GEOL1100, Spring 2013

Global Physical/Descriptive Oceanography, or Notions for the Motions of the Oceans

Assignment 4, Due 3/14/13

This assignment revisits Ekman, Inertial Oscillation, and Geostrophic flow basics.

1. Descriptive Physical Oceanography, 7th ed. Chapter 7, SP7
2. Ocean Circulation, 2nd ed. Chapter 3.

Homework Assignment (Due 3/14)

1. Colling, OC Question 3.4
2. Ekman pumping rate: Suppose the westerly (eastward) wind stress in 0.1 N/m² at 40N and linearly decreases with latitude to -0.05 N/m^2 at 10N. Use matlab to calculate the wind stress and Coriolis parameter at latitudes 10N, 20N, 30N, 40N. Also calculate the Ekman horizontal velocity (you may assume that you want an average over the Ekman depth, which is the vertical integral divided by the layer depth, and you can use 50m as a guess for this depth) and the vertical velocity at the base of the Ekman layer at each latitude. Consider density to be constant. All relevant formulas are on the Shallow water equation slides. The formula for f in matlab speak is: Omega=7.29e-5; f0=2*Omega*sin(latitude*pi/180);
3. Colling, OC Question 3.5
4. Use the geostrophic relation and the hydrostatic relation to find the typical ratio between horizontal pressure gradient (|(dp/dx,dp/dy,0)|) and vertical pressure gradients (|dp/dz|), assuming:
   1. typical velocities are 0.1 m/s
   2. typical density is 1000 kg/m³
   3. typical gravity (g) is 10 m/s²
   4. typical f is 0.0001/s