As part of the ongoing investigation of our evolving climate, we routinely process and analyse meteorological data from successive years, conducting comparative assessments to reveal emerging trends and patterns. In our most recent analysis, we examined the temporal variations in dry bulb temperature, moisture, wind speed, global horizontal irradiation (GHI), direct normal irradiation (DNI), and total precipitation. The analysis covered three 15-year periods—1990-2004, 2005-2019, and the latest 15-year period from 2009 to 2023—as well as a comparison between data from the latest 15 years, the data corresponding to the years and months specified in Industry Standard Meteorological Year (ISMY) files, and the data exclusively from 2023. ISMYs were originally developed for application in house energy rating software used in NatHERS and derive from historical Bureau of Meteorology (BOM) weather data spanning from 1990 to 2015. Over time, they have become the industry’s de facto standard after the CSIRO converted those files to the EPW format (but with gross errors mostly to do with timing). For these scientific purposes, we have prepared ISMYs in EPW format without the CSIRO errors and apply those corrected files to this task.
While the temporal analysis was carried out for all eight capital cities, this issue of Exemplary Advances will focus on the city of Sydney (Observatory Hill). The analysis for other capital cities can be viewed here.
For the analysis of weather elements, we examined the temporal variations in dry bulb temperature, humidity, wind speed, global horizontal irradiation (GHI), direct normal irradiation (DNI), and total precipitation. The analysis involved averaging these elements over three 15-year periods—1990-2004, 2005-2019, and the latest 15-year period from 2009 to 2023—and then comparing the results. A comparison between data from the latest 15 years, the data corresponding to the years and months specified in Industry Standard Meteorological Year (ISMY) files, and the data exclusively from 2023 was also undertaken. ISMYs were originally developed for application in house energy rating software used in NatHERS and derive from historical Bureau of Meteorology (BOM) weather data spanning from 1990 to 2015. Over time, they have become the industry’s de facto standard. It is therefore important to compare against ISMY data, as it provides a reference to gauge alignment with established benchmarks and understand the significance of temporal variations in weather elements.
Comparing 1990-2004 with 2009-2023 showed an increase in the mean temperature of 0.44°C, an increase to moisture of 4.54%, and an increase in wind speed of 9.82%. Global Horizontal Irradiation (GHI) had a decrease of 2.76%, while Direct Normal Irradiation (DNI) had a larger decrease of 9.64%. Meanwhile, comparing 2005-2019 with 2009-2023 showed a very slight decrease in the mean temperature of 0.04°C, an increase to moisture of 1.87%, an increase in wind speed of 1.57%, and a less significant decrease in GHI and DNI of 1.37% and 3.21%, respectively. Total precipitation in 2009-2023 averaged 5.66% more than in 1990-2004. However, compared to the 2005-2019 period, it saw a dramatic 12.12% increase.
Total precipitation in 2009-2023 averaged 5.66% less than in 1990-2004. However, compared to the 2005-2019 period, it saw a dramatic 4.97% increase.
The annual energy consumption trends reveal intriguing patterns across various building archetypes. From 1990 to 2023, all archetypes exhibited increasing trends in cooling and total energy consumption, with consistent rises during the 15-year periods of 1990-2004, 2005-2019, and 2009-2023. In contrast, heating energy consumption generally showed decreasing trends from 1990 to 2023 and 2005 to 2019, though patterns varied among building types. For example, 3-storey and 10-storey office buildings experienced increasing trends from 1990 to 2004 and decreasing trends from 2009 to 2023, while supermarkets showed the opposite, with decreasing trends from 1990 to 2004 and increasing trends from 2009 to 2023. These patterns suggest a warming climate, highlighting the importance of using climate data from the more recent 2009-2023 period in building energy simulations, rather than relying on older ISMY data.
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