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...
Published in: | Atmospheric Chemistry and Physics |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2014
|
Subjects: | |
Online Access: | https://doi.org/10.5194/acp-14-4749-2014 https://doaj.org/article/fabfce69e1cf4e8cbab6574793670d57 |
id |
ftdoajarticles:oai:doaj.org/article:fabfce69e1cf4e8cbab6574793670d57 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:fabfce69e1cf4e8cbab6574793670d57 2023-05-15T17:40:16+02:00 Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model J. P. Mulcahy D. N. Walters N. Bellouin S. F. Milton 2014-05-01T00:00:00Z https://doi.org/10.5194/acp-14-4749-2014 https://doaj.org/article/fabfce69e1cf4e8cbab6574793670d57 EN eng Copernicus Publications http://www.atmos-chem-phys.net/14/4749/2014/acp-14-4749-2014.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-14-4749-2014 https://doaj.org/article/fabfce69e1cf4e8cbab6574793670d57 Atmospheric Chemistry and Physics, Vol 14, Iss 9, Pp 4749-4778 (2014) Physics QC1-999 Chemistry QD1-999 article 2014 ftdoajarticles https://doi.org/10.5194/acp-14-4749-2014 2022-12-31T00:22:20Z 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 Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 14 9 4749 4778 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 J. P. Mulcahy D. N. Walters N. Bellouin S. F. Milton Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
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 |
J. P. Mulcahy D. N. Walters N. Bellouin S. F. Milton |
author_facet |
J. P. Mulcahy D. N. Walters N. Bellouin S. F. Milton |
author_sort |
J. P. Mulcahy |
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://doi.org/10.5194/acp-14-4749-2014 https://doaj.org/article/fabfce69e1cf4e8cbab6574793670d57 |
genre |
north slope Alaska |
genre_facet |
north slope Alaska |
op_source |
Atmospheric Chemistry and Physics, Vol 14, Iss 9, Pp 4749-4778 (2014) |
op_relation |
http://www.atmos-chem-phys.net/14/4749/2014/acp-14-4749-2014.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-14-4749-2014 https://doaj.org/article/fabfce69e1cf4e8cbab6574793670d57 |
op_doi |
https://doi.org/10.5194/acp-14-4749-2014 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
14 |
container_issue |
9 |
container_start_page |
4749 |
op_container_end_page |
4778 |
_version_ |
1766141148969041920 |