Introduction to Physical Oceanography
Fall 2003
Homework #2
Due September 15
Using the equation of state (equation 2.1) in Knauss, calculate the following:
1. Calculate density and sigma for T = 28ºC, S = 30 psu at the sea surface.
2. Calculate density and sigma for T = 2ºC, S = 36 psu at a depth of 4000m
(4000 decibars).
3. Calculate density and sigma for T = 10.5ºC, S = 35.1 psu at the sea surface
4. Compute the density and sigma for the same range of values using the more
accurate UNESCO empirical density calculator.
(http://ioc.unesco.org/oceanteacher/resourcekit/M3/Converters/SeaWaterEqua
tionOfState/Sea%20Water%20Equation%20of%20State%20Calculator.htm)
5. How do the values of density computed with equation 2.1 and the online
calculator compare? Why would they be different?
6. Locate points a, b and c on the TS diagram below (Contours are of sigma).
Compute the following from equation 2.1 in Knauss:

7.
T

8.
S

9.
p
10. Based on these, how much would temperature have to change to cause the
same change in density as a change in salinity of 1 psu? How much would
the pressure have to change to cause the same change in density?