Does Hadley Centre Sea Surface Temperature Data (HADSST2) Underestimate Recent Warming?

Guest post by Bob Tisdale

In advance of the UN negotiations next week in Cancun, the press and blogs today have included numerous elaborations on the UK Met Office press release Scientific evidence is Met Office focus at Cancun. The Australian article “Global temperature rises may be underestimated due to errors, Met Office study says” by Ben Webster includes the following statement, “The long-term rate of global warming was about 0.16C a decade in the 1970s, 1980s and 1990s but it slowed in the past 10 years to between 0.05C and 0.13C, depending on which of three major temperature records is used. The Met Office said that changes in the way ocean temperatures were measured had resulted in an under-estimate of about 0.03C in recent years.”

But what the Met Office fails to mention is that the dataset being discussed in the press release, their HADSST2 data, which is the sea surface temperature dataset used in their HADCRUT3 and HADCRUT3v global temperature products, is biased upwards by almost 0.12 deg C after 1998 due to a change in source data in 1998. I’ve illustrated and discussed this bias in two previous posts: Met Office Prediction: “Climate could warm to record levels in 2010” and The Step Change in HADSST Data After the 1997/98 El Nino.

The new source Sea Surface Temperature data was not fully consistent with the source dataset the Hadley Centre used prior to 1998. So when they merged the two datasets, the Hadley Centre failed to account for the inconsistency and created an upward bias in their HADSST2 data. This bias is easily seen when the other Hadley Centre sea surface temperature dataset, HADISST, is subtracted from the HADSST2 data, Figure 1. Note that the HADISST has relied primarily on satellite-based measurements since 1982, but the HADSST2 data is based on buoy and ship readings. The upward step is approximately 0.12 deg C. The bias created by the change in measurement methods over the past decade that was reported on in The Australian would only offset a portion of that shift.

Figure 1

Hopefully, when the Hadley Centre finally releases its updated Sea Surface Temperature dataset (HADSST3) they will eliminate the upward step. And for those interested, here’s a link to a Met Office Scientific Advisory Committee (MOSAC) publication, “Climate monitoring and attribution,” that provides an overview of the upcoming HADSST3 and HADISST2 datasets. Refer to page 3 under the heading of “3. Progress in development of marine datasets.”


The HADSST2 and HADISST data used in this post are available through the KNMI Climate Explorer:

Posted by Bob Tisdale at 6:46 PM

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November 26, 2010 7:11 pm

Thank Bob
I sincerely hope that the scientists without a real voice in Australia, will finally be given equal reporting in the Australian Media. Something that is sorely lacking. There is little balance at all. May your voices be heard and well understood above the political clamour.

Tom in Texas
November 26, 2010 8:01 pm

“…eliminate the upward step”
Bob, let me guess how they will do this:
Lower the temps before 1998.
Raise the temps after 1998.
Result: Nice smooth “robust” upward trend, with no upward step.

Sean McHugh
November 26, 2010 8:17 pm

How many more, “It’s word than we thought” cries can they credibly have?

David A. Evans
November 26, 2010 8:27 pm

Tom in Texas says:
November 26, 2010 at 8:01 pm
Getting hard not to be cynical isn’t it? I know, I feel the same way.

November 26, 2010 9:47 pm

Professor David Karoly from The University of Melbourne was quoted in the Shepparton News (Victoria, Australia) on Nov 26 2010 as saying “Twenty-first century anthropogenic carbon dioxide emissions will contribute to warming and sea level rise for more than a millennium, due to the long timwscales required for removal of this gas”.
“He emphasised the fact that some 97 percent of the world’s climate scientists agreed with IPCC findings that, among many other things, suggested it was very likely that hot extremes, heat waves, and heavy precipitation events would continue to become more frequent.”
Liar liar pants on fire.
David Karoly is definitely off my christmas card list now.

John F. Hultquist
November 26, 2010 10:23 pm

Temperature. It seemed a rather simple concept in 9th grade science class.

November 26, 2010 10:36 pm

I’m sure all this means something, but frankly it’s gone right over my head. Can some please explain the issue and the what the above means, vis a vis the Met claims, in simple english for us who only have 10 watt bulbs between our ears.

November 26, 2010 10:57 pm

I’m going to turn on the weather channel now and watch all the snow storms. Really I am. I hear the pacific northwest is going to get another blast of the white stuff this weekend. Seattle isn’t used to the frozen variety of precipitation.

