Exploring the upper ocean

Tandon Laboratory at UMass Dartmouth

Revealing the Submesoscale-Mesoscale Inverse Cascade: Research on Eddy Formation in the Brazil Current by Former Student Caique Luko

We are excited to share the latest research on Journal of Physical Oceanography led by our former student, Caique Luko, who has been making remarkable strides in the field of physical oceanography in the Brazil Current region. His recent article, titled “Topographically-generated submesoscale shear instabilities associated with Brazil Current meanders,” delves into the fascinating dynamics of the interaction of the Brazil Current and the convoluted topography in the Southeast Brazil.

Authors: Caique D. Luko, Cauê Z. Lazaneo, Ilson C. A. da Silveira (Advisor), Filipe Pereira, and Amit Tandon (Co-Advisor)

The western boundary current system off southeastern Brazil is comprised of two main currents: the poleward flowing Brazil Current (BC) in the upper layer and the equatorward flowing Intermediate Western Boundary Current (IWBC) beneath it. This intricate system exhibits recurrent cyclonic meanders between 22°S and 23°S, which grow quasi-stationarily through baroclinic instability. However, the specific triggers for these meanders have remained elusive until now.

This article sought to shed light on the mechanisms initiating the formation of these mesoscale eddies by incorporating the submesoscale component into the hydrodynamic scenario. They conducted a high-resolution numerical simulation using the Coastal and Regional Ocean COmmunity model (CROCO) at a regional 1/50° (∼2-km) resolution.

Their findings unveil an intriguing process: incoming anticyclones reaching the slope upstream of separation regions induce barotropic instability, thus serving as a trigger for meander formation. This, in turn, generates submesoscale cyclones, which, in conjunction with baroclinic instability, contribute to the growth of the meanders, resulting in a submesoscale-to-mesoscale inverse cascade. As the mesoscale cyclones continue to develop, they interact with the slope, generating inertially and symmetrically unstable anticyclonic submesoscale vortices and filaments.

The arrival of incoming anticyclones and the formation of CST eddies as depicted by stream function () and geostrophic velocity () maps derived from sea-surface height data from: (a-c) a CROCO simulated event; and (d-f) an altimetry observed event. Yellow boxes display snapshots of: (a and d) the incoming anticyclone from the east; (b and e) the anticyclone hitting the continental shelf-break; and (c and f) the formation of a CST eddy downstream. The 160 m isobath (solid white line) is shown to highlight the interaction of the incoming anticyclones with the shelf-break. Regions shallower than 160 m should be analyzed with caution on panels d-f due to the limitations of altimetry data within the shelf.

Caique Luko’s research not only enhances our understanding of the complex dynamics within the western boundary current system but also highlights the importance of considering submesoscale processes in the broader hydrodynamic context. His work opens new avenues for exploring the mechanisms underlying mesoscale eddy formation in the Brazil Current region.

We are immensely proud to share that Caique Luko has continued his academic journey as a Ph.D. student at the prestigious Scripps Institution of Oceanography. This remarkable accomplishment underscores his dedication, expertise, and passion for advancing our understanding of the oceans. We congratulate Caique on his significant contributions to the field of oceanography and look forward to witnessing the continued impact of his research.

For more information about Caique Luko’s article and his ongoing research, please follow him on ResearchGate.

Vicky featured on the UMassD feature story

Viktoriya was recently featured in the Feature stories section of UMassD. Find more about the different avenues she pursued before doing her undergraduate thesis in the Tandon Lab, in the article here.

Congratulations Vicky!

Two undergraduate students from Tandon lab participate in MassURC

Senior year undergraduate students, Nicholas Monroe and Viktoriya Balabanova, presented their respective research topics at recently concluded Massachusetts Undergraduate Research Conference (MassURC)  on April 28, 2023. This annual conference is organized by UMass Amherst.
Nicholas, along with Sid and Prof. Tandon,  presented his work on “Biases in the modeled air-sea interaction during 2017-18 in the Arabian Sea” and his talk can be accessed here.  On the other hand, Viktoriya talked about “Validating Geostrophic Balances in the North Atlantic Ocean”, which was co-authored with Sid, Dr. Farrar and Prof. Tandon. Her talk can be viewed here.

Congratulations Nicholas and Viktoriya!

Nicholas presenting his work at MassURC

Viktoriya presenting her work at MassURC

Tandon lab member presents an invited talk at EGU 2023 Meeting

Siddhant (Sid) Kerhalkar, a fourth year PhD candidate, recently participated and presented an invited talk on his research at the European Geophysical Union (EGU) 2023 Meeting in Vienna during April 23-28, 2023.  Sid utilized the hybrid format of the meeting and presented remotely on  “Observing and Modeling the variability of DWLs during the summer Monsoon in the Northern Indian Ocean” in the Ocean surface mixed layer session. This session was well attended both in-person as well as remotely.

Sid’s participation was supported by Graduate Studies Office, UMassD. Congratulations Sid!

