Urban Meteorology Research

In order to examine and understand the interaction of urban surfaces and the atmosphere, we combine several state-of-the-art methodologies.

Below you can find more information.

Urban observations

The observational part of our research is largely based on measurements carried out at the Kumpula station in Helsinki. We have two active sites where the fluxes of CO2, H2O, heat and aerosol particles are continuously measured using the eddy covariance (EC) technique (Fig. 1). The two sites represent different land uses: the semi-urban Kumpula (blue) has been running since 2004 (Vesala et al. 2008, Järvi et al. 2009) and the urban site, Hotel Torni (red),  since 2009 in the city centre representing a highly built-up land cover (Nordbo et al. 2013, Kurppa et al. 2015). Within the approximate footprint of the Kumpula site, half of the surface is covered with vegetation, whereas in city centre the fraction is only 22%. Kumpula is also ICOS (Integrated Carbon Observation System) associated ecosystem station. In addition to the long-term measurements, we have conducted several EC measurement campaigns related to other compounds including COS, VOC, CO and N2O.

Using the observations, we try to understand how different urban land uses affect the surface exchange processes with particular emphasis on the role of vegetation. We have also extensive ecophysiological observations made in Helsinki area to understand in detail the gas exchange and functioning of urban vegetation. The observations are also used in urban land surface model development.

The current and past projects are

  • CO-CARBON, 2020-2026
  • RI-Urbans, 2021-2025
  • CarboCity, 2019-2024
  • ICOS, 2008 - present
  • The exchange of carbon dioxide, heat and water in urban areas, 2010 - 2013
  • The FP7 project BRIDGE (sustainaBle uRban plannIng Decision support accountinG for urban mEtabolism), 2007 - 2011

Figure: The locations of the two eddy covariance (EC) stations in Helsinki (Karsisto et al. 2015). The 1 km circular areas around the station approximate the source areas for the EC measurements.

Urban land surface model - SUEWS

We actively participate to the development of the Surface Urban Energy and Water Balance Scheme SUEWS (Järvi et al. 2011, 2019, Ward et al. 2016) in collaboration with Prof. Sue Grimmond from the University of Reading. The model simulates the energy and water balance components, and CO2 surface exchange through the use of commonly measured meteorological variables and information on the surface cover. The model is part of the Urban Multi-Scale Environmental Prediction Tool (UMEP, Lindberg et al. 2017). Besides model development, we use SUEWS to examine both long- and short-term behavior of the surface exchanges in different urban areas (Helsinki, Zurich, Paris, Munich, Beijing, Minneapolis, Swindon,...). Current study interests is particularly the potential of urban green areas to sequester carbon from the atmosphere at the same time when regulating heat. The current and past research projects are

  • ICOS-Cities, 2021-2025
  • AIForLESAuto, 2022-2024
  • CO-CARBON, 2020-2026
  • CarboCity, 2019 - 2024
  • Modelling of the surface energy and water balances in high-latitude cities, 2014 - 2017
  • The exchange of carbon dioxide, heat and water in urban areas, 2010 - 2013

Figure: Modelled energy balance at the urban site (Rl) in Montreal during (a) cold snow, (b) warm snow and (c) snow-free periods in 2007-2008 using SUEWS (Järvi et al. 2014).

Large eddy simulation model - PALM

We develop and use the PALM model system to examine flow fields and air quality in various cities (Helsinki, Paris, Beijing, Malmö). We have added the sectional aerosol particle model (SALSA) in PALM so that it can be used to simulate aerosol particle size distribution within complex urban landscapes. Current research topics include the impact of urban planning and increasing amount of electric vehicles on local air quality , structure of coastal urban boundary layer, and impact of thermal turbulence on local air quality. Current and past research projects are

  • CouSCOUS, 2020-2024
  • RI-Urbans, 2021-2025
  • Hienon resoluution ilmanlaatumallinnus kaupunkisuunnittelun tukena, 2017-2018
  • Towards reliable prediction of urban climate using novel methodology development, 2017-2018
  • Modelling air quality and ventilation inside city blocks using large-eddy simulations, 2017-2020
  • Effect of building structures on the ventilation of Helsinki city boulevards, 2016
  • Large eddy simulations of a realistic urban surface, 2014 - 2015

Figure: Flow field in central Helsinki as simulated using PALM model using detailed surface model (M. Auvinen).

