Home > analysis, Datasets, temperature > Met Office, HadSST3, CRUTEM3, HadCRUT3, questions over gridded coverage

Met Office, HadSST3, CRUTEM3, HadCRUT3, questions over gridded coverage

Image

[update: I used an incorrect mix of datasets, see Talkshop thread here. Corrected PDF and now expanded to include HadCRUT4.

corrected PDF bundled in .zip (9.5MB) linked here HadCRUT3 and here  HadCRUT4]

The UK Met Office / Hadley Centre (Met Office) / Climatic Research Unit (UEA) construct and publish global time series for temperature based on published 5 degree gridded. How this is derived from land meteorological station readings and ship board for sea surface temperature is unclear. The gridded to eg. global is a simple (cosine) weighted average which takes into account the variable area of a linear grid representing a sphere.

I have put together maps showing the data counts for decades over a world shore outline. These are provided as vector plots (master work), PDF, or for casual looks, PNG. The results are disturbing and particularly in the light of the Met Office producing 100 different versions of HadSST3. “Each of the following files is a zip archive containing ten realisations of the HadSST3 data set. There are 100 realisations in total.”

Do I detect obfuscation, flapping for distraction?

Image

 

Image left is the cell over the majority of France, dates 1950..1959. Black squiggle is coastline, red squiggle national border. HadSST3 has 60 months of data. How exactly is the sea temperature used?

 

 

Image

Here is another, majority of area is land, not sea.

The situation has improved with time, earlier on there is what looks like highly questionable instances.

 

 

I have a database here containing gridded datasets in a common format. An extract from any grid cell can be done, time series. Given the amount of code involved in this whole work treat me as unreliable.

Sanity check

An area of Europe was selected for time series extraction where this includes an abnormal weather event. See http://tallbloke.wordpress.com/2014/09/16/the-snowfall-of-1956/comment-page-1

area-desig

area-triplet

 

Plots of grid counts

Master file is the PDF, PNG is only for those who need to use an image, less legible, use save to file. File sizes have been minimised: PDF about 600kB, PNG (3175 x 2246) about 500kB. Full sheet will just print legibly on A3 paper.
With PDF you are expected to use magnify as required.

[update: corrected PDF bundled in .zip (9.5MB) linked here HadCRUT3 and here  HadCRUT4]

1850..1859 PDF PNG
1860..1869 PDF PNG
1870..1879 PDF PNG
1880..1889 PDF PNG
1890..1899 PDF PNG
1900..1909 PDF PNG
1910..1919 PDF PNG
1920..1929 PDF PNG
1930..1939 PDF PNG
1940..1949 PDF PNG
1950..1959 PDF PNG
1960..1969 PDF PNG
1970..1979 PDF PNG
1980..1989 PDF PNG
1990..1999 PDF PNG
2000..2009 PDF PNG
2010..2013 PDF PNG

The last decade is short, 2010..2013, see notes.

Conclusions

There isn’t one. This work is informational where I hope others will step in.

Within reason I can extract data and make it available. The sheer size of data should be kept in mind. there are >2,500 grid cells.

Notes

The cutoff at the end of 2013 is pragmatic. At the time of writing the three underlying datasets finish at slightly different dates during 2014. Omission is the easy option, has no material effect on the result.
===
Data providers
HadCRUT3:- Met Office
HadSST3:- Met Office
CRUTEM3:- Met Office
===
Climatic Reserch Unit page on temperature datasets
===
Images are marked copyright to enable copying, otherwise the situation is in legal limbo which stops strict usage.
===
Coastal vector data from NOAA GEODAS
===
The resolution and colour usage in the plots is a compromise. I don’t like visually hitting people in the face, technical work where function comes first. The figures are low key so the shore outline shows through. If one is not legible for PDF magnify more.

Post by Tim

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Categories: analysis, Datasets, temperature
  1. September 21, 2014 at 17:35

    The data has been updated, see article. My mistake.

    I hope this causes no trouble for anyone.

  2. suricat
    October 4, 2014 at 00:27

    Whatever the ‘update’, the ‘resolution’ is still ‘without definition’!

    Ocean surface and land surface invoke different atmospheric responses to insolation. The most obvious of these is the ‘latent response’ from ocean surface and ‘temperature response’ from land surface. It’s dependant upon the ‘attractor’ that can more easily absorb the energy from Sol’s ‘insolation’ for absorption Tim.

    The ‘grid dimension’ is too large to differentiate between ‘land surface’ and ‘ocean surface’! Thus, is this ‘latent convection’, or ‘thermal convection’? The ‘presumption’ is cleverly left to the ‘reader’.

    Best regards, Ray.

    • October 4, 2014 at 02:35

      Seems to me there are so many warts with these supposed global measures that the supposed information is not terribly important, will be wonky. Strictly there is no way to get from the little actual data to global, violates sampling.

      Rather like the insolation so called reference network used to refine Trenberth all without a single ocean site.

  1. April 10, 2015 at 13:42

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