An evaluation of the thermal properties and albedo of a macrotidal flat

The thermal properties of sediment and the albedo are critical in calculating the heat flux of a tidal flat. However, they are not well known because of the difficulties of sampling and observing tidal flats. We use extensive field observations of a macrotidal flat on the western coast of Korea to determine its sediment heat capacity and albedo. The estimated heat capacity of the upper 0.1 m is 3.65 × 106 J m−3 K−1 with a water content of 70%. Heat capacity decreases with depth to 2.96 × 106 J m−3 K−1 at 0.4 m depth. Estimated thermal diffusivities are 0.47–0.63 × 10−6 m2 s−1 and 0.38–0.64 × 10−6 m2 s−1 in spring and summer, respectively. The calculated albedo is a strong function of the solar altitude and the atmospheric transmittance. Atmospheric transmittance is especially important to the albedo when the solar altitude is low. Seasonal mean albedos are 0.13 and 0.15 in spring and summer, respectively. The heat capacity and albedo values obtained above were verified by using them to make independent heat flux estimates at other stations. Estimates based on heat capacity were correlated to albedo‐based heat flux estimates with an r2 greater than 0.7.