The Urban Climate Observatory (UCO) Berlin, Germany, is an open and long-term infrastructure for integrative research on urban climate, hydro-meteorology, and air quality. Quality-controlled observations are carried out to study interactions between atmospheric processes and urban structures, as well as climate variability and climate change in urban environments. It enables multi-scale, three-dimensional atmospheric studies, integrating observational and numerical modelling methods. The UCO Berlin includes the following components:

The Urban Climate Observation Network (UCON) Berlin provides long-term observations of atmospheric variables (e.g., air temperature, relative humidity, precipitation) in the urban canopy layer at various locations since the 1990s. Since 2015 freely-available data from private weather stations in Berlin and surroundings have systematically been collected via crowdsourcing.

Two radiation- and energy-balance towers in distinctly-different urban settings measure four-component radiation fluxes, turbulent fluxes of sensible and latent heat, and carbon-dioxide fluxes using eddy covariance systems since 2014 and 2018. One tower is an associate site of the European research infrastructure Integrated Carbon Observation System (ICOS) and part of the national ICOS-D network (ID: DE-BeR). The seasonal development of the vegetation in the visible and near-infrared range is observed at both locations using PhenoCams (phenocam.nau.edu).

Ground-based remote sensing is used to study the urban boundary layer and beyond since 2017. Two Doppler-wind lidar systems provide profiles of horizontal and vertical wind speed and direction, as well as information on atmospheric turbulence. Cloud height, cloud cover, and aerosol layers are recorded with ceilometers in an urban and a non-urban setting. A microwave radiometer provides vertical profiles of air temperature and absolute humidity. Finally, an X-band Doppler weather radar with dual polarization for precipitation research is in operation since autumn 2022.

This contribution provides an overview of the UCO Berlin and uses selected findings to highlight benefits of the multi-scale observations for urban atmospheric research.

How to cite: Meier, F., Fenner, D., Holtmann, A., Otto, M., and Scherer, D.: The Urban Climate Observatory (UCO) Berlin for integrative research on atmospheric processes in cities, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-309, https://doi.org/10.5194/icuc12-309, 2025.

In the past century, global climate change and intense land-use modifications – such as the conversion of forests to agriculture or built-up areas – have jointly shaped local climate conditions in many countries across the globe. Reconstructing climate at kilometric scales requires accounting for the local impacts of forest conversions and other land-use changes. 

We tackle this challenge by combining global climate products and historical observation timeseries to create 1x1 km monthly precipitation and temperature fields including the effects of forests and urbanization in Belgium in the 20th and 21st centuries. Station data comprise monthly averages of daily minimum and maximum temperature – 18 series starting in 1880 and 45 starting in 1954 – and monthly cumulative precipitation amounts – 28 starting in 1880 and 143 starting in 1951. Single-point series are interpolated with kriging, and as the stations are located in open, grassy locations, the interpolated fields are assumed to be representative of a rural landscape. The impacts of forests and urban environments on temperature are added at different time steps using historical cadastral data and land cover maps.

This study is part of the project FOURCAST, which investigates how Belgian biodiversity has changed since 1900, linking shifts to local changes in the climatic environment. We believe that such a long-term gridded climatological dataset holds potential for various other research applications, including public health, agriculture, and building heritage. 

How to cite: Tzvetkov, D., De Frenne, P., Ingels, R., Journée, M., Poelmans, L., Teller, J., Hamdi, R., and Caluwaerts, S.: Constructing monthly precipitation and temperature fields over Belgium since 1900 including effects of land use changes , 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-492, https://doi.org/10.5194/icuc12-492, 2025.

The constant growth of population living in urban areas creates new opportunities for urban forest to provides ecosystem services for human wellbeing such as, cooling effect, and carbon neutrality of cities. Nevertheless, experimental observation of carbon and energy exchange in urban forest have been so far fragmented, limited to short period of time, and never spatially distributed. While a considering amount of remote sensing and modelling studies indicates the potential cooling capacity and carbon uptake of urban forest, the impact of climatic extreme events on it is still unclear. Through multiple years of unique Eddy Covariance (EC) observations of a mature urban forest located in southern Europe we highlighted how carbon and water fluxes respond differently, almost as if uncoupled, with evaporative cooling maintained during the climatic drought and net carbon sequestration reversed. A long term EC observation, coupled with  modeling simulations, highlight   the role of urban forest as potential tool for climate and microclimate mitigation with and without drought limitations. Our results have important policy implications for urban forest management and planning and more generally for strategies, on urban forest, in relation to carbon neutrality and thermal comfort. While the urban forest had an annual net loss of CO₂ to the atmosphere, its above- and below- ground biomass and the soil represent a relevant carbon reservoir, and its summer uptake of atmospheric CO₂ enabled evaporative cooling of the microclimate. However, the impact of summer drought reduced the levels of cooling benefits compared to non-drought summers. Our results represents the first long term, and continuous experimental observation to demonstrate that the urban forest cooling capacity in warm seasons can decouple from net CO₂ uptake and will be limited by the amount of water available, either from precipitation or irrigation sources.

