On the cloud processing of aerosol particles: An entraining air-parcel model with two-dimensional spectral cloud microphysics and a new formulation of the collection kernel

2003 ◽  
Vol 129 (587) ◽  
pp. 1-18 ◽  
Author(s):  
Astrid Kerkweg ◽  
Sabine Wurzler ◽  
Tamir Reisin ◽  
Andreas Bott
Keyword(s):  
Aerosol Particles ◽  
Cloud Microphysics ◽  
Two Dimensional ◽  
Cloud Processing ◽  
New Formulation

scholarly journals Cloud Processing of Aerosol Particles in Marine Stratocumulus Clouds

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 520 ◽  
Author(s):  
Andrea I. Flossmann ◽  
Wolfram Wobrock
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Numerical Study ◽  
Spatial Scales ◽  
Aerosol Particles ◽  
Cloud Microphysics ◽  
Marine Stratocumulus ◽  
Boundary Layer Clouds ◽  
Cloud Processing ◽  
Stratocumulus Clouds

Cloud processing of aerosol particles is an important process and is, for example, thought to be responsible for the so-called “Hoppel-minimum” in the marine aerosol particle distribution or contribute to the cell organization of marine boundary layer clouds. A numerical study of the temporal and spatial scales of the processing of aerosol particles by typical marine stratocumulus clouds is presented. The dynamical framework is inspired by observations during the VOCALS (Variability of the American Monsoon System Ocean-Cloud-Atmosphere-Land Study) Regional Experiment in the Southeast Pacific. The 3-D mesoscale model version of DESCAM (Detailed Scavenging Model) follows cloud microphysics of the stratocumulus deck in a bin-resolved manner and has been extended to keep track of cloud-processed particles in addition to non-processed aerosol particles in the air and inside the cloud drops. The simulation follows the evolution of the processing of aerosol particles by the cloud. It is found that within one hour almost all boundary layer aerosol particles have passed through at least one cloud cycle. However, as the in-cloud residence times of the particles in the considered case are only on the order of minutes, the aerosol particles remain essentially unchanged. Our findings suggest that in order to produce noticeable microphysical and dynamical effects in the marine boundary layer clouds, cloud processing needs to continue for extended periods of time, exceeding largely the time period considered in the present study. A second model study is dedicated to the interaction of ship track particles with marine boundary layer clouds. The model simulates quite satisfactorily the incorporation of the ship plume particles into the cloud. The observed time and spatial scales and a possible Twomey effect were reproduced.

On Extension of “Heatline” and “Massline” Concepts to Reacting Flows Through Use of Conserved Scalars

2002 ◽  
Vol 124 (4) ◽  
pp. 791-799 ◽  
Author(s):  
Achintya Mukhopadhyay ◽  
Xiao Qin ◽  
Suresh K. Aggarwal ◽  
Ishwar K. Puri
Keyword(s):  
Diffusion Coefficients ◽  
Reacting Flows ◽  
Scalar Transport ◽  
Zero Gravity ◽  
Two Dimensional ◽  
Total Enthalpy ◽  
Mass Fractions ◽  
New Formulation ◽  
Elemental Mass ◽  
Qualitative Picture

A new formulation for extending the concept of heatlines and masslines to reacting flows through use of conserved scalars has been proposed. The formulation takes into account the distinct diffusion coefficients of different species. Results have been obtained for a number of two-dimensional nonreacting and reacting free shear flows under normal and zero gravity. For nonreacting flows, total enthalpy and elemental mass fractions have been used as the transported conserved scalars. For reacting flows, mixture fractions, defined as normalized elemental mass fractions and enthalpy, have been employed. The results show this concept to be a useful tool for obtaining better insights into the global qualitative picture of scalar transport for both nonreacting and reacting flows.

scholarly journals MADE-IN: a new aerosol microphysics submodel for global simulation of potential atmospheric ice nuclei

2010 ◽  
Vol 3 (4) ◽  
pp. 2221-2290 ◽  
Author(s):  
V. Aquila ◽  
J. Hendricks ◽  
A. Lauer ◽  
N. Riemer ◽  
H. Vogel ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Aerosol Particles ◽  
Ice Crystals ◽  
Dust Particles ◽  
Airborne Measurements ◽  
Cloud Processing ◽  
Ice Nuclei ◽  
Hygroscopic Properties ◽  
Mixing States ◽  
Made In

