Parameterization of mixing by secondary circulation in estuaries


Basdurak N. B. , Huguenard K. D. , Valle-Levinson A., Li M., Chant R. J.

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, cilt.122, sa.7, ss.5666-5688, 2017 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 122 Konu: 7
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1002/2016jc012328
  • Dergi Adı: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
  • Sayfa Sayıları: ss.5666-5688

Özet

Eddy viscosity parameterizations that depend on a gradient Richardson number R-i have been most pertinent to the open ocean. Parameterizations applicable to stratified coastal regions typically require implementation of a numerical model. Two novel parameterizations of the vertical eddy viscosity, based on Ri, are proposed here for coastal waters. One turbulence closure considers temporal changes in stratification and bottom stress and is coined the "regular fit.'' The alternative approach, named the "lateral fit,'' incorporates variability of lateral flows that are prevalent in estuaries. The two turbulence parameterization schemes are tested using data from a Self-Contained Autonomous Microstructure Profiler (SCAMP) and an Acoustic Doppler Current Profiler (ADCP) collected in the James River Estuary. The "regular fit'' compares favorably to SCAMP-derived vertical eddy viscosity values but only at relatively small values of gradient Ri. On the other hand, the "lateral fit'' succeeds at describing the lateral variability of eddy viscosity over a wide range of Ri. The modifications proposed to R-i-dependent eddy viscosity parameterizations allow applicability to stratified coastal regions, particularly in wide estuaries, without requiring implementation of a numerical model.