A5043324697- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- nanoparticles nucleation surface interactions
- Air Quality and Health Impacts
- Advanced Thermodynamics and Statistical Mechanics
- Crystallization and Solubility Studies
- Radioactivity and Radon Measurements
- Advanced Chemical Physics Studies
- Radioactive contamination and transfer
- Geological Studies and Exploration
- Spectroscopy and Quantum Chemical Studies
- Phase Equilibria and Thermodynamics
- Methane Hydrates and Related Phenomena
- Arctic and Antarctic ice dynamics
- Cryospheric studies and observations
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Meteorological Phenomena and Simulations
- Climate change and permafrost
- Plant responses to elevated CO2
- Chemical Thermodynamics and Molecular Structure
- Aeolian processes and effects
- Chemical and Physical Properties in Aqueous Solutions
Finnish Meteorological Institute
2011-2024
University of Helsinki
2005-2014
Swedish Meteorological and Hydrological Institute
2002
Quality Research
2002
Max Planck Institute for Biophysical Chemistry
1993-1996
University of Vienna
1991
Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up half global cloud condensation nuclei. Aerosols can cause a net cooling climate by scattering sunlight and leading smaller but more numerous droplets, which makes clouds brighter extends their lifetimes. Atmospheric aerosols derived human activities are have compensated for large fraction the warming caused greenhouse gases. However, despite its importance climate, nucleation poorly understood. Recently,...
Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity variability atmosphere has hindered elucidation fundamental mechanism from gaseous precursors. We show, in experiments performed with CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid oxidized organic vapors concentrations reproduce particle nucleation rates observed lower atmosphere. reveal a involving clusters containing molecules...
Aerosols play a key role in the radiation balance of atmosphere. Here, we present evidence that European boreal region is substantial source both aerosol mass and number. The investigation supplies straightforward relation between emissions monoterpenes gas-to-particle formation over regions substantially lacking anthropogenic sources. Our results show forest provides an population 1000 to 2000 particles climatically active sizes per cubic centimeter during late spring early fall period....
Abstract. A global vertically resolved aerosol data set covering more than 10 years of observations at 20 measurement sites distributed from 63° N to 52° S and 72° W 124° E has been achieved within the Raman polarization lidar network PollyNET. This consists portable, remote-controlled multiwavelength-polarization-Raman lidars (Polly) for automated continuous 24/7 clouds aerosols. PollyNET is an independent, voluntary, scientific network. All Polly feature a standardized instrument design...
Classical theory of binary homogeneous nucleation is extended to the ternary system H 2 SO 4 ‐NH 3 ‐H O. For NH mixing ratios exceeding about 1 ppt, presence enhances O rate by several orders magnitude. The Gibbs free energies formation critical cluster, as calculated two independent approaches, are in substantial agreement. finding that relative humidity over a large range concentrations has wide atmospheric consequences. limiting component for is, case, ; however, concentration needed...
Aerosol formation and subsequent particle growth in ambient air have been frequently observed at a boreal forest site (SMEAR II station) Southern Finland. The EU funded project BIOFOR (Biogenic aerosol the forest) has focused on: (a) determination of mechanisms particles site; (b) verification emissions secondary organic aerosols from (c) quantification amount condensable vapours produced photochemical reactions biogenic volatile compounds (BVOC) leading to formation. approach was combine...
We have investigated homogeneous nucleation of water droplets in the vapor phase. Nucleation has been previously studied a number times using various experimental techniques. The pulse technique used here allows accurate measurements rates J vs supersaturation S range from 105 to 109 cm−3 s−1. advance reported consists fact that J–S curves are measured at selectable constant temperature. determined supersaturated mixed with carrier gases as functions and temperature...
In order to predict the current state and future development of Earth's climate system, detailed knowledge on how atmospheric aerosol particles from various sources interact with clouds is needed. this article we present, based continuous measurements in a remote continental location, direct observational evidence that formed atmosphere gaseous precursors eventually participate into cloud droplet activation. By combining measurement data theoretical calculations, further demonstrate albedo...
A dedicated study into the formation of new particles, New Particle Formation and Fate in Coastal Environment (PARFORCE), was conducted over a period from 1998 to 1999 at Mace Head Atmospheric Research Station on western coast Ireland. Continuous measurements particle were taken 2‐year while two intensive field campaigns also conducted, one September other June 1999. events observed ∼90% days occurred throughout year all air mass types. These lasted for, typically, few hours, with some...
