Seasonal Variation of the Sea Surface Temperature Growth Rate of ENSO  

作　　者：Xinyi XING Xianghui FANG Da PANG Chaopeng JI 

机构地区：[1]Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences,Fudan University,Shanghai 200438,China [2]Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction,Shanghai 200438,China [3]Shanghai Key Laboratory of Ocean-land-atmosphere Boundary Dynamics and Climate Change,Fudan University,Shanghai 200438,China

出　　处：《Advances in Atmospheric Sciences》2024年第3期465-477,共13页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 42192564);Guangdong Major Project of Basic and Applied Basic Research (Grant No. 2020B0301030004);the Ministry of Science and Technology of the People's Republic of China (Grant No.2020YFA0608802)。

摘　　要：El Ni?o–Southern Oscillation(ENSO) exhibits a distinctive phase-locking characteristic, first expressed during its onset in boreal spring, developing during summer and autumn, reaching its peak towards winter, and decaying over the next spring. Several studies have demonstrated that this feature arises as a result of seasonal variation in the growth rate of ENSO as expressed by the sea surface temperature(SST). The bias towards simulating the phase locking of ENSO by many state-of-the-art climate models is also attributed to the unrealistic depiction of the growth rate. In this study, the seasonal variation of SST growth rate in the Ni?o-3.4 region(5°S–5°N, 120°–170°W) is estimated in detail based on the mixed layer heat budget equation and recharge oscillator model during 1981–2020. It is suggested that the consideration of a variable mixed layer depth is essential to its diagnostic process. The estimated growth rate has a remarkable seasonal cycle with minimum rates occurring in spring and maximum rates evident in autumn. More specifically, the growth rate derived from the meridional advection(surface heat flux) is positive(negative) throughout the year. Vertical diffusion generally makes a negative contribution to the evolution of growth rate and the magnitude of vertical entrainment represents the smallest contributor. Analysis indicates that the zonal advective feedback is regulated by the meridional immigration of the intertropical convergence zone, which approaches its southernmost extent in February and progresses to its northernmost location in September, and dominates the seasonal variation of the SST growth rate.

关 键 词：SST growth rate intertropical convergence zone zonal advective feedback mixed layer depth ENSO seasonal variation 

分 类 号：P732[天文地球—海洋科学]