The Multi-Scale Modelling (MSM) Group is subdivided into two sub-groups: the Atmospheric Modelling Group (AMG), led by Dr.

Michael Boy, and the Earth System Modelling (ESM) Group, led by Dr. Risto Makkonen

Michael Boy

Group Leader - Atmosphereic Modelling Group

Michael Boy has finished his two-year fellowship position at NCAR in 2007 and afterwards he started with one PhD student as a supervisor in the Division of Atmospheric Science at the University of Helsinki. In the end of 2009 he established the Atmosphere Modelling Group and in the first two years he mostly used his time in training young promising bachelor and master students on different atmospheric models. This time-intensive supervision of several under-graduated students succeeded in a very effective, ambiguous and well-trained group of talented young PhD students.

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For information concerning the AMG subgroup please contact Michael Boy (michael.boy(at)

Risto Makkonen

Group Leader - Earth System Modelling Group

Risto Makkonen's interests include aerosol nucleation, aerosol-cloud-climate interactions and climate feedbacks. His main tools include global aerosol-climate models and Earth System Models. Previously, He has worked on climate effects of anthropogenic and natural aerosols, effect of nitric acid on cloud droplet formation, secondary organic aerosol formation and role of new particle formation on climate. He works with integration of observations to simulation data, in order to evaluate and constrain the aerosol models.

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For information concerning the ESM subgroup please contact Risto Makkonen (risto.makkonen(at)

Metin Baykara

Atmospheric Modelling Group

Metin Baykara received his PhD in 2018, from Istanbul Technical University, Turkey, with the title: "Understanding the Sources and the Extent of Atmospheric Particulate Matter Problem over Turkey Using Mesoscale Chemical Transport Model". He has extensive experience in anthropogenic emissions processing and modeling, and regional level meteorology - chemical transport modelling. He has joined the group in March 2019 and is mainly working on SOSAA model development and its application to investigate the air pollutions phenomena at Istanbul, Turkey.

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Jian-Pu Bian

Earth System Modelling Group

Jian-Pu Bian is a PhD-student who works on paleoclimate dynamics and EC-Earth simulations during the Mid-Holocene (MH) period in cooperation with Stockholm University and Lund University. His background is tropical dynamics and extratropics-tropics interaction.

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Dean Chen

Atmospheric Modelling Group

Dean Chen started his PhD in the modelling group in November 2016 with the topic "Aerosols-formation, growth, transformation and a study on its anthropogenic versus biogenic precursor". He will apply different models to study the formation of secondary organic aerosols (SOA) at the SMEAR II in Hyytiälä and the SORPES station in Nanjing, China.

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Petri Clusius

Atmospheric Modelling Group

Petri Clusius started his physics studies in 2016 and did his bachelor thesis about modelling atmospheric new particle formation in Hyytiälä due to ammonia and sulfuric acid. The focus in his master thesis was on the development of the new Atmospherically Relevant Chemistry and Aerosol Box Model – ARCA box. In his PhD studies he is focusing now on the contributing role of biogenic hydrocarbons emitted from forests to future climate warming.

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Chenjuan Deng

Atmospheric Modelling Groug

Chenjuan Deng’ s main research topic is investigating the atmospheric nucleation and growth in the polluted environments combining the measuring and modeling results. She joined the MSM group in November, 2021 as a visiting PhD student from Tsinghua University, China. She is currently working on obtaining the true new particle growth rates from the measured and modeled aerosol size distributions in the real atmosphere. By combing the measuring and the modeling results, she hopes she can gain a deeper insight into atmospheric new particle formation and growth in the polluted environments.

Dian Ding

Atmospheric Modelling Group

Dian Ding joined the group in 2021 as a postdoc. Her main research interest is to use the aerosol box model and regional dispersion model coupled with aerosol sectional module to study the dynamics of the particle size distribution in urban environments.

Benjamin Foreback

Atmospheric Modelling Group

Benjamin Foreback received his Master of Science in January 2019 with the title: "Development of the MEGAN3 BVOC Emission Model for use with the SILAM Chemical Transport Model".

