating bucket model. Although average ship speed probably varied over this period, within the range of likely values ship speed does not noticeably affect the implied exposure time. We have used a ship speed of 7ms-1. Wind speeds of 60% of the anemometer speed produce slightly better results than the 40% reduction case, and lead to slightly lower optimum exposure times (by less than 1 minute on average) so we have used this value. As the most likely exposure time lies in the range 3-6 minutes, we use 4 1/2 minutes in making final corrections.”
“4.2 The final correction factors
Final correction factors depend on the location, month and year. These variations are summarized in Figures 3 to 5. Correction factors vary slightly from year to year depending on coverage changes. Figure 3 shows mean correction factors for the Northern Hemisphere. Southern Hemisphere mean corrections are shown in Figure 4. The transition from small corrections in the early decades to larger corrections after 1905 is due to the change from wooden (i.e., better insulated and assumed to require no correction) to un-insulated buckets. Correction factors are largest in the winter half year. Northern Hemisphere corrections show slightly larger season-to-season variations. Figure 5 shows how the “winter” (JFM) and “summer” (JAS) – using Northern Hemisphere seasonal labels – corrections vary with latitude. Correction factors are lower in higher latitudes in general, particularly in the 45-75°N band where the “summer” corrections are near zero.”
It appears that the Team that brought us Climategate, was hard at work adjusting/correcting the Sea Surface Temperature record back in the 80s and 90s…
Here Jones and Briffa team up to summarize the purported basis of the Sea Surface Temperature record adjustments/corrections in their paper, “Global Surface Air Temperature Variations During the Twentieth Century: Part 1, Spatial, Temporal and Seasonal Details“, P. D. Jones and K. R. Briffa, 1992.
“Problems with the homogeneity of sea surface temperature (SST) data arise due to differences in the method of sampling the sea water. Before the second world war the sea water was collected in an uninsulated canvas bucket. There was a delay of a few minutes between sampling and measuring the temperature. During this time the water in the bucket generally cooled slightly by evaporative means. Since the second world War most readings have been made in the intake pipes through which sea water is taken onboard ships to cool the engines. This change in measurement technique was quite abrupt at around 1941, although there are still significant numbers of bucket measurements (using plastic and thus better insulated buckets) made today and some intake measurements were made prior to the second world war.
Comparative studies of the two methods indicate that bucket temperatures are cooler by 0.3-0.7″C (James and Fox, 1972). Correcting the SST data for this measurement change may seem, at first, seem an intractable problem. Folland and Parker (1990; 1991) of the UK Meteorological Office, how- ever, have developed a method for correcting the canvas bucket measurements based on physical principles related to the causes of the cooling. The cooling depends on the prevailing meteorological conditions, and so varies according to the time of year and location. Although the cooling is therefore a day-to-day phenomenon, the various influences are basically linear, so cooling amounts can be calculated on a monthly basis. The main free parameter is the elapsed time between sampling and reading. This is generally unknown and must be estimated from the data. The primary assumption in this estimation is that there have been no major changes in the seasonal cycle of SSTs over the period of record. Since the amount of evaporative cooling has a strong seasonal cycle in many parts of the world, an optimum exposure time can be chosen; namely that which minimizes the residual seasonal cycle in the corrected data.As a check on the validity of the method, the implied optimum exposure time turns out to be quite consistent spatially (see Jones and Wigley, 1990; Jones et al., 1991 for more details).
The major problem with the technique is that it is not known with any certainty what types of buckets were used to take measurements during the nineteenth century. Assuming canvas buckets rather than wooden buckets (which are better insulated) leads to corrections which infer SSTs warmer than land temperatures by about 0.2″C. The discrepancy almost disappears if wooden buckets are assumed. Although there is documentary evidence to support wooden bucket use during the mid-nineteenth century, considerable doubt remains about the transition from wooden to canvas buckets. The seasonal-cycle elimination method is not precise enough to choose between the two possibilities. The corrections used here have been derived using the wooden bucket assumption in the nineteenth century (see Jones et al., 1991 for details).
