Una Kim Miller

Physical oceanographer with a focus on moored time series, air-sea interaction, and ocean ventilation

I am currently a postdoc with Jaime Palter at the Graduate School of Oceanography, University of Rhode Island and am involved in the Gases in the Overturning and Horizontal circulation of the Subpolar North Atlantic Program (GOHSNAP). I received a Ph.D. in Earth and Environmental Sciences from Columbia University in 2023 and a B.S. in Oceanography from the University of Washington in 2015.

You can reach me at una.miller [at] uri.edu.


-- The role of the Labrador Sea in oxygenating the bottom limb of AMOC --

Deep convection in the Labrador Sea is thought to oxygenate the lower limb of the Atlantic Meridional Overturning Circulation (AMOC), bringing cold, oxygen-rich surface waters to the Atlantic Ocean interior. It has been speculated that a weakened AMOC will slow the export of oxygen to ocean interior, increasing regions of hypoxia and disrupting oceanic food chains. We are working to quantify the uptake and transport of oxygen in the Labrador Sea using an array of multi-year oxygen time series collected in and around the boundary currents of the Labrador and Irminger Seas.

-- High Salinity Shelf Water formation in the western Ross Sea --

High Salinity Shelf Water (HSSW) formed in the Ross Sea is a precursor to Antarctic Bottom Water (AABW), a water mass that drives the bottom limb of the global meridional overturning circulation (GMOC). Variability in the properties and production rates of AABW and its constituent water masses impacts the strength of GMOC, and thus the capacity of ocean to sequester atmospheric heat and carbon and to redistribute oxygen and nutrients. We used high-vertical-and-temporal-resolution salinity time series collected in austral winter 2017 from a mooring in the Terra Nova Bay (TNB) Polynya to estimate HSSW production rates and assess their variability in response to the katabatic wind regime. We also explored the timescales at which the surface brine rejection signal appears in response to katabatic winds and at which it mixes to depth to form HSSW. Read more: Miller et al. (2024)

-- Upper Ocean Turbulence Scaling --

Surface ocean turbulence is key to the transfer of heat, gas, and other important properties between the ocean and atmosphere but cannot be resolved in climate models, which instead rely on classic boundary layer scaling (BLS). However, the applicability of classic BLS in the ocean boundary layer is complicated by the presence of waves and wave-induced Langmuir circulation, the latter of which is thought to play an important role in mixed layer deepening and thus the ocean's role in atmospheric heat storage. We tested both classic and Langmuir-based BLS against measurements of turbulence kinetic energy (TKE) dissipation rate (ε) made using finescale velocity measurements from a moored pulse-coherent Acoustic Doppler Current Profiler (ADCP) in the Southeast Pacific "Stratus region", an area that climate models struggle to replicate.
Read more: Miller et al. (2023)



High Salinity Shelf Water production in Terra Nova Bay, Ross Sea from high-resolution salinity observations
Miller, U. , C. J. Zappa, A. L. Gordon, S.T. Yoon, C. Stevens, W.S. Lee. (2024)
Nature Communications

Scaling of moored surface ocean turbulence measurements in the Southeast Pacific Ocean
Miller, U. , C. J. Zappa, S. Zippel, J. T. Farrar, R. A. Weller. (2023).
Journal of Geophysical Research: Oceans

TKE Dissipation Rate Estimates from Pulse-Coherent ADCPs on Moorings .
Zippel, S, J. T. Farrar, C. J. Zappa; U. Miller , L. St. Laurent, T. Ijichi, R. A. Weller; L. McRaven; D. Le Bel. (2021).
Journal of Atmospheric and Oceanic Technology

Warming and inhibition of salinization at the ocean's surface by cyanobacteria
Wurl, O., K. Bird, M. Cunliffe, W. M. Landing, U. Miller, N. I. H. Mustaffa, et al. (2018).
Geophysical Research Letters

Analysis of bubble plume distributions to evaluate methane hydrate decomposition on the continental slope
Johnson, H. P., U. Miller, M. S. Salmi, E. A. Solomon, (2015).
Geochemistry, Geophysics, Geosystems , 16, 3825-3839.

Dissociation of Cascadia margin gas hydrates in response to contemporary ocean warming
Hautala, S. L., E. A. Solomon, H. P. Johnson, R. N. Harris, U. Miller (2014).
Geophysical Research Letters , 41, 8486-8494.