4 ms·

If the mean rolling average of all tempreture readings across Australia moved by 0.5 across a twelve month period that would indeed be a significant change that

If the mean rolling average of all tempreture readings across Australia moved by 0.5 across a twelve month period that would indeed be a significant change that would certainly mean something.

spinningarrow 2y ago
Can you elaborate on that? Why would it be significant and what could it mean?
- exe34 2y ago
  it would mean it was warmer.
bluGill 2y ago
That is also something really hard to measure correctly. There are many sources of error that are hard to correct for.
- defrost 2y ago
  The Central Limit Theorem smooths any errors. Decades of observation data make instrument errors very easy to spot. In recent decades daily MODIS (satellite) polar orbit overpasses provide air column and ground temp data that infills station data (from 1900 onwards). There's a science to ground truthing, error detection, and data correction. Here's the gross single number continent wide average over a century: http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi It's not hard to find raw data, finer grids, methodology, etc.
  - bluGill 2y ago
    Only sometimes. It is easier to measure in cities, and thus introduce bias based on whatever pavement is populate. There is a lot of data, and the people who measure this (or at least some of them) are aware of the issues and so correct for them. However you cannot just blindly apply the central limit theorem.
    - defrost 2y ago
      Who said anything about blindly? Apart from yourself, implying that happens as a matter of course?
    - defrost 2y ago
      > It is easier to measure in cities, and thus introduce bias based on whatever pavement is populate. That's a myth. * MODIS sat readings are available under the precessing polar orbit path and are indifferent to urbanisation or not. * National BoM networks have always included stations outside of cities and great care is taken to position stations and to normalise readings. * Urban Heat Island Bias is a myth of long standing; asked and answered three decades ago, two decades ago, a decade ago. Why is it _still_ being raised in 2025? See: https://skepticalscience.com/urban-heat-island-effect-intermediate.htm https://skepticalscience.com/urban-heat-island-effect-interm... https://www.youtube.com/watch?v=pidRKmq2iGI https://www.youtube.com/watch?v=pidRKmq2iGI
ta20240528 2y ago
Indeed, but not if your thermometer could only measure in 2°C increments. You don't gain accuracy by averaging a bunch of rough measurements, especially if the micro-climate has a lot of diversity. Statistics is tough.
- defrost 2y ago
  Luckily the Australian BOM Weather Station specifications require that air and soil temp sensors have a -60° C to +60° C range with a 0.1° C resolution and a ±0.1° C accuracy. The specs are in attachment 2 of the BoM Observation Specification manual. Spurious comments are easy, looking stuff up is tough.

If the mean rolling average of all tempreture readings across Australia moved by 0.5 across a twelve month period that would indeed be a significant change that would certainly mean something.

spinningarrow 2y ago

Can you elaborate on that? Why would it be significant and what could it mean?

exe34 2y ago
it would mean it was warmer.

bluGill 2y ago

That is also something really hard to measure correctly. There are many sources of error that are hard to correct for.

defrost 2y ago
The Central Limit Theorem smooths any errors. Decades of observation data make instrument errors very easy to spot. In recent decades daily MODIS (satellite) polar orbit overpasses provide air column and ground temp data that infills station data (from 1900 onwards). There's a science to ground truthing, error detection, and data correction. Here's the gross single number continent wide average over a century: http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi It's not hard to find raw data, finer grids, methodology, etc.
- bluGill 2y ago
  Only sometimes. It is easier to measure in cities, and thus introduce bias based on whatever pavement is populate. There is a lot of data, and the people who measure this (or at least some of them) are aware of the issues and so correct for them. However you cannot just blindly apply the central limit theorem.
  - defrost 2y ago
    Who said anything about blindly? Apart from yourself, implying that happens as a matter of course?
  - defrost 2y ago
    > It is easier to measure in cities, and thus introduce bias based on whatever pavement is populate. That's a myth. * MODIS sat readings are available under the precessing polar orbit path and are indifferent to urbanisation or not. * National BoM networks have always included stations outside of cities and great care is taken to position stations and to normalise readings. * Urban Heat Island Bias is a myth of long standing; asked and answered three decades ago, two decades ago, a decade ago. Why is it _still_ being raised in 2025? See: https://skepticalscience.com/urban-heat-island-effect-intermediate.htm https://skepticalscience.com/urban-heat-island-effect-interm... https://www.youtube.com/watch?v=pidRKmq2iGI https://www.youtube.com/watch?v=pidRKmq2iGI

ta20240528 2y ago

Indeed, but not if your thermometer could only measure in 2°C increments. You don't gain accuracy by averaging a bunch of rough measurements, especially if the micro-climate has a lot of diversity. Statistics is tough.

defrost 2y ago
Luckily the Australian BOM Weather Station specifications require that air and soil temp sensors have a -60° C to +60° C range with a 0.1° C resolution and a ±0.1° C accuracy. The specs are in attachment 2 of the BoM Observation Specification manual. Spurious comments are easy, looking stuff up is tough.