COMPARISON OF TURBULENCE KINETIC-ENERGY DISSIPATION RATE ESTIMATES FROM 2 OCEAN MICROSTRUCTURE PROFILERS

Almost 1000 microstructure profiles from two separate groups on two se parate ships using different instrumentation, signal processing, and c alibration procedures were compared for a 3.5-day time period at 0 deg rees 140 degrees W and within 11 km of each other. Systematic bias in the estimates of epsilon is less than a factor of 2, which is within e stimates of the cumulative uncertainties in the measurement of epsilon . Although there is no evidence for strong gradients in mean currents, water properties, or surface meteorology, occasional hourly averages of epsilon differ by several factors of 10. Both groups observed perio ds where epsilon estimates exceeded those of the other group by large factors. The authors believe that the primary reason for these large d ifferences is natural variability, which appears to be greater in the meridional direction than in the zonal direction.