• Adv. Atmos. Sci.
    Interannual Weakening of the Tropical Pacific Walker Circulation Due to Strong Tropical Volcanism
    Jiapeng MIAO1, 5, Tao WANG1, 2, Huijun WANG1, 3, 4, Jianqi SUN1, 2, 5
    1.Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
    2.Joint Laboratory for Climate and Environmental Change, Chengdu University of Information Technology, Chengdu 610225, China
    3.Key Laboratory of Meteorological Disaster, Nanjing University of Information Science and Technology, Nanjing, 210044, China
    4.Climate Change Research Center, Chinese Academy of Sciences, Beijing 100029, China
    5.University of Chinese Academy of Sciences, Beijing 100049, China
    Abstract  In order to examine the response of the tropical Pacific Walker circulation (PWC) to strong tropical volcanic eruptions (SVEs), we analyzed a three-member long-term simulation performed with HadCM3, and carried out four additional CAM4 experiments. We found that the PWC shows a significant interannual weakening after SVEs. The cooling effect from SVEs is able to cool the entire tropics. However, cooling over the Maritime Continent is stronger than that over the central-eastern tropical Pacific. Thus, non-uniform zonal temperature anomalies can be seen following SVEs. As a result, the sea level pressure gradient between the tropical Pacific and the Maritime Continent is reduced, which weakens trade winds over the tropical Pacific. Therefore, the PWC is weakened during this period. At the same time, due to the cooling subtropical and midlatitude Pacific, the Intertropical Convergence Zone (ITCZ) and South Pacific convergence zone (SPCZ) are weakened and shift to the equator. These changes also contribute to the weakened PWC. Meanwhile, through the positive Bjerknes feedback, weakened trade winds cause El Niño-like SST anomalies over the tropical Pacific, which in turn further influence the PWC. Therefore, the PWC significantly weakens after SVEs. The CAM4 experiments further confirm the influences from surface cooling over the Maritime Continent and subtropical/midlatitude Pacific on the PWC. Moreover, they indicate that the stronger cooling over the Maritime Continent plays a dominant role in weakening the PWC after SVEs. In the observations, a weakened PWC and a related El Niño-like SST pattern can be found following SVEs.
    Corresponding Authors: Tao WANG   
    Just Accepted Date: 18 January 2018  
    E-mail this article
    E-mail Alert
    Articles by authors
    Jiapeng MIAO
    Tao WANG
    Huijun WANG
    Jianqi SUN
    Cite this article:   
    Jiapeng MIAO,Tao WANG,Huijun WANG, et al. Interannual Weakening of the Tropical Pacific Walker Circulation Due to Strong Tropical Volcanism[J]. Adv. Atmos. Sci., 18 January 2018. [Epub ahead of print] doi: 10.1007/s00376-017-7134-y.
    URL:     OR
    [1] CHEN Longxun,ZHU Wenqin,ZHOU Xiuji,ZHOU Zijiang. Characteristics of the Heat Island Effect in Shanghai and Its Possible Mechanism[J]. , 2003, 20(6): 991 -1001 .