Browsing Asiantuntijatarkastetut julkaisut - Refereed publications by Title

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  • Sokhi, Ranjeet S.; Moussiopoulos, Nicolas; Baklanov, Alexander; Bartzis, John; Coll, Isabelle; Finardi, Sandro; Friedrich, Rainer; Geels, Camilla; Grönholm, Tiia; Halenka, Tomas; Ketzel, Matthias; Maragkidou, Androniki; Matthias, Volker; Moldanova, Jana; Ntziachristos, Leonidas; Schäfer, Klaus; Suppan, Peter; Tsegas, George; Carmichael, Greg; Franco, Vicente; Hanna, Steve; Jalkanen, Jukka-Pekka; Velders, Guus J. M.; Kukkonen, Jaakko (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    This review provides a community’s perspective on air quality research focusing mainly on developments over the past decade. The article provides perspectives on current and future challenges as well as research needs for selected key topics. While this paper is not an exhaustive review of all research areas in the field of air quality, we have selected key topics that we feel are important from air quality research and policy perspectives. After providing a short historical overview, this review focuses on improvements in characterizing sources and emissions of air pollution, new air quality observations and instrumentation, advances in air quality prediction and forecasting, understanding interactions of air quality with meteorology and climate, exposure and health assessment, and air quality management and policy. In conducting the review, specific objectives were (i) to address current developments that push the boundaries of air quality research forward, (ii) to highlight the emerging prominent gaps of knowledge in air quality research, and (iii) to make recommendations to guide the direction for future research within the wider community. This review also identifies areas of particular importance for air quality policy. The original concept of this review was borne at the International Conference on Air Quality 2020 (held online due to the COVID 19 restrictions during 18–26 May 2020), but the article incorporates a wider landscape of research literature within the field of air quality science. On air pollution emissions the review highlights, in particular, the need to reduce uncertainties in emissions from diffuse sources, particulate matter chemical components, shipping emissions, and the importance of considering both indoor and outdoor sources. There is a growing need to have integrated air pollution and related observations from both ground-based and remote sensing instruments, including in particular those on satellites. The research should also capitalize on the growing area of low-cost sensors, while ensuring a quality of the measurements which are regulated by guidelines. Connecting various physical scales in air quality modelling is still a continual issue, with cities being affected by air pollution gradients at local scales and by long-range transport. At the same time, one should allow for the impacts from climate change on a longer timescale. Earth system modelling offers considerable potential by providing a consistent framework for treating scales and processes, especially where there are significant feedbacks, such as those related to aerosols, chemistry, and meteorology. Assessment of exposure to air pollution should consider the impacts of both indoor and outdoor emissions, as well as application of more sophisticated, dynamic modelling approaches to predict concentrations of air pollutants in both environments. With particulate matter being one of the most important pollutants for health, research is indicating the urgent need to understand, in particular, the role of particle number and chemical components in terms of health impact, which in turn requires improved emission inventories and models for predicting high-resolution distributions of these metrics over cities. The review also examines how air pollution management needs to adapt to the abovementioned new challenges and briefly considers the implications from the COVID-19 pandemic for air quality. Finally, we provide recommendations for air quality research and support for policy.
  • Kuliński, Karol; Rehder, Gregor; Asmala, Eero; Bartosova, Alena; Carstensen, Jacob; Gustafsson, Bo; Hall, Per O. J.; Humborg, Christoph; Jilbert, Tom; Jürgens, Klaus; Meier, H. E. Markus; Müller-Karulis, Bärbel; Naumann, Michael; Olesen, Jørgen E.; Savchuk, Oleg; Schramm, Andreas; Slomp, Caroline P.; Sofiev, Mikhail; Sobek, Anna; Szymczycha, Beata; Undeman, Emma (Copernicus Publ., 2022)
    Earth system dynamics
    Location, specific topography, and hydrographic setting together with climate change and strong anthropogenic pressure are the main factors shaping the biogeochemical functioning and thus also the ecological status of the Baltic Sea. The recent decades have brought significant changes in the Baltic Sea. First, the rising nutrient loads from land in the second half of the 20th century led to eutrophication and spreading of hypoxic and anoxic areas, for which permanent stratification of the water column and limited ventilation of deep-water layers made favourable conditions. Since the 1980s the nutrient loads to the Baltic Sea have been continuously decreasing. This, however, has so far not resulted in significant improvements in oxygen availability in the deep regions, which has revealed a slow response time of the system to the reduction of the land-derived nutrient loads. Responsible for that is the low burial efficiency of phosphorus at anoxic conditions and its remobilization from sediments when conditions change from oxic to anoxic. This results in a stoichiometric excess of phosphorus available for organic-matter production, which promotes the growth of N2-fixing cyanobacteria and in turn supports eutrophication. This assessment reviews the available and published knowledge on the biogeochemical functioning of the Baltic Sea. In its content, the paper covers the aspects related to changes in carbon, nitrogen, and phosphorus (C, N, and P) external loads, their transformations in the coastal zone, changes in organic-matter production (eutrophication) and remineralization (oxygen availability), and the role of sediments in burial and turnover of C, N, and P. In addition to that, this paper focuses also on changes in the marine CO2 system, the structure and functioning of the microbial community, and the role of contaminants for biogeochemical processes. This comprehensive assessment allowed also for identifying knowledge gaps and future research needs in the field of marine biogeochemistry in the Baltic Sea.