How to cite: Zenone, T., Guidolotti, G., Bertolini, T., and Calfapietra, C.: Carbon and water fluxes in urban forest: improving human well - being for a more sustainable society, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-792, https://doi.org/10.5194/icuc12-792, 2025.

The Southwest Integrated Field Laboratory (SW-IFL) is one of four urban integrated field laboratories in the US aimed at advancing the understanding and predictability of complex urban environmental systems. The SW-IFL focuses on urban areas in the state of Arizona, integrating stakeholder engagement, high-resolution urban environmental modeling, and intensive observational campaigns to understand the drivers and potential solutions to extreme heat in hot desert cities. A cornerstone of the project is the summer intensive observational periods during which we deploy numerous platforms and techniques including mobile observatories, vehicle-based traverse instruments, fixed weather stations, eddy covariance flux towers, and weather balloons. The campaign includes citywide measurements as well as observations focused on neighborhood-scale testbed areas. The measurements are used to explore multiple urban science questions including questions focused on the temporal and spatial extent of cooling associated with various land covers and urban cooling strategies such as green and blue infrastructure and cool paving. 

This presentation will provide a detailed overview of the scope of the Intensive Observation Period (IOP) measurements conducted in Phoenix Arizona, US during summer 2024 and discuss findings for some of our testbed sites. As the SW-IFL is in year 3 of a 5-year funding period, we will also discuss opportunities for collaborators to get involved in upcoming summer IOPs.

How to cite: Sailor, D., Andino, J., Barnard, W., Georgescu, M., Gurney, K., Keith, L., Lamer, K., New, J., Schuur, T., Solis, P., and Vivoni, E.: Urban Observation Campaigns as part of the Southwest Integrated Field Laboratory: Assessing the performance of urban cooling strategies in a hot desert city, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-817, https://doi.org/10.5194/icuc12-817, 2025.

Recently, human-centered urban heat assessment and adaptation planning have become increasingly relevant to local governments, leading to the development of numerous plans to address related issues. However, policies that integrate the latest scientific methods and tools are rarely implemented. To guide decision-making, budget planning and policy development, data-driven approaches are gaining more attention. These require local and scientific knowledge to collect relevant data sets, provide interpretation guidelines for city departments, and deliver tailored decision-relevant data at the right time.

The Data2Resilience (D2R) project aims to develop an informative, data-driven dashboard that enables city officials and citizens to learn about thermal comfort, access current heat stress throughout the city and thereby adapt to urban heat conditions. This is achieved with a biometeorological measurement network consisting of 80 stations, which was designed and implemented with the city of Dortmund. The stations are under ownership of the city and part of the smart city ecosystem, which ensures long-term maintenance and data availability. This effort is complemented with a near real-time service that models thermal comfort based on SOLWEIG, using as input in-situ measurements and NWPs from ICON-D2. The output data are provided with a 3 m spatial resolution, to enable street-level decision-making. The results of both approaches are stored in databases and a backend was developed to make this data accessible via an API, which finally serves as the backend of a dashboard to visualize the meteorological conditions of the city for various stakeholders in Dortmund. The dashboard facilitates the exploration and interaction with station data and modeling results to gain a deeper understanding of the local differences of heat stress, while delivering objective numbers to argue and guide heat adaptation measures.

How to cite: Weickhmann, L., Kittner, J., Hüser, C., Sismanidis, P., Reinhart, V., Schmidt, S., and Bechtel, B.: From Station to Stakeholder – A data pipeline to bridge the information gap between measurements and administrative needs, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-850, https://doi.org/10.5194/icuc12-850, 2025.

Urban microclimate monitoring is often limited by the high cost of weather stations, restricting the spatial density needed to capture fine-scale temperature variations. This study presents an alternative low-cost LoRaWAN-based heat sensor, developed for real-time, hyperlocal monitoring. The battery-powered system utilizes an existing LoRaWAN network infrastructure and a community-based LoRaWAN platform, enabling flexible, wireless deployment on existing infrastructure such as lamp posts, without the need for charging cables, Wi-Fi or Ethernet connections. To ensure low setup complexity and minimal maintenance, the sensor employs Over-the-Air Transmission (OATT), allowing automatic network connection and re-connection without manual configuration. With a typical accuracy of ±0.2°C, the system is designed to provide long-term, high-spatial, and high-temporal resolution data for urban climate research.

The paper explores a one-year deployment in East London, involving eight bespoke sensors alongside twenty-four commercial systems with the aim of determining their accuracy, agreement and communication. Results demonstrated a high level of measurement accuracy (Pearson R² = 0.999, mean temperature difference of 0.13°C, within ±0.5°C propagation error well within the combined quoted uncertainties of ±0.4°C). The real-time transmission capability mitigates data loss risks from hardware failures or extreme weather events, a key limitation of traditional data loggers. However, the commercial system’s longer battery life makes it a useful supplementary tool in areas with limited network coverage.

