Non - Climatic Data in the GHCN 1870-1910

Non - Climatic Data in the GHCN / USHCN Rural Data 1870-1930

The USA component of the GHCN data is also known as the USHCN ( United States Historical Climate Network). Both data sets are generated by research teams in NOAA / NCDC, so in effect GHCN for the USA equals USHCN. While reviewing city records and city minus rural difference graphs from the USA, many examples of non-climatic anomalies in late 19 century early 20 century rural GHCN records have become obvious. Most of these look to be cold anomalies that would insert artificial warming into century long trends. These USA aberrant temperature data are illustrated here to give a reality check to those who seem convinced that the USA rural temperature data is somehow the best in the world. Like in most countries, rural temperature record data in the USA can contain many non-climatic inhomogeneities that will insert non-climatic warming into large area averaged trends.
These data also call into question the GHCN conclusion in a recent published paper that when you take cities out of global data the warming trend does not change. The reason for this finding could be the existence of pervasive warming errors in global rural data such as illustrated here and the common "uncorrected cooling steps" in city UHI affected data due to moves from urban centres to urban fringe, also illustrated here.
The only way to approach the truth in these issues is to carry out grid cell by grid cell studies so both the trees and the wood can be seen and understood.

Many of these 100 year old cold anomalies in rural USA data would be due to instrument shelter changes, bearing in mind that instrument shelters would likely have been updated earlier at the more professionally maintained city stations.

Note that these instances below of errors in rural data have emerged from looking at city / rural comparisons, no attempt has been made to scour the USHCN / GHCN for these errors. If support was available, that could be done.

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Peoria, Illinois
In this example a huge 2 to 3 degrees C cold anomaly is present in Washington and Galva pre-1890 data compared to Peoria.
There is also an uncorrected cooling move in Peoria circa 1960.

Memphis
In this example all four rural stations around Memphis show non-climatic data to varying extents pre-1930.

Jacksonville Fla
Two of the Jacksonville peripheral rurals, Federal point and Fernandino Beach show pre-1915 and pre-1930 non-climatic cold anomalies in their differences to Jacksonville. The other two station differences, Jacksonville-Madison and Jacksonville-Lake City refect the growing Jacksonville UHI warming faster than the two rurals.

Columbus, Ohio
In this case non-climatic cold data is apparent in Philo and Kenton pre 1900. Also obvious are uncorrected cooling moves in Columbus around mid 1970's and mid 1980's. The usual shambles.

Cincinnati
This example shows a huge cold anomaly in Vevay pre-mid 1880's. Note uncorrected warming change followed by cooling change in Cincinnate circa 1945 to 1950 and signs of cooling moves post 1960 and early 1980's.

Chicago
Two rural stations near Chicago, Galva and Marengo show pre 1890 non-climatic cold data which as in all these cases will add to warming in large area average trends from rural data. Also note gross uncorrected cooling move in Chicago circa 1980.

Atlanta
The more rural Covington near Atlanta shows erratic data mainly cold pre 1903 and Dahlonega also reveals a cold anomaly circa 1900. Uncorrected moves are apparent in Atlanta circa early 1980's.

Toledo, Ohio
Toledo neighbours Hillsdale, Lansing and Wauseon all show pre 1890 cold anomalies while Napoleons shows a circa 1890 anomalously warm cluster.

To wrap up a real GHCN shocker is highlighted below.
Kzyl Zar, old USSR
These are not differences but are various versions for Kzyl Zar and show that the GHCN team selected the most highly warming and ridiculous version of Kzyl Zar as their preferred option to include in their "corrected" database. Probably all the versions have non-climatic errors.
How could the GHCN quality controls pass a warming trend of near 4 degrees C in little more than a decade.
Will this be the worst pro-warming nonsense the GHCN have used ?

You read and saw it all first here.