  • Kuenen, Jeroen; Dellaert, Stijn; Visschedijk, Antoon; Jalkanen, Jukka-Pekka; Super, Ingrid; Denier van der Gon, Hugo (Copernicus GmbH, 2022)
    Earth System Science Data
    This paper presents a state-of-the-art anthropogenic emission inventory developed for the European domain for an 18-year time series (2000–2017) at a 0.05◦ × 0.1◦ grid resolution, specifically designed to support air quality modelling. The main air pollutants are included: NOx , SO2, non-methane volatile organic compounds (NMVOCs), NH3, CO, PM10 and PM2.5, and also CH4. To stay as close as possible to the emissions as officially reported and used in policy assessment, the inventory uses the officially reported emission data by European countries to the UN Framework Convention on Climate Change, the Convention on Long-Range Transboundary Air Pollution and the EU National Emission Ceilings Directive as the basis where possible. Where deemed necessary because of errors, incompleteness or inconsistencies, these are replaced with or complemented by other emission data, most notably the estimates included in the Greenhouse gas Air pollution Interaction and Synergies (GAINS) model. Emissions are collected at the high sectoral level, distinguishing around 250 different sector–fuel combinations, whereafter a consistent spatial distribution is applied for Europe. A specific proxy is selected for each of the sector–fuel combinations, pollutants and years. Point source emissions are largely based on reported facility-level emissions, complemented by other sources of point source data for power plants. For specific sources, the resulting emission data were replaced with other datasets. Emissions from shipping (both inland and at sea) are based on the results from a separate shipping emission model where emissions are based on actual ship movement data, and agricultural waste burning emissions are based on satellite observations. The resulting spatially distributed emissions are evaluated against earlier versions of the dataset as well as against alternative emission estimates, which reveals specific discrepancies in some cases. Along with the resulting annual emission maps, profiles for splitting particulate matter (PM) and NMVOCs into individual components are provided, as well as information on the height profile by sector and temporal disaggregation down to the hourly level to support modelling activities. Annual grid maps are available in csv and NetCDF format
  • Guevara, Marc; Petetin, Hervé; Jorba, Oriol; Denier van der Gon, Hugo; Kuenen, Jeroen; Super, Ingrid; Jalkanen, Jukka-Pekka; Majamäki, Elisa; Johansson, Lasse; Peuch, Vincent-Henri; Pérez García-Pando, Carlos (Copernicus Publications, 2022)
    Earth system science data
    We present a European dataset of daily sector-, pollutant- and country-dependent emission adjustment factors associated with the COVID-19 mobility restrictions for the year 2020.We considered metrics traditionally used to estimate emissions, such as energy statistics or traffic counts, as well as information derived from new mobility indicators and machine learning techniques. The resulting dataset covers a total of nine emission sectors, including road transport, the energy industry, the manufacturing industry, residential and commercial combustion, aviation, shipping, off-road transport, use of solvents, and fugitive emissions from transportation and distribution of fossil fuels. The dataset was produced to be combined with the Copernicus CAMS-REG_v5.1 2020 business-as-usual (BAU) inventory, which provides high-resolution (0:1 x 0:05) emission estimates for 2020 omitting the impact of the COVID-19 restrictions. The combination of both datasets allows quantifying spatially and temporally resolved reductions in primary emissions from both criteria pollutants (NOx , SO2, nonmethane volatile organic compounds – NMVOCs, NH3, CO, PM10 and PM2:5) and greenhouse gases (CO2 fossil fuel, CO2 biofuel and CH4), as well as assessing the contribution of each emission sector and European country to the overall emission changes. Estimated overall emission changes in 2020 relative to BAU emissions were as follows: -10.5% for NOx (-602 kt), -7.8% (-260.2 Mt) for CO2 from fossil fuels, -4.7% (-808.5 kt) for CO, -4.6% (-80 kt) for SO2, -3.3% (-19.1 Mt) for CO2 from biofuels, -3.0% (-56.3 kt) for PM10, -2.5% (-173.3 kt) for NMVOCs, -2.1% (-24.3 kt) for PM2:5, -0.9% (-156.1 kt) for CH4 and -0.2% (-8.6 kt) for NH3. The most pronounced drop in emissions occurred in April (up to -32.8% on average for NOx ) when mobility restrictions were at their maxima. The emission reductions during the second epidemic wave between October and December were 3 to 4 times lower than those occurred during the spring lockdown, as mobility restrictions were generally softer (e.g. curfews, limited social gatherings). Italy, France, Spain, the United Kingdom and Germany were, together, the largest contributors to the total EU27 + UK (27 member states of the European Union and the UK) absolute emission decreases. At the sectoral level, the largest emission declines were found for aviation (-51% to -56 %), followed by road transport (-15.5% to -18.8 %), the latter being the main driver of the estimated reductions for the majority of pollutants. The collection of COVID-19 emission adjustment factors (, Guevara et al., 2022) and the CAMS-REG_v5.1 2020 BAU gridded inventory (, Kuenen et al., 2022b) have been produced in support of air quality modelling studies.
