Association of the Sea–ice in Southern Indian Ocean with ENSO

In this paper the wavelet analysis of monthly mean satellite-derived Sea-Ice Extent (SIE) anomalies in the southern Indian Ocean and in the Antarctica region have been carried out for 22 years (1979-2000) of data. The study reveals that prior to major El Nino events, 2 to 4 and 6 to 8 modes in the SIE anomalies during winter (December-January- February) and spring (March- April-May) seasons are quite dominant and significant in both regions (southern Indian Ocean and Antarctica). The lag lead relationship between SIE and sea surface temperature (SST) anomalies over different Nino regions are also investigated and it is observed that winter time SIE anomaly in southern Indian Ocean shows a significant relationship with the succeeding year SST anomalies in Nino4 and Nino3.4 regions. The analysis of the zonal flow at 850hPa level (i.e. U anomaly field) over the three regions: east, west and central equatorial Pacific Ocean are also investigated. The study reveals that there is a strong inverse relationship between the SIE in southern Indian Ocean and U anomaly over west and central equatorial Pacific Ocean during winter and spring seasons.