Acquisition and Processing of LADCP Data

This is the Lamont page relating to the acquisition and processing of data from Lowered Acoustic Doppler Current Profiler (LADCP) instruments. It is maintained by Andreas M. Thurnherr.

LADCP Processing Software

In order to remove the effects of instrument motion from the velocity measurements obtained by LADCP systems, elaborate data processing is required. There are two fundamentally different methods used for this purpose: The shear method described by Firing and Gordon (1990) and by Fischer and Visbeck [J. Tech. 1993], and the velocity inversion method described by Visbeck [J. Tech. 2002]. Thurnherr maintains implementations of both methods, available from this server:

Velocity Inversion Version IX. This software, which is the official LADCP data processing software used during CLIVAR, was originally written by M. Visbeck. Thurnherr wrote a user interface, a manual and has been maintaining the software and providing user support since 2004.

Re-Implementation of the UH Shear Method. One of the main reasons why use of LADCP systems became widespread during the WOCE was the pioneering processing software written and maintained by E. Firing and his group at the University of Hawai'i. Because the UH implementation is somewhat cumbersome to set up and use, and because it is no longer supported, Thurnherr re-implemented a slightly simplified version of this software. The new implementation of the shear method is intended, in particular, for use in shear-based finestructure parameterizations and for processing tow-yo and yo-yo casts.

LADCP Acquisition Software for RDI ADCPs

Most instruments used for LADCP work are manufactured by Teledyne/RDI, who provide DOS and Windows software for communicating with the instruments (for setup and data downloading). In order to avoid having to use a Microsoft operating system, Thurnherr implemented a portable data acquisition system for RDI ADCPs based entirely on popular public-domain tools. Data acquisition is controlled by a set of expect scripts, which use a perl-based program (called bbabble) to communicate with one or two RDI ADCPs. The LDEO LADCP data acquisitions software is available from this server.

Manuals

GO-SHIP Manual for Acquiring Lowered Doppler Current Profiler Data [Thurnherr, A. M. Visbeck, E. Firing, B. King, J. Hummon, G. Krahman and B. Huber, 2009]

How to Process LADCP Data with LDEO Software Version IX [A.M. Thurnherr, 2004]


© 2012 A.M. Thurnherr (e-mail)created: Tue Sep 11 11:35:39 2012 modified: Tue Sep 11 12:07:29 2012