Exploring the upper ocean

Tandon Laboratory at UMass Dartmouth

Dr. Amit Tandon Awarded the ‘Outstanding Graduate Faculty Research Mentor award’

On the day of the 3MT thesis competition finale (April 10, 2025), Prof. Tandon was awarded with the ‘2025 Outstanding Graduate Faculty Research Mentor‘ prize for his commitment to working with graduate students in research, knowledge creation and scholarship.

Colleagues and students gathered on the university’s main campus to honor his contributions to academia.

Congratulations Dr. Tandon!

(From Left) Dr. Ramana Patibandla, Debarshi Sarkar, Dr. Yanlai Chen, Dr. Amit Tandon, Siddhant Kerhalkar, Dr. Agata Piffer-Braga & Parth Sastry

Parth and Debarshi participates in the 3MT Thesis competition at UMass Dartmouth

Parth Sastry and Debarshi Sarkar recently participated in the 3 MT thesis competition held in Grand Reading Room at UMass Dartmouth. Organized by Office of the Associate Provost for Graduate Studies, Three Minute Thesis (3MT®) is a research communication competition which challenges graduate research students (PhD and Masters by Research) to present a compelling oration on their thesis topic and its significance in just three minutes.  The competition develops academic, presentation, and research communication skills and supports the development of research students’ capacity to effectively explain their research in language appropriate to a non-specialist audience.

Parth talked about his work on simulations of eddies in the eastern tropical Pacific and how they impact oxygen transport. Debarshi talked his research on biases in reanalysis products, their importance and how they affect the summer monsoon over the Indian subcontinent. It was an educational and a challenging experience for them to condense their research into an easily digestible, short, three-minute segment.

Debarshi presenting his poster.

Parth presenting his poster.

Can deep-sea water influence atmospheric ‘Black Carbon’ Concentrations?

A new paper led by Dr. Ashish Soni from IITM Pune with Dr. Tandon as a co-author highlights groundbreaking research on black carbon aerosols. This study, conducted in the Arabian Sea after the passage of cyclone Biparjoy collaboratively by Indian and USA scientific teams in the EKAMSAT science fieldwork conducted onboard R/V Roger Revelle in 2023, reveals that deep waters are a significant source of these black carbon aerosols. 

Congratulations Dr. Tandon!

More about the paper: Here

 

Tandon lab participates in the ASTRAL-EKAMSAT update meeting in UC Boulder, Colorado

Dr. Amit Tandon and Tandon Lab members Debarshi, Siddhant, and Ramana attended the EKAMSAT (Enhancing Knowledge of the Arabian Sea Marine Environment through Science and Advanced Technology) update meeting held on March 6–7, 2025. The meeting was hosted by Dr. Aneesh Subramaniam at the University of Colorado, Boulder. This two-day intensive meeting included a series of back-to-back sessions, where researchers from various collaborating universities and institutes shared updates on their work. These talks helped everyone stay on the same page and move closer to the goals of the EKAMSAT program.

Siddhant presented a 10-minute talk titled “Impacts of Salinity Stratification on SST in the Northern Indian Ocean Warm Pool” and Debarshi presented two 10-minute talks on air-sea heat flux biases in reanalysis products and the submesoscale variabilities in air-sea flux parameters during the time of monsoon transition.

Siddhant Kerhalkar presenting his talk.

Debarshi presenting one of his talks.

The meeting concluded with participants dividing into groups based on shared research interests. Each group worked on summarizing the main scientific findings from the talks and discussions and identifying key questions that still need to be addressed.

Work on “Cyclone Biparjoy’s Aftermath: Unveiling the Role of Small-Scale Ocean Processes in Wake Recovery” by Sid published in GRL

A new study led by Tandon lab PhD student Siddhant (Sid) Kerhalkar sheds light on the recovery of ocean thermal structures after cyclone passage, a largely unexplored area due to limited direct observations. As part of an international research effort in the Arabian Sea, Sid and his co-authors (including Dr Tandon) analyzed data from the R/V Thompson’s 2023 field campaign to study the aftermath of Cyclone Biparjoy. Their findings reveal that the cyclone’s slow movement, combined with monsoon winds, triggered small-scale oceanic processes that created asymmetrical temperature, salinity, and velocity structures in its wake—marking first such measurements in the region.

These observations were part of the “Enhancing Knowledge of the Arabian Sea Marine Environment through Science and Advanced Training (EKAMSAT)” program, an international collaboration funded by India’s Ministry of Earth Sciences and the U.S. Office of Naval Research. The initiative aims to improve monsoon prediction models by gathering critical oceanographic and atmospheric data in the Arabian Sea, a region that has been anomalously warm in recent years but remains less studied than many of the world’s oceans.

Our research shows that these submesoscale processes, play a critical role in accelerating the recovery of the ocean’s thermal structure after a cyclone”, said Sid. “This has major implications for ocean heat transport, nutrient distribution, and weather predictability, particularly for monsoon forecasts”.

