@article{01JZHY4N74ZVFGJQB5DT9QQ059,
  abstract     = {{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 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.}},
  author       = {{Bush, Mike and Flack, David L. A. and Lewis, Huw W. and Bohnenstengel, Sylvia I. and Short, Chris J. and Franklin, Charmaine and Lock, Adrian P. and Best, Martin and Field, Paul and McCabe, Anne and Van Weverberg, Kwinten and Berthou, Segolene and Boutle, Ian and Brooke, Jennifer K. and Cole, Seb and Cooper, Shaun and Dow, Gareth and Edwards, John and Finnenkoetter, Anke and Furtado, Kalli and Halladay, Kate and Hanley, Kirsty and Hendry, Margaret A. and Hill, Adrian and Jayakumar, Aravindakshan and Jones, Richard W. and Lean, Humphrey and Lee, Joshua C. K. and Malcolm, Andy and Mittermaier, Marion and Mohandas, Saji and Moore, Stuart and Morcrette, Cyril and North, Rachel and Porson, Aurore and Rennie, Susan and Roberts, Nigel and Roux, Belinda and Sanchez, Claudio and Su, Chun-Hsu and Tucker, Simon and Vosper, Simon and Walters, David and Warner, James and Webster, Stuart and Weeks, Mark and Wilkinson, Jonathan and Whitall, Michael and Williams, Keith D. and Zhang, Hugh}},
  issn         = {{1991-959X}},
  journal      = {{GEOSCIENTIFIC MODEL DEVELOPMENT}},
  keywords     = {{ENVIRONMENT SIMULATOR JULES,ENSEMBLE SPREAD,CLOUD FRACTION,PART I,CLIMATE,SCHEME,PREDICTION,WEATHER,PRECIPITATION,KILOMETER}},
  language     = {{eng}},
  number       = {{12}},
  pages        = {{3819--3855}},
  title        = {{The third Met Office Unified Model-JULES Regional Atmosphere and Land configuration, RAL3}},
  url          = {{http://doi.org/10.5194/gmd-18-3819-2025}},
  volume       = {{18}},
  year         = {{2025}},
}

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