Abstract. Aerosol physical and chemical properties trace gas concentrations were measured during the QUEST field campaign in March–April 2003, Hyytiälä, Finland. Our aim was to understand role of oxidation products VOC's such as mono- sesquiterpenes atmospheric nucleation events. Particle compositions using Aerodyne Mass Spectrometer, aerosol samples collected with low-pressure impactors a high volume sampler analysed number techniques. The results indicate that after new particle formation,...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Problem of Measuring Homogeneous Nucleation Rates and the Molecular Contents Nuclei: Progress in Form Pulse MeasurementsR. Strey, P. E. Wagner, Y. ViisanenCite this: J. Phys. Chem. 1994, 98, 32, 7748–7758Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published inissue 1 August 1994https://pubs.acs.org/doi/10.1021/j100083a003https://doi.org/10.1021/j100083a003research-articleACS PublicationsRequest reuse...
Abstract. Many of the next generation global climate models will include aerosol schemes which explicitly simulate microphysical processes that determine particle size distribution. These enable optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental processes, should lead a more physically based simulation direct indirect radiative forcings. This study examines variation in distribution simulated 12 microphysics quantify model diversity identify...
We analyzed aerosol size distributions from the Finnish measuring stations at Hyytiälä, Värriö and Pallas Swedish station Aspvreten over a period of several years. identified occurrences new particle formation bursts obtained characteristics for distribution data. In addition, we directions which air masses leading to arrived. found that occurs whole area covered by measurement stations. The Northern Atlantic is dominating as source all occurrence had similar annual variation stations, with...
Abstract. Secondary new particle formation affects atmospheric aerosol and cloud droplet numbers thereby, the effects on climate. In this paper, frequency of nucleation events associated growth rates, along with their seasonal variation, was analysed based over ten years measurements conducted at Pallas GAW station in northern Finland. The long-term also allowed a detailed examination factors possibly favouring or suppressing formation. Effects meteorological parameters air mass properties...
Abstract. Four years of continuous aerosol number size distribution measurements from the Arctic Climate Observatory in Tiksi, Russia, are analyzed. Tiksi is located a region where situ information on particle properties has not been previously available. Particle distributions were measured with differential mobility sizer (in diameter range 7–500 nm) and an aerodynamic 0.5–10 μm). Source effects modal features number, mass concentrations presented for different seasons. The monthly median...
Abstract. The formation of particles from precursor vapors is an important source atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility CERN tries to elucidate which are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns CLOUD stainless-steel aerosol chamber focused on investigating particle ammonia (NH3) sulfuric acid (H2SO4). Experiments were conducted presence water, ozone sulfur dioxide. Contaminant...
Abstract International Arctic Systems for Observing the Atmosphere (IASOA) activities and partnerships were initiated as a part of 2007–09 Polar Year (IPY) are expected to continue many decades legacy program. The IASOA focus is on coordinating intensive measurements atmosphere collected in United States, Canada, Russia, Norway, Finland, Greenland create synthesis science that leads an understanding why not just how evolving. premise there limitations with modeling satellite observations can...
Abstract. Subsea permafrost and hydrates in the East Siberian Arctic Shelf (ESAS) constitute a substantial carbon pool, potentially large source of methane to atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8–17 TgCH4 yr−1. Here, we propose insights observations evaluate these estimates. The comparison high-resolution simulations mole fractions continuous during whole year 2012 confirms high variability...
Abstract. Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal geographical differences of size properties. The involved cover large area ranging from the Finnish Lapland (67º N) down to southern Sweden (56º in order Värriö, Pallas, Hyytiälä, Aspvreten Vavihill. shape is typically bimodal winter larger fraction accumulation mode particles compared other seasons....
Two years of continuous aerosol particle size distribution measurements provided the basis for this cloud droplet activation study. The particles was studied in Pallas, a clean background site northern Finland. A slightly different approach compared with traditional methods is presented by measuring simultaneously interstitial spectrum and nearby out‐of‐cloud spectrum. main advantage that one can determine activated fraction different‐size over whole submicron‐size range large number events...
During a 33‐month measurement period at high‐latitude background site in northern Finland, total of 103 new particle formation events were observed. In 19 cases, movement the air masses allowed observation and growth over sufficiently long time to investigate production “potential” cloud condensation nuclei (CCN) resulting from new‐particle formation. All CCN took place relatively clean that had traversed Northern Atlantic/Arctic Ocean prior arrival our site. The number formed new, varied...
We present measurements of binary homogeneous nucleation sulfuric acid and water vapors at 298 K two different relative humidities (38.2% 52.3%), H2SO4 vapor concentrations ranging from about 1⋅1010 to 3⋅1010 molecules/cc. The experimental setup consisted a turbulent mixing unit combined with flow chamber where the took place. Particular attention was paid generation vapor. measured rates vary between 2 3000 cm−3 s−1. results are compared other found in literature. Our agreement predictions...
Particulate pollution of mainly anthropogenic origin is a widely spread phenomenon in southern Asia, influencing climate and causing adverse health effects on humans. In this paper, we analyze continuous measurements aerosol scattering absorption properties that were conducted Mukteshwar, remote site the Himalayan Mountains northern India, during September 2005–September 2007. While concentrations somewhat lower than those measured closer to urban areas some optical parameters had noticeable...