“The major problem with the technique” and “The Bucket Model” are that they rely upon an array of assumptions and estimations, which are based on very limited empirical data, and were made by people like Phil Jones and Tom Wigley, who have apparent biases, and appear to have been working the propagate the Catastrophic Anthropogenic Global Warming narrative since the early eighties. It is interesting to note that the Jones et al. papers on Sea Surface temperature adjustments/corrections do not appear listed within the otherwise quite encompassing collection of Jones’ work on the UEA website.
Steve McIntyre has written extensively about bucket adjustments starting back in 2005, i.e. Changing Adjustments to 19th Century SST;
You may recognize Folland as a major IPCC author (Folland et al. [2001] is sometimes the citation). SST sampling is not homogeneous – it changed from buckets to engine inlets – engine inlet temperature ran a little hotter. Both canvas and wooden buckets appear to have been used. There are millions of SST measurements and how the measurement was done is not known for most measurements (as far as I can tell.) There are two main adjustments in Folland et al. The first is a one-time adjustment for from buckets to engine inlets in December 1941. This is premised on a comparison between the “corrected” NMAT temperature [ I haven’t checked what these “corrections” are] and the uncorrected SST temperatures.
Buckets and Engines, The Team and Pearl Harbor, Bucket Adjustments: More Bilge from RealClimate, Rasmus, the Chevalier and Bucket Adjustments, Did Canada switch from Engine Inlets in 1926 Back to Buckets?;
CA readers are aware that I discussed bucket adjustments on a number of occasions long before Thompson et al 2008, in particular, questioning the absurd IPCC assumption that all SST measurements switched from buckets to engine inlet on the day after Pearl Harbour. In March 2007, a year before Thompson et al 2007, in light of new historical information bucket usage, I provided a scoping estimate of the potential impact of a different changeover scenario, based on then-just-published Kent et al 2007. The direction of the impact is precisely the same as that shown in the present HadCRU estimates over 4 years later. The difference between the two appears to be that the present HadCRU estimate assumes that bucket changeover impact has ended by 1970, while, in my 2007 post (based on Kent’s evidence of widespread bucket usage in the 1970s), I presumed that the changeover continued until the 1990s.”
and HadSST3;
A new HadSST3 version has been recently published. It starts the process of unwinding Folland’s erroneous Pearl Harbour bucket adjustment, an adjustment that has been embedded in HadSST for nearly 20 years.
Folland’s erroneous adjustment had been originally criticized at CA in 2005 here and further discussed at length in March 2007 at CA here, a post in which I observed that no climate scientist had made any attempt to validate Folland’s bizarre adjustment and that correcting Folland’s error (through a more gradual and later changeover to engine inlets than the worldwide overnight change that Folland had postulated after Pearl Harbour) would have the effect of increasing SST in the 1950s, in turn, potentially eliminating or substantially mitigating the downturn in the 1950s that was problematic for modelers.]
However, not until Thompson et al 2008 (submitted Jan 2008; published May 2008) was the problem with the Folland adjustment clearly acknowledged by the “community”. The importance of Thompson et al in resolving the problems arising from the Folland adjustment were credited by Susan Solomon and Phil Jones in the commentary accompanying the Nature article.) Both lead author David Thompson and co-author Mike Wallace, though very prominent climate scientists, had negligible (or no) publishing history on the topic; as one commenter at James Annan’s blog put it, they came out of “left field”. Thompson was an ozone specialist. The other co-authors, John Kennedy of the Hadley Center and Phil Jones of CRU, were, of course, actively involved in the field.
Now over three years later, in a new SST edition (HadSST3), the Hadley Center has accepted and implemented Thompson et al’s criticism of Folland’s Pearl Harbour adjustment. Instead of implementing an overnight changeover to engine inlets in December 1941 as before, the changeover is now phased in through the mid-1970s. This results in changes to SSTs between 1941 and ~1975.
However, Steve does not appear to have dug too far into the pre-1945 adjustment/correction highlighted by Bob Tisdale’s graph.
