DOI: 10.25349/d9mw50
title: AUV observations of Langmuir turbulence in a stratified shelf sea

description: Measurements collected by a REMUS 600 AUV off the coast of southern
 California demonstrate large-scale coherent wave-driven vortices,
 consistent with Langmuir turbulence (LT), played a dominant role in
 structuring turbulent dissipation within the oceanic surface boundary
 layer. During a 10-hour period with sustained wind speeds of 10 m/s,
 Langmuir circulations were limited to the upper third of the surface mixed
 layer by persistent stratification within the water column. The
 ensemble-averaged circulation, calculated using conditional averaging of
 AD2CP velocity profiles using elevated backscattering intensity associated
 with subsurface bubble clouds, indicates that LT vortex pairs were
 characterized by an energetic downwelling zone flanked by broader, weaker
 upwelling regions with vertical velocity magnitudes similar to previous
 numerical studies of LT. Horizontally-distributed microstructure estimates
 of turbulent kinetic energy dissipation rates were lognormally-distributed
 near the surface in the wave mixing layer with the majority of values
 falling between wall layer scaling and wave transport layer scaling.
 Partitioning dissipation rates between downwelling centers and ambient
 conditions suggests that LT may play a dominant role in elevating
 dissipation rates in the OSBL by redistributing wave-breaking turbulence.
description: # AUV observations of Langmuir turbulence in a stratified shelf sea
 [https://doi.org/10.25349/D9MW50](https://doi.org/10.25349/D9MW50) ##
 Description of the data and file structure This archive contains data
 collected off the coast of Santa Barbara, CA in May 2022 as described in
 section 2 of Fisher, A. W., & Nidzieko, N. J. (2024). AUV Observations
 of Langmuir Turbulence in a Stratified Shelf Sea. *Journal of Physical
 Oceanography*. doi.org/10.1175/JPO-D-23-0136.1. Data are provided as
 MATLAB .mat files and all timestamps are in UTC. ### Files and variables
 #### File: data\_archive.zip **Folders & Description:**  *
 \GB4A_Airmar\ surface meteorological conditions measured by an Airmar
 200WX mounted on the GB4A transponder buoy * \Nortek_Signature1000\
 Acoustic current profiles, backscatter intensity, and inertial
 measurements used in the characterization of Langmuir cell structure and
 circulation. Raw measurements are provided as well as data which has been
 motion corrected and converted to a ENU reference frame as described in
 section 2a of the paper. Motion-corrected ENU data are contained within
 files with the suffix *_cor.mat. While INS data from the Kearfott T24 data
 is not included in these files, but was used in the coordinate
 transformation and motion correction, such data is available from the
 authors upon request. * \REMUS\ House instrumentation from the REMUS 600
 vehicle, which includes the following subdirectories * \ADCP\ measured
 water velocities in vicinity of the vehicle from upward and downward
 looking 600kHz ADCPs * \BATHY\ bottom-tracking from downward looking ADCP
 * \CTD\ temperature, conductivity, pressure measurements * \GPSDATA\ GPS
 fix data acquired during mission circuit * \STATE\ house variables
 describing vehicle state and attitude * \220511_adc_clean\ processed ADCP
 current profiles from upward and downward looking ADCPs. -
 \RSI_MicroRider1000\ Turbulent microstructure measurements from a Rockland
 Scientific Microrider-1000 equipped with shear probes, microconductivity
 sensor, and fast thermistor. Raw data in RSI .P files are provided in
 addition to .mat files that have been converted using Rockland ODAS
 version 4.5.1 - \Sofar-Spotter\ CSV files containing the raw wave
 measurements from SoFar Spotter exported using sd_file_parser v1.7.12.py
 provided by SoFar Ocean. See python code for description of output file
 structure.