A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment,...A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment, with fixed radiative forcing, is conducted to evaluate the DIOD variability and its relationship with the TPDV. In this experiment, the sea surface temperature anomalies are restored to observations over the tropical Pacific, but left as interactive with the atmosphere elsewhere. The TPDV-forced DIOD, represented as the ensemble mean of 10 simulations in POGA, accounts for one third of the total variance. The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback. Thermocline anomalies do not exhibit a propagating signal, indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean. The DIOD-TPDV correlation differs among the 10 simulations, with a low correlation corresponding to a strong internal DIOD independent of the TPDV. The variance of this internal DIOD depends on the background state in the Indian Ocean, modulated by the thermocline depth off Sumatra/Java.展开更多
ENSO induces coherent climate anomalies over the Indo-western Pacific, but these anomalies outlast SST anomalies of the equatorial Pacific by a season, with major effects on the Asian summer monsoon. This review provi...ENSO induces coherent climate anomalies over the Indo-western Pacific, but these anomalies outlast SST anomalies of the equatorial Pacific by a season, with major effects on the Asian summer monsoon. This review provides historical accounts of major milestones and synthesizes recent advances in the endeavor to understand summer variability over the Indo-Northwest Pacific region. Specifically, a large-scale anomalous anticyclone （AAC） is a recurrent pattern in post-E1 Nifio summers, spanning the tropical Northwest Pacific and North Indian oceans. Regarding the ocean memory that anchors the summer AAC, competing hypotheses emphasize either SST cooling in the easterly trade wind regime of the Northwest Pacific or SST warming in the westerly monsoon regime of the North Indian Ocean. Our synthesis reveals a coupled ocean- atmosphere mode that builds on both mechanisms in a two-stage evolution. In spring, when the northeast trades prevail, the AAC and Northwest Pacific cooling are coupled via wind-evaporation-SST feedback. The Northwest Pacific cooling persists to trigger a summer feedback that arises from the interaction of the AAC and North Indian Ocean warming, enabled by the westerly monsoon wind regime. This Indo-western Pacific ocean capacitor （IPOC） effect explains why E1 Nifio stages its last act over the monsoonal Indo-Northwest Pacific and casts the Indian Ocean warming and AAC in leading roles. The IPOC displays interdecadal modulations by the ENSO variance cycle, significantly correlated with ENSO at the turn of the 20th century and after the 1970s, but not in between. Outstanding issues, including future climate projections, are also discussed.展开更多
基金supported by National Key R&D Program of China(2016YFA0601803)National Natural Science Foundation of China(NSFC)project(41606008,41525019)+3 种基金the State Oceanic Administration of China(GASI-IPOVAI-02)the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(Project No.LTO1603)the Japan Society for the Promotion of Science[Grantin-Aid for Young Scientists(A)JP15H05466]and the Japanese Ministry of Environment(Environment Research and Technology Development Fund 2-1503)
文摘A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment, with fixed radiative forcing, is conducted to evaluate the DIOD variability and its relationship with the TPDV. In this experiment, the sea surface temperature anomalies are restored to observations over the tropical Pacific, but left as interactive with the atmosphere elsewhere. The TPDV-forced DIOD, represented as the ensemble mean of 10 simulations in POGA, accounts for one third of the total variance. The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback. Thermocline anomalies do not exhibit a propagating signal, indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean. The DIOD-TPDV correlation differs among the 10 simulations, with a low correlation corresponding to a strong internal DIOD independent of the TPDV. The variance of this internal DIOD depends on the background state in the Indian Ocean, modulated by the thermocline depth off Sumatra/Java.
基金supported by the National Basic Research Program of China (Grant No. 2012CB 955600)the U.S. National Science Foundation, the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA11010103)+1 种基金the Environment Research and Technology Development Fund 2-1503 of the Japanese Ministry of Environment, the Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research 25287120 and for Young Scientists 15H05466the National Natural Science Foundation of China (Grant Nos. 41205049, 41275081, 41425019, 41525019, 41521005)
文摘ENSO induces coherent climate anomalies over the Indo-western Pacific, but these anomalies outlast SST anomalies of the equatorial Pacific by a season, with major effects on the Asian summer monsoon. This review provides historical accounts of major milestones and synthesizes recent advances in the endeavor to understand summer variability over the Indo-Northwest Pacific region. Specifically, a large-scale anomalous anticyclone （AAC） is a recurrent pattern in post-E1 Nifio summers, spanning the tropical Northwest Pacific and North Indian oceans. Regarding the ocean memory that anchors the summer AAC, competing hypotheses emphasize either SST cooling in the easterly trade wind regime of the Northwest Pacific or SST warming in the westerly monsoon regime of the North Indian Ocean. Our synthesis reveals a coupled ocean- atmosphere mode that builds on both mechanisms in a two-stage evolution. In spring, when the northeast trades prevail, the AAC and Northwest Pacific cooling are coupled via wind-evaporation-SST feedback. The Northwest Pacific cooling persists to trigger a summer feedback that arises from the interaction of the AAC and North Indian Ocean warming, enabled by the westerly monsoon wind regime. This Indo-western Pacific ocean capacitor （IPOC） effect explains why E1 Nifio stages its last act over the monsoonal Indo-Northwest Pacific and casts the Indian Ocean warming and AAC in leading roles. The IPOC displays interdecadal modulations by the ENSO variance cycle, significantly correlated with ENSO at the turn of the 20th century and after the 1970s, but not in between. Outstanding issues, including future climate projections, are also discussed.
