Wyrtki Jets: Role of intraseasonal forcing

Journal of earth system science

Prerna S^1¹  Abhisek Chatterjee^1² 

[1] Indian National Centre for Ocean Information Services, Hyderabad 500 090, India.^1;National Centre for Antarctic and Ocean Research, Goa 403 804, India.^2

关键词: Indian Ocean;    equatorial dynamics;    MJO;    zonal currents;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Direct current measurements observed from the acoustic Doppler current profilers in the equatorial Indian Ocean (EIO) and solutions from an ocean general circulation model are investigated to understand the dynamics of the Wyrtki jet. These jets are usually described as semiannual direct wind forced zonal currents along the central and eastern EIO. We show that both, spring and fall, Wyrtki jets show predominant semiannual spectral peaks, but significant intraseasonal energy is evident during spring in the central and eastern EIO. We find that for the semiannual band, there is a strong spectral coherence between the overlying winds and the currents in the central EIO, but no coherency is observed in the eastern part of the EIO. Moreover, for the intraseasonal band, strong coherency between the winds and currents is evident. During spring, intraseasonal currents induced by the Madden–Julian oscillation (MJO) superimpose constructively with semiannual currents and thus intensify the strength of the spring Wyrtki jet. Also, the atmospheric intraseasonal variability accounts for the interannual variabilities observed in spring Wyrtki jets.

【 授权许可】

CC BY