scholarly journals Dust mass, cloud condensation nuclei, and ice-nucleating particle profiling with polarization lidar: updated POLIPHON conversion factors from global AERONET analysis

2019 ◽  
Vol 12 (9) ◽  
pp. 4849-4865 ◽  
Author(s):  
Albert Ansmann ◽  
Rodanthi-Elisavet Mamouri ◽  
Julian Hofer ◽  
Holger Baars ◽  
Dietrich Althausen ◽  
...  
Keyword(s):  
Surface Area ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Conversion Factors ◽  
Microphysical Properties ◽  
Central Asian ◽  
Volume Forms ◽  
Aerosol Type

Abstract. The POLIPHON (Polarization Lidar Photometer Networking) method permits the retrieval of particle number, surface area, and volume concentration for dust and non-dust aerosol components. The obtained microphysical properties are used to estimate height profiles of particle mass, cloud condensation nucleus (CCN) and ice-nucleating particle (INP) concentrations. The conversion of aerosol-type-dependent particle extinction coefficients, derived from polarization lidar observations, into the aerosol microphysical properties (number, surface area, volume) forms the central part of the POLIPHON computations. The conversion parameters are determined from Aerosol Robotic Network (AERONET) aerosol climatologies of optical and microphysical properties. In this article, we focus on the dust-related POLIPHON retrieval products and present an extended set of dust conversion factors considering all relevant deserts around the globe. We apply the new conversion factor set to a dust measurement with polarization lidar in Dushanbe, Tajikistan, in central Asia. Strong aerosol layering was observed with mineral dust advected from Kazakhstan (0–2 km height), Iran (2–5 km), the Arabian peninsula (5–7 km), and the Sahara (8–10 km). POLIPHON results obtained with different sets of conversion parameters were contrasted in this central Asian case study and permitted an estimation of the conversion uncertainties.

scholarly journals Dust mass, CCN, and INP profiling with polarization lidar: Updated POLIPHON conversion factors from global AERONET analysis

2019 ◽  
Author(s):  
Albert Ansmann ◽  
Rodanthi-Elisavet Mamouri ◽  
Julian Hofer ◽  
Holger Baars ◽  
Dietrich Althausen ◽  
...  
Keyword(s):  
Surface Area ◽  
Particle Number ◽  
Condensation Nucleus ◽  
Ice Nucleation ◽  
Cloud Condensation Nucleus ◽  
Conversion Factors ◽  
Microphysical Properties ◽  
Factor Set ◽  
Dust Measurement ◽  
Area And Volume

Abstract. The POLIPHON (Polarization Lidar Photometer Networking) method permits the retrieval of particle number, surface area, and volume concentration for dust and non-dust aerosol components. The obtained microphysical properties are used to estimate height profiles of particle mass, cloud condensation nucleus (CCN) and ice-nucleation particle (INP) concentrations. Of central importance is the conversion of the lidar-derived extinction profiles into aerosol miccrophysical properties (number, surface area, volume). These conversion parameters are determined from Aerosol Robotic Network (AERONET) aerosol climatologies of optical and microphysical properties. In this article we focus on the dust-related POLIPHON retrieval and present an updated set of dust conversion factors considering all relevant deserts around the globe. We apply the new conversion factor set to a dust measurement with polarization lidar in Dushanbe, Tajikistan, in central Asia. Strong aerosol layering was observed with mineral dust advected from Kazakhstan (0–2 km height), Iran (2–5 km), the Arabian peninsula (5–7 km), and the Sahara (8–10 km). POLIPHON results obtained with different sets of conversion parameters were contrasted and discussed in terms of uncertainties.

scholarly journals Tropospheric and stratospheric wildfire smoke profiling with lidar: Mass, surface area, CCN and INP retrieval

2020 ◽  
Author(s):  
Albert Ansmann ◽  
Kevin Ohneiser ◽  
Rodanthi-Elisavet Mamouri ◽  
Daniel A. Knopf ◽  
Igor Veselovskii ◽  
...  
Keyword(s):  
Surface Area ◽  
Large Scale ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Wildfire Smoke ◽  
Microphysical Properties ◽  
Southeastern Australia ◽  
Analysis Scheme ◽  
Air Chemistry ◽  
Ground Based Lidar

Abstract. We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, and surface area concentrations in the case of wildfire smoke layers as well as estimates of smoke-related cloud condensation nucleus (CCN) and ice-nucleating particle (INP) concentrations from single-wavelength backscatter lidar measurements at ground and in space. A central role in the data analysis play conversion factors to convert the measured optical into microphysical properties. The set of needed conversion parameters for wildfire smoke are derived from AERONET observations of major smoke events caused by record-breaking wildfires in western Canada in August 2017 and southeastern Australia in January–February 2020. The new smoke analysis scheme is applied to stratospheric CALIPSO observations of fresh smoke plumes over northern Canada in 2017 and New Zealand in January 2020 and to ground-based lidar observation in southern Chile in aged Australian smoke layers in January 2020. These case studies show the potential of spaceborne and ground-based lidars to document large-scale and long-lasting wildfire smoke events in large detail and thus to provide valuable information for climate-, cloud-, and air chemistry modeling efforts performed to investigate the role of wildfire smoke in the atmospheric system.