He is now developing the SOSAA model with application to air quality in Beijing, focusing on severe pollution episodes. He is also a member of the Air Quality Group.

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Alexander Mahura

Earth System Modelling Group

Alexander Mahura's fields of research are modelling of atmospheric processes and transport of pollutants (including radionuclides) on local-meso-regional-hemispheric scales, on-line integrated meteorology-chemistry-aerosols modelling at regional-urban scales, impact of urban areas on meteorology and atmospheric composition, atmospheric chemistry, atmospheric boundary layer processes, environmental impact and risk assessment, fine-scale road weather forecasting, birch pollen modelling, numerical weather prediction, and statistics.

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Lukas Pichelstorfer

Atmospheric Modelling Group

Lukas Pichelstorfer is an computational and experimental aerosol physicist. At University of Vienna (Austria) he did an experimental Master Thesis in the field of heterogeneous nucleation. After that he moved to Salzburg (Austria) to do his PhD by modelling aerosol dynamics in the human lung. In the course of a Schrödinger Grant, he is currently at University of Helsinki working on the “Temperature dependent formation of HOM from BVOCs and AVOCs and its atmospheric relevance” within the Atmospheric Processes sub-group lead by Michael Boy.

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Pontus Roldin

Atmospheric Modelling Group

Pontus Roldin received his PhD in Physics, Lund University, Sweden with the title of thesis: "Process based Modelling of Chemical and Physical Aerosol Properties Relevant for Climate and Health" in 2013. He joined the group in March 2014 for two years and is mainly working on the aerosol dynamic modelling in different models. Since 2016 he is back at the University of Lund with a strong cooperation with the modelling group and frequent visits in Helsinki.

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Victoria Sinclair

Earth System Modelling Group

My current research covers a range of topics within dynamical and synoptic meteorology. Current specific topics of interest include the governing dynamics of synoptic-scale fronts, the interaction of mesoscale and synoptic-scale systems with the atmospheric boundary layer, low level jets, and the transport of moisture by weather systems to the polar regions. I use two numerical weather prediction models to address these questions; the Weather Research and Forecasting (WRF) model and Open Integrated Forecast System (OpenIFS).

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Juniper Tyree

Juniper Tyree began their computer science studies in 2017 at Imperial College London, where they developed a novel communication-free and embarrassingly parallel biodiversity simulation algorithm for their master's thesis. In 2021, they moved to the TCM programme at the University of Helsinki to combine their computing background with atmospheric sciences, particularly climate simulation research. In their MSc, they are now working on developing improved sensitivity analysis methods for the SOSAA model.

Carlton Xavier

Atmospheric Modelling Group

Carlton Xavier graduated in May 2017 from the University of Turku with his Master of Science in Astronomy. In autumn 2016 he performed an internship in the group parallel to the writing of his thesis and started a PhD in August 2017 on the topic "Atmospheric relevance of highly oxidised organic molecules (HOM) from anthropogenic precursors and the NO3-VOC-HOM contribution".

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Martha Zaidan

Earth System Modelling Group

Martha Arbayani Zaidan is a researcher focusing on applied artificial intelligence and machine learning on big atmospheric data. His current research activities include machine learning for automating the determination process of aerosol particle formation days, information theory for improving scientific understanding of the relationship between atmospheric variables, establishing data-driven modelling for atmospheric process and air pollutants as well as developing intelligent calibrations and virtual sensors for low-cost air quality sensors.

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Putian Zhou

Cross-group collaboration

Putian Zhou joined the Earth System Modelling sub-group in 2018. His main research interest is to use the ESM model EC-Earth to investigate the emissions of dust and BVOCs over the Sahara region as well as their interactions with the west African monsoon during mid-Holocene period, when Sahara was greener than today.

Besides, he is also a developer of SOSAA, which is a 1-dimensional chemical transport model and has been widely used for various research over the forest canopy. So partly he still works in the Atmosphere Modelling Group to supervise and support the students working with SOSAA.