November 26, 2010 11:41 pm

Here is, how HadSST3 is being prepared:
From: Tom Wigley
To: Phil Jones
Subject: Re: 1940s
Date: Sep 28, 2009
Cc: Ben Santer
Here are some speculations on correcting SSTs to partly
explain the 1940s warming blip.
If you look at the attached plot you will see that the
land also shows the 1940s blip (as I’m sure you know).
So, if we could reduce the ocean blip by, say, 0.15 degC,
then this would be significant for the global mean — but
we’d still have to explain the land blip.

It would be good to remove at least part of the 1940s blip,
but we are still left with “why the blip”.
I suppose they will eliminate the 1940 blip and considering the recent findings underestimating the global T, they will introduce another 0.12 °C into the late record.
We cannot expect from these people serious data. Canada recently dissolved their climate research center. Way to go!

November 27, 2010 12:36 am

The simple form is that the news is saying “It could be warmer than we thought because we made an error” while at the same time they are ignoring a larger error that makes it really cooler than they said in the first place. So the “warmers” are basically playing a game of ‘selective listening’ to potential errors.
It’s been a record early open at Vail Ski Resorts:
Opened in the “November Teens” and with pre-Thanksgiving Skiing…
Yeah, a lot more snow on the way. It’s going to be this way for a few decades, so get used to it. The new cold PDO phase and all that…

P Wilson
November 27, 2010 12:54 am

Confused says:
November 26, 2010 at 10:36 pm
Hadley are splicing 2 sst data sets – mainly satellite data, pre 1998, and ships/buoys together, post 1998 that give different trends and different temperatures from pre-1998 data methods. They didn’t correct the data post 1998 that gives an upward bias to SST’s

John Marshall
November 27, 2010 1:25 am

And yesterday morning on BBC Radio 4 news it was reported that the Met Office have said that 2010 is on course to be the second warmest year on record. Considering winter2010 in the NH and winter 2010 in the SH which both broke cold records of one sort or another and the UK summer was not much to write home about one wonders which planet do these people live on.
Temperature readings of 0.03C are inside the error bands so how does this figure have any relevance? The Met. Office still insist on smoothing time series which is a serious error in statistical circles!

Ian Blanchard
November 27, 2010 1:37 am

And in the meantime, the Met Office are announcing that 2010 is the hottest year ever (or at least not statistically different from 1998) – even though we are still a few weeks from the end of the year, and current temperatures are low (AQUA ch 5).
Irony is, the UK is suffering one of its coldest and snowiest ends to November in my lifetime, and is forecast to stay cold for up to a couple of weeks.
Is the HadSST data used in the construction of HadCRU3?

November 27, 2010 2:04 am

Bob that as an interesting discovery.
Some time ago I also found similar non-natural discontinuity between pre- and post-‘accurate instrument’ CET records.
If this discontinuity indeed is an artefact of data standardisation before and after accurate measurements were available, then there is a serious consequence for the CETs trend, as I have shown here

Martin Brumby
November 27, 2010 2:31 am

I wonder if the Met Office has just stopped caring about their credibility.
Even if their “extra 0.03ºC” ocean temperature was absolutely correct and they could measure to this accuracy, we are supposed to worry about 0.03ºC? Why??
These comedians know full well that the incompetent and venal politicians will latch on to their pronouncements and use them as justification of more hikes in tax and energy prices.
Sooner or later they will look out of the windows of their ivory tower and see the peasants massing with pitchforks and flaming torches. It will get much hotter for the Met Office scientists than any 0.03ºC!

November 27, 2010 2:32 am

Well would you ‘Adam and Eve’ it.
Just before it was beginning to look as though this year (Strong El Nino year) isn’t going to be any warmer than 1998 (The previous strong El Nino year) and therefore NOT the warmest year on record, those clever people at the Met Office have discovered yet another ‘trick’ to adjust 2010 upwards… and just in time for Cancun.