  • Partanen, Tero M.; Sofiev, Mikhail (Copernicus Publ., 2022)
    Natural hazards and earth system sciences
    This paper presents a phenomenological framework for forecasting the area-integrated fire radiative power from wildfires. In the method, a region of interest is covered with a regular grid, whose cells are uniquely and independently parameterized with regard to the fire intensity according to (i) the fire incidence history, (ii) the retrospective meteorological information, and (iii) remotely sensed hightemporal-resolution fire adiative power taken together with (iv) consistent cloud mask data. The parameterization is realized by fitting the predetermined functions for diurnal and annual profiles of fire radiative power to the remote-sensing observations. After the parametrization, the input for the fire radiative power forecast is the meteorological data alone, i.e. the weather forecast. The method is tested retrospectively for south-central African savannah areas with the grid cell size of 1.5◦ × 1.5◦. The input data included ECMWF ERA5 meteorological reanalysis and SEVIRI/MSG (Spinning Enhanced Visible and Infra-Red Imager on board Meteosat Second Generation) fire radiative power and cloud mask data. It has been found that in the areas with a large number of wildfires regularly ignited on a daily basis during dry seasons from year to year, the temporal fire radiative power evolution is quite predictable, whereas the areas with irregular fire behaviour, predictability was low. The predictive power of the method is demonstrated by comparing the predicted fire radiative power patterns and fire radiative energy values against the corresponding remote-sensing observations. The current method showed good skills for the considered African regions and was useful in understanding the challenges in predicting the wildfires in a more general case.
  • Reckermann, Marcus; Omstedt, Anders; Soomere, Tarmo; Aigars, Juris; Akhtar, Naveed; Bełdowska, Magdalena; Bełdowski, Jacek; Cronin, Tom; Czub, Michał; Eero, Margit; Hyytiäinen, Kari Petri; Jalkanen, Jukka-Pekka; Kiessling, Anders; Kjellström, Erik; Kuliński, Karol; Larsén, Xiaoli Guo; McCrackin, Michelle; Meier, H. E. Markus; Oberbeckmann, Sonja; Parnell, Kevin; Pons-Seres de Brauwer, Cristian; Poska, Anneli; Saarinen, Jarkko; Szymczycha, Beata; Undeman, Emma; Wörman, Anders; Zorita, Eduardo (Copernicus GmbH, 2022)
    Earth System Dynamics
    Coastal environments, in particular heavily populated semi-enclosed marginal seas and coasts like the Baltic Sea region, are strongly affected by human activities. A multitude of human impacts, including climate change, affect the different compartments of the environment, and these effects interact with each other. As part of the Baltic Earth Assessment Reports (BEAR), we present an inventory and discussion of different human-induced factors and processes affecting the environment of the Baltic Sea region, and their interrelations. Some are naturally occurring and modified by human activities (i.e. climate change, coastal processes, hypoxia, acidification, submarine groundwater discharges, marine ecosystems, non-indigenous species, land use and land cover), some are completely human-induced (i.e. agriculture, aquaculture, fisheries, river regulations, offshore wind farms, shipping, chemical contamination, dumped warfare agents, marine litter and microplastics, tourism, and coastal management), and they are all interrelated to different degrees. We present a general description and analysis of the state of knowledge on these interrelations. Our main insight is that climate change has an overarching, integrating impact on all of the other factors and can be interpreted as a background effect, which has different implications for the other factors. Impacts on the environment and the human sphere can be roughly allocated to anthropogenic drivers such as food production, energy production, transport, industry and economy. The findings from this inventory of available information and analysis of the different factors and their interactions in the Baltic Sea region can largely be transferred to other comparable marginal and coastal seas in the world.
