Journal of Oceanography

, Volume 68, Issue 1, pp 139–150

Interannual variations in low potential vorticity water and the subtropical countercurrent in an eddy-resolving OGCM

Authors

    • Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Shang-Ping Xie
    • International Pacific Research Center (IPRC) and Department of Meteorology, School of Ocean and Earth Science and Technology (SOEST)University of Hawaii at Manoa
  • Hideharu Sasaki
    • Earth Simulator Center, JAMSTEC
Special Section: Short Contribution New developments in mode-water research: Dynamic and climatic effects

DOI: 10.1007/s10872-011-0042-3

Cite this article as:
Nonaka, M., Xie, S. & Sasaki, H. J Oceanogr (2012) 68: 139. doi:10.1007/s10872-011-0042-3

Abstract

Interannual-to-decadal variations in the subtropical countercurrent (STCC) and low potential vorticity (PV) water and their relations in the North Pacific Ocean are investigated on the basis of a 60-year-long hindcast integration of an eddy-resolving ocean general circulation model. Although vertically coherent variations are dominant for STCC interannual variability, a correlation analysis shows that an intensified STCC vertical shear accompanies lower PV than usual to the north on 25.5- to 26.1-σθ isopycnal surfaces, and intensified meridional density gradient in subsurface layers, consistent with Kubokawa’s theory (J Phys Oceanogr 29:1314–1333, 1999). The low-PV signals appear at least 2 years before peaks of STCC, propagating southwestward from the subduction region.

Keywords

Subtropical countercurrent Low potential vorticity water North Pacific Interannual variability Eddy-resolving ocean general circulation model

Copyright information

© The Oceanographic Society of Japan and Springer 2011