November 27, 2010 2:52 am

Confused says: “Can some please explain the issue and the what the above means…”
The Met Office claims that sea surface temperatures measured by buoys are lower than those measured by ships, and in the past 10 years, more buoys have been used to measure global sea surface temperatures. The additional use of buoys has caused them to report lower-than-actual sea surface temperature anomalies in their global surface temperature product, or so they say. Actually, I have no basis to doubt or contradict this. In fact, there are a number of papers that discuss this problem.
First, there are a number of Sea Surface Temperature datasets available for use in the global temperature products. The Hadley Centre, GISS, and NCDC all use different ones. Two of these datasets, the ones discussed in the post, are available from the Hadley Centre. The Met Office claim about buoy bias was for the dataset used in the Hadley Centre’s product, HADSST2, and it is based only on ship and buoy measurements. The other Hadley SST product has been based on satellite measurements since 1982. The following is a graph of those two global datasets from 1982 to present.
A couple of years ago I noted that there was a curious difference between the Hadley Centre’s HADSST2 dataset and all other Sea Surface Temperature datasets. The HADSST2 data shifts up considerably during and after the spike in 1997/98. The spike in 1997/98 is due to an El Niño event and it masks the difference between the HADSST2 data and the others. Notice how that HADSST2 anomalies are below the HADISST data before the 1997/98 El Niño but are above it afterwards. The shift is easier to see if the HADISST data is shifted down 0.06 deg.
In the graph I created for the post, Figure 1, I subtracted the HADISST data from the HADSST2 data to show the timing of the shift.
About 2 years ago, I discovered that the Hadley Centre changed sources for their HADSST2 data in 1998, while the sources for the other SST datasets remained constant. The supplier of the two datasets used by the Hadley Centre cautioned that there were inconsistencies between the two datasets, and it appears as though the Hadley Centre failed to account for those inconsistencies.
My point in this post was, before the Met Office can claim any importance from the bias created by the transition from ship measurements to buoys, they need to fix the upward shift created when they merged two incompatible SST datasets. The shift created by the use of the two incompatible datsets is considerably more than any bias caused by the change in measurement type.

November 27, 2010 2:53 am

P Wilson says: “Hadley are splicing 2 sst data sets – mainly satellite data, pre 1998, and ships/buoys together, post 1998 that give different trends and different temperatures from pre-1998 data methods. They didn’t correct the data post 1998 that gives an upward bias to SST’s”
Nope. Refer to my reply to Confused above.

November 27, 2010 2:58 am

The credibility of the Met Office in the UK is no longer an issue – it has none. I rubbed my eyes when I read earlier this week that 2010 would be the warmest year yet. Not in the bit of London where I live, it won’t. My outdoor max/min thermometers from which I keep a record, tell me its consistently below last year’s temps for this time of year.
The nonsense reason given by the head of the Met Ofice for this silliness will no doubt see the old temp records adjusted downward.

November 27, 2010 3:00 am

Nicley picked up!:
Juraj V. says:
November 26, 2010 at 11:41 pm
Here is, how HadSST3 is being prepared:
From: Tom Wigley
To: Phil Jones
Subject: Re: 1940s
Date: Sep 28, 2009
Cc: Ben Santer

November 27, 2010 3:20 am

did you notify Hadley about this error ?
If they really choose to ignore that step function, I wonder what is going on.

P. Solar
November 27, 2010 3:32 am

This is VERY interesting. Only two days ago I was looking at the Met. Office graph and noted the despite the short term ups and downs it seems fairly level before the el Nino event and equally flat after.
I had concluded that there had been some permanent effect and the temperatures had never recovered to the pre 1998 levels. That there was a step change around that time. I conjectured this may be similar to the step change in 1976 in the PDO cycle.
Basically I was HAD by Hadley !
Kudos many thanks and to Bob Tisdale for bringing this to light. I shall sleep a wiser man tonight.

November 27, 2010 3:41 am

I have just sent an e-mail message to the Met Office complaining about inaccurate weather forecasts. Yesterday I had to make a car journey from South Wales to Exeter (where, by coincidence, the Met Office is based). On Thursday night the weather forecasts on television were predicting snow for Scotland and parts of eastern England but not for South Wales and southwest England.
On Friday morning I checked the Met Office website before setting out but once again no snow was predicted for South Wales or southwest England. On the way back I had only got just over 30 miles from Exeter when a blizzard started. Conditions were even worse in South Wales with snow causing a 25 mile queue from the Severn Bridge toll booths onwards.
Now I don’t expect weather forecasts to be accurate all the time, but you would think the Met Office could predict blizzards over a large area several hours in advance. Only a couple of weeks ago the Met Office got a lot of criticism from people in Cornwall for failing to predict floods. (Cornwall is not far from the Met Office base in Exeter either).
Perhaps UK tax payers would prefer the Met Office to spend less of their money on global warming propaganda (sorry “research”) and more on its day job of weather forecasting.
If the present lot had been in charge of the Met Office in June 1944 they would have got the weather forecast for D-Day just as wrong as the Germans did and the landings would have been postponed and, since it would not have been possible to postpone them for very long, the Allies would have had to go ahead in much worse conditions, possibly with tragic consequences.
Three other great invasions failed largely due to the weather; the Mongol invasions of Japan in 1274 and 1281 failed when their fleets were destroyed by the “Divine Wind” or Kamikazi (hence the name of the Japanese suicide attacks on US and other Allied ships in World War II), and the Spanish Armada was greatly damaged by storms in 1588. That was also attributed to divine intervention. To celebrate the failure of the Armada the English made a commemorative medal saying ‘He blew with His winds, and they were scattered’.
If the Japanese and Mongols, and the English and Spanish, of those periods had thought like we do today the failure of those invasions would have been attributed to “climate change”!

