A comparative study of ocean surface interannual variability in Northern Tanzania and the Northern Kenya Bank

Majuto Manyilizu,Philip Sagero,Shigalla B Mahongo,Issufo Halo

doi:10.4314/wiojms.si2020.1.1

Abstract

The livelihoods of most residents of Tanga (Northern Tanzania) and Malindi (Northern Kenya), rely strongly on fishing activities in the East African shelf region. Thus, understanding variations in sea surface temperature (SST) and its related parameters such as thermocline depths and upper ocean circulation are crucial. This study applies a regional model to understand interannual spatial relationships between ocean circulation and SST off Northern Tanzania and on the Northern Kenya Bank. The results indicate slight differences in variations off the Northern Tanzanian shelf region and the Northern Kenya Bank. Such small variations might have local impacts on the human population through influencing primary productivity and fisheries. The coastal waters off Malindi indicate stronger variations, particularly in 1997 (cold SST) and 1998 (warm SST), than those off Tanga region. The SST anomalies seem to be associated with thermocline and sea surface height (SSH) off Malindi, while off Tanga they relate only to SSH. This information provides further understanding of parameters that may affect fishing activities in these regions and can be used for planning and management processes.

Highlights

Impacts of interannual variability of meteorological and oceanic characteristics on a region depend on the pre-existing climate and local characteristics of a particular region (Marchant et al, 2006)
The East African coast experiences interannual variability of parameters involved in air-sea interactions and ocean dynamics
The main activities for the majority of coastal residents in Tanga in Northern Tanzania and Malindi on the north coast of Kenya rely on fishing activity in the East African shelf region

Summary

Introduction

Impacts of interannual variability of meteorological and oceanic characteristics on a region depend on the pre-existing climate and local characteristics of a particular region (Marchant et al, 2006) Such impacts have been reported to be associated with variability of SST, precipitation and sea level pressures during different El Niño-Southern Oscillation (ENSO) events During an El Niño event, the tropical Indian Ocean warms and enhances precipitation in equatorial East Africa mainly during October-December following the first warming in the Pacific. Such enhanced precipitation leads to severe flooding in parts of East Africa (Schott et al, 2009). A good example of this scenario is the positive IOD and/or El Niño events in 1997/1998 that led to severe floods in parts of East Africa (Schott et al, 2009)

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Conclusion