A large share of the disruptions in electricity distribution in Finland is caused by wind and windstorms. Snow loads on trees are another or complementary cause for such disruptions. The disruption proneness of power supply to strong winds in Finland, and in similar densely forested countries, seems to reduce in the presence of soil frost.

In a still ongoing study, NordicLink, funded by Nordforsk, we combined the power distribution disruption data (2015-2023, by event) with weather and soil temperature information and estimated the impact of wind and soil frost on disruption occurrence probability. The objective of our work was to find a relation between wind gust speed and the number of power supply interruptions and to determine the effect of soil frost on wind-related faults in the electricity distribution system in Eastern Finland. 

The results indicate that when soil frost is present, trees are less likely to fall onto power lines during high-wind events, reducing the risk of power outages. The frozen soil provides additional support to the trees, making them less likely to uproot under the force of the wind. As expected, we found a positive correlation between the number of power outages and wind speed and a negative correlation between soil frost and wind-related power outages.

The warmer climate will most likely decrease the soil frost, and thus increase the possibility of wind-related power outages in Finland or similar high-latitude countries. However, further research is needed to fully understand the complex relationship between soil frost, wind events, and power outages, and to identify the most effective strategies for mitigating the risk of such outages in the future.

How to cite: Láng-Ritter, I., Mäkelä, A., van Kooten, S., Perrels, A., Gisnås, K., and Laapas, M.: Impacts of soil-frost on wind-related energy grid disturbances, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-395, https://doi.org/10.5194/ems2023-395, 2023.

The climate of Ireland is changing. Extreme rainfall events are responsible for major socio-economic impacts and can be hazardous to life. Short-duration and intense localised rainfall events can cause severe flooding. Estimating the return levels of rainfall thresholds for specific return periods has diverse applications, such as informing the design criteria for drainage schemes, sewerage systems, bridges, gutters, and fluvial flood mitigation measures.

The goal of this research was to calculate return values for various return periods from 2 to 120 years and for specific rainfall durations ranging from 15 minutes to 25 days based on the depth-duration-frequency model described by Fitzgerald (2007), but with a denser network of stations with up-to-date data.

Estimates of rainfall intensities were produced for use in building design in support of Action 203 of Ireland’s Climate Action Plan 2021 - Develop specific climate maps and data for use in building design to enhance resilience in support of climate change adaptation and to support the National Adaptation Framework. This project was carried out by Met Éireann under its strategy ‘Making Ireland Weather and Climate Prepared’ and funded by the Department of Housing, Local Government and Heritage.

The outputs of this research will benefit a wide range of stakeholders currently collaborating with Met Éireann, such as the National Standards Authority of Ireland, the Office of Public Works and Transport Infrastructure Ireland, and the Department of Housing, Local Government and Heritage’s building standards team. This report will also inform policy in delivering key national infrastructure such as housing and building renovation. The results will also be of interest to a diversity of sectors, planners and policy makers to make long, lasting and climate sensitive decisions.

References

Fitzgerald, D. L. 2007. Estimation of point rainfall frequencies. Technical Note no. 61. Dublin: Met Éireann. http://hdl.handle.net/2262/70546

Mateus, C., and Coonan, B. 2023. Estimation of point rainfall frequencies in Ireland. Technical Note No. 68. Dublin: Met Éireann. http://hdl.handle.net/2262/102417 

How to cite: Mateus, C. and Coonan, B.: Rainfall intensities to enhance resilience in support of climate change adaptation in Ireland, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-474, https://doi.org/10.5194/ems2023-474, 2023.

Reducing the Urban Heat Island effect and local implementation of climate adaptation strategies, especially Nature-based Solutions (NbS), are one of the key aspects of tackling climate change impacts in urban areas. Increasing green infrastructure of open spaces and buildings, such as implementing green roofs, unsealing of paved surfaces and planting vegetation, particularly increasing the number of street trees and park areas, is considered to have a cooling effect and can help to reduce extreme heat. In this study we examine the possibility to implement different NbS in a densely built environment and evaluate its cooling performance. The evaluation is done on a micro-scale using the ENVI-met model for a selected area in the City of Vienna and the cooling effect is further analysed in case these measures are implemented on a city-scale by using the MUKLIMO_3 urban climate model. 
The climate adaptation scenarios with different NbS included: 1) reduction of paved surfaces, 2) increase in surface albedo of paved surfaces, 3) implementation of green roofs, 4) new parks including trees and low vegetation and 5) a combination of NbS.  The extent of NbS was quantified for the selected area and proportionally scaled for all densely built areas in the city. Simulations were performed for a representative clear-sky heat day for each NbS scenario as well as for the combination of all NbS. 
The highest cooling effect is found for a combination of all NbS. The results show similar cooling intensity both in microscale and city-scale simulations. For a realistic proportion of NbS implemented in the models, a moderate cooling effect of about 1-2°C can be achieved. In case of city-scale simulations, the maximum difference of about 1.4°C is found in the densely-built areas where the measures were applied. Minor cooling effect can be detected in the surrounding areas as well. 
Additional modelling simulations with variable parameters describing land-use properties were conducted to estimate the uncertainties in the modelling results. Based on the different representation of land use characteristics in the model, variations in the spatial pattern of heat load can be found. The cooling effect also varies spatially, depending on the local implementation of NbS. However, the results show similar cooling efficiency of NbS with minor influence of the background data and the method applied.