Reply to  Roy
November 27, 2010 3:52 am

perhaps we also have divine intervention now that we have become too upity as a species, imagining that we have an undue influence on the world’s climate 😉
Actually we seem to have more than our fare share of forecasting ability in the UK. Not only do we have the Met Office, but Reading is home to the European Centre for Medium-Range Weather Forecasts, on whose weather modelling data much of Europe’s forecasting is based (e.g. here).

November 27, 2010 4:04 am

Manfred says: “did you notify Hadley about this error ?”

mike g
November 27, 2010 5:18 am

Maybe buoys are more accurate than ships and they need to lower their ship based measurements to match the buoys? Notwithstanding this other really convenient failure to calibrate that Bob is pointing out.
After all, the buoys are scientific instruments design specifically to measure temperature as accurately as possible. Ships are not.
If they had any integrity whatsoever, why use the non-scientific instrument over the specially designed scientific instrument, just because doing so happens to bias the temperatures the way you need them to be biased?

Golf Charley
November 27, 2010 6:13 am

As 97% of climate scientists support the AGW theory, and governments around the world are having to tighten their budgets, I would suggest cutting climate change research budgets by 97%.
This will lead to a temporary rise in temperatures, as thousands of research papers are burned, starting with those by authors such as Mann, Jones et al

Paul Vaughan
November 27, 2010 6:29 am

vukcevic, your CET summer minus winter insights appear conditionally related to solar cycle acceleration (a.k.a. rate of change of solar cycle length). This could be a substantial clue for those researching the origins of the North American Dirty 30s Dust Bowl Drought.

Bill Illis
November 27, 2010 6:35 am

I don’t think they are as concerned with the 1998 step change as much as with the step change in 1946 and adjusting the record so that it shows greater and more continuous warming.
Since I read the email about the new HadSST3, I’ve been watching what is going on. This latest paper (which doesn’t seem to be available yet and was rejected by another journal previously) is just one in a series that is being used to pave the way for adjusting the record.
The major adjustments will be in these two papers which are in preparation.
Kennedy J.J., Rayner, N.A., Smith, R.O., Saunby, M. and Parker, D.E. (2010). Reassessing biases and other uncertainties in sea-surface temperature observations since 1850 part 1: measurement and sampling errors. in preparation – part 2: biases and homogenisation. in preparation
This is what the new HadSST3 will look like – in the top panel, the green line is the new HadSST3 and the red line is the current HadSST2.
There is also some discussion in this paper.

November 27, 2010 7:26 am

Bill Illis says: “This is what the new HadSST3 will look like – in the top panel, the green line is the new HadSST3 and the red line is the current HadSST2”
So they’ve reduced the (Folland) correction from the raw ICOADS data before 1945 by shifting the back data down again. (A wholesale shift in Southern Hemisphere data maybe?) It also looks like they decreased the trend after the 1950s, pivotting the data down on an axis around 1950. Curious.
The following links should give an idea of the changes and their timing next year:

November 27, 2010 7:29 am

Paul Vaughan says:
November 27, 2010 at 6:29 am
vukcevic, your CET summer minus winter insights appear conditionally related to solar cycle acceleration (a.k.a. rate of change of solar cycle length). This could be a substantial clue for those researching the origins of the North American Dirty 30s Dust Bowl Drought.
I only presented it as a ‘conditional’ exploration (with lot of if-s in there)
into what I observed as un-natural discontinuity.
What you suggest is an interesting idea, perhaps you could elaborate, time permiting.

