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| Two Northward Jumps of the Summertime Western Pacific Subtropical High and Their Associations with the Tropical SST Anomalies |
| SU Tong-Hua,XUE Feng |
| International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;Graduate University of Chinese Academy of Sciences, Beijing 100049,International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 |
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Abstract Based on the pentad mean ridgeline index of the western Pacific subtropical high (WPSH), the authors identified the two northward jumps of the WPSH from 1979 to 2008 and revealed their associations with the tropical SST anomalies. The authors show that the northward jumps, especially the second jump, exhibited remarkable interannual variability. In addition, the authors find that the two northward jumps were mutually independent and were influenced by the SST anomalies in the different regions of the tropical Pacific. The first jump was positively correlated with the SST anomalies in the tropical central Pacific from the preceding winter to June. In contrast, the second jump was positively related to ENSO in the preceding winter, but this correlation tended to weaken with the decay of ENSO and disappeared in July. Instead, a positive correlation was found in the Indian Ocean. We therefore suggest that ENSO plays an indirect role in the second jump through the capacitor effect of the Indian Ocean.
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Received: 08 December 2010
Revised: 11 January 2011
Accepted: 26 January 2011
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