  • Tiitta, Petri; Leskinen, Ari; Kaikkonen, Ville A.; Molkoselkä, Eero O.; Mäkynen, Anssi J.; Joutsensaari, Jorma; Calderon, Silvia; Romakkaniemi, Sami; Komppula, Mika (Copernicus publications, 2022)
    Atmospehric measurement techniques
    Upon a new measurement technique, it is possible to sharpen the determination of microphysical properties of cloud droplets using high resolving power imaging. The shape, size, and position of each particle inside a welldefined, three-dimensional sample volume can be measured with holographic methods without assumptions of particle properties. In situ cloud measurements were carried out at the Puijo station in Kuopio, Finland, focusing on intercomparisons between cloud droplet analyzers over 2 months in September–November 2020. The novel holographic imaging instrument (ICEMET) was adapted to measure microphysical properties of liquid clouds, and these values were compared with parallel measurements of a cloud droplet spectrometer (FM-120) and particle measurements using a twininlet system. When the intercomparison was carried out during isoaxial sampling, our results showed good agreement in terms of variability between the instruments, with the averaged ratios between ICEMET and FM-120 being 0.6 ± 0.2, 1.0 ± 0.5, and 1.2 ± 0.2 for the total number concentration (Nd) of droplets, liquid water content (LWC), and median volume diameter (MVD), respectively. This agreement during isoaxial sampling was also confirmed by mutual correlation and Pearson correlation coefficients. The ICEMETobserved LWC was more reliable than FM-120 (without a swivel-head mount), which was verified by comparing the estimated LWC to measured values, whereas the twin-inlet DMPS system and FM-120 observations of Nd showed good agreement both in variability and amplitude. Field data revealed that ICEMET can detect small cloud droplets down to5 µm via geometric magnification.
  • Sillanpää, Salla; Fung, P.L; Niemi, J.V.; Kousa, A; Kangas, L; Zaidan, M.A.; Timonen, H; Kulmala, M.; Petäjä, T; Hussein, T (Finnish Environment Institute, 2022)
    Boreal environment research
    Long-term trends of ambient gaseous pollutants and particulate matter in Helsinki metropolitan area were analyzed from 1994 to 2019. Measurement data from ten monitoring stations located in different types of urban environments including traffic, urban background, rural background, and suburban area were included in this study. We analyzed gas-phase air pollutants, such as NO, NO2, NOx, O3, SO2 and CO; and for aerosol pollutants, we explored mass concentrations for particles smaller than 10 µm and 2.5 µm in diameter (PM10 and PM2.5, respectively ). In order to quantify trends in the data, we deployed a non-parametric Mann-Kendall test and Theil-Sen method. The results were compared with the regional emissions trends and changes in meteorological conditions. Our analysis indicates that SO2 and CO in all stations have decreased to values corresponding to their regional background concentration levels and their role as urban air pollutants have diminished. Our results from the Helsinki Metropolitan area during the last 25 years show that the air quality improved and all the air pollutant concentrations show a decreasing trend, except ozone. Based on our analysis of the Air Quality Index (AQI) at traffic and urban background environments, NO2 concentration, which have typically represented the health effects resulting from vehicular traffic, is rapidly decreasing also in traffic environments. The current AQI standard therefore lacks clarity on the potential health risks from other air pollutants emitted from traffic exhaust. In addition, the air quality indicators currently considered in the AQI do not represent well enough residential wood burning and the possible health outcomes from its exposure. We suggest that the current AQI should be revised in a way that new air quality parameters would be considered, which would better represent the health effects resulting from these local combustion sources.
