Editor(s): V.-M. Kerminen, M. Heimann, D. Spracklen, T. Laurila, A. Ding, and I. SalmaMore information
The Pan-Eurasian Experiment (PEEX) is a multi-disciplinary, multi-scale and multi-component research infrastructure and capacity building programme. The PEEX originated from a bottom-up approach by the science community and is aimed at resolving the major uncertainties in Earth system science and global sustainability issues concerning the Arctic and boreal Pan-Eurasian regions as well as China. The PEEX solves interlinked global, grand challenges influencing human well-being and societies in northern Eurasia and China, by establishing and maintaining long-term, coherent and coordinated research activities as well as continuous, comprehensive research and educational infrastructures. The scientific issues covered by PEEX include climate change, air quality, biodiversity loss, chemicalisation, food supply, fresh water and the use of natural resources through mining, industry, energy production and transport. Our approach is integrative and interdisciplinary, recognizing the important role of the Arctic and boreal ecosystems in the Earth system.
Tuukka Petäjä, Ella-Maria Duplissy, Ksenia Tabakova, Julia Schmale, Barbara Altstädter, Gerard Ancellet, Mikhail Arshinov, Yurii Balin, Urs Baltensperger, Jens Bange, Alison Beamish, Boris Belan, Antoine Berchet, Rossana Bossi, Warren R. L. Cairns, Ralf Ebinghaus, Imad El Haddad, Beatriz Ferreira-Araujo, Anna Franck, Lin Huang, Antti Hyvärinen, Angelika Humbert, Athina-Cerise Kalogridis, Pavel Konstantinov, Astrid Lampert, Matthew MacLeod, Olivier Magand, Alexander Mahura, Louis Marelle, Vladimir Masloboev, Dmitri Moisseev, Vaios Moschos, Niklas Neckel, Tatsuo Onishi, Stefan Osterwalder, Aino Ovaska, Pauli Paasonen, Mikhail Panchenko, Fidel Pankratov, Jakob B. Pernov, Andreas Platis, Olga Popovicheva, Jean-Christophe Raut, Aurélie Riandet, Torsten Sachs, Rosamaria Salvatori, Roberto Salzano, Ludwig Schröder, Martin Schön, Vladimir Shevchenko, Henrik Skov, Jeroen E. Sonke, Andrea Spolaor, Vasileios K. Stathopoulos, Mikko Strahlendorff, Jennie L. Thomas, Vito Vitale, Sterios Vratolis, Carlo Barbante, Sabine Chabrillat, Aurélien Dommergue, Konstantinos Eleftheriadis, Jyri Heilimo, Kathy S. Law, Andreas Massling, Steffen M. Noe, Jean-Daniel Paris, André S. H. Prévôt, Ilona Riipinen, Birgit Wehner, Zhiyong Xie, and Hanna K. Lappalainen
The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. Here we summarize initial results from our integrative project exploring the Arctic environment and pollution to deliver data products, metrics, and indicators for stakeholders.
We found a positive particle matter-mixing layer height feedback at three observation platforms at the 325 m Beijing meteorology tower, which is characterized by a shallower mixing layer height and a higher particle matter concentration. Measurements of solar radiation, aerosol chemical composition, meteorology parameters, trace gases and turbulent kinetic energy (TKE) could explain the feedback mechanism to some extent.
Satellite observations combined with in situ measurements demonstrate that increased inorganic aerosol fractions of NO2 and SO2 contribute to air pollution and frequently occurring haze in China from 1980 to 2010. Currently, the reduction of nitrate, sulfate and their precursor gases would contribute towards better visibility in China.
Katri Leino, Janne Lampilahti, Pyry Poutanen, Riikka Väänänen, Antti Manninen, Stephany Buenrostro Mazon, Lubna Dada, Anna Franck, Daniela Wimmer, Pasi P. Aalto, Lauri R. Ahonen, Joonas Enroth, Juha Kangasluoma, Petri Keronen, Frans Korhonen, Heikki Laakso, Teemu Matilainen, Erkki Siivola, Hanna E. Manninen, Katrianne Lehtipalo, Veli-Matti Kerminen, Tuukka Petäjä, and Markku Kulmala
This study presents airborne observations of particles, starting from 1.5 nm in diameter, above the boreal forest from 100 m up to 2700 m. The aim was to study the extent of NPF and likely places for nucleation. We found that the highest concentrations of 1.5–3 nm particles were above the forest canopy top on NPF event mornings, and the concentration decreased with increasing altitude. This would indicate the importance of gaseous precursors from vegetation for NPF processes in this area.
