Regionality and seasonality of small scales in the North Pacific

by Hideharu Sasaki (APL JAMSTEC)

Sasaki et al. (2017) investigated regionality and seasonality of small scales in the North Pacific by using the high resolution oceanic simulations. They conducted two OFES (OGCM for the Earth Simulator) North Pacific simulations at different horizontal resolutions of 1/30° and 1/10°. The comparison highlights the impact of small scales on kinetic energy (KE) and its seasonalily. In high KE regions of Kuroshio Extension, Subtropical Countercurrent, and Subtropical Eastern Pacific, mixed layer instabilty generating winter rich submesoscales (Figure 1) appears to be a main mechanism of KE seasonality, which leads the restratification and inverse energy cascade. In low KE regions of mid-latitude Eastern Pacific, and Subarctic Pacific, not so much mixed layer instability but large scale instability principally produce the KE seasonality.


Figure 1: Surface relative vorticity (1e-5 s-1) on March 1, 2002 in the North Pacific OFES simulations at (top) 1/30° and (bottom)1/10° horizontal resolutions.


From JAMSTEC, H. Sasaki (APL JAMSTEC) and Y. Sasai (RCGC JAMSTEC) contributed this paper. The ocean simulation using the OFES was conducted on the Earth Simulator under support of JAMSTEC.

Sasaki, H., P. Klein, Y. Sasai and B. Qiu: Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean, Ocean Dyn., in press,