Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model.
The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of short-range weather forecasts. In this study the impacts of increasing the aerosol com...
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ftunivreading:oai:centaur.reading.ac.uk:38687 2024-09-09T19:58:45+00:00 Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. Mulcahy, J.P. Walters, D.N. Bellouin, N. Milton, S.F. 2014-05-13 text https://centaur.reading.ac.uk/38687/ https://centaur.reading.ac.uk/38687/1/2014_mulcahy_acp.pdf http://www.atmos-chem-phys.net/14/4749/2014/acp-14-4749-2014.html en eng Copernicus Publications https://centaur.reading.ac.uk/38687/1/2014_mulcahy_acp.pdf Mulcahy, J.P., Walters, D.N., Bellouin, N. <https://centaur.reading.ac.uk/view/creators/90005006.html> orcid:0000-0003-2109-9559 and Milton, S.F. (2014) Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. Atmospheric Chemistry and Physics, 14. pp. 4749-4778. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-14-4749-2014 <https://doi.org/10.5194/acp-14-4749-2014> cc_by Article PeerReviewed 2014 ftunivreading https://doi.org/10.5194/acp-14-4749-2014 2024-07-09T14:07:01Z The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of short-range weather forecasts. In this study the impacts of increasing the aerosol complexity in the global NWP configuration of the Met Office Unified Model (MetUM) are investigated. A hierarchy of aerosol representations are evaluated including three-dimensional monthly mean speciated aerosol climatologies, fully prognostic aerosols modelled using the CLASSIC aerosol scheme and finally, initialised aerosols using assimilated aerosol fields from the GEMS project. The prognostic aerosol schemes are better able to predict the temporal and spatial variation of atmospheric aerosol optical depth, which is particularly important in cases of large sporadic aerosol events such as large dust storms or forest fires. Including the direct effect of aerosols improves model biases in outgoing long-wave radiation over West Africa due to a better representation of dust. However, uncertainties in dust optical properties propagate to its direct effect and the subsequent model response. Inclusion of the indirect aerosol effects improves surface radiation biases at the North Slope of Alaska ARM site due to lower cloud amounts in high-latitude clean-air regions. This leads to improved temperature and height forecasts in this region. Impacts on the global mean model precipitation and large-scale circulation fields were found to be generally small in the short-range forecasts. However, the indirect aerosol effect leads to a strengthening of the low-level monsoon flow over the Arabian Sea and Bay of Bengal and an increase in precipitation over Southeast Asia. Regional impacts on the African Easterly Jet (AEJ) are also presented with the large dust loading in the aerosol climatology enhancing of the heat low over West Africa and weakening the AEJ. This study highlights the importance of including a more realistic treatment of ... Article in Journal/Newspaper north slope Alaska CentAUR: Central Archive at the University of Reading Atmospheric Chemistry and Physics 14 9 4749 4778 |
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CentAUR: Central Archive at the University of Reading |
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ftunivreading |
language |
English |
description |
The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of short-range weather forecasts. In this study the impacts of increasing the aerosol complexity in the global NWP configuration of the Met Office Unified Model (MetUM) are investigated. A hierarchy of aerosol representations are evaluated including three-dimensional monthly mean speciated aerosol climatologies, fully prognostic aerosols modelled using the CLASSIC aerosol scheme and finally, initialised aerosols using assimilated aerosol fields from the GEMS project. The prognostic aerosol schemes are better able to predict the temporal and spatial variation of atmospheric aerosol optical depth, which is particularly important in cases of large sporadic aerosol events such as large dust storms or forest fires. Including the direct effect of aerosols improves model biases in outgoing long-wave radiation over West Africa due to a better representation of dust. However, uncertainties in dust optical properties propagate to its direct effect and the subsequent model response. Inclusion of the indirect aerosol effects improves surface radiation biases at the North Slope of Alaska ARM site due to lower cloud amounts in high-latitude clean-air regions. This leads to improved temperature and height forecasts in this region. Impacts on the global mean model precipitation and large-scale circulation fields were found to be generally small in the short-range forecasts. However, the indirect aerosol effect leads to a strengthening of the low-level monsoon flow over the Arabian Sea and Bay of Bengal and an increase in precipitation over Southeast Asia. Regional impacts on the African Easterly Jet (AEJ) are also presented with the large dust loading in the aerosol climatology enhancing of the heat low over West Africa and weakening the AEJ. This study highlights the importance of including a more realistic treatment of ... |
format |
Article in Journal/Newspaper |
author |
Mulcahy, J.P. Walters, D.N. Bellouin, N. Milton, S.F. |
spellingShingle |
Mulcahy, J.P. Walters, D.N. Bellouin, N. Milton, S.F. Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
author_facet |
Mulcahy, J.P. Walters, D.N. Bellouin, N. Milton, S.F. |
author_sort |
Mulcahy, J.P. |
title |
Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
title_short |
Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
title_full |
Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
title_fullStr |
Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
title_full_unstemmed |
Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. |
title_sort |
impacts of increasing the aerosol complexity in the met office global numerical weather prediction model. |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://centaur.reading.ac.uk/38687/ https://centaur.reading.ac.uk/38687/1/2014_mulcahy_acp.pdf http://www.atmos-chem-phys.net/14/4749/2014/acp-14-4749-2014.html |
genre |
north slope Alaska |
genre_facet |
north slope Alaska |
op_relation |
https://centaur.reading.ac.uk/38687/1/2014_mulcahy_acp.pdf Mulcahy, J.P., Walters, D.N., Bellouin, N. <https://centaur.reading.ac.uk/view/creators/90005006.html> orcid:0000-0003-2109-9559 and Milton, S.F. (2014) Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model. Atmospheric Chemistry and Physics, 14. pp. 4749-4778. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-14-4749-2014 <https://doi.org/10.5194/acp-14-4749-2014> |
op_rights |
cc_by |
op_doi |
https://doi.org/10.5194/acp-14-4749-2014 |
container_title |
Atmospheric Chemistry and Physics |
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14 |
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9 |
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4749 |
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4778 |
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1809929810302992384 |