A comparison of tilt current meters and an acoustic doppler current meter in vineyard sound, Massachusetts

The relatively high cost of acoustic current meters has placed practical limits on the use of these meters in marine research projects. One approach to reducing the cost of current measurements has been the re-invention of the Tilt Current Meter (TCM). Recent developments in accelerometers, magnetometers and low-power non-volatile memory have made it possible to make small, accurate and inexpensive TCMs. Here we describe the design and calibration of the Lowell Instruments TCM and validate its performance in Vineyard Sound, Massachusetts. The performance of four TCMs was compared to an acoustic Doppler current profiler reference meter. The TCMs exhibited an R squared correlation of 0.97-0.98 as well as low slope and offset errors. Based on this demonstrated accuracy we believe the TCM would be useful for a variety of research projects especially where there is a risk of instrument loss or where increased spatial density of measurements is desired.