1. Ekman Spiral
Boundary layer flow under horizontal homogeneous condition
Assuming steady state and neglecting thermodynamic effect,
Using K-theory
Further assuming
Boundary conditions

2. Is usually defined as the depth of the Ekman layer.
Atmosphere:
Ocean:

3. Oceanic Ekman layer
Boundary condition:
Solution:

4. Ekman transport The integrated water mass transport is at
layer
Ekman
layer
Ekman transport
The integrated water
mass transport is at
the right angle, 90
degree, to the wind
direction, known as
Ekman transport.

5. 4. Ocean gyre
Westerlies
North Pacific gyre
Easterlies

6. Estimate vertical secondary circulation
Is the depth of the
Ekman layer.
The integrated cross isobaric mass transport of the entire Ekman layer is

7. x y
Hurricane

8. Secondary circulation Boundary layer Ekman pumping Inflow Frictional
Pressure grad.
force
Centrifugal
force
Pressure grad.
force
Centrifugal
force
Secondary
circulation
Frictional
force
Inflow
Pressure grad.
force
Centrifugal
force
Boundary layer
Ekman pumping

9. Hurricane Vortex X L Converging Spin up Diverging Spin down Ekman
Pressure grad.
force
Coriolis
force L
Centrifugal
force
Converging
Spin up
Diverging
Spin down
Buoyancy X
Ekman
Pumping
Boundary
Layer
It is the convective clouds that generate spin up process to overcome the spin down process induced by the Ekman pumping