Cherries, anyone? Another data “trick” in Australia

Ken Stewart, February 2010

Update: 25-02-10

I have improved the graphs after readers’ suggestions and assistance from Jo Nova.  I have revised the GISS warming from 1.7 to “over 1.6” degrees /100 years.

As a follow up to my analysis of temperature data for Mackay and Te Kowai, this study compares Goddard Institute of Space Studies (GISS) data with data from the Bureau of Meteorology for Gladstone and “nearby” sites in regional Queensland, and finds further inexplicable treatment of data leading to an exaggerated warming trend.

Gladstone is an old port, meatworks, and fishing town, now an industrial city with a power station, bauxite refinery and aluminium smelter, plus a coal terminal.  Interestingly, GISS makes NO homogenisation adjustment for Gladstone, and that aroused my curiosity.

 

The Australian Bureau of Meteorology (BOM) has 3 records for Gladstone.  The Post Office from 1909 to 1956 which is dead flat at about 22 degrees; Gladstone Radar from 1958 to 2009, which is immediately 1 degree warmer, and the Airport from 1994  to 2009, half to 1 degree cooler than Radar.  Please note: all my analysis is from 1908-2009, 102 years.  BOM data starts at 1909.

GISS get their data directly from GHCN (Global Historical Climatology Network). Which do you think GISS/GHCN uses? 

The warm one of course.  But how they use it is cynical- and informative.

When developing station data, GISS state that Step 1 is “combining sources at the same location”.  While GISS correctly claim they make no adjustment to their Gladstone data, GHCN/GISS have  “accidentally” ignored 41 years of the earlier BOM data, which shows a flat trend at about 22 degrees.  They have also completely ignored data from the Airport which is about 0.8 degree below Radar.   

But- and this is critical- they splice the last 6 years from the PO onto Gladstone Radar.  Have a closer look at this.

The Radar data is about 1 degree warmer than the PO. Making a trend from this spliced data is very questionable.   As well, the data for Radar shows an upwards movement of about 0.5 degree in the last decade. 

Possibly GISS would say they’re only interested in 1951-1980 figures.  However this has the effect of dropping the starting point.

The result is a warming trend of over1.6 degrees per 100 years where none can reasonably be calculated.  The best they could reasonably have hoped for, by leaving out those 6 years might be about 1.5 degrees per 100 years, which is close but leaves out a lot of data, or by splicing the PO with the Airport, about 0.9 degrees.  Here are plots of these two options:

Option 1- Radar trend, with PO 1951-1956 deleted (1.5 C):

 

Option 2- Post Office spliced with Airport (0.9C):

I would propose a far better solution: they could have adjusted Radar down by 0.8 degrees (the average difference from Airport) to produce this:

Option 3- Radar adjusted -0.8C for Airport, then spliced to PO (0.7C):

Now isn’t that a more elegant solution?  That produces a trend of ~ 0.7 degrees per Century.

So perhaps GHCN chose this 1.6 degrees per century slope to match that of nearby rural stations?  Well actually, no, nothing matches. Then perhaps GISS homogenises Gladstone’s data to match the mean of neighbouring stations.  No again- GISS have not made any adjustments for “inhomogeneities” such as station movement from PO to Radar.   I have included the graphs and notes in an Appendix below for you to check- I find them interesting.  For the sake of brevity, I will skip straight to the conclusion.

Conclusion:

Although GISS can truthfully say they have not adjusted the GHCN data, the splicing of the last 6 years of the Post Office dataset to the warmer Gladstone Radar leads to a trend of more than 1.6 degrees Celsius per Century. 

I have shown three possible options for more appropriate adjustments to combine all temperatures at the one site. Of these, the highest trend is about 1.5 degrees, which is close to the trend (1.4 degrees) of the nearest rural sites.  Examination of these sites shows that their data is of questionable quality.  The second option produces a trend of 0.9 degrees, and the third and (in my opinion) best option, 0.7 degrees. The average trend of the 5 nearest long-record rural sites (0.8 degrees) is between these last two options and so matches well.  Nearby cities of Rockhampton and Bundaberg show adjusted trends of about 0.7 and 0.5 degrees respectively, and Maryborough, ignored by GHCN, shows a trend of 0.4 degrees. 