We consider the budget of turbulent kinetic energy (TKE) in stably stratified flows. TKE is generated by velocity shear, then partially converted to potential energy, but basically cascades towards very small eddies and dissipates into heat. The TKE dissipation rate is vital for comprehending and modelling turbulent flows in geophysics, astrophysics, and engineering. Until now its dependence on static stability remained unclear. We define it theoretically and validate against experimental data.
Michael Boy, Erik S. Thomson, Juan-C. Acosta Navarro, Olafur Arnalds, Ekaterina Batchvarova, Jaana Bäck, Frank Berninger, Merete Bilde, Zoé Brasseur, Pavla Dagsson-Waldhauserova, Dimitri Castarède, Maryam Dalirian, Gerrit de Leeuw, Monika Dragosics, Ella-Maria Duplissy, Jonathan Duplissy, Annica M. L. Ekman, Keyan Fang, Jean-Charles Gallet, Marianne Glasius, Sven-Erik Gryning, Henrik Grythe, Hans-Christen Hansson, Margareta Hansson, Elisabeth Isaksson, Trond Iversen, Ingibjorg Jonsdottir, Ville Kasurinen, Alf Kirkevåg, Atte Korhola, Radovan Krejci, Jon Egill Kristjansson, Hanna K. Lappalainen, Antti Lauri, Matti Leppäranta, Heikki Lihavainen, Risto Makkonen, Andreas Massling, Outi Meinander, E. Douglas Nilsson, Haraldur Olafsson, Jan B. C. Pettersson, Nønne L. Prisle, Ilona Riipinen, Pontus Roldin, Meri Ruppel, Matthew Salter, Maria Sand, Øyvind Seland, Heikki Seppä, Henrik Skov, Joana Soares, Andreas Stohl, Johan Ström, Jonas Svensson, Erik Swietlicki, Ksenia Tabakova, Throstur Thorsteinsson, Aki Virkkula, Gesa A. Weyhenmeyer, Yusheng Wu, Paul Zieger, and Markku Kulmala
The Nordic Centre of Excellence CRAICC (Cryosphere–Atmosphere Interactions in a Changing Arctic Climate), funded by NordForsk in the years 2011–2016, is the largest joint Nordic research and innovation initiative to date and aimed to strengthen research and innovation regarding climate change issues in the Nordic region. The paper presents an overview of the main scientific topics investigated and provides a state-of-the-art comprehensive summary of what has been achieved in CRAICC.
Timo Vihma, Petteri Uotila, Stein Sandven, Dmitry Pozdnyakov, Alexander Makshtas, Alexander Pelyasov, Roberta Pirazzini, Finn Danielsen, Sergey Chalov, Hanna K. Lappalainen, Vladimir Ivanov, Ivan Frolov, Anna Albin, Bin Cheng, Sergey Dobrolyubov, Viktor Arkhipkin, Stanislav Myslenkov, Tuukka Petäjä, and Markku Kulmala
The Arctic marine climate system, ecosystems, and socio-economic systems are changing rapidly. This calls for the establishment of a marine Arctic component of the Pan-Eurasian Experiment (MA-PEEX), for which we present a plan. The program will promote international collaboration; sustainable marine meteorological, sea ice, and oceanographic observations; advanced data management; and multidisciplinary research on the marine Arctic and its interaction with the Eurasian continent.
Our paper provides an automatic method to classify new particle formation events into four classes based on the accompanying air ion concentrations. The method is applied to 10 years of data measured within the SMEAR II station and was capable of eliminating the undefined class as well as defining the start, peak and end times of a regional event by monitoring the initial steps of cluster formation. Our method can be modified and applied to different locations where particle formation occurs.