November 27, 2010 7:48 am

Meanwhile in the REAL world UK temperatures have been plummeting in recent years. (this doesn’t constitute a ‘trend’) This can be seen in the 1772 Central England Temperature (CET) record , which shows anomalies (deviations from a given average) up to this month;
We also have the much older (and curiously underused) CET records which enables us to take a further step back in time to 1660.
From here we can see many peaks and troughs and that our temperature today is around that of 1730-the middle of the Little Ice Age. Temperatures have been rising throughout the instrumental record-long befoe any possible influences from Man.
Creating a ‘global average ‘ temperature is a curious thing to do as it disguises the hundreds of locations worldwide that have been cooling for at least thirty years (a statistically meaningful period)
Listening to the UK Farming today programnmes are instructive. Just in the last few weeks we have a farmer-encouraged by the govt-who planted Apricot trees 10 years ago and is now grubbing them up as they don’t ripen, and just this morning someone saying we don’t get the hot dry summers we used to have which impacts on quality of vegetables.
Of course they’re ‘anecdotal’ rather than robust information from a computer lab so they don’t count.
Verity: Having seen a lot of studies from warmists recently taking the last 30 years as a trend, I’m beginning to regret that we were so concerned that we’d be seen as cherry picking with our own study. What’s good for the goose…

P Wilson
November 27, 2010 8:18 am

Bob Tisdale says:
I was reasoning with this when I read your link to the Australian Post – since buoys have a tenfold increase during the period in question, and show cooler temps than ships. It seemed incredible that they had the idea to up-bias these temperatures if they are supposed to be more accurate.

P Wilson
November 27, 2010 8:19 am

tonyb says:
November 27, 2010 at 7:48 am
Thankyou. Very informative

Werner Brozek
November 27, 2010 9:08 am

P.S. I posted this earlier at Dr. Spencer’s site, but it seems relevant here as well.
Hello Ray,
I recently read something very interesting about the GISS data. Apparently, for some reason, their older numbers get adjusted downwards and this makes the later numbers higher by comparison and thereby proves global warming is happening. Could something similar have happened to the Hadcrut data? If that were the case, the average numbers from 1961 to 1990 could have been 0.00 at one time, but later adjustments made the average negative for every month. Would it be possible to find a Hadcrut data set from 1990 to see if this adjustment happened? Or do they have another explanation why all those average numbers are now negative?

Paul Vaughan
November 27, 2010 9:33 am

Bill Illis posted:
These characters clearly do not pay attention to EOP (Earth orientation parameters) and the evolution of seasonal patterns in geomagnetic aa index. Worse than that, it’s like they don’t realize that clouds affect insolation – and that there is a relationship between wind & clouds. It is the responsibility of sensible people to find an efficient way to arrest the errant behavior of these vandals.

Peter Dunford
November 27, 2010 9:35 am

Am I right in thinking that the buoys are more accurate and reliable than ship based measurements?
If so, greater reliance on buoys and fewer ship based measurements reducing the temperatures means that the older temperature measurements are biased too high, not that the recent ones are biased too low. Surely the older temps should be massaged down not the newer ones up?

richard verney
November 27, 2010 11:00 am

It seems to me that the Met Office and CRU do not understand how ship’s data is taken. Sea water temperature reported by ships is taken from the sea water drawn for cooling the engine. Where this is drawn from depends upon the design and configuration of the ship and whether the ship is proceeding in ballast or is laden. Ships try and avoid lengthy ballast voyages since these are not revenue earning legs. With a laden ship, the sea water drawn for cooling is drawn about 10m below the surface (could be anywhere between say 7m and 13m but about 10m is typical).
What does this mean? It means that ships are measuring sea temperature at a depth of about 10m whereas Buoys measure sea temperature at a depth of about 1m. Generally, the greater the depth, the cooler the water. It follows from this (ie., the depth differential) that one would expect ship data to record a lower temperature (not a higher temperature) when compared to the similar measurement taken by Buoys. This means that in order to make a like for like comparison, one should either adjust the Buoy temperature downwards, or the ship’s temperature upwards. There is no case for adjusting the Buoy temperature upwards since this further exacerbates the difference between the depth at which the data is taken.
Further, a not insignificant number of ships may have a tendancy to deliberately under record the sea temperature. Many ships carry liquid cargoes that need to be heated (various chemicals, palm oils, veg oils etc). In simple terms, the ship owner gets paid for heating these cargoes. It is therefore in the ship’s interest to downward record sea temperature thereby enabling the ship owner to claim that he is heating the cargo when in fact he may not be heating the cargo given the warmth of tropical seas. I am not saying that this practice is wide spread but merely point out that if anything the temperatures reported by ships has a tendancy to be lower than the temperature truly encountered.
The proposed adjustment by CRU and the Met office is completely wrong.

