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Journal of Southern Hemisphere Earth Systems Science Journal of Southern Hemisphere Earth Systems Science SocietyJournal of Southern Hemisphere Earth Systems Science Society
A journal for meteorology, climate, oceanography, hydrology and space weather focused on the southern hemisphere
RESEARCH ARTICLE (Open Access)

Impacts of the new UM convection scheme, CoMorph-A, over the Indo-Pacific and Australian regions

Hongyan Zhu https://orcid.org/0000-0002-9824-3347 A * , Debra Hudson A , Chen Li https://orcid.org/0000-0002-3811-4236 A , Li Shi A , Bethan White A , Griffith Young A , Alison Stirling B , Michael Whitall B , Adrian Lock B , Sally Lavender C and Rachel Stratton B
+ Author Affiliations
- Author Affiliations

A The Bureau of Meteorology, GPO Box 1289, Melbourne, Vic. 3001, Australia.

B Met Office, Exeter, EX1 3PB, UK.

C Centre for Applied Climate Sciences, University of Southern Queensland, Brisbane, Qld 4072, Australia.

* Correspondence to: hongyan.zhu@bom.gov.au

Handling Editor: Peter May

Journal of Southern Hemisphere Earth Systems Science 74, ES23011 https://doi.org/10.1071/ES23011
Submitted: 12 May 2023  Accepted: 24 July 2024  Published: 2 September 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the Bureau of Meteorology. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

A new convection scheme, ‘CoMorph-A’, has been introduced into the latest UK Met Office coupled (GC4) and atmosphere-only (GA8) models. In this study, the impact of CoMorph-A is assessed in atmosphere-only Atmospheric Model Intercomparison Project simulations, as well as in sets of initialised 28-day forecasts with both the coupled and uncoupled models. Initial results show improvements over the Indo-Pacific and northern Australian regions, as well as improvements in the rainfall bias, Madden–Julian Oscillation simulation and prediction, tropical cyclone forecasts and the diurnal cycle of rainfall over the Maritime Continent. The improvements are mostly consistent across the initialised forecasts and the climate simulations, indicating the effectiveness of the new scheme across applications. The use of this new convection scheme is promising for future model configurations, and for improving the simulation and prediction of Australian weather and climate. The UK Met Office is continuing to develop CoMorph and will soon release version B.

Keywords: Australia weather and climate, CoMorph, convection scheme, diurnal cycle, Madden–Julian Oscillation, MJO, model biases, tropical cyclone, UK Met Office global model, UM.

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