Tarry
Daniel R.
Tarry
Daniel R.
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Technical ReportCALYPSO 2019 Cruise Report: field campaign in the Mediterranean(Woods Hole Oceanographic Institution, 2020-01) Mahadevan, Amala ; D'Asaro, Eric A. ; Allen, John T. ; Almaraz García, Pablo ; Alou-Font, Eva ; Aravind, Harilal Meenambika ; Balaguer, Pau ; Caballero, Isabel ; Calafat, Noemi ; Carbornero, Andrea ; Casas, Benjamin ; Castilla, Carlos ; Centurioni, Luca R. ; Conley, Margaret ; Cristofano, Gino ; Cutolo, Eugenio ; Dever, Mathieu ; Enrique Navarro, Angélica ; Falcieri, Francesco ; Freilich, Mara ; Goodwin, Evan ; Graham, Raymond ; Guigand, Cedric ; Hodges, Benjamin A. ; Huntley, Helga ; Johnston, T. M. Shaun ; Lankhorst, Matthias ; Lermusiaux, Pierre F. J. ; Lizaran, Irene ; Mirabito, Chris ; Miralles, A. ; Mourre, Baptiste ; Navarro, Gabriel ; Ohmart, Michael ; Ouala, Said ; Ozgokmen, Tamay M. ; Pascual, Ananda ; Pou, Joan Mateu Horrach ; Poulain, Pierre Marie ; Ren, Alice ; Tarry, Daniel R. ; Rudnick, Daniel L. ; Rubio, M. ; Ruiz, Simon ; Rypina, Irina I. ; Tintore, Joaquin ; Send, Uwe ; Shcherbina, Andrey Y. ; Torner, Marc ; Salvador-Vieira, Guilherme ; Wirth, Nikolaus ; Zarokanellos, NikolaosThis cruise aimed to identify transport pathways from the surface into the interior ocean during the late winter in the Alborán sea between the Strait of Gibraltar (5°40’W) and the prime meridian. Theory and previous observations indicated that these pathways likely originated at strong fronts, such as the one that separates salty Mediterranean water and the fresher water in owing from the Atlantic. Our goal was to map such pathways and quantify their transport. Since the outcropping isopycnals at the front extend to the deepest depths during the late winter, we planned the cruise at the end of the Spring, prior to the onset of thermal stratification of the surface mixed layer.
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ArticleFrontal convergence and vertical velocity measured by drifters in the Alboran Sea(American Geophysical Union, 2021-03-24) Tarry, Daniel R. ; Essink, Sebastian ; Pascual, Ananda ; Ruiz, Simon ; Poulain, Pierre Marie ; Ozgokmen, Tamay M. ; Centurioni, Luca R. ; Farrar, J. Thomas ; Shcherbina, Andrey Y. ; Mahadevan, Amala ; D'Asaro, Eric A.Horizontal and vertical motions associated with mesoscale (10–100 km) and submesoscale (1–10 km) features, such as fronts, meanders, eddies, and filaments, play a critical role in redistributing physical and biogeochemical properties in the ocean. This study makes use of a multiplatform data set of 82 drifters, a Lagrangian float, and profile timeseries of temperature and salinity, obtained in a ∼1-m/s semipermanent frontal jet in the Alboran Sea as part of CALYPSO (Coherent Lagrangian Pathways from the Surface Ocean to Interior). Drifters drogued at ∼1-m and 15-m depth capture the mesoscale and submesoscale circulation aligning along the perimeter of fronts due to horizontal shear. Clusters of drifters are used to estimate the kinematic properties, such as vorticity and divergence, of the flow by fitting a bivariate plane to the horizontal drifter velocities. Clusters with submesoscale length scales indicate normalized vorticity ζ/f > 1 with Coriolis frequency f and normalized divergence of (1) occurring in patches along the front, with error variance around 10%. By computing divergence from drifter clusters at two different depths, we estimate minimum vertical velocity of (−100 m day−1) in the upper 10 m of the water column. These results are at least twice as large as previous estimates of vertical velocity in the region. Location, magnitude, and timing of the convergence are consistent with behavior of a Lagrangian float subducting in the center of a drifter cluster. These results improve our understanding of frontal subduction and quantify convergence and vertical velocity using Lagrangian tools.