scholarly journals Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

2013 ◽  
Vol 13 (16) ◽  
pp. 7983-7996 ◽  
Author(s):  
Z. J. Wu ◽  
L. Poulain ◽  
S. Henning ◽  
K. Dieckmann ◽  
W. Birmili ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Sampling Period ◽  
Cloud Condensation Nucleus ◽  
Mountain Range ◽  
Mixing Rule ◽  
Hygroscopic Growth ◽  
Parameter Values ◽  
Ccn Activity

Abstract. Particle hygroscopic growth at 90% RH (relative humidity), cloud condensation nuclei (CCN) activity, and size-resolved chemical composition were concurrently measured in the Thüringer Wald mid-level mountain range in central Germany in the fall of 2010. The median hygroscopicity parameter values, κ, of 50, 75, 100, 150, 200, and 250 nm particles derived from hygroscopicity measurements are respectively 0.14, 0.14, 0.17, 0.21, 0.24, and 0.28 during the sampling period. The closure between HTDMA (Hygroscopicity Tandem Differential Mobility Analyzers)-measured (κHTDMA) and chemical composition-derived (κchem) hygroscopicity parameters was performed based on the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. Using size-averaged chemical composition, the κ values are substantially overpredicted (30 and 40% for 150 and 100 nm particles). Introducing size-resolved chemical composition substantially improved closure. We found that the evaporation of NH4NO3, which may happen in a HTDMA system, could lead to a discrepancy in predicted and measured particle hygroscopic growth. The hygroscopic parameter of the organic fraction, κorg, is positively correlated with the O : C ratio (κorg = 0.19 × (O : C) − 0.03). Such correlation is helpful to define the κorg value in the closure study. κ derived from CCN measurement was around 30% (varied with particle diameters) higher than that determined from particle hygroscopic growth measurements (here, hydrophilic mode is considered only). This difference might be explained by the surface tension effects, solution non-ideality, gas-particle partitioning of semivolatile compounds, and the partial solubility of constituents or non-dissolved particle matter. Therefore, extrapolating from HTDMA data to properties at the point of activation should be done with great care. Finally, closure study between CCNc (cloud condensation nucleus counter)-measured (κCCN) and chemical composition (κCCN, chem) was performed using CCNc-derived κ values for individual components. The results show that the κCCN can be well predicted using particle size-resolved chemical composition and the ZSR mixing rule.

scholarly journals No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

2012 ◽  
Vol 12 (6) ◽  
pp. 15373-15417 ◽  
Author(s):  
E. M. Dunne ◽  
L. A. Lee ◽  
C. L. Reddington ◽  
K. S. Carslaw
Keyword(s):  
Nucleation Rate ◽  
Atmospheric Aerosols ◽  
Large Scale ◽  
Cloud Condensation Nuclei ◽  
Cosmic Ray ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Significant Response ◽  
Short Term ◽  
Aerosol Properties

Abstract. Observed correlations between short-term decreases in cosmic ray ionisation and cloud and aerosol properties have been attributed to short-term decreases in the ion-induced nucleation rate. We use a global aerosol microphysics model to determine whether a 10-day reduction of 15% in the nucleation rate could generate a statistically significant response in aerosol concentrations and optical properties. As an upper limit to the possible effect of changes in the ion-induced nucleation rate, we perturb the total nucleation rate, which has been shown to generate particle concentrations and nucleation events in reasonable agreement with global observations. When measured against a known aerosol control state, the model predicts a 0.15% decrease in global mean cloud condensation nucleus concentrations at the surface. However, taking into account the variability in aerosol, no statistically significant response can be detected in concentrations of particles with diameters larger than 10 nm, in cloud condensation nuclei with diameters larger than 70 nm, or in the Ångström exponent. The results suggest that the observed correlation between short-term decreases in cosmic ray ionisation and cloud and aerosol properties cannot be explained by associated changes in the large-scale nucleation rate.

scholarly journals Tropospheric and stratospheric wildfire smoke profiling with lidar: mass, surface area, CCN, and INP retrieval

2021 ◽  
Vol 21 (12) ◽  
pp. 9779-9807
Author(s):  
Albert Ansmann ◽  
Kevin Ohneiser ◽  
Rodanthi-Elisavet Mamouri ◽  
Daniel A. Knopf ◽  
Igor Veselovskii ◽  
...  
Keyword(s):  
Surface Area ◽  
Large Scale ◽  
Cloud Condensation Nuclei ◽  
The United States ◽  
Optical Measurements ◽  
Wildfire Smoke ◽  
Microphysical Properties ◽  
Southeastern Australia ◽  
Analysis Scheme ◽  
Ground Based Lidar