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Former Group Members

Jukka-Pekka Keskinen was part of the MSM group for years and performing the simulations required for the University of Helsinki to participate in the sixth phase of the coupled model intercomparison project (CMIP6). In addition to being a busy climate modeller, Jukka-Pekka is an experienced large-eddy simulation (LES) expert. He is now working at FMI, Finland.

Zhaoxin Dong, a PhD-student at the Tsinghua University in Peking, China joined the group in 2021 for a one-year scholarship on the topic " Modeling of HOMs from AVOCs and its applications in New Particle Formation".  

Quentin Bérard, a French student in applied mathematics at the Pierre and Marie Curie University, France. He joined the group for 5 months (May to September 2017) and performed his Master thesis with the LES model ASAM. The title of the thesis: "Simulating energy exchange between air and canopy at a boreal forest with ASAM" 

M.Sc. Ximeng Qi a former PhD student at Nanjing University who joined the group in 2016 for one year. His subject was ‘aerosol size distribution and new particle formation at urban site: measurement and modelling’. He is now a postdoctoral researcher at Nanjing University, China

Natalia Babkovskaia joined the group in 2011 as a postdoc. He main focus was on  atmospheric cloud physics and the use direct numerical simulations (DNS) to model the aerosol particles in the cloud area. She left the group in autumn 2016 and works nowadays in the private sector.

Anton Rusanen finished his Master thesis in the group spring 2016 and started afterwards as a PhD-student under Prof. Kulmala.

Zhou Luxi defended her PhD thesis in September 2015 with the topic "Modelling aerosol formation and precursor gases in the boundary layer". In January 2016 she moved to US to start a 2-years postdoctoral project at EPA.

Rosa Gierens finished her Master thesis in December 2015 on the topic "Understanding the evolution of the boundary layer over the Highveld, South Africa. She has started a PhD in summer 2016 at the University in Köln, Germany.

Ditte Taipale (née Mogensen) defended her Ph.D. thesis, titled "Insights into atmospheric oxidation", at University of Helsinki in May 2015. Since then she has worked as a postdoctoral researcher jointly at Department of Plant Physiology, Estonian University of Life Sciences, Tartu, Estonia and at Department of Forest Sciences, University of Helsinki, Helsinki, Finland.

Sampo Smolander is trained in Plant Ecology (M.Sc.) and Applied Mathematics (Ph.D.) and has done a 1 year PostDoc at University College London (in vegetation remote sensing). He works in vegetation modelling, boundary layer meteorology, programming, numerical algorithms, and training students in programming and scientific computing. He started a visiting scientist position at Princeton University, NJ, USA in January 2015.

Li Liao finished his PhD in the group in December 2014 with the topic "Contribution of biogenic volatile organic compounds to the formation and growth of particles in the atmosphere - from molecule cluster to cloud condensation nuclei". Afterwards the moved his professional life into the private sector.

Sanna-Liisa Sihto-Nissilä finished her PhD in the group in November 2013 with the topic "Studies on the connections between atmospheric sulphuric acid, new particle formation and cloud condensation nuclei". He is now working at Aalto University, Finland.

Chatriya Watcharapaskorn finished her Master of Science in the group in December 2011 with the topic "15-years observation of Atmospheric new particle formation in Hyytiälä and particle formation modelling by MALTE-BOX". She afterwards started as a Central Entity Allocation Analyst at Ford Motor Company (Thailand) Co., Ltd.

Qingyang He finished her Master of Science in the group in November 2011 with the topic "Modelling monoterpene emissions from boreal forest in the Southern Finland". She then started a PhD at University of Zurich, Switzerland. 

Johanna Lauros finished her PhD in the group in February 2011 with the topic "Atmospheric particle formation in spatially and temporally varying conditions". She then started a postion for the Finnish government.

Henri Vuollokoski received his PhD (“Numerical approaches to new particle formation and growth in the atmosphere”) from the University of Helsinki in January 2011. Afterwards he moved to the private sector.