One piece of this puzzle I can’t seem to find is the oft cited Bottomley et al., i.e.: Bottomley, M., C. K. Folland, J. Hsiung, R. E. Newell, and D. E. Parker, 1990: Global Ocean Surface Temperature Atlas. MIT Press, 20 pp. plus 313 plates. According to the Global Ocean Surface Temperature Atlas GOSTA:
This is the January 1993 version of the Global Ocean Surface Temperature Atlas (GOSTA) (Bottomley et al., 1990) referred to as ATLAS7 or MOHSST5. The data in this atlas are a compilation of marine observations from the United Kingdom Meteorological Office Main Marine Data Bank with some additional data from the US Fleet Numerical Oceanography Center. The Atlas includes the climatology of sea surface temperature (SST) and the difference between marine nighttime air temperature (NMAT) and SST. These climatologies are based on data collected between 1951 and 1980. Also included are SST and NMAT monthly anomalies from 1856 to 1991. The data were corrected to remove what are believed to be observational biases due to changes in instrumentation. These correction are based on scientific research summarized in the introduction to the hard-copy version of GOSTA (Bottomley et al., 1990). All data are presented on a 5 by 5 degree grid wherever data existed. The climatology of SST can be made available on a 1 by 1 degree grid.
The quality of marine observations is thoroughly discussed in the hard copy volume of GOSTA as well as in the references therein. The user should note that the data were collected using a variety of instruments and observational procedures aboard vessels of different shapes and dimensions.
Here is the GOSTA data, however I would like to see the “scientific research summarized in the introduction to the hard-copy version of GOSTA (Bottomley et al., 1990).” to understands what those adjustments/corrections are based on, but even Google Scholar comes up dry.
If anyone can find an electronic copy of Bottomley et al., 1990 and/or can offer additional information on the adjustments/corrections made to the to the Sea Surface record, please post them in comments.
Steve McIntyre says:
May 25, 2013 at 3:51 pm
By the way, I once requested an out-of-print publication on SST from CRU. The request was in Climategate 1. The request to the CRU library was sent to Jones and forwarded to Mann, but i did end up with a pdf of Farmer et al 1989, one of the more technical works on bucket adjustments.By the way, I once requested an out-of-print publication on SST from CRU. The request was in Climategate 1. The request to the CRU library was sent to Jones and forwarded to Mann, but i did end up with a pdf of Farmer et al 1989, one of the more technical works on bucket adjustments.
Steve, is this Farmer et al., 1989 article the one you’re referring to?
http://www.cru.uea.ac.uk/cru/pubs/pdf/Farmer-1989-NERC.pdf
Just The Facts,
I also spent a long time searching for Bottomley et al., 1990 with no success. If you do manage to get hold of it, could you post a .pdf?
By the way, some readers may be interested to know that the “R. E. Newell” of Bottomley et al., 1990 was one of the more prominent sceptics of CAGW in the 1980s – Prof. Reginald E. Newell of M.I.T. (who died in 2002, at the age of 71).
Here’s a clip of an interview with him from the 1990 “Greenhouse Conspiracy” Equinox documentary for the UK’s Channel 4: http://www.youtube.com/watch?v=4Btd6L31ZYg&t=35m15s
If anyone hasn’t seen the “Greenhouse Conspiracy” documentary and has a spare 50 minutes, it’s well worth watching the whole documentary. Just click on the beginning of the scroll bar on the YouTube link above. I think it’s interesting how many of the criticisms of CAGW theory which were been made then, are still valid… It’s also interesting to hear the defenses of CAGW by e.g., Prof. Tom Wigley
Steve McIntyre: “SST adjustments is also something that solar bugs also should be interested in. In the early 1990s, George Reid had linked solar changes to the then SST record: see extracts from IPCC here http://climateaudit.org/2007/01/16/ipcc-and-solar-correlations. These correlations were hugely diminished by Folland’s bucket adjustments.”
I also had a closer look a periodicity in SST and used ICOADS for this precise reason. Despite eventual doubts over long term biases ( and there clearly are some ) Hadley data processing has notable effects on the frequency spectrum that has never been official assessed, let alone validated.
http://climategrog.wordpress.com/2013/03/01/61/
At the end I added an appendix with a comparison of HadSST3 ICOADS frequency spectra.