  • Haukka, Harri (Aalto-yliopisto, 2021)
    Avaruushankkeissa energian saatavuus ja riittävyys ovat kriittisiä tekijöitä. Kun siirrymme kauemmaksi Auringosta, vähenee säteilyvuontiheys etäisyyden neliöön. Tämän vuoksi säteilyvuo Marsissa on noin 43 prosenttia säteilyvuosta Maassa. Marsin erityispiirteenä on myös kaasukehä, pölymyrskyt sekä kaasukehässä leijaileva hiekka, jotka vaikuttavat pinnalla olevan laskeutujan vastaanottamaan säteilyvuohon. Yleisimmät menetelmät sähköenergiaa tuottamiseksi mars-laskeutujissa ovat aurinkopaneelit ja radioisotooppinen lämpösähkögeneraattori (RTG). RGT tuottaa energiaa tasaisesti, riippumatta vallitsevasta säteilyvuosta. Pienempien laskeutujien kohdalla yleensä riittää aurinkopaneeleiden ja akuston yhdistelmä. Tässä työssä on kuitenkin huomioitu mahdollisuus käyttää RTG:tä osana energiantuottojärjestelmää. Hyötykuorma ja palveluelektroniikka asettavat lähtökohdat energian- ja tehontuottojärjestelmän suunnitteluun. Tässä täytyy ottaa huomioon paitsi edellä mainittujen yksityiskohtaiset sähköiset vaatimukset, niin myös laskeutujan mukanaan tuomat massa- ja tilarajoitukset. MetNet-laskeutuja on suhteellisen pieni ja rajoittaa mm. akuston ja käytettävissä olevien aurinkopaneeleiden sekä RTG:n ominaisuuksia. Työssä kehitetty optimointityökalu antaa käytännössä rajattoman mahdollisuuden muokata energiajärjestelmän osien kokonaisuutta, mutta laskeutujan asettamien rajoituksien vuoksi, emme simuloi epärealistisia vaihtoehtoja. Optimointityökalu kehitettiin kahdessa vaiheessa. Ensin MS Excelillä, jonka avulla määriteltiin realistiset lähtökohdat mm. aurinkopaneeleiden ja akkujen määräksi sekä tarkasteltiin staattista toimintatilaa eri säteilyvuontiheyksillä ja alijärjestelmien hyötysuhteilla. Toiseksi Pythonilla, joka sisältää kaikki Excel-työkalun ominaisuudet. Tällöin voimme tarkastella järjestelmän toimintaa halutulla ajanjaksolla sekä muuttuvalla säteilyvuontiheydellä mihin vuorokauden ja vuodenaikaan tahansa. Marsin pinnalla sijaitsevien laitteiden täytyy toimia täysin autonomisesti. Tällöin energian saatavuus ja sen optimoitu käyttö ovat tärkeitä. Laskeutujan palveluelektroniikan pitää pystyä toimimaan myös ei-optimaalisessa tilanteessa ja tarvittaessa keskeyttää tieteelliset toiminnot. Näitä operaatioita ohjataan ns. syklogrammeilla, eli etukäteen ohjelmoiduilla toimintasuunnitelmilla, joita laskeutujan tietokone toteuttaa tarpeen mukaan. Työssä on simuloitu syklogrammeja eri toimintaolosuhteille hyödyntäen kehitettyä optimointityökalua.
  • Kozyreva, Olga V.; Pilipenko, Vyacheslav A.; Marshalko, Elena E.; Sokolova, Elena Yu.; Dobrovolsky, Mikhail N. (MDPI AG, 2022)
    Applied sciences
    The influence of space factors on technological systems in the Arctic (power transmission lines, oil/gas pipelines) has become critically important. To examine in depth these effects, an archive of digital 1 min data from Soviet/Russian magnetic stations deployed along the Arctic coast was created, starting from 1983 to the present. All data from various sources were converted to daily files in standard IAGA-2002 format and supplemented with quick-look magnetograms. Some of these data are included already in the existing world magnetic field databases, but not all. Examples of disturbances known to excite intense geomagnetically induced currents in power transmission lines were presented: irregular Pi3 pulsations and magnetic perturbation events. The database was augmented with the global 3D model of the Earth’s conductivity structure. The given example showed how the combined usage of the geomagnetic field database and the conductivity model enables one to synthesize the geoelectric field response to geomagnetic variations, and to assess the distortions of the pipeline-soil potential. To determine regions most susceptible to geomagnetic hazard, a map with normalized telluric fields was created for a uniform sinusoidally varying magnetic disturbance. This map showed that the largest electrotelluric potentials and field are induced in regions with a high resistivity (e.g., Kola Peninsula and Ural Mountains). This database can be also a useful support for space missions in the magnetosphere. The database is publicly available on the anonymous FTP site.