November 27, 2010 11:21 am

Richard Verney
As you observe, buoys and ship measurements are apples and oranges. Going further back we then had the ‘bucket’ method adding in a further fruit to the equation, this time bananas. Bearing in mind the extreme paucity of the data AND the manner in which it is collected SST’s are a complete waste of time as regards being able to draw any inference of temperature change over an extended period.

November 27, 2010 11:24 am

“I think it’s too close to call. Based on these numbers it’ll be second, but it depends on how warm November and December are,” said Dr Phil Jones, director of the Climatic Research Unit (CRU), at the University of East Anglia, which says 1998 was the record year so far.”
Why wait till the end of the year Phil? Why not do what you did in 1995?
From the climategate e-mails:
GEOFF JENKINS (UK MET OFFICE) TO JONES (Nov 22, 1996): “Remember all the fun we had last year over 1995 global temperatures, with early release of information (via Oz), ‘inventing’ the December monthly value, letters to Nature etc etc? I think we should have a cunning plan about what to do this year, simply to avoid a lot of wasted time….
“We feed this selectively to Nick Nuttall [Executive Director of UNEP] (who has had this in the past and seems now to expect special treatment) so that he can write an article for the silly season. We could also give this to Neville Nicholls [IPCC lead author and Australian Met Bureau employee]??” [0848679780.txt]

November 27, 2010 11:48 am

Tisdale, thanks for clearing it up.
WRT “The Met Office claims that sea surface temperatures measured by buoys are lower than those measured by ships, and in the past 10 years, more buoys have been used to measure global sea surface temperatures.”
On what basis are they able to make these claims? Seems to me they need some other standard by which to make this comparison for otherwise, it could be that temps measured by the ships are too warm. Nevertheless, as usual they always find adjustments that seem to raise temps.

November 27, 2010 12:09 pm

Bob, I hope you will be keeping an eye on the following.
Going thru :
I found the following:
“Our sea ice analysis for HadISST2 has been completely reassessed based on new data sources and new approaches for homogenisation of the record.”
“New approaches to homogenisation of the record”! From records I’ve seen in Oz where this is done it comes down to nothing more than raising temps at a later time and decreasing temps earlier in the record.
And further:
“The uncertainty in the bias adjustments is comparable to, or greater, than the other uncertainties during the period 1940 to 2006, suggesting that a simple bracketing of all previous analyses of sea-surface temperature change significantly underestimates the inherent uncertainties.
The data set will be presented as a set of ~100 interchangeable realisations which together span the range of uncertainty. The aim is to make it much easier for users to incorporate our estimates of observational uncertainties in their analyses.”
“100 interchangeable realisations” Goodness me, not more computer stuff using Monte-Carlo generated scenarios. What parameters and ranges of these parameters will they be “inserting” into their playstations for this “analysis”? Perhaps we should ask them!

November 27, 2010 12:55 pm

Confused says: “On what basis are they able to make these claims?”
Parts of the globe have both ship and buoy measurements and it’s simply a direct comparison. The historical record is primarily made up of ship-based measurements (inlets and buckets), so lower measurements from buoys (even if they are more accurate) will appear to bias toward cool readings. Apparently, it’s easier to “correct” the measurement technology with the fewer number of readings.

November 27, 2010 1:35 pm

This is an interesting article about the Argo floats which covers a lot of the issues raised here:

November 27, 2010 1:48 pm

It’s always struck me as odd that a system of measurements based on people throwing a bucket on a rope over the side of a ship and taking water from somewhere on the way up (has there been a study on where exactly on where in the ocean the water in the bucket comes from?) and then measured by a thermometer which is calibrated exactly how and when, and is to a standard design or not. Is considered more accurate that measurements taken on bouys built to a standard design and presumably calibrated to the same standard.
As my dad used to say “seems they are doing it a**e about face” to me.