Ekaterina Ezhova, Ilona Ylivinkka, Joel Kuusk, Kaupo Komsaare, Marko Vana, Alisa Krasnova, Steffen Noe, Mikhail Arshinov, Boris Belan, Sung-Bin Park, Jošt Valentin Lavrič, Martin Heimann, Tuukka Petäjä, Timo Vesala, Ivan Mammarella, Pasi Kolari, Jaana Bäck, Üllar Rannik, Veli-Matti Kerminen, and Markku Kulmala
Understanding the connections between aerosols, solar radiation and photosynthesis in terrestrial ecosystems is important for estimates of the CO2 balance in the atmosphere. Atmospheric aerosols and clouds influence solar radiation. In this study, we quantify the aerosol effect on solar radiation in boreal forests and study forest ecosystems response to this change in the radiation conditions. The analysis is based on atmospheric observations from several remote stations in Eurasian forests.
This study reports on the urban heat island (UHI) in a typical Arctic city in winter. Using in situ observations, remote sensing data and modeling, we show that the urban temperature anomaly reaches up to 11 K with a mean value of 1.9 K. At least 50 % of this anomaly is caused by the UHI effect, driven mostly by heating. The rest is created by natural microclimatic variability over the hilly terrain. This is a strong argument in support of energy efficiency measures in the Arctic cities.
A good knowledge of black carbon (BC) emissions from open biomass burning (BB) is an important prerequisite for reliable climate predictions, especially in the Arctic. This paper introduces a method to constrain a regional budget of BB BC emissions using satellite measurements of the absorption and extinction optical depths and evaluates its potential application in a large Siberian region.
Pertti Hari, Steffen Noe, Sigrid Dengel, Jan Elbers, Bert Gielen, Veli-Matti Kerminen, Bart Kruijt, Liisa Kulmala, Anders Lindroth, Ivan Mammarella, Tuukka Petäjä, Guy Schurgers, Anni Vanhatalo, Markku Kulmala, and Jaana Bäck
The development of eddy-covariance measurements of ecosystem CO2 fluxes began a new era in the field studies of photosynthesis. The interpretation of the very variable CO2 fluxes in evergreen forests has been problematic especially in seasonal transition times. We apply two theoretical needle-level equations and show they can predict photosynthetic CO2 flux between the atmosphere and Scots pine forests. This has strong implications for the interpretation of the global change and boreal forests.
In this study we simulate the HOM concentrations and discuss their roles in NPF at a remote boreal forest site in Finland and a suburban site in eastern China. We found that sulfuric acid and HOM organonitrate concentrations in the gas phase are significantly higher but other HOM monomers and dimers from monoterpene oxidation are lower in eastern China. This study highlights the need for molecular-scale measurements in improving the understanding of NPF mechanisms in polluted areas.
Our project describes the feasibility of implementing particle number emissions taken from the GAINS model in global climate modeling through a simulation with the ECHAM-HAM global climate model. The results from the simulations have important implications regarding modeled particle number concentrations and future climate effects. Our findings represent an important starting point for further simulations concerning climate effects derived from anthropogenic particle emissions on a global scale.
An optimized segregation method is applied to estimate light absorption of brown carbon (BrC) in Nanjing. This study highlights the considerable contribution of BrC to light absorption in the Yangtze River Delta region, China, and depicts its long-term profile in this region for the first time. Lagrangian modeling and the chemical signature observed at the site suggested that open biomass burning and residential emissions are the dominant sources influencing BrC in the two highest BrC seasons.
The cryosphere of the Earth overlaps with the atmosphere, hydrosphere and lithosphere over vast areas with temperatures below zero C and pronounced H2O phase changes. The cryosphere plays the role of a global thermostat; however, the processes related to the cryosphere attract insufficient attention from research communities. We call attention to crucial importance of cryogenic anomalies, which make the Earth atmosphere and the entire Earth system unique.
Aerosol optical properties (AOPs) were measured at SORPES, a regional background station in Nanjing, China from June 2013 to May 2015. The aerosol was highly scattering. The single-scattering albedo in Nanjing appears to be slightly higher than at several other sites. The data do not suggest any significant contribution to absorption by brown carbon. The sources of high values are mainly in eastern China. During pollution episodes, pollutant concentrations increased gradually but decreased fast.
Highly time and chemically resolved submicron aerosol properties were characterized online for the first time in a high-altitude site (Qomolangma station, 4276 m a.s.l.) in the northern Himalayas by using the Aerodyne HR-ToF-AMS. Biomass burning plumes were frequently observed and the dynamic processes (emissions, transport, and chemical processing) were characterized. The source and chemical composition of organic aerosol were further elucidated using positive matrix factorization analysis.