The study highlights how oceanic processes influence air-sea heat exchange and climate dynamics, providing valuable insights for improving storm behavior and monsoon predictions, which are crucial for climate forecasting and disaster preparedness affecting nearly a third of the world’s population.

Siddhant’s research provides new observational evidence that will help refine predictive models for extreme weather events”, said Dr. Tandon.

The paper, titled “Monsoon-Frontal Interactions Drive Cyclone Biparjoy’s Wake Recovery in the Arabian Sea” is published in Geophysical Research Letters and is available at [here].

Fig: Schematic explaining the forcing conditions and the asymmetric response of the cold wake

Congratulations Sid and Dr Tandon!

How does Curvature at Ocean Fronts Influence Baroclinic Instability?

A recent study led by former post-doctoral fellow Dr. Suraj Singh, in collaboration with Dr. Amit Tandon and former research professor Dr. Christian E. Buckingham, titled ‘On baroclinic instability of curved fronts’, explores how introducing slight curvature to oceanic fronts impacts baroclinic instabilities.
The research extends the classic Eady and Charney models on a cylindrical polar coordinate system by adding a slight curvature to a predominantly zonal flow. Under quasi-geostrophic scaling, the team analyzed the structure and growth rates of the pressure perturbations.
A key finding reveals that while unstable Eady modes remain largely unaffected by curvature, unstable Charney modes deepen owing to the introduction of a depth scale, enhancing vertical buoyancy flux—a phenomenon highlighted in their results (figure below).
The study also acknowledges certain limitations and suggests that understanding curved fronts could improve future parametrization of baroclinic instabilities in ocean models, and eddies which are deeper than the mixed layers. (here)

Fig: Vertical structure of the along-front averaged buoyancy flux for several values of the radius of curvature (Fig 8 of the paper)

 

Dr. Amit Tandon Named Commonwealth Professor

In September 2024, Dr. Amit Tandon was felicitated with the title of Commonwealth Professor (here) at UMass Dartmouth, an achievement celebrated on November 4th, 2024, during the Faculty Recognition Ceremony.

Colleagues, students and family gathered on the university’s main campus to honor his contributions to academia.

Congratulations, Dr. Tandon, on this well-earned recognition!

Professor Tandon and graduate student Patrick Pasteris lead the development of Teledyne’s next-generation “Go-Anywhere” ocean profiling float.

Teledyne Marine, a global leader in developing deep ocean floats, recently highlighted the remarkable work of Dr. Amit Tandon and graduate student Patrick Pasteris in their recent feature.

They worked with four undergraduate engineering students for their capstone projects, with the help from the chief engineer from Teledyne Marine Bob Melvin and capstone instructor Prof. Hamed Samandari. The main objective of the project was to improve the design of the buoyancy engine and make the previous product more energy efficient. The students researched a combination of many components like pumps, motors, bladders, battery chemistries, in different ocean conditions to make the floats “Go-Anywhere”.

…The students were motivated and talented, working well as a team to engineer and test a concept…I look forward to more capstone opportunities”, said Teledyne chief engineer Bob Melvin.

More information in the article: here and on YouTube: here

Following the Monsoon Winds: Tandon Lab’s Expedition in the Bay of Bengal

Picture of R/V Thompson in the Bay of Bengal. (Picture: San Nguyen)

In the pursuit of advancing our understanding of the monsoons and air-sea interaction, Tandon Lab members recently participated in a remarkable 45-day field campaign (following the pilot cruise in 2023) as part of the EKAMSAT (Enhancing Knowledge of the Arabian Sea Marine Environment through Science and Advanced Training) program on R/V Thomas G Thompson. This collaborative effort involved scientists from the USA and India, with the U.S. team funded by the U.S. Office of Naval Research and the Indian team supported by the Ministry of Earth Sciences (MoES). NASA-funded scientists also joined the research team to examine the ocean ecosystem. Originally planned for the Arabian Sea, the fieldwork had to pivot to the Bay of Bengal due to geopolitical tensions in the region . Around 60 scientists from various prestigious institutions, including the University of Washington, Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, Columbia University, NOAA Center for Weather and Climate Prediction, University of Alaska-Fairbanks were part of this fieldwork. Indian institutions such as INCOIS, NIOT, NCMRWF, SAC-ISRO, and IITM-Pune also participated in the effort.

Objectives and Operations

The campaign aimed to study the atmospheric and oceanic boundary layer during the formation and destruction of a mini-warm pool in the Bay of Bengal. A mini-warm pool is a localized region of warm water that promotes water vapor convection, significantly impacting large-scale weather systems, such as the propagation of the monsoon. The team sought to observe the spatial extent of the mini-warm pool, the dynamics associated within it as this can affect regional weather patterns. The destruction of mini-warm pool or mixing of the warm water by the monsoon winds was also the focus of this study, amidst cyclones.

