Off-line tracer applications based on Global HYCOM simulations

Garraffo, Z.*; Kamenkovich, I.*; Kim, H.-C.*; Kawamura, Hideyuki  ; Mehra, A.*; Rivin, I.*

Off-line tracer modeling is a powerful practical method to simulate tracer evolution using previously calculated velocity and density fields. The main advantage of this approach is in its computational efficiency, which permits extended simulations and multiple sensitivity runs. The off-line tracer model used for this work is based on the code originally developed for HYCOM by Rainer Bleck. It calculates the 3D mass transport from daily averaged velocities, as well as daily mean and instantaneous layer thicknesses. Current simulations are based on 1/12-degree HYCOM climatological runs. Examples of applications presented here include simulations of: (a) idealized tracers in the Southern Ocean; (b) radionuclides in the Pacific Ocean; (c) nutrients in the Pacific Ocean.