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Andrey Shcherbina

Principal Oceanographer

Affiliate Assistant Professor, Civil and Environmental Engineering

Email

ashcherbina@apl.washington.edu

Phone

206-897-1446

Department Affiliation

Ocean Physics

Education

M.S. Physical Oceanography, Moscow Institute of Physics and Technology, 1998

Ph.D. Physical Oceanography, Scripps Institution of Oceanography, 2004

Andrey Shcherbina's Website

http://faculty.washington.edu/shcher/

Projects

Salinity Processes in the Upper Ocean Regional Study — SPURS

The NASA SPURS research effort is actively addressing the essential role of the ocean in the global water cycle by measuring salinity and accumulating other data to improve our basic understanding of the ocean's water cycle and its ties to climate.

15 Apr 2015

Lateral Mixing

Small scale eddies and internal waves in the ocean mix water masses laterally, as well as vertically. This multi-investigator project aims to study the physics of this mixing by combining dye dispersion studies with detailed measurements of the velocity, temperature and salinity field during field experiments in 2011 and 2012.

1 Sep 2012

APL-UW Involvement in the Coastal Margin Observation and Prediction Science and Technology Center (CMOP)

AUVs will be deployed by a newly formed APL-UW AUV group as part of CMOP's experimental observation network which consists of multiple fixed and mobile platforms equipped with oceanographic sensors.

More Info

15 Jun 2012

The Center for Coastal Margin Observation and Predication (CMOP) has purchased from Hydroid, LLC two Autonomous Underwater Vehicles (AUVs) for its studies. The REMUS (Remote Environmental Measuring Units) 100 (see Figure 1) is a compact, light-weight, AUV designed for operation in coastal environments up to 100 meters in depth. The AUVs will be deployed by a newly formed APL-UW AUV group as part of CMOP's experimental observation network which consists of multiple fixed and mobile platforms equipped with oceanographic sensors. The AUVs will be used, primarily, to study the Columbia River plume and estuary region. The AUVs will be deployed periodically throughout each operational year. We also plan to allow customization of the AUVs by integrating novel biogeochemical sensors to meet specific scientific objectives for the CMOP program.

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Publications

2000-present and while at APL-UW

High-resolution observations of the North Pacific transition layer from a Lagrangian float

Kaminski, A.K., E.A. D'Asaro, A.Y. Shcherbina, and R.R. Harcourt, "High-resolution observations of the North Pacific transition layer from a Lagrangian float," J. Phys. Oceanogr., 51, 3163-3181, doi:10.1175/JPO-D-21-0032.1, 2021.

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1 Oct 2021

A crucial region of the ocean surface boundary layer (OSBL) is the strongly-sheared and -stratified transition layer (TL) separating the mixed layer from the upper pycnocline, where a diverse range of waves and instabilities are possible. Previous work suggests that these different waves and instabilities will lead to different OSBL behaviours. Therefore, understanding which physical processes occur is key for modelling the TL. Here we present observations of the TL from a Lagrangian float deployed for 73 days near Ocean Weather Station Papa (50°N, 145°W) during Fall 2018. The float followed the vertical motion of the TL, continuously measuring profiles across it using an ADCP, temperature chain and salinity sensors. The temperature chain made depth/time images of TL structures with a resolution of 6 cm and 3 seconds. These showed the frequent occurrence of very sharp interfaces, dominated by temperature jumps of O(1)°C over 6 cm or less. Temperature inversions were typically small (less than about 10 cm), frequent, and strongly-stratified; very few large overturns were observed. The corresponding velocity profiles varied over larger length scales than the temperature profiles. These structures are consistent with scouring behaviour rather than Kelvin–Helmholtz-type overturning. Their net effect, estimated via a Thorpe-scale analysis, suggests that these frequent small temperature inversions can account for the observed mixed layer deepening and entrainment flux. Corresponding estimates of dissipation, diffusivity, and heat fluxes also agree with previous TL studies, suggesting that the TL dynamics is dominated by these nearly continuous 10-cm scale mixing structures, rather than by less frequent larger overturns.

Frontal convergence and vertical velocity measured by drifters in the Alboran Sea

Tarry, D.R., S. Essink, A. Pascual, S. Ruiz, P.-M. Poulain, T. Özgökmen, L.R. Centurioni, J.T. Farrar, A. Shcherbina, A. Mahadevan, and E. D'Asaro, "Frontal convergence and vertical velocity measured by drifters in the Alboran Sea," J. Geophys. Res., 126, doi:10.1029/2020JC016614, 2021.

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1 Apr 2021

Vertical transport generated by mesoscale and submesoscale flows plays a key role in the exchange of physical and biogeochemical properties between the surface and the ocean interior. Using multiple simultaneous drifter observations, we compute spatial gradients of velocity to obtain estimates of the divergence field. Thanks to the fact that drifters were deployed at two different depths, we can observe the vertical dependence of divergence in the upper 15 m and estimate the associated vertical velocity. In this study, we estimate divergence and vertical velocity in a ~1-m/s semipermanent frontal jet in the Alboran Sea by making use of a multiplatform data set including 82 drifters, a Lagrangian float, and along-shiptrack profile timeseries of temperature and salinity.

Restratification at a California Current upwelling front. Part I: Observations

Johnson, L., C.M. Lee, E.A. D'Asaro, L. Thomas, and A. Shcherbina, "Restratification at a California Current upwelling front. Part I: Observations," J. Phys. Oceanogr., 50, 14-55-1472, doi:10.1175/JPO-D-19-0203.1, 2020.

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6 May 2020

A coordinated survey between a subsurface Lagrangian float and a ship-towed Triaxus profiler obtained detailed measurements of a restratifying surface intensified front (above 30 m) within the California Current System. The survey began as downfront winds incited mixing in the boundary layer. As winds relaxed and mixing subsided, the system entered a different dynamical regime as the front developed an overturning circulation with large vertical velocities that tilted isopycnals and stratified the upper ocean within a day. The horizontal buoyancy gradient was 1.5 x 10-6 s-2 and associated with vorticity, divergence, and strain that approached the Coriolis frequency. Estimates of vertical velocity from the Lagrangian float reached 1.2 x 10-3 m s-1. These horizontal gradients and vertical velocities were consistent with submesoscale dynamics that are distinct from the classic quasigeostrophic framework used to describe larger-scale flows. Vertical and horizontal gradients of velocity and buoyancy in the vicinity of the float revealed that sheared currents differentially advected the horizontal buoyancy gradient to increase vertical stratification. This was supported by analyses of temperature and salinity gradients that composed the horizontal and vertical stratification. Potential vorticity was conserved during restratification at 16 m, consistent with adiabatic processes. Conversely, potential vorticity near the surface (8 m) increased, highlighting the role of friction in modulating near-surface stratification. The observed increase in stratification due to these submesoscale processes was equivalent to a heat flux of 2000 W m-2, which is an order-of-magnitude larger than the average observed surface heat flux of 100 W m-2.

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Inventions

Open Water Detection from Beneath Sea Ice

Record of Invention Number: 47655

Eric D'Asaro, Andrey Shcherbina

Disclosure

16 Mar 2016

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
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