Watterson, IG, Keane, RJ orcid.org/0000-0002-7506-7352, Dix, M et al. (3 more authors) (2021) Analysis of CMIP6 atmospheric moisture fluxes and the implications for projections of future change in mean and heavy rainfall. International Journal of Climatology, 41 (S1). E1417-E1434. ISSN 0899-8418
Abstract
Motivated by the wide range of projections of regional rainfall (or precipitation, pr) based on the CMIP5 ensemble of global climate models, we investigate the atmospheric moisture budget of idealized rising‐CO2 (1pctCO2) simulations from 10 models submitted to CMIP6. We use the new CMIP6 standard variables, the vertically integrated eastward and northward moisture flux, and provide a multi‐model assessment of these, their convergence (conv), along with water vapour path (prw). Seasonal climatologies of a 20‐year base climate for pr, prw, flux, and conv match well those from the ECMWF's Reanalysis 5. In addition, composites ‘H’ of quantities for months in the top decile of monthly rainfall, calculated at each model grid point, produce a field of heavy rainfall, on average double that of the mean. Spatial correlation coefficients (r) between the pr and conv fields are typically .7 in each season. This rises to .9 for the corresponding H fields, due to the important link between moisture convergence and heavy rainfall. Fields of standardized change (Δ), or change per degree of global warming, were calculated. The ensemble‐mean Δpr is only weakly correlated with the base climate pr, and likewise for conv. However, the prw change is highly correlated with the base prw, pointing to the importance of the “thermodynamic” change in that variable. Globally, the net Δconv is highly correlated with Δpr, around .9. This rises to .95 for the heavy‐rain composites. Relationships between changes in pr and other components hold at grid points also, when the individual model results are correlated. Clearly, there is a dependence in the change in pr with that in conv, particularly for heavy rainfall. Assessment of a larger ensemble from CMIP6, using the new flux variables, would improve the evaluation of these processes, and potentially allow more confident projections in future rainfall changes.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2020 Royal Meteorological Society. This is the peer reviewed version of the following article: Watterson, IG, Keane, RJ , Dix, M et al. (3 more authors) (2021) Analysis of CMIP6 atmospheric moisture fluxes and the implications for projections of future change in mean and heavy rainfall. International Journal of Climatology, 41 (S1). E1417-E1434. ISSN 0899-8418, which has been published in final form at https://doi.org/10.1002/joc.6777. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. |
Keywords: | atmospheric moisture transport; climate change; heavy precipitation |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Oct 2020 08:49 |
Last Modified: | 19 Jul 2022 09:07 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/joc.6777 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:166532 |