Influence of the Tropical Atlantic on the Western North Pacific Subtropical High in the Boreal Summer

• Main Authors: Tao-Chi Chang, 張道奇
• Other Authors: 許晃雄
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/82229547738779037552

碩士 === 國立臺灣大學 === 大氣科學研究所 === 101 === In this study, we target on the interannual relationship between the Western North Pacific Subtropical High (WNPSH) and the Tropical Atlantic sea surface temperature (SST) in the boreal summer. We find that the interannual variance of the WNPSH has become significantly larger after the early 1980s. The interannual correlation between the WNPSH index and global SST is also characterized by a shift on the late 1970s and early 1980s. SST is one of the important factors that affect the WNPSH. The effects of the SST fluctuation in the Northern Indian Ocean (NIO), the Western Pacific (WP), Marine Continent (MC) and the Equatorial Center Pacific (ECP) have been widely examined in recent years. But the effect of the Tropical Atlantic (TA) was hardly explored. The result of correlation analysis with the TA SST shows a quadrupole structure of streamfunction over Pacific and Indian Ocean. Using SVD analysis, we find the variability modes with the circulation patterns associated with the quadrupole structure of streamfunction and the corresponding SST pattern with warm SST in TA and NIO and cold SST in WNP. We think this mode is similar to the air-ocean interaction mode which found by Wang et al. (2013) via Principal Component Analysis. Numerical experiments using the ICTP AGCM/slab ocean model (Kucharski et al., 2013) confirm that the warm TA SST can cause the descending flow by Walker Circulation over the WNP, and also influence the NIO-WNP coupling system in the boreal summer, therefore enhance WNPSH directly and indirectly.