Análise das correntes à superfície na região norte do canal de Moçambique

Abstract

This study was conceived with the aim of improving and understanding the oceanic and coastal circulation in the northern region of the Mozambique Channel, between parallels 10oS to 20oS. The results are considered of great importance for navigation and port operations along the coastal zone in Northern Mozambique, thus contributing to the monitoring of nautical activities and support of marine applications in this region of the Mozambican Channel. Analyzes of surface currents were carried out using data derived from satellite altimetry, at (0.25 x 0.25 degrees) spatial resolution and a time span of 15 years. A technique based on statistical calculations was used in the Spyder library of "Python" programming language, which allowed obtaining information of the large-scale current variability represented by the annual, seasonal averages associated with the standard deviation and Time Series taken in several stations along the Channel. With the stations along the Canal, it was intended to evaluate the variability of NEMC around the 11oS, to analyze the variability of the coastal current in the 15oS and 18oS bands and finally to 16oS to evaluate the variability of the currents in the northeast region of the Republic of Madagascar. The results of this study pointed out that at the entrance of the Mozambique Channel the North East Madagascar Current is variable with the greatest speeds of the order of 1m/s, persisting during summer. The instabilities of the NEMC were found to be responsible for the great variability dominating the western ends of the Channel, where the intermittent Mozambique Current (speeds of 0.6m/s) and the vortexes dominate the flow. Further to the north of the 11⸰S the NEMC oriented to the Mozambican coast was characterized as a very strong current, with speeds of 1m / s in the middle of each year, seasonal variations of intensity weaken this current reaching 0.7m / s and occasionally causing oscillations toward the north. In the 15⸰S the coastal current of Mozambique near continent has directions to the South and sometimes to the West for the period under analysis. This current is also quite strong, which by seasonality its velocity varies from 0 to 0.6m / s throughout the middle of each year. The north-eastern region of Madagascar 16⸰S is dominated by fairly weak current flowing at rates of 0.2m / s in varying directions and circulation in this region is dominated only by vortex fluctuations. In the Sofala Bank, precisely 18⸰S the coastal current near Mozambique is weak, maintaining speeds approximately 0.7m / s throughout each year, this current at the surface is associated to multidirectional variations due to the topography of the place.