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.
http://i56.tinypic.com/308fjar.jpg
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.”
http://research.metoffice.gov.uk/research/nwp/publications/mosac/MOSAC_15.10.pdf
SOURCE
The HADSST2 and HADISST data used in this post are available through the KNMI Climate Explorer:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
Posted by Bob Tisdale at 6:46 PM
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
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 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.
http://a.imageshack.us/img832/3174/newesthadsst3.png
There is also some discussion in this paper.
https://abstracts.congrex.com/scripts/jmevent/abstracts/FCXNL-09A02a-1662927-1-cwp2a15.pdf
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:
http://research.metoffice.gov.uk/research/nwp/publications/mosac/MOSAC_15.10.pdf
AND:
http://research.metoffice.gov.uk/research/nwp/publications/mosac/MOHCCPWorkPlan_FY10-12.pdf
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)
http://www.vukcevic.talktalk.net/GWDa.htm
into what I observed as un-natural discontinuity.
What you suggest is an interesting idea, perhaps you could elaborate, time permiting.
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;
http://hadobs.metoffice.com/hadcet/
We also have the much older (and curiously underused) CET records which enables us to take a further step back in time to 1660.
http://homepage.ntlworld.com/jdrake/Questioning_Climate/_sgg/m2_1.htm
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)
http://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/
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…
tonyb
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.
tonyb says:
November 27, 2010 at 7:48 am
Thankyou. Very informative
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?
Bill Illis posted:
http://a.imageshack.us/img832/3174/newesthadsst3.png
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.
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?
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.
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.
tonyb.
“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.”
http://www.guardian.co.uk/environment/2010/nov/25/2010-joint-hottest-year-global-warming
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]
@Bob 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.
Bob, I hope you will be keeping an eye on the following.
Going thru :
http://research.metoffice.gov.uk/research/nwp/publications/mosac/MOSAC_15.10.pdf
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!
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.
Regards
This is an interesting article about the Argo floats which covers a lot of the issues raised here: http://earthobservatory.nasa.gov/Features/OceanCooling/
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.
Sandy.
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.
vukcevic, the X pattern 1920-1940 in your seasonal CET graph is key. More work in the in-box…
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’
http://www.bbc.co.uk/news/uk-11841368
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”.
Paul Vaughan says: November 28, 2010 at 5:45 am
…………….
I looked at that one few times with no conclusion.
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.)
Related:
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…)
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. enquiries@metoffice.gov.uk
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.
regards.