An accurate representation of air-sea interaction is crucial to the accurate numerical prediction of ocean, weather, and climate. It is
known that sea surface temperature (SST) gradients and surface currents in the oceanic mesoscale regime significantly affect air-sea fluxes of
momentum and heat, and the mesoscale-modified air-sea fluxes also influence the ocean dynamics on various scales. Previous studies found that
resolving the mutual feedbacks between mesoscale processes and the atmosphere improved the accuracy of modeling for ocean, weather, and climate.
In the submesoscale regime recently revealed by high-resolution numerical models and observations, the SST gradient and surface currents are
found to be much stronger than those in the mesoscale. However, the mutual feedbacks between the submesoscale processes and the atmosphere are
not well understood. To quantitatively assess the mutual responses between the air-sea fluxes and the submesoscale processes, a non-hydrostatic
ocean model coupled with an atmospheric boundary layer module is implemented making it possible to examine the air-sea interactions over
submesoscale regime. We here argue that the inclusion of surface currents in air-sea bulk flux parameterization and the atmospheric
thermodynamic adjustments to the ocean surface are determined to be significant for modeling accurate wind stress and air-sea turbulent heat
fluxes in the submesoscale regime. The results show that the linear relationship between wind stress curl/divergence and crosswind/downwind SST
gradient, revealed in the mesoscale regime, do not exist in the submesoscale regime. Additionally, the magnitudes of positive and negative wind
stress curl introduced by submesoscale processes are much greater than the magnitude of wind stress curl introduced by mesoscale processes. This
study also finds that the evolution of submesoscale processes is closely associated with the potential vorticity (PV) budget. Because different
fields of wind stress and turbulent heat fluxes are introduced by the influence of submesoscale surface velocity field and/or temperature field,
these wind stress and heat flux fields can interact with submesoscale surface structures and provide different PV injections into the ocean.
Therefore, the evolution of submesoscale processes is significantly influenced by the submesoscale-modified air-sea fluxes. This study serves as
a starting point in the investigation of the two-way feedback between the atmosphere and oceanic submesoscale processes. It shows that
numerically resolving the two-way air-sea coupling in the submesoscale regime significantly changes air-sea flux and the oceanic submesoscale
dynamics. / A Dissertation submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of
the requirements for the degree of Doctor of Philosophy. / Fall Semester 2018. / November 7, 2018. / air-sea interaction, numerical modeling, potential vorticity, submesoscale processes, surface turbulent heat fluxes,
wind stress / Includes bibliographical references. / William K. Dewar, Professor Co-Directing Dissertation; Eric Chassignet, Professor Co-Directing
Dissertation; Christopher Tam, University Representative; Mark A. Bourassa, Committee Member; Steve Morey, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_661126 |
| Contributors | Chen, Xu (author), Dewar, William K. (professor co-directing dissertation), Chassignet, Eric P. (professor co-directing dissertation), Tam, Christopher K. W. (university representative), Bourassa, Mark Allan (committee member), Morey, Steven L. (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean and Atmospheric Science (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, doctoral thesis |
| Format | 1 online resource (129 pages), computer, application/pdf |
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