It is not completely distorted but there are significant changes. In this context I would have far more confidence in ICOADS than any of the reprocessed time-series.
I, too, have been a scuba diver. Temps can vary from near air temp (and hot in summer…) at the surface down to near constant cold over not very much distance. (In one lake, the first thermocline at about 5 feet was from about 85 F to 70F or so, but at 25 feet down it was damn cold and I’d guess about 55 F to 60 F. In the ocean I’d expect a bit less stratification. HOWEVER:
In reading the above I didn’t see much mention of the disruption of the layering caused by the passing of a ship.
There’s a huge screw at the back of the ship churning cold lower into warm upper layers. There is a large sideways displacement that then rushes back in behind the ship. A whole lot of mixing going on. How does that change what is measured?
What happens when ships form up into war time convoys instead of singletons, each now measuring the ‘mixed’ waters of the front of the convoy?
To second the comment above about ship trim: Ships do NOT measure surface temperature.
BTW, proceeding down the link from Jeez ( http://iridl.ldeo.columbia.edu/SOURCES/.GOSTA/ ) to the GOSTA “CD Rom on line” link gives this message:
http://podaac.jpl.nasa.gov/cdrom/gostaplus_binary/order.htm
Notice that the “new” web site address given is the same as the start segment of the one giving the error message…
So no telling what they’ve done with the data now… (but isn’t that the one constant in “climate science”…)
IMHO, the SST shows the same general pattern. Methods and data so lousy it’s nearly useless for generating panic; then “adjusted” in questionable to mindless ways as an excuse to narrow the giant error bands into tiny little things (and clearly wrong…) so one can claim a ‘trend’ that is only an artifact of differential error band fudge.
In other words: It is all “dancing in the error bands on the head of a pin”.
Here is the graph at the end of the article I linked above. It is a good example to the spectral distortion of Hadley processing.
http://climategrog.files.wordpress.com/2013/03/icoad_v_hadsst3_ddt_n_pac_chirp.png
Like I said , they have not destroyed the spectral content but have made significant changes.
I first discovered what looked like an interesting link between N. Pacific and N. Atlantic SST in hdaSST3 in an autocorrelation plot of the two. I got quite excited about my discovery of an important interconnection and went digging.
Somewhere along the line I decided to see whether the same thing was visible in the original ICOADS data, maybe it would be clearer signal.
It disappeared !
It seems that I had detected a “teleconnection” in Hadley processing, not the climate.
Now if one of the most significant peaks in the Pacific is at a frequency that Scaffeta has identified as being an effect of the presence of the Moon of Earths orbit around the Sun, shifting it sideways just a bit will destroy any evidence of this possible causal link.
This is the strongest peak at around the decadal time scales and so is a major climate feature in the biggest ocean on Earth.
It gets replaced by something a little short of 8year that does not even exist in the original data.
Now that must be a pretty effective means of ensuring that not even objective scientists will find any evidence of astronomical signals in climate.
Superlative discussion!
I was following this thread last night till I packed it in around 4am EST; picked it up again an hour ago and I am still impressed with the quality of discussion. Way to go all!
My two cents, which is admittedly small in today’s currency…
Ships still follow ships whenever possible as the wake of a leading ship breaks up surface tension and depending on wind, sometimes the waves. The following ship finds it slightly easier. Any temperature checks by a following ship means sampling the mixed water for temperature.
I’m not aware of ships checking water temperature on a regular basis across their entire route. Consider, would a regular temperature check be hourly or by kilometer or perhaps some odd mixture of both? Time sailing does not translate to regular progress across the sea, nor does taking measurements by distance traveled translate to regular time metrics.
Which brings up a concern about averaging temperatures a very bizarre average. Not only are ship transits not viable for averaging based on time or distance; but many ship transits cross ocean current conveyors or even stay within a particular current for a significant length of time. How does one average many temperature points made within a warm current with temperature points taken elsewhere? Average ship collected ocean temperatures are not palatable for averaging.
“How does one average many temperature points made within a warm current with temperature points taken elsewhere? Average ship collected ocean temperatures are not palatable for averaging.”