  • Sebastian, Mathew; Kompalli, Sobhan Kumar; Kumar, Vasudevan Anil; Jose, Sandhya; Babu, S. Suresh; Pandithurai, Govindan; Singh, Sachchidanand; Hooda, Rakesh K.; Soni, Vijay K.; Pierce, Jeffrey R.; Vakkari, Ville; Asmi, Eija; Westervelt, Daniel M.; Hyvärinen, Antti-Pekka; Kanawade, Vijay P. (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    Atmospheric new particle formation (NPF) is a crucial process driving aerosol number concentrations in the atmosphere; it can significantly impact the evolution of atmospheric aerosol and cloud processes. This study analyses at least 1 year of asynchronous particle number size distributions from six different locations in India. We also analyze the frequency of NPF and its contribution to cloud condensation nuclei (CCN) concentrations. We found that the NPF frequency has a considerable seasonal variability. At the measurement sites analyzed in this study, NPF frequently occurs in March–May (pre-monsoon, about 21 % of the days) and is the least common in October–November (post-monsoon, about 7 % of the days). Considering the NPF events in all locations, the particle formation rate (JSDS) varied by more than 2 orders of magnitude (0.001–0.6 cm−3s−1) and the growth rate between the smallest detectable size and 25 nm (GRSDS-25 nm) by about 3 orders of magnitude (0.2–17.2 nm h−1). We found that JSDS was higher by nearly 1 order of magnitude during NPF events in urban areas than mountain sites. GRSDS did not show a systematic difference. Our results showed that NPF events could significantly modulate the shape of particle number size distributions and CCN concentrations in India. The contribution of a given NPF event to CCN concentrations was the highest in urban locations (4.3 × 103cm−3 per event and 1.2 × 103cm−3 per event for 50 and 100 nm, respectively) as compared to mountain background sites (2.7 × 103cm−3 per event and 1.0 × 103cm−3 per event, respectively). We emphasize that the physical and chemical pathways responsible for NPF and factors that control its contribution to CCN production require in situ field observations using recent advances in aerosol and its precursor gaseous measurement techniques.
  • Kuula, Joel; Timonen, Hilkka; Niemi, Jarkko V.; Manninen, Hanna E.; Rönkkö, Topi; Hussein, Tareq; Fung, Pak Lun; Tarkoma, Sasu; Laakso, Mikko; Saukko, Erkka; Ovaska, Aino; Kulmala, Markku; Karppinen, Ari; Johansson, Lasse; Petäjä, Tuukka (Copernicus GmbH, 2022)
    Atmospheric Chemistry and Physics
    As evidence of adverse health effects due to air pollution continues to increase, the World Health Organization (WHO) recently published its latest edition of the global air quality guidelines (World Health Organization, 2021). Although not legally binding, the guidelines aim to provide a framework in which policymakers can combat air pollution by formulating evidence-based air quality management strategies. In the light of this, the European Union has stated its intent to revise the current ambient air quality directive (2008/50/EC) to more closely resemble the newly published WHO guidelines (European Commission, 2020). This article provides an informed opinion on selected features of the air quality directive that we believe would benefit from a reassessment. The selected features include discussion about (1) air quality sensors as a part of a hierarchical observation network, (2) the number of minimum sampling points and their siting criteria, and (3) new target air pollution parameters for future consideration.
  • Luo, Yuanyuan; Garmash, Olga; Li, Haiyan; Graeffe, Frans; Praplan, Arnaud P.; Liikanen, Anssi; Zhang, Yanjun; Meder, Melissa; Peräkylä, Otso; Pẽnuelas, Josep; Yáñez-Serrano, Ana María; Ehn, Mikael (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    Diterpenes (C20H32) are biogenically emitted volatile compounds that only recently have been observed in ambient air. They are expected to be highly reactive, and their oxidation is likely to form condensable vapors. However, until now, no studies have investigated gas-phase diterpene oxidation. In this paper, we explored the ozonolysis of a diterpene, ent-kaurene, in a simulation chamber. Using state-of-the-art mass spectrometry, we characterized diterpene oxidation products for the first time, and we identified several products with varying oxidation levels, including highly oxygenated organic molecules (HOM), monomers, and dimers. The most abundant monomers measured using a nitrate chemical ionization mass spectrometer were C19H28O8 and C20H30O5, and the most abundant dimers were C38H60O6 and C39H62O6. The exact molar yield of HOM from kaurene ozonolysis was hard to quantify due to uncertainties in both the kaurene and HOM concentrations, but our best estimate was a few percent, which is similar to values reported earlier for many monoterpenes. We also monitored the decrease in the gas-phase oxidation products in response to an increased condensation sink in the chamber to deduce their affinity to condense. The oxygen content was a critical parameter affecting the volatility of products, with four to five O atoms needed for the main monomeric species to condense onto 80 nm particles. Finally, we report on the observed fragmentation and clustering patterns of kaurene in a Vocus proton-transferreaction time-of-flight mass spectrometer. Our findings highlight similarities and differences between diterpenes and smaller terpenes during their atmospheric oxidation, but more studies on different diterpenes are needed for a broader view of their role in atmospheric chemistry.
