Calculation of heat flux in a macrotidal flat using FVCOM

[1] To understand the effect of a tidal flat on the seawater temperature near a macrotidal flat, the heat flux was calculated using the unstructured grid, finite-volume coastal ocean model (FVCOM). For this study, a code for calculating the sediment temperature was added to include the heat exchange between seawater and the seabed. Seawater provides heat to the seabed at the intertidal zone (tidal flat) during the morning flood tide and gains heat from the seabed during the afternoon flood tide. The seawater heated by the atmosphere and seabed at the intertidal zone supplies heat to the sublittoral zone during spring, summer, and winter, but vice versa in autumn. The maximum heat supplied from the intertidal zone to the sublittoral zone was 13.85 × 106 GJ in May 2004, and the maximum heat gain from the sublittoral zone was 25.02 × 106 GJ in November 2003. The seawater at the intertidal zone gained 0.57 × 106 GJ (4.50 W m−2) and 14.06 × 106 GJ (112.03 W m−2) of heat from the seabed and atmosphere, respectively, in May 2004 and lost 0.61 × 106 GJ (4.86 W m−2) and 25.06 × 106 GJ (201.15 W m−2) of heat to the seabed and atmosphere, respectively, in November 2003.