Yes that is a legitimate concern. However, sometimes it is surprising how well SST cross-checks with other physical data. This gives some reason to believe that they are not total garbage.
http://climategrog.wordpress.com/?attachment_id=233
http://climategrog.wordpress.com/?attachment_id=219
http://climategrog.wordpress.com/?attachment_id=215
Note the last one is HadSST3 . It may give some hope that it’s not all bad and also suggests there may be either an unresolved bias or an incorrect correction around 1925 where I have added an offset to align the two series.
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Oh dear – nonsense, I am afraid.
Possibly total hull depth, but certainly not height of ships’ deck above the waterline, for those years [My guess for the1930s – 3-4 metres. OK, by the 1980s some Supertankers had deck height – in ballast – of c. 17 metres or more – but certainly not an average!!].
As Richard Verney’s several excellent posts indicate, many of the Team’s assumptions are plain wrong.
Ships have a lifetime of fifteen or twenty years [more than that for modern LNG Carriers and for cruise liners that don’t try to smash small Italian islands]; a wholesale change to ER intakes on one day in 1941 is dribbling nonsense.
I have taken ‘sea temperature’ readings on many ships. I always tried to do it the same way. We used – in the 1970s and 1980s – a standard rubber-with-brass-fittings Met Office Bucket [I was on a succession of Voluntary Observing Ships; the Met Office supplied calibrated thermometers, Stevenson screens, a digital aneroid barometer and the bucket, plus instructions].
We took readings every six hours, at the synoptic hours [06Z, 12Z, 18Z and 00Z], as instructed.
Sea temperatures: –
Go to the lowest deck.
Bucket over the lee side.
Leave it there, in the top metre or so of water for a minute, so bucket and water are similar temperatures.
Haul it up swiftly, put it in the shade, ideally off the [steel] deck, and put the thermometer into the water.
Leave for about a minute, then lift the thermometer out of the water – but only enough to read it.
Read it.
Read the temperature to the nearest tenth of a degree centigrade.
Empty the bucket into the scuppers.
Record the measurement.
Engine rooms record data at watch-end – usually every four hours – at least until unmanned engine rooms, introduced gradually from the 1960s or early 1970s [I first sailed with one in 1974]. Nowadays, some ships have continual data recording – three temperatures every minute – but as Richard Verney pointed out – that’s not Sea SURFACE temperature.
As noted, speeds vary – big container ships have averaged about 25 knots, whilst supertankers in the slow-steaming era [much of the 1980s] typically did 9-11 knots all the way round Africa, from the Oil Gulf to Europe.
Ship’s draft & trim will affect how far the bucket has to be hauled. Interestingly, our current latest-generation ships are most efficient trimmed two metres or so by the head, which looks unseamanlike – but cuts fuel consumption [when you burn 180 tonnes of fuel a day, at $700/tonne, every little helps!].
justthefactswuwt – at 4-24 pm – has a world map. I may be able to send in [but probably not post] a later Met Office map [about 2010, I think]; accessing work’s emails tomorrow . . . .
At the head of my last, I referenced his: –
“Folland et al. (1984) applied corrections to NMAT to compensate for the historical increases of the average height of ship’s decks. These rose from about 6 m before 1890 to 15 m by the 1930s and 17 m by the 1980s.
Sorry.
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richard verney says: May 25, 2013 at 5:54 pm
Your comment of 5:39pm crossed with my comment of 5:41pm.
You might be interested in my comment of 5:21pm. You will see why I consider that the data post 1950 is problematic and should not be relied upon.
E.M.Smith says: May 26, 2013 at 7:54 am
In reading the above I didn’t see much mention of the disruption of the layering caused by the passing of a ship.
Yes, synthesizing, potential biases in the Sea Surface Temperature post 1950 include:
Engine Intake Depth: varies based on ship type and size, cargo load, fuel load/consumables load, vessel trim, squat, varying ship speed, when in motion, and ocean conditions/wave heights.
Ocean Mixing: due to the measuring ship’s wake and propulsion, as well as those of other ships when traveling in convoys, or in frequently transited shipping lanes, channels and ports, varies by ship type and size, ship speed, proximity to other ships and tendency to travel in the wakes of other ships.
