Island Wake in Deep/Shallow Water

Changming DongJames McWilliams

Alexander Shchepetkin

IGPP/UCLA

1. Island Effects in SCB

2. Island Wake in Deep Water

3. Island Wake in Shallow Water

Island Wakes in SCB

( a manuscript to be submitted to CSR)

RADARSAT SAR IMAGE (Caldeira et al, 2005)

LA

Two Types of Wakes

1. Deep Water: the vorticity is generated within lateral boundary of the island.

2. Shallow Water:

The vorticty is generated by two ways in homogenous ocean (Signell, 1989):

a. Slope Torque b. Speed Torque and additional one with stratification (Smolarkiewicz et al,

1989) c. Baroclinic tilting

Island Wake in Deep Water

(a manuscript submitted to JPO)

Centrifugal Instability

Barotropic and Baroclinic Instabilities

Reynolds Number

Rossby Number

Burger Number

Island Wake in Shallow Water (with Slope)

An additional nondimensional parameter: Internal Froude Number (Fr), must be introduced in the shallow-water wake.

Summary

1. In SCB, island wakes is very significant characterizing SCB circulation.

2. Three types of instabilities identified in deep-water island wakes,in which three nondimensional parameters (Re,Ro and Bu) are dominant.

3. In the shallow-water wake, an additional dimensionless parameter (Fr) is important.