Emissions of volatile organic compounds (VOCs) have impact to air quality, human health and climate. We investigated the development of VOC exchange in a boreal forest between April and June 2013. VOC exchange and diversity increased towards summer, but over 75 % of the biogenic net exchange was driven by methanol, monoterpenes and acetone only. The boreal forest emitted less than 0.2 % carbon in form of VOCs in relation to the carbon uptake.
In this study we used the NanoMap method by applying back trajectories and particle number size distribution in different rural sites in China to evaluate the spatial distribution of NPF events and their occurrence probability. We found difference in the horizontal spatial distribution of new particle source areas was connected to typical meteorological conditions. The horizontal extent of NPF reached to larger than 500 km at two sites, favoured by the fast transport of northwesterly air masses.
We analysed a 20-year-long dataset collected in a Finnish boreal forest at SMEAR II station to investigate the frequency and strength of ozone depletion events. We could identify a number of ozone depletion events that lasted for more than 3 h, mainly in the autumn and winter months. Their occurrence was likely related to the formation of a low mixing layer under the conditions of low temperatures, low wind speeds, high relative humidities and limited intensity of solar radiation.
We developed a theory on the seasonal behaviour of photosynthesis in natural conditions and tested the theory with intensive measurements. Light, temperature, water vapor and CO2 concentration explained the daily variation in photosynthesis, and the physiological state of the photosynthetic machinery explained the annual pattern of photosynthesis. The theory explained about 95 % of the variance of photosynthesis measured with chambers in the field in northern Finland.
Eugene F. Mikhailov, Svetlana Mironova, Gregory Mironov, Sergey Vlasenko, Alexey Panov, Xuguang Chi, David Walter, Samara Carbone, Paulo Artaxo, Martin Heimann, Jost Lavric, Ulrich Pöschl, and Meinrat O. Andreae
Extrapolation of the particle formation rates from one measured larger size (e.g., 7 nm) to smaller sizes (e.g., 3 nm) based on simplified growth-scavenging dynamics works fairly well to estimate mean daily formation rates, but it fails to predict the time evolution of the particle population. This points to the challenges in predicting atmospheric nucleation rates for locations where the particle growth and loss rates are size- and time-dependent.
The VOC emission inventory has large uncertainties. An updated VOC emission inventory of vehicles in China was developed based on a set of state-of-the-art methods and big data. Exhausts and evaporation were taken into account. Our results narrowed the gap between inventories and the real emissions. Detailed speciation reveals the chemical characteristics of emissions, which has the potential to improve the understanding of atmospheric chemical processes in polluted regions.
Boreal Siberia is a unique region with severe wildfire activity which is little studied today. We employ unique ground-based observations of major biomass burning products obtained during TRanscontinental Observations Into the Chemistry of the Atmosphere (TROICA) expedition along the Trans-Siberian Railway to provide information about chemical composition of forest fire plumes in Siberia. The results may be used in studies related to climate change and regional air quality.
Effective and efficient control of air pollution relies upon an understanding of the pollution sources. We conduct an interdisciplinary study and find that 33 % of China’s PM2.5-related premature mortality in 2010 were caused by production emission in other regions; 56 % of the mortality was related to consumption in other regions. Multilateral and multi-stage cooperation under a regional sustainable development framework is in urgent need to mitigate air pollution and related health impacts.
West Siberian peatlands occupy a large fraction of land area in the region, and yet little is known about their interaction with the atmosphere. We took the first measurements of CO2 and energy surface balances over a typical bog of West Siberian middle taiga, in the vicinity of the Mukhrino field station (Khanty–Mansiysk). The May–August study in a wet year (2015) revealed a relatively large photosynthetic sink of CO2 that was close to the high end of estimates at bog sites elsewhere.
As black carbon (BC) aerosols play an important role in the climate and environment, the size distribution of refractory BC (rBC) was investigated. On this basis, the source of rBC was further analyzed. The local traffic exhausts contributed greatly to the rBC in urban areas. However, its contribution decreased significantly in the polluted period compared to the clean period, implying the increasing contribution of other sources, e.g., coal combustion or biomass burning, in the polluted period.
