SALSA – a Sectional Aerosol module for Large Scale   Applications

Kokkola, Harri; Korhonen, Hannele; Lehtinen, K. E. J.; Makkonen, Risto; Asmi, Ari; Järvenoja, Simo; Anttila, T.; Partanen, Antti‐Ilari; Kulmala, Markku; Järvinen, Heikki; Laaksonen, A.; Kerminen, V.-M.

doi:10.5194/acp-8-2469-2008

Cited by 127 publications

(133 citation statements)

References 70 publications

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“…To reduce the amount of tracer variables, for the three largest size sections in SALSA only the number concentration and the fixed mean radius of the size section are stored, so condensation and coagulation can not increase the size of these particles. Only the growth of particles from smaller subregions affects the number concentration and the largest size classes (see Kokkola et al, 2008). In Fig.…”

Section: High So 2 Concentrationmentioning

confidence: 99%

“…For a more detailed description of the treatment of aerosol compounds, methods for microphysical processes, and the division of size sections in SALSA, see Kokkola et al (2008).…”

Section: Salsamentioning

confidence: 99%

“…be simplified. The aerosol distribution in aerosol modules is described in most cases using the bulk approach (Liao and Seinfeld, 2005;Liu et al, 2005;Reddy et al, 2005;, modal approach (Ghan et al, 2001;Wilson et al, 2001;Herzog et al, 2004;Vignati et al, 2004;Lauer et al, 2005;Stier et al, 2005), and sectional approach (Weisenstein et al, 1997;Jacobson, 2001;Timmreck, 2001;Rodriguez and Dabdub, 2004;Spracklen et al, 2005;Hommel, 2008;Kokkola et al, 2008). In the bulk approach, only the aerosol mass is prognostic.…”

Section: Introductionmentioning

confidence: 99%

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Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

et al. 2009

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Abstract. In this manuscript, we present an intercomparison of three different aerosol microphysics modules that are implemented in the climate model ECHAM5. The comparison was done between the modal aerosol microphysics module M7, which is currently the default aerosol microphysical core in ECHAM5, and two sectional aerosol microphysics modules SALSA, and SAM2. The detailed aerosol microphysical model MAIA was used as a reference to evaluate the results of the aerosol microphysics modules with respect to sulphate aerosol.The ability of the modules to describe the development of the aerosol size distribution was tested in a zero dimensional framework. We evaluated the strengths and weaknesses of different approaches under different types of stratospheric conditions. Also, we present an improved method for the time integration in M7 and study how the setup of the modal aerosol modules affects the evolution of the aerosol size distribution.Intercomparison simulations were carried out with varying SO 2 concentrations from background conditions to extreme values arising from stratospheric injections by large volcanic eruptions. Under background conditions, all microphysics modules were in good agreement describing the shape of the aerosol size distribution, but the scatter between the model results increased with increasing SO 2 concentrations. In particular in the volcanic case the setups of the aerosol modules have to be adapted in order to dependably capture the evoluCorrespondence to: H. Kokkola (harri.kokkola@fmi.fi) tion of the aerosol size distribution, and to perform in global model simulations.In summary, this intercomparison serves as a review of the different aerosol microphysics modules which are currently available for the climate model ECHAM5.

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Section: High So 2 Concentrationmentioning

confidence: 99%

“…For a more detailed description of the treatment of aerosol compounds, methods for microphysical processes, and the division of size sections in SALSA, see Kokkola et al (2008).…”

Section: Salsamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

et al. 2009

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“…In the most sophisticated parameterizations, CDNC is calculated based on aerosol particle size distribution and chemical composition, pressure, temperature and vertical velocity of air parcel forming the cloud (Abdul-Razzak et al, 1998;Ghan, 2000, 2002;Nenes and Seinfeld, 2003;Fountoukis and Nenes, 2005). The simulations in this study are conducted using the SALSA sectional aerosol model developed for atmospheric models (Kokkola et al, 2008;Bergman et al, 2012). In SALSA, aerosol size distribution is divided to different subranges based on the particle size (3-50, 50-700, and 700-10 000 nm).…”

