A parameterization of sea-salt aerosol source function for sub- and super-micron particles

2003 ◽  
Vol 17 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
S. L. Gong
Keyword(s):  
Source Function ◽  
Sea Salt ◽  
Sea Salt Aerosol ◽  
Aerosol Source

scholarly journals Modelling of sea salt pollution over Europe: key uncertainties and comparison with observations

2011 ◽  
Vol 11 (4) ◽  
pp. 11143-11204
Author(s):  
S. Tsyro ◽  
W. Aas ◽  
J. Soares ◽  
M. Sofiev ◽  
H. Berge ◽  
...  
Keyword(s):  
Air Quality ◽  
Source Function ◽  
Temporal Correlation ◽  
Sea Salt ◽  
Sea Spray ◽  
Model Calculations ◽  
Sea Salt Aerosol ◽  
Calculation Results ◽  
Meteorological Input ◽  
Removal Processes

Abstract. Sea spray can significantly affect the air quality. Sea salt can cause enhanced concentrations of particulate matter and change particle chemical composition, in particular in coastal areas, and therefore should be accounted for in air quality modelling. We have used an EMEP Unified model to calculate sea salt concentrations and depositions over Europe, focusing on studying the effects of uncertainties in sea salt production and lifetime on calculation results. Model calculations of sea salt have been compared with EMEP observations of sodium concentrations in air and precipitation for a four year period, from 2004 to 2007, including size (fine/coarse) resolved EMEP intensive measurements in 2006 and 2007. In the presented calculations, sodium air concentrations are between 8 and 46% overestimated, whereas concentrations in precipitation are systematically underestimated by 65–70% for years 2004–2007. Unfortunately, thus far performed tests have failed to give a clear answer regarding the reason for this underestimation and further studies are needed. The model is found to reproduce fairly well the spatial distribution of Na+ in air and precipitation over Europe, and to capture most of sea salt episodes. The paper presents the main findings from a series of tests in which we compare several different sea spray source functions and also look at the effects of meteorological input and the efficiency of removal processes on calculated sea salt concentrations. Finally, sea salt calculations with the EMEP model have been compared with results from the SILAM model and observations for 2007. While the models produce fairly close results for Na+ at most of 26 measurement sites, discrepancies in terms of bias and temporal correlation are also found. Those differences are probably due to differences in the representation of source function and treatment of sea salt aerosol, and also due to different meteorology used for model runs and due to a finer grid resolution of the SILAM model compared to EMEP. This study contributes to getting a better insight on uncertainties associated with sea salt calculations with the EMEP model and towards further improvement of EMEP aerosol modelling.

scholarly journals Modeling sea-salt aerosol in a coupled climate and sectional microphysical model: mass, optical depth and number concentration

2010 ◽  
Vol 10 (10) ◽  
pp. 24499-24561 ◽  
Author(s):  
T. Fan ◽  
O. B. Toon
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Optical Depth ◽  
Source Function ◽  
Removal Rate ◽  
Global Climate Model ◽  
Number Concentration ◽  
Sea Salt ◽  
Aerosol Size Distribution ◽  
Sea Salt Aerosol

Abstract. Sea-salt aerosol mass, optical depth, and number concentration over the global oceans have significant implications for aerosol direct and indirect climate effects. We modeled sea-salt aerosol in a coupled climate and sectional microphysical model, CAM/CARMA, with aerosol dynamics including sea salt emission, gravitational sedimentation, dry deposition, wet scavenging, and particle swelling. We aimed at finding an integrated sea salt source function parameterization in the global climate model to simultaneously represent mass, optical depth, and number concentration. Each of these quantities is sensitive to a different part of the aerosol size distribution, which requires a size resolved microphysical model to treat properly. The CMS source function introduced in the research, based upon several earlier source functions, reproduced measurements of mass, optical depth and number concentration as well as the size distribution better than other source function choices we tried. However, as we note, it is also important to properly set the removal rate of the particles. The source function and removal rate are coupled in producing observed abundances. We find that sea-salt mass and optical depth peak in the winter, when winds are highest. However, surprisingly, particle numbers and CCN concentrations peak in summer when rainfall is lowest. The quadratic dependence of sea salt optical depth on wind speed, observed by some, is well represented in the model. We also found good agreement with the wind speed dependency of the number concentration at the measurement location and the regional scale. The work is the basis for further investigation of the effects of sea-salt aerosol on climate and atmospheric chemistry.

scholarly journals Modeling sea-salt aerosol in a coupled climate and sectional microphysical model: mass, optical depth and number concentration

2011 ◽  
Vol 11 (9) ◽  
pp. 4587-4610 ◽  
Author(s):  
T. Fan ◽  
O. B. Toon
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Optical Depth ◽  
Source Function ◽  
Removal Rate ◽  
Global Climate Model ◽  
Number Concentration ◽  
Sea Salt ◽  
Aerosol Size Distribution ◽  
Sea Salt Aerosol

