I am a postdoctoral scholar at Scripps Institution of Oceanography working with advisor Teresa Chereskin. I work with large-scale models and observational datasets to study the ocean's role in a changing climate.


Research

My current work focuses on the momentum budget in the Southern Ocean, a dynamically unique region that governs much of the carbon and heat exchange between the deep ocean and the atmosphere. I use basin-scale model data from the Southern Ocean State Estimate (SOSE) to give a large-scale dynamical context to what we can see in regional observations from the cDrake Experiment.


Sources and sinks of momentum

Wind forcing at the surface of the Southern Ocean provides the momentum source, pushing the fluid eastward. Most (95%) of this momentum exits the ocean via topographic form stress, wherein the solid earth pushes back (westward) on the eastward flowing fluid (details here). The image below shows the six-year time mean wind stress field and topographic form stress field from SOSE, looking north from Antarctica. South America appears on the right, Australia in the middle, and the southern tip of Africa on the very top left; black lines show the mean Antarctic Circumpolar Current streamfunction.

Click to expand.



Interfacial form stress

Interfacial form stress (IFS) is one of the mechanisms that carries momentum from wind stress source to topographic sink. IFS transfers momentum from one fluid layer to another via pressure gradients across vertical perturbations in the interface that separates each layer. We map IFS in much the same way as topographic form stress (TFS) above, by directly determining the geostrophic transport balanced by these pressure gradients across interface perturbations.

The video below shows the daily evolution of geostrophic transport balanced by topographic (left) and interfacial (right) form stresses for the thermocline and intermediate water layer between the sea surface and the neutral density surface γ = 27.6 kg/m3. Blue indicates poleward transport, and red indicates equatorward transport. Poleward (blue) IFS transport largely balances the windstress-driven equatorward Ekman transport in this layer.




The distribution of TFS and IFS in the Southern Ocean sets the structure of the upwelling branch of the Meridional Overturning Circulation, a key nexus of heat and carbon exchange between the atmosphere and the deep ocean. A full description of these two fields can be found in the upcoming Interfacial form stress in the Southern Ocean State Estimate, in revision at JGR.

Publications

Masich, J., T. K. Chereskin, and M. R. Mazloff (2015), Topographic form stress in the Southern Ocean State Estimate, J. Geophys. Res. Oceans, 120, 7919–7933, doi:10.1002/2015JC011143. Link.

Manuscripts in prep

Masich, J., Mazloff, M. R., and Chereskin, T. K. Interfacial form stress in the Southern Ocean State Estimate. In revision, J. Geophys. Res. Oceans.

Masich, J., Chereskin, T. K., and Mazloff, M. R. Observational estimates of interfacial form stress in the northern Drake Passage. In prep.

CV (pdf)

EDUCATION
Scripps Institution of Oceanography, University of California, San Diego
Ph.D. in Physical Oceanography, September 2017
M.S. in Physical Oceanography, January 2014
Advisor: Teresa Chereskin
Committee: Sarah Gille, Matthew Mazloff, Dean Roemmich, Sutanu Sarkar, Lynne Talley

The University of Chicago
B. A. in Physics with General Honors, minor in Environmental Studies, June 2008
RESEARCH AND WORK EXPERIENCE
Scripps Institution of Oceanography, La Jolla, CA
Postdoctoral Researcher, Sept 2017 - present
Ph.D. Candidate, Jan 2014 - Sept 2017
Graduate Student Researcher, Jul 2010 - Jan 2014
Field work: cDrake Experiment mooring recovery and LADCP data processing aboard the R/V Palmer in Drake Passage, Nov-Dec 2011
Teaching: Teaching Assistant for Lynne Talley's graduate class Introduction to Physical Oceanography, Fall 2015

Environmental Protection Agency, Region 5, Chicago, IL
Environmental Scientist in Clean Water Act enforcement, July 2008 - July 2010

Woods Hole Oceanographic Institution, Woods Hole, MA
Summer Student Fellow with Ray Schmitt, June 2007 - September 2007
FELLOWSHIPS AND AWARDS
National Defense Science and Engineering Graduate Fellowship, September 2011 - September 2014
University of California Regents Graduate Fellowship, September 2010 - September 2011
Honorable mention, National Science Foundation Graduate Research Fellowship Program, 2011
Environmental Protection Agency Bronze Medal for Exceptional Service, 2009
PAPERS

Masich, J., Chereskin, T. K. and Mazloff, M. R. (2015), Topographic form stress in the Southern Ocean State Estimate.
J. Geophys. Res. Oceans. doi:10.1002/2015JC011143.

MANUSCRIPTS IN PREPARATION

Masich, J., Mazloff, M. R., and Chereskin, T. K. Interfacial form stress in the Southern Ocean State Estimate. In revision, J. Geophys. Res. Oceans.

Masich, J., Chereskin, T. K., and Mazloff, M. R. Observational estimates of interfacial form stress in the northern Drake Passage. In prep.

PRESENTATIONS

Masich, J., M. R. Mazloff, and T. K. Chereskin. Interfacial form stress in the Southern Ocean State Estimate. 2017. Poster presentation at Southern Ocean Workshop, Boulder, CO, Apr 2017.

Masich, J., T. K. Chereskin, and M. R. Mazloff. Momentum balance in the Southern Ocean. PC14D-2091, 2016. Poster presentation at Ocean Sciences Meeting, New Orleans, LA, Feb 2016.

Masich, J., T. K. Chereskin, and M. R. Mazloff. Sources and sinks of momentum in the Southern Ocean State Estimate. 80363, 2015. Poster presentation at American Geophysical Union Fall Meeting, San Francisco, CA, Dec 2015.

Millar, J. J., T. K. Chereskin, and D. R. Watts. Four-year observations of interfacial form stress in the northern Drake Passage. 14505, 2014. Poster presentation at Ocean Sciences Meeting, Honolulu, HI, Feb 2014.

Millar, J. J., T. K. Chereskin, and M. Mazloff. Exploring the Southern Ocean State Estimate in the Drake Passage: Assimilation and Analysis of an Inverted Echo Sounder Array. Oral and poster presentation at C-SOBOM NSF Science and Technology Center review Student and Postdoc Symposium, Princeton NJ, Oct 2012.

Millar, J. J., S. T. Gille, J. Sprintall, and M. Frantz. Assessing XCTD fall-rate errors using concurrent XCTD and CTD profiles in the Southern Ocean. OS21F-1565, 2010. Poster presentation at American Geophysical Union Fall Meeting, San Francisco CA, Dec 2010.

Millar, J. J. and R. W. Schmitt. Parameterizing the mixing due to salt fingers. 873, 2008. Poster presentation at Ocean Sciences Meeting, Orlando FL, Feb 2008.

Millar, J. J., C. Orellana, and N. Mujica. Experimental characterization of supercritical bifurcation in the presence of noise. Poster presentation at the Southern Workshop on Granular Materials, Vina del Mar, Chile, 2006