Measurement Location Spatial Distribution: Concentrated in shipping lanes, very limited coverage of large areas, especially in the Southern Hemisphere, Arctic and Antarctic
Thermometer Precision and Calibration: varies by thermometer type, thermometer age, thermometer calibration frequency, and diligence of the reporter
Data Reporter Diligence and Honesty: varies based on who was responsible for capturing the measurements in log book, how well they read the thermometer, how frequently they missed measurements, how they handled missed measurements, and whether they or their superiors had an incentive to manipulate the data to, justify additional heating or cooling charges to their customers, or otherwise.
Have I missed any?
Looks to me like the water’s been coolin off for the last 8 years or so. Well, 16 years of cooler atmospheric temperatures could be having some effect. But then it’s supposed to go the other way, no? Water then air? But the less active solar situation has nothing to do with it, right? Maybe we’re just coming out of the interglacial warming period for whatever indeterminate reasons, with emphasis on the word indeterminate.
richard verney says: May 25, 2013 at 5:54 pm
The number of buoys deployed in ARGO is wholly insufficient to get a proper handle on sea water temperature, and the data set is way too short. If ocean cycles are in the region of 60 years, 60 years of data would be required as a minimum.
Further, we do not know what biases may be creeping into ARGO. These are free drifting voyages. They drift with currents. Temperature is a factor in currents. because of the drfiting nature of ARGO, the potential for it to acquire a temperature bias (whether this be warm or cool) is probably substantial. Much analysis would be required to see whether such a bias is creeping in, and we are not even begiinning to acquire the data required to carry out such an assessment.
I am not going to defend Argo, but I do think that once we have 60 or so years of Argo data we’ll be in much better place to make policy decisions than we are in now.
I was a ship’s engineer 1965-1968 (instead of then still oblidged military service). Seawater motor cooling inlet temperatures were noticed every hour. But even within minutes they could change substantially when crossing sea currents.
I wonder what the value is of these measurements in pre-ARGO times, when most measurements were made within relative narrow ships routes…
There has been no mention of temperatures taken from naval vessels, but if this dataset includes those ships, then I would observe that watchstanders on naval vessels take these temperatures every hour. However, most naval surface ships that used steam (once common, but not very many, any more), had more than one engine room, and the water that came out of the condenser in the fwd engine room was put back into the sea ahead of the seawater intake for the aft engine room, so the numbers in the aft condenser should be higher than the fwd engine. Modern gas-turbine ships probably report temperature from SW cooling system intakes – not steam condensers. Also, (this is from memory) none of those readings was accurate to better than 1 degreee F, or maybe even 1C, for metric ships. Maybe not even 2F.
And then, of course, there are the submarines, but hopefully they did not use (or even see) any of that data…
I find this comparison of the global HadSST2 and 3 datasets with the Kaplan SST dataset most instructive:
http://i1172.photobucket.com/albums/r565/Keyell/HadSST2amp3vsKaplan_zpse3f47735.png
Of these three, I surely hold Kaplan as the most reliable. I base this on its near perfect stepwise fit between global and NINO3.4 SSTs during the 1948/53-76 stretch, where both the others struggle with huge divergences, but 3 to a lesser extent than 2:
http://i1172.photobucket.com/albums/r565/Keyell/Kaplansteps_zpsed9640cd.png
http://i1172.photobucket.com/albums/r565/Keyell/KapvsHad2_zps7a1c2c77.png
Whatever happened to Kaplan …?
tonyb says: May 26, 2013 at 12:10 am
As already mentioned the splitting of hairs by angels whilst they simultaneously dance on the heads of pins means the bucket data from Bottomley will do nothing to materially alter the inherent mistakes and huge margin of error in the original bucket reading.