Abstract. Sea-salt aerosol mass, optical depth, and number concentration over the global oceans have significant implications for aerosol direct and indirect climate effects. We model sea-salt aerosol in a coupled climate and sectional microphysical model, CAM/CARMA, with aerosol dynamics including sea-salt emission, gravitational sedimentation, dry deposition, wet scavenging, and hygroscopic growth. We aim to find an integrated sea-salt source function parameterization in the global climate model to simultaneously represent mass, optical depth, and number concentration. Each of these quantities is sensitive to a different part of the aerosol size distribution, which requires a size resolved microphysical model to treat properly. The CMS source function introduced in this research, based upon several earlier source functions, reproduces measurements of mass, optical depth and number concentration as well as the size distribution better than other source function choices we tried. However, as we note, it is also important to properly set the removal rate of the particles. The source function and removal rate are coupled in producing observed abundances. We find that sea salt mass and optical depth peak in the winter, when winds are highest. However, surprisingly, particle numbers and CCN concentrations peak in summer when rainfall is lowest. The quadratic dependence of sea-salt optical depth on wind speed, observed by some, is well represented in the model. We also find good agreement with the wind speed dependency of the number concentration at the measurement location and the regional scale. The work is the basis for further investigation of the effects of sea-salt aerosol on climate and atmospheric chemistry.

scholarly journals Modelling of sea salt concentrations over Europe: key uncertainties and comparison with observations

2011 ◽  
Vol 11 (20) ◽  
pp. 10367-10388 ◽  
Author(s):  
S. Tsyro ◽  
W. Aas ◽  
J. Soares ◽  
M. Sofiev ◽  
H. Berge ◽  
...  
Keyword(s):  
Air Quality ◽  
Source Function ◽  
Temporal Correlation ◽  
Sea Salt ◽  
Air Quality Modelling ◽  
Model Calculations ◽  
Sea Salt Aerosol ◽  
Calculation Results ◽  
Meteorological Input ◽  
Removal Processes

Abstract. Sea salt aerosol can significantly affect the air quality. Sea salt can cause enhanced concentrations of particulate matter and change particle chemical composition, in particular in coastal areas, and therefore should be accounted for in air quality modelling. We have used an EMEP Unified model to calculate sea salt concentrations and depositions over Europe, focusing on studying the effects of uncertainties in sea salt production and lifetime on calculation results. Model calculations of sea salt have been compared with EMEP observations of sodium concentrations in air and precipitation for a four year period, from 2004 to 2007, including size (fine/coarse) resolved EMEP intensive measurements in 2006 and 2007. In the presented calculations, sodium air concentrations are between 8% and 46% overestimated, whereas concentrations in precipitation are systematically underestimated by 65–70% for years 2004–2007. A series of model tests have been performed to investigate the reasons for this underestimation, but further studies are needed. The model is found to reproduce the spatial distribution of Na+ in air and precipitation over Europe fairly well, and to capture most of sea salt episodes. The paper presents the main findings from a series of tests in which we compare several different sea spray source functions and also look at the effects of meteorological input and the efficiency of removal processes on calculated sea salt concentrations. Finally, sea salt calculations with the EMEP model have been compared with results from the SILAM model and observations for 2007. While the models produce quite close results for Na+ at the majority of 26 measurement sites, discrepancies in terms of bias and temporal correlation are also found. Those differences are believed to occur due to differences in the representation of source function and size distribution of sea salt aerosol, different meteorology used for model runs and the different models' resolution. This study contributes to getting a better insight on uncertainties associated with sea salt calculations and thus facilitates further improvement of aerosol modelling on both regional and global scales.

scholarly journals On the evaluation of global sea-salt aerosol models at coastal/orographic sites

2015 ◽  
Vol 101 ◽  
pp. 41-48 ◽  
Author(s):  
M. Spada ◽  
O. Jorba ◽  
C. Pérez García-Pando ◽  
Z. Janjic ◽  
J.M. Baldasano
Keyword(s):  
Sea Salt ◽  
Sea Salt Aerosol

scholarly journals Solute in high arctic glacier snow cover and its impact on runoff chemistry

1998 ◽  
Vol 26 ◽  
pp. 156-160 ◽  
Author(s):  
Richard Hodgkins ◽  
Martyn Tranter
Keyword(s):  
Chemical Composition ◽  
Atmospheric Transport ◽  
Total Concentration ◽  
High Arctic ◽  
Sea Salt ◽  
Acidic Ph ◽  
Sea Salt Aerosol ◽  
Wet Snow ◽  
Potential Contributor ◽  
Arctic Glacier

The chemical composition of snow and meltwater in the 13 km2 catchment of Scott Turnerbreen, Svalbard, was investigated during the spring and summer of 1993. This paper assesses the provenance of solute in the snowpack and its impact on runoff chemistry. Dry snow contains 420μeql-1 of solute, is slightly acidic (pH 5.4) and is dominated by Na+ and Cl-. Wet snow is more dilute (total concentration 340μeql-1), and less acidic (pH 5.9). This is consistent with the elution of ions from the snowpack by meltwater. Snowpack solute can be partitioned into the following fractions: sea-salt aerosol, acid aerosol and crustal. About 98% of snowpack solute is sea salt, yielding 22000 kg km-2a-1. The behaviour of snowpack-derived Cl- in runoff is distinctive, peaking at over 800 μeql-1 early in the melt season as runoff picks up, before declining quasi-exponentially. This represents the discharge of snowmelt concentrated by elution within the snowpack which subsequently becomes relatively dilute. A solute yield of 140 kg km-2 a-1 can be attributed to anthropogenically generated acid aerosols, representing long-range atmospheric transport of pollutants, a potential contributor to Arctic runoff acidification.

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