This study focuses on the interdecadal changes in ENSO properties emerging around the year 2000. Compared to 1980-1999, after 2000, the ENSO amplitude weakened, the occurrence of the central Pacific （CP） Et Nino inc...This study focuses on the interdecadal changes in ENSO properties emerging around the year 2000. Compared to 1980-1999, after 2000, the ENSO amplitude weakened, the occurrence of the central Pacific （CP） Et Nino increased, and the eastern Pacific （EP） El Nino became suppressed. Meanwhile, the dominant period of ENSO shortened from quasi-quadrennial （QQ） to quasi-biennial （QB）. The authors show that these changes in ENSO properties are evidently consistent with the change in the stability of the ENSO mode through connecting the two ENSO types with the two coupled ENSO modes, i.e. the QQ and QB modes. It is suggested that the relative activity or stability of the two ENSO modes changed after the year 2000. The intensity of both the QQ and QB mode weakened. The QQ mode, which is linked to EP ENSO and was significantly strong during 1980-1999, became much weaker after 2000 in terms of the EP type almost disappearing. Compared with the weakness of the QQ mode, the QB mode, as manifested by the CP type, remained active and became dominant in the tropical Pacific after 2000. Analysis shows that the changes in mean states in the tropical Pacific were likely responsible for the interdecadal ENSO changes around the year 2000.展开更多
This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is str...This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is strong during high correlation(HC)periods,e.g.1957–1964 and 1981–2004,but weak during low correlation(LC)periods,e.g.1907–1924,1926–1956,1965–1980,and2005–2008.The surface air–sea coupling and the evolution of subsurface ocean temperature anomaliesh along the equatorial Paci?c associated with the VM are found to be strong during HC periods and weak during LC periods,which results in a stronger impact of the VM on the following-winter ENSO during HC periods.The interdecadal change in the relationship between the VM and ENSO is mainly due to the interdecadal change in the intensity of the VM,which is found to be in?uenced by the North Paci?c Oscillation.Our?ndings may improve the prediction skill for the onset of ENSO events.展开更多
The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO)....The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO).However,there is no consensus yet on its anomalous impacts on the phase and amplitude of ENSO.Based on data during 1982-2022,results show that anomalies of the antisymmetric mode can affect the evolution of ENSO on the interannual scale via Bjerknes feedback,in which the positive(negative)phase of the antisymmetric mode can strengthen El Niño(La Niña)in boreal winter via an earlier(delayed)seasonal cycle transition and larger(smaller)annual mean.The magnitude of the SST anomalies in the equatorial eastern Pacific can reach more than±0.3◦C,regulated by the changes in the antisymmetric mode based on random sensitivity analysis.Results reveal the spatial pattern of the annual cycle associated with the seasonal phase-locking of ENSO evolution and provide new insight into the impact of the annual cycle of background SST on ENSO,which possibly carries important implications for forecasting ENSO.展开更多
Zonal wind stress plays an important role in the evolution of El Ni（n）o-Southern Oscillation （ENSO） events;however,a comprehensive comparison and analysis in terms of model performance and related bias in the inte...Zonal wind stress plays an important role in the evolution of El Ni（n）o-Southern Oscillation （ENSO） events;however,a comprehensive comparison and analysis in terms of model performance and related bias in the interannual variability of zonal wind stress across the tropical Pacific has yet to be performed.In this study,the authors evaluate how well the individual atmospheric models participating in phase 5 of the Coupled Model Intercomparison Project simulate zonal wind stress.It is found that the wind stress anomalies simulated by the multi-model ensemble are weaker than those in the observation in both El Ni（n）o and La Ni（n）a events,with a larger bias in the former.Further analysis indicates that the bias associated with El Ni（n）o events may be mainly attributable to the weaker negative precipitation anomalies in the AMIP simulations,compared with observations,over the eastern Indian Ocean.Through the Gill-like responses in atmospheric circulation,the rainfall bias over the eastern Indian Ocean results in an easterly wind stress anomaly in the western and central equatorial Pacific,which to some extent offsets the westerly wind stress anomalies associated with El Ni（n）o events.Consequently,the responses of zonal wind stress anomalies to warm SST anomalies are much underestimated in AMIP simulations during El Niffo events.展开更多
基金jointly supported by the China Meteorological Special Projects[grant number GYHY201506013]the National Basic Reaseach Program of China(973)[grant number2015CB453203]+1 种基金the National Natural Science Foundation of China[grant numbers 41405080 and 41375062]partly supported by the UK-China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership China as part of the Newton Fund
文摘This study focuses on the interdecadal changes in ENSO properties emerging around the year 2000. Compared to 1980-1999, after 2000, the ENSO amplitude weakened, the occurrence of the central Pacific （CP） Et Nino increased, and the eastern Pacific （EP） El Nino became suppressed. Meanwhile, the dominant period of ENSO shortened from quasi-quadrennial （QQ） to quasi-biennial （QB）. The authors show that these changes in ENSO properties are evidently consistent with the change in the stability of the ENSO mode through connecting the two ENSO types with the two coupled ENSO modes, i.e. the QQ and QB modes. It is suggested that the relative activity or stability of the two ENSO modes changed after the year 2000. The intensity of both the QQ and QB mode weakened. The QQ mode, which is linked to EP ENSO and was significantly strong during 1980-1999, became much weaker after 2000 in terms of the EP type almost disappearing. Compared with the weakness of the QQ mode, the QB mode, as manifested by the CP type, remained active and became dominant in the tropical Pacific after 2000. Analysis shows that the changes in mean states in the tropical Pacific were likely responsible for the interdecadal ENSO changes around the year 2000.
