Corrigendum: Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition.

This corrects the article DOI: 10.1038/sdata.2017.3.

Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition.

Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data. The observatories represent nine different environments, e.g., Arctic, Atlantic, Pacific and Mediterranean maritime, boreal forest, or high alpine atmospheric conditions. This is a unique collection of aerosol particle properties most relevant for studying aerosol-cloud interactions which constitute the largest uncertainty in anthropogenic radiative forcing of the climate. The dataset is appropriate for comprehensive aerosol characterization (e.g., closure studies of CCN), model-measurement intercomparison and satellite retrieval method evaluation, among others. Data have been acquired and processed following international recommendations for quality assurance and have undergone multiple stages of quality assessment.

Derivation of the density and refractive index of organic matter and elemental carbon from closure between physical and chemical aerosol properties.

Information on the density (rho) and refractive index m (=n-ik) of elemental carbon (ECa) and organic matter (OMa), the main carbon components of atmospheric aerosols, has frequently been obtained from closure calculations between physical and chemical aerosol properties. However, this approach has suffered from large uncertainties since there were more unknown (or poorly known) parameters than defining equations. In this study, we propose a method that avoids this ambiguity mainly by considering both optical and mass closure and by expressing the three ECa parameters (rho(ECa), n(ECa), k(ECa)) by a single (unknown) parameter. This allows mathematically rigorous determination of rho(Eca), m(ECa), rho(OMa) and m(OMa) from standard physico-chemical aerosol data and rigorous error analysis. The results are unambiguous and self-consistent, i.e., there is no difference between the chemically and physically derived p and m values of the atmospheric aerosol. Application of this method to our previously published data on biomass burning particles from Amazonia yields rho(ECa) = 1.8(+/-0.2) g/cm3, m(ECa) = 1.9(+/-0.1)-i0.20(-0.04/+0.02), rho(OMa) = 1.39(+/-0.13) g/cm3 and m(OMa) = 1.46(+/-0.02), where the launcertainty limits given in parenthesis are based on the principles of error propagation. The relatively low imaginary part of m(ECa) indicates the presence of only partially graphitized elemental carbon, which is consistentwith biomass burning aerosol dominated by smoldering combustion conditions.

Adipic and malonic acid aqueous solutions: surface tensions and saturation vapor pressures.

The surface tension of adipic aqueous solutions was measured as a function of temperature (T=278-313 K) and adipic acid mole fraction (X=0.000-0.003) using the Wilhelmy plate method. A parametrization fitted to these data is presented. The evaporation rates of binary water-malonic and water-adipic acid droplets were measured with a TDMA technique at different temperatures (T=293-300 K) and relative humidities (58-80%), and the saturation vapor pressures of subcooled liquid malonic and adipic acids were derived from the data using a binary evaporation model. The temperature dependence of the vapor pressures was obtained as least-squares fits to the derived vapor pressures: ln(Psat,l) (Pa)=220.2389-22634.96/T (K)-26.66767 ln T (K) for malonic acid and ln(Psat,l) (Pa)=140.6704-18230.97/T (K)-15.48011 ln T (K) for adipic acid.