Section: Cloud Droplet Formation Parameterizationmentioning

confidence: 99%

“…In sectional models, the continuous aerosol particle size distributions are represented with discrete size sections (e.g. Weisenstein et al, 2007;Jacobson, 2001;Rodriguez and Dabdub, 2004;Kokkola et al, 2008). The accuracy of the description of the size distribution increases with increasing number of size sections.…”

Section: Introductionmentioning

confidence: 99%

Correction of approximation errors with Random Forests applied to modelling of cloud droplet formation

et al. 2013

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Abstract. In atmospheric models, due to their computational time or resource limitations, physical processes have to be simulated using reduced (i.e. simplified) models. The use of a reduced model, however, induces errors to the simulation results. These errors are referred to as approximation errors. In this paper, we propose a novel approach to correct these approximation errors. We model the approximation error as an additive noise process in the simulation model and employ the Random Forest (RF) regression algorithm for constructing a computationally low cost predictor for the approximation error. In this way, the overall simulation problem is decomposed into two separate and computationally efficient simulation problems: solution of the reduced model and prediction of the approximation error realisation. The approach is tested for handling approximation errors due to a reduced coarse sectional representation of aerosol size distribution in a cloud droplet formation calculation as well as for compensating the uncertainty caused by the aerosol activation parameterization itself. The results show a significant improvement in the accuracy of the simulation compared to the conventional simulation with a reduced model. The proposed approach is rather general and extension of it to different parameterizations or reduced process models that are coupled to geoscientific models is a straightforward task. Another major benefit of this method is that it can be applied to physical processes that are dependent on a large number of variables making them difficult to be parameterized by traditional methods.

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Geographical and diurnal features of amine‐enhanced boundary layer nucleation

et al. 2015

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Amines have recently been found to be an important ingredient in the nucleation and initial growth of atmospheric aerosols; however, global estimates of the spatial and temporal extent of amine‐enhanced nucleation are currently missing. We utilize two recently published laboratory data sets of amine‐sulfuric acid nucleation to evaluate the accuracy of previously published nucleation parameterizations and to produce a new amine‐enhanced new particle formation (NPF) parameterization that better reproduces the laboratory observations at atmospherically relevant sulfuric acid concentrations. We implement and compare the amine‐enhanced NPF parameterizations and a kinetic nucleation parameterization within the global aerosol‐climate model ECHAM‐HAMMOZ and find that the spatial features of amine‐enhanced and kinetic NPF are clearly different. Amine‐enhanced NPF is limited to areas near the source regions of amine due to its short gas phase residence time of 6.9 h, whereas kinetic nucleation (which depends only on sulfuric acid concentration) produces particles more uniformly across the globe due to long‐range transport of SO2. The notably stronger land‐sea contrast in amine‐enhanced nucleation simulations is in line with relatively rare atmospheric observations of NPF over open oceans. However, when the uptake of gas phase amine molecules to aerosol particles is limited according to previously published estimates (0.2% of collisions leading to uptake), the amine‐enhanced NPF parameterization predicts in some regions unrealistically high NPF rates (∼1000 cm−3 s−1) compared to typical observations. Our results indicate that amine‐enhanced nucleation may be an important particle formation mechanism near amine source regions but also highlights the need for more tightly defined constraints on the spatial and temporal distribution of amine emissions, gas‐to‐particle partitioning mechanisms of amines, and condensation and coagulation sinks in global models.

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SALSA – a Sectional Aerosol module for Large Scale Applications

Cited by 127 publications

References 70 publications

Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

Correction of approximation errors with Random Forests applied to modelling of cloud droplet formation

Geographical and diurnal features of amine‐enhanced boundary layer nucleation

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