MALTA: A Zonally-Averaged Global Atmospheric Transport Model for Long-lived Trace Gases

Luke M Western*, Scott Bachman, S. A. Montzka, Matthew L Rigby

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review


We present a two-dimensional, zonally averaged global model of atmospheric transport named MALTA: Model of Averaged in Longitude Transport in the Atmosphere. It aims to be accessible to a broad community of users, with the primary function of quantifying emissions of greenhouse gases and ozone depleting substances. The model transport is derived from meteorological reanalysis data and flux-gradient experiments using a three-dimensional transport model. Atmospheric sinks are prescribed loss frequency fields. The zonally averaged model simulates important large-scale transport features such as the influence on trace gas concentrations of the quasi-biennial oscillation and variations in inter-hemispheric transport rates. Stratosphere-troposphere exchange is comparable to a three-dimensional model and inter-hemispheric transport is faster by up to 0.3 years than typical transport times of three-dimensional models, depending on the metric used. Validation of the model shows that it can estimate emissions of CFC-11 from an incorrect a priori emissions field well using three-dimensional (3D) mole fraction fields generated using a different 3D model than which the flux gradient relationships were derived. The model is open source and is expected to be applicable to a wide range of studies requiring a fast, simple model of atmospheric transport and chemical processes for estimating associated emissions or mole fractions.
Original languageEnglish
Article numbere2023MS003909
Number of pages17
JournalJournal of Advances in Modeling Earth Systems
Issue number5
Publication statusPublished - 2 May 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Journal of Advances in Modeling Earth Systems published by Wiley Periodicals LLC on behalf of American Geophysical Union.


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