  • Lacagnina, Carlo; Doblas-Reyes, Francisco; Larnicol, Gilles; Buontempo, Carlo; Obregón, André; Costa-Surós, Montserrat; San-Martín, Daniel; Bretonnière, Pierre-Antoine; Polade, Suraj D.; Romanova, Vanya; Putero, Davide; Serva, Federico; Llabrés-Brustenga, Alba; Pérez, Antonio; Cavaliere, Davide; Membrive, Olivier; Steger, Christian; Pérez-Zanón, Núria; Cristofanelli, Paolo; Madonna, Fabio; Rosoldi, Marco; Riihelä, Aku; Díez, Markel García (Ubiquity Press, Ltd., 2022)
    Data Science Journal
    Data from a variety of research programmes are increasingly used by policy makers, researchers, and private sectors to make data-driven decisions related to climate change and variability. Climate services are emerging as the link to narrow the gap between climate science and downstream users. The Global Framework for Climate Services (GFCS) of the World Meteorological Organization (WMO) offers an umbrella for the development of climate services and has identified the quality assessment, along with its use in user guidance, as a key aspect of the service provision. This offers an extra stimulus for discussing what type of quality information to focus on and how to present it to downstream users. Quality has become an important keyword for those working on data in both the private and public sectors and significant resources are now devoted to quality management of processes and products. Quality management guarantees reliability and usability of the product served, it is a key element to build trust between consumers and suppliers. Untrustworthy data could lead to a negative economic impact at best and a safety hazard at worst. In a progressive commitment to establish this relation of trust, as well as providing sufficient guidance for users, the Copernicus Climate Change Service (C3S) has made significant investments in the development of an Evaluation and Quality Control (EQC) function. This function offers a homogeneous user-driven service for the quality of the C3S Climate Data Store (CDS). Here we focus on the EQC component targeting the assessment of the CDS datasets, which include satellite and in-situ observations, reanalysis, climate projections, and seasonal forecasts. The EQC function is characterised by a two-tier review system designed to guarantee the quality of the dataset information. While the need of assessing the quality of climate data is well recognised, the methodologies, the metrics, the evaluation framework, and how to present all this information to the users have never been developed before in an operational service, encompassing all the main climate dataset categories. Building the underlying technical solutions poses unprecedented challenges and makes the C3S EQC approach unique. This paper describes the development and the implementation of the operational EQC function providing an overarching quality management service for the whole CDS data.
  • Kruglyakov, Mikhail; Kuvshinov, Alexey; Marshalko, Elena (American Geophysical Union, 2022)
    Space weather: the international journal of research and applications
    We present a methodology that allows researchers to simulate in real time the spatiotemporal dynamics of the ground electric field (GEF) in a given 3-D conductivity model of the Earth based on continuously augmented data on the spatiotemporal evolution of the inducing source. The formalism relies on the factorization of the source by spatial modes (SM) and time series of respective expansion coefficients and exploits precomputed GEF kernels generated by corresponding SM. To validate the formalism, we invoke a high-resolution 3-D conductivity model of Fennoscandia and consider a realistic source built using the Spherical Elementary Current Systems (SECS) method as applied to magnetic field data from the International Monitor for Auroral Geomagnetic Effect network of observations. The factorization of the SECS-recovered source is then performed using the principal component analysis. Eventually, we show that the GEF computation at a given time instant on a 512 × 512 grid requires less than 0.025 s provided that GEF kernels due to pre-selected SM are computed in advance. Taking the 7–8 September 2017 geomagnetic storm as a space weather event, we show that real-time high-resolution 3-D modeling of the GEF is feasible. This opens a practical opportunity for GEF (and eventually geomagnetically induced currents) nowcasting and forecasting.
  • Ström, Johan; Svensson, Jonas; Honkanen, Henri; Asmi, Eija; Dkhar, Nathaniel B.; Tayal, Shresth; Sharma, Ved P.; Hooda, Rakesh; Meinander, Outi; Leppäranta, Matti; Jacobi, Hans-Werner; Lihavainen, Heikki; Hyvärinen, Antti (BioOne, 2022)
    Snow darkening by deposited light-absorbing particles (LAP) accelerates snowmelt and shifts the snow meltout date (MOD). Here, we present a simple approach to estimate the snow albedo variability due to LAP deposition and test this method with data for 2 seasons (February–May 2016 and December 2016–June 2017) at a high-altitude valley site in the Central Himalayas, India. We derive a parameterization for the snow albedo that only depends on the daily observations of average ambient temperature and change in snow depth, as well as an assumed average concentration of LAP in snow precipitation. Linear regression between observed and parameterized albedo for the base case assuming an equivalent elemental carbon concentration ½ECeq of 100 ng g–1 in snow precipitation yields a slope of 0.75 and a Pearson correlation coefficient r 2 of 0.76. However, comparing the integrated amount of shortwave radiation absorbed during the winter season using observed albedo versus base case albedo resulted in rather small differences of 11% and 4% at the end of Seasons 1 and 2, respectively.The enhanced energy absorbed due to LAP at the end of the 2 seasons for the base case scenario (assuming an ½ECeq of 100 ng g–1 in snow precipitation) was 40% and 36% compared to pristine snow. A numerical evaluation with different assumed ½ECeq in snow precipitation suggests that the relative sensitivity of snow albedo to changes in ½ECeq remains rather constant for the 2 seasons. Doubling ½ECeq augments the absorption by less than 20%, highlighting that the impact on a MOD is small even for a doubling of average LAP in snow precipitation.
