Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Representation of Modes of Variability in Six U.S. Climate Models

TitleRepresentation of Modes of Variability in Six U.S. Climate Models
Publication TypeJournal Article
Year of Publication2020
AuthorsOrbe, Clara, Van Roekel Luke, Adames Angel F., Dezfuli Amin, Fasullo John, Gleckler Peter J., Lee Jiwoo, Li Wei, Nazarenko Larissa, Schmidt Gavin A., Sperber Kenneth R., and Zhao Ming
JournalJournal of Climate
Volume33
Number17
Pages7591-7617
Abstract / Summary

We compare the performance of several modes of variability across six U.S. climate modeling groups, with a focus on identifying robust improvements in recent models [including those participating in phase 6 of the Coupled Model Intercomparison Project (CMIP)] compared to previous versions. In particular, we examine the representation of the Madden–Julian oscillation (MJO), El Niño–Southern Oscillation (ENSO), the Pacific decadal oscillation (PDO), the quasi-biennial oscillation (QBO) in the tropical stratosphere, and the dominant modes of extratropical variability, including the southern annular mode (SAM), the northern annular mode (NAM) [and the closely related North Atlantic Oscillation (NAO)], and the Pacific–North American pattern (PNA). Where feasible, we explore the processes driving these improvements through the use of “intermediary” experiments that utilize model versions between CMIP3/5 and CMIP6 as well as targeted sensitivity experiments in which individual modeling parameters are altered. We find clear and systematic improvements in the MJO and QBO and in the teleconnection patterns associated with the PDO and ENSO. Some gains arise from better process representation, while others (e.g., the QBO) from higher resolution that allows for a greater range of interactions. Our results demonstrate that the incremental development processes in multiple climate model groups lead to more realistic simulations over time.

URLhttp://dx.doi.org/10.1175/jcli-d-19-0956.1
DOI10.1175/jcli-d-19-0956.1
Journal: Journal of Climate
Year of Publication: 2020
Volume: 33
Number: 17
Pages: 7591-7617
Publication Date: 09/2020

We compare the performance of several modes of variability across six U.S. climate modeling groups, with a focus on identifying robust improvements in recent models [including those participating in phase 6 of the Coupled Model Intercomparison Project (CMIP)] compared to previous versions. In particular, we examine the representation of the Madden–Julian oscillation (MJO), El Niño–Southern Oscillation (ENSO), the Pacific decadal oscillation (PDO), the quasi-biennial oscillation (QBO) in the tropical stratosphere, and the dominant modes of extratropical variability, including the southern annular mode (SAM), the northern annular mode (NAM) [and the closely related North Atlantic Oscillation (NAO)], and the Pacific–North American pattern (PNA). Where feasible, we explore the processes driving these improvements through the use of “intermediary” experiments that utilize model versions between CMIP3/5 and CMIP6 as well as targeted sensitivity experiments in which individual modeling parameters are altered. We find clear and systematic improvements in the MJO and QBO and in the teleconnection patterns associated with the PDO and ENSO. Some gains arise from better process representation, while others (e.g., the QBO) from higher resolution that allows for a greater range of interactions. Our results demonstrate that the incremental development processes in multiple climate model groups lead to more realistic simulations over time.

DOI: 10.1175/jcli-d-19-0956.1
Citation:
Orbe, C, L Van Roekel, A Adames, A Dezfuli, J Fasullo, P Gleckler, J Lee, et al.  2020.  "Representation of Modes of Variability in Six U.S. Climate Models."  Journal of Climate 33(17): 7591-7617.  https://doi.org/10.1175/jcli-d-19-0956.1.