Although I've been temporarily diverted from my Steele climate science horror story project, I haven't forgotten about it. For instance, responding to Steele's outlandish Jan 7th WattUpWithThat post claiming to "expose USHCN Homogenization insanity" I had promised more information, but there are only so many hours in a day.
Fortunately, today there were a couple posts over at SkepticalScience.com that give an excellent review of this topic. In one Dr. Kevin Cowtan, a bona fide expert in the field explains weather station calibration adjustments, the why and how they're done along with comparing adjusted to unadjusted data.
The second "bulletin inventories rebuttals to two recent articles by Christopher Booker published in the UK's Daily Telegraph claiming that climate scientists have nefariously manipulated temperature data in order to propagate the "myth of manmade climate change".
With thanks to SkepticalScience.com I'll check this off my list and let Dr. Cowtan and John Hartz take it from here:
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Updated 3/27/2015 with this addition from Variable-Variability.blogspot.com
Two new reviews of the homogenization methods used to remove non-climatic changes
Two new reviews of the homogenization methods used to remove non-climatic changes
By coincidence this week two initiatives have been launched to review the methods to remove non-climatic changes from temperature data. One initiative was launched by the Global Warming Policy Foundation (GWPF), a UK free-market think tank. The other by the Task Team on Homogenization (TT-HOM) of the Commission for Climatology (CCl) of the World meteorological organization (WMO). Disclosure: I chair the TT-HOM.
The WMO is one of the oldest international organizations and has meteorological and hydrological services in almost all countries of the world as its members. The international exchange of weather data has always been important for understanding the weather and to make weather predictions. Its main role is to provide guidance and define standards to make collaboration easier. The CCl coordinates climate research, especially when it comes to data measured by the national weather services.
The review on homogenization, which the TT-HOM will write, is thus mainly aimed at helping national weather services produce better quality datasets to study climate change. This will allow the weather services to provide better climate services to help their nations adapt to climate change.
Homogenization
Homogenization is necessary because much has happened in the world between the French and the industrial revolution, two world wars, the rise and the fall of communism, and the start of the internet age. Inevitably many changes have occurred in climate monitoring practices. Many global datasets start in 1880, the year toilet paper was invented in the USA and 3 decades before the T-Ford.
As a consequence, the instruments used to measure temperature have changed, the screens to protect the sensors from the weather have changed and the surrounding of the stations has often been changed and stations have been moved in response. These non-climatic changes in temperature have to be removed as well as possible to make more accurate assessments of how much the world has warmed.
If there is a bias in the trend, statistical homogenization can reduce it. How well trend biases can be removed depends on the density of the network. In industrialised countries a large part of the bias can be removed for the last century. In developing countries and in earlier times removing biases is more difficult and a large part may remain. Because many governments unfortunately limit the exchange of climate data, also the global temperature collections can only remove a part of the trend biases.
Some differences
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Telegraph {and Jim Steele} wrong again on temperature adjustments
Posted on 24 February 2015 by Kevin Cowtan
There has been a vigorous discussion of weather station calibration adjustments in the media over the past few weeks. While these adjustments don't have a big effect on the global temperature record, they are needed to obtain consistent local records from equipment which has changed over time.
Despite this, the Telegraph has produced two highly misleading stories {that are bouncing around the echo-chamber} about the station adjustments, the second including the demonstrably false claim that they are responsible for the recent rapid warming of the Arctic.
