The connection between the Atlantic multidecadal oscillation and the Indian summer monsoon in CMIP5 models
- 348 Downloads
A number of observational and modeling studies have shown a co-relationship between higher than normal sea surface temperatures (SSTs) in the North Atlantic and increased summer precipitation over India. However, discrepancies among the models make the robustness of the results debatable. This study examines the connections between the Atlantic multidecadal oscillation (AMO) and the Indian summer monsoon (ISM) in 66 “Historical” runs of 22 coupled models that were part of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Diverse results are obtained, and correlation coefficients between the AMO and ISM range from − 0.39 to 0.66. Only 10 out of 66 members (~ 15%) show a positive correlation statistically significant at the 90% level (> 0.42), close to the observation (0.5). The models with positive AMO–ISM correlations show an AMO-related atmospheric teleconnection that involves an extratropical–tropical SST gradient in the North Pacific, as well as a more regional temperature difference between the Indian subcontinent and the tropical Indian Ocean. In comparison, the models with negative correlations fail to capture these teleconnections. Moreover, the models with higher climatological precipitation over the tropical Atlantic and warmer climatological SST in the tropical Atlantic and the North Pacific relative to multi-member ensemble, as well as a weak westerly jet, perform better at reproducing the observed teleconnections.
This study was jointly supported by the Natural Science Foundation of China (41790473 and 41731177), the MOST key project (2016YFA0601802), the Natural Science Foundation of China (41375085 and 41421004), and the Strategic Project of the Chinese Academy of Sciences (Grant XDA11010401). This study also contributes to the Research Council of Norway supported project IndiaClim (no. 216554). We acknowledge the two anonymous reviewers for their valuable comments and suggestions that help to greatly improve the manuscript.
- Compo G, Whitaker J, Sardeshmukh P, Matsui N, Allan R, Yin X, Gleason B, Vose R, Rutledge G, Bessemoulin P, Bronnimann S, Brunet M, Crouthamel R, Grant A, Groisman P, Jones P, Kruk M, Kruger A, Marshall G, Maugeri M, Mok H, Nordli O, Ross T, Trigo R, Wang X, Woodruff S, Worley S (2011) The twentieth century reanalysis project. Q J R Meteorol Soc 137:1–28. https://doi.org/10.1002/qj.776 CrossRefGoogle Scholar
- Drinkwater KF, Miles M, Medhaug I, Otterå OH, Kristiansen T, Sundby S, Gao Y (2014) The Atlantic multidecadal oscillation: its manifestations and impacts with special emphasis on the Atlantic region north of 60 N. J Mar Syst 133:117–130. https://doi.org/10.1016/j.jmarsys.2013.11.001 CrossRefGoogle Scholar
- Keenlyside NS, Ba J, Mecking J, Omrani NO, Latif M, Zhang R, Msadek R (2015) North Atlantic multi-decadal variability-mechanisms and predictability. In: Chang C-P, Ghil M, Latif M, Wallace M (eds) Climate change: multidecadal and beyond. World Scientific Publishing Company, Singapore. ISBN 978–9814579926CrossRefGoogle Scholar
- Rajeevan M, Bhate J, Kale J, Lal B (2006) High resolution daily gridded rainfall data for the Indian region: analysis of break and active monsoon spells. Curr Sci 91(3):296–306Google Scholar