Signatures of Tropical climate modes on the Red Sea and Gulf of Aden Sea Level

Abstract

Long–term sea level data (1958–2010) for the Red Sea (RS) and Gulf of Aden (GA) obtained from Simple Ocean Data Assimilation (SODA) were analyzed to examine its relation to the tropical climate modes. The continuous wavelet power spectrum analysis of sea level reflects the presence of significant power peak in semi-annual and annual band throughout the study region over the entire period. This variability is clearly associated with Nino3.4, which were accounted from the analysis of wavelet coherence. The results show an in-phase relation in semi-annual band while the sea level lags the Nino3.4 by 9-10 months in annual band in all regions, which in-turn is associated to the peak difference between mean SST and sea level. Whereas, there is no significant interaction is identified with SOI and IOD. However, the wavelet coherence of Nino3.4 and SOI showed 2-7 years band in all regions, which corresponds to the sequence of strong El Nino/La Nina events during1968-1976 and 1997-2003.