Abstract. Black carbon (BC) and mineral dust are among the dominant atmospheric ice nuclei, i.e. aerosol particles that can initiate heterogeneous nucleation of ice crystals. When released, most BC and dust particles are externally mixed with other aerosol compounds. Through coagulation with particles containing soluble material and condensation of gases, externally mixed particles may obtain a coating and be transferred into an internal mixture. The mixing state of BC and dust aerosol particles influences their radiative and hygroscopic properties, as well as their ability of building ice crystals. We introduce the new aerosol microphysics submodel MADE-IN, implemented within the ECHAM/MESSy Atmospheric Chemistry global model (EMAC). MADE-IN is able to track separately mass and number concentrations of BC and dust particles in their different mixing states, as well as particles free of BC and dust. MADE-IN describes these three classes of particles through a superposition of seven log-normally distributed modes, and predicts the evolution of their size distribution and chemical composition. Six out of the seven modes are mutually interacting, allowing for the transfer of mass and number among them. Separate modes for the different mixing states of BC and dust particles in EMAC/MADE-IN allow for explicit simulations of the relevant aging processes, i.e. condensation, coagulation and cloud processing. EMAC/MADE-IN has been evaluated with surface and airborne measurements and performs well both in the planetary boundary layer and in the upper troposphere and lowermost stratosphere. Such a model represents a highly appropriate tool for the study of the concentration and composition of potential atmospheric ice nuclei.

scholarly journals Aerosol properties, source identification, and cloud processing in orographic clouds measured by single particle mass spectrometry on a Central European mountain site during HCCT-2010

2015 ◽  
Vol 15 (17) ◽  
pp. 24419-24472 ◽  
Author(s):  
A. Roth ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Mertes ◽  
D. van Pinxteren ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Single Particle ◽  
Mass Spectra ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Algorithm Analysis ◽  
Sorting Algorithm ◽  
Condensation Nuclei ◽  
Cloud Processing ◽  
Orographic Clouds

Abstract. Cloud residues and out-of-cloud aerosol particles with diameters between 150 and 900 nm have been analysed by on-line single particle aerosol mass spectrometry during the six-week study HCCT-2010 in September/October 2010. The measurement location was the mountain Schmücke (937 m a.s.l.) in Central Germany. More than 170 000 bipolar mass spectra from out-of-cloud aerosol particles and more than 14 000 bipolar mass spectra from cloud residual particles were obtained and were classified using a fuzzy c-means clustering algorithm. Analysis of the uncertainty of the sorting algorithm was conducted on a subset of the data by comparing the clustering output with particle-by-particle inspection and classification by the operator. This analysis yielded a false classification probability between 13 and 48 %. Additionally, particle types were identified by specific marker ions. The results from the ambient aerosol analysis show that 63 % of the analysed particles belong to clusters indicating a diurnal variation, suggesting that local or regional sources dominate the aerosol, especially for particles containing soot and biomass burning particles. In the cloud residues the relative percentage of large soot-containing particles and particles containing amines was found to be increased compared to the out-of-cloud aerosol, while in general organic particles were less abundant in the cloud residues. In the case of amines this can be explained by the high solubility of the amines, while the large soot-containing particles were found to be internally mixed with inorganics, which explains their activation as cloud condensation nuclei. Furthermore, the results show that during cloud processing, both sulphate and nitrate are added to the residual particles, thereby changing the mixing state and increasing the fraction of particles with nitrate and/or sulphate. This is expected to lead to higher hygroscopicity after cloud evaporation, and therefore to an increase of the particles' ability to act as cloud condensation nuclei after their cloud passage.

scholarly journals Cloud processing of continental aerosol particles: Experimental investigations for different drop sizes

2000 ◽  
Vol 105 (D9) ◽  
pp. 11739-11752 ◽  
Author(s):  
Martina Krämer ◽  
Norbert Beltz ◽  
Dieter Schell ◽  
Lothar Schütz ◽  
Cornelia Sprengard-Eichel ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Experimental Investigations ◽  
Cloud Processing
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