Raw vs. Adjusted GHCN Data

Written by Charles of The Dog Ate My Data, Reposted Courtesy of The Dog Ate My Data:
Those of you following the Smoking Gun at Darwin Zero post (from Watts Up With That web site) I made yesterday will have already noted that it is essential in order to scrutinise the data feeding into the IPCC and CRU climate models that we have access to the raw data, the adjustments to that raw data, and the reasons for the adjustments which I will assume have been documented in a professional and reproducible manner as all good scientists would do without question. We hear climate alarmists saying that yes the Climategate scientists at the CRU destroyed emails, and hid from Freedom of information Acts, messed with proxies, and fought to keep other scientists? papers out of the journals ? but that doesn?t affect the data, the data is still good. Well Willis Esenbach?s research shown over on Watts Up With That casts serious doubt on that belief.

Just out of interest I decided to plot the raw temperature data for my home city of Brisbane, Australia from the GISS (ie the raw GHCN data) against the homogenized or adjusted GISS GHCN data. The temperature sensor is located at the Brisbane Eagle Farm Airport which is now our busy main international airport. The data used is the series available from 1950 to 2008. I have aniumated the result to highlight the difference.

As you can see the raw data shows a downward trend of about -0.6 C per century. The unadjusted data however shows an opposite trend of +0.6 C per century. Intuitively as the airport grew from a quiet strip to a busy international jet airport one would think the more recent data would be adjusted downwards for the heat island effect. Instead we see that the data prior to 1978 is adjusted down and the data in recent times was adjusted up. This is why it is essential that the relevant scientists disclose the reasons for each adjustment – the entire warming trend in the Brisbane data is due to the adjustments as the raw data clearly shows a cooling trend. Without being able to check the veracity of the adjustments used the trend cannot be relied upon. Our default position must be that until all data is made available to other scientists to scrutinize and test the data temperature data used to derive the graphs and models used by the IPCC is not to be relied upon for climate modeling or policy making. Now that the cat is out of the bag failure by the data keepers to disclose this data is in direct contravention to UN scientific procedures and indicates that the data has not been dealt with either in a competent or an honest manner.

Below are the individual plots of the Brisbane temperature anomaly used to construct the animation appearing above. All data was downloaded from the GISS website on 9 Dec 2009.