The fieldwork was split into two distinct legs. The first leg, from April 26 to May 14, 2024, focused on surveying the Bay of Bengal basin using an underway CTD (uCTD) to capture the spatial and vertical extent of the mini-warm pool across the Bay of Bengal basin. The team sailed from Chennai, India. Prof. Amit Tandon was one of the senior scientists on the first leg of the cruise, with Dr. Craig Lee from the University of Washington serving as the chief scientist. This phase also involved deploying autonomous instruments like wave-gliders, sea-gliders, and floats to measure various oceanographic parameters across a small part of the region.

EKAMSAT Leg-1 Science team (top). Prof Amit Tandon with AB Brian (bottom).

The second leg, from May 15 to June 15, 2024, led by Dr. Leah Johnson, focused on more detailed measurements using shipboard instruments like the FastCTD, Epsi, and T-Pads—cutting-edge devices developed by the Multi-scale Ocean Dynamics group at Scripps Institution of Oceanography. These instruments collected fine-scale ocean profiles. The configuration of the remote and shipboard instruments was aimed as to close the heat budget for the ocean and to understand the small-scale variabilities within the mini-warm pool’s dynamics. Radiosondes were also launched to collect atmospheric data, providing a more comprehensive view of how atmosphere evolved during the onset of the monsoon.

EKAMSAT Leg-2 Science team (Picture: San Nguyen)

 

Tandon Lab’s Contributions

Debarshi and Sid braving heavy rain and rough sea conditions during their deploying/monitoring instruments (Picture: San Nguyen and Kerstin Bergentz)

Sid Kerhalkar (PhD candidate at SMAST) and Debarshi Sarkar (PhD student in EAS program) from Tandon Lab braved challenging conditions—battling monsoon rains, tropical cyclones and high waves—while participating in watches to monitor, deploy, and recover shipboard instruments. Sid led the analysis of wave parameters during this fieldwork, while Debarshi contributed to the air-sea interaction analysis. In addition to their technical contributions, both were also involved in learning to launch radiosondes to capture atmospheric conditions during key periods of the monsoon.

Sid deploying the Radiosonde (Picture: Devmi Gamage)

Life at Sea

Beyond the scientific work, which bonded the team, life aboard the R/V Thomas G. Thompson was a unique experience. Daily science meetings provided an opportunity for the team to share findings from their earlier studies, discuss the upcoming weather and discuss new, exciting data collected during the cruise. Sid and Debarshi, along with their scientific contributions, added some flavor to ship life—quite literally! They were the part of the Indian-origin members of science team who volunteered to give the ship’s chefs a break for a meal, whipping up an Indian feast for the entire science team and crew (~60 people), which turned out to be a memorable event.

Sid (top left) and Debarshi (bottom left) busy cooking the Indian meal with the Indian team. Science team (right) seems happy with the meal serving. (Picture: San Nguyen and Sid Kerhalkar)

Sid also continued his hobby of video documentation, capturing the essence of life at sea and the exciting moments of the cruise—just as he had done in the previous year’s pilot expedition .

Underwater picture of Epsi profiler (top right), fishes (top left), T-Pads with fish in the background (bottom left) and a picture of sunset during the fieldwork (Picture: Sid Kerhalkar)

Despite the change in location, the EKAMSAT mission in the Bay of Bengal provided an invaluable opportunity to deepen the scientific community’s understanding of air-sea interaction during monsoon formation. The collaboration between international institutions and the deployment of cutting-edge technology highlighted the importance of such field campaigns in addressing complex climate phenomena. The data gathered will help inform future studies on how warm pools form, interact with atmosphere with respect to monsoon evolution, which eventually leads to its destruction, thus contributing to better weather forecasting globally and a deeper understanding of regional climate systems.

 

 

How effectively do NIOT’s moored buoys record Tropical Cyclones in the Bay of Bengal?

Dr. Amit Tandon, along with his colleagues from National Institute of Ocean Technology (NIOT) Chennai and Woods Hole Oceanographic Institute (WHOI), collaborated on the recently published paper: “Performance of Moored Real-Time Ocean Observations During Cyclones in the Bay of Bengal”.

This article provides a detailed explanation of the meteorological conditions, the air-sea flux conditions (measured and derived from COARE), the temperature and salinity depth profiles (and hence the mixed layer conditions) and the ocean current velocity profiles, as measured by the NIOT BD moorings, during Tropical Cyclone (TC) Amphan, which traversed through the Bay of Bengal at May 2020.

The authors highlight the benefits and necessity of maintaining such array of moored buoys in the Northern Indian Ocean, especially with the rise in the number and strength of TCs. They also discuss the challenges faced in data telemetry, mooring design, sensor exposure, etc. during cyclones and briefly outline NIOT’s plans for improving accuracy in generating and providing real-time data.

For more information: here

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