I am not really interested in parsing down the intricacies of bucketology, more as you say, they were splitting hairs on the tips pins, while ignoring the multitude of other uncertainties and biases involved. What I am interested is that the IPCC was formed in 1988;
http://en.wikipedia.org/wiki/Intergovernmental_Panel_on_Climate_Change
and one of the first things they took on was funding Bottomley et al. to adjust the sea surface temperature record:
http://www.readcube.com/articles/10.1002/joc.3370110810
I am investigating temperature adjustments/corrections from the big picture perspective and it seems that Bottomley et al. was one of their first concerted efforts to rewrite a portion of the temperature record. I suspect that, being an early work of the IPCC, and given that it is so hard find, it might be flimsy, they might have taken liberties and won’t withstand scrutiny. Regardless, seeing as it helps form the basis for a temperature record that is being used for policy making decisions, it seems like a document that should be in the public domain…
However the met office library and archives are extremely helpful in my opinion and I use them regularly for my own research as they are situated only 15 miles from my home.
…
If the Bottomley document is in the library itself as a book or paper I can have a look at it for you next time I am there, but you would need to ascertain via email that it is physically available at either library or archive for personal viewing. The two facilities are several hundred yards apart. You would need to tell me precisely what information from the document you seek.
I’d really like to see the document in totality and have an electronic version available for public access, but if only a hard copy was available, “the second section considers the homogeneity of the ‘quality-controlled’ SST and MAT data prior to 1942. The Atlas contains the most comprehensive details of the mathematical model developed by the authors to simulate the operation of uninsulated buckets. Because of modifications and refinements to the technique a late additional table in the Atlas is extremely useful. This gives the various correction procedures used by the combinations of the authors over the period 1984-1990.”
I know that “this may seem a trivial point but different analyses of the same basic data have come to quite radically different conclusions. Newell et al. (1989), for example, conclude that there has been little warming since the mid-nineteenth century while Folland and Parker (1990) conclude that warming of about 0.4 “C has occurred. This latter result is in accord with the recent IPCC report (Folland et al., 1990).”
http://www.readcube.com/articles/10.1002/joc.3370110810
Let’s see if we can rustle up an electronic version and then I’ll get back to you in terms of a visit to the met office library.
Here’s the observations of someone who served in the USN ’87-’93 as a machinist mate who took more sea water readings then I care to think about.
-We were suppose to take readings every hour on sea water. Depending on the watch stander that may or may not have happened. Wasn’t unusual for a reading to be taken at the beginning of watch then be filled in for the rest of the hours. Some never even took a real reading for the entire watch but instead continued filling out what a previous watch stander used.
-Calibrated??? What’s that? We never calibrated our thermometers for SW injection, we just were not that concerned with their accuracy. What we needed to know was the trend, is the water getting warmer or colder? “IF” a thermometer broke it’s replacement would likely be factory calibrated but that didn’t happen very often.
-Accuracy, see calibration above. Most the thermometers had either 2 or 5 degree hash marks and close was close enough.
-Last of all is the parallax issue. We had heights ranging from 5’4″ to 6’7″, do you honestly believe we all made sure our eyes were at the proper height for reading? I’m over 6′ and would often see a 2-3 difference between what I read and what the previous watch stander read until I lowered myself down to their reading level.
My point is that pre Argo we can’t trust any of the readings to be very accurate.
Steve McIntyre:
I have served on UK merchant vessels which were part of the VOS fleet as a radio officer, sending METEO reports every 6 hours.
I now teach trainee merchant navy officers and senior serving officers in todays merchant navy.
If you have a few questions that you would like put to the deck officer lecturers about their experience with SST and engineering lecturers about engine room main sea water inlet temperature measurement, then let me know.
jeez says: May 26, 2013 at 3:57 am
It appears that the CD Rom contains these datasets.
http://iridl.ldeo.columbia.edu/SOURCES/.GOSTA/
Plus this documentation.
http://badc.nerc.ac.uk/data/gosta/atlas7help.html
I stand corrected, this looks like it;, i.e:
Here’s the warning label:
Justthefacts
If you want me to look in the met office after you’ve had a root round for information just send me an email
Tonyatclimatereasondotcom
Tonyb
Holy moly. I may have to revise my opinion about whether certain actions are physiologically impossible, much less enjoyable.
Steve Richards says: “If you have a few questions that you would like put to the deck officer lecturers about their experience with SST and engineering lecturers about engine room main sea water inlet temperature measurement, then let me know.”
