The Australian Bureau of Meteorology (BOM) revises the raw temperature data it collects from its weather stations. The process—which the BOM calls 'homogenisation'—adjusts the temperature readings at a given location to take into account nearby measurements. The homogenised temperatures form the ACORN-SAT dataset on which all official reporting on climate change is based.
Due to the lack of transparency surrounding the raw data and the adjustments that are made to them, homogenisation has proved to be highly controversial.
Tom Quirk, an AEF Director, has sought to throw light on the issue by comparing satellite temperature measurements of the lower troposphere over Australia with the near-surface temperatures published by the Australian Bureau of Meteorology (BOM) for the period from 1979 to 2017. The satellite data were sourced from the University of Alabama in Huntsville (UAH) in the US. To account for differences due to altitude in these two datasets, Tom used standardised differences in the temperature anomaly—the difference between the temperature recorded at a particular time and the long-term average for the place in question.
Tom found a significant loss of correlation between the UAH and BOM temperature series in the late 1990s. This was when automatic weather stations with electronic temperature measurement replaced manned stations, which used mercury and spirit thermometers. The sources of the temperature differences are the instrument changes and particularly the step-changes in temperature adjustments introduced as part of the homogenisation process.
Tom Quirk, an AEF Director, has published an interesting paper on Jo Nova's website [link here] looking at the relationship between rainfall and atmospheric temperature in Australia. In it Tom seeks to answer the question as to whether temperature determines rainfall or vice versa. This is an important issue in climate modelling and long-term temperature projections made with climate models.
Tom has found a clear interaction between temperature and rainfall. This was based on his analysis of standardised temperature and rainfall anomalies—the difference between the value in any given period and the long term average for the variable in question. For this purpose he used the near-surface temperature and rainfall datasets published by the Australian Bureau of Meteorology (BOM) and the lower troposphere temperature dataset of the University of Alabama in Huntsville (UAH) in the US.
The sensitivity of the UAH-BOM temperature anomaly and the rainfall anomaly varied with both the rainfall and the period of time the moisture remained on the ground. This reflects the fact that evaporation cools near- surface temperatures but not those in the lower troposphere. With above-average rainfall, the BOM temperature anomaly may be less than the UAH temperature anomaly, while with below-average rainfall the reverse occurs and the BOM temperature anomaly exceeds the UAH temperature anomaly.
A copy of Tom's paper may be downloaded from here.
A review and commentary on topical matters concerning the science, economics, and governance associated with climate change developments.
By Alan Moran
1 March 2018
Evidence on climate trends and their effects
Work conducted by highly respected NASA scientist Roy Spencer estimates a maximum increase of 1.54°C in global temperatures from greenhouse gases, less than half that estimated by the IPCC modellers.
Compounding this, a peer reviewed piece on climate change finds the datasets used to develop climate models are not a valid representation of reality and, due to data adjustments that removed their cyclical temperature patterns, are totally inconsistent with published and credible U.S. and other temperature records.
Very detailed examinations of over 20 areas across the world has shown no increase in temperatures over the past 70 years and more. News followed about how penguins were going to be drastically reduced in numbers as a result of Antarctic warming. But according to the there is no such warming taking place.
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