How reliable are Coupled Model Intercomparison Project Phase 6 models in representing the Asian summer monsoon anticyclone?

Bhupendra Bahadur Singh*, Kondapalli Niranjan Kumar, Vivek Seelanki, Rama Krishna Karumuri, Raju Attada, Ravi Kumar Kunchala

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

We assess the Asian summer monsoon anticyclone (ASMA) in Coupled Model Intercomparison Project Phase 6 (CMIP6) models for the historical period (1850–2014). The ASMA is a quasi-stationary warm anticyclone during the boreal summer monsoon season, centred around Tibet. It is a prominent circulation feature that affects trace species transport, stratosphere–troposphere exchange, along with strong feedbacks to weather and climate. The study is a novel attempt to quantify the performance of models participating in the CMIP6 consortium and understand long-term variability and teleconnections of the ASMA. We note that CMIP6 models capture the mean ASMA features reasonably well, albeit with some differences around the edges. For most of the models, interannual variations are not in phase with the reanalysis and show sharper increasing trend in the ASMA strength. There is about a twofold increase in the trends during the recent period (1980–2014) as compared to the 1950–2014 period. A multimodel mean (MME) chosen based upon the statistical metrics (mean, standard deviation, mean absolute error and root-mean-square error), target diagram, and density distributions is further used to examine the prominent modes of variability. Our results suggest that the signals of significant periodicity, particularly the 2–4 years signal, and the SST correlations in MME are inconsistent with observations. In CMIP6 models, we note stronger upper level divergence over the western and eastern Pacific but convergence over the Indian ocean, South Asia and the central Pacific. The streamfunction and rotational winds also show strong highs north of 20°N. Overall, it is seen that basic features such as spatial extent and evolution of ASMA are reasonably captured, but the strength and interannual variations are dissonant across the CMIP6 models. These findings are useful for studies focusing on regional meteorology, transportation of atmospheric tracers and climate change projections over the region involving the ASMA.

Original languageEnglish (US)
Pages (from-to)7047-7059
Number of pages13
JournalInternational Journal of Climatology
Volume42
Issue number13
DOIs
StatePublished - Nov 15 2022

Bibliographical note

Funding Information:
The authors thank the World Climate Research Programme (WCRP) for making CMIP6 model data publicly available. We extend our thanks to the climate modelling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the data and providing access. We also acknowledge ECMWF and NCEP/NCAR for providing reanalysis data. We thank anonymous reviewers whose comments and suggestions have improved the manuscript.

Publisher Copyright:
© 2022 Royal Meteorological Society.

Keywords

  • Asian summer monsoon anticyclone
  • CMIP6
  • teleconnections
  • wavelet spectrum

ASJC Scopus subject areas

  • Atmospheric Science

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