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ArticleDrifter observations reveal intense vertical velocity in a surface ocean front(American Geophysical Union, 2022-09-03) Tarry, Daniel R. ; Ruiz, Simon ; Johnston, T. M. Shaun ; Poulain, Pierre Marie ; Ozgokmen, Tamay M. ; Centurioni, Luca R. ; Berta, Maristella ; Esposito, Giovanni ; Farrar, J. Thomas ; Mahadevan, Amala ; Pascual, AnandaMeasuring vertical motions represent a challenge as they are typically 3–4 orders of magnitude smaller than the horizontal velocities. Here, we show that surface vertical velocities are intensified at submesoscales and are dominated by high frequency variability. We use drifter observations to calculate divergence and vertical velocities in the upper 15 m of the water column at two different horizontal scales. The drifters, deployed at the edge of a mesoscale eddy in the Alboran Sea, show an area of strong convergence (urn:x-wiley:00948276:media:grl64766:grl64766-math-0001(f)) associated with vertical velocities of −100 m day−1. This study shows that a multilayered-drifter array can be an effective tool for estimating vertical velocity near the ocean surface.
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ArticleInertial oscillations and frontal processes in an Alboran Sea Jet: effects on divergence and vertical transport(American Geophysical Union, 2023-02-15) Esposito, Giovanni ; Donnet, Sebastien ; Berta, Maristella ; Shcherbina, Andrey Y. ; Freilich, Mara ; Centurioni, Luca ; D’Asaro, Eric A. ; Farrar, J. Thomas ; Johnston, T. M. Shaun ; Mahadevan, Amala ; Özgökmen, Tamay ; Pascual, Ananda ; Poulain, Pierre‐Marie ; Ruiz, Simón ; Tarry, Daniel R. ; Griffa, AnnalisaVertical transport pathways in the ocean are still only partially understood despite their importance for biogeochemical, pollutant, and climate applications. Detailed measurements of a submesoscale frontal jet in the Alboran Sea (Mediterranean Sea) during a period of highly variable winds were made using cross‐frontal velocity, density sections and dense arrays of surface drifters deployed across the front. The measurements show divergences as large as ±f implying vertical velocities of order 100 m/day for a ≈ 20 m thick surface layer. Over the 20 hr of measurement, the divergences made nearly one complete oscillation, suggesting an important role for near‐inertial oscillations. A wind‐forced slab model modified by the observed background frontal structure and with initial conditions matched to the data produces divergence oscillations and pattern compatible with that observed. Significant differences, though, are found in terms of mean divergence, with the data showing a prevalence of negative, convergent values. Despite the limitations in data sampling and model uncertainties, this suggests the contribution of other dynamical processes. Turbulent boundary layer processes are discussed, as a contributor to enhance the observed convergent phase. Water mass properties suggest that symmetric instabilities might also be present but do not play a crucial role, while downward stirring along displaced isopycnals is observed.Plain Language SummaryVertical transport pathways are essential for the exchange of properties between the surface and the deeper layers of the ocean. Despite the recognized role of vertical dynamics in biogeochemical and climate applications, it is still only partially understood. This is principally due to observational challenges. Vertical transport pathways are generally very localized processes and are associated with vertical velocities comparable to instrumental uncertainty. In this work, we focus on vertical processes occurring along a front at the edge of an eddy in the Mediterranean Sea. The paper combines the analysis of multiple observations with the use of an idealized numerical model to isolate and study surface divergence patterns. These analyses allow the investigation of the role of the wind forcing and of small‐scale ocean processes in vertical transport.Key PointsDivergence and vertical velocity oscillations are observed at a submesoscale front on the edge of an anticyclone in the Alboran SeaNear‐inertial oscillations play a major role in the observed divergence oscillatory pattern as suggested by a modified slab model of a wind‐forced frontal jetTurbulent boundary layer processes and symmetric instabilities can contribute to differences between modeled and observed vertical dynamics