Q A cruise goes out and makes temperature measurements at two locations 25 km apart as follows:
| z (m) | T1 (\(\mathrm{^oC} \)) | T2 (\(\mathrm{^oC}\)) |
| 10 | 10.4 | 10.1 |
| 30 | 8.7 | 8.4 |
| 50 | 4.7 | 5.2 |
| 70 | 4.1 | 4.8 |
The density of fresh water at 10 degrees is 1008 kg/m^3. What is the approximate density at each depth if the water is fresh? (i.e. you can ignore compressive effects and non-linearities in the equation of state).
Q What direction would you expect the water to be flowing at each depth?
Q Approximate the strength and sign of the horizontal hydrostatic pressure gradient at 20, 40, 60 and 80 m, assuming a flat sea surface. Make sure you write out the equation so I can check your math. Does your answer make sense with the answer above? Hint: discretize the water column by assuming that it consists of 4 20-m layers of water, each with a constant temperature. Also, don’t round off your density values too much!
Q What must the difference in the sea surface height be at the two stations for your estimated horizontal pressure gradient to be zero at 40 m?