Seasonal and interannual variability of surface chlorophyll-a and sea surface temperature in the Delgoa Bight, southern Mozambique

Dove, Veronica Fernando

Seasonal and interannual variability of surface chlorophyll-a and sea surface temperature in the Delgoa Bight, southern Mozambique

Master Thesis

2015

Publisher

University of Cape Town

Department

Department of Oceanography

Faculty

Faculty of Science

Abstract

Multi satellite data for surface chlorophyll‐a (Chl‐a), sea surface temperature (SST), sea surface wind (SSW) and sea level anomalies (SLA) have been obtained and analysed over the Delagoa Bight (24‐28°S, 32‐36°E), southern Mozambique for the period 2003‐2012 at monthly time scales. Both descriptive and quantitative analysis using wavelets have been used to obtain a better understanding of the nature of the interannual, seasonal and intra- seasonal variability of the data. Strong seasonal structure and interannual modulation were observed in the area averaged Chl‐a concentration and SST. The lowest maximum in monthly Chl-a was in December (0.127 mg.m--‐3) and the highest in August (0.541 mg.m‐3). The lowest maximum in monthly SST was in August (21.8°C) and the maximum in February (27.9°C). The Chl‐a and SST were strongly anti-correlated and both exhibited a well- defined seasonal cycle, contrasting with the SSW and SLA. The daily observations of temperature at 17 meters depth, from the northern Delagoa Bight at Ponta Zavora (24.48°S- 35.24°E) for the period 2006‐2011, have confirmed a seasonal signal with amplitude of about 6.5°C. Cool coastal water events were found mostly in summer and spring, with maximum amplitude of 6°C. Further analysis of this daily data did not reveal the timing of such events to be regular.

Keywords

Physical Oceanography

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