Abstract. We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, surface area, and number concentrations in the case of wildfire smoke layers as well as estimates of smoke-related cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations from backscatter lidar measurements on the ground and in space. Conversion factors used to convert the optical measurements into microphysical properties play a central role in the data analysis, in addition to estimates of the smoke extinction-to-backscatter ratios required to obtain smoke extinction coefficients. The set of needed conversion parameters for wildfire smoke is derived from AERONET observations of major smoke events, e.g., in western Canada in August 2017, California in September 2020, and southeastern Australia in January–February 2020 as well as from AERONET long-term observations of smoke in the Amazon region, southern Africa, and Southeast Asia. The new smoke analysis scheme is applied to CALIPSO observations of tropospheric smoke plumes over the United States in September 2020 and to ground-based lidar observation in Punta Arenas, in southern Chile, in aged Australian smoke layers in the stratosphere in January 2020. These case studies show the potential of spaceborne and ground-based lidars to document large-scale and long-lasting wildfire smoke events in detail and thus to provide valuable information for climate, cloud, and air chemistry modeling efforts performed to investigate the role of wildfire smoke in the atmospheric system.

scholarly journals A single parameter representation of hygroscopic growth and cloud condensation nucleus activity

2007 ◽  
Vol 7 (8) ◽  
pp. 1961-1971 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis
Keyword(s):  
Compositional Data ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Atmospheric Particulate Matter ◽  
Cloud Condensation Nucleus ◽  
Hygroscopic Growth ◽  
Activation Data ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Ccn Activity

Abstract. We present a method to describe the relationship between particle dry diameter and cloud condensation nuclei (CCN) activity using a single hygroscopicity parameter κ. Values of the hygroscopicity parameter are between 0.5 and 1.4 for highly-CCN-active salts such as sodium chloride, between 0.01 and 0.5 for slightly to very hygroscopic organic species, and 0 for nonhygroscopic components. Observations indicate that atmospheric particulate matter is typically characterized by 0.1<κ<0.9. If compositional data are available and if the hygroscopicity parameter of each component is known, a multicomponent hygroscopicity parameter can be computed by weighting component hygroscopicity parameters by their volume fractions in the mixture. In the absence of information on chemical composition, experimental data for complex, multicomponent particles can be fitted to obtain the hygroscopicity parameter. The hygroscopicity parameter can thus also be used to conveniently model the CCN activity of atmospheric particles, including those containing insoluble components. We confirm the applicability of the hygroscopicity parameter and its mixing rule by applying it to published hygroscopic diameter growth factor and CCN-activation data for single- and multi-component particles containing varying amounts of inorganic, organic and surface active compounds. We suggest that κ may be fit to CCN data assuming σs/a=0.072 J m−2 and present a table of κ derived for this value and T=298.15 K. The predicted hygroscopicities for mixtures that contain the surfactant fulvic acid agree within uncertainties with the measured values. It thus appears that this approach is adequate for predicting CCN activity of mixed particles containing surface active materials, but the generality of this assumption requires further verification.

scholarly journals A single parameter representation of hygroscopic growth and cloud condensation nucleus activity – Part 3: Including surfactant partitioning

2012 ◽  
Vol 12 (9) ◽  
pp. 22687-22712 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis
Keyword(s):  
Cloud Condensation Nuclei ◽  
Cloud Droplet ◽  
Condensation Nucleus ◽  
Single Parameter ◽  
Cloud Condensation Nucleus ◽  
Extended Model ◽  
Hygroscopic Growth ◽  
Analytical Approximations ◽  
Critical Supersaturation ◽  
Kohler Theory

Abstract. Atmospheric particles can serve as cloud condensation nuclei in the atmosphere. The presence of surface active compounds in the particle may affect the critical supersaturation that is required to activate a particle. Modelling surfactants in the context of Köhler theory, however, is difficult because surfactant enrichment at the surface implies that a stable radial concentration gradient must exist in the droplet. In this study, we introduce a hybrid model that accounts for partitioning between the bulk and surface phases in the context of single parameter representations of cloud condensation nucleus activity. The presented formulation incorporates the analytical approximations introduced by Raatikainen and Laaksonen to yield a set of equations that maintain the conceptual and mathematical simplicity of the single parameter framework. The resulting set of equations allows users of the single parameter model to account for surfactant partitioning by applying minor modifications to already existing code. We apply this extended model to discuss several uncertainties that hinder our ability to precisely pinpoint the role of surface tension in cloud droplet activation with current measurement and data analysis approaches.

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