Turbulence measurements with acoustic doppler current profilers: Do we gain improvements with high-resolution mode?

Turbulence measurements with acoustic doppler current profilers: Do we gain improvements with high-resolution mode? 

Supervisors

• Nicole Jones
  Associate Professor, Oceans Graduate School

Students

• Shangyu Wu

• Zihao Wang 

Project Description

Although Nortek claims the “Signature1000 acoustic Doppler current profiler (ADCP) is the optimal tool for turbulence measurements. With a maximum sampling frequency of 16 Hz that gives the scientific community an unprecedented opportunity to study a part of the turbulence spectrum that has never been accessible before.” We have struggled to adequately resolve the turbulence spectrum in Australian NWS deployments. However, we have not yet collected data using the high-resolution (HR) firmware that is available at an additional cost. Here we propose to compare the data output from a Signature1000 ADCP operating in regular mode with an instrument operating in the high-resolution mode. The results will allow us to determine if the HR firmware is a good investment.  

Impact

Resolving the turbulence in the water column is critical to understanding processes such as the vertical transport of materials such as nutrients and sediment. It is also important to understand boundary layer processes, which are critical to the assumptions behind design of near-bed offshore structures. The development of turbulence methodology from ADCP data will allow us to determine turbulence quantities at a vertical resolution of 2 cm across depths of ~10 m- a significant shift from our current point measurements with acoustic Doppler velocimeters.