In this publication we used a number of very high (10 m) resolution simulations in order to assess the circulation in a coastal mountain city under high-air-pollution conditions. We found that forcings of the valley circulation through local surface inhomogeneities can have a distinct impact on the pollution distribution in the urban area. The work serves as a proof of concept for the applied high-resolution simulations to assess pollution conditions in the urban area under the given conditions.
We studied new particle formation under clear-sky conditions in the boreal forest in southern Finland. We compared varying conditions between new particle events and nonevents. We then formulated a threshold value that separates new particle events from nonevents and reached a probability distribution for the frequency of new particle formation. This study serves as the basis for scientists aiming to improve their understanding of new particle formation.
The aerosol effects on warm cloud parameters over the Yangtze River Delta are systematically examined using multi-sensor retrievals. This study shows that the COT–CDR and CWP–CDR relationships are not unique, but are affected by atmospheric aerosol loading. CDR and cloud fraction show different behaviours for low and high AOD. Aerosol–cloud interaction (ACI) is stronger for clouds mixed with smoke aerosol than for clouds mixed with dust. Meteorological conditions play an important role in ACI.
In this paper, we analyse surface levels of benzene, toluene, non-methane hydrocarbons (NMHCs), CO, O3, SO2, NO, NO2 and meteorology measured on a mobile laboratory along the Trans-Siberian Railway from Moscow to Vladivostok in summer 2008. The main sources of benzene and toluene along the railway are revealed. The total contribution of benzene and toluene to photochemical ozone production along the Trans-Siberian Railway is determined and compared to the most abundant organic VOC – isoprene.
We present spring and summer VOC emission rate measurements from Norway spruce using an in situ gas chromatograph. Monoterpene and C4–C10 aldehyde emission rates reached maxima in July. SQT emissions increased at the end of July and in August SQT were the most abundant group. The MT emission pattern varied a lot from tree to tree and therefore emission fluxes on canopy level should be conducted for more representative measurements. However, leaf level measurements produce more reliable SQT data.
Mass spectrometric measurements commonly yield data on hundreds of variables over thousands of points in time. Refining and synthesising this “raw” data into chemical information necessitates the use of advanced, statistics-based data analysis techniques. Here we present an example of combining data dimensionality reduction (factorisation) with exploratory classification (clustering) and show that the results complement and broaden our current perspectives on aerosol chemical classification.
Multi-year observations at a coastal station in Hong Kong reveals that aerosol optical properties showed clear temporal variations according to the dominant sources of aerosols. LPDM modeling and correlation analysis gave similar signals about the freshness of aerosols during different seasons. Fresh emissions of particles from nearby cities and ship exhausts affected light optical properties and particle size in summer and aged air mass in winter caused larger variability of light extinction.
This work performed a thorough chemical characterization on the fine particulate matter (PM2.5) samples, collected during July 2015 to April 2016 across four seasons in Changzhou for the first time. In particular, an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) was deployed offline to probe the chemical properties and sources of the water-soluble fraction of organic aerosols (WSOAs).
Benzo[a]pyrene (BaP) is a toxic compound emitted from various anthropogenic sources. This study is the first attempt to evaluate all major input and output components of BaP balance in the land-use zones of the eastern district of Moscow. Based on measurements of BaP atmospheric fallout and reserves in the soils, the critical loads of BaP were calculated for different values of degradation intensity. Ecologically safe BaP levels in the soils will only be reached after many decades or centuries.
Jenni Kontkanen, Katrianne Lehtipalo, Lauri Ahonen, Juha Kangasluoma, Hanna E. Manninen, Jani Hakala, Clémence Rose, Karine Sellegri, Shan Xiao, Lin Wang, Ximeng Qi, Wei Nie, Aijun Ding, Huan Yu, Shanhu Lee, Veli-Matti Kerminen, Tuukka Petäjä, and Markku Kulmala
The concentrations of ~1–3 nm particles were investigated at nine sites around the world. Sub-3 nm particle concentrations were highest at the sites with strong anthropogenic influence. Electrically neutral particles dominated sub-3 nm particle concentrations in polluted environments and in boreal forest during spring and summer. Sub-3 nm particle concentrations were observed to be determined by the availability of precursor vapors rather than the sink caused by preexisting aerosol particles.
