Thermal waves in a nearshore environment

Long time series of temperature data for air, water and bottom sediment were obtained with a vertical thermistor array in a fixed location in shallow coastal water off southern California. Statistical techniques are employed to determine the amplitude and phase of the thermal waves from the air-sea interface through the water column and into the sediment layer. The long period thermal waves are dominated, nominally, by annual, semi-annual and monthly periodicities. Results obtained using the classical solution with constant conductivity agree well with the experimental data for the annual thermal wave but for the semi-annual and monthly waves the agreement, in the water column, is poor. Theoretical results obtained using an eddy heat conductivity that varied exponentially with depth agree well with experimental results for the annual, semi-annual and monthly thermal waves.