The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3
<p>The third version of the Regional Atmosphere and Land (RAL3) science configuration is documented. Developed through international partnerships, RAL configurations define settings for the Unified Model atmosphere and Joint UK Land Environment Simulator (JULES) when applied across timescales...
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Copernicus Publications
2025-06-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/18/3819/2025/gmd-18-3819-2025.pdf |
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| author | M. Bush D. L. A. Flack H. W. Lewis S. I. Bohnenstengel C. J. Short C. Franklin A. P. Lock M. Best P. Field A. McCabe K. Van Weverberg K. Van Weverberg K. Van Weverberg S. Berthou I. Boutle J. K. Brooke S. Cole S. Cooper G. Dow J. Edwards A. Finnenkoetter K. Furtado K. Halladay K. Hanley M. A. Hendry A. Hill A. Jayakumar R. W. Jones H. Lean J. C. K. Lee A. Malcolm M. Mittermaier S. Mohandas S. Moore C. Morcrette R. North A. Porson S. Rennie N. Roberts B. Roux C. Sanchez C.-H. Su S. Tucker S. Vosper D. Walters J. Warner S. Webster M. Weeks J. Wilkinson M. Whitall K. D. Williams H. Zhang |
| author_facet | M. Bush D. L. A. Flack H. W. Lewis S. I. Bohnenstengel C. J. Short C. Franklin A. P. Lock M. Best P. Field A. McCabe K. Van Weverberg K. Van Weverberg K. Van Weverberg S. Berthou I. Boutle J. K. Brooke S. Cole S. Cooper G. Dow J. Edwards A. Finnenkoetter K. Furtado K. Halladay K. Hanley M. A. Hendry A. Hill A. Jayakumar R. W. Jones H. Lean J. C. K. Lee A. Malcolm M. Mittermaier S. Mohandas S. Moore C. Morcrette R. North A. Porson S. Rennie N. Roberts B. Roux C. Sanchez C.-H. Su S. Tucker S. Vosper D. Walters J. Warner S. Webster M. Weeks J. Wilkinson M. Whitall K. D. Williams H. Zhang |
| author_sort | M. Bush |
| collection | DOAJ |
| description | <p>The third version of the Regional Atmosphere and Land (RAL3) science configuration is documented. Developed through international partnerships, RAL configurations define settings for the Unified Model atmosphere and Joint UK Land Environment Simulator (JULES) when applied across timescales with kilometre and sub-kilometre-scale model grids. The RAL3 configuration represents a major advance compared to previous versions by delivering a common science definition suitable for application to tropical and mid-latitude regions. Developments within RAL3 include the introduction of a double-moment microphysics scheme and a bimodal cloud scheme, replacing use of a single-moment scheme and different cloud schemes for mid-latitudes and tropics in previous versions. Updates have been implemented to the boundary layer scheme and a consolidation of land model settings to be more consistent with global atmosphere and land (GAL) science configurations. Physics developments aimed to address priorities for model performance improvement identified by users. This paper documents the RAL3 science configuration, including a series of iterative revisions delivered since its first release, and their characteristics. Evidence is provided from the variety of assessments of RAL3, relative to the previous version (RAL2). Collaborative development and evaluation across organizations have enabled evaluation across a range of domains, grid spacing and timescales. The analysis indicates more realistic precipitation distributions, improved representation of clouds and of visibility, a continued trend to more realistic representation of convection, and reduced near-surface wind speeds but a persistent cold-temperature bias. Overall the convective-scale verification scores and climatological model distributions relative to observations improve for the majority of variables. Ensemble results show improvements to the spread–error relationship. User feedback from subjective assessment activities has also been positive. Differences between RAL3 revisions and RAL2 are further<span id="page3820"/> illustrated through a process-based analysis of a convective system over the UK. The latest RAL3 configuration (RAL3.3) is therefore recommended for research, operational numerical weather prediction, and climate production at kilometre and sub-kilometre scales.</p> |
| format | Article |
| id | doaj-art-ee9768fc71fa4837a04c282c23e531c1 |
| institution | Kabale University |
| issn | 1991-959X 1991-9603 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj-art-ee9768fc71fa4837a04c282c23e531c12025-08-20T03:27:36ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032025-06-01183819385510.5194/gmd-18-3819-2025The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3M. Bush0D. L. A. Flack1H. W. Lewis2S. I. Bohnenstengel3C. J. Short4C. Franklin5A. P. Lock6M. Best7P. Field8A. McCabe9K. Van Weverberg10K. Van Weverberg11K. Van Weverberg12S. Berthou13I. Boutle14J. K. Brooke15S. Cole16S. Cooper17G. Dow18J. Edwards19A. Finnenkoetter20K. Furtado21K. Halladay22K. Hanley23M. A. Hendry24A. Hill25A. Jayakumar26R. W. Jones27H. Lean28J. C. K. Lee29A. Malcolm30M. Mittermaier31S. Mohandas32S. Moore33C. Morcrette34R. North35A. Porson36S. Rennie37N. Roberts38B. Roux39C. Sanchez40C.