In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles
<p>Source functions for mechanically driven coarse-mode sea spray and dust aerosol particles span orders of magnitude owing to a combination of physical sensitivity in the system and large measurement uncertainty. Outside special idealized settings (such as wind tunnels), aerosol particle flux...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-12-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/15/7171/2022/amt-15-7171-2022.pdf |
| _version_ | 1811200795492745216 |
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| author | H. J. Park J. S. Reid L. S. Freire C. Jackson D. H. Richter |
| author_facet | H. J. Park J. S. Reid L. S. Freire C. Jackson D. H. Richter |
| author_sort | H. J. Park |
| collection | DOAJ |
| description | <p>Source functions for mechanically driven coarse-mode sea spray and dust aerosol particles span orders of magnitude owing to a combination of
physical sensitivity in the system and large measurement uncertainty. Outside special idealized settings (such as wind tunnels), aerosol particle
fluxes are largely inferred from a host of methods, including local eddy correlation, gradient methods, and dry deposition methods. In all of these
methods, it is difficult to relate point measurements from towers, ships, or aircraft to a general representative flux of aerosol particles. This
difficulty is from the particles' inhomogeneous distribution due to multiple spatiotemporal scales of an evolving marine environment. We
hypothesize that the current representation of a point in situ measurement of sea spray or dust particles is a likely contributor to the
unrealistic range of flux and concentration outcomes in the literature. This paper aims to help the interpretation of field data: we conduct a
series of high-resolution, cloud-free large eddy simulations (LESs) with Lagrangian particles to better understand the temporal evolution and
volumetric variability of coarse- to giant-mode marine aerosol particles and their relationship to turbulent transport. The study begins by
describing the Lagrangian LES model framework and simulates flux measurements that were made using numerical analogs to field practices such as the
eddy covariance method. Using these methods, turbulent flux sampling is quantified based on key features such as coherent structures within the
marine atmospheric boundary layer (MABL) and aerosol particle size. We show that for an unstable atmospheric stability, the MABL exhibits large
coherent eddy structures, and as a consequence, the flux measurement outcome becomes strongly tied to spatial length scales and relative sampling of
crosswise and streamwise sampling. For example, through the use of ogive curves, a given sampling duration of a fixed numerical sampling instrument is
found to capture 80 % of the aerosol flux given a sampling rate of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>z</mi><mi>f</mi><mo>/</mo><msub><mi>w</mi><mo>∗</mo></msub><mo>∼</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="42pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="495ebe3122088c076ea98d5bc4c1986c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-7171-2022-ie00001.svg" width="42pt" height="14pt" src="amt-15-7171-2022-ie00001.png"/></svg:svg></span></span> 0.2, whereas a spanwise moving instrument results in a
95 % capture. These coherent structures and other canonical features contribute to the lack of convergence to the true aerosol vertical flux at
any height. As expected, sampling all of the flow features results in a statistically robust flux signal. Analysis of a neutral boundary layer
configuration results in a lower predictive range due to weak or no vertical roll structures compared to the unstable boundary layer
setting. Finally, we take the results of each approach and compare their surface flux variability: a baseline metric used in regional and global
aerosol models.</p> |
| first_indexed | 2024-04-12T02:09:43Z |
| format | Article |
| id | doaj.art-0d07401a28f2470a9d106dbdb779e025 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-12T02:09:43Z |
| publishDate | 2022-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-0d07401a28f2470a9d106dbdb779e0252022-12-22T03:52:26ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482022-12-01157171719410.5194/amt-15-7171-2022In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particlesH. J. Park0J. S. Reid1L. S. Freire2C. Jackson3D. H. Richter4National Research Council Postdoctoral Fellow, US Naval Research Laboratory, Monterey, CA, USAMarine Meteorology Division, US Naval Research Laboratory, Monterey, CA, USAInstituto de Ciências Matemáticas e de Computação, University of São Paulo, São Carlos, BrazilConsultant, Global Science and Technology Inc., College Park, MD, USADepartment of Civil and Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, USA<p>Source functions for mechanically driven coarse-mode sea spray and dust aerosol particles span orders of magnitude owing to a combination of physical sensitivity in the system and large measurement uncertainty. Outside special idealized settings (such as wind tunnels), aerosol particle fluxes are largely inferred from a host of methods, including local eddy correlation, gradient methods, and dry deposition methods. In all of these methods, it is difficult to relate point measurements from towers, ships, or aircraft to a general representative flux of aerosol particles. This difficulty is from the particles' inhomogeneous distribution due to multiple spatiotemporal scales of an evolving marine environment. We hypothesize that the current representation of a point in situ measurement of sea spray or dust particles is a likely contributor to the unrealistic range of flux and concentration outcomes in the literature. This paper aims to help the interpretation of field data: we conduct a series of high-resolution, cloud-free large eddy simulations (LESs) with Lagrangian particles to better understand the temporal evolution and volumetric variability of coarse- to giant-mode marine aerosol particles and their relationship to turbulent transport. The study begins by describing the Lagrangian LES model framework and simulates flux measurements that were made using numerical analogs to field practices such as the eddy covariance method. Using these methods, turbulent flux sampling is quantified based on key features such as coherent structures within the marine atmospheric boundary layer (MABL) and aerosol particle size. We show that for an unstable atmospheric stability, the MABL exhibits large coherent eddy structures, and as a consequence, the flux measurement outcome becomes strongly tied to spatial length scales and relative sampling of crosswise and streamwise sampling. For example, through the use of ogive curves, a given sampling duration of a fixed numerical sampling instrument is found to capture 80 % of the aerosol flux given a sampling rate of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>z</mi><mi>f</mi><mo>/</mo><msub><mi>w</mi><mo>∗</mo></msub><mo>∼</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="42pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="495ebe3122088c076ea98d5bc4c1986c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-7171-2022-ie00001.svg" width="42pt" height="14pt" src="amt-15-7171-2022-ie00001.png"/></svg:svg></span></span> 0.2, whereas a spanwise moving instrument results in a 95 % capture. These coherent structures and other canonical features contribute to the lack of convergence to the true aerosol vertical flux at any height. As expected, sampling all of the flow features results in a statistically robust flux signal. Analysis of a neutral boundary layer configuration results in a lower predictive range due to weak or no vertical roll structures compared to the unstable boundary layer setting. Finally, we take the results of each approach and compare their surface flux variability: a baseline metric used in regional and global aerosol models.</p>https://amt.copernicus.org/articles/15/7171/2022/amt-15-7171-2022.pdf |
| spellingShingle | H. J. Park J. S. Reid L. S. Freire C. Jackson D. H. Richter In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles Atmospheric Measurement Techniques |
| title | In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles |
| title_full | In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles |
| title_fullStr | In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles |
| title_full_unstemmed | In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles |
| title_short | In situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with Lagrangian particles |
| title_sort | in situ particle sampling relationships to surface and turbulent fluxes using large eddy simulations with lagrangian particles |
| url | https://amt.copernicus.org/articles/15/7171/2022/amt-15-7171-2022.pdf |
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