November 27, 2010 4:50 pm

FrankK says: “Goodness me, not more computer stuff using Monte-Carlo generated scenarios. What parameters and ranges of these parameters will they be “inserting” into their playstations for this “analysis”? Perhaps we should ask them!”
It would have to be you to ask the questions, since all I know about Monte Carlo scenarios has to do with Formula 1. (That is, always qualify first, cause it’s hard to pass.) Seriously, they must also be preparing a “standard” dataset for use in their new HADCRUT4 product.

Paul Vaughan
November 28, 2010 5:45 am

vukcevic, the X pattern 1920-1940 in your seasonal CET graph is key. More work in the in-box…

November 28, 2010 11:57 am

There is an interesting article at the BBC website about the Met Office’s claim that 2010 will be the warmest or second warmest year on record.
Met Office says 2010 ‘among hottest on record’
In the past the BBC has tended to reflect the “consensus” view on global warming in an uncritical way. However, after quoting the comments of Dr Vicky Pope, head of climate science advice at the Met Office, Roger Harrabin (the BBC’s environment analyst) wrote:
“There is a question over how many times the Met Office has forecast a record previously. Dr Pope said they had not done so from her recollection.”
“But a Met Office press release shows a forecast that 2007 would probably beat 1998. And a BBC report implies that they made the same prediction for the other El Nino year of 2003.”
Perhaps Dr Pope has never heard of the story of the boy who cried “wolf”.

November 28, 2010 12:26 pm

Paul Vaughan says: November 28, 2010 at 5:45 am
I looked at that one few times with no conclusion.

Paul Vaughan
November 28, 2010 2:02 pm

vukcevic, it has to do with the evolution of seasonal SOI anomalies. The SOI summer integral crossed the SOI winter integral during the interval ~1920-1940. My guess is that Corbyn has already been down this trail. The sun appears to have caused a rotation of the peak SOI anomalies inside of the year during the early 20th century. (Bob Tisdale please take note.)
As I have noted in recent discussions, there is a phase reversal in the 50s. Earlier I estimated that it occurred ~1952, but today’s results suggest that it may have been a few years later. I originally detected the reversal by looking at interannual NPI in relation to interannual AO & geomagnetic aa index. (Note: Interannual TMin for my area works as well as interannual NPI.) I will need to explore further to understand what seems to have been a major change in the nature of circulation (which shows up in SOI, NPI, CET, LOD, the Southern Ocean, the Southeast Pacific, & Antarctic ice specific mass…)

P. Solar
December 1, 2010 2:15 am

Brief description of the data
The SST data are taken from the Met Office Marine Data Bank (MDB), which from 1982 onwards also includes data received through the Global Telecommunications System (GTS). In order to enhance data coverage, monthly median SSTs for 1871-1995 from the Comprehensive Ocean-Atmosphere Data Set (COADS) (now ICOADS) were also used where there were no MDB data. The sea ice data are taken from a variety of sources including digitized sea ice charts and passive microwave retrievals.
HadISST1 temperatures are reconstructed using a two stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic, and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration.

Just reading that lot makes my head spin. Plenty of room for some selective “adjustments” in there.
Bob , you seem to have some clearly demonstrable error in merging the two SST data sets . Can I suggest you do email this to the met office.
They have a policy of replying to every enquiry and do eventually get back (if you remind them).
It’s worth making sure that they realise we are watching and verifying their work and this sort of slight of hand does not go unnoticed.

P. Solar
December 1, 2010 4:22 am

MikeA says:
November 27, 2010 at 1:35 pm
“This is an interesting article about the Argo floats which covers a lot of the issues raised here:
Thanks, that’s an interesting article which details how group think operates, although it carefully skips over what “corrections” were made. In the references , one of the
papers in which Willis was a co-author stands out by not being a link, just a text citation. It’s oldly one of the few that is actually available and not by behind a GRL paywall.
From the abtract of this paper:
Deep reaching XBTs have a different fall-rate
history than shallow XBTs. Fall-rates were fastest in the early 1970s, reached a
minimum between 1975-1985, reached another maximum in the late 1980s and early
1990s and have been declining since.
So the “correction” to help the real data fit the models is based on frigging the fall rate of the ocean temperature probes. These probes “apparently” slow down and speed up in some as yet unidentified multidecadal fashion which is :
” likely associated with small manufacturing changes”
Even after beating the data into submission:
Catia Domingues , CSIRO says “For the most recent years [2003-2007], the sea level budget once again does not close. Our team is still working on that problem.”
Looks like the pesky XBTs are speeding up again !

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