-H. Su41S. Tucker42S. Vosper43D. Walters44J. Warner45S. Webster46M. Weeks47J. Wilkinson48M. Whitall49K. D. Williams50H. Zhang51Met Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMetOffice@Reading, Brian Hoskins building, Earley Gate, University of Reading, Reading, RG6 6BB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKBureau of Meteorology, Melbourne, Victoria, AustraliaMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKnow at: Royal Meteorological Institute of Belgium, Brussels, Belgiumnow at: Department of Geography, Ghent University, Ghent, BelgiumMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKBureau of Meteorology, Melbourne, Victoria, AustraliaMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMeteorological Service Singapore (MSS), P.O. Box 8, Changi Airport, 918141, SingaporeMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMetOffice@Reading, Brian Hoskins building, Earley Gate, University of Reading, Reading, RG6 6BB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKNational Centre for Medium Range Weather Forecasting (NCMRWF), Noida, IndiaMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMetOffice@Reading, Brian Hoskins building, Earley Gate, University of Reading, Reading, RG6 6BB, UKMeteorological Service Singapore (MSS), P.O. Box 8, Changi Airport, 918141, SingaporeMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKNational Centre for Medium Range Weather Forecasting (NCMRWF), Noida, IndiaNational Institute of Water & Atmospheric Research Ltd (NIWA), 301 Evans Bay Parade, Greta Point, Wellington, 6021, New ZealandMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMetOffice@Reading, Brian Hoskins building, Earley Gate, University of Reading, Reading, RG6 6BB, UKBureau of Meteorology, Melbourne, Victoria, AustraliaMetOffice@Reading, Brian Hoskins building, Earley Gate, University of Reading, Reading, RG6 6BB, UKBureau of Meteorology, Melbourne, Victoria, AustraliaMet Office, FitzRoy Road, Exeter, EX1 3PB, UKBureau of Meteorology, Melbourne, Victoria, AustraliaMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMet Office, FitzRoy Road, Exeter, EX1 3PB, UKMeteorological Service Singapore (MSS), P.O. Box 8, Changi Airport, 918141, Singapore<p>The third version of the Regional Atmosphere and Land (RAL3) science configuration is documented. Developed through international partnerships, RAL configurations define settings for the Unified Model atmosphere and Joint UK Land Environment Simulator (JULES) when applied across timescales with kilometre and sub-kilometre-scale model grids. The RAL3 configuration represents a major advance compared to previous versions by delivering a common science definition suitable for application to tropical and mid-latitude regions. Developments within RAL3 include the introduction of a double-moment microphysics scheme and a bimodal cloud scheme, replacing use of a single-moment scheme and different cloud schemes for mid-latitudes and tropics in previous versions. Updates have been implemented to the boundary layer scheme and a consolidation of land model settings to be more consistent with global atmosphere and land (GAL) science configurations. Physics developments aimed to address priorities for model performance improvement identified by users. This paper documents the RAL3 science configuration, including a series of iterative revisions delivered since its first release, and their characteristics. Evidence is provided from the variety of assessments of RAL3, relative to the previous version (RAL2). Collaborative development and evaluation across organizations have enabled evaluation across a range of domains, grid spacing and timescales. The analysis indicates more realistic precipitation distributions, improved representation of clouds and of visibility, a continued trend to more realistic representation of convection, and reduced near-surface wind speeds but a persistent cold-temperature bias. Overall the convective-scale verification scores and climatological model distributions relative to observations improve for the majority of variables. Ensemble results show improvements to the spread–error relationship. User feedback from subjective assessment activities has also been positive. Differences between RAL3 revisions and RAL2 are further<span id="page3820"/> illustrated through a process-based analysis of a convective system over the UK. The latest RAL3 configuration (RAL3.3) is therefore recommended for research, operational numerical weather prediction, and climate production at kilometre and sub-kilometre scales.</p>https://gmd.copernicus.org/articles/18/3819/2025/gmd-18-3819-2025.pdf |
| spellingShingle | M. Bush D. L. A. Flack H. W. Lewis S. I. Bohnenstengel C. J. Short C. Franklin A. P. Lock M. Best P. Field A. McCabe K. Van Weverberg K. Van Weverberg K. Van Weverberg S. Berthou I. Boutle J. K. Brooke S. Cole S. Cooper G. Dow J. Edwards A. Finnenkoetter K. Furtado K. Halladay K. Hanley M. A. Hendry A. Hill A. Jayakumar R. W. Jones H. Lean J. C. K. Lee A. Malcolm M. Mittermaier S. Mohandas S. Moore C. Morcrette R. North A. Porson S. Rennie N. Roberts B. Roux C. Sanchez C.-H. Su S. Tucker S. Vosper D. Walters J. Warner S. Webster M. Weeks J. Wilkinson M. Whitall K. D. Williams H. Zhang The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 Geoscientific Model Development |
| title | The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 |
| title_full | The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 |
| title_fullStr | The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 |
| title_full_unstemmed | The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 |
| title_short | The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3 |
| title_sort | third met office unified model jules regional atmosphere and land configuration ral3 |
| url | https://gmd.copernicus.org/articles/18/3819/2025/gmd-18-3819-2025.pdf |
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