A New Quasi-Horizontal Glider to Measure Biophysical Microstructure

This study describes the development of a new tethered quasi-horizontal microstructure profiler: the Turbulence Ocean Microstructure Acquisition Profiler‐Glider [TurboMAP-Glider (TMG)]. It is a unique instrument, capable of measuring ocean microstructure (temperature and turbulent velocity shear), chlorophyll, and turbidity simultaneously through a quasi-horizontal perspective. Three field experiments were carried out near Joga-shima, Japan, to test the TMG flight performance, and those results as well as comparisons with a laser-based vertical profiler, TurboMAP-L (TM), are described here. The TMG was capable of flying with an angle of attack of less than 258 and was reasonably stable for up to 300m horizontally over 100-m depth. Some new and relevant empirical results about quasi-horizontal application of high-resolution chlorophyll-afluorescencesensorsarepresented.TheratiobetweentheThorpelengthscaleandtheOzmidov lengthscalewasusedasatracertodemonstratethatmostoftheTMGdensityinversions areduetohorizontal variability and not to vertical overturning. These waveform structures are probably due to the horizontal inhomogeneity of the density field and are likely caused by internal waves.

[1]  M. Doubell,et al.  Millimeter scale profiles of chlorophyll fluorescence: Deciphering the microscale spatial structure of phytoplankton , 2014 .

[2]  M. Doubell,et al.  An advanced laser-based fluorescence microstructure profiler (TurboMAP-L) for measuring bio-physical coupling in aquatic systems , 2009 .

[3]  J. Hiromi,et al.  Temporal variability in primary and copepod production in Sagami Bay, Japan , 2007 .

[4]  Edward R. Levine,et al.  On Measuring the Terms of the Turbulent Kinetic Energy Budget from an AUV , 2006 .

[5]  M. Levine,et al.  Tidally forced internal waves and overturns observed on a slope: Results from HOME , 2006 .

[6]  H. Yamazaki,et al.  Calibrating the Spatial Response of Bio-Optical Sensors , 2006 .

[7]  R. Lueck,et al.  Modeling the Spatial Response of the Airfoil Shear Probe Using Different Sized Probes , 2004 .

[8]  R. Lukas,et al.  Observations of Enhanced Diapycnal Mixing near the Hawaiian Ridge , 2002 .

[9]  Laurent Seuront,et al.  A New Free-Fall Profiler for Measuring Biophysical Microstructure , 2002 .

[10]  H. Yamazaki,et al.  Oceanic Velocity Microstructure Measurements in the 20th Century , 2002 .

[11]  K. Furuya,et al.  Size and species-specific primary productivity and community structure of phytoplankton in Tokyo Bay , 2000 .

[12]  N. S. Oakey,et al.  A Tethered Free-Fall Glider to Measure Ocean Turbulence , 1999 .

[13]  J. Wesson,et al.  Mixing at Camarinal Sill in the Strait of Gibraltar , 1994 .

[14]  A. Gargett,et al.  Local isotropy and the decay of turbulence in a stratified fluid , 1984, Journal of Fluid Mechanics.

[15]  T. Dillon.  Vertical overturns: A comparison of Thorpe and Ozmidov length scales , 1982 .

[16]  N. Oakey,et al.  Determination of the Rate of Dissipation of Turbulent Energy from Simultaneous Temperature and Velocity Shear Microstructure Measurements , 1982 .

[17]  J. A. Elliott,et al.  Dissipation Within the Surface Mixed Layer , 1982 .

[18]  Stephen Austen Thorpe,et al.  Turbulence and mixing in a Scottish Loch , 1977, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[19]  H. Yamazaki,et al.  A new tow-yo instrument to observe high-resolution coastal phenomena , 2014 .

[20]  S. Thorpe.  Measuring overturns with gliders , 2012 .

[21]  H. Yamazaki,et al.  Development of the Glider-type Turbulence Ocean Microstructures Acquisition Profiler, TurboMAP-G , 2010 .

[22]  Brian J. Rothschild,et al.  Biological-physical interactions in the sea , 2002 .

[23]  L. Seuront,et al.  Spatial Resolution of a New Micro-optical Probe for Chlorophyll and Turbidity , 2001 .

[24]  J. Moum,et al.  Upper Ocean Mixing Processes , 2001 .

[25]  C. Garrett.  Processes in the surface mixed layer of the ocean , 1996 .