The hectometric modelling challenge: Gaps in the current state of the art and ways forward towards the implementation of 100‐m scale weather and climate models

Humphrey W. Lean, Natalie E. Theeuwes, Michael Baldauf, Jan Barkmeijer, Geoffrey Bessardon, Lewis Blunn, Jelena Bojarova, Ian A. Boutle, Peter A. Clark, Matthias Demuzere, Peter Dueben, Inger‐Lise Frogner, Siebren de Haan, Dawn Harrison, Chiel van Heerwaarden, Rachel Honnert, Adrian Lock, Chiara Marsigli, Valéry Masson, Anne Mccabe, Maarten van Reeuwijk, Nigel Roberts, Pier Siebesma, Petra Smolíková, Xiaohua Yang

Quarterly Journal of the Royal Meteorological Society · 2024

Abstract

For a number of years research has been carried out in several centres which has demonstrated the potential benefits of 100-m scale models for a range of meteorological phenomena. More recently, some meteorological services have started to consider seriously the operational implementation of practical hec- tometric models. Many, but by no means all, of the applications are likely to relatetourbanareas,wheretheenhancedresolutionhasobviousbenefits.This articleisconcernedwiththeissuesthatneedtobeaddressedtobridgethegap betweenresearchat100-mscalesandpracticalmodels.Wehighlightanumber ofkeyissuesthatneedtobeaddressed,withsuggestionsofimportantavenues forfuturedevelopment.Anoverarchingissueisthehighcomputationalcostof thesemodels.Althoughsomeideastoreducethisarepresented,itwillalways beaseriousconstraint.Thismeansthatthebenefitsofthesemodelsoverlower resolution ones, or other techniques for generating high-resolution forecasts, willneedtobeclearlyunderstood,aswillthetrade-offswithresolution.Wedis- cussissueswithmodeldynamicalcoresandphysics–dynamicscoupling.There are a number of challenges around model parameterisations, where some of thetraditionalproblems(e.g.,convection)becomeeasierbutanumberofnew HumphreyW.LeanandNatalieE.Theeuwescontributedequallytothisstudy. Foraffiliationsrefertopage29 This is an open access article under the terms of theCreative Commons Attribution-NonCommercialLicense, which permits use, distribution and reproduction in any medium,providedtheoriginalworkisproperlycitedandisnotusedforcommercialpurposes. © 2024 Crown copyright and The Author(s).Quarterly Journal of the Royal Meteorological Society published by John Wiley & Sons Ltd on behalf of Royal Meteorological Society.ThisarticleispublishedwiththepermissionoftheControllerofHMSOandtheKing’sPrinterforScotland. Q J R Meteorol Soc.2024;1–38. wileyonlinelibrary.com/journal/qj 1 2 LEANetal. challenges(e.g.,around surface parameterisations)appear.Observational data atthesescalespresentachallengeandn

Funding

• 101137851
• 437467569