A screenshot of Sid’s title slide

Interview from Former Fulbright Scholar visiting Tandon lab

United States-India Educational Foundation (USIEF), which is responsible for Fulbright fellowships, recently interviewed Dr.Shikha Singh to share her experiences while visiting the Tandon lab as a Fulbright-Kalam Climate scholar during 2019-20. The full interview can be watched here.

Congatulations Dr. Shikha Singh!

Filipe Pereira: Successfully Defended Ph.D. Thesis and Prestigious Postdoctoral Fellowship!

We are thrilled to share the wonderful news that the Ph.D. thesis defense of Filipe Pereira was successfully conducted on April 14th 2023.

Thesis Title: Physical-biological interactions in the Brazil Current meanders

Filipe is part of the University of São Paulo – UMass Dartmouth dual-degree program and displayed remarkable dedication throughout his research journey, leading to cutting-edge findings and enriching the scientific community. His tireless efforts and commitment to excellence have paved the way for new insights into the physics of the evolution of the quasi-stationary meanders of Brazil Current and its biological implications to local plankton community. Additionally, the dataset and analysis show that while the phytoplankton in mixed layer is influenced by the smaller processes at the edge of the large mesoscale eddy, at the pycnocline the plankton dynamics is dominated by the eddy pumping.

Stay updated on Filipe’s research by following their profile on ResearchGate!”

The defense was conducted under the guidance of a distinguished committee, whose expertise and guidance were instrumental in shaping and refining Filipe’s research. We extend our heartfelt gratitude to the following committee members:

– Prof. Ilson Silveira (USP Advisor)
– Prof. Amit Tandon (UMD Advisor)
– Prof. Áurea Ciotti (USP)
– Prof. Geoffrey Cowles (UMD)
– Prof. Peter Franks (UCSD)

The now Dr. Filipe Pereira has been awarded the highly prestigious University of California President’s Postdoctoral Fellowship (PPFP), recognizing his outstanding accomplishments and commitment to fostering a more diverse and equitable academic community. This esteemed program, with an impressive track record of success, has seen over 100 former fellows receive faculty appointments at various UC campuses, contributing to the ongoing diversification of the academic community within the University of California. He is going to work with Jen MacKinnon and Drew Lucas on understanding the role of the biology in the ocean optics during harmful algal blooms. Congratulations to Filipe on this remarkable and well-deserved honor!

Patrick featured on the UMassD feature story

Patrick was recently featured in the Feature stories section of UMassD. Find more about his non-tradiational student life and his research in the article here.

Congratulations Patrick!

Undergraduate students from Tandon Lab present at Sigma Xi exhibit, UMassD

Tandon lab was represented by two undergraduate students in the 27th annual Sigma Xi research exhibit held at Claire T. Carney Library, UMass Dartmouth in April 2023.

Nicholas Monroe presented a poster on “Biases in the modeled air-sea interaction during 2017-18 in the Arabian Sea”.  On the other hand, Viktoriya Balabanova presented about “Validating Geostrophic Balances in the North Atlantic Ocean”.  These posters were received well and accoladed by the judges and experts present there.

Congratulations Nicholas and Viktoriya!

(From L-R) Prof. Tandon, Viktoriya and Sid with Viktoriya’s poster

(From L-R) Nicholas, Sid and Prof. Tandon with Nicholas’ poster

Tandon lab at UMass IMS Symposium 2023

Inter-campus Marine Science (IMS) program at University of Massachusetts organized their annual symposium at UMass Dartmouth in March 2023. Researchers from the five UMass campuses (Amherst, Boston, Dartmouth, Lowell and Worcester) gather to discuss their work in marine sciences.

Sid presenting his work on DWLs

Sid Kerhalkar, Patrick Pasteris and Nicholas Monroe presented posters at this event and their posters can be found here.

Members of Tandon Lab participated in the CLIVAR air-sea interaction workshop

Prof. Amit Tandon and PhD candidates, Iury Simoes-Sousa and Siddhant (Sid) Kerhalkar, recently participated in the CLIVAR workshop on Mesoscale and Frontal-scale air-sea interaction in Boulder, Colorado between March 06-08, 2023. The goal of this workshop was to make use of the progress in air-sea interaction to identify gaps in understanding, facilitating, and improving comparison of observations and modeling, and to build collaborations to respond to community needs. This workshop was funded by US CLIVAR, NASA, NSF, NOAA and DoE.

In addition to participating in discussions, Iury and Sid were presenting posters on their respective research. Iury presented a poster on “Atmospheric Cold Pools in the Bay of Bengal”  while Sid’s poster was titled “Observing and Modeling the variability of DWLs during the summer Monsoon in the Northern Indian Ocean“.  Prof. Tandon also volunteered to participate as a discussion leader while Iury and Sid volunteered as note-takers for discussions.

Sid and Prof. Tandon with Sid’s poster

Iury and Prof Tandon with Iury’s poster






Iury and Sid are grateful for the financial support by the workshop organizers (and sponsors) to attend this workshop while Sid was additionally funded by the Graduate Student Senate (GSS), UMassD travel support.

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