Project Funding period Persons Funder
Artificial Intelligence for Urban Low-Emission Autonomous Traffic (AIforLessAuto) 2022-2024 Leena Järvi, Pak Lun Fung, Omar Al-Jaghbeer, Nahid Atashi Research Council of Finland
Research Infrastructures Services Reinforcing Air Quality Monitoring Capacities in European Urban & Industrial AreaS (RI-Urbans) 2021-2025 Leena Järvi, Jani Strömberg EU framework H2020
Pilot Application in Urban Landscapes - towards integrated city observatories for greenhouse gases (PAUL/ICOSCities) 2021-2025 Leena Järvi, Minttu Havu, Jani Strömberg, Jesse Soininen, Anni Karvonen EU framework H2020
Individuals, communities and municipalities mitigating climate change by carbon smart green space (CO-CARBON) 2020-2026 Leena Järvi, Michael Lee, Johanna Hohenthal, Minttu Havu Strategic Research Council
Integrated Carbon Observations System (ICOS) 2008-present Leena Järvi, Jesse Soininen Faculty of Science

Optimal urban planning solutions for maximizing the beneficial impact of urban green space on surface-atmosphere exchanges of energy, water and CO2

2022-2025 Michael Lee Doctoral School in Atmospheric Sciences

Modelling and observing the atmospheric boundary layer in coastal cities

2021-2024 Sasu Karttunen Doctoral School in Atmospheric Sciences
Sustainable urban development emerging from the merger of cutting edge Climate, Social and Computer Sciences (CousCOUS) 2020-2024 Leena Järvi, Xiaoyu Li, Nahid Atashi Research Council of Finland
Urban green space solutions in carbon neutral cities (CarboCity) 2019-2023 Leena Järvi, Jesse Soininen, Yiyang Ding Research Council of Finland
The most optimal green area solutions in present day urban planning to maximise urban carbon stocks 2019-2023 Minttu Havu Tiina and Antti Herlin foundation
Associate professor starting package 2019-2022 Jani Strömberg University of Helsinki
Smart urban solutions for air quality, disasters and city growth 2017-2021 Leena Järvi, Mona Kurppa ERA-PLANET
Modelling air quality and ventilation inside city blocks using large-eddy simulations 2017-2020 Mona Kurppa Doctoral School in Atmospheric Sciences
Fine resolution air quality modelling as support of urban planning 2017-2018 Leena Järvi, Mona Kurppa, Sasu Karttunen Helsinki Metropolitan Region Urban Research Program
Towards reliable prediction of urban climate using novel methodology development 2017-2018 Mikko Auvinen Maj and Tor Nessling foundation
Aerosols, Clouds and Trace Gases Research Infrastructure (ACTRIS-2) 2015-2019 Leena Järvi EU H2020
Modelling of the Surface energy and water balance in high-latitude cities 2014-2016 Tom Kokkonen Maj and Tor Nessling foundation
Carbon dioxide, heat and water exchanges in urban climate 2011-2013 Leena Järvi Academy of Finland
Micrometeorology and air quality in urban areas 2007-2010 Leena Järvi Maj and Tor Nessling Foundation


Our group collaborates with several research groups both nationally and internationally. The main collaborators for the current research topics are

  • Prof. Sue Grimmond, University of Reading, UK
  • Prof. Siegfried Raasch, Leibniz University Hannover, Germany
  • Adj. Prof. Liisa Pirjola, Metropolia, University of Applied Sciences, Finland
  • Prof Laura Ruotsalainen, University of Helsinki, Finland
  • Ass. Prof Sanna Ala-Mantila, University of Helsinki, Finland
  • Prof. Christopher Raymond, University of Helsinki, Finland
  • Prof Thomas Lauvaux, University of Reimns, France
  • Prof. Andreas Christen, University of Freiburg, Germany
  • Dr Topi Rönkkö, Tampere University of Technology, Finland
  • Dr Antti Hellsten, Finnish Meteorological Institute, Finland
  • Prof. Huizi Liu, Chinese Academy of Sciences, China
  • Dr Helen Ward, University of Innsbruck, Austria
  • Ass. Prof. Joe Mcfadden, University of Santa Barbara, California, USA