Thus the GISS record for Gladstone is derived from cynically cherry-picked data.  The resulting trend of more than 1.6 degrees Celsius per Century cannot be justified.  The record is false.  

At the GISS website, the responsible NASA official is listed as Dr James Hansen.  I will leave it to others to decide what he is responsible for.

References

http://data.giss.nasa.gov/gistemp/station_data/

http://www.bom.gov.au/climate/data/weather-data.shtml

http://www.bom.gov.au/other/disclaimer.shtml

http://www.bom.gov.au/other/copyright.shtml#acknowledgements

http://www.appinsys.com/GlobalWarming/climap.aspx?area=australia

Appendix

Mt Morgan has a cooling trend but has many gaps.

Biloela DPI, like many stations,  has a gap of 8 years from 1956-1965.  When the data resumes, it has jumped by 0.5 degree and  continues rising at this 2 degrees/ 100 years rate.  Why would a rural site, only 83 km from Mt Morgan, be warming at this rate?  Interesting.

Yeppoon’s data is too short and patchy to be much use.

Monto has a patchy record with gaps, only from 1962.  It also shows a trend of 2 degrees per 100 years.  The airport’s very scanty data appears to be half to 1 degree below the township.  What happened to the data before 1962?  Monto was settled in the 1920s.  GISS calls it “Monto Post Office was 03”.  What was the “03” ?  Without the missing data no conclusions can be reached.

Lady Elliott Island shows a trend of about 1.6 degrees warming, but note the cooling, warming, cooling- very interesting.  I will check coastal and island data in a later study.

Baralaba’s record is far too short and patchy.

Although the average of  these 4 stations (excluding Yeppoon and Baralaba) of 1.4 degrees is still less than the warming at Gladstone shown by GISS/GHCN, the data quality may not be good enough to  use any of these except Lady Elliott Island to “justify” Gladstone’s data.  Let’s look at some longer records.

Childers has a trend of about 0.9 degree per 100years (according to GISS),  but only about 0.2 degree up to 1956 when there’s an 8 year gap.

Gayndah, one of the oldest towns in Queensland, shows a linear trend of about 1.4 degrees /100 years.  Note the 4^th order polynomial clearly shows the flat trend to the 1950s, and the 1.1 degree rise since then.  Incidentally, Gayndah’s record goes back to 1893, with the hottest year on record being 1897, but I will stick with my 102 year analysis as that matches the majority of long records and BOM is not confident about much data before 1910.

Sandy Cape Lighthouse shows a linear trend of about 0.5 degree/ century, and a small cycle is very evident.  Note the 1940s.

Gympie is 291km south, and a large regional town, once a roaring gold rush town.  GISS shows a trend of about 0.5 degrees/Century, and BOM 0.3 degrees.  30 years cooling!

Emerald, 316km inland, shows maybe 0.8 degrees over 100 years.  Note the large step up (UHI effect?), after a declining trend, from the 1970s onwards, when the town boomed with expansion of irrigation, then coal mining.  Also note the warm period in the early 20th Century.  Airport data seems flat or lower.  Handle cautiously.

The average of these long term stations’ trends is 0.8 degrees- midway between my adjustment Options 2 and 3.

Next, let’s compare Gladstone with its next door cities, Rockhampton, 95 km north, and Bundaberg, 159 km south, both adjusted appropriately.  I will be studying their adjustments in detail in the near future.

 Rocky– adjusted trend about 0.7 degree.

Bundy– adjusted trend about 0.5 degrees.

Even more interesting is a station that GHCN and GISS totally ignore- Maryborough, a small city with a long record, about 240 km south. 

The trend?  Maybe 0.4 degrees.