APL Home
APL-UW Home

Jobs
About
Campus Map
Contact
Intranet

Zoltan Szuts

Research Scientist/Engineer Senior

Email

zszuts@apl.washington.edu

Phone

206-685-8326

Education

B.A. Biology, Oberlin College, 2001

M.S. Oceanography, University of Washington, 2004

Ph.D. Oceanography, University of Washington, 2008

Publications

2000-present and while at APL-UW

Salinity transport in the Florida Straits

Szuts, Z.B., and C. Meinen, "Salinity transport in the Florida Straits," J. Atmos. Oceanic Technol., 30, 971-983, doi:10.1175/JTECH-D-12-00133.1, 2013.

More Info

1 May 2013

A submarine cable across the Florida Straits yields a time series of volume and temperature transports using previously determined calibrations, and here a calibration is defined for salinity transport using data not yet compared to the cable. Since 2001, 32 transects were collected with conductivity-temperature-depth (CTDs) sensors and lowered acoustic Doppler current profilers (LADCPs). Calibrations for volume and temperature transports using CTD/LADCP data are consistent with previous studies. A salinity calibration is obtained by regressing salinity transport against volume transport, where salinity transport is calculated relative to the basin-averaged salinity at 26°N (Sref = 35.156 psu). On average, the transect-derived salinity transport is 33.0 Sv psu (1 Sv ≡ 106 m3 s-1), has a standard deviation of 2.8 Sv psu, and has a 90th percentile range of 29.1–37.4 Sv psu. The cable-derived salinity transport has a root-mean-square error of 2.2 Sv psu compared to the CTD/LADCP transects. Inherent spatial fluctuations and their covariability in the Florida Straits are responsible for noise in the calibrations and for slight increases in accuracy from salinity to temperature to volume calibrations. Salinity fluctuations are strongest in middepth waters of intermediate salinity, where velocity is neither particularily fast nor variable. In contrast, temperature is highly stratified and warm near-surface waters coincide with fast and variable velocities. Temperature additionally exhibits seasonality near the surface, whereas no robust seasonality is found for salinity or velocity. Temperature and salinity transports are largely driven by volume transport, which in turn, because of a large average electrical conductivity, is closely related to the conductivity-weighted velocity that generates the cable-measured voltage.

Vertically averaged velocities in the North Atlantic Current from field trials of a Lagrangian electric-field float

Szuts, Z.B., and T.B. Sanford, "Vertically averaged velocities in the North Atlantic Current from field trials of a Lagrangian electric-field float," Deep Sea Res. II, 85, 210-219, doi:10.1016/j.dsr2.2012.07.022, 2013.

More Info

1 Jan 2013

A subsurface Lagrangian float that utilizes motional induction to calculate vertically averaged velocities was tested in the North Atlantic Current (NAC), taking advantage of existing cruises and infrastructure. The Electric Field Float (EFF) is a RAFOS float with horizontal electrodes that measures its own velocity by RAFOS tracking and calculates vertically averaged velocities when merged with the electrode system. The observations showed depth-averaged velocities that were fast in the core of the NAC (0.6 – 0.9 m s-1) and moderate in adjacent recirculations and eddies (0.3 – 0.4 m s-1). A float at 850 dbar moved at close to the depth-averaged velocity, while shallower floats followed surface intensified flow on top of the depth-averaged motion. Integral time scales of depth-averaged velocity (1.3 – 1.6 ± 0.4 d) are slightly shorter than time scales of float velocity (1.6 – 2.0 ± 0.3 d), while integral length scales of depth-averaged water velocity (35 ± 10 km for u, 18 ± 6 km for v) are slightly shorter than length scales of float motion (53 ± 12 km for u, 28 ± 6 km for v). Velocity spectra of depth-averaged velocity show significant variance at inertial periods. Quantitative and qualitative validation with multiple independent data sets confirms the accuracy of the instrument and sampling strategy in the NAC, advancing the limited observational knowledge of depth-averaged circulation in subpolar regions.

A vertical-mode decomposition to investigate low-frequency internal motion across the Atlantic at 26°N

Szuts, Z.B., J.R. Blundell, M.P. Chidichimo, and J. Marotzke, "A vertical-mode decomposition to investigate low-frequency internal motion across the Atlantic at 26°N," Ocean Sci., 8, 345-367. doi:10.5194/os-8-345-2012, 2012.

More Info

7 Jun 2012

Hydrographic data from full-depth moorings maintained by the Rapid/-MOCHA project and spanning the Atlantic at 26° N are decomposed into vertical modes in order to give a dynamical framework for interpreting the observed fluctuations. Vertical modes at each mooring are fit to pressure perturbations using a Gauss-Markov inversion. Away from boundaries, the vertical structure is almost entirely described by the first baroclinic mode, as confirmed by high correlation between the original signal and reconstructions using only the first baroclinic mode. These first baroclinic motions are also highly coherent with altimetric sea surface height (SSH). Within a Rossby radius (45 km) of the western and eastern boundaries, however, the decomposition contains significant variance at higher modes, and there is a corresponding decrease in the agreement between SSH and either the original signal or the first baroclinic mode reconstruction. Compared to the full transport signal, transport fluctuations described by the first baroclinic mode represent <25 km of the variance within 10 km of the western boundary, in contrast to 60 km at other locations. This decrease occurs within a Rossby radius of the western boundary. At the eastern boundary, a linear combination of many baroclinic modes is required to explain the observed vertical density profile of the seasonal cycle, a result that is consistent with an oceanic response to wind-forcing being trapped to the eastern boundary.

