ESSO - Indian National Centre for Ocean Information Services
(An Autonomous Body under the Ministry of Earth Sciences, Govt. of India)
E-Publications
| Paper No | 1 | Publication ID : 739 & Year : 2019 |
| Title | Wyrtki Jets: Role of intraseasonal forcing | |
| Authors | S Prerna , Abhisek Chatterjee , A Mukherjee , M Ravichandran and S S C Shenoi | |
| Source | J. Earth Syst. Sci., Doi.org/10.1007/s12040-018-1042-0 | |
| Abstract | 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 MaddenâżżJulian 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. | |