Rural Stations adjusting Dublin Airport: Anomaly Consistency

This is most certainly not a definitive study of the consistency of the rural station anomalies used to adjust urban stations in Gistemp. It is simply a gallery of plots of the rural station anomalies used to adjust one particular urban station, my “home” station, Dublin Airport, plotted out of curiosity to see whether the closer stations were perhaps more consistent, or those offshore less consistent. Sharing these plots here is also an opportunity to see how the gallery feature of this WordPress theme works.

21 rural stations are used to adjust Dublin Airport. 8 of these are located in Ireland, the remainder on the neighbouring island, 7 in England, 5 in Scotland and 1 in Wales. In these plots different colours are used to distinguish stations in different distance ranges or different countries. As Dublin Airport has a long temperature record, making the different rural station records difficult to distinguish when the full record is plotted, additional plots for shorter time spans have also been plotted.

In order of increasing distance these 21 stations, with their time span, number of years, weight and distance, are:

1950-1990  41 [wgt: 0.839   80.3 km] 621039710000 MULLINGAR
1950-1990  41 [wgt: 0.779  110.6 km] 621039740000 CLONES
1931-2009  79 [wgt: 0.773  113.5 km] 651033020001 VALLEY
1955-1990  36 [wgt: 0.764  118.0 km] 621039650000 BIRR
1950-1990  41 [wgt: 0.624  188.1 km] 621039700000 CLAREMORRIS
1956-1990  35 [wgt: 0.553  223.5 km] 621039520000 ROCHES POINT
1956-2009  54 [wgt: 0.533  233.6 km] 621039800004 MALIN HEAD
1961-2009  49 [wgt: 0.470  265.1 km] 621039760004 BELMULLET
1880-1969  90 [wgt: 0.447  276.3 km] 651032090010 DUMFRIES
1931-2009  79 [wgt: 0.426  287.2 km] 651031620003 ESKDALEMUIR
1880-1975  96 [wgt: 0.411  294.7 km] 651035210010 ROSS-ON-WYE
1880-2009 130 [wgt: 0.365  317.4 km] 621039530005 VALENTIA OBSE
1971-2009  39 [wgt: 0.352  324.3 km] 651032570001 LEEMING
1880-1969  90 [wgt: 0.318  340.8 km] 651033550010 YORK
1931-2009  79 [wgt: 0.304  347.8 km] 651031000001 TIREE
1880-1900  21 [wgt: 0.294  353.1 km] 651038170010 TRURO
1884-1903  20 [wgt: 0.231  384.7 km] 651030380010 BEN NEVIS
1880-1980 101 [wgt: 0.225  387.4 km] 651036570010 OXFORD
1880-1969  87 [wgt: 0.218  391.3 km] 651032920010 SCARBOROUGH
1880-1969  90 [wgt: 0.124  438.2 km] 651030720010 BRAEMAR
1880-1900  21 [wgt: 0.115  442.4 km] 651038740010 OSBORNE

or in the order in which they are combined, starting with the longest record (where after Valentia Observatory the next Irish Station is Malin Head):

