Mixing and transport processes in estuaries, river plumes, and buoyant flows.
Please visit my website for complete information
I work to better understand the mixing and transport processes driving this water mass transformation in the estuarine and coastal regions as these processes ultimately control the fate of freshwater and the water mass structure on the continental shelf. To advance this pursuit I develop novel analytical tools and utilize numerical models along with observational oceanographic and meteorological data in an attempt to capture and advance the understanding of the underlying physical processes.
Dramatic transformations occur as water masses transition from fresh riverine water to open ocean composition. Turbulent mixing processes are responsible for the bulk of the mixing required for this transformation, which occurs within the estuary and the buoyant river plume that is discharged into the coastal ocean. These are dynamic regions with an inherently high degree of spatial and temporal variability which has led to important aspects of the mixing and transport processes remaining elusive.
My current work focuses on the turbulent mixing processes in the tidal plume of the Columbia River. The large scale far-field structure of a river plume and its response to various external forcing variables has typically been considered sub-tidal phenomenon generally disconnected from estuarine processes. However, within a tidal excursion of the mouth of the estuary the tidal river plume is essentially an extension of the estuary into the coastal ocean. Recently it has become apparent that tidally driven processes in this region can potentially set-up the structure of the far-field plume; however, the dominant mixing processes/regions are still not well understood.
My previous work has focused on the large scale response of buoyant river plume systems to wind forcing. Specifically, I examined the role of cross-chore winds and shelf circulation on the structure of the Hudson River plume and the freshwater transport pathways in the Mid-Atlantic Bight (MAB). Using the Regional Ocean Modeling System (ROMS) I created idealized and realistic model domains with idealized and realistic forcing parameters to examine the underlying physical response to the cross-shore winds that are regularly observed on the New Jersey coast in the winter. The numerical results combined with observational data analysis have led to the development of a new theory on the response of buoyant plumes to cross-shore winds and a new understanding of the factors controlling the dominant freshwater transport pathways in the MAB. The structure and offshore position of a plume subjected to offshore directed winds was found to reach a relative steady state dependent on the structure and strength of the estuarine forcing and ambient shelf circulation.
For my post-doc work with Jonathan Nash at Oregon State I am working to describe the turbulent mixing at the tidal plume front and the stratified, sheared plume region and determine the dominant mixing processes and regions driving the total integrated plume entrainment using an extensive dataset of turbulence measurements in the tidal Columbia River plume.
The evolution of the frontal structure and turbulence was captured by continually sampling the plume using a turbulence profiler as the ship followed the tidal plume front as it propagated offshore. Capturing the evolution of the front for several tidal plumes over a range of tidal and river forcing regimes has allowed for the characterization and development of parameterizations for the turbulent dissipation in the frontal and stratified/sheared regions of the plume. Formulations for dissipation in the stratified and sheared region of the plume behind the front have been developed based solely on bulk plume properties in the form of the bulk Richardson number, and turbulent dissipation in the frontal region has been correlated with the amplitude of the front. The dissipation parameterizations are particularly interesting as they show strong dependencies on external forcing parameters, suggesting the possibility of a reliable scaling for the turbulent mixing in a tidal plume based on external, prognostic parameters.
Ph.D., Oceanography, 2012
Rutgers, The State University of New Jersey
Advisor: Bob Chant
B.S., Marine Science with minor in Mathematics, 2006
University of South Carolina
Advisor: Richard Styles
I have a courtesy faculty appointment in CEOAS working with Jonathan Nash and the OSU Ocean Mixing Group
Jurisa JT and J Nash (in prep). The relevance of frontal mixing to the evolution of an energetic tidal river plume. To be submitted to Journal of Geophysical Research
Styles R, Borgianini S, Brodie R, and JT Jurisa (2014). Application of a particle transport model in the vicinity of a river tidal boundary. Journal of Coastal Sciences, 1(2), 1-10
Jurisa JT and RJ Chant (2013). Impact of offshore winds on a coupled buoyant river plume/estuarine system. Journal of Physical Oceanography, 43, 2571-2587.
Jurisa JT and RJ Chant (2012). The coupled Hudson River estuarine-plume response to variable wind and river forcings. Ocean Dynamics, 62, 771-784.