基金supported by the National Natural Science Foundation of China [grant number 41790474]the National Program on Global Change and Air–Sea Interaction[grant numbers GASI-IPOVAI-06 and GASI-IPOVAI-03]the National Key Technology Research and Development Program of the Ministry of Science and Technology of China [grant number 2015BAC03B07]
文摘This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is strong during high correlation(HC)periods,e.g.1957–1964 and 1981–2004,but weak during low correlation(LC)periods,e.g.1907–1924,1926–1956,1965–1980,and2005–2008.The surface air–sea coupling and the evolution of subsurface ocean temperature anomaliesh along the equatorial Paci?c associated with the VM are found to be strong during HC periods and weak during LC periods,which results in a stronger impact of the VM on the following-winter ENSO during HC periods.The interdecadal change in the relationship between the VM and ENSO is mainly due to the interdecadal change in the intensity of the VM,which is found to be in?uenced by the North Paci?c Oscillation.Our?ndings may improve the prediction skill for the onset of ENSO events.
基金jointly supported by the National Natural Science Foundation of China [grant numbers U2242205 and 41830969]the S&T Development Fund of CAMS [grant number 2023KJ036]the Basic Scientific Research and Operation Foundation of CAMS [grant number 2023Z018]。
文摘The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO).However,there is no consensus yet on its anomalous impacts on the phase and amplitude of ENSO.Based on data during 1982-2022,results show that anomalies of the antisymmetric mode can affect the evolution of ENSO on the interannual scale via Bjerknes feedback,in which the positive(negative)phase of the antisymmetric mode can strengthen El Niño(La Niña)in boreal winter via an earlier(delayed)seasonal cycle transition and larger(smaller)annual mean.The magnitude of the SST anomalies in the equatorial eastern Pacific can reach more than±0.3◦C,regulated by the changes in the antisymmetric mode based on random sensitivity analysis.Results reveal the spatial pattern of the annual cycle associated with the seasonal phase-locking of ENSO evolution and provide new insight into the impact of the annual cycle of background SST on ENSO,which possibly carries important implications for forecasting ENSO.
基金supported by the National Natural Science Foundation of China[grant number 41530426]
文摘Zonal wind stress plays an important role in the evolution of El Ni（n）o-Southern Oscillation （ENSO） events;however,a comprehensive comparison and analysis in terms of model performance and related bias in the interannual variability of zonal wind stress across the tropical Pacific has yet to be performed.In this study,the authors evaluate how well the individual atmospheric models participating in phase 5 of the Coupled Model Intercomparison Project simulate zonal wind stress.It is found that the wind stress anomalies simulated by the multi-model ensemble are weaker than those in the observation in both El Ni（n）o and La Ni（n）a events,with a larger bias in the former.Further analysis indicates that the bias associated with El Ni（n）o events may be mainly attributable to the weaker negative precipitation anomalies in the AMIP simulations,compared with observations,over the eastern Indian Ocean.Through the Gill-like responses in atmospheric circulation,the rainfall bias over the eastern Indian Ocean results in an easterly wind stress anomaly in the western and central equatorial Pacific,which to some extent offsets the westerly wind stress anomalies associated with El Ni（n）o events.Consequently,the responses of zonal wind stress anomalies to warm SST anomalies are much underestimated in AMIP simulations during El Niffo events.