  • Ahola, Jaakko; Raatikainen, Tomi; Alper, Muzaffer Ege; Keskinen, Jukka-Pekka; Kokkola, Harri; Kukkurainen, Antti; Lipponen, Antti; Liu, Jia; Nordling, Kalle; Partanen, Antti-Ilari; Romakkaniemi, Sami; Räisänen, Petri; Tonttila, Juha; Korhonen, Hannele (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    The number of cloud droplets formed at the cloud base depends on both the properties of aerosol particles and the updraft velocity of an air parcel at the cloud base. As the spatial scale of updrafts is too small to be resolved in global atmospheric models, the updraft velocity is commonly parameterised based on the available turbulent kinetic energy. Here we present alternative methods through parameterising updraft velocity based on high-resolution large-eddy simulation (LES) runs in the case of marine stratocumulus clouds. First we use our simulations to assess the accuracy of a simple linear parameterisation where the updraft velocity depends only on cloud top radiative cooling. In addition, we present two different machine learning methods (Gaussian rocess emulation and random forest) that account for different boundary layer conditions and cloud properties. We conclude that both machine learning parameterisations reproduce the LES-based updraft velocities at about the same accuracy, while the simple approach employing radiative cooling only produces on average lower coefficient of determination and higher root mean square error values. Finally, we apply these machine learning methods to find the key parameters affecting cloud base updraft velocities.
  • Fatahi, Yalda; Kouznetsov, Rostislav; Sofiev, Mikhail (Copernicus Publ., 2021)
    Geoscientific model development
    This study quantifies the impact of emission changes during public holidays on air quality (AQ) and anal anayses the added value of accounting for the holidays in AQ modelling. Spatial and temporal distributions of atmosphericconcentrations of the major air pollutants (the main focus was on NO2, but we also included O3, CO, PM2.5, and SO2) were considered at the European scale for all public holi days of 2018. Particular attention was paid to the events with the most pronounced continental- or regional-scale impact: Christmas and New Year, Easter, May Day vacations, and the last days of Ramadan. The simulations were performed with the chemistry transport model SILAM v.5.7 (System for Integrated modeLling of Atmospheric coMposition). Three model runs were made: the baseline with no treatment of holidays, the run considering holidays as Sundays, and the run forcing 80 % reduction in emissions during holidays for the weekday-sensitive sectors. The emission scaling was applied on a country basis. The model predictions were compared with in situ observations collected by the European Environment Agency. The experiment showed that even conservative treatment of official holidays has a large positive impact on NOx (up to 30 % of reduction in the bias inhomogene ity during the holiday days) and improves the CO, PM2.5, and O3 predictions. In many cases, the sensitivity simulations suggested a greater emission reduction than the level of Sundays. An individual consideration of the holiday events in different countries may further improve their representation in the models: specific diurnal pattern of emissions, additional emission due to fireworks, and different driving patterns.
  • Raatikainen, Tomi; Prank, Marje; Ahola, Jaakko; Kokkola, Harri; Tonttila, Juha; Romakkaniemi, Sami (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    Shallow marine mixed-phase clouds are important for the Earth’s radiative balance, but modelling their formation and dynamics is challenging. These clouds depend on boundary layer turbulence and cloud top radiative cooling, which is related to the cloud phase. The fraction of frozen droplets depends on the availability of suitable ice-nucleating particles (INPs), which initiate droplet freezing. While mineral dust is the dominating INP type in most regions, high-latitude boundary layer clouds can be dependent on local marine INP emissions, which are often related to biogenic sources including phytoplankton. Here we use high resolution large eddy simulations to examine the potential effects of marine emissions on boundary layer INP concentrations and their effects on clouds. Surface emissions have a direct effect on INP concentration in a typical well-mixed boundary layer whereas a steep inversion can block the import of background INPs from the free troposphere. The importance of the marine source depends on the background INP concentration, so that marine INP emissions become more important with lower background INP concentrations. For the INP budget it is also important to account for INP recycling. Finally, with the high-resolution model we show how ice nucleation hotspots and high INP concentrations are focused on updraught regions. Our results show that marine INP emissions contribute directly to the boundary layer INP budget and therefore have an influence on mixed-phase clouds.