1880-2009 130 [wgt: 0.365  317.4 km] 621039530005 VALENTIA OBSE
1880-1980 101 [wgt: 0.225  387.4 km] 651036570010 OXFORD
1880-1975  96 [wgt: 0.411  294.7 km] 651035210010 ROSS-ON-WYE
1880-1969  90 [wgt: 0.318  340.8 km] 651033550010 YORK
1880-1969  90 [wgt: 0.447  276.3 km] 651032090010 DUMFRIES
1880-1969  90 [wgt: 0.124  438.2 km] 651030720010 BRAEMAR
1880-1969  87 [wgt: 0.218  391.3 km] 651032920010 SCARBOROUGH
1931-2009  79 [wgt: 0.773  113.5 km] 651033020001 VALLEY
1931-2009  79 [wgt: 0.426  287.2 km] 651031620003 ESKDALEMUIR
1931-2009  79 [wgt: 0.304  347.8 km] 651031000001 TIREE
1956-2009  54 [wgt: 0.533  233.6 km] 621039800004 MALIN HEAD
1961-2009  49 [wgt: 0.470  265.1 km] 621039760004 BELMULLET
1950-1990  41 [wgt: 0.779  110.6 km] 621039740000 CLONES
1950-1990  41 [wgt: 0.839   80.3 km] 621039710000 MULLINGAR
1950-1990  41 [wgt: 0.624  188.1 km] 621039700000 CLAREMORRIS
1971-2009  39 [wgt: 0.352  324.3 km] 651032570001 LEEMING
1955-1990  36 [wgt: 0.764  118.0 km] 621039650000 BIRR
1956-1990  35 [wgt: 0.553  223.5 km] 621039520000 ROCHES POINT
1880-1900  21 [wgt: 0.115  442.4 km] 651038740010 OSBORNE
1880-1900  21 [wgt: 0.294  353.1 km] 651038170010 TRURO
1884-1903  20 [wgt: 0.231  384.7 km] 651030380010 BEN NEVIS

The inclusion of Ben Nevis in GHCN (along with Fort William, also with a record only from 1884 to 1903, but now reclassified as urban on the basis of night time radiance and no longer an adjuster for Dublin Airport) strikes me as rather odd when there are few other current stations in Scotland included. The historical significance of this pair of stations is hardly a relevant justification (the Ben Nevis observatory, abandoned in 1903, is approximately 7 km horizontally distant from and 1323 m vertically above Fort William, definitely rural in 1903 whatever the satellite may say, neatly demonstrating the lapse rate with altitude).

In the following plots the heavy green line is the combined rural record, the thin lines, classified by distance or country using different colours, are the 21 individual rural stations contributing to this combined rural record.

Rural stations classified by distance: 1880-2009

Rural stations classified by distance: 1880-2009

Rural stations classified by distance: 1980-2009

Rural stations classified by distance: 1980-2009

Rural stations classified by distance: 1960-1990

Rural stations classified by distance: 1960-1990

Rural stations classified by country: 1880-2009

Rural stations classified by country: 1880-2009

Rural stations classified by country: 1960-2009

Rural stations classified by country: 1960-2009

Rural stations classified by country: 1980-2009

Rural stations classified by country: 1980-2009

Rural stations classified by country: 1960-1990

Rural stations classified by country: 1960-1990

Rural stations classified by country: 1920-1960

Rural stations classified by country: 1920-1960

Rural stations classified by country: 1880-1920

Rural stations classified by country: 1880-1920

Rural stations classified by country: 1960-1970

Rural stations classified by country: 1960-1970

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2 Responses to Rural Stations adjusting Dublin Airport: Anomaly Consistency

  1. I think it would be helpful if you added a bit of interpretation to your charts. Do you think Gistemp did a reasonable job adjusting Dublin airport, or no? And why?

    TIA & cheers, Pete Tillman — who spent a year at Belvedere College long, long ago

    • oneillp says:

      As I said, this was most certainly not a definitive study. I’ve put considerable effort into implementing Gistemp and understanding how it operates, and so far relatively little effort into interpreting the output, so I have tried to avoid falling into the trap of prematurely interpreting something which I have not yet fully worked through. This post was a by-product of adding code to my Gistemp implementation to generate the R script needed to plot the rural adjuster records whenever information concerning an urban station is generated. This was my first test case, and as Dublin Airport is a long record with a reasonable number of rural adjusters I thought these charts I was generating to aid my own understanding might be useful to others similarly seeking to understand the workings of Gistemp, even though I am not yet ready to add much interpretation.

      As for the adjustment of Dublin Airport, it was this adjustment which triggered my curiosity initially, so it would be fair to say that it caught my attention as something which I would regard as suspect. But this is just one station.

      I am halfway through preparation of a lengthy post on the draft Hansen et al. [2010], which should be ready later this week, based on my understanding so far of Gistemp. My opinion is that the GISS analysis in that paper may or may not be correct – I would not at this stage venture an opinion – but that the uncertainty involved is underestimated.

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