How to cite: Zuvela-Aloise, M., Hahn, C., Bügelmayer-Blaschek, M., and Schneider, M.: Modelling the cooling effect of Nature-based Solutions in densely built-up areas for a case study Vienna, Austria, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-316, https://doi.org/10.5194/ems2023-316, 2023.

Met Éireann recently concluded a project to update climate maps and data to support building design standards and perform risk assessments for overheating of buildings. One of the work packages in this project focused on the production of representative weather files for building energy modelling. These are input files containing 365 days of hourly data from a range of weather variables that have the potential to have an impact on the ambient conditions within a building, such as temperature, humidity, solar radiation, wind and pressure. They come in the form of Test Reference Years (TRY), which capture average climatic conditions, and Design Summer Years (DSY), which represent hot summer with overheating events. These were produced at six Irish locations.

Established methodologies were followed for the calculation of past weather files based on hourly observations at synoptic weather stations/airports, with a TRY and 3 DSYs selected at each location. A standardised set of Irish climate projections produced by the TRANSLATE project was used to generate future weather files for a range of future climate scenarios. It is a multi-model ensemble comprising of EURO-CORDEX simulations and higher resolution regional projections produced by the Irish Centre for High-End Computing (ICHEC). TRANSLATE contains 27 different climate scenarios, formed from 3 different time periods, 3 emission scenarios and 3 model sensitivities. The “delta-change” methodology was employed to produce the files at the required hourly resolution, with a TRY and 3 DSYs produced for each future climate scenario.

These data will enable Irish building designers to make more informed decisions regarding the risk of overheating, both for current conditions and the potential changes that will occur due to the warming climate.

How to cite: Griffin, S., Lambkin, K., and Mateus, C.: Climate data for use in building design – Past and Future weather files for overheating risk assessment in Ireland., EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-453, https://doi.org/10.5194/ems2023-453, 2023.

With the aim of supporting the design of healthy, safe, and energy-efficient buildings in the changing climate of Finland, tailored hourly weather data files have been constructed and used to assess indoor conditions, energy efficiency and moisture safety of buildings. First, 30-year hourly weather datasets were compiled using observations at four measurement sites in 1989-2018. These datasets were then transformed to represent alternative future climates by modifying the observational values in accordance with CMIP5 climate model projections. The data files for the recent past and projected future initially contained the following variables: temperature, relative humidity, wind speed and direction, three solar radiation variables and precipitation. Later, the data files were supplemented with atmospheric downward longwave radiation (LW_dn).

For building physics, LW_dn is relevant because it is one of the factors that affect the energy balance of buildings. In the lack of sufficiently long time series of direct measurements, its past values were taken from the ERA5 reanalysis. To produce future time series of LW_dn that are consistent with the future values of the other variables in the weather data sets, machine learning was utilized.

Based on the 30-year multivariable data files for the recent past and future climates, shorter periods of weather information were selected for specific purposes. These included Test Reference Years (TRY) for assessing the average annual energy use for heating and cooling; Moisture Design Years (MDY) for simulations of, e.g., mould growth in building envelope structures; Design Days for Cooling (DDC) at various risks levels; and a Heat Wave Summer (HWS) for space overheating risk, representing a year with severe heatwaves in summer.

The presentation provides examples of climate change impacts on different building types. While average temperature and wind-driven rain are projected to increase, technical aspects in the buildings strongly affect how noticeable impact this has e.g., on mould growth. Future changes in corrosion of reinforced concrete structures and freeze-thaw damage depend on the location of the buildings and the orientation of their facades as well as on durability properties of concrete. More frequent and severe heatwaves in the future increase the risks of overheating, thermal discomfort and adverse health effects, particularly among the elderly, in dwellings without efficient cooling. 

The work is linked to the Healthy Premises 2028 programme, set by the Prime Minister’s Office of Finland, and to the Climate Change and Health (CLIHE) programme of the Academy of Finland.

How to cite: Jylhä, K., Lindfors, A., Ruosteenoja, K., Laukkarinen, A., Lahdensivu, J., Pakkala, T., Kosonen, R., Jokisalo, J., Lanki, T., Kollanus, V., Mäkelä, A., and Vinha, J.: Climatic design conditions for buildings and impacts of climate change in Finland, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-366, https://doi.org/10.5194/ems2023-366, 2023.