Thanks Steve, one of things that bugs me about the post war adjustments made by Hadley it is their assumption (and it is no more than that ) that a significant proportion of metadata was incorrect.
This is to say , the written records from the ships log as to whether the reading was over the side bucket measurement or engine-room intake can not be regarded as correct.
There are records where this is not specified and that is a different issue. I guess what they are trying to say here is that on ships where the practice was to take outside, direct measurements, if it was cold or wet the seaman charged with the chore may prefer to slip down to the nice warm engine-room (?) rather than go out on deck.
Maybe there is some other reason for this sort of discrepancy, their reason for “correcting” the metadata is purely a statistical one : if a certain grid cell does not have what they consider to be the “right” proportion of bucket/EI readings,then someone must be cheating.
What are the chances of that sort of thing occurring in the merch’ ?
I would ask the same question of Darrin and Ferdinand in their respective services.
I expect the answers may be very different for military and merchant vessels but I would like to have your experiences and observations.
Global Ocean Surface Temperature Atlas (Gosta) M. Bottomley, C. K. Folland, J. Hsiung, R. E. Newell and D. E. Parker, Meteorological Office (Bracknell) and Massachusetts Institute of Technology, 1990. No. of Pages: iv + 20; No. of plates: 313
http://badc.nerc.ac.uk/data/gosta/intro.html#RTFToC6
I think this quote illustrates the real problem with ship’s data:
In other words the ships were taking water temperatures to figure out where the Gulf Stream and other strong currents were, and the differences in temperature were great enough that accuracy was not a real issue. Therefore the ship’s crews were not interested in measuring sea temperature accurately. All they were interested in was if they were in “Warm water” (Gulf Stream) or “Cold Water” (Not gulf Stream.)
You would be lucky if the reading were actually good to +/- 2C.
Here’s another twist on things. Many have observed the close affine relatinship between temperature and rate of change of CO2 since reliable CO2 measurements began in 1958. Some have pointed out that such a relationship is especially good using Southern hemisphere temperatures, which would appear to support the position that this is largely an oceanic phenomenon.
There is a simple physical basis for expecting such a result. CO2 is continually upwelling in tropical latitudes from frigid waters which sank at the poles centuries ago. Conversely, it is continually downwelling at the poles. Any imbalance between those two flows is modulated by temperature, leading directly to a model of the form
dCO2/dt = k*(T – Teq)
CO2 = atmospheric CO2 concentration
k = coupling factor representing the amount the imbalance changes per degC
T = representative current surface temperature
Teq = an equilibrium temperature defining at what point CO2 increases or decreases
On objection I have gotten from those who will seek any excuse to ignore what is right before their eyes is that the relationship does not work before the modern era of CO2 measurements, i.e., that if you use modern values for “k” and “Teq” and integrate the temperature backwards to the turn of the 20th century, you get too low a result for CO2 levels at that time.
I have responded that
A) CO2 measurements prior to 1958 are problematic – that is why MLO was set up. If the data from ice cores were trustworthy, why would they have needed anything else?
B) the values for “k” and “Teq” are not necessarily constant – in fact, it is remarkable that they have been so apparently steady in the modern era since 1958. So, I showed that, if you simply introduce a step change in “Teq” at or around 1945, you can easily match up the CO2 at the turn of the century.
The question is essentially moot, because the relationship holds in the modern era and, since that is the era in which the majority of the increase in CO2 took place, it falsifies the hypothesis that humans have been driving the CO2 concentration in that era, and therefore humans are not responsible at least for the majority of the observed increase.
In any case, if the magenta line in the graph above is actually considered accurate, I would not need a step change in “Teq” – there is actually a step change in T matching what was observed in sea surface temperatures already. And, the step occurred… wait for it… roughly about 1945.
Moderator – my apologies. If you could put a slash_a at the end of ‘…introduce a step change in “Teq” at or around 1945, you can easily match up the CO2 at the turn of the century.’ above, the text would read better.
REPLY: no, sorry, your instructions are too confusing, I have no idea what “slash_a” is. – live with it – Anthony