We discuss characteristics, sources, and size distributions of the PM1 composition and OA components in Seoul, Korea, in winter. The serious pollution observed was caused by a combination of various factors, including meteorological conditions, emissions from local primary sources, secondary formation, and transport of air masses from upwind locations. This will be very useful for enacting effective PM reduction strategies for Korea as well as for the broader northern pan-Eurasian region.
Hanna K. Lappalainen, Veli-Matti Kerminen, Tuukka Petäjä, Theo Kurten, Aleksander Baklanov, Anatoly Shvidenko, Jaana Bäck, Timo Vihma, Pavel Alekseychik, Meinrat O. Andreae, Stephen R. Arnold, Mikhail Arshinov, Eija Asmi, Boris Belan, Leonid Bobylev, Sergey Chalov, Yafang Cheng, Natalia Chubarova, Gerrit de Leeuw, Aijun Ding, Sergey Dobrolyubov, Sergei Dubtsov, Egor Dyukarev, Nikolai Elansky, Kostas Eleftheriadis, Igor Esau, Nikolay Filatov, Mikhail Flint, Congbin Fu, Olga Glezer, Aleksander Gliko, Martin Heimann, Albert A. M. Holtslag, Urmas Hõrrak, Juha Janhunen, Sirkku Juhola, Leena Järvi, Heikki Järvinen, Anna Kanukhina, Pavel Konstantinov, Vladimir Kotlyakov, Antti-Jussi Kieloaho, Alexander S. Komarov, Joni Kujansuu, Ilmo Kukkonen, Ella-Maria Duplissy, Ari Laaksonen, Tuomas Laurila, Heikki Lihavainen, Alexander Lisitzin, Alexsander Mahura, Alexander Makshtas, Evgeny Mareev, Stephany Mazon, Dmitry Matishov, Vladimir Melnikov, Eugene Mikhailov, Dmitri Moisseev, Robert Nigmatulin, Steffen M. Noe, Anne Ojala, Mari Pihlatie, Olga Popovicheva, Jukka Pumpanen, Tatjana Regerand, Irina Repina, Aleksei Shcherbinin, Vladimir Shevchenko, Mikko Sipilä, Andrey Skorokhod, Dominick V. Spracklen, Hang Su, Dmitry A. Subetto, Junying Sun, Arkady Y. Terzhevik, Yuri Timofeyev, Yuliya Troitskaya, Veli-Pekka Tynkkynen, Viacheslav I. Kharuk, Nina Zaytseva, Jiahua Zhang, Yrjö Viisanen, Timo Vesala, Pertti Hari, Hans Christen Hansson, Gennady G. Matvienko, Nikolai S. Kasimov, Huadong Guo, Valery Bondur, Sergej Zilitinkevich, and Markku Kulmala
After kick off in 2012, the Pan-Eurasian Experiment (PEEX) program has expanded fast and today the multi-disciplinary research community covers ca. 80 institutes and a network of ca. 500 scientists from Europe, Russia, and China. Here we introduce scientific topics relevant in this context. This is one of the first multi-disciplinary overviews crossing scientific boundaries, from atmospheric sciences to socio-economics and social sciences.
Laura Riuttanen, Marja Bister, Veli-Matti Kerminen, Viju O. John, Anu-Maija Sundström, Miikka Dal Maso, Jouni Räisänen, Victoria A. Sinclair, Risto Makkonen, Filippo Xausa, Gerrit de Leeuw, and Markku Kulmala
Here we show observational evidence that aerosols increase upper tropospheric humidity (UTH) via changes in the microphysics of deep convection. Using remote sensing data over the ocean east of China in summer, we show that increased aerosol loads are associated with an UTH increase of 2.2 ± 1.5 in units of relative humidity. We show that humidification of aerosols or other meteorological covariation is very unlikely to be the cause for this result indicating relevance for the global climate.
Ionising radiation is responsible for air ion production. However, minor efforts have been invested in understanding the connection of observed air ions to ionising radiation in the lower atmosphere and underlying processes therein. In this work, we analysed 4 years of ambient data collected in a Finnish boreal forest and found that gamma radiation dominates air ion production in the lower atmosphere and demonstrated clear promotion effects of the ionising radiation on air ion production.
