El Niño-East Asian Summer Monsoon teleconnection and its diversity: simulations and future projections in CMIP5 models
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AbstractThe impacts of two types of El Niño on the East Asian Summer Monsoon (EASM) in the present and the future climate have been investigated, using historical and representative concentration pathway 8.5 (RCP 8.5) simulations from 31 models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). Before examining the future characteristics of El Nino diversity and its climate impacts, the model historical runs were carefully assessed, focusing on their ability to reproduce the time mean patterns and interannual variability of the tropical Pacific sea surface temperature (SST) as well as the EASM circulation. Only 9 out of 31 models were found to be able to capture both the El Niño diversity and EASM variability. While all of the 9 models can reproduce the large-scale atmospheric overturning over the Pacific during eastern-Pacific (EP) El Niño, only 5 of them can capture realistic Walker circulation anomalies and teleconnection characteristics of central-Pacific (CP) El Niño. Further analyses showed that the ability in reproducing El Nino-related teleconnection is affected by biases in the SST over the central-eastern equatorial Pacific; apparently models with strong cold tongue biases tend to have a westward shift of their diabatic heating during CP El Nino, thereby affecting the teleconnection effect in the model environment. For future projections of the impact of El Niño on EASM, it was found that the amplitudes of EASM anomalous precipitation will be enhanced significantly, for both types of El Nino and regardless of models’ SST biases. Moisture budget analyses showed that, under a warmer climate, both the change of EASM anomalous wind circulation and a moister atmosphere are equally important to account for more variable precipitation during El Nino events.
All Author(s) ListPeng Wang, Chi-Yung Tam, Kang Xu
Name of ConferenceAsia Oceania Geosciences Society 15th Annual Meeting
Start Date of Conference03/06/2018
End Date of Conference08/06/2018
Place of ConferenceHonolulu
Country/Region of ConferenceUnited States of America
LanguagesEnglish-United States

Last updated on 2018-23-10 at 14:51