Improving the operational forecasts of outdoor Universal Thermal Climate Index with post-processing

Kuzmanović, Danijela (author), Banko, Jana (author), Skok, Gregor (author)

The Universal Thermal Climate Index (UTCI) is a thermal comfort index that describes how the human body experiences ambient conditions. It has units of temperature and considers physiological aspects of the human body. It takes into account the effect of air temperature, humidity, wind, radiation, and clothes. It is increasingly used in many countries as a measure of thermal comfort for outdoor conditions, and its value is calculated as part of the operational meteorological forecast. At the same time, forecasts of outdoor UTCI tend to have a relatively large error caused by the error of meteorological forecasts. In Slovenia, there is a relatively dense network of meteorological stations. Crucially, at these stations, global solar radiation measurements are performed continuously, which makes estimating the actual value of the UTCI more accurate compared to the situation where no radiation measurements are available. We used seven years of measurements in hourly resolution from 42 stations to first verify the operational UTCI forecast for the first forecast day and, secondly, to try to improve the forecast via post-processing. We used two machine-learning methods, linear regression, and neural networks. Both methods have successfully reduced the error in the operational UTCI forecasts. Both methods reduced the daily mean error from about 2.6°C to almost zero, while the daily mean absolute error decreased from 5°C to 3°C for the neural network and 3.5°C for linear regression. Both methods, especially the neural network, also substantially reduced the dependence of the error on the time of the day.

• Language: English
• Keywords: climatology, Universal Thermal Climate Index, thermal comfort, verification, UTCI forecasting, post-processing
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: Str. 965–977
• Numbering: Vol. 68, iss. 5
• PID: 20.500.12556/RUL-156150
• UDC: 551.58
• ISSN on article: 0020-7128
• DOI: 10.1007/s00484-024-02640-6
• COBISS.SI-ID: 187754499
• Publication date in RUL: 10.05.2024

Record is a part of a journal

• Title: International journal of biometeorology
• Shortened title: Int. j. biometeorol.
• Publisher: Springer Nature, International Society of Biometeorology
• ISSN: 0020-7128
• COBISS.SI-ID: 25638400

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: klimatologija, univerzalni toplotni klimatski indeks, termalni indeks, verifikacija

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0188
• Name: Astrofizika in fizika atmosfere