More Publications

Using motionally-induced electric fields to indirectly measure oceanic velocity: Instrumental and theoretical developments

Szuts, Z.B., "Using motionally-induced electric fields to indirectly measure oceanic velocity: Instrumental and theoretical developments," Prog. Oceanogr., 96, 108-127, doi:10.1016/j.pocean.2011.11.014, 2012.

More Info

1 Apr 2012

Measuring oceanic electric fields to calculate water motion is a mature technique that has been proven operationally.

A case study across the Gulf Stream at Cape Hatteras demonstrates practical application of the technique.

The accuracy of the 1D theory is quantified for the effect of steep topography and horizontal velocity gradients.

The 1D approximation is almost entirely valid, and errors are small (1–3 cm/s) and correctable by an iterative method.

Relationship between ocean velocity and motionally induced electric signals: 2. In the presence of sloping topography

Szuts, Z.B., "Relationship between ocean velocity and motionally induced electric signals: 2. In the presence of sloping topography," J. Geophys. Res., 115, doi:10.1029/2009JC006054, 2010.

More Info

5 Jun 2010

Motionally induced electric fields and electric currents in the ocean depend to first order solely on the vertical dimension. We investigate the significance of two-dimensional (2-D) perturbations that arise in the presence of sloping topography. The full electric response is calculated for a schematic geometry that contains a topographic slope, has a two-layer ocean with a layer of sediment beneath, and is described by five nondimensional parameters. When considered over the realistic ranges of topographic aspect ratio (the ratio of mean water depth to topographic width), topographic relief, sediment thickness, and sediment conductivity, velocity errors arising from 2-D perturbations are found to be less than a few percent of the dominant one-dimensional (1-D) signal. All errors depend on the topographic aspect ratio to the power of 1.9 and have linear dependence on topographic relief and the depth of the surface jet. Depth-uniform velocity errors are roughly proportional to the 1-D sediment conductance ratio, whereas depth-varying velocity errors are independent of sediment thickness or conductivity. Two-dimensional perturbations decay with a half width of 0.2–1 times the 1-D effective water depth. The magnitude of estimated errors is consistent with those found at a measurement location with strong 2-D perturbations. This study extends the first-order theory to the maximum expected aspect ratios for topography and finds small perturbations with simple dependencies. Overall, the 1-D approximation is found to be adequate for interpreting observations at all but the most extreme locations.

Relationship between ocean velocity and motionally induced electrical signals: 1. In the presence of horizontal velocity gradients

Szuts, Z.B., "Relationship between ocean velocity and motionally induced electrical signals: 1. In the presence of horizontal velocity gradients," J. Geophys. Res., 115, doi:10.1029/2009JC006053, 2010.

More Info

5 Jun 2010

Motionally induced electric fields and electric currents in the ocean depend to first order solely on the vertical dimension. We investigate the significance of two-dimensional (2-D) perturbations that arise in the presence of horizontal velocity gradients. The full electric response is calculated for two schematic geometries that contain horizontal velocity gradients, have a two-layer ocean with a layer of sediment beneath, and are described by four nondimensional parameters. When considered over the realistic ranges of oceanic aspect ratio (the ratio of water depth to the width of velocity), sediment thickness, and sediment conductivity, velocity errors arising from 2-D perturbations are found to be less than a few percent of the dominant one-dimensional (1-D) signal. All errors depend on the aspect ratio to the power of 1.9 (1) for signals induced by the vertical (horizontal) component of the Earth's magnetic field. Depth-uniform velocity errors are proportional to the 1-D sediment conductance ratio, whereas depth-varying velocity errors are independent of sediment thickness or conductivity. Errors are weakly (proportionally) dependent on the jet depth for signals induced by the vertical (horizontal) component of the magnetic field. Two-dimensional perturbations decay away from the forcing region with a half width of 0.2–1 times the 1-D effective water depth. This study extends the first-order theory to the maximum expected aspect ratios for oceanic flow and finds small perturbations with simple dependencies on the nondimensional parameters.

The First PACSWIN Submarine Cable Workshop

You, Y., T. Sanford, C.-T. Liu, P. Sigray, M. Koga, W. Pandoe, J. H. Lee, N. Palshin, Z. Szuts, and K. Taira, "The First PACSWIN Submarine Cable Workshop," In CLIVAR
Exchanges, 14, 11-13, 2009.

1 Oct 2009

The Interpretation of Motionally Induced Electric Fields in Oceans of Complex Geometry

Szuts, Zoltan B., "The Interpretation of Motionally Induced Electric Fields in Oceans of Complex Geometry," APL-UW TR 0803, October 2008.

30 Oct 2008

Electric Field Floats in the North Atlantic Current: Validation and Observations

Szuts, Z.B., "Electric Field Floats in the North Atlantic Current: Validation and Observations," APL-UW TR 0405, June 2004.

30 Jun 2004

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
Close

 

Close

 

Close