The deployment looks to validates the sensor devices as a cost-effective alternative to conventional weather stations, supporting the development of London’s first low-cost, real-time microclimate monitoring network. By addressing critical data gaps in urban heat island research, the findings highlight the feasibility of affordable, scalable sensor networks for high-resolution urban climate studies, sensor-based model validation, climate adaptation planning, and heat mitigation strategies. The study advances the role of low-cost, city-wide sensor networks in urban climate research, demonstrating their potential for real-time environmental monitoring at scale.

How to cite: Ma, D., Hudson - Smith, A., De Jode, M., Stamp, S., Barrett, E., and Brousse, O.: A Cost-Effective and Scalable LoRa Sensor Network for Real-Time Hyperlocal Microclimate Monitoring, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-863, https://doi.org/10.5194/icuc12-863, 2025.

The topography of Bristol, located in a basin and separated from the Bristol Channel coast by hills and a narrow gorge, creates a unique climate where urban effects occur along with orographic, and coastal effects. Nocturnal cold air pooling in the city centre can compete with urban heat island effects. Bristol is also prone to flooding and air pollution episodes due to frequent inversions in the basin. To support high-resolution atmospheric modelling efforts of the interplay between urban, orographic and coastal effects, in 2024 we deployed an automatic weather station network in the Greater Bristol area. With 40 stations measuring temperature, humidity and precipitation every 5 minutes, the network covers intra-urban differences, different altitudes and varying distances from the coast within a 15 x 15 km area. Stations are installed on lampposts at 3 m height to reflect pedestrian-level urban conditions, with selected stations in parks and rural areas.

We present individual cases and average differences in air temperature and precipitation measured during the first year of operation. Urban heat islands up to 7 K were observed within the Bristol basin. On average, nights in the city centre were 2.6 K warmer in summer and 1.3 K in winter. Frost was four times more common in the rural area than in the city centre. However, for about 10% of the time we observed that higher-elevation suburban areas were warmer compared to the basin where the city centre is located. In 7% of the nights, not the city centre, but stations close to the coast were warmest. Rain gauges provided detailed data on individual storm tracks and events and revealed clear orographic effects. This unique open dataset serves multi-institutional projects to improve and test hectometric urban weather predictions, air pollution dispersion, flooding, and thermal comfort modelling.

How to cite: Christen, A., Barlow, J., Escobar-Ruiz, V., Matthews, J., Plein, M., Chrysoulakis, N., Glazer, R., Grimmond, S., Ludwig, S., Podzis, R., Shallcross, D., van Reeuwijk, M., and Zeeman, M.: A street-level sensor network in support of high-resolution modelling of urban weather and climate in Bristol, UK, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-930, https://doi.org/10.5194/icuc12-930, 2025.

Intensive and frequent surface-based thermal inversions are persistent features of climate in the Arctic region and in cities with cold and long period winter season.  Surface-based inversions formed in cities are most interesting for research, because of their impact on people’s health. Besides, “urban” surface-based inversions differ from “rural” ones, because of interactions with the urban heat island (UHI). Actually, urban surface-based inversions in the Arctic are weakly understood due to poor meteorological monitoring equipment of most Arctic regions and because the reanalysis resolution is too low for the cities.

The main problems arising in the study of urban temperature inversions in the Eastern Arctic are:

• Low technical equipment of the region: radiosonde stations are usually located on the coast and not always near cities, there are no acoustic sounding stations, meteorological stations are most often located outside the city;
• A relatively small area of cities that does not allow conducting research only using reanalysis databases

Given the above problems, the best method for measuring air temperature at different levels is gradient measurements.

 To estimate the frequency of surface-based inversions and spatial distributions in the city of Apatity (Kola Peninsula), Norilsk (Eastern Siberia) and Yakutsk (Far East) measurements during the winter period in 2025 were provided. For this goal, gradient observation complexes based on an automatic temperature recorders TZone Data Logger with sensors at altitudes of 1.5 and 3 meters (Figure 1), respectively, were installed. In Apatity were installed 5 stations for monitoring spatial differences in different urban zones.

Fig.1 Gradient measuring complex in Yakutsk

Preliminary results demonstrated that the recurrence of surface inversions is higher in the central part of Arctic settlements despite higher temperatures than, for example, in Yakutsk.  

This work has been supported by the grant of the Russian Science Foundation, RSF project №23-77-30008

How to cite: Konstantinov, P., Semenova, A., Malutin, I., Baklanov, A., Tananaev, N., Slukovskaya, M., leonov, I., and Maratkanova, V.: Creation of surface layer thermal inversions monitoring network: first examples for Arctic cities , 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-1042, https://doi.org/10.5194/icuc12-1042, 2025.