Convective distribution of dust over the Arabian Peninsula: the impact of model resolution
<p>Along the coasts of the Arabian Peninsula, convective dust storms are a considerable source of mineral dust to the atmosphere. Reliable predictions of convective dust events are necessary to determine their effects on air quality, visibility, and the radiation budget. In this study, the Wea...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/2967/2020/acp-20-2967-2020.pdf |
| _version_ | 1818487404115263488 |
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| author | J. Bukowski S. C. van den Heever |
| author_facet | J. Bukowski S. C. van den Heever |
| author_sort | J. Bukowski |
| collection | DOAJ |
| description | <p>Along the coasts of the Arabian Peninsula, convective dust storms are a
considerable source of mineral dust to the atmosphere. Reliable predictions
of convective dust events are necessary to determine their effects on air
quality, visibility, and the radiation budget. In this study, the Weather
Research and Forecasting Model coupled with Chemistry (WRF-Chem) is used to
simulate a 2016 summertime dust event over the Arabian Peninsula and examine
the variability in dust fields and associated vertical transport due to the
choice of convective parameterization and convection-permitting versus
parameterized convection. Simulations are run at 45 and 15 km grid
spacing with multiple cumulus parameterizations, and are compared to a 3 km
simulation that permits explicit dry and moist convective processes. Five
separate cumulus parameterizations at 15 km grid spacing were tested to
quantify the spread across different parameterizations. Finally, the impact
these variations have on radiation, specifically aerosol heating rates is
also investigated.</p>
<p>On average, in these simulations the convection-permitting case produces
higher quantities of dust than the parameterized cases in terms of dust
uplift potential, vertical dust concentrations, and vertical dust fluxes.
Major drivers of this discrepancy between the simulations stem from the
convection-permitting case exhibiting higher surface wind speeds during
convective activity; lower dust emission wind threshold velocities due to
drier soil; and more frequent, stronger vertical velocities which transport
dust aloft and increase the atmospheric lifetime of these particles. For
aerosol heating rates in the lowest levels, the shortwave effect prevails in
the convection-permitting case with a net cooling effect, whereas a longwave
net warming effect is present in the parameterized cases. The spread in dust
concentrations across cumulus parameterizations at the same grid resolution
(15 km) is an order of magnitude lower than the impact of moving from
parameterized towards explicit convection. We conclude that tuning dust
emissions in coarse-resolution simulations can only improve the results to
first-order and cannot fully rectify the discrepancies originating from
disparities in the representation of convective dust transport.</p> |
| first_indexed | 2024-12-10T16:37:21Z |
| format | Article |
| id | doaj.art-a5bffbb5a87f4ccc9235f29dcdf32ede |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-10T16:37:21Z |
| publishDate | 2020-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a5bffbb5a87f4ccc9235f29dcdf32ede2022-12-22T01:41:21ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-03-01202967298610.5194/acp-20-2967-2020Convective distribution of dust over the Arabian Peninsula: the impact of model resolutionJ. BukowskiS. C. van den Heever<p>Along the coasts of the Arabian Peninsula, convective dust storms are a considerable source of mineral dust to the atmosphere. Reliable predictions of convective dust events are necessary to determine their effects on air quality, visibility, and the radiation budget. In this study, the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) is used to simulate a 2016 summertime dust event over the Arabian Peninsula and examine the variability in dust fields and associated vertical transport due to the choice of convective parameterization and convection-permitting versus parameterized convection. Simulations are run at 45 and 15 km grid spacing with multiple cumulus parameterizations, and are compared to a 3 km simulation that permits explicit dry and moist convective processes. Five separate cumulus parameterizations at 15 km grid spacing were tested to quantify the spread across different parameterizations. Finally, the impact these variations have on radiation, specifically aerosol heating rates is also investigated.</p> <p>On average, in these simulations the convection-permitting case produces higher quantities of dust than the parameterized cases in terms of dust uplift potential, vertical dust concentrations, and vertical dust fluxes. Major drivers of this discrepancy between the simulations stem from the convection-permitting case exhibiting higher surface wind speeds during convective activity; lower dust emission wind threshold velocities due to drier soil; and more frequent, stronger vertical velocities which transport dust aloft and increase the atmospheric lifetime of these particles. For aerosol heating rates in the lowest levels, the shortwave effect prevails in the convection-permitting case with a net cooling effect, whereas a longwave net warming effect is present in the parameterized cases. The spread in dust concentrations across cumulus parameterizations at the same grid resolution (15 km) is an order of magnitude lower than the impact of moving from parameterized towards explicit convection. We conclude that tuning dust emissions in coarse-resolution simulations can only improve the results to first-order and cannot fully rectify the discrepancies originating from disparities in the representation of convective dust transport.</p>https://www.atmos-chem-phys.net/20/2967/2020/acp-20-2967-2020.pdf |
| spellingShingle | J. Bukowski S. C. van den Heever Convective distribution of dust over the Arabian Peninsula: the impact of model resolution Atmospheric Chemistry and Physics |
| title | Convective distribution of dust over the Arabian Peninsula: the impact of model resolution |
| title_full | Convective distribution of dust over the Arabian Peninsula: the impact of model resolution |
| title_fullStr | Convective distribution of dust over the Arabian Peninsula: the impact of model resolution |
| title_full_unstemmed | Convective distribution of dust over the Arabian Peninsula: the impact of model resolution |
| title_short | Convective distribution of dust over the Arabian Peninsula: the impact of model resolution |
| title_sort | convective distribution of dust over the arabian peninsula the impact of model resolution |
| url | https://www.atmos-chem-phys.net/20/2967/2020/acp-20-2967-2020.pdf |
| work_keys_str_mv | AT jbukowski convectivedistributionofdustoverthearabianpeninsulatheimpactofmodelresolution AT scvandenheever convectivedistributionofdustoverthearabianpeninsulatheimpactofmodelresolution |