We developed proxies for estimating the concentrations of monoterpenes and their oxidation products at a boreal forest site in Hyytiälä, Finland. The proxies for the monoterpene concentration include temperature-controlled emissions, dilution and different oxidation processes. The proxies were observed to capture the seasonal and diurnal variation of the monoterpene concentration reasonably well. Our proxies can be used in the analysis of new particle formation and growth in boreal environments.
Biologically active ultraviolet (UV) radiation is an important environmental factor, which affect human health and nature. UV radiation has a significant increase with the altitude. We propose a new method for calculating the altitude UV dependence for different types of biologically active UV radiation. The proposed method was implemented in the on-line UV tool (http://momsu.ru/uv/) for Northern Eurasia. The possible UV effects on human health were considered over Alpine zone.
We conducted a comprehensive modelling work to understand the impact of biomass burning on synoptic weather during agricultural burning season in East China. We demonstrated that the numerical model with fire emission, chemical processes, and aerosol–meteorology online coupled could reproduce the change of air temperature and precipitation induced by air pollution during this event. This study highlights the importance of including human activities in numerical-model-based weather forecast.
The PBL height retrieval from CALIOP aboard CALIPSO can significantly complement the traditional ground-based methods, which is only for one site. Our study, to our current knowledge, is the first intercomparison study of PBLH on a large scale using long-term radiosonde observations in China. Three matchup schemes were proposed based on the position of radiosondes relative to CALIPSO ground tracks in China. Results indicate that CALIOP is promising for reliable PBLH retrievals.
Remotely sensed data could provide continuous spatial coverage of aerosol property over the pan-Eurasian area for PEEX program. The AATSR data can be used to retrieve aerosol optical depth (AOD). The Aerosol_cci project provides users with three AOD retrieval algorithms for AATSR data. Because China is vast in territory and has great differences in terms of land surfaces, the combination of the AERONET and CARSNET data can validate the Level 2 AOD products from AATSR data more comprehensively.
Vegetation cover in the remote and cold areas of northern West Siberia is rapidly changing. Analysis of summer maximum vegetation productivity index collected over 15 years (2000–2014) by Terra/Aqua satellites revealed “greening” over the northern (tundra/tundra-forest) and widespread “browning” over the southern (taiga) parts of the region. The vegetation changes around 28 urbanized areas were different. Many Siberian cities become greener even against wider browning trends at the background.
Highly time- and chemically resolved submicron aerosol properties were characterized online for the first time during springtime in Nanjing by using the Aerodyne SP-AMS. Both chemical and size information of black carbon together with other aerosol species were simultaneously determined. An in-depth analysis of the data elucidates the sources and evolution processes of the fine aerosols in the YRD region. Our findings are valuable for air quality remediation in the densely populated regions.
We have a comprehensive characterization of the sources, variations and processes of submicron aerosols in Beijing in winter using HR-AMS and GC/MS measurements. The primary sources including traffic, cooking, biomass burning and coal combustion emissions, and secondary components were separated and quantified with PMF. Our results elucidated the important roles of primary emissions, particularly coal combustion, and aqueous-phase processing in the formation of severe air pollution in winter.
We study the potentially contrasting effects of enhanced ecosystem CO2 release in response to warmer temperatures vs. emissions of biogenic volatile organic compounds and their formation of secondary organic aerosol through a combination of measurements and modelling at a remote location in Eastern Siberia. The study aims to highlight the number of potentially opposing processes and complex interactions between vegetation physiology, soil processes and trace-gas exchanges in the climate system.
This manuscript introduces a conceptual design of a global, hierarchical observation network which provides tools and increased understanding to tackle the inter-connected environmental and societal challenges that we will face in the coming decades. Each ecosystem type on the globe has its own characteristic features that need to be taken into consideration. The hierarchical network is able to tackle problems related to large spatial scales, heterogeneity of ecosystems and their complexity.
M. Kulmala, H. K. Lappalainen, T. Petäjä, T. Kurten, V.-M. Kerminen, Y. Viisanen, P. Hari, S. Sorvari, J. Bäck, V. Bondur, N. Kasimov, V. Kotlyakov, G. Matvienko, A. Baklanov, H. D. Guo, A. Ding, H.-C. Hansson, and S. Zilitinkevich