pdf envelope rss-square Google Scholar profile Google Scholar profile ORCID ID Github

Deepak Cherian

physical oceanographer; project scientist I
National Center for Atmospheric Research
| +1 303-497-1713 | Mesa Lab 400


Small-scale turbulence & mixing, mesoscale oceanic eddies, baroclinic instabilities, continental shelf flow and equatorial dynamics. My toolkit includes observational records from moored and satellite platforms as well as high resolution realistic and idealized process-study models.

Linking microstructure measurements to the mesoscale

With Emily Shroyer (OSU), Jonathan Nash (OSU)


We are working to estimate lateral (mesoscale) diffusivity coefficients from two classes of microstructure measurements:

  1. moored measurements from the χpod of Moum & Nash (2009), and
  2. basin-wide GO-SHIP transects from the CTD-χpod (Pickering & Nash, unpublished).

We will interpret the χpod measurements using the triple decomposition framework of Garrett (2001). Above [left] is a preliminary estimate for the P06 section at 24°S in the Pacific Ocean. For comparison, we show an estimate based on Argo finestructure (Cole et. al., 2015) as well as an estimate using passive tracers advected by altimetric velocities (Abernathey & Marshall, 2013). [right] Density bins used for the computation are marked on a T-S plot.

Mixing measurements in the Bay of Bengal

With Emily Shroyer (OSU), Jim Moum (OSU) and the OSU Ocean Mixing Group | Read the paper! | More


Multiple year-long moored turbulent mixing measurements collected using fast temperature sensors (χ-pods) as part of the ASIRI/EBoB/RAMA programmes paint a picture of mixing across the Bay of Bengal that spans multiple time scales: interannual to diurnal and shorter.

Interesting signals include interannual & intraseasonal variability, a daily cycle in turbulence, depressed turbulence in barrier layers, elevated mixing associated with the tropical cyclones and a quiet ocean below 50m.

An estimate of the vertical structure of diffusivity KT is available here.

Shelf flows forced by mesoscale eddies

Advisor: Ken Brink (WHOI) | Read the paper! | More

One chapter of my thesis focused on the shelf flows forced by mesoscale eddies translating at the shelfbreak. The flow field is summarized below. What I found most interesting was the difference in vertical structure of the cross-shelfbreak flow. The shelf-water outflow is approximately vertically uniform whereas the eddy- and slope-water inflow is strongly sheared. Our paper explains why this happens.


Cross-shelfbreak exchange by mesoscale eddies

Advisor: Ken Brink (WHOI) | Read the paper! | More


My dissertation looked at the interaction of deep-ocean mesoscale eddies with continental shelf-slope topography.

When visualized using passive tracer fields (red tracks eddy water and blue, shelf-slope water), the interaction clearly results in the formation of smaller-scale secondary vortices. We term these 'stacked' vortices to reflect their (unexpected) vertical structure wherein shelf-slope water is stacked over eddy water. Observational evidence for these features remains elusive.

Here's a video showing the evolution of a passive tracer. The southern boundary is the coast, the eddy is started in the northeast in deep water (flat bottom) and the β > 0. The lower panel shows a time series of volume flux of shelf water: defined to be water parcels that start on the shelf at t=0. The shelf is ≈ 40 km wide and the continental slope is 50 km wide.

Inertial-gravity waves in the equatorial Pacific

With Tom Farrar (WHOI) & Ted Durland (OSU) | Code


Satellite observations give humanity an unprecedented detailed look at the surface ocean. The vertical structure of variability associated with surface signals is relatively less known, and the relevance of theoretical structures derived using strict assumptions is debated; viz., the so-called baroclinic vertical modes.

Motivated by the [zonal wavenumber]-frequency spectra of dynamic height calculated by Farrar & Durland (2012) — see image on right — my goal is to infer the vertical structure of 7-day period inertial-gravity waves in the equatorial Pacific (filter band marked by horizontal lines). I am using long term subsurface temperature measurements and inferred dynamic height from the TAO/TRITON project.


  • Rypina I.I., Pratt L.J.; Entner S.; Anderson A.; Cherian D.A. submitted. The Influence of an Eddy in the Success Rates and Distributions of Passively Advected or Actively Swimming Biological Organisms Crossing the Continental Slope. Journal of Physical Oceanography
  • Cherian, D.A., Shroyer, E.L., Wijesekera, H.W., Moum, J.N. (2020) The seasonal cycle of upper-ocean mixing at 8°N in the Bay of Bengal. Journal of Physical Oceanography. 50, 323-342 DOI PDF.
  • Cherian, D.A., Brink, K.H. (2018) Shelf flows forced by deep-ocean anticyclonic eddies at the shelfbreak. Journal of Physical Oceanography. 48, 1117–1138. DOI PDF.
  • Cherian, D.A., Brink, K.H. (2016) Offshore Transport of Shelf Water by Deep-Ocean Eddies. Journal of Physical Oceanography. 46 3599–3621. DOI PDF
  • Haine T.W.N., Cherian D.A. (2013) Analogies of Ocean/Atmosphere Rotating Fluid Dynamics with Gyroscopes: Teaching Opportunities. Bull. Amer. Meteor. Soc.. 94:684. DOI PDF Supplement
  • Brink K.H., Cherian D.A. (2013) Instability of an idealized tidal mixing front: Symmetric instabilities and frictional effects. Journal of Marine Research. 71(6):26. DOI PDF
  • Thesis: Cherian D.A. (2016) When an eddy encounters shelf-slope topography. PDF


While at MIT, I took the semester-long Teaching Certificate Program. I learned that it is generally more effective to have students work through a derivation primarily on their own in class with hints. Following that advice, I created worksheets that guide students through a derivation, guiding them toward important implications and reasoning for various steps. Here are the ones I have so far.

  1. Rossby adjustment - for OSU's Geophysical Waves class
  2. Non-hydrostatic internal waves - for OSU's Geophysical Waves class
  3. Sverdrup balance - for MIT's 12.808 - Observational Physical Oceanography

These are targeted at beginning graduate students. Any comments you might have on these are welcome. Please send me an email.

Latex source is also available on request.



Office Address: 1850 Table Mesa Drive, Mesa Lab 400, Boulder, CO

Phone: +1 303-497-1713



My work has been funded by the US National Science Foundation (NSF), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA) and the Office of Naval Research (ONR).

Styling gratefully borrowed from Ethan Schoonover, Nicolas P. Rougier and Matthew Butterick.

Icons from FontAwesome and Academicons.

Website built using Emacs Org-mode (source code)