Fig 3 - uploaded by Tor Gammelsrød
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Schematic view of the system. Panel a) shows variations in x, while panel b) shows a cross section of reef, indicating different depths for a situation near low tide.
Source publication
Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 kmÂ0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the cur...
Contexts in source publication
Context 1
... simplified model for the circulation in the lagoon at Xai-Xai is defined, where constant density is assumed and Coriolis forces are neglected. Fig. 3 shows a schematic of the system. The x-axis is placed parallel to the reef, with positive direction east-northeast (cf. Fig. 1). The model domain is closed on the left end, has a length of 1700 m and a width B varying in the range 80e200 m. The reef is about 20 m wide and defines a straight line. Inside the reef is an alongshore ...
Context 2
... a transport of water across the reef V(x,t), caused by wave and a pressure gradient due to cross-reef sea level differences. Inside the lagoon, most waves have dissipated, and we ignore second-order wave effects, that is, setup/setdown inside and outside of the lagoon, or the excitation of low frequency (infra- gravity) waves (e.g., edge waves). Fig. 3b shows a cross section of the model lagoon. Sea surface heights are given as the deviation from a mean sea level. Table 1 contains a list of the parameters used in the model. ...
Similar publications
Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 km×0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the cur...
Citations
... Most of the instruments used in this study have also been used in field experiments at Xai-Xai Beach, and are described more in detail in Christensen et al. (2013). A brief overview is given below for completeness. ...
This report summarizes the 2013 field experiment at Tofo Beach, Tofo, Inhambane, in which measurements of bottom topography, currents, sea level, and surface waves were collected. A visual assessment of the surrounding areas was also made, and some comments are made concerning the morphology at Tofo Beach.
Keywords: Nearshore dynamics, beach morphology
... 1. A second field survey was performed in Xai-Xai in October 2012 close to spring tide (Christensen et al., 2013). Point measurements of current velocity inside the lagoon (Fig. 1) were obtained using an Aanderaa SeaGuard moored at a depth of about 1 m below surface. ...
Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 km×0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the current, but sea surface height tends to be overestimated at high tide, especially during high wave events. Inside the lagoon we observed a mainly uni-directional alongshore current, with speeds up to 1 ms−1. The current varies primarily with the tide, being close to zero near low tide, generally increasing during flood and decreasing during ebb. The observations revealed a local minimum in the alongshore flow at high tide, which the model was successful in reproducing. Residence times in the lagoon were calculated to be less than one hour with wave forcing dominating the flushing. At this beach a high number of drowning casualties have occurred, but no connection was found between them and strong current events in a simulation covering the period 2011-2012.
