Impacts of tropical Indian Ocean SST on the meridional displacement of East Asian jet in boreal summer

Authors

  • Xia Qu,

    1. Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
    2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China
    3. Key Laboratory of Global Change and Marine-Atmospheric Chemistry, the Third Institute of Oceanography State Oceanic Administration, Xiamen 361005, China
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  • Gang Huang

    Corresponding author
    1. Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
    • RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
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Abstract

The meridional displacement of East Asia jet (EAJ) is characterized by the leading mode of upper tropospheric zonal wind variability over East Asia in boreal summer, and is closely related to the East Asia summer monsoon and downstream climate. Present study reveals that the meridional displacement of EAJ is associated with tropical Indian Ocean (TIO) SST anomalies. When the TIO SST is higher than normal, the overlying tropospheric air warms up through the modulation of the TIO SST on tropical convection. The anomalous convection forces a Kelvin wave wedge penetrating into the equatorial western Pacific, leading to a decrease in precipitation near the Philippines. Combined with the climatological easterly shear over the subtropical western North Pacific, the Pacific-Japan/East Asia-Pacific (PJ/EAP) teleconnection is induced along the East Asia coast. The PJ/EAP-related upper-level anomalous cyclone accelerates westerly in the south flank of EAJ and decelerates westerly in the north flank. Thus, EAJ shifts southward. In contrast, the EAJ shifts northward when the TIO SST is lower than normal. Copyright © 2011 Royal Meteorological Society

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