The University of Helsinki is the oldest and largest institution of academic education in Finland, an international scientific community of 40,000 students and researchers. In international university rankings, UH typically ranks among the top 100. The University seeks solutions for global challenges and creates new ways of thinking for the best of humanity. The university is divided into 11 faculties, including Faculty of Science, Faculty of Biological and Environmental Sciences, and Faculty of Agriculture and Forestry. Furthermore, the University accommodates several independent research-oriented institutes, multidisciplinary research networks and campus units (e.g. Environmental Change Research Unit), as well as units attending to duties of national authority.

In the project UH is represented by the Institute for Atmospheric and Earth System Research (INAR) – a joint unit under the Faculty of Science and Faculty of Agriculture and Forestry with ca. 220 research staff based in Helsinki. INAR aims to strengthen the internationally leading, integrated multidisciplinary research and education environment for atmospheric and Earth system science and to feed in scientific results to national and international environment and climate policy. It performs multiscale research from molecular to global scale and focuses on climate change, air quality, biogeochemical cycles and ecosystem processes. The work is based on a network of field stations producing extensive long-term data on atmospheric properties and ecological mass fluxes in different types of environments and regions, including Arctic, boreal and tropical ecosystems, and on focused experiments and modeling aimed at understanding the observed patterns. Every year the division organizes several international intensive courses, tailored to meet student’s special needs, extensively using its field stations and e-learning facilities. INAR coordinates the national Centre of Excellence in Atmospheric Science – From Molecular and Biological processes to the Global Climate (https://www.atm.helsinki.fi/FCoE/) and hosts the Headquarters of Pan-Eurasian Experiment (PEEX) – multidisciplinary climate change, air quality, environment and research infrastructure program (https://www.atm.helsinki.fi/peex/).

The Institute for Atmospheric and Earth System Research (INAR) unit at the University of Helsinki (UH) that started in operation on 1^st of January 2018. INAR is a multi- and interdisciplinary research unit based in physics, chemistry, meteorology, forest sciences, environmental sciences and social sciences. INAR has national partners in the Finnish Meteorological Institute, University of Eastern Finland, and Tampere University of Technology. The INAR unit of UH consists of 4 organizational parts: INAR / Physics, Faculty of Science; INAR / Forest Sciences, Faculty of Agriculture and Forestry; INAR / Chemistry, Faculty of Science; and INAR / Geosciences, Faculty of Science. INAR (the former Division of Atmospheric Sciences) has over 30 years of experience in atmospheric research. More than 150 scientists and doctoral students are currently engaged in this area. The main research subjects are aerosol dynamics, atmospheric chemistry, climate change, dynamical and radar meteorology, forest-atmosphere and aerosol-cloud-climate interactions, and urban air quality. With the multidisciplinary team structure and comprehensive measurement and modelling research tools, INAR is one of a few groups in the world capable of efficiently combining the climate change, greenhouse and trace gases, aerosol and vegetation processes. The INARs major items of technical equipment are: (i) field stations network, (ii) laboratories, (iii) modelling tools and high performance computing capacity, including remote sensing data and airborne measurements. INAR operates 4 field stations in Finland called the SMEAR (Station for Measuring Forest Ecosystem Atmosphere Relations) stations. The SMEAR II is the world leading station due to its comprehensive research program and due to its unique time series of observations for aerosol formation and biogeochemical fluxes. For the global coverage, we analyze data from several field sites in “climate space” to identify and prioritize key gaps in understanding of global features in the climate change. Via Pan-Eurasian EXperiment (PEEX) program the UH provides a unique sets of data to be utilized for the atmosphere-ecosystem research in the circumpolar Arctic-boreal context. INAR has 3 laboratories: (i) Aerosol Particle Laboratory (mass spectrometers, particle generators, aerosol, cluster and ion spectrometers, and equipment for analyzing the hygroscopic properties and volatility of aerosol particles, characterization of novel instrumentation, calibration, optimization), (ii) Ecophysiological laboratory (growth chambers, mini-rhizotrons, physiological measurement systems with stable isotope equipment), and (iii) Laboratory of Analytical Chemistry (suite of commercial and self-modified/self-constructed instruments, incl. aerosol mass spectrometry, portable gas chromatography-mass spectrometry, multidimensional chromatographic techniques, size-selective sampling, combination of mass spectrometry and chromatography).

INAR’s available models as research tools establish a hierarchy reaching across the scales of UH research interests, and in particular, the EC-Earth, MPI-ESM, Enviro-HIRLAM, SOSAA, MALTE-BOX, ADCHAM, ADCHEM, models. Such model framework gives an opportunity to develop and combine models operating at different spatial and temporal scales, and considering different processes from micro-scale processes in box models to a large scale circulation. Such INAR capacity is supported by the IT Center for Science Ltd (CSC) as a workflow and computing and data storage infrastructure. The CSC has an active role in the INAR’s multi-scale modelling from global/ climate scales to high resolution/ large eddy simulations. In terms of validity of initial conditions for multi-decadal predictions INAR has expertise on the use of ocean reanalysis for both initialisation of multi-decadal predictions and analysis of multi-decadal variability. INAR also carries out polar research expeditions and provides data for the detailed analysis on the mechanisms of secondary new particle formation and related chemistry via direct measurements of aerosol precursor vapours, cluster chemical composition, physical properties of aerosol, etc.  INAR has active role in the international Arctic collaboration like SAON (Sustaining Arctic Observing Network), U-Artic thematic network, coordinates the EU Horizon-2020 iCUPE (Integrative and Comprehensive Understanding on Polar Environments) and contributes INTAROS (Integrated Arctic Observation Systm) projects. Via the PEEX program the INAR provides access to research infrastructure and networking to collaborating European, Russian and Chinese partners. Furthermore, INAR has a long term experience in organizing data analysis courses and trainings for PostDocs and students having different educational backgrounds and representing different disciplines. INAR also coordinates the Climate University project in Finland, which is providing e-platform for Virtual Climate University and an online Learning and Sustainability Transition in a post-COVID-19 World.

https://www2.helsinki.fi/en/inar-institute-for-atmospheric-and-earth-system-research