Mercury Thermometers vs Probes in Automated Weather Stations – Is there a speedup with that?
From Jennifer Marohasy’s Blog.
Jennifer Marohasy
Tuesday, April 18 at 9:30pm US Pacific Time
Wednesday, April 19 at 2:30pm Eastern Standard Time
Listen online:
The Australian Bureau of Meteorology has replaced most mercury thermometers with platinum resistance probes in automated weather stations.
My assessment of nearly twenty years of parallel data from Mildura, and only three years of parallel data from Brisbane airport, indicates that the probes can record both hotter and colder temperatures than mercury. , But Are not equivalent.
Statisticians are known to disagree on the most appropriate statistical test to apply, however, it is advisable to at least provide the name of the test performed and the level of significance, as an attorney will present. details of the case law referenced.
The Bureau claims its full 2019 to 2022 assessment for Brisbane Airport found no statistically significant difference between the probe and the mercury thermometer. But did not provide any details.
More generally, their climate scientist, Blair Trewin, claims the parallel data – temperature series recorded with a mercury thermometer and platinum resistance probe at the same location and at the same time – do not significantly different across their network of about 700 automated devices. weather station although as far as I can tell there is only parallel data for 38 locations.
My analysis of three years of parallel Brisbane Airport data — only recently made available after years of arguing over FOI requirements with the Bureau — found that 41% of the time the probe recorded temperatures hotter than mercury. and 26% of the time cooler. The difference was statistically significant (paired t-test, n = 1094, p < 0.05).
The differences were not randomly distributed and there was a marked discontinuity after December 2019.
I initially thought this step changed from a mean monthly difference of minus 0.28 degrees Celsius in December 2019 to 0.11 degrees Celsius in January 2020 (a difference of almost 0.4 degrees Celsius) represents the recalibration of the probe.
The bureau denied this, explaining that there was a bug in the automatic weather station that was immediately rectified and works to specifications from January 2020 onwards. After January 2020, the probe can record temperatures up to 0.7 degrees Celsius warmer.
I required all Parallel data will be made public, starting with a request for data from the Cape Wilsons lighthouse in 2015.
In 2011, a panel of experts commented that for the past 100 years, the Bureau’s ‘guidelines’ have allowed a tolerance of ±0.5 °C for field testing of glass thermometers. (mercury) or resistance thermometer (probe), and for this reason the Board did Are not ranks the Australian council’s observations among the best in the world.
The time has come for another expert review and all parallel data held by the Bureau to be made public. 15 years of total parallel data is required for Brisbane airport and a similar amount for 37 of the Bureau’s 700 official weather stations.
I will be talking about these issues this afternoon on TNT with the legendary Chris Smith.
Tuesday, April 18 at 9:30pm US Pacific Time
Wednesday, April 19 at 2:30pm Eastern Standard Time
Listen online:
So far, the Bureau has stated many reasons not to make parallel data public. In the case of the Brisbane airport data, they initially stated that manually scanning a handwritten A8 report would be too difficult. When John Abbot’s FOI request ended with the Information Commissioner, the Bureau strangely stated that parallel data for Brisbane airport did not exist.
While providing me with nearly 10,000 scanned A8 reports for Mildura in 2017 following the intervention of then-Environment Minister Josh Frydenberg, the Bureau continued to withhold a number of important pages relating to September 2018. 2012.
I can only estimate the probable difference between the probe and the mercury in September at Mildura until this parallel data is made public. In the meantime, the Bureau upheld its claim that the temperature of 37.7 degrees Celsius recorded by the probe at Mildura on September 22, 2017 was the new hottest record since 1889, despite the temperature recorded by other devices at the time, with a mercury thermometer.
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